Centrifugal pendulum and drive arrangement for a motor vehicle

Description

[0001] The invention relates to a centrifugal pendulum for damping torsional vibrations according to the preamble of claim 1, and to a drive arrangement for a motor vehicle which includes the centrifugal pendulum according to the invention.

[0002] Centrifugal pendulums contain at least one pendulum flange rotatable about an axis of rotation, as well as pendulum masses suspended from it so as to oscillate freely. These pendulum masses oscillate along predetermined paths in the field of centrifugal acceleration. In this way, they can compensate for rotational speed variations, such as those introduced by the torsional vibrations inherent in the operation of internal combustion engines, by being set into oscillation themselves. These oscillations either absorb energy from or add energy to the excitation oscillation, thus damping or reducing the amplitude of the excitation oscillation. Due to the centrifugal force increasing with increasing rotational speed, the centrifugal pendulum acts as a speed-adaptive torsional vibration damper, since both the natural frequency of the centrifugal pendulum oscillation and the excitation frequency are proportional to the rotational speed.

[0003] The coupling device disclosed in DE102006028552 A1, comprising a coupling disc and a coupling hub, is known from the prior art. To optimize the coupling device, particularly with regard to the noise generated during operation when installed, a pendulum mass carrier device of a centrifugal pendulum device, comprising several pendulum masses movably mounted to the pendulum mass carrier device relative to it, is coupled to the coupling disc. The pendulum masses are movably mounted on both sides of a flange element on that element.

[0004] At low engine speeds and the high torque fluctuations that occur in an internal combustion engine, the pendulum masses can strike the boundary of the oscillation chamber. This eliminates the function of a centrifugal pendulum, so vibration isolation is no longer provided.

[0005] German patent DE 102013211391 discloses a speed-adaptive vibration damper and a torsional vibration damper incorporating the vibration damper. The speed-adaptive vibration damper is equipped with a disk section rotating about an axis of rotation and several vibrating damper masses arranged around its circumference along a first oscillation angle forced along an epicycloid first pendulum path and tuned to a predetermined first pendulum order. A center-of-mass path with two pendulum orders is provided, the second pendulum order being smaller than the first. Since the second order no longer corresponds to the motor excitation, the oscillation amplitude of the pendulum masses decreases.

[0006] Another way to reduce the amplitudes of the oscillatory movements of the pendulum masses is to generate friction between the pendulum masses and a support.

[0007] German patent DE 102010049553 A1 discloses that in a centrifugal pendulum device, designed in particular for use in the drive train of a motor vehicle, with several pendulum masses attached to a pendulum support and movable relative to it, the operation of the centrifugal pendulum device is limited to a speed range above a minimum speed. This is achieved by a means that brakes the movement of at least one pendulum mass depending on the speed. The direction of action of this means is radial to the pendulum mass.

[0008] In DE102014211711 A1 and WO2015192846 A1, a centrifugal pendulum is disclosed with a pendulum flange rotatable about an axis of rotation and pendulums distributed around the circumference, suspended in the pendulum flange and suspended in the centrifugal field of the rotating pendulum flange. To prevent the pendulums from impacting the pendulum flange hard, the pendulums are axially pre-tensioned relative to the pendulum flange. This allows the pendulum masses to be held in their radial positions even when the centrifugal force is less than that of gravity.

[0009] DE102015212737 A1 discloses an embodiment of a centrifugal pendulum in which a stop damper is attached to the pendulum mass by means of a retaining element, and which is readable according to the preamble of claim 1.

[0010] Based on this, the present invention aims to provide a centrifugal pendulum that combines reliable damping of excitation vibrations with a cost-effective design and a long service life.

[0011] This problem is solved by the centrifugal pendulum according to claim 1 and by the drive arrangement according to claim 6. Advantageous embodiments of the centrifugal pendulum according to the invention are specified in dependent claims 2 to 5.

[0012] The features of the claims can be combined in any technically meaningful way, taking into account the explanations from the following description as well as features from the figures, which include supplementary embodiments of the invention.

[0013] Within the scope of the present invention, the terms radial, axial and circumferential direction always refer to the axis of rotation of the centrifugal pendulum.

