centrifugal pendulum device

Abstract

Centrifugal pendulum device (1) of a torsional vibration damper, comprising at least one support flange (2) rotating about an axis of rotation, to which pendulum masses (4, 5) are assigned circumferentially distributed, which are movably articulated via rollers (7) guided in cam tracks (9) of the at least one support flange (2) and in guide tracks (8) of the pendulum masses (4, 5), and a friction shoe (10, 11) is provided as a friction medium between the pendulum masses (4, 5) and the at least one support flange (2), which is supported on the at least one support flange (2) by means of a spring element and is fixed in position within the pendulum mass (4, 5), characterized in that a coefficient of friction is established between the contact surfaces (15, 16) of the friction partners, the at least one support flange (2) and the friction shoe (10, 11) starting from a neutral or center position of the pendulum masses (4, 5). direction of a maximum oscillation angle (Σ) of the pendulum masses (4, 5) increased.

Description

The invention relates to a centrifugal pendulum device of a torsional vibration damper, comprising at least one carrier flange rotating about an axis of rotation, to which pendulum masses are assigned in a circumferentially distributed manner, which pendulum masses are articulated movably via rollers guided in link tracks of the at least one carrier flange and in guide tracks of the pendulum masses, and a friction shoe is provided between the pendulum masses and the at least one carrier flange as a friction means, which friction shoe is supported in each case in the pendulum mass in a positionally fixed manner by means of a spring element on the at least one carrier flange.In vehicles which are driven with internal combustion engines, a discontinuous torque is transmitted from the crankshaft to the drive train due to the design or through the functioning of the internal combustion engine. As a result, torsional vibrations occur, for the damping of which torsional vibration dampers are used in conjunction with a centrifugal pendulum device (FKP). The vibration energy is damped or attenuated with the FKP by pendulum masses vibrating in the opposite direction to the vibrations to be attenuated.DE 10 2006 028 556 A1 discloses a centrifugal pendulum device which comprises a plurality of pendulum masses and a central carrier flange, also referred to as a pendulum flange. The flanks of the carrier flange form guide surfaces for the pendulum masses, which are arranged movably via guide rollers or rollers guided in slide tracks or guide tracks of the carrier flange and in the pendulum masses. In this case, two pendulum masses form a pendulum mass package in each case, opposite pendulum masses being connected via spacer bolts which are guided with play through openings in the carrier flange.A further centrifugal pendulum device is shown in DE 10 2009 042 836 A1 with pendulum masses arranged on both sides of the carrier flange and pivotable with respect to the latter to a limited extent. Two pendulum masses located axially opposite each other are connected via spacer bolts guided through openings in the carrier flange to form a U-shaped structural unit.For applications of centrifugal pendulum devices with large excitations of the pendulum masses, a targeted, permanent, axial friction during the operating state is desired. For this purpose, DE 10 2017 130 493 A1 discloses a centrifugal pendulum device in which the pendulum masses include a friction element designed as a friction shoe, which is supported on the carrier flange in a prestressed manner by means of a spring element. With this measure, a defined friction or frictional force between the pendulum mass and the carrier flange can be achieved.The object of the invention is to provide a centrifugal pendulum device which is functionally improved compared to the prior art and which can be easily represented and integrated into existing centrifugal pendulum layouts.This object is achieved by means of a centrifugal pendulum device which is constructed according to the features of claim 1. Advantageous embodiments are given in the dependent claims.According to the invention, it is provided that a coefficient of friction or a frictional force increases in the direction of a maximum oscillation angle of the pendulum masses between the contact surfaces of the friction partners, the at least one carrier flange and the friction shoe, starting from a neutral or central position of the pendulum mass.With the solution according to the invention to the object, according to which a change in the coefficients of friction or the friction partners occurs in both directions of the pendulum masses at large angles of oscillation, advantageously increased frictional forces can be realized in specific operating ranges of the internal combustion engine. This applies, for example, to the start and stop phases in which large oscillation angles of the pendulum masses have previously been established. The invention achieves an increased end position friction, whereby excitations or excursions of the pendulum masses, which advantageously extend as far as the end stops, are avoided and a noise development associated therewith and an increased wear or impact energies are reduced.The design concept of the invention ensures optimum insulation in that, in particular, sprung friction shoes always slide back and forth on the same path