A crankshaft assembly having a centrifugal pendulum attached to the crankshaft

Abstract

The present invention relates to a crankshaft assembly (1) for a motor vehicle powertrain, the crankshaft assembly comprising a crankshaft section (2) and a centrifugal pendulum (3) fixed to the crankshaft section, the centrifugal pendulum having a carrier (4) fixed to the crankshaft section and at least one pendulum mass (5) movable relative to the carrier (4) along a predetermined track, wherein the crankshaft assembly (1) has a friction unit (7) connected to the carrier (4), the friction unit resting on at least one of the pendulum masses (5) such that the friction unit (7) exerts a frictional torque on the pendulum mass (5) with the relative movement of the pendulum mass (5) relative to the carrier (4), thereby hindering the relative movement, wherein the friction unit (7) extends over a peripheral section of less than 360°.

Description

Field of the Invention

[0001] The present invention relates to a crankshaft assembly for a motor vehicle powertrain. The crankshaft assembly has a crankshaft section and a centrifugal pendulum fixed to the crankshaft section. The centrifugal pendulum has a carrier fixed to the crankshaft section and at least one pendulum mass that moves relative to the carrier along a predetermined track. Background Art

[0002] It is known from the prior art to attach a centrifugal pendulum to a crankshaft in order to absorb the natural vibrations of the crankshaft. For example, DE 102016 121 397 A1 and DE 10 2017 120 426 A1 each disclose a pendulum assembly radially attached to the outer peripheral surface of a crankshaft.

[0003] However, a drawback still remaining in the prior art is that providing a centrifugal pendulum requires additional installation space and increases the overall weight of the crankshaft, and additionally, connecting the centrifugal pendulum to the crankshaft weakens the crankshaft. Summary of the Invention

[0004] Accordingly, it is an object of the present invention to avoid or at least mitigate the drawbacks of the prior art. In particular, there is provided a crankshaft assembly in which the centrifugal pendulum can be designed in a space-saving and weight-saving manner, and the centrifugal pendulum can be attached to the crankshaft without negatively affecting function, strength, manufacturability, and / or cost.

[0005] This object is achieved by a crankshaft assembly having the features of claim 1. Advantageous refinements are claimed in the dependent claims.

[0006] Thus, the crankshaft assembly has a crankshaft section, i.e., a particular axial section of the crankshaft, and a centrifugal pendulum particularly directly fixed to the crankshaft section. The centrifugal pendulum serves to absorb the natural vibrations of the crankshaft. Thus, the torsional vibrations / rotation of the crankshaft can be eliminated by the centrifugal pendulum. The centrifugal pendulum is preferably tuned to a higher vibration order; for example, tuned to a vibration order greater than the first order, preferably greater than the second order. For example, the centrifugal pendulum can be tuned to the third order, fourth order, four and a half order, sixth order, etc.

[0007] The centrifugal pendulum has a carrier fixed to the crankshaft section and at least one pendulum mass that moves relative to the carrier along a predetermined track. In order to satisfy the resonance conditions for compensating torsional vibrations, the track preferably has sections in the circumferential direction and in the radial direction.

[0008] In particular, the crankshaft section can have a mass region that is eccentrically arranged (relative to the rotational axis of the crankshaft / crankshaft section), and an imbalance is generated / driven to be imbalanced during the operation / rotation of the crankshaft assembly through this mass region. The mass region is formed, for example, by the connecting rod bearing region of the crankshaft section.

[0009] The crankshaft assembly has a friction device, in particular a friction device that is non-rotatably fixed to the carrier, which abuts against at least one pendulum mass such that when the pendulum mass moves relative to the carrier, the friction device exerts a frictional torque that impedes the relative movement on the pendulum mass. This has the advantage that the additional friction acting on the centrifugal pendulum, in particular the oscillatory movement of the pendulum mass, improves the isolation of the natural vibrations of the crankshaft, and the required vibration angle can be reduced. In this way, functional parameters such as mass, vibration angle, and friction can be provided to the required degree.

[0010] The friction device extends over a peripheral section of less than 360°. This means that the friction device is not designed to be fully circumferentially extended in the circumferential direction. The circumferential direction is defined in particular with respect to the rotational axis of the crankshaft section. This has the advantage that the friction device can be formed only in the regions where the friction device is required. In addition, the non-circular friction device has an advantageous effect on compensating for the imbalance caused by the crankshaft section. The peripheral section can preferably be between 90° and 270°, in particular between 180° and 270°.

[0011] According to a preferred embodiment, at least one pendulum mass extends over a predetermined peripheral section. The peripheral section over which the friction device extends can particularly correspond to the predetermined peripheral section. Thus, the normal force / axial force and the friction element contact are provided by the friction device only in the region of one or more pendulum masses. Additionally, this has the advantage that the friction device does not need additional contact surfaces in the regions where one or more pendulum masses are not formed.

