Patent Application
20240392858
This application claims priority under 35 U.S.C. § 119 from German Patent Application No. 102023113991.6, filed May 26, 2023, the entire disclosure of which is herein expressly incorporated by reference.
The present invention relates to a torsional vibration damper having a hub part (primary mass) which can be fastened on a drive shaft of an engine and a flywheel ring (secondary mass) surrounding the hub part in the radially outer region, wherein a gap filled with a fluid and one or more sealing devices are provided between the hub part and the flywheel ring, by which the escape of the fluid is to be prevented.
A generic torsional vibration damper is known from DE 10 2020 118 066 A1. GB 11 05 292 A and WO2018/019729 A1 are also cited for the technological background.
The generic torsional vibration dampers have an outwardly offset flywheel ring, which distinguishes their design from constructions in which the flywheel ring is completely encapsulated in a separate housing.
DE 10 2020 118 066 A1 then shows torsional vibration dampers with a hub part that can be attached to a drive shaft of a motor and a flywheel ring that surrounds the hub part in the radially outer area. A gap filled with a fluid and at least one sealing device is arranged between the hub part and the flywheel ring, by means of which the escape of the fluid is to be prevented.
The sealing devices each have a first ring that is tightly connected to the hub part, hereinafter referred to as the inner ring, and a second ring that is tightly connected to the flywheel ring, hereinafter referred to as the outer ring. The sealing device also has in each case a sealing element made of an elastomer, which is connected to the inner ring in a sealing manner on the one hand and to the outer ring on the other, in particular by vulcanization. The sealing element is welded at different heights.
The solution described above has proven itself in principle. However, the provision of the plastic-metal seal described above, in particular the elastomer-metal seal with the corresponding strength in the area of the torsional vibration damper, is associated with increased costs.
The present invention therefore addresses the object of creating a more cost-optimized variant with the advantages of DE 10 2020 119 066 A1.
The invention solves this object by providing a torsional vibration damper with the features of the independent claim(s).
A torsional vibration damper according to the invention is designed with a hub part, which can be attached to a drive shaft of an engine, as the primary mass and a flywheel ring, which surrounds the hub part in the radially outer area, as the secondary mass.
A gap filled with a fluid and one or more sealing devices are provided between the hub part and the flywheel ring to prevent the fluid from escaping. The sealing device or the sealing devices each have a first ring connected to the hub part and a second ring connected to the flywheel ring, as well as a sealing element made of a plastic, in particular an elastomer.
The sealing element is arranged in each case sealingly between the first ring and the hub part on the one hand and between the second ring and the flywheel ring on the other.
The sealing element is clamped between the interconnected components, i.e. the first or second ring and the respectively associated flywheel ring or hub part. The arrangement of the sealing element between the two aforementioned components refers in particular to an arrangement in a section that extends through the axis of rotation of the torsional vibration damper.
By clamping between the respective ring and the other component of the torsional vibration damper, a flush connection of the ring with the flywheel ring or the hub part can be achieved on the one hand and a very cost-effective, time-saving and sufficiently strong connection of the components can be made possible on the other hand.
Further advantageous embodiments are the subject matter of the dependent claims.
To improve the clamping effect, it is advantageous if the sealing element has an edge-side, preferably circumferential, material bead.
In the same way, it is also advantageous if the material bead lies in a groove, preferably a circumferential groove.
The groove can advantageously be arranged in the flywheel ring or hub part.
The first ring can be advantageously flush with the hub part. The second ring can be flush with the flywheel ring. In this case, the sealing element and the ring lie in a step of the hub part and/or the flywheel ring and are flush with the outside of the respective hub part or flywheel ring.
For better insertion of the material bead, the groove has a trapezoidal cross-sectional area, for example. Alternatively, the trapezoidal cross-section can form an undercut so that the material bead is held axially in the groove with respect to the axis of rotation of the torsional vibration damper.
The connection for clamping the sealing element can be formed in particular between the first ring and the hub part or between the second ring and the flywheel ring by one or more mechanical connectors, in particular by screwing.
Alternatively or in addition to the aforementioned variant, the connection can be formed in particular between the first ring and the hub part or between the second ring and the flywheel ring by means of a materially bonded connection, in particular welding.
The material bead can be ring-shaped for sealing on all sides and preferably with a circular or ovoid cross-section. This seal enables a wide-area contact on the corresponding sealing surface of the groove and the ring.
Alternatively, the material bead can be star-shaped, preferably X-shaped. This creates several sealing lips or sealing planes. For further optimized retention of the seal under the effect of radial tensile forces, it is advantageous if the shape of the material bead is complementary to the shape of the groove. For this purpose, the torsional vibration damper can in particular have a positive fit between the material bead and the groove, which is designed as an axial stop, in particular with an undercut.
