CONNECTING TREES

Abstract

Shaft connection (1) comprising a first shaft (5) rotatable about an axis of rotation (3), a second shaft (7) arranged coaxially to the first shaft (5) and axially movable relative to the first shaft (5), and at least one pair of spring elements (9) each comprising a first spring element (11) and a second spring element (13), wherein the first spring element (11) and the second spring element (13) are each attached to the first shaft (5) and to the second shaft (7), and wherein the first spring element (11) and the second spring element (13) are arranged axially offset from each other.

Description

Field of the invention

[0001] The disclosure relates to a shaft connection, a coupling and a use of a shaft connection or a coupling. State of the art

[0002] Shaft connections or couplings are known from the prior art, in which two shafts are connected via a spring. The spring can exert a restoring force in the axial direction on one of the two shafts relative to the other of the two shafts. For example, WO 2020 / 128403 A1 discloses a force-generating device for an aircraft control stick, in which an actuator can be moved by an electromagnet, and in which a spring exerts a restoring force on the actuator.

[0003] However, shaft connections or couplings known from the prior art have restrictions, in particular with regard to the torsional rigidity of shaft connections or with regard to the axial lifting force provided by the shaft connection. Disclosure of the invention

[0004] The object of the disclosure is to provide a shaft connection, a coupling, and a use of a shaft connection or a coupling that are improved over the prior art. In particular, a shaft connection should be provided that has high torsional rigidity or requires a low axial lifting force.

[0005] The object is achieved with a shaft connection according to claim 1 and a coupling and a use according to the independent claims.

[0006] According to one aspect, a shaft connection is provided. The shaft connection comprises a first shaft rotatable about a rotational axis, a second shaft arranged coaxially to the first shaft and axially movable relative to the first shaft, and at least one pair of spring elements, each having a first spring element and a second spring element. The first spring element and the second spring element are each fastened to the first shaft and the second shaft, and the first spring element and the second spring element are arranged axially offset from one another.

[0007] According to a further aspect, a coupling is provided. The coupling comprises a shaft connection according to one of the embodiments described herein, and a rotor shaft arranged coaxially with the first shaft and the second shaft. The coupling is configured to couple the first shaft and the second shaft to the rotor shaft, thereby moving the second shaft axially toward the rotor shaft.

[0008] According to yet another aspect, a use of a shaft connection according to any of the embodiments described herein or a coupling according to any of the embodiments described herein is provided, with moving the second shaft relative to the first shaft in an axial direction.

[0009] In typical embodiments, the shaft connection comprises a first shaft. Typically, the first shaft of the shaft connection is rotatable about a rotational axis. The terms "axial," "coaxial," "radial," and "in the circumferential direction" refer here in particular to the rotational axis. An axial direction is to be understood in particular as a direction of the rotational axis. Typically, the shaft connection comprises a second shaft. In typical embodiments, the first shaft and the second shaft are arranged coaxially. In typical embodiments, the first shaft is an output shaft. The second shaft is typically a drive shaft. In further typical embodiments, the first shaft can be a drive shaft and the second shaft an output shaft. In typical embodiments, the first shaft or the second shaft is designed as a hollow shaft, in particular annular.In other typical embodiments, the first shaft or the second shaft is designed as a solid shaft. Typically, the first shaft and the second shaft are made of metal.

[0010] In typical embodiments, the shaft connection comprises at least one pair of spring elements. Typically, a first spring element and a second spring element form a pair of spring elements. In embodiments, the first spring element and the second spring element are identical. Typically, the first shaft and the second shaft are connected to one another via the at least one pair of spring elements, in particular, they are connected in a rotationally fixed manner.

[0011] Typically, the first spring element and the second spring element of a spring element pair are each fastened to the first shaft and the second shaft, in particular via force-locking or form-locking fastening means such as screws or rivets. In embodiments, the first shaft and the second shaft can have stepped flat surfaces for fastening the at least one pair of spring elements.

[0012] Typically, the first spring element and the second spring element of the at least one spring element pair are arranged axially offset from one another. In particular, the first spring element and the second spring element are arranged axially spaced from one another. An axial distance between a spring element of a spring element pair and the first shaft or the second shaft can be provided, for example, by an axial spacer which is arranged at the fastening position of the spring element between the spring element and the first shaft or the second shaft. Spacers can be formed as part of fastening means for fastening the spring elements to the first shaft and to the second shaft. An axial distance between the spring elements of a spring element pair can be provided by different distances of the spring elements from the first shaft or the second shaft.Different axial distances of the spring elements to the first shaft or the second shaft can be provided, for example, by using different spacers at the fastening positions of the spring elements.

