centrifugal pendulum

Abstract

Centrifugal pendulum for damping rotational irregularities introduced via a drive shaft of a motor vehicle engine, comprising a first support flange (16) having a first pendulum track (20) for indirect or direct connection to the drive shaft, a second support flange (18) having a second pendulum track (22) for indirect or direct connection to the drive shaft, and at least one pendulum mass (12) guided in the first pendulum track (20) and in the second pendulum track (22) relative to the first support flange (16) and the second support flange (18) to generate a restoring torque opposing the rotational irregularity, wherein the first support flange (16) has at least one radially inwardly projecting first mounting projection (26) and the second support flange (18) has at least one radially inwardly projecting second mounting projection (28).wherein the first fastening element (26) and the second fastening element (28) are arranged one behind the other in the circumferential direction, characterized in that the first fastening element (26) has a first primary contact surface pointing in a motor-side first axial direction and the second fastening element (28) has a second primary contact surface pointing in the first axial direction, wherein the first primary contact surface and the second primary contact surface are arranged in a common radial plane.

Description

The invention relates to a centrifugal pendulum with the aid of which pendulum masses can be displaced to a different radius under the influence of centrifugal force during rotational speed fluctuations in order to generate a restoring torque directed opposite to the rotational speed fluctuation, whereby the extent of the rotational speed fluctuation can be damped. In this case, a centrifugal pendulum is provided for damping rotational irregularities introduced via a drive shaft of a motor vehicle engine, having a first carrier flange having a first pendulum path for indirect or direct connection to the drive shaft, a second carrier flange having a second pendulum path for indirect or direct connection to the drive shaft, and at least one pendulum mass which is guided in the first pendulum path and in the second pendulum path relative to the first carrier flange and the second carrier flange for generating a restoring torque which is directed counter to the rotational irregularity, wherein the first carrier flange has at least one first fastening shoulder projecting radially inward and the second carrier flange has at least one second fastening shoulder projecting radially inward, wherein the first fastening shoulder and the second fastening shoulder are arranged one behind the other in the circumferential direction.A centrifugal pendulum has a pendulum mass which can be displaced relative to a carrier flange via rollers guided in corresponding tracks and which can generate an oppositely directed restoring torque in the event of a speed fluctuation. The centrifugal pendulum can have two carrier flanges, each of which has a pendulum track in which the pendulum mass can be guided via rollers. The carrier flanges can each have fastening shoulders which project radially inward and by means of which the carrier flanges are riveted to one another.U.S. Pat. No. 2,096,999 A discloses an elastic coupling device which is arranged between a crankshaft of an aircraft engine and a propeller shaft, with vibrating bodies for damping. The vibrating bodies are pinions. A plurality of the pinions are arranged distributed around the periphery around a gearwheel which is formed rigidly with the crankshaft. A ring gear is connected to the propeller shaft. The respective pinion is operatively connected to a pendulum mass via two levers. Two levers are situated axially opposite one another and pass through the ring gear radially. At the end, the opposing levers are provided with pendulum tracks. In the pendulum paths of the levers, bolts are guided on the left and right sides, on which the pendulum masses are suspended.There is a constant need to reduce the installation space requirement of drive trains damped by torsional oscillations.The object of the invention is to show measures which make possible a torsional vibration-damped drive train with a low installation space requirement.The object is achieved according to the invention by a centrifugal pendulum having the features of claim 1. preferred embodiments of the invention are specified in the dependent claims, which can each represent an aspect of the invention individually or in combination.According to the invention, the first fastening attachment has a first primary contact surface pointing in a first axial direction, in particular on the engine side, and the second fastening attachment has a second primary contact surface pointing in the first axial direction, wherein the first primary contact surface and the second primary contact surface are arranged in a common radial plane. The first carrier flange and the second carrier flange can thereby be placed on a substantially planar fastening surface of a carrier part, in particular a part on the motor side, and fastened to the carrier part. For this purpose, the carrier part does not require any shaped depressions or elevations in order