[0012] According to an advantageous refinement, the friction device can be segmented, in particular in the form of substantially annular (circular) sectors. This shape has proven to be particularly advantageous for use in the crankshaft section.

[0013] According to a preferred embodiment, the friction device can have a friction element that abuts against the pendulum mass, a receiving disk that is non-rotatably connected to the carrier, and a spring element that is axially supported / tensioned between the friction element and the receiving disk. The normal force / axial force is exerted on the friction element by the spring element, and the normal force / axial force axially presses the friction element against the pendulum mass.

[0014] The receiving disk can preferably be formed over a peripheral section of less than 360°, for example between 90° and 270°, in particular between 180° and 270°. Alternatively or additionally, the friction element can preferably be formed over a peripheral section of less than 360°, for example between 90° and 270°, in particular between 180° and 270°. Alternatively or additionally, the spring element can preferably be formed over a peripheral section of less than 360°, for example between 90° and 270°, in particular between 180° and 270°.

[0015] According to a preferred embodiment, the friction device may additionally have a cover disk axially arranged between the spring element and the friction element. When providing the cover disk, the contact surface between the spring element and the friction element, i.e., relative to the friction element, can be enlarged so that the allowable surface pressure of the friction element is not exceeded.

[0016] The cover disk may preferably be formed on a peripheral section of less than 360°, for example, between 90° and 270°, particularly between 180° and 270°.

[0017] According to a preferred embodiment, the friction device may be arranged circumferentially substantially opposite to a mass region of the crankshaft section that generates imbalance and is particularly eccentrically arranged relative to the axis of rotation. This has the advantage that the mass of the friction device in the mass region can contribute to compensating for the imbalance.

[0018] According to a preferred embodiment, the friction device may have an axisymmetric design. In particular, the axis of symmetry of the friction device may correspond to the axis of symmetry of the mass region that orthogonally intersects the axis of rotation, for example. This configuration has a particularly advantageous effect on the concentricity / imbalance compensation of the crankshaft section.

[0019] According to a particularly preferred embodiment, the mass of the centrifugal pendulum can be dimensioned and its position on the crankshaft section can be selected such that the centrifugal pendulum has an imbalance compensation effect on the crankshaft section during operation, i.e., during the rotation of the crankshaft section. The friction device can be regarded as part of the centrifugal pendulum. This means that the centrifugal pendulum and / or the friction device thus form an imbalance compensation mass for the crankshaft / crankshaft section. Therefore, the centrifugal pendulum replaces the imbalance mass (otherwise, the imbalance mass should be provided, i.e., if there is no centrifugal pendulum). Thus, it can be said that the imbalance occurring during the rotation of the crankshaft section is mainly or completely compensated by the mass of the centrifugal pendulum and the selection of the fixed position of the centrifugal pendulum on the crankshaft section.

[0020] This has the advantage that the centrifugal pendulum not only realizes the actual absorption function but also plays a role in imbalance compensation. Due to this dual function of the centrifugal pendulum, the total mass / total weight of the crankshaft assembly (or the crankshaft) does not increase due to the provision of the centrifugal pendulum. Since the centrifugal pendulum replaces the imbalance mass, the individual mass / weight of the crankshaft section is reduced due to the imbalance mass replaced / eliminated by material removal, which in turn corresponds to the individual mass / weight of the added centrifugal pendulum. In short, the weight of the crankshaft remains the same with and without the centrifugal pendulum. In other words, the imbalance mass of the crankshaft has an additional centrifugal pendulum function.

[0021] According to a preferred embodiment, the crankshaft section can have a front recess for enclosing at least a part of the centrifugal pendulum. The recess can in particular be dimensioned such that it has an imbalance compensation effect when the crankshaft section rotates. This means that in particular so much material / mass is removed from the recess that the recess is compensated again by the provision of an additional component, namely the centrifugal pendulum. The recess can subsequently be provided by machining or can already be provided in the blank of the crankshaft section. Thus, manufacturing costs can be saved.

[0022] According to a preferred embodiment, the volume of the recess can be at least partially compensated by the volume of the centrifugal pendulum (and / or friction device). In other words, the recess is arranged such that the volume can be used for arranging components such as the centrifugal pendulum.

[0023] In particular, the recess can be arranged substantially at the same height as the mass region of the crankshaft section in the axial direction. The recess can also be arranged substantially opposite the mass region in the circumferential direction. Furthermore, it can be advantageous to arrange the recess radially at substantially the same distance from the rotational axis as the mass region when the mass region, for example the center of gravity of the mass region (in another direction) is remote from the rotational axis.