[0013] In typical embodiments, the first spring element is configured to be subjected to tensile stress in a first direction of rotation of the first shaft and the second shaft. Typically, the second spring element is configured to be subjected to tensile stress in a second direction of rotation of the first shaft and the second shaft, which is different from the first direction of rotation. In embodiments, at least one pair of spring elements can be arranged in particular such that, when the first shaft and the second shaft rotate, one spring element of the pair of spring elements is always subjected to tensile stress, regardless of the direction of rotation, while the other spring element of the pair of spring elements is subjected to compressive stress. Embodiments can, in particular, have high torsional rigidity in both directions of rotation about the axis of rotation. For example, high torsional rigidity can be achieved without making a spring element particularly solid to prevent buckling under compressive loads.

[0014] Typically, the second shaft is axially movable relative to the first shaft. Typically, the mobility of the second shaft relative to the first shaft is limited in the axial direction. Typically, the mobility of the second shaft axially in the direction of the first shaft is limited by a stop of the first shaft or by a maximum deflection position of the at least one pair of spring elements in the direction of the first shaft. Typically, the mobility of the second shaft in the axial direction away from the first shaft is limited by the at least one pair of spring elements.Typically, the maximum axial deflection away from the first shaft of the second shaft relative to the first shaft is limited or predetermined by an axial distance between the first spring element and the second spring element, wherein the axial distance between the first spring element and the second spring element refers to the axial distance in a non-deflected state of the first spring element and the second spring element.

[0015] In typical embodiments, the first spring element and the second spring element are each designed as a leaf spring. Typically, a leaf spring has two parallel, flat sides. A thickness of the leaf spring, measured between the two flat sides, is typically smaller than a length or a width of the leaf spring, in particular at least five times or at least ten times smaller. Typically, a leaf spring is elongated. For example, the length of the leaf spring can be at least twice the width of the leaf spring, in particular at least three times or at least four times. In typical embodiments, a leaf spring is made of metal, in particular of spring steel sheet.

[0016] Typically, a respective leaf spring of the first spring element or of the second spring element is aligned at least substantially parallel to a plane orthogonal to the rotation axis or a flat surface of the first shaft or of the second shaft, particularly when the leaf spring is not deflected from the rest position of the leaf spring. Typically, the flat sides of the leaf spring are aligned at least substantially parallel to a plane orthogonal to the rotation axis. An at least substantially parallel alignment is understood to mean, in particular, a deviation of a maximum of 10 degrees, in particular of a maximum of 5 degrees or a maximum of 2 degrees.

[0017] According to typical embodiments, a respective leaf spring of the first spring element or of the second spring element is arc-shaped, in particular circular arc-shaped or banana-shaped. The leaf spring can, for example, be designed essentially in the form of a circular ring cutout. Typically, the leaf spring is arc-shaped along a longitudinal direction of the leaf spring. Typically, the leaf spring is arranged in the shaft connection with a radially outward curvature. In embodiments, the leaf spring extends essentially in the circumferential direction around the axis of rotation. In embodiments, an arc center point of an arc-shaped leaf spring lies radially within the radially innermost fastening position of the at least one spring element pair.With curved spring elements, for example, a larger inner diameter of the first shaft or the second shaft can be provided when the first shaft or the second shaft is designed as a hollow shaft. In other typical embodiments, a respective leaf spring of the first spring element or the second spring element is designed straight. A straight design can provide greater rotational stiffness of the leaf spring.

[0018] In typical embodiments, the first spring element and the second spring element of a spring element pair are arranged in a crossed manner. In particular, the first spring element and the second spring element cross each other when viewed along the axis of rotation. The first spring element and the second spring element can cross each other symmetrically. The crossed arrangement of the spring elements can provide high rigidity independent of the direction of rotation. In embodiments, the first spring element is fastened to the first shaft at a first fastening position and to the second shaft at a second fastening position provided radially inside the first fastening position. Typically, the second spring element is fastened to the first shaft at a third fastening position and to the second shaft at a fourth fastening position provided radially inside the third fastening position.Typically, the third fastening position is arranged offset from the first fastening position by a first angle in a first circumferential direction. Typically, the fourth fastening position is arranged offset from the second fastening position by a second angle in a second circumferential direction different from the first circumferential direction.