to contact both the first fastening attachment and the second fastening attachment, so that the carrier part can be shaped in a correspondingly simple and cost-effective manner. The carrier part can be, for example, a flywheel connected to the drive shaft in a rotationally fixed manner or a primary mass or secondary mass of a dual-mass flywheel.The first fastening attachment and the second fastening attachment are not arranged one behind the other in the axial direction. Instead, the fastening attachments are arranged offset from one another in the circumferential direction. As a result, the axial extent of the centrifugal pendulum in the region of the fastening attachments can be reduced. In this case, use is made of the finding that the fastening attachments do not extend over the entire circumference and otherwise unused installation space is available for the respective other fastening attachment in the circumferential direction between the fastening attachments. Furthermore, the realization is exploited that the centrifugal pendulum is in any case also connected via the fastening projections to a carrier part, for example a flywheel connected to the drive shaft, so that it is not necessarily necessary to provide the centrifugal pendulum as a pre-assembled structural unit and instead the first carrier flange and the second carrier flange can each be connected separately to the carrier part. In particular, if a stop and / or a spacer bolt limiting the oscillation angle is provided in a radius at the height of the pendulum mass, the first carrier flange can be connected to the second carrier flange via the stop, the spacer bolt and / or a comparable component and thus already form a pre-assembled structural unit, so that it is not necessary to additionally connect the first carrier flange to the second carrier flange via the fastening attachments. Due to the offset arrangement of the fastening attachments in the circumferential direction, an arrangement of the fastening attachments in the axial direction one behind the other is avoided, so that axial installation space is saved in the region of the fastening attachments, whereby a torsional vibration-damped drive train with a small installation space requirement is made possible.The at least one pendulum mass of the centrifugal pendulum has the tendency under the influence of centrifugal force to assume a position as far away as possible from the center of rotation. The "zero position" is thus the position radially furthest away from the center of rotation, which the pendulum mass can assume in the radially outer position. At a constant drive speed and constant drive torque, the pendulum mass will assume this radially outer position. In the case of speed fluctuations, the pendulum mass deflects along its pendulum path on account of its mass inertia. The pendulum mass can thereby be displaced in the direction of the center of rotation. The centrifugal force on the pendulum mass is thereby divided into one component tangentially and another component normal to the pendulum path. The tangential force component provides the restoring force which the pendulum mass wishes to return to its "zero position", while the normal force component acts on a force introduction element which initiates the rotational speed fluctuations, in particular the drive shaft of the motor vehicle engine, and generates there a counter-torque which counteracts the rotational speed fluctuation and dampens the initiated rotational speed fluctuations. In the case of particularly severe speed fluctuations, the pendulum mass can therefore have a maximum swing out and assume the position lying radially furthest inwards. The tracks provided in the carrier flange and / or in the pendulum mass have curvatures suitable for this purpose. In particular, more than one pendulum mass is provided. The inertial mass of the pendulum mass and / or the relative movement of the pendulum mass to the carrier flange is designed in particular for damping a specific frequency range of rotational irregularities, in particular an engine order of the motor vehicle engine.Particularly preferably, the first fastening attachment has a first secondary contact surface pointing in a second axial direction, in particular on the transmission side, and the second fastening attachment has a second secondary contact surface pointing in the second axial direction, wherein the first secondary contact surface and the second secondary contact surface are arranged in a common radial plane. The first carrier flange and the second carrier flange can thereby be placed on a substantially planar fastening surface of a carrier part, in particular a carrier part on the transmission side, and fastened to the carrier part. For this purpose, the carrier part does not require any shaped depressions or elevations in order to contact both the first fastening attachment and the second fastening attachment, so that the carrier part can be shaped in a correspondingly simple and cost-effective manner. The carrier part can be, for example, a counter plate of a friction clutch for coupling the drive shaft to at least one transmission input shaft, wherein a clutch plate that can be connected to the transmission input shaft in a rotationally fixed manner