Torsional damper

Abstract

A damper (1) comprising a hub (2) with a longitudinal axis (A) defining an internal portion (2') designed to be connected to a hub (3) dragged by a shaft rotating around said axis (A), an external portion (2'') defining an engagement portion (5) designed to cooperate with an endless transmission element and an intermediate portion (2''') connecting said internal and external portions (2'', 2'), the damper (1) comprising a damping module (10) operatively connected to one of said portions (2', 2'', 2''') so as to dampen torsional oscillations transmitted by the shaft to the endless transmission element, the hub (2) defining a plurality of openings (15), the damper (1) comprising a ventilation system (16) configured to force air to flow through said openings (15) towards or from said damping module (10).

Description

[0001] TORSIONAL DAMPER

[0002] Cross-Reference To Related Applications

[0003] This patent application claims priority from Italian patent application no . 102024000004348 filed on February 28 , 2024 , the entire disclosure of which is incorporated herein by reference .

[0004] Technical Field

[0005] The invention relates to a damper, in particular a torsional damper .

[0006] The invention preferably, though not exclusively applies to the automotive industry . Hereinafter reference will be made to this application by mere way of example .

[0007] Known State of the Art

[0008] As it is known, the drive shaft of internal combustion engines is subj ected to torsional vibrations due to periodic stresses caused by the combustion taking place in the cylinders . Said vibrations are particularly strong when the engine is started and at low speeds as well as in the presence of particular constructive solutions , such as for example the use of dual-clutch transmissions or start-stop systems .

[0009] Torsional vibrations translate into irregularities in the rotation of he drive pulley of the accessory transmission, which are transmitted to the accessories through the transmission belt , which, therefore , is subj ected to periodic tension vibrations .

[0010] It is therefore known, in the automotive industry, to reduce the amplitude of the torsional vibrations of the drive shaft through the use of filtering assemblies , such as torsional dampers , which are distinguished based on their operating principle, namely based on the means that is used to damp the vibrations .

[0011] Much used in the past in engines for motor vehicles were friction dampers for torsional vibrations , which, in broad terms , consist a flywheel that is caused to rotate by the drive shaft through a friction coupling; thanks to its high moment of inertia, the flywheel tends to assume a constant speed of rotation, consequently damping, by means of the friction, any torsional vibrations of the drive shaft .

[0012] For applications with higher speci fic power and for uses in motor vehicles there are provided dampers that use an elastic material or a viscoelastic fluid as a damping means , whose operating principles are similar to the one mentioned above . In the case of viscoelastic fluid dampers , the coupling between the drive shaft and the flywheel is obtained through the interposition of a viscous means , typically silicone fluid .

[0013] Optionally, said torsional dampers can be coupled to filtering pulleys that can be of various types , as it is known for example from EP 3271616 Al .

[0014] During its use , the damper tends to heat up, thus making it necessary to reduce the use of the damper or requiring a design that is such as to increase the si ze , weight and, hence , costs thereof .

[0015] Solutions are known, in which cooling fins are obtained from and carried by a portion of the damper, which, however, are not configured to permit a suf ficient cooling thereof .

[0016] Further blading solutions are known, which, however , are particularly expensive and di f ficult to produce .

[0017] The obj ect of the invention is to provide a torsional damper capable of solving the aforementioned technical problem in a simple and economic fashion .

[0018] In particular, the obj ect is to provide a damping assembly that allows the damper to be maintained within a predetermined temperature range without , however, increasing its dimensions , weight and costs , as is the case in known systems .

[0019] Summary of the Invention

[0020] The aforesaid obj ect is reached by a torsional damper and by a filtering assembly as claimed in the appended claims that are an integral part of this description .

[0021] Brief Description of the Drawings

[0022] The invention will be best understood upon perusal of the following detailed description of a preferred embodiment , which is provided by way of non-limiting example , with reference to the accompanying drawings , wherein :

[0023] • Figure 1 is a perspective view of a damper according to the invention;

[0024] • Figure 2 is a cross section view according to line I l l i of the damper of Figure 1 ;

[0025] • Figure 3 is an exploded perspective view of the damper of Figure 1 ; and

[0026] • Figure 4 is an enlarged perspective view of a portion of the damper of Figure 1 .