[0019] In typical embodiments, the first spring element and the second spring element each extend over the same angular range around the axis of rotation. Typically, the angular range comprises at least 60 degrees, in particular at least 70 degrees, or a maximum of 130 degrees, in particular a maximum of 120 degrees. In particular, the angular range can comprise at least 70 degrees and a maximum of 120 degrees, for example approximately 90 degrees. A long spring length of the spring elements can, for example, provide a low restoring force of the spring elements. A low restoring force can provide a soft axial connection between the first shaft and the second shaft, so that in particular a lifting device configured to move the second shaft axially requires only a low lifting force to overcome the restoring force.Typically, the first fastening position of the first spring element and the fourth fastening position of the second spring element are arranged at a first angular position relative to the rotation axis. Typically, the second fastening position of the first spring element and the third fastening position of the second spring element are arranged at a second angular position different from the first angular position. Typically, the first angular position and the second angular position include one of the angular ranges described herein.

[0020] According to typical embodiments, the first spring element and the second spring element each have a fastening position on a first circle around the axis of rotation on the first shaft. Typically, the first spring element and the second spring element each have a further fastening position on a second circle around the axis of rotation on the second shaft. The fastening position and the further fastening position of a spring element are typically located at opposite ends of the spring element. Typically, the first circle and the second circle have different radii. For example, in embodiments, the first circle has a larger radius than the second circle. In particular, the first fastening position of the first spring element and the third fastening position of the second spring element can be provided on the first circle around the axis of rotation.The second fastening position of the first spring element and the fourth fastening position of the second spring element can be provided on the second circle around the rotation axis. In further typical embodiments, the first circle can have a smaller radius than the second circle.

[0021] In typical embodiments, the shaft connection comprises at least two pairs of spring elements, in particular at least three pairs of spring elements. For example, the shaft connection can comprise exactly two, exactly three, or exactly four pairs of spring elements. The number of pairs of spring elements can be selected, for example, depending on the axial stroke to be provided by the second shaft or the torque to be transmitted. In one exemplary embodiment, the shaft connection has exactly three pairs of spring elements. In particular, a large axial stroke can be achieved and a high torque can be transmitted.

[0022] In typical embodiments with more than one spring element pair, each spring element pair comprises a first spring element and a second spring element, in particular a first spring element and a second spring element according to embodiments described herein. Typically, all first spring elements of the shaft connection are identical. Typically, all second spring elements of the shaft connection are identical. In particular, all first spring elements and all second spring elements can be identical. In embodiments, the at least two spring element pairs are arranged distributed in the circumferential direction around the axis of rotation, in particular arranged uniformly distributed in the circumferential direction. Typically, the at least two spring element pairs are arranged separately from one another in the circumferential direction, in particular without an overlap of the spring element pairs in the circumferential direction.

[0023] According to embodiments, the first shaft and the second shaft are arranged one behind the other in an axial direction. In embodiments, a radial extension of the first shaft and a radial extension of the second shaft can each comprise an overlapping, radial region. The first shaft and the second shaft can be arranged axially one behind the other in the overlapping, radial region. The first spring element and the second spring element can be fastened to the first shaft or to the second shaft in the overlapping, radial region. In particular, the fastening positions of the first spring element and the second spring element on the first shaft and on the second shaft can be provided in the overlapping, radial region.

[0024] Typically, the second shaft is movable in the axial direction relative to the first shaft. Typically, the second shaft is movable in the axial direction relative to the first shaft at least between two axial positions, in particular between a first axial position and a second axial position. The first axial position can be an axial position close to the first shaft, in particular at an axial stop of the housing or the first shaft, or a rest position in which the at least one pair of spring elements is in an axially unloaded state with respect to the first shaft. The second axial position is typically further away from the first shaft than the first axial position.

[0025] Typically, the second shaft is movable in the axial direction under the action of a spring force generated by the at least one pair of spring elements. The spring force can in particular also be referred to herein as the restoring force of the at least one pair of spring elements. In particular, the at least one pair of spring elements is typically designed to effect a restoring force on the second shaft upon an axial movement of the second shaft relative to the first shaft. Typically, the at least one pair of spring elements is designed to effect a restoring force on the second shaft in the direction of the first axial position upon a deflection or movement of the second shaft from the first axial position to the second axial position. When the second shaft is positioned at the second axial position, the deflection of the spring elements can in particular provide freedom from play between the first shaft and the second shaft.In further embodiments, the at least one pair of spring elements can be configured to cause a restoring force on the second shaft in the direction of the second axial position upon deflection or movement of the second shaft in the axial direction from the second axial position towards the first axial position.