[0014] The invention relates to a centrifugal pendulum for damping torsional vibrations, comprising at least one pendulum flange rotatable about an axis of rotation and several pendulum masses slidably arranged on the pendulum flange for each performing an oscillating motion substantially perpendicular to the axis of rotation. The centrifugal pendulum has a friction sleeve for each pendulum mass, with each friction sleeve being positively and firmly connected to its associated pendulum mass. In this way, frictional forces can be transmitted to the pendulum mass via the friction sleeve simply and reliably. In particular, the pendulum masses can be suspended so as to oscillate freely. The positive connection secures the position of the friction sleeve on the pendulum mass even at elevated temperatures.

[0015] Preferably, each friction sleeve is arranged at least partially on the radial inner side of the pendulum mass. In particular, a portion of the friction sleeve can extend completely along the radial inner side of the pendulum mass and thus be supported in the radial direction against centrifugal forces acting on the pendulum mass.

[0016] Each friction sleeve has at least one axially extending projection that extends into an axially oriented cavity of the pendulum mass. This allows the friction sleeve to grip the pendulum mass radially. Optionally, a radial preload can exist between the axial projection, also known as a snap hook, and the side of the friction sleeve that rests against the pendulum mass. This preload generates radial normal forces that prevent the axially extending projection from unintentionally moving out of the cavity.

[0017] Alternatively or additionally, the friction sleeve can have at least one circumferentially extending projection that extends into a circumferentially extending cavity in the pendulum mass. This means that the friction sleeve can also have a tangentially extending snap hook that can engage in a corresponding cavity in the pendulum mass, either tangentially or circumferentially. Optionally, a radial preload can also exist between the circumferentially extending projection and the side of the friction sleeve that rests against the pendulum mass. This preload allows the resulting radial normal forces to be used to generate frictional forces that prevent the circumferentially extending projection from unintentionally moving out of the cavity.This means that the friction sleeve surrounds the pendulum mass in the circumferential direction on at least one side and preferably on both sides.

[0018] In particular, it can be provided that the material forming the circumferentially extending cavity of the pendulum mass develops a radial recess, and that the circumferentially extending projection of the friction sleeve forms an undercut in the area of ​​the recess. In this way, a positive locking mechanism ensures that the circumferentially extending projection is fixed in or on the pendulum mass, thus increasing the safety against unintentional detachment of the friction sleeve from the pendulum mass.

[0019] In a simple and cost-effective embodiment, the friction sleeve is formed by a plastic casing that partially encloses the respective pendulum mass. This means, for example, that a metal core of the pendulum mass is partially encased in plastic on its outer surface. This casing can have different wall thicknesses on opposite sides of the pendulum mass.

[0020] The centrifugal pendulum has at least one friction device with which a normal force acting essentially parallel to the axis of rotation is realized on a respective friction sleeve, so that when the pendulum mass moves due to the load with the first normal force, a frictional force opposing the movement is generated on the friction sleeve of the respective pendulum mass.

[0021] Preferably, the friction device is an annular leaf spring with which the normal force is exerted on a respective friction sleeve.

[0022] The ring-shaped friction device thus allows a force to be applied, essentially parallel to the axis of rotation, to each of the arranged pendulum masses or to the friction sleeves assigned to the pendulum masses, so that when a pendulum mass moves, a frictional force acts on the pendulum mass or on the friction sleeve assigned to it, opposing the movement of the pendulum mass. The friction device may, in detail, exhibit deviations from a perfectly circular ring shape.

[0023] The friction device is an annular leaf spring that exerts the normal force on a respective friction sleeve. Such an annular bending spring or leaf spring is preferably made of spring steel.

[0024] The bending spring can be supported on the pendulum flange and has several axially extending convex regions, with at least one convex region bearing against and pressing against the friction sleeve of a respective pendulum mass. In this way, the axially parallel normal forces are applied to the pendulum masses via the convex regions, resulting in the vibration-damping frictional forces. Sections of the bending spring located between the convex regions are axially supported on the pendulum flange. This means that the friction device acts on the friction sleeve of a respective pendulum mass on the one hand and is supported on a pendulum flange on the other. The pendulum flange thus provides the corresponding counterforce to the normal force.

[0025] For example, the bending spring can have three evenly distributed, axially protruding corrugations on its circumference as convex areas, which press on correspondingly positioned pendulum masses or friction sleeves.

[0026] A given convex area or corrugation can be located at a greater distance from the plane of arrangement of the annular bending spring on the radial outer side of the ring shape than on the radial inner side. The plane of arrangement is the plane essentially perpendicular to the axis of rotation, which corresponds to the plane of arrangement of the annular bending spring, independent of the convex areas.