[0024] According to an advantageous embodiment, the centrifugal pendulum can have a number of pendulum masses. In particular, according to an advantageous embodiment, the pendulum masses can be arranged asymmetrically in the circumferential direction. The imbalance characteristics of the crankshaft assembly are favorably affected by the non-uniform distribution in the circumferential direction.

[0025] Alternatively or additionally, according to a preferred embodiment, the center of gravity generated by the pendulum mass, in particular one or more pendulum masses, can be arranged substantially opposite the mass region of the crankshaft section in the circumferential direction.

[0026] According to a preferred embodiment, a centering region for centering the accommodation of the centrifugal pendulum can be formed on the outer peripheral part in the radial direction of the crankshaft section. The centering region can subsequently be provided by machining or can already be provided in the blank of the crankshaft section. Thus, manufacturing costs can be saved.

[0027] According to a preferred embodiment, a screwed-on surface to which the centrifugal pendulum is fixed can be formed on the axial end face of the crankshaft section. Due to the axial attachment, the required vibration angle of the centrifugal pendulum can be particularly easily achieved. The screwed-on surface can be machined later or can already be provided in the blank of the crankshaft section. Thus, manufacturing costs can be saved. Preferably, threaded holes can be provided in the crankshaft section in the region of the screwed-on surface such that the centrifugal pendulum (carrier) can be easily screwed in.

[0028] Particularly preferably, the screwed-on surface is arranged radially outside the connecting region of the crankshaft section, where the connecting region is designed to connect a second adjacent crankshaft section to the crankshaft section. This ensures that the crankshaft section is not impermissibly weakened in its stress-critical region due to the fixing of the centrifugal pendulum. For example, the screwed-on surface can be arranged circumferentially essentially opposite the mass region of the crankshaft section.

[0029] Further preferably, the friction device and the centrifugal pendulum are attached to the crankshaft section, for example to the screwed-on surface, via a common fixing device. This has the advantage that, for example, the number of threaded holes can be reduced, so that the crankshaft section is weakened as little as possible.

[0030] In one embodiment, the friction device can be designed to surround and extend in the circumferential direction. For example, the friction element can have a cross-section in the shape of a ring, i.e., the friction element can be designed as a friction ring. The rotationally symmetric design of the friction element means that the friction element can be manufactured particularly inexpensively and assembled easily.

[0031] For example, the receiving disk can be designed as a bevelled sheet metal part. For example, the receiving disk is manufactured without using a cutting method, for example as a formed part, in particular a deep-drawn part. The receiving disk can preferably have two radial sections, which are connected to each other via an axial section, resulting in a longitudinal section with a substantially S-shaped shape. The first (inner) radial section can be used as a fixing section for attachment to the crankshaft section. The second (outer) radial section can be used as a supporting section for axially supporting the spring element and / or the friction element. The receiving disk can be folded over at its radially outer end, i.e., the receiving disk can have an axially protruding part against which the friction element rests in the circumferential direction.

[0032] The spring element can be designed as a disc spring or a corrugated spring. In particular, the spring element can be attached to the receiving disk in a rotationally fixed manner. For example, the spring element can be attached to the receiving disk in a non-rotatable manner by a riveted connection.

[0033] According to a preferred embodiment, the crankshaft assembly can have a rupture protection part (catcher), which is particularly fixed to the crankshaft section and radially surrounds the centrifugal pendulum on the outside, so that the parts of the centrifugal pendulum that become loose during the rotation of the centrifugal pendulum are caught and / or braked by the rupture protection part. In other words, the centrifugal pendulum is enclosed by the rupture protection part, so that the centrifugal pendulum is radially surrounded / enclosed on the outside. This has the advantage that parts that become loose due to rotation are not thrown outwards in an uncontrolled manner. Therefore, the rupture protection part forms a barrier for the parts that fly outwards due to centrifugal force, and as a result, damage to other parts of the motor vehicle powertrain can be prevented.

[0034] According to a preferred embodiment, the rupture protection member may have: a radial section that extends radially outward on a first axial side (opposite to the crankshaft section) of the centrifugal pendulum; and an outer axial section that extends axially from the radial section, particularly from the radially outer end of the radial section, to a second (crankshaft-section-facing) axial side of the centrifugal pendulum on the radially outer side of the centrifugal pendulum. In other words, the rupture protection member extends in the direction of the crankshaft section on the radially outer side of the centrifugal pendulum. In particular, the outer axial section extends at least far enough so that one or more pendulum masses are completely covered in the axial direction. In particular, the radial section extends radially outward so far that the radial section extends radially outward beyond the centrifugal pendulum (pendulum mass). The outer axial section and the radial section are connected, for example, via an offset section / bending section.