[0026] According to typical embodiments, a maximum axial deflection of the second shaft relative to the first shaft is determined or limited by the arrangement and shape of the first spring element and the second spring element, in particular by the axial distance between the first spring element and the second spring element. The maximum axial deflection of the second shaft can, in particular, correspond to the axial distance between the first spring element and the second spring element.

[0027] In some embodiments, the second shaft has a toothing. Typically, the toothing is provided on the side of the second shaft facing away from the first shaft. The toothing can, for example, be a spur toothing or a face toothing, in particular a Hirth toothing.

[0028] According to typical embodiments, a coupling comprises a shaft connection according to one of the embodiments described herein. Typically, the first shaft and the second shaft of the shaft connection are connected to one another by the at least one pair of spring elements of the shaft connection, at least substantially free of play or at least substantially torsionally rigid. Typical couplings can be configured for an actuator in an aircraft, for example, for an actuator of an aircraft control system.

[0029] Typically, the coupling comprises a rotor shaft arranged coaxially with the first shaft and the second shaft. The coupling can comprise a housing which, in particular, at least partially encompasses the rotor shaft. The rotor shaft is typically arranged immovably in the axial direction with respect to the first shaft. The coupling is typically configured to couple the first shaft and the second shaft to the rotor shaft. Typically, the coupling is configured to move the second shaft axially towards the rotor shaft in order to couple the first shaft and the second shaft to the rotor shaft. Typically, the second shaft can be moved away from the rotor shaft in the axial direction to decouple the rotor shaft from the first shaft and the second shaft. The rotor shaft can typically be connected to the shaft of a drive, in particular an electric motor or a hydraulic unit.

[0030] Typically, the second shaft can be arranged at a first axial position in which the rotor shaft is decoupled from the first shaft and the second shaft. Typically, the second shaft can be arranged at a second axial position in which the rotor shaft is coupled to the first shaft and the second shaft. In particular, when the second shaft is arranged at the second axial position, the second shaft and the rotor shaft can be in direct contact and can be connected, for example, in a frictionally engaged or positively engaged manner. In embodiments, the second shaft has a first toothing. The rotor shaft typically has a second toothing configured to engage with the first toothing. The first toothing and the second toothing can each be, for example, a spur toothing or a face toothing, in particular a Hirth toothing.

[0031] In typical embodiments, the coupling comprises a lifting device for moving the second shaft in the axial direction by means of a lifting force generated by the lifting device. According to typical embodiments, the lifting device comprises an electromagnet, in particular one or more magnetic coils. The electromagnet can be arranged in a housing of the coupling. The electromagnet is typically configured to move the second shaft against a restoring force of the at least one pair of spring elements from a first axial position to a second axial position. The first axial position and the second axial position can be provided with respect to the first shaft and the rotor shaft according to embodiments described herein. The movement between the first axial position and the second axial position can also be referred to herein as a "stroke" or as an "axial stroke."Typically, the coupling is designed to perform a defined axial stroke of the second shaft for coupling or decoupling.

[0032] Typically, the restoring force acts in the direction of the first axial position when the second shaft is arranged at the second axial position. Typically, a magnetic force of the electromagnet, which is exerted on a second shaft arranged at the first axial position, acts in the direction of the second axial position. The magnetic force is typically exerted when the electromagnet is energized. The magnetic force can be effected via a magnetic circuit. The magnetic circuit can comprise the electromagnet, the second shaft and, for example, the housing or the rotor shaft. Typically, energizing the electromagnet is suitable for moving the second shaft to the second axial position, in particular for coupling the first shaft and the second shaft to the rotor shaft.The electromagnet is typically configured to exert a magnetic force on the second shaft when the electromagnet is energized, which force is at least equal to the restoring force of the at least one pair of spring elements on the second shaft at the second axial position.

[0033] The at least one pair of spring elements is typically configured to move the second shaft to the first axial position when the electromagnet is de-energized, in order to decouple the rotor shaft from the first shaft and the second shaft. In particular, in embodiments, the at least one pair of spring elements can disengage the second shaft with a first toothing from engagement with a second toothing of the rotor shaft. Typical embodiments can, in particular, be designed as a clutch with a "fail-safe" function, wherein the clutch opens in the event of a failure or de-energization of the electromagnet. Typically, in the absence of magnetic force, the second shaft is pulled by the at least one pair of spring elements toward the first shaft and to the first axial position. In particular, the rotor shaft is decoupled from the first shaft and the second shaft.In embodiments, the first shaft and the second shaft are fixed or braked relative to the housing.