of a contact surface. This results in permanent axial friction which does not exceed a defined value in the normal operating state. The coefficient of friction is designed such that it does not adversely affect the mode of action of the centrifugal pendulum device at small and medium angles of oscillation of the pendulum masses.According to a preferred embodiment of the invention, the coefficient of friction of the contact surfaces determined for the neutral or central position of the pendulum masses is limited to a fixed oscillation angle of the pendulum masses determined, for example, by simulation for the relevant internal combustion engine. The zone with a relatively low coefficient of friction is adjoined between the contact surfaces by a region with a changed, higher coefficient of friction. Preferably, according to the invention, instead of a stepped transition of the coefficients of friction, a continuously increasing coefficient of friction is provided in the direction of the maximum oscillation angle of the pendulum masses.Furthermore, the invention can be transferred to a centrifugal pendulum device in which the pendulum masses are arranged between two carrier flanges axially spaced parallel to one another. Each pendulum mass is preferably assigned two friction shoes on both sides, which are supported by the associated carrier flange in a force-fitting manner on an inner side via disk-like regions in order to bring about friction between the contact surfaces.The rotationally symmetrically designed friction shoe used according to the invention engages with a protruding section in a receptacle of the pendulum mass. The friction shoe forms a plate-like region in the direction of the section, which is supported directly or indirectly on the carrier flange by a spring means preferably embodied as a disk spring, for example via a friction lining. The friction shoes, which are preferably made of a metallic material, produce a permanent uniform friction when the pendulum masses are displaced and at the same time effect a centering. As an alternative to metal, a friction shoe made of a wear-resistant, permanently heat-resistant plastic can also be used.According to an advantageous embodiment of the friction shoe, its associated protruding cylindrical section enclosed by a sleeve is inserted into the receptacle of the pendulum mass designed as a bore. The sleeve, also referred to as a bushing, serves for guiding and also for optimizing the noise and friction of the friction shoe and consequently of the centrifugal pendulum device. The friction shoe is guided over the plate-like region in a sliding or frictional force-fit manner on the contact surface of the carrier flange. A disk spring which surrounds the cylindrical section of the friction shoe and presses the disk-like region of the friction shoe against the carrier flange is preferably suitable as spring means. Alternatively to a disk spring, a compression spring or corrugated spring can also be used as spring element.In order to achieve a change in coefficient of friction or a higher coefficient of friction at the contact surface of the carrier flange in the region which is intended for larger oscillation angles of the pendulum masses, the invention includes different measures in order to ensure the associated energy conversion into heat. This axial friction can be generated by various possibilities. As an alternative to friction shoes, it is possible to use one-sided or double-sided friction rings, disk springs or sprung clips. A higher coefficient of friction is also achievable by means of sliding elements locally inserted into the contact surface of the carrier flange, the sliding or friction elements being produced from a suitable material which increases the friction. The sliding elements, which are designed, for example, in different geometric shapes, can also be inserted into corresponding recesses of the contact surface of the carrier flange, arranged so as to be radially offset with respect to one another.For friction partners produced from a matching material, there is alternatively the possibility of creating a surface structure with a higher coefficient of friction starting from a defined swing angle by means of processing for the contact surface of the carrier flange.Mechanical processing of the contact surface can be carried out, for example, by means of punching, embossing, turning or milling, in order to produce a rough, in particular knurled, surface structure of the contact surface from the carrier flange in a targeted local manner, as a result of which, for example, toothing effects are produced between the sliding partners.As a further possibility for the presentation of an increase in frictional force, the invention includes a combination of different materials and a differing surface structure in the region of the large oscillation angles of the contact surfaces. In addition, a higher coefficient of friction can be achieved by virtue of the relevant zones of carrier flange contact surfaces having a friction-enhancing coating.The invention is described in more detail below with reference to an exemplary embodiment depicted in six figures. However, the invention is not limited to the embodiment shown in the figures. It shows: FIG. 1 : shows a schematic partial sectional illustration of a centrifugal pendulum device; FIG. 2 is a sectional view through a carrier flange with associated pendulum masses and friction shoes; FIG. 