[0027] In a further embodiment of the annular bending spring, it is provided that it has axially projecting elements which are suspended in the pendulum flange on which the bending spring is axially supported. These projecting elements ensure a specific angular position of the annular bending spring relative to the pendulum flange, even when the opposing force of the frictional force applied by the bending spring acts on the bending spring tangentially to the rotational movement of the pendulum flanges.

[0028] The normal force applied by the friction device acts essentially parallel to the axis of rotation and thus perpendicular to the direction of movement of the pendulum mass or perpendicular to a tangent of a rotational movement of the pendulum mass.

[0029] The frictional force slows down the movement of the friction sleeve and, due to the mechanical connection of the friction sleeve with the pendulum mass, also the oscillation of the pendulum mass itself, thus damping the oscillation amplitude of the pendulum mass.

[0030] A translational relative motion thus takes place between the moving friction sleeve or the associated pendulum mass on the one hand and a rotationally stationary element on the other, such as the friction device itself or the pendulum flange.

[0031] Because the distance between the pendulum mass and the friction device does not change during its movement, the pendulum mass or the friction sleeve is subjected to an essentially constant normal force, resulting in an essentially constant frictional force.

[0032] The centrifugal pendulum according to the invention can have two pendulum flanges, such that, in addition to the first-mentioned pendulum flange, the centrifugal pendulum has a further, second pendulum flange, wherein the two pendulum flanges are arranged opposite each other along the axis of rotation and the pendulum masses are arranged between the pendulum flanges. The two pendulum flanges are configured to rotate together about the axis of rotation and to absorb the induced vibrations and transmit them to the pendulum masses.

[0033] The friction device can have one or two annular bending springs. For example, a centrifugal pendulum can have only one annular bending spring as its friction device, located between the first pendulum flange and the friction sleeves of the pendulum masses. The normal forces generated by this single bending spring cause the pendulum masses to bear against the second pendulum flange.

[0034] In an alternative embodiment, the centrifugal pendulum has two annular bending springs as a friction device, wherein an annular first bending spring is arranged between the first pendulum flange and the friction sleeves of the pendulum masses, and an annular second bending spring is arranged between the further, second pendulum flange and the friction sleeves of the pendulum masses.

[0035] In the first alternative, when the pendulum masses or their friction sleeve move, frictional forces exist between the friction sleeve and the friction device designed as a bending spring on the one hand, and on the other hand between the pendulum mass or its friction sleeve and the second pendulum flange.

[0036] In the second alternative, the centrifugal pendulum features a friction device in the form of an annular bending spring, in particular an annular leaf spring, which applies a force, essentially parallel to the axis of rotation, to the pendulum masses or their associated friction sleeves. Thus, when a pendulum mass moves, a frictional force acts on the pendulum mass or its associated friction sleeve, opposing the motion of the pendulum mass. Consequently, when the pendulum masses or their friction sleeves move, frictional forces exist between the friction sleeve and the first bending spring on the one hand, and between the pendulum masses or their friction sleeve and the second annular bending spring, which is axially supported by the second pendulum flange, on the other.

[0037] In both cases, the equilibrium with the normal forces applied by the friction device or the bending springs is generated by means of one or more pendulum flanges.

[0038] This means that the pendulum masses, which are axially loaded with the forces from the friction device, are on the other hand directly or indirectly supported on the further pendulum flange in order to create a static equilibrium in the axial direction.

[0039] In a further embodiment, the friction device comprises several helical compression springs that are received in openings or recesses in the pendulum masses and that each exert an axial normal force on the friction sleeve associated with the respective pendulum mass, so that the sleeve is pressed axially against at least one pendulum flange. Each helical compression spring is thus positively engaged in the pendulum mass. The helical compression spring presses axially against the friction sleeve of the respective pendulum mass with a normal force, which in turn presses against a pendulum flange. Due to a relative movement between the friction sleeve and the pendulum flange, a frictional force is generated between these components when the pendulum mass moves. This frictional force opposes the movement, thus damping any oscillation of the pendulum mass.

[0040] In the design of the centrifugal pendulum, in which two pendulum flanges are positioned opposite each other, the helical compression springs are supported axially on axially opposite areas of the friction sleeve or on opposite friction sleeves, which in turn are supported axially on the pendulum flanges.