[0027] Detailed Description of the Invention

[0028] The accompanying figures show a damper 1 for automotive use . The damper 1 is coaxial to a longitudinal axis A and basically comprises a hub 2, in the disc-shaped embodiment, comprising an external portion 2' configured to cooperate with an endless connection element, such as a toothed belt, an internal portion 2' ' radially internal to the external portion 2' and an intermediate portion 2' ' ' connecting the external and internal portions 2' , 2' ’ to one another.

[0029] The external portion 2’ is designed for a rotating shaft (not shown) coaxial to the axis A and forming part of a powertrain system (not shown) of a vehicle.

[0030] Advantageously, the aforementioned hub 2 is manufactured as one single piece, i.e. it is monolithic.

[0031] In detail, the external portion 2’ comprises an external cylindrical wall 4 coaxial to the axis A and defining an engagement portion 5 provided with a coupling profile configured to cooperate with the aforementioned endless transmission element. For example, the coupling profile 5' is a poly-V profile for a relative toothed belt.

[0032] The external portion 2’ also comprises an external radial wall 6 configured to radially extend from one of the axial ends of the external cylindrical wall 4 towards the longitudinal axis A.

[0033] The internal portion 2’ ’ comprises an internal radial wall 7 radially extending from the hub 3 on a side that is axially opposite with respect to the external radial wall 6.

[0034] The intermediate portion 2’ ’ ’ is configured to connect the external and internal radial walls 6, 7 and, in particular, comprises an internal cylindrical portion 8 connected to the external and internal radial walls 6, 7 by respective j oining portions 8 ' , 8 ' ' .

[0035] Therefore , the hub 2 delimits a space 11 axially delimited by the external radial wall 6 and open on the opposite side and radially delimited by the external and internal cylindrical walls 4 , 8 .

[0036] The damper 1 comprises a damping module 10 housed in the space 11 and conf igured to dampen torsional oscillations at the hub 2 .

[0037] In the embodiment described herein, the damping module 10 comprises an inertial ring 12 housed in the space 11 and having an annular shape and made o f a metal material with a predefined shape and weight .

[0038] The inertial ring 12 is connected to the hub 2 so as to allow for the damping of torsional oscillations between the hub 2 and the endless transmission element connected through the engagement portion 5 .

[0039] In particular, in the embodiment described herein, the damper 1 comprises a connection portion 13 made of an elastic material , advantageously a polymer and / or elastomer and / or plastic material , which is configured to connect the inertial ring 12 to the external cylindrical wall 4 .

[0040] Alternatively, although this solution is not shown herein, the damping module 10 can comprise a housing, which is designed to support a viscous f luid and within which the inertial ring 12 could be placed in order to operatively connect it to the hub 2 so as to permit the aforementioned damping of torsional oscillations .

[0041] Advantageously, the hub 2 defines a plurality of openings

[0042] 15 configured to allow air to f low towards the space 11 through the hub 2 .

[0043] Preferably, said openings 15 are made in the external radial wall 6. Advantageously, they are arranged circumferentially around the longitudinal axis A. More speci fically, they are angularly equally spaced apart from one another around the axis A.

[0044] Advantageously, these openings 15 are quadrangular and, more in detail , rectangular with the larger edge of the rectangle facing in a circumferential direction .

[0045] The damper 1 is preferably provided with a venti lation system 16 provided with one or more blades 19 configured to force air through the openings o f the hub 2 so as to cause it to flow towards or from the damper module 10 .

[0046] Advantageously, the ventilation system 16 compri ses a plurality of blades 19 , at least one of them for each of the openings 15 .

[0047] Advantageously, the blades 19 are configured to have an inclination with respect to the external radial wall 6 . More in detail , the blades 19 extend with respect to the smaller edges of the aforementioned openings 15 .

[0048] In the embodiment described herein, each opening 15 houses a pair of blades 19 , one for each smaller side of the opening 15 . In detail , said blades are inclined contrary to one another, i . e . one facing the space 11 and one facing the external space on the side opposite the space 11 .

[0049] Advantageously, the ventilation system 16 is can selectively be fixed to the hub 2 . In detail , in the embodiment shown herein, the blades 1 are carried by an auxiliary element 17 configured to be selectively fixed to the external radial wall 6 .

