Friction damper

Abstract

Friction damper comprising an annular housing (2) with a circumferential receiving space (3) in which at least one friction element (4) is received, which is spring-loaded in friction contact with the housing (2), characterized in that the at least one friction element (4) is designed as a spring element and is spring-loaded axially against friction surfaces (12, 13) of the housing (2).

Description

[0001] The invention relates to a friction damper comprising an annular disk-shaped housing with a circumferential receiving space in which at least one friction element is received, which is spring-loaded against the housing in frictional contact.

[0002] Devices for influencing vibrations arising in a rotating system, for example vibrations of a crankshaft of an internal combustion engine, are known, for example, from EP 1 775 496 A2 or US 2023 048844 A.

[0003] One embodiment of such a device is a friction damper, which serves to reduce vibrations in the system, for example, the vibrations of the crankshaft of an internal combustion engine. Such a friction damper comprises an annular housing, which can also be referred to as the primary side, and which is connected to the rotating shaft, for example, the crankshaft. At least one friction element is housed within the housing, with several individual friction elements typically arranged in a ring. The individual friction elements are preloaded against each other by circumferentially acting spring elements and are thereby compressed radially outwards against a radial friction surface, i.e., the inner circumference of the housing.During operation, centrifugal force presses the friction elements outwards against the friction surface, which may have a friction lining (or may be integrated directly into the friction elements). This generates the frictional torque between the housing and the friction elements, i.e., the primary and secondary sides. To prevent the friction elements from losing contact with the friction surface under the influence of gravity, integrated spring elements provide radial preload. The tangential preload of these spring elements creates a normal force between the friction elements and the primary mass, a force that is independent of rotational speed. This increases the frictional torque between the primary and secondary sides.

[0004] Typically, several individual friction elements, for example four friction elements, as well as several spring elements, in this example four spring elements, for instance in the form of coil springs, are used. This means that a large number of components, in this example eight individual parts, must be integrated into the housing, with the friction elements being provided at their mutually facing ends with corresponding receptacles or holders for the spring elements. The construction of such a friction damper is therefore complex and time-consuming.

[0005] The invention is based on the problem of providing a simpler design for a friction damper.

[0006] To solve the problem, in a friction damper of the type mentioned above, it is provided according to the invention that the at least one friction element is designed as a spring element and is spring-loaded axially against friction surfaces of the housing.

[0007] The invention is characterized by integrating the function of a spring element used in the prior art, which serves to preload the friction elements against the housing, into the at least one friction element, thus eliminating the need for a separate spring element. The at least one friction element is characterized by a dual function: firstly, its friction function relative to the housing, and secondly, its spring function to generate a corresponding, in this case axial, preload force against the housing. This axial preload force, resulting from the spring properties or the design of the spring characteristics of the friction element, allows for the realization of a speed-independent friction component without the need for an additional spring element.In the simplest case, the function of the friction damper is therefore realized by only two components: firstly, the ring-shaped housing, and secondly, at least one friction element.

[0008] In principle, only a single friction element with an integrated spring function can be provided. This element, which will be discussed further below, is, for example, ring-shaped and mounted in the receiving space with a 360° circumference. Alternatively, it is also conceivable that several separate friction elements, designed as spring elements, are mounted in the receiving space and each is spring-loaded against the friction surfaces of the housing. Thus, several individual friction elements designed as spring elements are distributed around the circumference of the receiving space; for example, four separate friction elements, each offset from the others by 90° and mounted in a suitable manner to ensure their positional stability (of course, fewer or more than four friction elements can also be provided).By designing the spring properties of the individual friction elements, as well as by the number of preferably symmetrically integrated friction elements, the generated preload force and thus the speed-independent friction component can be easily varied and adapted to the application.

[0009] In a specific embodiment of the at least one friction element, or each of the multiple friction elements, it can be provided that the friction element(s) is V-shaped in cross-section and has two radially outward-extending legs that are resiliently connected to each other. The radially outer ends of these legs are spring-loaded against a friction surface. The friction element(s) is thus a simply designed bent element, preferably made from a sheet of metal, and has a V-shape. It therefore has two radially outward-extending legs that are connected to each other at their inner ends, which is how the spring function is ultimately achieved. The radially outer ends of the two legs, which are pushed apart by the spring function, are correspondingly spring-loaded against two opposing friction surfaces of the housing. The design of such a spring element is therefore remarkably simple.

[0010] In one variant, each leg can be designed as a closed leg, forming a V-shape in a side view. Viewed circumferentially, the friction element is therefore already V-shaped; even in a side view, i.e., viewed axially, the friction element can be V-shaped, meaning that both legs form a closed, i.e., flat, V-shape.

