Friction damper

Description

[0001] This patent application claims priority from German patent application DE 10 2020 202 348.4, the contents of which are incorporated herein by reference.

[0002] The invention relates to a friction damper.

[0003] A friction damper is known from DE 103 58 204 A1.

[0004] A direction-dependent friction damper is known from EP 3 296 587 A1. Depending on the actuation direction of a plunger, either an extension friction or a different insertion friction is effective.

[0005] It is the object of the present invention to provide a friction damper with extended functionality.

[0006] This object is achieved according to the invention by a friction damper having the features specified in claim 1.

[0007] According to the invention, it was recognized that expanded functionality is possible for a friction damper that has a switching unit. The switching unit serves to variably determine a friction force. The friction force is generated by a friction unit in a direction-dependent manner. The friction force acts on a plunger that can be displaced along a longitudinal axis of a housing of the friction damper. The friction force generated by the friction unit is direction-dependent, in particular dependent on the direction of displacement of the plunger, i.e. along a direction in which the plunger is pulled out of the housing or along a direction in which the plunger is inserted into the housing. Direction-dependent means that the friction force in the insertion direction differs in magnitude from the friction force in the extension direction.In particular, the frictional force acting in the extension direction, also referred to as extension friction, is greater than the frictional force acting in the insertion direction, also referred to as insertion friction. To generate the frictional force, the friction unit has at least one friction lining that frictionally rests against the tappet.

[0008] The friction force can be variably set using the switching unit. In particular, the amount of friction can be variably set, in particular in steps. In particular, the amount of friction can be set direction-dependently and / or direction-independently. In particular, the amount of friction is set in the extension direction and can be variably set in the insertion direction, in particular increasing along the insertion direction. This means that when the plunger is actuated in the insertion direction, the further the plunger is pushed into the housing, the greater the friction force. The amount of friction is in particular amplitude-dependent. The amount of friction is in particular direction-dependent. To variably set the friction force, the switching unit cooperates with the friction unit.If the friction force is set by the switching unit for an extreme position of a friction lining carrier of the friction unit, the friction force is not direction-dependent but direction-independent. This means that the friction force is direction-independent in the extreme positions of the friction lining carrier if it is set by the switching unit. In this case, the magnitude of the friction force is identical in the insertion direction and in the extension direction. The extreme positions are, in particular, a minimum position and a maximum position of the friction lining carrier. In the minimum position of the friction lining carrier, in particular, a minimum insertion force is exerted on the plunger in the insertion direction. In the maximum position, in particular, a maximum friction force is exerted on the plunger in the insertion direction. Between the extreme positions, the friction lining carrier can also assume at least one intermediate position.The friction lining carrier can also assume a plurality of different intermediate positions, in particular at least two intermediate positions, in particular at least three intermediate positions, in particular at least four intermediate positions, in particular at least five intermediate positions, in particular at least ten intermediate positions, in particular at least 15 intermediate positions, and in particular at most 20 intermediate positions. It is particularly possible to fix the friction lining carrier in the at least one intermediate position by means of the switching unit in such a way that actuation of the plunger in the insertion direction causes a displacement of the friction lining carrier and thus changes the friction force in the insertion direction, whereas actuation of the plunger in the extension direction does not cause any displacement of the friction lining carrier, so that a constant friction force acts in the extension direction.

[0009] A design of the friction unit with a friction lining carrier to which the at least one friction lining is held, wherein the friction lining carrier is arranged so as to be displaceable relative to the tappet between an extended position and a inserted position, enables a direct and uncomplicated generation of the direction-dependent friction force. The friction unit has, in particular, several friction linings, in particular exactly two, in particular more than two, in particular at least three, in particular at least four, and in particular at most twenty. The friction unit acts passively. By means of the friction lining carrier, which is arranged in particular in the housing, the extraction friction or the insertion friction can be generated by displacing it between an extended position and an inserted position. By changing the position of the friction lining carrier between the extended position and the inserted position, the arrangement of the at least one friction lining relative to the tappet is also changed.As a result, the amount of frictional force changes depending on the direction of displacement of the plunger.

[0010] The switching unit serves, in particular, to switchably lock the friction lining carrier, particularly in the extended position and / or in the inserted position. Locking blocks the movement of the friction lining carrier. In the extreme positions of the friction lining carrier, the arrangement of the at least one friction lining relative to the plunger is fixed, regardless of the plunger's direction of movement. In the locked arrangement of the friction lining carrier, the magnitudes of the extension friction and the insertion friction are identical.

[0011] In particular, the friction unit interacts with the plunger in such a way that the friction lining carrier is moved into the extended position when the plunger is moved in the extension direction, and into the inserted position when the plunger is moved in the insertion direction. The displacement of the friction unit results directly from the displacement of the plunger, in particular from the friction force between the at least one friction lining and the plunger. The displacement of the friction unit is integrated into the typical actuation sequence of the friction damper.

[0012] Tilting the friction lining carrier, which is arranged in the housing so that it can be tilted about a tilt axis, simplifies the change between the extended position and the inserted position. The tilt axis is in particular arranged so that it is fixed to the housing. The tilt axis is oriented transversely to the longitudinal axis of the housing. In particular, the tilt axis is oriented essentially perpendicular to the longitudinal axis, whereby angular deviations of + / - 15° with respect to a perpendicular orientation to the longitudinal axis for the tilt axis are conceivable. In particular, the angular orientation between the tilt axis and the longitudinal axis is between 75° and 105°, in particular between 80° and 100°, in particular between 85° and 95°, in particular between 87° and 93°, in particular between 88° and 92°, in particular between 89° and 91° and in particular exactly 90°. In particular, a tilt pin is arranged in the housing, to which the friction lining carrier is hinged so that it can be tilted and has a tilt opening. The tilt pin defines the tilt axis.The tiltability of the friction lining carrier is simplified. The friction lining carrier is also called a tilting piston.