3 : a perspective view of partial regions of the centrifugal pendulum device; FIG. 4 is an individual part drawing of the carrier flange; FIG. 5 : partial regions of the carrier flange and the pendulum masses in a 0° oscillation angle position; FIG. 6 : partial regions of the carrier flange and the pendulum masses in a maximum oscillation angle position.FIG. 1 shows a centrifugal pendulum device 1, which is assigned in particular to a torsional vibration damper (not shown), also called a dual-mass flywheel (ZMS), of a drive train of an internal combustion engine-driven motor vehicle. The centrifugal pendulum device 1 comprises a carrier flange 2 which rotates about an axis of rotation and is associated with a component of the torsional vibration damper and is also referred to as a carrier flange and is intended to receive a plurality of pendulum mass packages 3 arranged one behind the other in the circumferential direction. Each pendulum mass package 3 consists of two identically dimensioned pendulum masses 4, 5 which are arranged at a distance from the carrier flange 3 on both sides and which are rigidly connected via spacer bolts 6 to form a unit. In the operating state, the centrifugal pendulum 1 of conventional construction and known mode of operation permits a relative movement or oscillation of the pendulum masses 4, 5 with respect to the carrier flange 2 in the event of a rotational non-uniformity initiated by the internal combustion engine. As an alternative to the centrifugal pendulum device 1 shown in FIG. 1, an alternative variant can include two carrier flanges arranged parallel to one another and rigidly connected to one another, between which the pendulum masses are arranged movably in a circumferential manner.FIG. 2 shows the carrier flange 2 in a sectional view with pendulum masses 4, 5 arranged on both sides, which are arranged in a pendulum fashion or movable relative to the carrier flange 2 by means of the roller 7. Furthermore, each pendulum mass 4, 5 is indirectly connected to the carrier flange 2 via at least one friction means embodied as a friction shoe 10, 11. Each friction shoe 10, 11 engages with an axially projecting portion 12 in a receptacle 13 of the pendulum mass 4, 5. For this purpose, the section 12 is surrounded by a disk spring 17 which is supported axially between the inner side of the dispensing cup 4, 5 and the disk-like region 14 of the friction shoe 10, 11. In contrast to the disk-like region 14 configured as a circular disk, it can also be configured in a geometric shape deviating therefrom. This also applies to the section 12 of the one-piece friction shoe 10, 11 designed as a cylinder. In particular for the purpose of optimizing noise, the section 12 of the friction shoe 10, 11 inserted into the receptacle 13 of the pendulum mass 4, 5 is surrounded by a sleeve 18 made of plastic or a metal. Friction shoes 10, 11 forming the friction means and also called clip are placed in such a way as to bring about a defined constant friction between the contact surfaces 15, 16 of the carrier flange 2 and the pendulum masses 4, 5.FIGS. 3 to 6 show in particular the structure of an end position friction according to the invention, with which an increase in frictional force can be achieved at large swing angles of the pendulum masses. Identical reference numerals are used for components which correspond to or act identically to FIGS. 1 and 2. For a better understanding of the invention, the carrier flange is depicted in FIGS. 3, 5 and 6 without front pendulum masses.In order to achieve the desired increase in frictional force at large oscillation angles of the pendulum masses 4, 5, also called oscillation deflections, the contact surface 15 of the carrier flange 2 has local sliding elements 19 with higher coefficients of friction. In FIG. 3, the centrifugal pendulum device 1 is shown in a 0° oscillation angle position, illustrated by a central position of the spacer bolts 6 and of the clip or of the friction shoes 10. The sliding elements 19 forming separate components, for example inserted into depth-limited bores 21, have a higher coefficient of friction than the carrier flange 2. The single-part drawing according to FIG. 4 shows the carrier flange 2 completely with all the sliding elements 19 arranged in the outer region.FIGS. 5 and 6 show the pendulum masses 4 in different oscillation angle positions. FIG. 5 illustrates a 0° pendulum position in which both friction shoes 11 of the pendulum mass 4 are arranged in each case centrally between the friction zones 20 of the carrier flange 2. The position shown in FIG. 6 assumes the pendulum masses 4 upon reaching the maximum oscillation angle position, caused by a relative movement in the direction of the arrow with respect to the carrier flange 2. The production of the friction zones 20 can be effected by means of local mechanical processing of the contact surface 16, for example by punching, embossing, turning or milling, in order to produce a specifically rough, in particular knurled, surface structure having a higher coefficient of friction.List of reference characters1 Centrifugal pendulum device 2 Carrier flange 3 Pendulum mass package 4 Pendulum mass 5 Pendulum mass 6 Spacer bolt 7 Roller 8 Guide track 9 Link track 10 Friction shoe 11 Friction shoe 12 Section 13 Receptacle 14 Region 15 Contact surface 16 Contact surface 17 Disk spring 18 Sleeve 19 Sliding element 20 Friction zone 21 Bore α Angle of oscillation