[0041] In addition, a drive arrangement for a motor vehicle is provided, comprising a drive engine, in particular an internal combustion engine, as well as a vehicle transmission and a centrifugal pendulum according to the invention, wherein the centrifugal pendulum mechanically connects the drive engine and the vehicle transmission rotationally.

[0042] The centrifugal pendulum can be mounted, in particular, on the hub or flange of a clutch disc or directly on a transmission input shaft.

[0043] The invention described above is explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way limited by the purely schematic drawings, and it should be noted that the embodiments shown in the drawings are not limited to the dimensions depicted. It is illustrated in Figure 1 : a centrifugal pendulum according to the invention with a clutch disc in top view, Figure 2 : the centrifugal pendulum with clutch disc in side view, Figure 3 : the centrifugal pendulum in exploded view, Figure 4 : the centrifugal pendulum in top view, Figure 5 : the centrifugal pendulum in a partial section AA, Figure 6 : a pendulum mass with friction sleeve in perspective view, Figure 7: a pendulum mass with friction sleeve of a first embodiment in a partially cutaway view, Figure 8 : the pendulum mass with friction sleeve of the first embodiment in partial section BB, Figure 9 : Detail Y from Figure 8 , Figure 10 : Detail Z from Figure 7 , Figure 11 : the in Figure 7 Pendulum mass with friction sleeve shown in side view, Figure 12 : a pendulum mass with friction sleeve of a second embodiment in a partially cutaway view, Figure 13 : the pendulum mass with friction sleeve of the second embodiment in partial section BB, Figure 14 : Detail Z from Figure 12 , Figure 15 : Detail Y from Figure 13 , Figure 16 : the in Figure 12 Pendulum mass with friction sleeve shown in side view, Figure 17 : a pendulum mass with friction sleeve of a third embodiment in a partially cutaway view, Figure 18 : Sectional view along the section path CC, Figure 19: the pendulum mass with friction sleeve of the third embodiment in partial section BB, Figure 20 : Detail X from Figure 17 , Figure 21 : Detail Y from Figure 19 , Figure 22 : Detail Z from Figure 18 , and Figure 23 : the in Figure 17 Pendulum mass with friction sleeve shown in side view.

[0044] In Figure 1 To illustrate the position of the centrifugal pendulum according to the invention, it is shown in a coaxial arrangement behind clutch discs 2.

[0045] Figure 3 Figure 1 shows this module consisting of clutch discs 2 and centrifugal pendulum in a side view, showing that the clutch discs 2 and the centrifugal pendulum 3 are arranged on a common axis of rotation 1. It is also evident that axially adjacent to the arranged pendulum mass 10, a first pendulum flange 20 and a second pendulum flange 21 are present on both sides, from which the pendulum masses 10 are suspended so as to pivot. Figure 3 Figure 1 shows an exploded view of a centrifugal pendulum, with the two pendulum flanges 20 and 21 visible on the outside. On their sides facing the pendulum masses 10 are a first annular bending spring 31 and a second annular bending spring 32. Three pendulum masses 10 are shown in the center, each with a friction sleeve 40 arranged on its radial inner surface 11.

[0046] Figure 4 The figure shows a centrifugal pendulum according to the invention in a top view, showing that the pendulum masses 10 can protrude radially between the pendulum flanges 20, 21.

[0047] Out of Figure 5The structure and function are shown again. It can be seen that the two bending springs 31, 32 are axially supported on the outer sides of the pendulum flanges 20, 21, thereby exerting axial normal forces Fn on the friction sleeve 40. This causes the indicated frictional forces Fr between the bending spring 31, 32 and the friction sleeve 40 to counteract excessive oscillation during relative movement. The two bending springs 31, 32 together form a friction device 30.

[0048] Figure 6Figure 1 shows a pendulum mass 10 with a friction sleeve 40 positively engaged with it. It is evident that the pendulum mass 10 has an axially extending cavity 12 in its central region, which serves to mount a roller for suspending the pendulum mass and into which axially extending projections 41 of the friction sleeve 40 engage on both sides. This alone restricts the translational degree of freedom of the friction sleeve 40 in the radial direction with respect to the pendulum mass 10. Furthermore, it is evident that the pendulum mass 10 has a circumferentially extending cavity 13 at each of its circumferential boundaries, into which circumferentially extending projections 42 of the friction sleeve 40 extend. Consequently, the rotational degree of freedom of the friction sleeve 40 about the axis of rotation with respect to the pendulum mass 10 is also restricted.