The mechanical connectors can be advantageously designed as screws, fitting bolts, bushes, preferably slotted bushes, rivets and/or clamps. The connection can be made by screwing, by press-fitting or by other means.
Furthermore, the mechanical connectors can be inserted through an opening in the sealing element, in particular in the material bead. This is an opening that is made in the material of the annular sealing element.
Preferably, the mechanical connectors or the welding are arranged outside the sealing area with the sealing element, so that there is no material weakening of the sealing element.
For a long-lasting connection, it is advantageous if the welded connection is designed as a through-welded connection through the respective ring.
Alternatively or additionally, the welded joint can be designed as a surface weld in a transition area between the respective ring and the flywheel ring or the hub part.
Preferably, a high-temperature resistant elastomer, such as EPDM or silicone material, can be used as the elastomer between the respective first and second rings of a sealing device. “Silicone material” in the context of this document means a material that contains or is a synthetic polymer in which silicon atoms are linked via oxygen atoms.
The sealing element can particularly preferably consist of an inorganically filled silicone elastomer, wherein the proportion of inorganic material is at least 30%. This is particularly useful because the materials mentioned are also suitable in high temperature ranges.
In addition, the material has little influence on the service life of silicone oil. Conversely, the material is resistant to the silicone oil and swells only slightly.
Further according to the invention is a torsional vibration damper having a hub part (primary mass) which can be fastened on a drive shaft of an engine and a flywheel ring (secondary mass) surrounding the hub part in the radially outer region, wherein a gap filled with a fluid and one or more sealing devices are provided between the hub part and the flywheel ring, by means of which the escape of the fluid is to be prevented, wherein the sealing device or the sealing devices each have at least one sealing element made of a plastic, which is arranged in each case in a sealing manner on the hub part and on the flywheel ring, wherein the sealing element is connected to the respectively associated flywheel ring or hub part by positive fit.
As in the first variant of the invention described above, the connection between the sealing element and the flywheel ring or hub part is purely mechanical and, in particular, does not require any complex electroplating.
The sealing element and the flywheel ring or the hub part can advantageously have a mutually complementary groove and a material bead, which form the positive fit.
The positive fit between the material bead and the groove can be designed as an axial stop, in particular with an undercut.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.
The torsional vibration damper having an axis of rotation 1a comprises a hub part 2 (primary mass) which can be attached to a drive shaft of an engine, a flywheel ring 3 (secondary mass) which surrounds the hub part 2 in the radially outer region, wherein a gap 4 is provided between the hub part 2 and the flywheel ring 3, which gap 4 is filled with a fluid, preferably a silicone oil, and sealing devices 5′ for sealing the gap 4 to the outside. This is an external flywheel ring 3.
Each sealing device 5′ has a first ring 6, which is tightly connected to the hub part 2, and a second ring 7, which is also tightly connected to the flywheel ring 3, as well as a sealing element 12 made of an elastomer or a TPE, which is connected to the first ring 6 in a sealing manner on the one hand and to the second ring 7 in a sealing manner on the other.
The rings 6, 7 are preferably made of metal and are firmly and tightly connected to the hub part 2 or the flywheel ring 3 by a suitable connection method, in particular screwing, welding, gluing, soldering or the like.
The respective sealing element 12 made of plastic, in particular elastomer or TPE, is connected to the two first and second rings 6, 7 in a circumferentially sealing manner. A plastic can also be an industrially modified natural product, although a silicone-based elastomer is preferred for the application due to its thermal stability.
The ring 6, ring 7 and the sealing element 12 form an assembly as a sealing device, which is also referred to as the cover 100′. The torsional vibration damper 1 has two covers 100′. The flywheel ring 3 is mounted here on plain bearings 9 in relation to the hub part 2, both radially and axially, whereby the size of the gap 4 is precisely defined.
The flywheel ring 3 preferably consists of two components in order to be able to mount this flywheel ring 3 on the hub part 2. All previously known design forms and others are possible.
In the exemplary embodiments shown, the hub part 2 is provided with a radially outwardly projecting flange 10, which is closed off in the outer edge area by a web 11 extending in the axial direction, which can extend to both sides of the flange 10, resulting in a T-shape, but can also extend to only one side of the flange 10, resulting in an L-shaped cross-section. Due to this geometry, the flywheel ring 3 is fixed relative to the hub part 2 both in the radial direction and in the axial direction, wherein, as already mentioned, the size of the circumferential gap 4 is always defined by the plain bearings 9.
The ring-shaped sealing element 12 made of plastic is simultaneously fixed to larger-surface, external axial and radial edge areas 6a, 7a of the rings 6 and 7. The edge areas 6a, 7a are thus fastening surfaces for the sealing element 12. This is described further below.