Claims

Centrifugal pendulum device (1) of a torsional vibration damper, comprising at least one carrier flange (2) rotating about an axis of rotation, to which pendulum masses (4, 5) are allocated in a circumferential manner, which are articulated in a movable manner via rollers (7) guided in link tracks (9) of the at least one carrier flange (2) and in guide tracks (8) of the pendulum masses (4, 5), and a friction shoe (10, 11) is provided as friction means between the pendulum masses (4, 5) and the at least one carrier flange (2), which friction shoe is supported on the at least one carrier flange (2) in each case in the pendulum mass (4, 5) in a positionally fixed manner by means of a spring element, characterized in that, starting from a neutral or central position of the pendulum masses (4, between contact surfaces (15, 16) of the friction partners, the at least one carrier flange (2) and the friction shoe (10, 11), 5) increases a coefficient of friction in the direction of a maximum oscillation angle (α) of the pendulum masses (4, 5).Centrifugal pendulum device (1) according to Claim 1, characterized in that the coefficient of friction between the contact surfaces (15, 16) of the friction partners changes from a defined oscillation angle corresponding to the central position of the pendulum masses (4, 5).Centrifugal pendulum device (1) according to Claim 1, characterized in that the coefficient of friction between the contact surfaces (15, 16) of the friction partners increases continuously starting from a central position of the pendulum masses (4, 5) until a maximum oscillation angle (α) is reached.Centrifugal pendulum device according to one of the preceding claims, characterized in that the pendulum masses are arranged between two carrier flanges (2) which are axially spaced apart parallel to one another, wherein friction shoes (10, 11) arranged on both sides of the pendulum masses are supported in a force-fitting manner on the associated carrier flange (2) via plate-like regions (14).Centrifugal pendulum device according to one of the preceding claims, characterized in that the friction shoe (10, 11) engages with a protruding section (12) in a receptacle (13) of the pendulum mass (4, 5) and is supported directly or indirectly on the carrier flange (2) via a plate-like region (14).Centrifugal pendulum device according to claim 5, characterised in that a disk spring (17) is positioned on the protruding section (12) of the friction shoe (10, 11), which is axially supported in each case in a force-fit manner between an inner side of the pendulum mass (4, 5) and the disk-like region (14) of the friction shoe (10, 11).Centrifugal pendulum device according to one of the preceding claims, characterized in that, in order to achieve a higher coefficient of friction, sliding elements (19) are locally inserted into the contact surfaces (15, 16) of the carrier flange (2).Centrifugal pendulum device according to claim 7, characterised in that several sliding elements (19) of identical or different design are inserted into corresponding recesses or bores (21) in the contact surfaces (15, 16) of the carrier flange (2).Centrifugal pendulum device according to one of the preceding claims, characterized in that the contact surfaces (15, 16) of the carrier flange (2) have friction zones (20) which are locally specifically processed in order to increase the friction force.Centrifugal pendulum device according to one of the preceding claims, characterized in that the contact surfaces (15, 16) on the carrier flange (2) in a zone of max. The oscillating angle (α) of the pendulum masses (4, 5) may have a friction-increasing coating.

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