[0034] In further typical embodiments, the electromagnet can be configured to exert a magnetic force on the second shaft in the direction of the first axial position and, in particular, to move it to the first axial position. The at least one pair of spring elements can be configured to exert a spring force on a second shaft arranged at the first axial position in the direction of the second axial position. In particular, the at least one pair of spring elements can be configured to move the second shaft from the first axial position to the second axial position when the electromagnet is de-energized. In particular, the rotor shaft is coupled to the first shaft and the second shaft when the electromagnet is de-energized. The clutch can have a fail-safe function to close the clutch in the event of a failure or disconnection of the electromagnet's power supply.

[0035] In further typical embodiments, the lifting device comprises, alternatively or in addition to the electromagnet, a mechanical lifting device for providing a mechanical lifting force, a hydraulic lifting device for providing a hydraulic lifting force, or a pneumatic lifting device for providing a pneumatic lifting force. Typically, the lifting device provides the lifting force instead of or in addition to the magnetic force of the electromagnet in the axial direction for coupling or uncoupling the clutch. The lifting force typically acts in the axial direction counter to the restoring force of the at least one pair of spring elements. In further typical embodiments, the lifting device comprises an electromagnet and another mechanical, hydraulic, or pneumatic lifting device which provides a lifting force in the same axial direction as the restoring force.The electromagnet can be configured to apply a magnetic force in the axial direction counter to the lifting force and counter to the restoring force, in particular to overcome the lifting force and the restoring force and to move the second shaft axially in the direction of the magnetic force. In typical embodiments, the use of an electromagnet in a lifting device or as a lifting device can have the advantage that an electromagnet can be quickly controlled or can be simple or compact in design. The at least one pair of spring elements can be provided with a low restoring force according to the embodiments described herein, so that the electromagnet can be small and lightweight to apply the necessary magnetic force.

[0036] In typical embodiments, the first shaft or the second shaft can have friction linings, which, when the clutch is disengaged, clamp a friction disc firmly connected to the clutch housing. Typically, both shafts have friction linings on the facing flat surfaces. In particular, a defined friction torque can be provided when the clutch is disengaged.

[0037] According to typical embodiments, a use of a shaft connection or a coupling according to embodiments described herein is specified. The use typically comprises moving the second shaft relative to the first shaft in an axial direction, in particular in a first axial direction from a first axial position to a second axial position.

[0038] Shaft connections according to embodiments described herein typically provide a rigid torque transmission between the first shaft and the second shaft while allowing axial mobility. In embodiments, a shaft connection can be used as a passive coupling element with length compensation, e.g., to compensate for thermal expansion.

[0039] When using a clutch, in particular in a method for actuating a clutch, the use can comprise coupling the first shaft and the second shaft to the rotor shaft. The coupling typically comprises providing a connection between the second shaft and the rotor shaft, in particular a positive or frictional connection. A positive connection can be established in particular by engagement of a first toothing of the second shaft with a second toothing of the rotor shaft. A frictional connection can be established by frictional contact between the rotor shaft and the second shaft. The second shaft is typically moved using a lifting device according to embodiments described herein, in particular by energizing an electromagnet.

[0040] The use of a clutch typically comprises decoupling the first shaft and the second shaft from the rotor shaft. Decoupling typically comprises releasing a connection between the second shaft and the rotor shaft. For example, current supply to the electromagnet can be switched off. The restoring force of the at least one pair of spring elements can release the connection between the second shaft and the rotor shaft. In typical embodiments, the use of a shaft connection or clutch comprises moving the second shaft relative to the first shaft in a second axial direction different from the first axial direction. In particular, the second shaft can be moved from the second axial position to the first axial position, for example by the restoring force of the at least one pair of spring elements.

[0041] In embodiments, the first toothing of the second shaft can engage with the second toothing of the rotor shaft when the at least one pair of spring elements is in a rest position. The electromagnet, in particular, provides a holding force between the rotor shaft and the second shaft. When the current supply to the electromagnet is switched off, the first toothing and the second toothing can slide away from each other above a certain torque. The sliding of the toothing typically leads to a displacement of the second shaft toward the first shaft and to a release of the clutch.

