DE102021102856A1 - Torsional vibration damper with arc springs and lever springs arranged in series - Google Patents

Abstract

The application relates to a torsional vibration damper (1), which is constructed as a dual-mass flywheel and is used in a drive train of a motor vehicle, comprising a primary mass (2) and a secondary mass (3) which can be rotated together and rotated to a limited extent relative to one another, with a damper stage between them (6) whose arc springs (5) are supported on the primary mass (2) and a support flange (9) of the secondary mass (3) and elastic deformation occurs according to a spring characteristic of the arc springs (5) and enclosing a lever spring (11). further damper stage (10) is connected in series to the first damper stage (6), the lever springs (11) being inserted between the carrier flange (9) and an output hub (13) of the secondary mass (3), whose elastic deformation corresponds to a spring characteristic of the Lever springs (11) takes place.

Description

The application relates to a torsional vibration damper constructed as a dual-mass flywheel, also known as a torsional vibration damper, which can be used in a drive train of a motor vehicle, comprising a primary mass and a secondary mass which can be rotated together and rotated relative to one another to a limited extent, according to the features of the preamble of claim 1.

In motor vehicles that are driven by internal combustion engines, a non-continuous torque in the form of torsional vibrations is transmitted to the drive train by the operation of the internal combustion engine from its crankshaft. Torsional vibration dampers constructed as dual-mass flywheels are known from the prior art for damping the torsional vibrations.

the DE 10 2012 202 255 A1 shows a torsional vibration damper that can be used to absorb or dampen torsional vibrations and is constructed as a two-mass flywheel, which is arranged in a drive train between the crankshaft of the internal combustion engine and, for example, a shift clutch upstream of the manual transmission. In order to achieve a relatively limited torsion between the primary mass and the secondary mass of the torsional vibration damper, a damper stage including arc springs is provided between the primary mass and the secondary mass, the elastic deformation of which occurs according to a spring characteristic, also known as a torsional characteristic.

From the FR 30 69 603 A1 is a torsional vibration damper constructed as a dual-mass flywheel and intended for a drive train of a motor vehicle, in which elastic lever springs are arranged as damping elements between the primary and secondary masses. With the lever springs, on the one hand, a torque is transmitted and, on the other hand, the torque is damped at the same time. The lever springs, which are fastened in a rotationally and positionally fixed manner to a mass, are each operatively connected to a supporting roller which is assigned to the further mass.

The application is based on the object of providing a functionally improved torsional vibration damper with an extended spring characteristic, with this measure being simple in terms of production engineering and being able to be implemented cost-effectively for a series construction.

The aforementioned task is solved by a torsional vibration damper including the features of claim 1 . Preferred configurations are specified in the subclaims and the following description.

The solution consists in a torsional vibration damper including two damper stages, with a first damper stage including arc springs being followed in series by a second damper stage equipped with lever springs. The lever springs of the second damper stage are arranged between the carrier flange and an output hub of the secondary mass, and their elastic deformation occurs when the primary mass and the secondary mass rotate relative to each other according to the spring characteristic of the lever springs.

The present concept combines a first damper stage including arc springs with a second damper stage comprising lever springs, the second damper stage being connected in series with the first damper stage and being assigned to the secondary mass. In the operating state of the torsional vibration damper, elastic deformation of the arc springs combined with bending of the lever springs due to the extended spring characteristic enables optimized damping or reduction of disadvantageous oscillations, vibrations and rotational irregularities between the primary mass and the secondary mass.

Due to the damper stages arranged in a series connection, their elastic spring elements, the arc springs and lever springs, are combined as energy stores. This advantageously results in a clearly lengthened spring characteristic, the overall length of which results from adding the individual characteristic curves of the spring elements. Consequently, due to the structure of the torsional vibration damper, which comprises two damper stages, a damping characteristic appropriate to the task can be realized, which is advantageously characterized by a long spring characteristic. Associated with this, there is a reduction in rotational irregularities in the drive train, which decisively improves the driving comfort of the motor vehicle.