[0013] In particular, the tilting axis is arranged at a distance from the longitudinal axis, in particular skewed relative to the longitudinal axis. Due to the distance between the tilting axis and the longitudinal axis, tilting of the friction lining carrier, i.e., switching between the extended and inserted positions, is advantageously possible. In particular, a torque relative to the tilting axis is directly applied to the friction lining carrier depending on the actuation of the plunger in the insertion or extension direction.

[0014] An embodiment of the friction lining carrier according to claim 2 ensures a straightforward and reliable arrangement of the at least one friction lining in a friction lining receptacle provided for it. In particular, at least one, and in particular exactly one, friction lining receptacle is provided for each friction lining. In particular, several, in particular two, friction lining receptacles are integrated into the friction lining carrier, with a friction lining being arranged in each friction lining receptacle.

[0015] An embodiment of the friction damper according to claim 3 enables improved, in particular more efficient, generation of frictional force. It is conceivable for the friction linings to be identical. The manufacturing effort for the friction damper is reduced. The friction linings have, in particular, a contour that corresponds to the outer contour of the tappet. The friction linings can bear flatly, in particular over their entire surface, against the tappet. The generation of frictional force is efficient. The friction linings have, in particular, a half-shell contour. The half-shell contour is an open tubular cross-section. The inner contour of the half-shell is, in particular, an inner cylinder surface. It is also conceivable for the tappet to have a cross-sectional area oriented perpendicular to the longitudinal axis, which is non-circular, in particular oval or polygonal. The inner contour of the friction lining is designed accordingly in this case. It is also conceivable for the friction lining to be designed with one or more friction strips.A friction strip is essentially flat. The friction strip is particularly flexible, so that the friction strip assumes the contour corresponding to the tappet, particularly when inserted into the friction lining receptacle. In particular, the friction lining receptacle has a contour corresponding to the tappet.

[0016] An embodiment of the friction lining carrier according to claim 4 enables effective friction damping. The at least one friction lining can be arranged in a radial direction relative to the longitudinal axis between the inner tappet and the outer friction lining carrier. In particular, the at least one friction lining is pressed radially against the tappet by the friction lining carrier. The friction lining carrier with a through-opening enables a compact design of the friction unit.

[0017] An embodiment of the through-opening according to claim 5 enables advantageous switching between the extended position and the inserted position. In particular, collision-free tilting of the friction lining carrier relative to the tappet between the extended position and the inserted position is possible. A through-opening of the friction lining carrier provides the clearance required for switching between the extended position and the inserted position. An asymmetrical contour of the through-opening is achieved, for example, by the contour having a dividing line. The through-opening, in particular, has an asymmetrical inner contour. The asymmetrical inner contour can be designed symmetrically in sections and, for example, as a circular segment. Symmetrical means rotationally symmetrical to the longitudinal axis.The asymmetrical inner contour has at least one asymmetrical section, which is in particular non-circular. Several asymmetrical sections, in particular those designed separately from one another, can also be provided. It is important that the asymmetrical inner contour is at least partially not rotationally symmetrical with respect to the longitudinal axis. Asymmetrical means in particular not rotationally symmetrical with respect to the longitudinal axis oriented perpendicular to the contour. The dividing line is in particular a straight line, which in particular intersects the longitudinal axis. The dividing line symbolizes a parting plane that extends along the longitudinal axis. The dividing line can also be curved or kinked. The dividing line divides the contour of the through-opening into a symmetrical, in particular round, contour section and an asymmetrical, in particular non-circular contour section.The dividing line separates the symmetrical contour section and the asymmetrical contour section.

[0018] An embodiment of the through-opening according to claim 6 ensures that the friction lining carrier is arranged with either a first or a second through-opening section parallel to the longitudinal axis of the housing, depending on the tilting position. The through-opening sections each have a section longitudinal axis that is arranged at an angle to one another. The section longitudinal axes are oriented in particular such that, in the extended position of the friction lining carrier, a first section longitudinal axis is arranged parallel to the longitudinal axis of the housing and a second section longitudinal axis is arranged at an angle to the longitudinal axis of the housing. Accordingly, in the inserted position, the second section longitudinal axis is arranged parallel to the longitudinal axis of the housing and the first section longitudinal axis is arranged at an angle to the longitudinal axis of the housing.

[0019] A friction lining receptacle according to claim 7 enables reliable and secure mounting of the friction lining on the friction lining carrier. The friction lining is held in the friction lining receptacle, in particular in the radial direction and / or in the axial direction relative to the longitudinal axis of the housing and / or the section's longitudinal axis. The friction lining receptacle, in particular, has a depth that is slightly smaller than the thickness of the friction lining, so that the friction lining is permanently pressed against the tappet in the radial direction. The friction lining receptacle has a length oriented along the longitudinal axis that approximately corresponds to the length of the friction lining. The friction lining is then held reliably and axially non-preloaded in the friction lining receptacle. It is also conceivable to preload the friction lining in the axial direction by having the friction lining receptacle with a length that is smaller than the length of the friction lining.

[0020] If the through-opening is designed with a cross-section oriented perpendicular to the longitudinal axis, which is variable along the longitudinal axis, it is ensured that, depending on the tilting position of the friction lining carrier, a reliable contact of the friction lining on the tappet is ensured at least in sections.

[0021] Fastening elements on the friction damper according to claim 8 enable a direct fastening of the friction damper to parts that are movable relative to one another, in particular a washing tub and a housing of a washing machine.

[0022] An embodiment of the switching unit according to claim 9 enables a robust and direct locking of the friction lining carrier. In particular, a locking element serves for direct interaction with the friction lining carrier.

[0023] The switching unit has a switchable actuator, which is in particular a linear actuator and can be designed as a solenoid, spindle motor, pneumatic cylinder, or hydraulic cylinder. It is essential that the actuator can be dual-acting and, in particular, self-locking. This means that the actuator can be actively switched in both linear directions, i.e., can be displaced along these directions and, in particular, can hold the respective position. Alternatively, the actuator can be designed as a single-acting actuator, i.e., active in only one of the two linear directions.