can be frictionally pressed between the counter plate and the pressure plate by a pressure plate that can be axially displaced relative to the counter plate.In particular, the first fastening attachment has a first fastening opening and / or the second fastening attachment has a second fastening opening, wherein the first fastening attachment is connected to the second fastening attachment by positive engagement via the first fastening opening and / or the second fastening opening, wherein in particular in the first fastening opening and in the second fastening opening a fastening means, in particular a rivet, is inserted in each case for fastening the first carrier flange and / or the second carrier flange to a motor-side carrier part and / or to a transmission-side carrier part. The fastening openings make it possible to fasten the centrifugal force pendulum easily, in particular rivet it, to the carrier part via the fastening shoulders. Due to the additional free installation space created in the region of the fastening shoulders, for example, a correspondingly more stable rivet connection with a larger diameter of the rivet shank and / or with a closing head and / or setting head that is larger in the axial direction can be used. The number of rivet connections can thereby be reduced, whereby the assembly effort is reduced, and / or the maximum torque that can be transmitted via the fastening attachments can be increased essentially in a neutral manner with respect to installation space. Furthermore, the clamping length of the rivet connection can be reduced, in particular substantially by 1 / 3, compared to a rivet connection simultaneously riveting the carrier part, the first carrier flange and the second carrier flange.Particularly preferably, the motor-side support part is plastically deformed into the first fastening opening and / or into the second fastening opening. The carrier part can thereby be riveted to the corresponding carrier flange via a stud riveting into the respective fastening opening. The number of components can thereby be kept small, as a result of which the assembly of the centrifugal pendulum can be simplified.In particular, the transmission-side carrier part forms a friction surface for a friction clutch for coupling the drive shaft to at least one transmission input shaft. The carrier part can be, for example, a counter plate of a friction clutch for coupling the drive shaft to at least one transmission input shaft, wherein a clutch plate that can be connected to the transmission input shaft in a rotationally fixed manner can be frictionally pressed between the counter plate and the pressure plate by a pressure plate that can be axially displaced relative to the counter plate. The support part can be embodied comparatively thick in the axial direction in order to be able to remove frictional heat introduced via the friction surface. Due to the greater material thickness of the carrier part, a durable and stable stud riveting can be formed particularly easily.Preferably, the first carrier flange and the second carrier flange are identically shaped. The first carrier flange and the second carrier flange can be formed as identical parts, whereby the production costs can be reduced by mass production. During assembly, the identically shaped carrier flanges can be positioned mirror-symmetrically to one another and rotated relative to one another in the circumferential direction until the pendulum tracks of the first carrier flange and the pendulum tracks of the second carrier flange are arranged one behind the other in overlapping fashion, as viewed in the axial direction.Particularly preferably, N pendulum tracks are provided in the first carrier flange and in the second carrier flange, wherein the first fastening attachment is arranged offset from the second fastening attachment substantially by n·3 360° / N in the circumferential direction, wherein n and N are natural integer positive numbers. The number of first fastening lugs and the number of second fastening lugs is in particular less than the number of pendulum tracks and preferably less than the number of pendulum masses. As a result, a free space for a second fastening attachment remains in the circumferential direction between the first fastening attachments and a free space for a first fastening attachment remains between the second fastening attachments if the carrier flanges configured as identical parts are rotated with respect to one another in the circumferential direction to such an extent that the respective pendulum tracks are arranged one behind the other in the axial direction. Depending on the number of pendulum tracks and the arrangement of the fastening lugs, a relative rotation of the first carrier flange to the second carrier flange can be suitable in comparison with a mirror-image arrangement until the next overlapping of the pendulum tracks of the carrier flanges or a later overlapping of the pendulum tracks. Preferably, the pendulum masses and the pendulum paths guiding the respective pendulum mass are uniformly distributed in the circumferential direction. For example, i=3, i=4, i=5 or i=6 pendulum masses with preferably N=2·i pendulum paths per carrier flange can be provided.In particular, the first