The structural design of the torsional vibration damper, which includes two damper stages and is designed as a series damper, provides that the first damper stage, including arc springs, is connected to the second damper stage, including lever springs, via an intermediate component, a section of the carrier flange. The extended spring characteristic achieved by the two damper stages improves damping on the one hand and also protects the torsional vibration damper against disadvantageously high torque peaks, so-called impacts, on the other.

The two-stage torsional vibration damper is particularly suitable for installation in a hybrid drive train, in particular for a DHT hybrid application (dedictated hybrid transmission). In a hybrid application, the axle drive of the motor vehicle can be purely electric via an internal combustion engine or by means of a combined drive, with the axle drive including a switch disconnect clutch. Alternatively, the torsional vibration damper can also be integrated into other drive trains of motor vehicles. Advantageously, the torsional vibration damper, which has an extended spring characteristic, can be produced by means of simple, cost-effective measures in terms of manufacturing technology, which further simplify the assembly or assembly and enable a cost-optimized series construction.

According to a preferred embodiment, it is provided that a spring characteristic of ≧110° can be realized through the combination of the arc springs and the lever springs of both damping stages. With a corresponding design of the arc springs and the lever springs, a spring characteristic of ≥ 120°, also known as the torsion characteristic, can be achieved.

An advantageous structural design of the torsional vibration damper includes a multi-part secondary mass. Two offset torsionally fixed lever springs on an output hub of the secondary mass are each guided displaceably via a free end on a support roller or bearing roller, which is rotatably arranged in a stationary manner on the carrier flange. In the operating state, with a relative rotation between the primary mass and the secondary mass, an elastic deformation of the lever springs occurs, in that the free ends of both lever springs each roll off an associated support roller.

The two lever springs of the second damper stage, also referred to as elastic vanes or rails, are preferably positioned on the output hub offset by, for example, 180° from one another. Via the free end, the lever springs are directly non-positively in an operative connection with a supporting roller assigned to the carrier flange. As an alternative to a support roller or bearing roller, a roller bearing can also be provided, for example, on whose rotatable roller bearing ring the lever springs are supported and guided.

According to a further advantageous design, it is provided that the extended spring characteristic curve generated by the two damper stages used in combination is realized through the use of arc springs and lever springs designed to match. The arc springs and lever springs installed in pairs each have the same spring stiffness or spring characteristics. In order to specifically influence the course of the curve of the extended spring characteristic, for example to present a stepped characteristic course, it is advisable to use arc springs and lever springs with spring stiffnesses that differ from one another.

As a measure to ensure functional reliability, a stop is advantageously assigned to each lever spring in order to limit the angular deflections between the primary mass and the secondary mass. For this purpose, the stops are positioned in such a way that when a relative rotation is achieved, a cohesive rotation between the components connecting the lever springs, the output hub and the carrier flange always occurs.

Furthermore, in order to achieve an optimal interaction of both centrifugal masses, it is advantageously provided that the secondary mass is supported radially on the inside via the carrier flange via a bearing point indirectly on the primary mass. The bearing point preferably forms a holding element which is fixed to the primary mass and is designed as a folded sheet metal disc, which engages in a central opening of the carrier flange. To reduce wear and/or to optimize friction, it is advisable to arrange a support bearing designed as a slide bearing or roller bearing on the holding element, via which the carrier flange is supported. The holding element is preferably fastened by means of screws with which the primary mass and consequently the torsional vibration damper is fastened to the crankshaft of the internal combustion engine. In addition, a friction element can be arranged in an annular gap in the area of the bearing point between the holding element and the primary mass in order to avoid direct axial contact.