[0024] An embodiment of the locking element according to claim 10 ensures efficient determination of the friction force. The locking element bears, in particular, directly against the friction lining carrier. The locking element can, in particular, be displaced into a spaced-apart arrangement with respect to the friction lining carrier. In this spaced-apart arrangement, the displaceability of the friction lining carrier is unhindered. If the locking element is arranged without contact with the friction lining carrier, the friction lining carrier is unlocked. In this arrangement of the locking element, the friction unit generates the direction-dependent friction force. For the locked arrangement, the locking element has a contact surface with which the locking element bears against a locking surface of the friction lining carrier.

[0025] An embodiment of the locking element according to claim 11 is uncomplicated and stable. In particular, the actuation of the locking element and / or the interaction of the locking element with the friction lining carrier is uncomplicated and mechanically robust.

[0026] A recess in the locking element according to claim 12 simplifies the locking of the friction lining carrier. The friction lining carrier can be arranged in and / or on the recess in the locking element. The locking element can be displaced collision-free along the longitudinal axis with respect to the friction lining carrier. Such a friction damper enables a compact and robust, in particular space-saving, construction. The recess is designed in particular as an opening, in particular as a through-opening. The recess and in particular the through-opening have a base area that is oriented in particular parallel to the longitudinal axis and parallel to the tilt axis. The recess, in particular the through-opening, extends on the locking element, in particular starting from an underside facing the friction lining carrier, along an extension direction oriented perpendicular to the base area.The direction of extension is oriented, in particular, perpendicular to the longitudinal axis and perpendicular to the tilt axis. It is also conceivable for the recess not to extend completely through the locking element. The recess can also extend from a side surface of the locking element, in particular along the tilt axis. It is particularly conceivable for recesses to be provided on both sides of the locking element, so that the friction lining carrier engages around the locking element in a tab-like manner and is guided past the locking element.

[0027] A fail-safe unit according to claim 13 ensures reliable and, in particular, damage-free and / or non-destructive operation of the friction damper in the event of an unintentional malfunction. Such a malfunction occurs in particular when the switchable actuator is inadvertently deactivated. For example, an actuator designed as a solenoid actuator may be inadvertently deactivated if the power supply is inadvertently interrupted, for example, in the event of a power failure. Switching the actuator is then no longer possible. The fail-safe unit ensures that, in this case, the locking element is moved to a position in which the friction damper has a maximum friction effect. This position is referred to as the maximum position.

[0028] The fail-safe unit comprises, in particular, at least one force storage element, in particular two or more force storage elements, which is designed, in particular, as a mechanical spring, in particular as a helical compression spring. The actuator is a single-acting solenoid. When energized, the solenoid is switched and moved into a position such that the locking element locks the friction lining carrier in a minimum position with minimal, direction-independent frictional force. The single-acting actuator can also be controlled such that one or more intermediate positions of the friction lining carrier are locked, in which a friction force greater than the minimum is present. One or more intermediate positions can be realized, for example, by controlling the actuator with a voltage proportional to the spring force, so that the friction lining carrier is held in the at least one intermediate position.Applying a voltage proportional to the spring force controls the magnet, which holds the friction lining carrier in the intermediate position. The actuator is operated to specifically set the variable friction force. When the actuator is deactivated, i.e. the power supply is stopped, the friction lining carrier is moved to its maximum position due to the spring force. In this case, the maximum friction force is effective. When the actuator is actuated with an increased voltage, the friction lining carrier is moved against the spring force to another intermediate position or to the minimum position, which depends on the voltage with which the actuator is controlled. In this intermediate or minimum position, a friction force acts that is reduced and, in particular, minimal compared to the maximum friction force. This makes it possible to specifically set a reduced, in particular minimal, friction force.

[0029] The locking element is moved into the minimum position counter to the spring force of at least one energy storage element. This imparts a counterforce to the energy storage element, which counteracts the movement and positioning of the locking element in the minimum position.

[0030] Due to the applied counterforce of the energy storage element, the locking element is moved from the minimum position or an intermediate position, in particular to the maximum position. In particular, the counterforce exerted by the energy storage element is dimensioned such that it reliably moves the locking element and the actuator back to the maximum position. In particular, the at least one energy storage element ensures reliable movement of the locking element with the actuator to the maximum position in the event of an unintentional power failure. The fail-safe unit ensures what is known as fail-safe operation of the friction damper. It is impossible for the friction damper to be inadvertently actuated with reduced and, in particular, minimal friction force in the event of a power failure. Damage and / or destruction to the components to be damped are excluded.

[0031] The actuator can have partial or complete self-holding. Due to partial or complete self-holding, energy consumption is reduced because the current supply to the actuator can be reduced or deactivated when the actuator with the locking element is in the minimum position or an intermediate position. With partial self-holding, the at least one energy storage element causes the return to the maximum position when the current supply is intentionally or unintentionally removed. In the case of complete self-holding, an additional electrical energy storage device serves to provide electrical energy for triggering the switching process to the maximum position. The electrical energy storage device can be implemented as one or more capacitors. The electrical energy storage device provides a current pulse for a switching process, which serves to release the self-holding of the actuator.As soon as the actuator leaves the self-holding position, i.e., the minimum position, its self-holding force also decreases significantly. The actuator's further movement back to the maximum position is achieved by the counterforce imprinted in the force-storing element, i.e., the mechanical spring. To ensure the "fail-safe function" with complete self-holding, a control device is provided that can provide the necessary current pulse for the switching process in the event of a power failure.

[0032] The control device has, in particular, at least one or more electrical components, in particular electromechanical components, in particular electromechanical switches, in particular relays, and / or electronic components, in particular electronic switching components, in particular transistors. When mains voltage is applied, the additional electrical energy storage device is electrically charged. The connection between the electrical energy storage device and the actuator is separated by means of the electrical component. In the event of a power failure, in particular an unintentional one, the electrical components ensure that the electrical energy storage device is separated from the charging device, in particular the mains voltage, and connected to the actuator. For this purpose, the electrical switching components are, in particular, designed such that they connect the electrical energy storage device to the actuator in the de-energized state.