carrier flange and the second carrier flange are connected to one another on a radius at the height of the pendulum mass, wherein in particular the first carrier flange is connected to the second carrier flange via a stop arranged on the radius at the height of the pendulum mass limiting the oscillation angle of the pendulum mass and / or a spacer bolt arranged at the height of the pendulum mass. As a result, the first carrier flange and the second carrier flange can already form a pre-assembled structural unit, in particular together with the pendulum mass, so that it is not necessary to connect the first carrier flange to the second carrier flange additionally to one another via the fastening shoulders and to align them with one another during the assembly of the centrifugal pendulum in a drive train of a motor vehicle.The invention further relates to a drive train for driving a motor vehicle, having a drive shaft of a motor vehicle engine and a centrifugal pendulum coupled to the drive shaft, which can be designed and further developed as described above, for damping rotational irregularities introduced via the drive shaft. Due to the offset arrangement of the fastening shoulders of the centrifugal pendulum in the circumferential direction, an arrangement of the fastening shoulders one behind the other in the axial direction is avoided, so that axial installation space is saved in the region of the fastening shoulders, whereby a torsional vibration-damped drive train with a small installation space requirement is made possible.The invention is explained below by way of example with reference to the attached drawings on the basis of preferred exemplary embodiments, wherein the features illustrated below can represent an aspect of the invention both individually and in combination. The following are shown: FIG. 1 : shows a schematic sectional view of a first embodiment of a centrifugal pendulum, FIG. 2 : shows a schematic plan view of the centrifugal pendulum from FIG. 1, FIG. 3 : shows a schematic sectional view of a second embodiment of a centrifugal pendulum, and FIG. 4 : shows a schematic sectional view of a third embodiment of a centrifugal pendulum.The centrifugal pendulum 10 shown in FIG. 1 has a multi-part pendulum mass 12 which is guided via rollers 14 on a first carrier flange 16 on the motor side and a second carrier flange 18 on the transmission side. For this purpose, the respective roller 14 is guided in a first pendulum track 20 of the first carrier flange 16 and in a second pendulum track 22 of the second carrier flange 18 as well as in a track 24 formed in the pendulum mass 12. The first carrier flange 16 has a plurality of first fastening attachments 26 cranked on the transmission side and protruding radially inward, while the second carrier flange 18 has a plurality of second fastening attachments 28 cranked on the motor side and protruding radially inward.A motor-side carrier part 34 designed as a flywheel with a starter ring 32 and a transmission-side carrier part 40 designed as a counter plate of a friction clutch can be connected in a rotationally fixed manner to a drive shaft of a motor vehicle engine via a connecting means 30 designed as a screw to a friction surface 36 for a clutch disk 38 of the friction clutch. In the exemplary embodiment shown, the first carrier flange 16 and the second carrier flange 18 are fastened to the motor-side carrier part 34 via fastening means 42 designed as rivets, wherein alternatively the first carrier flange 16 and / or the second carrier flange 18 can be fastened, for example riveted, to the transmission-side carrier part. To receive the respective fastening means 42, the first fastening attachment 26 has a first fastening opening 44 and the second fastening attachment 28 has a second fastening opening 46.As shown in FIG. 2, the first fastening attachments 26 are arranged offset in the circumferential direction with respect to the second fastening attachments 28, so that the fastening attachments 26, 28 are arranged not one behind the other in the axial direction but one behind the other in the circumferential direction, whereby axial installation space can be saved. The first carrier flange 16 and the second carrier flange 18 can be designed as identical parts, wherein in the arrangement of the first carrier flange 16 offset in the circumferential direction relative to the second carrier flange 18, the first pendulum track 20 and the second pendulum track 22 are each arranged in an exactly overlapping manner in the axial direction, so that the guidance of the pendulum mass 12 is not impaired. In the exemplary embodiment shown, the first carrier flange 16 is offset relative to the second carrier flange 18 by a comparatively small angle in the circumferential direction, so that the first fastening extension 26 is arranged adjacent to the second fastening extension 28 and a free space 48 is formed in the circumferential direction between the first fastening extensions 26 and second fastening extensions 28, which are arranged essentially in pairs in each case, and the volume of which can be used as installation space for a further component.In the embodiment of the centrifugal pendulum 10 shown in FIG. 3, in comparison with the embodiment of the centrifugal