[0049] In Figure 7This embodiment is shown again in a partial section. It can be seen that the friction sleeve 40 rests against the radially inner side 11 of the pendulum mass 10. Furthermore, the previously mentioned details are shown. Figure 6 The details described are also in the Figures 7-10 recognizable.

[0050] In detail Z, which is in Figure 10 As shown, it can also be seen that the circumferentially extending projection 42 of the friction sleeve 40 forms an undercut 43 in the area of ​​a recess 14 of the pendulum mass 10 in order to thus ensure positive locking in the circumferential direction.

[0051] The Figures 12-16Figure 1 shows a second embodiment of the pendulum mass 10 with friction sleeve 40, in which, unlike the previously described embodiment, the friction sleeve 40 does not have an axially extending projection 41, but merely rests against the pendulum mass 10 on both sides. This embodiment can be implemented with lower manufacturing and assembly costs.

[0052] The Figures 17 to 23 A third embodiment of the pendulum mass 10 with friction sleeve 40 is removable, which is located in the central area of ​​the Figures 7-11The variant discussed is similar, but differs circumferentially in that the circumferentially extending projection 42 of the friction sleeve 40 not only extends circumferentially, but also includes axially extending projections 41 on both sides of the pendulum mass 10, which engage axially into the circumferentially extending cavity 13 of the pendulum mass 10, which is also formed in the axial direction, as can be seen in particular from Figure 18 as is evident.

[0053] The long-life centrifugal pendulum proposed here according to the invention can efficiently reduce or eliminate torsional vibrations, particularly in internal combustion engine-driven motor vehicle powertrains. Reference symbol list

[0054] 1 Axis of rotation 2 Coupling disc 3 Centrifugal pendulum 10 Pendulum mass 11 Radially inner side 12 Axially extending cavity 13 Circumferentially extending cavity 14 Recess 20 First pendulum flange 21 Second pendulum flange 30 Friction device 31 First bending spring 32 Second bending spring 40 Friction sleeve 41 Axially extending projection 42 Circumferentially extending projection 43 Undercut Fn Normal force Fr Friction force

Claims

1. A centrifugal pendulum for damping torsional oscillations, having at least one pendulum flange (20) that is rotatable about an axis of rotation (1) and multiple pendulum masses (10) that are arranged in a displaceable manner on the pendulum flange (20) for performing, in each case, an oscillatory movement (2) extending substantially perpendicular to the axis of rotation, wherein the centrifugal pendulum has a sleeve for each pendulum mass (10), wherein a respective sleeve is firmly connected in a form-fitting manner to the respective pendulum mass (10) assigned to it, characterized in that the respective sleeve is designed as a friction sleeve (40), and the centrifugal pendulum has at least one friction device (30) designed as an annular leaf spring, with which a normal force (Fn) acting substantially parallel to the axis of rotation is realized on the respective friction sleeve (40) such that during a movement of the pendulum mass (10) due to the application of the normal force (Fn) a frictional force (Fr) acting against the movement is generated on the friction sleeve (40) of the respective pendulum mass (10), wherein the friction sleeve (40) has at least one axially extending projection (41) that extends into an axially extending cavity (12) of the pendulum mass (10).

2. The centrifugal pendulum according to claim 1, characterized in that the friction sleeve is arranged at least in sections on the radially inner side (11) of the pendulum mass (10).

3. The centrifugal pendulum according to any one of the preceding claims, characterized in that the friction sleeve (40) has at least one projection (42) extending in the circumferential direction that extends into a cavity (13) of the pendulum mass (10) extending in the circumferential direction.

4. The centrifugal pendulum according to claim 3, characterized in that the material of the pendulum mass (10) forming the cavity (13) extending in the circumferential direction forms a recess (14) in the radial direction and the projection (42) of the friction sleeve (40) extending in the circumferential direction forms an undercut (43) in the region of the recess (14).

5. The centrifugal pendulum according to any one of the preceding claims, characterized in that the friction sleeve (40) is formed by a plastic sheathing enveloping the respective pendulum mass (10) in regions.

6. A drive arrangement for a motor vehicle, having a drive motor, in particular an internal combustion engine, and having a vehicle transmission and a centrifugal pendulum according to any one of claims 1 to 6, wherein the centrifugal pendulum mechanically connects the drive motor and the vehicle transmission to one another in a rotating manner.