[0050] In particular, said auxiliary element 17 is manufactured as one single piece with the blades 19 and has an annular shape so that it axially faces , when fixed to it , the external radial wall 6 .

[0051] In detail , the auxiliary element 17 defines a plurality of openings 18 having a shape similar, in particular identical , to that of the openings 15 and coaxial to them . Said openings 18 are provided with the aforementioned blades 19 .

[0052] In the embodiment described herein, therefore , the openings 18 have a similar shape to the openings 15 and are provided with blades 19 circumferentially extending from the opposite side with respect to one another . In detail , they are therefore carried by the smaller edges of the rectangular shape of each opening 18 .

[0053] As mentioned above , the auxiliary element 17 can be selectively fixed to the hub 2 by means of a fixing system 20 so as to place the blades 19 through the openings 18 and 15 .

[0054] In detail , the fixing system 20 comprises a snap mechanism 21 . Advantageously, the snap mechanism comprises at least one elastic wing configured to be inserted and cause the auxiliary element 17 to become integral to the hub 2 . In detail , said at least one wing is carried by one of the edges of the opening 18 and is si zed so as to snap into the openings 15 providing an axial pre-load between the auxiliary element 17 and the hub 2 , i . e . the external radial wall 6 thereof .

[0055] More in detail , according to the embodiment described herein, the snap mechanism 21 comprises a pair of wings carried by the larger edge of the openings 18 and, in particular, in the middle thereof.

[0056] As best shown in Figure 4, each blade 19 advantageously comprises a main wall 19' , which preferably is flat.

[0057] In particular, as mentioned above, said main walls 19' are inclined in an opposite direction with respect to the longitudinal axis A, in particular they have the same inclination in an opposite direction.

[0058] Advantageously, for each opening 18 / 15, one blade 19 comprises the main wall 19' extending directly from the auxiliary element 17, whereas the other blade extends starting from a projecting portion 19' ’ protruding from the auxiliary element 17.

[0059] This projecting portion 19' ’ axially extends along the axis A so as to allow the blade 19 to extend inside the opening 15 / 18. In detail, the extension of said projecting portion 19' ’ is such as to cooperate in contact with one of the edges of the openings 15, hence in contact with the external radial wall 6 so as to act as a circumferential limit stop.

[0060] The auxiliary element 17 can be made of a metal or a plastic / polymer material depending on the required design needs .

[0061] In detail, although this is not shown in the figures, the damper 1 could be part of a filtering assembly, i.e. it could be coupled to a filtering pulley (not shown) connected, for example, on the same side as the hub 2 or on the side opposite it. The operation of the embodiment of the damper according to the invention described above will be disclosed below .

[0062] During the operation of the damper 1 , in general , the torque provided by the rotating shaft to the hub 2 is transmitted to the engagement portion 5 . Possible torsional oscillations transmitted to the hub 2 are absorbed by the damping module 10 .

[0063] During the operation, i . e . the rotation of the damper 1 around the axis A, the blades 19 are configured to suck air through the openings 15 towards the damping module 10 .

[0064] Owing to the above , the advantages of a damper according to the invention are evident .

[0065] Thanks to the damper 1 disclosed herein, it is possible to ef fectively cool the inertial ring in order to reduce the design dimensions thereof , hence weight and s ize , thus allowing it to be used for as long as possible .

[0066] By reducing weight and dimensions , manufacturing costs and times are clearly reduced . Moreover, it is clear that maintaining the damper at reduced temperatures prevents the damper from wearing out when it is used for a long time .

[0067] Furthermore , the special arrangement of blades and openings allows a large amount of air to be sucked towards the inertial ring . The shape of the blades is also optimi zed to maximi ze this air flow and allow it to be sucked in both directions .

[0068] The fact that the blades are placed on a separable element that can be fixed to the hub facilitates the production of the damper as they can be produced by di f ferent production methods with consequent savings and optimisation of production times .

[0069] Furthermore , the assembly and the possible replacement of one of the two components of the damper are facilitated .

[0070] In addition, the mechanical snap connection is easy to use and safe and simple to remove in the event of a replacement or inspection .

[0071] Furthermore , the fact that one of the blades extends from a proj ecting portion that acts as a circumferential limit stop facilitates the installation of the auxiliary element so as to match the openings and the blades in the correct angular position .