[0042] Typical embodiments can offer the advantage over the prior art that torques can be transmitted between shafts without backlash or with torsion resistance. Typical embodiments can provide a shaft connection that is independent of the direction of rotation. Embodiments can be lightweight. A further advantage can be that only a small lifting force is required to axially move the second shaft relative to the first shaft, counteracting the restoring force of the at least one pair of spring elements. A scattering of restoring forces in series-produced shaft connections can be reliably kept low. Embodiments can provide a relatively large axial stroke with a relatively small diameter of the shaft connection. Typical couplings can be magnetically actuated, in particular, can be switched quickly. Embodiments can be manufactured simply, compactly, or inexpensively.A further advantage may be that embodiments can be equipped with a "fail-safe" function and can be used particularly in safety-critical applications. For example, embodiments can be used in aircraft, for example, in load paths or drive trains of aircraft, particularly in control devices with force feedback. Short description of the drawings

[0043] Further advantages and features of preferred embodiments of the invention are explained below with reference to the accompanying drawings, in which: Fig. 1A shows a schematic view of a typical shaft connection, with the first shaft not shown; Fig. 1B shows a schematic view along the rotation axis of the shaft connection of the Fig. 1A ; Fig. 1C shows a schematic side view of the shaft connection of the Fig. 1A; Fig. 2 shows a schematic view of an arrangement of spring element pairs according to a typical embodiment; Fig. 3 shows a schematic view of another typical shaft connection, the first shaft not being shown; Fig. 4 shows a section of a coupling with a shaft connection according to an embodiment; Fig. 5 shows another section of the coupling of the Fig. 4 with further components of the clutch; and Fig. 6 shows a flowchart of a use of a clutch according to an embodiment. Description of embodiments

[0044] Typical embodiments are described below with reference to the figures, whereby the invention is not limited to the exemplary embodiments, but rather the scope of the invention is determined by the claims. In the description of the figures, the same reference numerals are used for the same or similar parts. In some cases, features that have already been described in connection with other figures are not described again for the sake of clarity. In some cases, features that are shown multiple times in one figure (for example, details of the spring element pairs 9 in Figures 1A to 3 ), marked only once with reference symbols.

[0045] Figures 1A to 1C show schematic views of a shaft connection 1 with a second shaft 7 rotatable about a rotation axis 3 and two pairs of spring elements 9 attached to the second shaft 7. For the sake of clarity, Figures 1A to 1Ca first shaft of the shaft connection 1 is hidden. The second shaft 7 is circular in shape. On the side facing away from the first shaft, the second shaft 7 has a toothing 17. The toothing 17 can, for example, serve to engage with another toothing of a rotor shaft when the shaft connection 1 is used in a coupling.

[0046] On the side of the second shaft 7 facing the first shaft, the two spring element pairs 9 are fastened to the second shaft 7. Each of the spring element pairs 9 comprises a first spring element 11 and a second spring element 13. The first spring element 11 and the second spring element 13 are each fastened to the second shaft 7, in particular via fastening means with a spacer 15. The first spring element 11 and the second spring element 13 are each fastened to the second shaft 7 with a radially inner spring element end, wherein the radially inner spring element end is arranged on a second circle 29 around the axis of rotation 3.

[0047] Furthermore, the first spring element 11 and the second spring element 13 are each configured for attachment to the first shaft. The first spring element 11 and the second spring element 13 are each attached to the first shaft at a radially outer spring element end, which is arranged on a first circle 27 around the rotation axis 3.

[0048] As in Figures 1A and 1C As shown, the first spring element 11 and the second spring element 13 of a spring element pair 9 are arranged axially offset from one another in the direction of the rotation axis 3, in particular axially spaced apart. The first spring element 11 and the second spring element 13 are each designed as elongated leaf springs. The first spring element 11 and the second spring element 13 are each aligned substantially orthogonally to the rotation axis 3, as shown in Fig. 1C shown. In Fig. 1Bthe leaf springs also extend substantially in the circumferential direction around the rotation axis 3, wherein the second spring element 13 crosses the first spring element 11 in the view along the rotation axis 3. The Figures 1A to 1C show a shaft connection with three pairs of spring elements 9, with one pair of spring elements hidden for clarity. In further embodiments, only one pair of spring elements or more than two pairs of spring elements may be provided.