[0035] According to a preferred embodiment, the outer axial section may extend on a peripheral section of less than 360°, preferably between 90° and 270°. In other words, the outer axial section has a cross-section in the shape of an arc. In particular, the outer axial section only extends on the peripheral section where one or more pendulum masses are arranged. This has the advantage that the rupture protection member is only formed where it has to fulfill its function, so that material and thus weight can be saved. In particular, the space required for the crankshaft section is not restricted by the rupture protection member.

[0036] According to a preferred embodiment, the friction device, particularly the receiving disk, may form the rupture protection member. This means that the component, particularly the receiving disk, extends such that the receiving disk radially surrounds the centrifugal pendulum on the outside and can be used as a rupture protection member. This has the advantage that no additional components need to be provided to form the rupture protection member. The receiving disk can be lengthened in a particularly suitable manner due to its structure without affecting other functions of the receiving disk or the centrifugal pendulum.

[0037] The receiving disk may preferably be designed as a bevelled sheet metal part. The sheet metal part can be made into the desired bevelled shape in a particularly simple manner. Bevelling is particularly understood here to mean that the receiving disk has a radial section, an outer axial section, and an inner axial section that extends axially from the radially inner end of the radial section, particularly in the direction of the second axial side of the centrifugal pendulum. Thus, the radial section and the two axial sections form a longitudinal section in a U-shape, and one or more pendulum masses of the centrifugal pendulum are arranged within this U-shaped longitudinal section (such that one or more pendulum masses are surrounded). The bevelled offset of the receiving disk improves the stability of the component.

[0038] [[ID=,12]]In particular, the receiving disk can be formed without using a cutting method, for example, formed as a formed part, preferably formed as a deep-drawn part. Thus, geometries, particularly U-shaped and / or S-shaped geometries, can be easily produced.

[0039] According to a preferred embodiment, the friction element can be received in a rotationally fixed manner on its radially outer side in a receiving disk, in particular in an axial section of a rupture protection member / receiving disk. Thus, the friction element can be arranged more radially outwards such that the friction surface is advantageously enlarged.

[0040] According to a preferred embodiment, the friction element can have protrusions protruding radially outwards, which engage in corresponding recesses in the receiving disk to prevent rotation. In other words, the anti-rotation device is achieved by the recesses in the receiving disk and the through-parts in the friction element. In this way, the friction element can be attached to the receiving disk in a form-fitting and non-rotatable manner that is easy to manufacture.

[0041] According to a preferred embodiment, the receiving disk can alternatively (or additionally) have radially inwards protruding deformation regions, for example in the form of arc-shaped spring stops in a dual-mass flywheel, which engage in corresponding cavities in the friction element to prevent rotation. In this way, the friction element can be attached to the receiving disk in a form-fitting and non-rotatable manner that is easy to manufacture.

[0042] According to a preferred embodiment, the friction element can rest axially against a radial section of the receiving disk. The fact that the friction element is supported on a larger area on both sides advantageously prevents the friction element from tilting.

[0043] According to a preferred embodiment, the carrier of the centrifugal pendulum can extend in the circumferential direction on the side opposite the pendulum mass such that the friction device rests against the carrier. This means that the carrier forms a contact portion for the friction device in the circumferential direction on the side opposite the pendulum mass. This has the advantage that even if one or more pendulum masses are arranged asymmetrically in the circumferential direction within an angular range where the friction device does not abut against one or more pendulum masses, one-sided loading and misalignment of the friction device can be avoided or compensated for. In other words, the missing contact portion is compensated for by the special geometry of the carrier of the centrifugal pendulum. Thus, a part of the carrier is provided for receiving one or more pendulum masses, and the remaining part is designed such that it provides a contact surface for the friction device.

[0044] In particular, the friction element of the friction device can rest against (or be supported on) the carrier. This means that the friction element rests against one or more pendulum masses in a first peripheral region and against the carrier in another, particularly substantially opposite, second peripheral region. Thus, one-sided loading on the friction element is avoided.

[0045] The friction device can preferably rest on at least one pendulum mass and on the carrier on the same axial side. This has the advantage that the normal force exerted by the spring element can be uniformly supported and / or supported over a (larger) area.

[0046] According to an advantageous refinement, the carrier can have a support section extending in the radial direction for receiving at least one pendulum mass and a contact section extending in the radial direction for supporting a friction device. The support section and the contact section are preferably arranged spaced apart parallel to one another in the axial direction. In this way, a flat contact surface for the friction device can be provided in an advantageous manner, and at the same time the support of the pendulum mass on the carrier can be ensured.