[0033] Additionally or alternatively, it is also possible to use the electrical energy stored in the electrical energy storage device additionally for controlling the control device, in particular by means of transistors.

[0034] Both the features specified in the patent claims and the features specified in the following exemplary embodiments of the friction damper according to the invention are suitable, either individually or in combination with one another, for further developing the subject matter of the invention. The respective combinations of features do not represent any limitation with regard to further developments of the subject matter of the invention, but are essentially merely exemplary in nature.

[0035] Further features, advantages, and details of the invention will become apparent from the following description of two exemplary embodiments with reference to the drawings. They show: Fig. 1 a side view of a friction damper according to the invention, Fig. 2 a partially sectioned view according to section line II-II in Fig. 1 with unlocked friction lining carrier when actuated in the extension direction, Fig. 3 Fig. 2 corresponding illustration with unlocked friction lining carrier when the plunger is actuated in the insertion direction, Fig. 4 Fig. 2 corresponding representation with locked friction lining carrier in a minimum position with a minimum direction-independent friction force, Fig. 5 to 7 Fig. 2 corresponding representations with the friction lining carrier in different intermediate positions with different locking forces in the extension direction, whereby the friction lining carrier is unlocked in the insertion direction, Fig. 8a Fig. 2 corresponding representation with locked friction lining carrier in a maximum position at a maximum direction-independent friction force, Fig. 9 a perspective exploded view of friction unit and switching unit, Fig. 10 an enlarged perspective view of the friction lining carrier, Fig. 11 a sectional view according to section line XI-XI in Fig. 10 , Fig. 12 an enlarged perspective view of the locking element, Fig. 13 a sectional view according to section line XIII-XIII in Fig. 12 , Fig. 14a Fig. 9 corresponding representation of friction unit and switching unit of a friction damper according to a second embodiment, Fig. 15 a Fig. 4 corresponding representation of the friction damper according to Fig. 14 , Fig. 16a longitudinal section along section line XVI-XVI in Fig. 15 , Fig. 17a Fig. 16 corresponding representation in a maximum position of the friction lining carrier, Fig. 18 a sectional view according to section line XVIII-XVIII in Fig. 17 .

[0036] One in Fig. 1 bis 13 The friction damper, designated as a whole by 1, has a housing 2 with a longitudinal axis 3 and a plunger 4 which can be displaced along the longitudinal axis 3.

[0037] The housing 2 is constructed in several parts and comprises a tubular housing section 5 and a damping housing section 6 connected thereto. The tubular housing section 5 and the damping housing section 6 are arranged one behind the other along the longitudinal axis 3. The tubular housing section 5 and the connected damping housing section 6 together form the housing 2.

[0038] The tubular housing section 5 has, at least in sections, a tubular section whose inner contour corresponds to the outer contour of the tappet 4. The tubular section of the tubular housing section 5 serves to axially guide the tappet 4. According to the exemplary embodiment shown, the tubular section is designed as a cylindrical tube. Depending on the outer contour of the tappet 4, the inner contour of the tubular section can also be non-circular, in particular oval or polygonal, in particular square, hexagonal or octagonal. The tubular housing section 5 is oriented concentrically to the longitudinal axis 3. The tubular housing section 5 has an annular collar 7 which projects radially outwards with respect to the longitudinal axis 3. The annular collar 7 is in particular connected to the tubular section in one piece, in particular formed thereon in one piece. The annular collar 7 is in particular formed on the end face of the tubular housing section 5.The tubular housing section 5 is arranged in sections within the damping housing section 6, i.e., is partially enclosed by the damping housing section 6. At an exposed end opposite the annular collar 7, the tubular housing section 5 has a first fastening element 8 in the form of a fastening eyelet.

[0039] The damping housing section 6 is designed in several parts and comprises two housing half-shells 9, 10, which are particularly Fig. 9 The housing half-shells 9, 10 are detachably connected to each other with respect to a parting plane. The parting plane is perpendicular to the drawing plane according to Fig. 1 oriented and contains the longitudinal axis 3. The housing half-shells 9, 10 each have a recess 11 corresponding to the tubular housing section 5, in particular the tubular section and the annular collar 7, into which the tubular housing section 5 is inserted. The tubular housing section 5 is positively connected to the damping housing section 6. The tubular housing section 5 is fixed axially and radially to the damping housing section 6 with respect to the longitudinal axis 3.

[0040] The plunger 4 is tubular. The plunger 4 is a sliding tube. According to the exemplary embodiment shown, the plunger 4 is designed as a cylindrical tube. It is conceivable for the plunger 4 to be a tube with a deviating outer contour, in particular a non-circular outer contour such as an oval or polygonal, in particular square, hexagonal, or octagonal, outer contour. It is essential that the outer contour of the plunger 4 is constant along the longitudinal axis 3. With its first end 12, which has an insertion bevel 13, the plunger 4 is arranged in the housing 2, in particular in the tubular housing section 5.

[0041] At a second end 14 opposite the first end 12, the plunger 4 has a second fastening element 15, which is designed as a fastening eye. The second fastening element 15 is inserted, in particular, with a connecting portion at the end face into the sliding tube of the plunger 4 and secured therein. According to the illustrated embodiment, the sliding tube of the plunger 4 is connected to the fastening portion of the second fastening element 15 by compression molding. Other joining methods such as gluing or welding are also possible.

[0042] The second end 14 of the plunger 4 with the second fastening element 15 is arranged outside the housing 2.

[0043] The friction damper 1 can be hinged to mutually movable parts to be damped by the fastening elements 8, 15. For example, the fastening elements 8, 15 for damping oscillations of a washing machine are connected to the housing of the washing machine on the one hand and to the washing machine's tub on the other.

[0044] The housing 2 has a housing opening 16 through which the plunger 4 is guided into the housing 2, in particular through the damping housing section 6 into the tubular housing section 5.