[0011] Alternatively, it is conceivable that each leg has two leg sections which, in a side view, form a V-shape relative to each other. Each leg thus not only has a V-shaped basic form, but is divided into two leg sections arranged in a V-arrangement, both of which are axially spring-loaded at the friction surface.

[0012] As explained above, it is conceivable that only a single friction element is integrated into the housing or receiving space. According to one embodiment of this variant, only an annular friction element is provided, which, in cross-section, has a V-shaped profile and two radially outward-extending, resiliently connected legs, the radially outer ends of which are spring-loaded against the respective friction surface. The integration of a single annular friction element, which is axially spring-loaded against the friction surfaces with its two legs, similarly results in the generation of a speed-independent friction component, whereby, due to the closed shape of the friction element, no imbalance is introduced into the system. Such a friction element can also be easily manufactured as a formed or bent component from a suitable sheet metal part.

[0013] In principle, for all variations regarding the design of a friction element, it is conceivable that the length of the two legs of a friction element—be it a separate, single friction element rotating only through a specific angular segment, or a ring-shaped friction element—is the same. This means that the points where the frictional contact between the legs of the friction element and the friction surfaces of the housing is located lie essentially on the same radius. Alternatively, however, it is also conceivable that the length of the two legs is different. This is possible because the housing is closed on one side, except for a central bore through which the shaft passes, while on the other side it is open except for a circumferential annular collar that axially delimits the receiving space. That is to say,, that one leg is spring-loaded at the ring collar, while the other, possibly shorter, leg rests on a radially inner radius on the other side of the disc.

[0014] Each leg is preferably rounded on its outer circumference, i.e., it adapts to the ring shape of the channel-like section of the receiving space, thus providing a friction surface lying on a defined radius.

[0015] As previously described, the friction element(s) is preferably formed from a bent metal sheet, e.g., spring steel. During the manufacture of a friction element, the metal sheet can be easily punched into a suitable shape to form a blank, followed by a bending step in which the punched metal sheet is bent along a defined bend line so that the two resulting legs are brought together. The bend can be relatively sharp, almost like a kink, or it can be rounded. However, the bend is always executed in such a way that the two legs form a V-shape and can therefore be bent further against each other during assembly, so that in the final assembly position, the two leg ends are axially clamped against the friction surfaces.

[0016] Since a defined friction coefficient is to be generated via the friction elements, meaning that a defined friction should occur during relative movement of the friction element(s) to the housing, it is conceivable to provide a friction lining at the end of each leg that is in contact with the friction surface. This friction lining consists of a suitable friction material and is applied to the respective leg end, for example, by gluing or sintering. By selecting the material of the friction lining and the axial preload, the friction coefficient can be optimally adjusted, independent of the rotational speed.

[0017] The function of the friction damper is based on the fact that, to dampen a vibration, the friction element(s) move relative to the housing in the circumferential direction, albeit only a minimal distance, thereby generating friction. It is conceivable that the friction element(s) can be supported or guided radially at their inner end on an axially extending annular flange of the housing, which is provided on the inner circumference of the housing. Alternatively, it is conceivable that each friction element is supported at a radially inner end on a radial bearing located in the receiving space. The axially extending annular flange on the inner circumference of the housing thus serves as a bearing seat for a radial bearing against which the friction element(s) are supported at their inner end, so that in this area, no friction, which represents an undefined frictional component, ultimately occurs during relative movement.

[0018] The invention is explained below with reference to exemplary embodiments and the drawings. The drawings are schematic representations and show: Fig. 1 a schematic representation of a friction damper of a first embodiment according to the invention in a sectional partial view, Fig. 2 a side view of the friction damper made of Fig. 1, Fig. 3. A schematic diagram to explain the manufacture of a friction element of the friction damper. Fig. 1, Fig. 4 a schematic representation concerning the manufacture of a friction element of a further embodiment for a friction damper made of Fig. 1, Fig. 5 a schematic representation of a friction damper of a second embodiment according to the invention in a sectional partial view, Fig. 6 a side view of the friction damper made of Fig. 5, Fig. 7 a schematic representation of a friction damper of a third embodiment according to the invention in a sectional partial view, Fig. 8 a side view of the friction damper made of Fig. 7, and Fig. 9 a schematic representation concerning the manufacture of a friction element of the friction damper made of Fig. 7.

[0019] Fig. Figure 1 shows a schematic representation in the form of a partial view of a friction damper 1 according to the invention, comprising an annular disk-shaped housing 2 (see also Figure 1). Fig. 2), which has a receiving space 3 for several friction elements 4, which are equidistantly distributed in the receiving space 3 in the circumferential direction. The housing 2 has an annular housing wall 5, to which an axially extending annular flange 6 is attached radially inside and to whose outer circumference an outer annular flange 7, also extending radially, is attached. The annular flange 7 transitions into a radially extending annular collar 8, so that the receiving space 3 is bounded by this.