[0047] According to an advantageous refinement, the axial distance between the support section and the contact section can essentially correspond to the thickness of at least one pendulum mass. This has the advantage that a flat friction element can rest flush axially against the pendulum mass and the contact section, or can be supported on the pendulum mass and the contact section.

[0048] According to an embodiment, the support section and the contact section can be connected by a connecting section of the bracket such that the bracket has a longitudinal section with a substantially S-shaped shape. This ensures sufficient stiffness and strength of the carrier.

[0049] Furthermore, it has proven advantageous to form the contact section by displacing the carrier in the direction of the friction device. In this way, a carrier of the desired shape can be produced without effort.

[0050] In addition, it is advantageous for the carrier to be designed as a sheet metal part. For example, the carrier can be manufactured without using cutting methods. In particular, the carrier can be produced by stamping and forming, for example by deep drawing. Thus, the carrier can be produced inexpensively and in large quantities.

[0051] The cross-section of the contact section can preferably have the shape of a circular arc. This has the advantage that the contact section provides a suitable contact surface for a simple design of the friction element.

[0052] In other words, the present invention relates to a crankshaft assembly in which a centrifugal pendulum assembly is arranged on an imbalance compensation flange of a crankshaft section. A recess for the centrifugal pendulum assembly is provided on the crankshaft section, which is machined or already formed on a blank, such that a centering seat, a screwed-in surface, and a region in which one or more pendulum masses can move are provided. A centrifugal pendulum carrier (flange) is arranged on the screwed-in surface, which is screwed into a threaded hole of the crankshaft section in a non-stress-critical region. Additional friction acting on the centrifugal pendulum movement is provided by a friction device, which improves the isolation of the natural vibrations of the crankshaft and reduces the required vibration angle. The friction device has a chamfered receiving disk. On the one hand, a disk spring is supported on the receiving disk, and on the other hand, a normal force acts on a friction element, which in turn rests on the pendulum mass. If required, a cover disk can also be provided between the disk spring and the friction element, such that the allowable surface pressure of the friction element is not exceeded. The friction element is designed such that it cannot rotate together with the receiving disk, such that the friction point is fixed between the friction element and the pendulum mass. The pendulum masses are arranged circumferentially asymmetrically, such that the pendulum masses are used to compensate for the imbalance in the crankshaft. In particular, the friction device can be non-circumferential, but only designed as a ring section, thereby providing a normal force and a friction ring contact in the required region of the pendulum mass, and there is no exposed region where the friction device needs to be supported. In this way, the mass of the friction device in the unwanted region can also compensate for the imbalance caused by the mass already removed from the crankshaft section for the centrifugal pendulum. The receiving disk, the spring element, the friction element, and the cover disk can be segmented / non-circumferential and only present in the region of the pendulum mass. Alternatively or additionally, a rupture protection element can preferably be incorporated into the receiving disk (support disk / receiving plate), for which purpose the receiving plate extends radially outwards to enclose the centrifugal pendulum. The anti-rotation device between the receiving plate and the friction element (friction ring) can be achieved by means of a recess in the receiving plate and a penetration in the friction element, or alternatively by means of a formed region in the receiving plate, which engages in a corresponding recess in the friction element. Furthermore, in particular, in the case where the pendulum masses are arranged non-symmetrically in the circumferential direction, the carrier of the centrifugal pendulum can be designed such that the carrier forms an abutment for the friction device. Thus, only a part of the carrier is provided for receiving the pendulum mass, and the remaining region is designed such that a contact surface is provided for the friction device. More preferably, the contact surface can be formed by an annular region enclosed in the direction of the friction device. Description of the Drawings

[0053] The present invention will be described below with reference to the drawings. In the drawings:

[0054] Figure 1 and Figure 2 shows a longitudinal sectional view and a plan view of a crankshaft assembly in a first embodiment,

[0055] Figure 3 and Figure 4 show a longitudinal sectional view and a plan view of a crankshaft assembly in a second embodiment,

[0056] Figure 5 and Figure 6 show a longitudinal sectional view and a plan view of a crankshaft assembly in a third embodiment, and

[0057] Figures 7 to 9 show a longitudinal sectional view and a perspective view of a crankshaft assembly in a fourth embodiment.

[0058] The drawings are essentially schematic only and are provided solely for understanding the present invention. Identical elements are provided with the same reference numerals. The features of the respective embodiments may be interchanged. Detailed Embodiment

[0059] Figures 1 to 9 show different embodiments of a crankshaft assembly 1 for a motor vehicle powertrain. The crankshaft assembly 1 has a crankshaft section 2. The crankshaft section 2 is in particular an axial section of the crankshaft. The crankshaft assembly 1 has a centrifugal pendulum 3 attached to the crankshaft section. The centrifugal pendulum 3 is used to absorb the natural vibrations of the crankshaft or the main excitation orders of the motor vehicle powertrain.