[0045] The friction damper 1 has a friction unit 17 which is Fig. 10 und 11 is shown in detail. The friction unit 17 comprises a friction lining carrier 18, on which two identical, half-shell-shaped friction linings 19 are held. The friction linings 19 are each arranged in a friction lining receptacle 20, which is designed as a recess in an inner surface of a through-opening 21 of the friction lining carrier 18.

[0046] The friction lining carrier 18 is designed like a piston.

[0047] In the assembled state of the friction damper 1, the plunger 4 is guided through the through opening 21.

[0048] The through-opening 21 is designed to be asymmetrical, at least in sections, in a plane perpendicular to the longitudinal axis. The through-opening 21 has a first through-opening section 22 with a first section longitudinal axis 23 and a second through-opening section 24 with a second section longitudinal axis 25.

[0049] In particular, the friction lining recesses 20 are each arranged as groove-shaped depressions in the region of the first through-opening sections 22. The first through-opening sections 22 extend in the circumferential direction with respect to the longitudinal axis 3 along 180°. A first through-opening section 22 and a second through-opening section 24 together form the closed through-opening 21. Since the first section longitudinal axis 23 is arranged at an inclination angle n relative to the second section longitudinal axis 25, the contour of the inner surface of the through-opening 21, which is formed by the partial contours of the first through-opening section 22 and the second through-opening section 24, is non-circular. According to the exemplary embodiment shown, the inclination angle is approximately 15°. In particular: 0° < n < 45°, in particular 5° < n < 30°, in particular 10° < n < 20°.

[0050] A first through-opening section 21 and a second through-opening section 24 are arranged one behind the other along the longitudinal axis 3.

[0051] The friction lining carrier 18 has a pivot opening 26 through which a connecting element 27 in the form of a tilt pin is guided for the pivotable arrangement of the friction lining carrier 18 in the housing 2. The connecting element 27 is held on the end face in a corresponding receptacle 28 on an inner side of the housing half-shells 9, 10. The connecting element 27 defines a tilt axis 29 about which the friction lining carrier 18 can be tilted on the connecting element 27 and thus relative to the housing 2. The tilt axis 29 is oriented perpendicular to the longitudinal axis 3 of the housing 2. The tilt axis 29 is oriented at a distance from the longitudinal axis 3. The tilt axis 29 and the longitudinal axis 3 do not intersect. The spatial relationship between the tilt axis 29 and the longitudinal axis 3 is referred to as skew. The tilt axis 29 is oriented in particular perpendicular to the parting plane of the housing half-shells 9, 10.The pivot opening 26 is arranged at a distance from the through opening 21 on the friction lining carrier 18.

[0052] The friction lining carrier 18 comprises a first stop surface 31 and a second stop surface 32. The first stop surface 31 and the second stop surface 32 are arranged opposite one another along the longitudinal axis 3 relative to the pivot opening 26. The first stop surface 31 and the second stop surface 32 are each arranged on an outer side of the friction lining carrier 18.

[0053] The friction lining carrier 18 has a first locking surface 33 and a second locking surface 34. Furthermore, the friction lining carrier 18 has a third locking surface 35, a fourth locking surface 36, and a fifth locking surface 37. The locking surfaces 34, 35, 36, and 37 are designed in a stepped manner and adjacent to one another on an outer side of the friction lining carrier 18. The locking surfaces 34, 35, 36, and 37 directly adjoin one another.

[0054] For the tiltable arrangement of the friction lining carrier 18 in the housing 2, the housing half-shells 9, 10 each have a friction lining carrier recess 38, which essentially corresponds to the outer contour of the friction lining carrier 18, but allows the friction lining carrier 18 to be tilted in the housing 2 about the tilt axis 29. The friction lining carrier recess 38 has counter surfaces 39 and 40 corresponding to the stop surfaces 31 and 32.

[0055] The friction damper 1 further comprises a switching unit 41. The switching unit 41 comprises a switchable actuator 42, which is designed as a linear actuator. For actuating the electrically switchable actuator 42, it has a connecting cable 57. The actuator 42 has an actuating element 43, which can be displaced along an actuating direction 44. The actuating direction 44 is oriented parallel to the longitudinal axis 3. The actuator 42 can be designed, for example, as a lifting magnet, spindle motor, pneumatic cylinder, or hydraulic cylinder. The actuator 42 is designed to be dual-acting, i.e., it can be actively displaced along the insertion direction 58 and along the extension direction 58. The actuator 42 is designed to be self-locking. The actuator 42 is reliably held in the respectively controlled position.

[0056] The switching unit 41 has a locking element 45 that is mechanically coupled to the actuator 42, in particular to the adjusting element 43. The actuator 42 serves to linearly displace the locking element 45 along the adjusting direction 44.

[0057] The locking element 45, which in Fig. 12 und 13 shown in detail, has a pin-shaped connecting section 46, which serves for connection to the adjusting element 43. For this purpose, a transverse bore 47 is provided in the connecting section 46, through which a connecting bolt 48 is guided for connection to the adjusting element 43.

[0058] The locking element 45 is designed as a slide. The locking element 45 is essentially strip-like, with the strip extending along the adjustment direction 44. The locking element has a recess 49 designed as an opening through which the friction lining carrier 18 is guided in the assembled arrangement of the friction damper 1. Due to the opening 49, the locking element 45 is designed like a frame.

[0059] The locking element 45 has, on the side webs 50 which delimit the opening 49 and are oriented parallel to the adjustment direction 44, a groove-shaped recess 51 in each case, in which the connecting element 27 is arranged.

[0060] The locking element 45 has a rear transverse web 52 facing the connecting section 46 and a front transverse web 53 facing away from the connecting section 46. The transverse webs 52, 53 delimit the opening 49 in the direction of the adjustment direction 44. The transverse webs 52, 53 each connect the oppositely arranged side webs 50.

[0061] A first contact surface 54 is formed on the rear transverse web 52 on its underside and adjacent to the opening 49.