[0049] Fig. 2 shows an arrangement of three pairs of spring elements 9, which are evenly distributed in the circumferential direction around the axis of rotation. In Fig. 2For the sake of clarity, only the spring element pairs 9 and their respective fastening positions are shown. The first spring element 11 of a spring element pair 9 is fastened to the first shaft at a first fastening position 19 and to the second shaft at a second fastening position 21. The second spring element 13 of the spring element pair 9 is fastened to the first shaft at a third fastening position 23 and to the second shaft at a fourth fastening position 25. The first fastening position 19 of the first spring element 11 and the third fastening position 23 of the second spring element 13 lie on a first circle 27 around the axis of rotation for fastening to the first shaft.The second fastening position 21 of the first spring element 11 and the fourth fastening position 25 of the second spring element 13 are located on a second circle 29 for fastening to the second shaft, wherein the second circle 29 has a smaller radius than the first circle 27.

[0050] The first spring element 11 and the second spring element 13 are arranged in a crossed manner, wherein in particular the first fastening position 19 of the first spring element 11 and the fourth fastening position 25 of the second spring element 13 are located at a first angular position 31 with respect to the rotation axis. The second fastening position 21 of the first spring element 11 and the third fastening position 23 of the second spring element 13 are located at a second angular position 33, which is different from the first angular position 31. The first spring element 11 and the second spring element 13 extend over the same angular range. Although the arrangement of the spring elements has only been described for one spring element pair 9, the spring elements of the two further spring element pairs 9 are also Fig. 2 arranged offset in the circumferential direction according to the described arrangement.

[0051] Fig. 3shows schematically a shaft connection 1 with spring element pairs 9, which according to Fig. 2 are fastened to a first shaft (not shown) and to a second shaft 7. The spring elements are connected to the first shaft and the second shaft 7 via fastening means 35. In embodiments, the second shaft 7 has a recess 36 around the respective fastening means 35 at fastening positions provided for fastening spring elements to the first shaft. In particular, the spring elements can be mounted by means of the fastening means 35 through the recesses 36.

[0052] Fig. 4 shows a section of a typical coupling, wherein the section particularly shows a shaft connection 1 for connecting a first shaft 5 and a second shaft 7. The second shaft 7 has a first toothing 45 for coupling with a Fig. 4not shown rotor shaft. Both shafts are ring-shaped and each comprise a radial area in which both shafts extend. The overlapping radial area is shown in the detailed view in Fig. 4 Enlarged view. In the overlapping radial area, the two shafts are arranged one behind the other and connected by pairs of spring elements, which are distributed in the circumferential direction around the rotation axis 3. Each pair of spring elements comprises a first spring element 11 and a second spring element 13, each of which is designed as a leaf spring, for example as in Figures 1 to 3 The leaf springs are each fastened to the first shaft 5 and to the second shaft 7 via fastening means 35. The second shaft 7 is shown in a first axial position in which the spring elements are not deflected and the second shaft 7 is supported by a Fig. 4is decoupled from the rotor shaft (not shown). The second shaft 7 can be moved in the axial direction 37, in particular to a second axial position which is further away from the first shaft 5 than the first axial position.

[0053] Fig. 5 shows another section of the Fig. 4 1 shows a coupling 41 shown with further components of the coupling 41, wherein only one half of the sectional view of the coupling 41 is shown. The coupling 41 comprises a housing 51, a rotor shaft 43, and a shaft connection with pairs of spring elements, a first shaft 5, and a second shaft 7. The housing 51 is secured against rotation. The rotor shaft 43 can be connected, for example, by means of screws 53 to a shaft of an electric motor (not shown). The first shaft 5, the second shaft 7, and the rotor shaft 43 are coaxially rotatable about a rotation axis 3.

[0054] The second shaft 7 has, on the side of the second shaft 7 facing the rotor shaft 43, a first toothing 45 for engagement with a second toothing 47 of the rotor shaft 43. Fig. 5 shows the second shaft 7 in a first axial position in which the spring elements are unloaded. The clutch 41 further comprises an electromagnet 49 with magnetic coils 50. The electromagnet 49 is configured to exert a magnetic force on the second shaft 7 when the magnetic coils 50 are energized, so that the second shaft 7 is pulled against the restoring force of the spring elements in the direction of the rotor shaft 43 into a second axial position in which the first toothing 45 of the second shaft 7 engages the second toothing 47 of the rotor shaft. In particular, when the magnetic coils 50 are energized, the electromagnet closes a magnetic circuit through the housing 51, the rotor shaft 43, and the second shaft 7.