[0060] The centrifugal pendulum 3 has a carrier 4 fixed to the crankshaft section. Thus, the carrier 4 is attached to the crankshaft section 2 in a rotationally fixed manner. The centrifugal pendulum 3 also has a pendulum mass 5. The pendulum mass 5 is attached to the carrier 4 such that the pendulum mass can move relative to the carrier 4 along a predetermined path. The absorption effect of the centrifugal pendulum 3 is achieved by the relative movement between the pendulum mass 5 and the carrier 4. In the illustrated embodiment, the centrifugal pendulum 3 has a plurality of pendulum masses 5 arranged asymmetrically in the circumferential direction / circumferentially. The circumferential direction is defined relative to the rotational axis of the crankshaft section 2.

[0061] The mass of the centrifugal pendulum 3 is dimensioned and its position on the crankshaft section 2 is arranged such that the centrifugal pendulum 3 acts on the crankshaft section 2 to compensate for the imbalance during operation, i.e., when the crankshaft section 2 rotates. The crankshaft section 2 has a mass region 6 that generates an imbalance during operation. The mass region 6 is arranged eccentrically with respect to the axis of rotation. Therefore, the mass and position of the centrifugal pendulum 3 match the mass and position of the mass region 6. The centrifugal pendulum 3 (in particular its pendulum mass 5) is arranged opposite the mass region 6 in the circumferential direction. The centrifugal pendulum 3 is arranged in the axial direction (relative to the axis of rotation) at the same height as the mass region 6. The distance by which the pendulum mass 5 is radially spaced from the axis of rotation is the same as the distance by which the mass region 6 is radially spaced from the axis of rotation. In other words, the centrifugal pendulum 3 serves as an imbalance compensation element for the mass region 6. This means that the centrifugal pendulum 3 (partially or fully) replaces the imbalance mass for the crankshaft section 2.

[0062] The crankshaft assembly 1 has a friction device 7 connected to the carrier 4. The friction device 7 is attached to the carrier 4 and / or the crankshaft section 2 in an anti-torque manner. The friction device 7 rests against at least one pendulum mass 5 such that the friction device 7 exerts a frictional torque that impedes relative movement on the pendulum mass 5 when the pendulum mass 5 moves relative to the carrier 4. The friction device 7 has a friction element 8 that contacts the pendulum mass 5. The friction device 7 has a receiving disk 9 that is non-rotatably connected to the carrier 4. The friction element 8 is non-rotatably connected to the receiving disk 9. The friction device 7 has a spring element 10 that is axially supported, in particular axially braced, between the friction element 8 and the receiving disk 9. The spring element 10 is designed as, for example, a disk spring or a corrugated spring. The spring element 10 exerts a normal force / axial force on the friction element 8 that axially presses the friction element 8 against the pendulum mass 5 such that a frictional torque that impedes relative movement is generated when there is relative movement between the friction element 8 fixed to the carrier and at least one pendulum mass 5.

[0063] The crankshaft section 2 has an imbalance compensation flange 11. The imbalance compensation flange 11 is positioned opposite the mass region 6 in the circumferential direction. The crankshaft section 2 has a front-side recess 12 (in the imbalance compensation flange 11) for receiving at least a part of the centrifugal pendulum 3, in particular the pendulum mass 5. The recess 12 is dimensioned such that the recess has an imbalance compensation effect when the crankshaft section 2 rotates. In particular, the mass removed for the recess 12 corresponds to the mass added by the centrifugal pendulum 3.

[0064] The crankshaft section 2 has a connection region 13 which is designed to attach the (axially adjacent) second crankshaft section to the connection region. The connection region 13 is arranged centrally on the crankshaft section 2. A recess 12 is arranged radially outside the connection region 13. The crankshaft section 13 has a centering region 14 on its radial outer periphery for receiving the centrifugal pendulum 3 of the centrifugal pendulum in a centered manner. The crankshaft section 13 has a screwed-in region / screwed-in surface 15 on its axial end face to which the centrifugal pendulum 3 / carrier 4 is fixed. The screwed-in surface 15 is arranged radially outside the connection region 13. The centrifugal pendulum 3 is axially attached to the screwed-in surface 15 via a fixing device 16 which is in particular in the form of a plurality of screws. For this purpose, threaded holes are provided in the screwed-in surface 15 into which the fixing device 16 is screwed.