pendulum 10 shown in FIG. 1, the fastening means 42 configured as a rivet connection is replaced by a stud rivet 50. Here, material of the motor-side carrier part 34 can be plastically deformed into the first fastening opening 44 of the first fastening attachment 26 and into the second fastening opening 46 of the second fastening attachment 28, or vice versa.In the embodiment of the centrifugal pendulum 10 shown in FIG. 4, the wart riveting 50 to the transmission-side carrier part 40 is implemented in comparison to the embodiment of the centrifugal pendulum 10 shown in FIG. 3. Alternatively, the stud rivet 50 may be replaced by the rivet shown in FIG. 1 using the fastener 42 or another joining technique.List of reference characters10 Centrifugal pendulum 12 Pendulum mass 14 Caster wheel 16 First carrier flange 18 Second carrier flange 20 First pendulum track 22 Second pendulum track 24 Raceway 26 First fastening attachment 28 Second fastening attachment 30 Connecting means 32 Starter ring 34 Motor-side carrier part 36 Friction surface 38 Clutch disk 40 Transmission-side carrier part 42 Fastening means 44 First fastening opening 46 Second fastening opening 48 Free space 50 Wart riveting

Claims

Centrifugal pendulum for damping rotational irregularities introduced via a drive shaft of a motor vehicle engine, having a first carrier flange (16), which has a first pendulum track (20), for indirect or direct connection to the drive shaft, a second carrier flange (18), which has a second pendulum track (22), for indirect or direct connection to the drive shaft, and at least one pendulum mass (12), which is guided in the first pendulum track (20) and in the second pendulum track (22) relative to the first carrier flange (16) and the second carrier flange (18), for generating a restoring torque directed counter to the rotational irregularity, wherein the first carrier flange (16) has at least one first fastening shoulder (26) projecting radially inwards and the second carrier flange (18) has at least one second fastening shoulder (28) projecting radially inwards, wherein the first fastening attachment (26) and the second fastening attachment (28) are arranged one behind the other in the circumferential direction, characterized in that the first fastening attachment (26) has a first primary contact surface pointing in a first axial direction on the engine side and the second fastening attachment (28) has a second primary contact surface pointing in the first axial direction, wherein the first primary contact surface and the second primary contact surface are arranged in a common radial plane.Centrifugal pendulum according to Claim 1, characterized in that the first fastening attachment (26) has a first secondary bearing surface pointing in a transmission-side, second axial direction, and the second fastening attachment (28) has a second secondary bearing surface pointing in the second axial direction, wherein the first secondary bearing surface and the second secondary bearing surface are arranged in a common radial plane.Centrifugal pendulum according to either of Claims 1 and 2, characterized in that the first fastening attachment piece (26) has a first fastening opening (44) and the second fastening attachment piece (28) has a second fastening opening (46), the first fastening attachment piece (26) being connected to the second fastening attachment piece (28) in a positively locking manner via the first fastening opening (44) and the second fastening opening (46), a fastening means (42), in the form of a rivet, being inserted in the first fastening opening (44) and in the second fastening opening (46) for fastening the first carrier flange (16) to a motor-side carrier part (34) and the second carrier flange (18) to the motor-side carrier part (34).Centrifugal pendulum according to claim 3 characterised in that the motor-side support part (34) is plastically deformed into the first fastening opening (44).Centrifugal pendulum according to Claim 4da characterized in that the transmission-side carrier part (40) forms a friction surface (36) for a friction clutch for coupling the drive shaft to at least one transmission input shaft.Centrifugal pendulum according to one of Claims 1 to 5da, characterized in that the first carrier flange (16) and the second carrier flange (18) are of identical shape.Centrifugal pendulum according to one of Claims 1 to 6da characterized in that N pendulum tracks (20, 22) are provided in the first carrier flange (16) and in the second carrier flange (18), wherein the first fastening attachment (26) is arranged offset with respect to the second fastening attachment (28) substantially by n · 360° / N in the circumferential direction, wherein n and N are natural integer positive numbers.Centrifugal pendulum according to one of Claims 1 to 7, characterized in that the first carrier flange (16) and the second carrier flange (18) are connected to one another on a radius at the level of the pendulum mass (12), wherein the first carrier flange (16) is connected to the second carrier flange (18) via a stop which limits the oscillation angle of the pendulum mass (12) and / or a spacer bolt which is arranged at the level of the pendulum mass (12).

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