[0055] Fig. 6shows a flow diagram of a use 100 of a clutch 41, such as in Fig. 5 shown. At block 110, the second shaft 7 is moved in a first axial direction to couple the first shaft 5 and the second shaft 7 to the rotor shaft 43. To move the second shaft 7, the electromagnet 49 is energized. The second shaft 7 is pulled by the magnetic force of the electromagnet 49 from a first axial position on the first shaft 5 to a second axial position, wherein the spring element pairs are preloaded without play. At the second axial position, the first toothing 45 of the second shaft 7 engages with the second toothing 47 of the rotor shaft 43. With the engagement of the toothings, the first shaft 5, the second shaft 7 and the rotor shaft 43 are coupled without play and in a torsionally rigid manner in both directions of rotation.

[0056] At block 120, the second shaft 7 is moved in a second axial direction different from the first axial direction to decouple the first shaft 5 and the second shaft 7 from the rotor shaft 43. In particular, the current supply to the electromagnet 49 is switched off. The spring element pairs pull the second shaft back into the first axial position, whereby the first gearing is disengaged from the second gearing 47. In particular, the rotor shaft 43 is decoupled from the first shaft 5 and the second shaft 7. The clutch 41 of the Fig. 5 has a "fail-safe" function, in which, in the event of a failure or shutdown of the electromagnet 49, the rotor shaft 43 is decoupled from the first shaft 5 and the second shaft 7.

Claims

1. Shaft connection (1), comprising - a first shaft (5) rotatable about an axis of rotation (3), - a second shaft (7) arranged coaxially to the first shaft (5) and axially movable relative to the first shaft (5), and - at least one pair of spring elements (9), each having a first spring element (11) and a second spring element (13), wherein the first spring element (11) and the second spring element (13) are each fastened to the first shaft (5) and to the second shaft (7), and wherein the first spring element (11) and the second spring element (13) are arranged axially offset from one another.

2. Shaft connection (1) according to claim 1, wherein the first shaft (5) and the second shaft (7) are arranged one behind the other in an axial direction.

3. Shaft connection (1) according to claim 1 or 2, wherein the first spring element (11) and the second spring element (13) are each designed as a leaf spring.

4. Shaft connection (1) according to claim 3, wherein the leaf spring is aligned at least substantially parallel to a plane orthogonal to the axis of rotation (3).

5. Shaft connection (1) according to claim 3 or 4, wherein the leaf spring is arc-shaped.

6. Shaft connection (1) according to one of claims 3 to 5, wherein the leaf spring extends substantially in the circumferential direction around the axis of rotation (3).

7. Shaft connection (1) according to one of the preceding claims, comprising at least two pairs of spring elements (9), wherein the at least two pairs of spring elements (9) are arranged distributed in the circumferential direction around the axis of rotation (3).

8. Shaft connection (1) according to one of the preceding claims, wherein the first spring element (11) and the second spring element (13) are arranged crossed over.

9. Shaft connection (1) according to one of the preceding claims, wherein the first spring element (11) and the second spring element (13) each extend over the same angular range around the axis of rotation (3).

10. Shaft connection (1) according to one of the preceding claims, wherein the first spring element (11) and the second spring element (13) each have a fastening position on a first circle (27) around the axis of rotation (3) on the first shaft (5), and wherein the first spring element (11) and the second spring element (13) each have a further fastening position on a second circle (29) around the axis of rotation (3) on the second shaft (7).

11. Shaft connection (1) according to one of the preceding claims, wherein the second shaft (7) has a toothing (17).

12. Shaft connection (1) according to one of the preceding claims, wherein the first shaft (5) and / or the second shaft (7) is circular in shape.

13. Coupling (41), comprising - a shaft connection (1) according to one of the preceding claims, and - a rotor shaft (43) arranged coaxially to the first shaft (5) and the second shaft (7), wherein the coupling (41) for coupling the first shaft (5) and the second shaft (7) to the rotor shaft (43) is adapted to move the second shaft (7) axially in the direction of the rotor shaft (43).

14. Coupling (41) according to claim 13, - wherein the second shaft (7) has a first toothing (45), and wherein the rotor shaft (43) has a second toothing (47) configured to engage with the first toothing (45); and / or further comprising an electromagnet (49) configured to move the second shaft (7) against a restoring force of the at least one pair of spring elements (9) from a first axial position to a second axial position.

15. Use of a shaft connection (1) according to one of claims 1 to 12 or a coupling (41) according to one of claims 13 to 14, with movement of the second shaft (7) relative to the first shaft (5) in an axial direction.