[0065] The receiving disk 9 of the friction device 7 is designed as an obliquely cut metal plate part. The receiving disk 9 has a (inner) first radial section 17 which serves as a fixing section. The radial section 17 is firmly attached to the carrier 4 and the crankshaft section 2 via a fixing device. An axial section 18 extends axially away from the crankshaft section 2 / screwed-in surface 15 from the radially outer end of the first radial section 17. The axial section 18 extends radially within the pendulum mass 5. An (outer) second radial section 19 extends radially outwards from the axially distal end of the axial section 18. Thus, the receiving disk 9 at least partially has an S-shaped form. The spring element 10 and / or the friction element 8 are axially supported on the receiving disk 9 in the region of the second radial section 19. An axial projection 20 extends axially towards the pendulum mass 5 from the radially outer end of the second radial section 19. The spring element 10 and / or the friction element 8 are circumferentially supported on the axial projection 20.

[0066] In the illustrated embodiment, the centrifugal pendulum 3 has a plurality of pendulum mass packages. Each pendulum mass package has two pendulum masses 5 which are held axially parallel and spaced apart by one or more spacer elements 21. For example, the two pendulum masses 5 are connected to each other by rivets 22.

[0067] Figure 1 and Figure 2 A first embodiment of the crankshaft assembly 1 is shown. Figure 1A plan view without the friction device 7 is shown. The carrier 4 has a central through-hole 23 through which the carrier 4 is centered on the centering region 14. In the first embodiment, the friction element 8 is designed as a friction ring extending in the circumferential direction. The friction element 8 has a form-fitting element 24 on its radially inner side, which engages with a corresponding recess 25 in the receiving disk 9 for form-fitting anti-rotation protection. The friction element 8 is thus radially fastened on the inside. The receiving disk 9 is designed to surround and extend in the circumferential direction. The second radial section 19 and / or the axial projection 20 are designed to be rotationally symmetric.

[0068] Figure 3 and Figure 4 A second embodiment of the crankshaft assembly 1 is shown. Only the differences from the first embodiment will be explained below. The friction device 7 has an additional cover disk 26 which is arranged axially between the spring element 10 and the friction element 8. The crankshaft assembly 1 has a rupture protection member 27. The rupture protection member 27 radially surrounds the centrifugal pendulum 3 on the outside. Thus, when the centrifugal pendulum 3 rotates, loose parts are captured by the rupture protection member 27. The rupture protection member 27 is formed by the receiving disk 9. The second radial section 19 extends radially outwards such that the second radial section projects radially outwards beyond the pendulum mass 5. An outer axial section 28 extends axially from the radially outer end of the second radial section 19 towards the crankshaft section 2. The outer axial section 28 extends axially beyond the pendulum mass 5. This means that the axial projection 20 is lengthened axially at least in the peripheral region of the pendulum mass 5 in order to form the outer axial section 28. The pendulum mass 5 is accordingly enclosed by the receiving disk 9. In order to form the rupture protection member 27, the receiving disk 9 has an obliquely cut U-shaped shape which axially surrounds the pendulum mass 5. The friction element 8 is radially fastened on the outside of the receiving disk 9 to prevent rotation. For example, the friction element 8 and the receiving disk 9 engage with each other. The friction element 8 is supported on the cover disk 26 in the radially inner region and on the receiving disk 9 in the radially outer region. The carrier 4 extends approximately in a crescent shape in the region of the pendulum mass 5.

[0069] Figure 5 and Figure 6Shows a third embodiment of the crankshaft assembly 1. Only the differences from the first embodiment or the second embodiment will be explained below. In the third embodiment, the friction device 7, in particular the receiving disk 9, the friction element 8, the spring element 10 and / or the covering disk 26 extend over a peripheral section of less than 360°. This means that the friction device 7 is not designed to be fully circumferential in the circumferential direction. The peripheral section is between 90° and 270°, in particular between 180° and 270°. The peripheral section substantially corresponds to the predetermined peripheral section over which the pendulum mass 5 extends. The friction device 7 is segmented and is shown in the form of a circular (ring-shaped) sector in this embodiment. The friction device 7 can be regarded as part of the centrifugal pendulum 3, so that the configuration, dimensions and positioning of the friction device 7 also have an imbalance compensation effect on the crankshaft section 2 during operation.