Each sealing device 5′ also consists of the first ring 6, which is tightly connected to the hub part 2, the second ring 7, which is also tightly connected to the flywheel ring 3, and the ring-shaped sealing element 12 made of plastic, which is connected to the first ring 6 in a sealing manner on the one hand and to the second ring 7 in a sealing manner on the other.
The first ring 6 and the second ring 7 of a respective sealing device 5′ do not overlap in the radial direction. The outer diameter of the first ring 6 is smaller than the inner diameter of the second ring 7.
The first and second rings 6, 7 of the respective sealing device 5′ are arranged here in axially spaced planes. This results in perfect and permanent sealing of the gap area.
In this way, covers 100′ for the torsional vibration damper 1 are formed, which each have the first ring 6, the second ring 7 and the sealing element 12.
The sealing element 12 is connected to the two first and second rings 6, 7 in a circumferentially sealing manner. In the prior art, this connection can be realized by a rubber-metal connection produced in particular during an elastomer crosslinking process.
In addition to the contact area 20, the graduation has a preferably circumferential groove 13, into which a material bead 14 of the sealing element 12 can be inserted at the edge. The sealing element 12 is clamped or held in a clamping manner in the groove 13 of the flywheel ring 3 via the material bead. The graduation has a screw channel 18, 18′ for accommodating a screw thread of a screw 15, 15′.
The outer ring 7 covers the contact area 20 and the groove 13 and thus clamps the sealing element 12. For this purpose, the ring 7 has screw bushings 16, 16′ with or without threads. The screw head of the screw 15, 15′ can also lie in a recess (not shown) in the ring 7 so that the screw 15, 15′ is flush with the outside 19 of the flywheel ring 3 and/or the outer ring 7.
The groove 13 is preferably trapezoidal in cross-section, so that the material of the material bead 14 is better distributed in the groove by the contact pressure of the ring 7 during screwing.
It is understood that several screws 15, 15′ are arranged circumferentially distributed on the outer ring 7.
The same arrangement results for the connection of the sealing element 12 to the hub part 2 by screwing the inner ring 6 to the hub part 2 and thereby clamping a material bead within a groove, preferably a circumferential groove, in the hub part 2. The material bead can advantageously be of the same shape as the material bead 12.
In the first variant Opt. 1, the ring 7 is screwed to the flywheel ring 3 outside the material of the sealing element 12.
In the second variant Opt. 2, the ring 7 is screwed to the flywheel ring 3 through the material of the sealing element 12. The sealing element 12, preferably the material bead 14, has a screw passage 17 so that the material bead, in addition to clamping, also extends the material of the mechanical connector through the material of the sealing element 12.
Instead of screwing the sealing element 12 to the hub part 2 and/or the flywheel ring 3 using corresponding screws, other forms of mechanical connectors, preferably pin-shaped connectors, particularly preferably fitting bolts, bushes, preferably slotted bushes, rivets and/or clamps, can also be used to create a corresponding connection.
In
The material bead 14″ in
As an alternative to the connection by mechanical connectors, the connection is made by a material connection in the form of a welded connection. Welding can take place in a transition area between the outer ring 7 and the flywheel ring 3 by means of a surface weld seam 21′.
Alternatively or additionally, the welding between ring 7 and the flywheel ring 3 can be carried out by means of a through-welded weld seam 21. Both weld seams 21, 21′ are preferably arranged outside the groove 14′.
The alternative or mutually combinable welded joints Opt. 1 and Opt. 2 of
The embodiment variants shown in the preceding variants also have a passage 24, which is arranged adjacent to the respective groove 13-13″ and is designed as a gap between the respective ring 6 or 7 and the hub part 2 or the flywheel ring 3, in which an adjacent region of the material bead 14-14″ of the sealing element 12-12″ is arranged. The gap width of this passage is greater than the extension of the sealing element 12-12″ within the gap, so that the sealing element 12-12″ has play in the area of the gap and is consequently arranged therein without load. As a result, the mounting of the sealing element is not overdetermined and material stresses are avoided.
The complementary shape between the material bead 14″ and groove 13″ results in a positive fit when the two areas are connected, with both elements locking against each other in the opposite direction to the insertion direction A. This facilitates pre-assembly and positioning of the sealing element. Furthermore, the retention of the sealing element 12″ is improved in the event of radial tension or pressure. In this case, the sealing element 12″ can be attached to the flywheel ring 3 and/or the hub part 2 exclusively by means of the positive fit, without the need for additional clamping, in order to ensure particularly quick and easy assembly. This means that both the outer ring 7 and the inner ring 6 can be advantageously omitted in this variant of
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2023 113 991.6 | May 2023 | DE | national |