[0072] Finally, the damper according to the invention can clearly be subj ected to changes and variants , which, though, do not go beyond the scope of protection set forth in the appended claims .

[0073] Clearly, as mentioned above , the damper can be isolated on the rotating shaft or be coupled to a filtering pulley or to other uncoupling elements .

[0074] Furthermore , as described above , the damper can be an elastic ring damper or a viscous damper .

[0075] Moreover, the openings disclosed herein or the blades can have a di f ferent shape or be in a number di f ferent from the one described above .

[0076] Furthermore , the auxiliary element could be absent and the blades could be integrated in the hub itsel f or it could be fixed to the hub 2 in di f ferent ways , such as for example through threaded elements , through welding or through interference .

Claims

CLAIMS1.- Damper (1) comprising a hub (2) of longitudinal axis (A) , said hub (2) defining an internal portion (2' ) capable of being dragged by a shaft rotating around said axis (A) , an external portion (2' ') defining an engagement portion (5) capable of cooperating with an endless transmission element and an intermediate portion (2' ' ') connecting said internal and external portions (2' ', 2' ) , said damper (1) comprising a dampening module (10) operatively connected to one of said portions (2 ' , 2 ' ' , 2 ' ' ' ) so as to dampen torsional oscillations transmitted by said shaft towards said endless transmission element, said hub (2) defining a plurality of first openings (15) , said damper (1) comprising a ventilation system (16) configured to force the passage of an air flow through said first openings (15) to or from said dampening module (10) , said ventilation system (16) being selectively fixable to said hub (2) .2.- Damper according to claim 1, wherein said ventilation system (16) comprises an auxiliary element (17) selectively fixable to said hub, said auxiliary element (17) comprising one or more blades (19) associated with each of said first openings (15) .3.- Damper according to claim 2, wherein said external portion (2' ) includes an external radial wall (6) , said first openings (15) being made passing through said external radial wall (6) , said auxiliary element (17) being selectively fixed to said external radial wall (6) .4.- Damper according to claim 2 or 3, wherein said auxiliary element (17) defines a plurality of second openings(18) , in use, axially facing said first openings (15) of said hub (2) , said blades (19) extending from edges of said first and second openings (18) through said openings (15, 18) .5.- Damper according to claim 4, wherein each second opening (18) is provided with two blades (19) , said blades(19) being inclined with respect to said longitudinal axis (A) , one in the opposite direction to the other.6.- Damper according to claim 5, wherein said first openings (15) have a rectangular shape, said blades (19) being associated, respectively, with the edges of smaller extension of said first openings (15) .7.- Damper according to one of claims 4 to 6, wherein said auxiliary element (17) is connected to said hub (2) via a mechanical coupling (20) .8.- Damper according to one of claims 4 to 7, wherein said auxiliary element (17) is connected to said hub (2) via a snap mechanism (21) .9.- Damper according to claim 8, wherein said snap mechanism (21) comprises at least one elastic fin carried by an edge of said second openings (18) , said elastic fin extending from said auxiliary element (17) and being suitable for cooperate with said hub (2) on the opposite side of said hub (2) to provide an axial load keeping said auxiliary element (17) in contact with said hub (2) .10.- Damper according to claim 9, wherein said at least one elastic fin is carried by an edge of said second openings (18) different from an edge supporting a blade (19) .11.- Damper according to one of claims 4 to 10, whereinat least one of said blades (19) includes a cantilevered portion (19' ' ) extending axially with respect to said longitudinal axis (A) inside said first and second openings (15 , 18) and a main portion (19' ) extending inclined with respect to said longitudinal axis (A) through said openings, said cantilevered portion (19' ' ) cooperating in contact circumferentially with one of the edges of said first and second openings (15, 18) .12.- Damper according to one of claims 2 to 11, wherein said auxiliary element (17) is made in a single piece of plastic or metallic material.13.- Damper according to one of the previous claims, wherein said dampening module (10) comprises an inertial ring (12) connected to said hub (2) via a viscous fluid system or via an elastic connection (13) .14.- Dampening assembly comprising a filtering pulley operatively connected to a damper (1) according to one of the previous claims.15.- Vehicle system comprising a damper (1) according to one of claims 1 to 13 and / or a dampening assembly according to claim 14.

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