[0070] Figures 7 to 9 Shows a fourth embodiment of the crankshaft assembly 1. Only the differences from the first embodiment, the second embodiment or the third embodiment will be explained below. In the fourth embodiment, the carrier 4 of the centrifugal pendulum 3 extends in the circumferential direction on the side opposite to the pendulum mass 5, so that the friction device 7 rests against the carrier 4. The carrier 4 thus extends in the radial and circumferential directions up to the mass region 6. The carrier 4 has a connecting section in the form of an axially beveled section 29, which connects a first radial section 30 adjacent to the pendulum mass 5 in the circumferential direction to a second radial section 31 adjacent to the mass region 6 in the circumferential direction. The second radial section 31 is enclosed in the direction of the friction device 7. The first radial section 30 is arranged axially spaced apart from and parallel to the second radial section 31. The first radial section 30 serves as a support section for receiving the pendulum mass 5. The second radial section 31 serves as a contact section against which the friction device 7 rests. In particular, the friction element 8 rests against the second radial section 31 in one peripheral section and against the pendulum mass 5 in another peripheral section on the same axial side. The carrier 4 has a through-hole 32. The through-hole 32 is formed eccentrically. In the region adjacent to the pendulum mass 5 in the circumferential direction, the radially inner part / inner surface of the carrier 4 rests against the centering region 14. The through-hole 32 extends further radially outwards in the region adjacent to the mass region 6 in the circumferential direction, so that the carrier 4 rests against the crankshaft section 2 only over a peripheral section of less than 360°.

[0071] List of reference numerals

[0072] 1 Crankshaft assembly

[0073] 2 Crankshaft section

[0074] 3 Centrifugal pendulum

[0075] 4 Carrier

[0076] 5 pendulum mass

[0077] 6 mass area

[0078] 7 friction device

[0079] 8 friction element

[0080] 9 receiving tray

[0081] 10 spring element

[0082] 11 imbalance compensation flange

[0083] 12 recess

[0084] 13 connection area

[0085] 14 centering area

[0086] 15 screwed-in surface

[0087] 16 fixing device

[0088] 17 first radial section

[0089] 18 axial section

[0090] 19 second radial section

[0091] 20 axial projection

[0092] 21 spacer element

[0093] 22 rivet

[0094] 23 through hole

[0095] 24 form-fitting element

[0096] 25 recess

[0097] 26 cover plate

[0098] 27 break protection

[0099] 28 axial section

[0100] 29 chamfered section

[0101] 30 first radial section

[0102] 31 second radial section

[0103] 32 through hole.

Claims

1. A crankshaft assembly (1) for a motor vehicle powertrain, the crankshaft assembly comprising a crankshaft section (2) and a centrifugal pendulum (3) fixed to the crankshaft section, the centrifugal pendulum having a carrier (4) fixed to the crankshaft section and at least one pendulum mass (5) movable relative to the carrier (4) along a predetermined path, characterized in that, The crankshaft assembly (1) has a friction device (7) connected to the carrier (4), the friction device resting on at least one of the pendulum masses (5) such that the friction device (7) exerts a frictional torque on the pendulum mass (5) with the relative movement of the pendulum mass (5) relative to the carrier (4), thereby impeding the relative movement, wherein the friction device (7) extends over a peripheral segment of less than 360°, the friction device (7) having a friction element (8) resting on the pendulum mass (5), a receiving disk (9) fixed to the carrier (4), and a spring element (10) axially supported between the friction element (8) and the receiving disk (9), wherein the receiving disk (9), the friction element (8) and / or the spring element (10) are formed over a peripheral segment of less than 360°.

2. The crankshaft assembly (1) according to claim 1, characterized in that, The peripheral segment is between 90° and 270°.

3. The crankshaft assembly (1) according to claim 1 or 2, characterized in that, At least one of the pendulum masses (5) extends over a predetermined peripheral segment, wherein the peripheral segment over which the friction device (7) extends corresponds to the predetermined peripheral segment.

4. The crankshaft assembly (1) according to claim 1 or 2, characterized in that, The friction device (7) is designed to be segmented.

5. The crankshaft assembly (1) according to claim 1 or 2, characterized in that, The friction device (7) is arranged circumferentially substantially opposite the imbalance-generating mass region (6) of the crankshaft section (2).

6. The crankshaft assembly (1) according to claim 5, characterized in that, The friction device (7) is designed to be axially symmetric, wherein the axis of symmetry of the friction device (7) corresponds to the axis of symmetry of the mass region (6).

7. The crankshaft assembly (1) according to claim 1, characterized in that, The centrifugal pendulum (3) and / or the friction device (7) are dimensioned relative to one or more masses and selected in their position on the crankshaft section (2) such that the centrifugal pendulum (3) and / or the friction device (7) act on the crankshaft section (2) to compensate for any imbalance when the crankshaft section (2) rotates.

8. The crankshaft assembly (1) according to claim 7, characterized in that, The crankshaft section (2) has a front-side recess (12) for receiving at least a part of the centrifugal pendulum (3) and / or the friction device (7), wherein the recess (12) is dimensioned to compensate for any imbalance when the crankshaft section (2) rotates.

9. The crankshaft assembly (1) according to claim 7 or 8, characterized in that, A screwed-in surface (15) is formed on the axial end face of the crankshaft section (2), and the friction device (7) and the centrifugal pendulum (3) are attached to the screwed-in surface via a common fixing device (16).

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