[0020] Each friction element 4 is also designed as a spring element. It has two legs 9, 10 formed by bending a stamped metal blank, which are connected to each other at their inner ends via a resilient connecting section 11. Due to this spring property, the two axially outer ends of the legs 9, 10 are each spring-loaded against a friction surface 12, 13 of the housing 2, with leg 9 springing at its outer end against the friction surface 12, which is formed on the axial inner surface of the ring collar 8, while leg 10 springs at its outer end axially against the friction surface 13, which is formed on the inner side of the housing wall 5. The spring action and the resulting axial preload force are represented by the two arrows P1. Each friction element 4 is dimensioned in length such that it extends into the receiving space orThe friction elements 4 can be inserted into the undercut outer ring channel, but cannot detach themselves from it automatically. During operation, the friction elements 4 are driven radially outwards by centrifugal force, i.e., they are displaced radially a short distance so that they do not bear against the ring flange 6 in the region of their inner end.

[0021] As described, in the example shown, four individual friction elements 4 are mounted equidistantly distributed in the receiving chamber 3, so that an imbalance-free arrangement is achieved if the friction elements 4 are identical in design. All friction elements 4 are axially clamped with their corresponding legs, resulting in a speed-independent friction component that is part of the total friction of the damping system. During operation, when the friction damper 1 is mounted on a shaft 14 exhibiting torsional vibrations, which is in Fig. 1 is only indicated, is arranged, the torsional vibrations result in a relative movement of the friction elements 4 relative to the housing 2 and ultimately in friction, resulting from the axial tension of the friction elements 4 and thus in vibration damping.

[0022] The friction damper 1 according to the invention therefore ultimately consists of only a very few elements, namely the housing 2 and the friction elements 4, and is very simple and compact in its construction. This is because the friction elements 4 have a dual function. Firstly, they generate friction, and secondly, they act as a spring element, resulting from their integrated spring properties, which generate the axial preload force.

[0023] Fig. Figure 3 shows a schematic diagram of how a friction element 4, as it is used in the Fig. 1 and Fig. As shown in Figure 2, a stamped part 15 is produced from a metal sheet. This part already has the two legs 9, 10, which are connected to each other along a bending line 16. In this example, friction linings 23 are already applied to the ends of the two legs 9, 10, e.g., glued or otherwise attached, and these linings are in contact with the respective friction surfaces 12, 13 in the assembled position. In the next step, see arrow P2, the two legs 9, 10 are then bent relative to each other around the bending line 16, forming the connecting section 11, so that the part shown in Figure 2 is formed. Fig. 3 or Fig. The friction element 4 shown in Figure 1 is formed. The two legs 9, 10 are clearly curved at their outer ends, following the ring shape of the annular channel in the receiving space 3, which is located radially outside. The friction element 4 is formed in the Fig. The friction element 4 shown in Figures 1-3 each has closed legs 9, 10 which are V-shaped in the side view (see the Fig. 2 and Fig. 3), and which are also v-shaped in cross-section (see Fig. 1).

[0024] Fig. 4 shows a representation similar to Fig. 3, i.e., how to manufacture a friction element 4. This friction element 4 differs in its shape from the friction element 4 according to the Fig. 1 - 3.

[0025] The starting point here is again a stamped part 15 made of a metal sheet, to which the two legs 9, 10 are formed. In this variant, each leg 9, 10 has two leg sections 9a and 10a, respectively, which diverge in a V-shape and at whose ends friction linings 23 are applied, as an example. The two legs 9, 10 are connected to each other by a bend line 16, around which, as shown by arrow P2, the two legs 9, 10 are bent towards each other again so that they are congruent. In this variant, each leg 9, 10 therefore rests with the outer ends of the two leg sections 9a and 10a against the friction surfaces 12, 13. The friction surface is smaller here than in the embodiment according to Fig. 3, the friction component can be adjusted accordingly via the width and thus the individual contact surfaces of the leg sections 9a and 10a.

[0026] The Fig. 5 and Fig. Figure 6 shows a further embodiment of a friction damper 1 according to the invention, again comprising a housing 2 with a receiving chamber 3 in which several individual friction elements 4 are received. The construction of the housing 2 corresponds to that shown in Figure 6. Fig. 1 described, therefore reference is made to the relevant description.

[0027] The friction elements 4 also correspond to the friction elements 4 as in the Fig. 1-3 shown and described, but could also be the variant according to Fig. 4 correspond. They are each V-shaped and have two legs 9, 10 which are axially spring-loaded at their outer ends against the corresponding friction surfaces 12, 13. The spring action is also achieved here via the resilient connecting section 11.