According to a further embodiment, the torsional vibration damper including two damper stages can also be combined with a centrifugal pendulum of a known type. For this purpose, the centrifugal pendulum is preferably fastened to the output hub outside of the torque flow of the torsional vibration damper and is positioned on the output side at an axial distance in front of the damper stage including lever springs. In addition, the torsional vibration damper described enables the installation of a torque limiter of a known type if required.

For effective protection of the interior of the torsional vibration damper and to achieve a basic friction or basic hysteresis when rotating between the primary mass and the secondary mass of the torsional vibration damper is preferably a disk between the output hub and a cover element of the primary mass membrane used. Advantageously, the disk spring membrane fastened to the output hub together with the lever springs via rivet connections is supported radially on the outside on an inner side of the cover element via a friction and/or sealing disk. As a measure for producing a cost-effective, weight-optimized torsional vibration damper, it is advisable to design essential components such as the primary mass, the carrier flange, the output hub and the plate spring membrane as sheet metal parts that can be easily produced without cutting.

• 1 eine erste Ausführungsform eines Drehschwingungsdämpfers mit zwei Dämpferstufen im Halbschnitt;
• 2 eine schematische Prinzipskizze des Drehschwingungsdämpfers gemäß 1;
• 3 eine zweite Ausführungsform eines Drehschwingungsdämpfers mit zwei Dämpferstufen im Halbschnitt;
• 4 eine schematische Prinzipskizze des Drehschwingungsdämpfers gemäß 3;
• 5 einen vergrößerten Ausschnitt des Drehschwingungsdämpfers gemäß 3;
• 6 den Verlauf unterschiedlicher Federkennlinien.

The subject of the application is explained below on the basis of two embodiments with reference to the attached figures. However, the application is not limited to the embodiments shown. It shows:

• 1 a first embodiment of a torsional vibration damper with two damper stages in half section;
• 2 according to a schematic outline sketch of the torsional vibration damper 1 ;
• 3 a second embodiment of a torsional vibration damper with two damper stages in half section;
• 4 according to a schematic outline sketch of the torsional vibration damper 3 ;
• 5 according to an enlarged section of the torsional vibration damper 3 ;
• 6 the course of different spring characteristics.

In the 1 1 shows a torsional vibration damper 1 constructed as a dual-mass flywheel, which can be used, for example, in a drive train of a motor vehicle intended for a hybrid application. The torsional vibration damper 1 comprises on the internal combustion engine side a primary mass 2, also called the input part, and on the output side, a secondary mass 3, also called the output part, which can be rotated together about an axis of rotation 4 and can be rotated to a limited extent relative to one another. Between the primary mass 2 and the secondary mass 3 , a first damper stage 6 including arc springs 5 and forming a mechanical energy accumulator is effective. The primary mass 2, together with an associated cover element 7, encloses an interior space 8 intended to accommodate the arc spring 5. Each arc spring 5 is connected with one spring end to a stop (not shown) of the primary mass 2 and with another spring end to a support flange 9, also known as the arc spring flange multi-part secondary mass 3 supported. In the event of a relative rotation between the primary mass 2 and the secondary mass 3, an elastic deformation occurs corresponding to a spring characteristic or spring constant of the arc springs 5, the bending force of which generates a restoring force which is directed towards a rest position of the primary mass 2 and the secondary mass 3.