[0062] The front crosspiece 53 has a substantially wedge-shaped contour that tapers toward the rear crosspiece 52. The front crosspiece 53 has a second contact surface 55. The second contact surface 55 forms the underside, which is inclined relative to the upper side 56 of the front crosspiece 53.

[0063] The following is based on particular Fig. 2 bis 8 the function of the friction damper 1 is explained in more detail. According to Fig. 2 In the friction damper 1, the switching unit 41 is switched such that the displacement of the friction lining carrier 18 is unblocked. The friction lining carrier 18 can tilt about the tilt axis 29 depending on the direction of displacement of the plunger 4. In particular, the locking element 45 is arranged such that the friction lining carrier 18 can be tilted contactlessly in the housing 2 with respect to the locking element 45. In the aforementioned switching position of the switching unit 41, the friction lining carrier 18 is unlocked.

[0064] If the plunger 4 is displaced, as in Fig. 2 shown, along a pull-out direction 58, the outer contour of the tappet 4 rubs against the friction linings 19. As a result of the friction force transmission from the tappet 4 to the friction linings 19 and the friction lining carrier 18, a torque acts on the friction lining carrier 18, which according to Fig. 2 oriented counterclockwise to the tilt axis 29. Based on the arrangement in Fig. 2 further tilting of the friction lining carrier 18 is prevented because the friction lining carrier 18 rests with the first stop surface 31 on the corresponding first counter surface 39 of the housing 2.

[0065] In the Fig. 2 In the arrangement shown, the friction lining carrier 18 is in an extended position. In the extended position, the friction lining carrier 18 is tilted about the tilt axis 29 at a first tilt angle k 1. Because the contact area and the surface pressure of the friction linings 19 with the tappet 4 are minimal, the friction effect caused in the extension direction 58, the so-called extension friction, is also minimal.

[0066] When the friction damper 1 is actuated in the insertion direction 59, as shown in Fig. 3 shown, and when the friction lining carrier 18 is unlocked, the friction lining carrier 18 is rotated clockwise around the tilting axis 29 according to Fig. 3 pivoted until the friction lining carrier 18 rests with the second stop surface 32 against the corresponding second counter surface 40 of the housing 2. In this arrangement, which is also referred to as the insertion position, the friction effect against the insertion direction 59 is maximum, since the friction linings 19 rest against the outside of the tappet 4 with maximum contact area and maximum surface pressure. The insertion friction is greater than the extension friction.

[0067] In the Fig. 3 In the insertion position shown, the friction lining carrier 18 is tilted relative to the tilt axis 29 at a second tilt angle k 2 . According to the embodiment shown, the second tilt angle k 2 is 0°.

[0068] In particular, the difference between the first tilt angle k 1 and the second tilt angle k 2 results from the inclination angle n, which is determined by the section longitudinal axes 23, 25.

[0069] The Fig. 2 and 3The functionality of the friction damper 1 shown with the unlocked friction lining carrier 18 essentially corresponds to that of the friction damper according to EP 3 296 587 A1, to which reference is hereby expressly made. In addition, the friction damper 1 has another function.

[0070] The function of the switching unit 41 and the interaction with the friction unit 17, in particular the friction lining carrier 18, is explained below using the Fig. 4 bis 8 explained in more detail.

[0071] Starting from Fig. 2 , in which a minimal friction force is exerted on the plunger 4 by the friction unit 17, the locking element 45 is displaced into a first locking position, which in Fig. 4 For this purpose, the locking element 45 is moved from the arrangement in Fig. 2 along the adjustment direction 44 to the right, i.e., away from the actuator 42. The displacement occurs until the locking element 45 rests with the first contact surface 54 against the first locking surface 33 of the friction lining carrier 18. In this switching position, the friction damper 1 has a minimal frictional force, namely the insertion friction, and minimal surface pressure, even when the plunger 4 is displaced in the insertion direction 59. The friction lining carrier is in the minimum position. Tilting of the friction lining carrier 18 about the tilt axis 29 in a clockwise direction is blocked by the locking element 45. When the plunger 4 is displaced in the extension direction 58, tilting of the friction lining carrier 18 about the tilting axis 29 in the counterclockwise direction is blocked by the friction lining carrier 18 resting with the first stop surface 31 on the corresponding counter surface 39.

[0072] Accordingly, starting from the arrangement of the friction lining carrier 18 in the inserted position, i.e., at maximum friction force, it is possible to block the friction lining carrier 18 by displacing the locking element 45 to the left, i.e., toward the actuator 42, along the adjustment direction 44. In this arrangement, the friction lining carrier 18 rests with the second locking surface 34 against the second contact surface 55.

[0073] In order to block the friction lining carrier 18 in the inserted position, i.e. at maximum frictional force, a lifting movement of the locking element 45 along the actuating direction 44 is required. It has been recognized that it is advantageous if additional intermediate switching positions can be defined which ensure different friction conditions. In the various intermediate switching positions, the friction damper has a frictional force of different magnitudes. In particular, in the intermediate switching positions, a pivoting movement of the friction lining carrier 18 upon actuation of the plunger 4 in the extension direction 58 is blocked by the locking element 45. The magnitude of the frictional force is fixed in the extension direction 58. When the plunger 4 is actuated in the insertion direction 59, a pivoting movement of the friction lining carrier 18 is possible, in particular such that the frictional force is increased upon actuation of the plunger 4 in the insertion direction 59.

[0074] According to the Fig. 5 In the switching position of a first locking stage shown, the locking element 45 is arranged with the second contact surface 55 on the third locking surface 35. In this arrangement, the third tilt angle k 3 is 10.5°. According to Fig. 5 The friction lining carrier 18 is in a first intermediate position, which represents a first intermediate switching position. In the first intermediate position, a pivoting movement of the friction lining carrier 18 about the tilt axis 29 in a counterclockwise direction, i.e., when the plunger 4 is actuated in the extension direction 58, is blocked by the locking element 45. When the plunger 4 is actuated in the insertion direction, the friction force caused by the friction linings 19 exerts a torque on the friction lining carrier 19 about the tilt axis 29 in a clockwise direction. Tilting of the friction lining carrier 18 about the tilt axis 29 in a clockwise direction is possible.