[0028] Unlike the embodiment according to Fig. Here, a radial bearing 17 is arranged on the inner ring flange 6, the ring flange 6 consequently serving as a bearing seat for the radial bearing 17, which is fixed there with its inner ring 18. The respective friction element 4 is radially supported and guided on the outer ring 19, with this guidance ultimately being frictionless.

[0029] The Fig. Figures 7-9 show another embodiment of a friction damper 1. This one features, see Fig. Figure 7 again features a housing 2, which has a receiving chamber 3, in which, however, only a single friction element 4 is received. The housing 4 is also annular in shape; in this example, it only has the housing wall 5 and the ring flange 7 with the ring collar 8. The single friction element 4 is also ring-shaped. It again has two legs 9, 10, which are axially spring-loaded against the friction surfaces 12 on the ring collar 8 and 13 on the housing wall 5, respectively, as indicated by arrows P1. The legs 9, 10 are connected to each other via the spring-loaded connecting section 11.

[0030] Fig.Figure 9 shows an exemplary production of the ring-shaped friction element 4. Here again, a stamped metal part 15 made from a metal sheet is used, designed as a ring disc. It has a closed outer ring section 20 and an inner ring section consisting of several individual segments 21, which are separated from each other by corresponding slots 22. Along a circular bending line 16, the segments 21 are bent outwards, as indicated by arrow P2, so that together they form the leg 10. That is, in this embodiment, the leg 10 is formed from the individual segments 21. The contact surface of the leg 10 is therefore somewhat smaller than the contact surface of the leg 9. However, both legs 9 and 10 are spring-loaded against the friction surfaces 12 and 13 via the resilient connecting section 11.The width of the slots 22 allows the size of the contact area of ​​the leg 10, i.e., the segmented leg, on the friction surface 13 to be varied, and thus the speed-independent friction component can be additionally adjusted. The friction linings applied to the legs 9 and 10, if required, are not shown here, but can easily be applied to the stamped part.

[0031] Although the lengths of the two legs 9, 10 are the same in all embodiments, it is of course also conceivable to design the leg lengths differently. For example, leg 10, which rests against the friction surface 13 of the housing wall 5, can also be somewhat shorter, since it can naturally rub against the housing wall 5 at any radial position.

[0032] As described, the friction elements are formed from a suitable sheet metal part using stamping and forming processes. For example, spring steel sheet metal can be used. Reference symbol list 1 Friction damper 2 cases 3 Recording room 4 friction elements 5 Housing wall 6 ring flange 7 ring flange 8 ring bundle 9 thighs 9a thigh section 10 thighs 10a thigh section 11 Connecting section 12 friction surface 13 friction surface 14 wave 15 die-cut parts 16 Bending curve 17 radial bearings 18 inner ring 19 Outer ring 20 Ring section 21 Segment 22 slots 23 Friction lining P1 Arrow P2 arrow QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 1 775 496 A2

[0002] US 2023 048844 A

[0002]

Claims

Friction damper comprising an annular housing (2) with a circumferential receiving space (3) in which at least one friction element (4) is received, which is spring-loaded in friction contact with the housing (2), characterized in that the at least one friction element (4) is designed as a spring element and is spring-loaded axially against friction surfaces (12, 13) of the housing (2). Friction damper according to claim 1, characterized in that several separate friction elements (4) designed as spring elements are received in the receiving space (3) and are each spring-loaded against the friction surfaces (12, 13) of the housing (2). Friction damper according to claim 1 or 2, characterized in that the friction element or each friction element (4) is V-shaped in cross-section and has two radially outwardly extending legs (9, 10) which are resiliently connected to each other and which are spring-loaded at their radially outer ends to a friction surface (12, 13). Friction damper according to claim 3, characterized in that each leg (9, 10) is designed as a closed leg (9, 10) in a side view V-shaped, or that each leg (9, 10) has two leg sections (9a, 10a) which run in a V-shape to each other in a side view. Friction damper according to claim 1, characterized in that only one ring-shaped friction element (4) is provided, which in cross-section is V-shaped and has two radially outwardly extending legs (9, 10) which are resiliently connected to each other and which are spring-loaded at their radially outer ends on the respective friction surface (12, 13). Friction damper according to one of the preceding claims, characterized in that the length of the two legs (9, 10) of a friction element (4) is the same or different. Friction damper according to one of the preceding claims, characterized in that each leg (9, 10) is rounded on its outer circumference. Friction damper according to one of the preceding claims, characterized in that the friction element or elements (4) consists of a bent metal sheet. Friction damper according to one of the preceding claims, characterized in that a friction lining (23) is provided at the end of each leg (9, 10), which is in contact with the friction surface (12, 13). Friction damper according to one of the preceding claims, characterized in that the friction element or each friction element (4) is supported with a radially inner end on a radial bearing (17) which is arranged in the receiving space (3).

Images