A second damper stage 10 is provided radially below the arc springs 5, assigned to the support flange 9, which is connected in series with the first damper stage 6 and includes two lever springs 11 offset by 180° relative to one another. The lever springs 11 are fastened in a rotationally and positionally fixed manner to an output hub 13 of the secondary mass 3 by means of riveted connections 12, which hub is connected to a transmission input shaft (not shown) by means of splines, for example. Each crescent-shaped, radially prestressed lever spring 11 is assigned a support roller 9 positioned on the carrier flange 9 and on which the lever spring 11 is supported with a free end in a non-positive manner. Furthermore, each lever spring 11 is in an operative connection with a rotatable support roller 14 positioned on the carrier flange 9 and also referred to as a roller bearing. For this purpose, the lever springs 11 and the support rollers 9 are positioned in such a way that when there is a relative movement or angular displacement between the output hub 13 and the carrier flange 9 , both support rollers 9 move along the lever springs 11 . The elastic lever springs 11 each generate a bending force according to their spring characteristic, which leads to a restoring force which acts on the carrier flange 9 and the output hub 13 of the secondary mass 3 in the direction of a rest position. The slope of the spring characteristic of the lever springs 11 is determined by their radius of curvature and also depends on the deformation per twisting angle when rolling on the associated support roller 14. In the operating state, with a relative twisting between the primary mass 2 and the secondary mass 3, the structure of the two damper stages 6 , 10 enclosing torsional vibration damper 1, the arc springs 5 as well as the lever springs 11 synchronously elastically deformed. The combination of arc springs 5 and lever springs 11 of the damper stages 6, 10 arranged in series leads to an extended, doubled spring characteristic, also known as the torsional characteristic.

The support flange 9 is supported radially on the inside on a holding element 15 and is guided axially on the primary mass 2 by means of a friction element 19 . A folded sheet metal disc is provided as the holding element 15 and is fixed to the primary mass 2 by means of screws 16, with which the torsional vibration damper 1 is simultaneously screwed to a crankshaft (not shown) of the internal combustion engine. To achieve a basic friction or basic hysteresis with a rotation between the A plate spring diaphragm 17 is used in the primary mass 2 and the secondary mass 3 . The disk spring membrane 17 fastened radially on the inside by means of the rivet connections 12 to the output hub 13 is supported on the outside via a friction disc 18 on the inside of the cover element 7 .

the 2 clarifies the structure of the torsional vibration damper 1 in a schematic outline sketch. According to this arrangement principle, in which a torque flow occurs in the direction of the arrow, all components of the torsional vibration damper 1 used between a crankshaft 20 of the internal combustion engine and a transmission input shaft 22 are arranged in a line. The two damper stages 6, 10 are arranged in a series connection between the primary mass 2 connected to the crankshaft 20, the drive side, and the output hub 13, to which the transmission input shaft 22 is coupled. The spring accumulator-forming arc springs 5 of the damper stage 6 are supported on the primary mass 2 and the carrier flange 9 of the secondary mass 3, also called arc spring flange. The lever springs 11 fixed in position on the output hub 13 are in a non-positive operative connection via a radius of curvature with the supporting rollers 14 rotatably fastened to the carrier flange 9 .

In the 3 the torsional vibration damper 21 is shown, which in addition to the in 1 shown torsional vibration damper 1 includes a centrifugal pendulum 23. All other components match the torsional vibration damper 1 and are therefore not described. The centrifugal pendulum 23 is positioned axially in front of the cover element 7 on the output side and is connected to the output hub 13 via a carrier element 25 and fastened by means of the riveted connections 12 . The centrifugal pendulum 23 of conventional design and known mode of operation enables a relative movement or oscillation of pendulum assemblies 24 in relation to the carrier element 25 in the operating state in the event of a rotational non-uniformity triggered by the internal combustion engine.

the 4 shows the structure of the in 3 shown torsional vibration damper 21. The second embodiment is compared to the torsional vibration damper 1 by the output hub 13 associated centrifugal pendulum 23 supplemented.

In the 5 an enlarged detail of the torsional vibration damper 21 is shown, showing the support bearing 26 via which the carrier flange 9 is movably supported radially on the holding element 15 and consequently the primary mass 2 . The support bearing 26 comprises a plain bearing 27 designed as a plain bearing bush with a flange 28 directed radially outwards, which is placed between the carrier flange 9 and the friction element 19 .

the 6 shows in a diagram a comparison of torsion and spring characteristics of differently constructed torsional vibration dampers, with the ordinate indicating the torque Nm and the abscissa indicating the torsional angle Φ of the torsional vibration damper. The spring characteristic 30 results for a single-stage arc spring damper. The spring characteristic 40 can be represented with a two-stage arc spring damper and the spring characteristic 50 with a torsional vibration damper including lever springs. The extended spring characteristic 60 can be realized with the torsional vibration damper 1, 21, which provides for the combination of damper stages 6, 10 with different, elastically deformable energy stores.