[0075] Accordingly, in the switching position according to Fig. 6 In the second locking stage, the locking element 45 is arranged with the second contact surface 55 on the fourth locking surface 36. In this arrangement, the fourth tilt angle k 4 is 7°. According to Fig. 6 the friction lining carrier 18 is in a second intermediate position, which represents a second intermediate switching position. In the second intermediate position, a pivoting movement of the friction lining carrier 18 about the tilting axis 29 in the counterclockwise direction, i.e. upon actuation of the plunger 4 in the extension direction 58, is blocked by the locking element 45. Upon actuation of the plunger 4 in the insertion direction 59, the friction force caused by the friction linings 19 causes a torque on the friction lining carrier 19 about the tilting axis 29 in the clockwise direction. Tilting of the friction lining carrier 18 about the tilting axis 29 in the clockwise direction is possible. In the switching position according to Fig. 7 In a third locking stage, the locking element 45 is arranged with the second contact surface 55 on the fifth locking surface 37 of the friction lining carrier 18. In this arrangement, the fifth tilt angle k 5 is 3.5°. According to Fig. 7 The friction lining carrier 18 is in a third intermediate position, which represents a third intermediate switching position. In the third intermediate position, a pivoting movement of the friction lining carrier 18 about the tilt axis 29 in a counterclockwise direction, i.e., when the plunger 4 is actuated in the extension direction 58, is blocked by the locking element 45. When the plunger 4 is actuated in the insertion direction 59, the friction force caused by the friction linings 19 exerts a torque on the friction lining carrier 18 about the tilt axis 29 in a clockwise direction. Tilting of the friction lining carrier 18 about the tilt axis 29 in a clockwise direction is possible.

[0076] In the order pursuant to Fig. 8 The friction damper 1 exhibits a maximum, direction-independent friction force. The friction lining carrier 18 rests with the second stop surface 32 against the counter surface 40. Actuation of the plunger 4 in the insertion direction 59 does not cause the friction lining carrier 18 to tilt clockwise about the tilt axis 29. Tilting of the friction lining carrier 18 about the tilt axis 29 in the counterclockwise direction upon actuation of the plunger in the extension direction is blocked by the locking element 45.

[0077] According to the embodiment shown, between the switching position in the pull-out position with minimal friction force in the insertion direction 59 according to Fig. 4 and in insertion position with maximum friction force in insertion direction 59 according to Fig. 8 three intermediate stages are provided, in which the tilt angles k 3 , k 4 and k 5 are each arranged at the same distance from one another and in particular from the first tilt angle k 1 and the second tilt angle k 2 .

[0078] It is possible to provide more or fewer intermediate stages, or even none at all. It is particularly conceivable that the distances between the individual intermediate stages and / or between the switching stages of maximum and minimum friction force could be set differently.

[0079] It was found that the switching positions with the intermediate stages according to the first to third locking stage make it easier for the friction damper 1 to carry out the switching process of the locking element 45 into the position of the maximum friction force even with smaller amplitudes of the plunger 4.

[0080] In the following, with reference to Fig. 14 bis 18 Describe a second embodiment of the invention. Structurally identical parts are given the same reference numerals as in the first embodiment, to the description of which reference is hereby made. Structurally different but functionally similar parts are given the same reference numerals with an a suffix.

[0081] A significant difference between the friction damper 1a and the previous embodiment is that the actuator 42a is designed to be single-acting. The actuator 42a can be actuated along the actuating direction 44 in a direction that is directed from the actuator 42a to the locking element 45a. This direction is Fig. 15 bis 18 oriented from left to right. Actuator 42a cannot be switched in the opposite direction.

[0082] The friction damper 1a also has a fail-safe unit, which, according to the exemplary embodiment shown, has two force storage elements 60. Each force storage element 60 is designed as a helical compression spring according to the exemplary embodiment shown. More or fewer than two force storage elements 60 can also be provided. The force storage elements 60 are arranged laterally in the housing 2a next to the locking element 45 and are each supported in the housing 2a on a contact shoulder 61 fixed to the housing axially along the actuating direction 44. The contact shoulder 61 is oriented in the housing 2a in such a way that displacement of the force storage elements 60 in the actuating direction of the actuator 42a, i.e., from the actuator 42a to the locking element 45a, is prevented.

[0083] The locking element 45a has laterally projecting, integrally formed pressure plates 62. The pressure plates 62 serve to directly engage the respective force storage element 60. Each force storage element 60 is arranged along the adjustment direction 44, i.e., between a pressure plate 62 of the locking element 45a and the contact shoulder 61 of the housing 2a.

[0084] A receiving element 63 is arranged on each of the pressure plates 62 and the oppositely arranged contact shoulders 61. The receiving element 63 serves to receive, guide, and hold the force storage element 60. The receiving elements 63 are essentially identical. The receiving elements 63 are essentially cylindrical or slightly conical. The receiving elements 63 are designed such that they can be arranged within the hollow cylinder formed by the force storage element 60. The outer diameter of the respective receiving element 63 is smaller, and in particular slightly smaller, than the inner diameter of the force storage element 60. The outer diameter of the receiving element 63 can also essentially correspond to the inner diameter of the force storage element 60.

[0085] The receiving element 63 extends in the axial direction of the longitudinal axis 3.

[0086] The following is based on Fig. 14 bis 18 the function of the friction damper 1a is explained in more detail.

[0087] To insert the friction damper 1a into the Fig. 15 and 16 To transfer the arrangement shown, the actuator 42a is switched, i.e. energized. To trigger this switching process, the actuator 42, which is designed as a solenoid, is overdriven, in particular driven with four times the nominal voltage. This causes the actuating element 43 to move according to Fig. 15 and 16 from left to right into the Fig. 17 and 18 shown position. With the actuating element 43, the locking element 45a attached to it is instantly displaced. The locking element 45a rests against the first locking surface 33 of the friction lining carrier 18a and locks the friction lining carrier 18a in a minimum position. In the minimum position of the friction lining carrier 18a, the friction linings 19 are arranged with minimal contact with the tappet 4 of the friction damper 1a. The minimum position is in Fig. 15 and 16 shown.