Reference List

1

torsional vibration damper

2

primary mass

3

secondary mass

4

axis of rotation

5

arc spring

6

Damper stage (first)

7

cover element

8th

inner space

9

beam flange

10

damper stage (second)

11

lever spring

12

rivet connection

13

output hub

14

support roller

15

holding element

16

screw

17

disc spring membrane

18

friction disc

19

friction element

20

crankshaft

21

torsional vibration damper

22

transmission input shaft

23

centrifugal pendulum

24

pendulum package

25

carrier element

26

support bearing

27

bearings

28

board

30

Spring characteristic (single-stage arc spring)

40

Spring characteristic (two-stage arc spring)

50

Spring characteristic (lever spring)

60

Spring characteristic (arc spring and lever spring combined)

Nm

torque

Φ

twist angle

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102012202255 A1 [0003]
• FR 3069603 A1 [0004]

Claims (10)

Torsional vibration damper (1, 21), which is constructed as a dual-mass flywheel and can be used in a drive train of a motor vehicle, comprising a primary mass (2) and a secondary mass (3) which can be rotated together and rotated to a limited extent relative to one another, and between which a damper stage (6th ) whose arc springs (5) are supported on the primary mass (2) and a support flange (9) of the secondary mass (3) and elastic deformation takes place in accordance with a spring characteristic of the arc springs (5), characterized in that at least one lever spring (11) enclosing further damper stage (10) is arranged in series with the first damper stage (6), the lever springs (11) being inserted between the support flange (9) and an output hub (13) of the secondary mass (3), whose elastic deformation takes place according to a spring characteristic of the lever springs (11). Torsional vibration dampers (1, 21). claim 1 , characterized in that a spring characteristic or torsional characteristic of ≥ 110° for the torsional vibration damper (1, 21) can be realized through the combination of the two damper stages (6, 10). Torsional vibration damper (1, 21) according to one of the preceding claims, characterized in that two lever springs (11) rotationally fixed offset on an output hub (13) of the secondary mass (3) each have a free end with a support roller rotatably arranged on the carrier flange (9). (14) are in an operative connection. Torsional vibration dampers (1, 21). claim 3 , characterized in that the lever springs (11) positioned offset from one another by, for example, 180° are each supported on a roller bearing assigned to the carrier flange (9). Torsional vibration damper (1, 21) according to one of the preceding claims, characterized in that the two damper stages (6, 10) used in combination produce a spring characteristic curve, which is represented by arc springs (5) and lever springs (11) with corresponding spring characteristic curves. Torsional vibration damper (1, 21) according to one of the preceding claims, characterized in that each lever spring (11) is assigned a stop to limit angular deflections of the torsional vibration damper (1, 21). Torsional vibration damper (1, 21) according to one of the preceding claims, characterized in that the carrier flange (9) is supported radially on the inside by a retaining element (15) fastened to the primary mass (2) and by a connecting element between the carrier flange (9) and the primary mass ( 2) the friction element (19) used is guided axially. Torsional vibration dampers (1, 21). claim 7 , characterized in that arranged on the holding element (15) is a support bearing (26) which is designed as a slide bearing or roller bearing and is intended to support the carrier flange (9). Torsional vibration damper (21) according to one of the preceding claims, characterized in that a centrifugal pendulum (23) positioned axially in front of the torsional vibration damper (21) on the output side is connected directly to the output hub (13). Torsional vibration damper (1, 21) according to one of the preceding claims, characterized in that a plate spring membrane (17) fixed in position on the output hub (13) is supported on the inside on a cover element (7) of the primary mass (2).

Images