[0088] After the switching process has been completed, the voltage can be reduced to the nominal voltage. The force provided by the solenoid 42a is sufficient to hold the locking element 45a in the minimum position. This holding force is necessary because the energy storage elements 60 have been compressed by moving the locking element 45a to the minimum position, thus imposing a mechanical force on the energy storage elements. This counterforce counteracts the holding force of the actuator 42a.

[0089] To return the actuator 42a to the maximum position according to Fig. 17 and 18 the current supply to the actuator 42a is switched off. Due to the counterforce of the energy storage elements 60, the locking element 45a is moved in the direction of the actuator 42a, i.e. according to Fig. 15 and 16from right to left. This is caused by the pressure force exerted by the force storage elements 60 on the pressure plates 62.

[0090] Because this shift back from the maximum position according to Fig. 17 and 18 to the minimum position according to Fig. 15 and 16 When the actuator 42a is not energized, the energy storage elements 60 form the fail-safe unit for the friction damper 1a. This ensures that in the event of an unintentional power failure, the friction damper 1a is reliably transferred to a state in which maximum friction damping is guaranteed.

[0091] The actuator 42a according to the illustrated embodiment does not have a self-locking mechanism. This means that the actuator 42a can displace the actuating element 43 with the locking element 45a essentially frictionlessly along the actuating direction 44.

[0092] Alternatively, it is conceivable to design the actuator 42a as a lifting magnet with partial self-locking. One advantage is that the voltage required to hold the actuator 42a in the Fig. 15 The force required to maintain the minimum position shown is reduced compared to the actuator 42a without self-locking. This reduces energy consumption. In particular, the force storage elements 60 are dimensioned such that the impressed counterforce of the force storage elements 60 is greater than the self-locking of the magnet. In the event of a power failure or when the power supply to the actuator 42a is switched off, the locking element 45a is reliably returned to the maximum position.

[0093] Alternatively, it is also possible to design the actuator 42a with complete self-holding. In this case, the holding force of the actuator 42a in the minimum position is Fig. 15so strong that after the switching operation with override, the power supply can be switched off. This further reduces energy savings. To return the actuator 42a to the maximum position, it must be energized in the opposite direction. Since the self-holding function quickly diminishes, a brief energization in the form of a short current pulse is sufficient to release the self-holding function, with the energy storage elements 60 then completely returning the locking element 45a to the maximum position. To ensure that the locking element 45a is returned to the maximum position even in the event of a power failure, thus enabling a so-called "fail-safe function," the switching unit 41 is signal-connected to an electrical storage element (not shown). The electrical storage element is operatively connected to the actuator 42a.The electrical storage element is formed in particular by one or more capacitors which provide the electrical supply for a short current pulse to release the self-holding in the event of a power failure.

Claims

1. Friction damper comprising a. a housing (2) having a longitudinal axis (3), b. a plunger (4) that can be displaced along the longitudinal axis (3), c. a friction unit (17) for producing a direction-dependent frictional force on the plunger (4), wherein the friction unit (17) comprises at least one friction lining (19) that is in frictional contact with the plunger (4), d. a switching unit (41) for variable setting of the frictional force, wherein the friction unit (17) comprises a friction lining support (18), on which the at least one friction lining (19) is held, characterised in that - the friction lining support (18) is arranged so as to be displaceable relative to the plunger (4) between a pull-out position and an insertion position, - the friction lining support (18) is arranged in the housing (2) so as to be pivotable about a pivot axis (29), wherein the pivot axis (19) is arranged transverse to the longitudinal axis (3).

2. Friction damper according to one of the preceding claims, characterised in that the friction lining support (18) has at least one friction lining receptacle (20), in which the at least one friction lining (19) is arranged.

3. Friction damper according to one of the preceding claims, characterised by two friction linings (19), which in particular respectively have a half-shell contour.

4. Friction damper according to one of the preceding claims, characterised in that the friction lining support (18) has a passage opening (21) through which the plunger (4) is guided.

5. Friction damper according to claim 4, characterised in that the passage opening (21) has a contour that is at least partially asymmetrical perpendicular to the longitudinal axis (3).

6. Friction damper according to claim 4 or 5, characterised in that the passage opening (21) has a first passage opening section (22) and a second passage opening section (24), wherein in particular the first passage opening section (22) and the second passage opening section (24) respectively have a section longitudinal axis (23, 25), which are arranged inclined to each other at an angle of inclination (n).

7. Friction damper according to one of claims 4 to 6, characterised in that the friction lining receptacle (20) is designed as a recess in the passage opening (21).

8. Friction damper according to one of the preceding claims, characterised in that the friction damper (1) has a first fastening element (8) arranged in particular on the housing (2) and a second fastening element (15) arranged in particular on the plunger (4) for fastening to moving parts.

9. Friction damper according to one of the preceding claims, characterised in that the switching unit (41) has a switchable actuator (42) and a locking element (45) mechanically coupled to the actuator (42).

10. Friction damper according to claim 9, characterised in that the locking element (45) has at least one contact surface (54, 55) with which the locking element (45) rests against at least one locking surface (33, 34, 35, 36, 37) of the friction lining support (18) in a locked arrangement.

11. Friction damper according to claim 9 or 10, characterised in that the locking element (45) is designed as a sliding element that can be moved linearly, in particular perpendicular to the pivot axis (29).

12. Friction damper according to one of claims 9 to 11, characterised in that the locking element (45) has a cut-out (49) for collision-free displacement of the locking element (45) along the longitudinal axis (3).

13. Friction damper according to one of claims 9 to 12, characterised by a fail-safe unit for a fail-safe function of the friction damper for arranging the locking element (45, 45a) in a locked arrangement on the friction lining support (18, 18a) in such a way that a maximum direction-dependent frictional force is applied.