Patent Application
20230375057
The present disclosure relates to a friction part for a frictionally operating device. The friction part includes at least one annular-disc-like friction surface which is rotated about a rotational axis in a wet-running manner relative to a mating surface and is formed from a paper material. The present disclosure further relates to a wet-running multi-plate clutch or multiple-disc brake with at least one such friction part.
From the German patent application DE 10 2009 013 406 A1, a method for producing a friction lining in a cooling press is known, which has a conically shaped pressing tool. From the German patent application DE 10 2011 086 926 A1, a friction clutch with friction surfaces and friction linings is known, which are conical in relation to a rotational axis of the friction clutch. From the German patent application DE 10 2015 206 018 A1 a disc clutch with inner plates is known which have annular cross-sections which taper radially outwards in a contact region, wherein outer plates have annular cross-sections which taper radially inwards in the contact region.
The present disclosure provides a friction part for a frictionally operating device. The friction part has at least one annular-disc-like friction surface which is rotated about a rotational axis in a wet-running manner relative to a mating surface and is formed from a paper material. The friction surface has at least one meso-geometric or micro-geometric uneven portion in order to create, in the friction surface, at least one axially deep friction region and at least one axially high friction region which is more strongly preloaded than the axially deep friction region when the friction surface and the mating surface are axially pressed together. The term axial refers to the rotational axis of the friction part. Axial means in the direction of or parallel to the rotational axis of the frictional part. The terms radial and tangential used below also refer to the rotational axis of the friction part. Radial means transverse to the rotational axis of the friction part.
The friction part includes at least one friction lining made of a paper material. This friction lining is also referred to as paper lining or friction paper. The paper lining or friction lining is, for example, firmly bonded to a corresponding carrier element. Paper linings are made in a similar way to paper. In the manufacture of paper linings, for example, a paper web is produced from which the paper lining is cut. The paper lining that has been cut out can then be bonded to the carrier element. Pieces of paper lining or pieces of friction paper that are cut out or punched out are also referred to as pads. These pieces of friction paper or pads are then bonded to the carrier element spaced apart from one another. The spacings between the pieces of paper lining or pieces of friction paper allow grooves to be produced in the friction surface, which allow a cooling and/or lubricating medium, such as oil, to pass through.
The carrier element is designed, for example, as a carrier plate and can be corrugated or uncorrugated. Conventional wet-running friction papers, which are also referred to as wet-running papers, normally have a macro-geometric and meso-geometric flat surface over the entire circumference of a friction plate. In the case of the disclosed friction part, the surface of the wet-running friction paper is deliberately not even, i.e. it is uneven. In order to realize the at least one axially deep region and the at least one axially high region, the paper material for representing the friction surface can be designed differently. The surface of the paper material can, for example, be conical, e.g., with a single cone or double-conical, or spherical.
In this case, a spacing between the axially deep region and the axially high region of the friction surface is rather small; e.g., the spacing is in the micron range. The spacing, which is realized, for example, by a targeted conicity or by a spherical shape of the paper material, means that when a contact pressure is applied, the high friction region(s) are more strongly preloaded than the deep friction region(s), whereby the deep friction region(s) lead to a forced separation from the mating surface when the contact pressure is removed. This makes it easier for air to enter the friction gap. In addition, an oil film thickness in the friction contact region can be increased by a suitable design of the friction surface between the axially deep friction region and the axially high friction region, which in turn leads to a higher level of friction. A drag torque during operation of the frictionally engaged device can be reduced by the claimed friction part, e.g., without the use of corrugated springs. In addition, the static friction level can be increased.
In an example embodiment of the friction part, the friction surface is conical. According to this exemplary embodiment, the entire friction surface formed with the paper material is conical. In this case, the friction surface can be designed conically inwards or conically outwards. This means that the axially deep friction region is arranged either radially on the inside or radially on the outside. Similarly, the radially high friction region is arranged radially on the outside or inside.
In a further exemplary embodiment of the friction part, the friction surface is double-conical. In a double-conical design, the friction surface has one axially deep friction region and two axially high friction regions or one axially high friction region and two axially deep friction regions. The friction surface of the double-conical design may be represented with pieces of friction paper, as explained below.
In another exemplary embodiment of the friction part, the friction surface is formed from pieces of friction paper, of which at least one piece of friction paper has at least one meso-geometric or micro-geometric uneven portion in order to create with the piece of friction paper at least one axially deep friction region and at least one axially high friction region which is more strongly preloaded than the axially deep friction region when the friction surface and the mating surface are axially pressed together. The use of the pieces of friction paper or pads enables a desired groove pattern to be produced in the friction surface in a simple manner.
In a further exemplary embodiment of the friction part, the piece of friction paper is conical in relation to a radial. A conical friction surface, which is interrupted by grooves, can thus be realized in a simple manner over the circumference of the friction part.
In a further exemplary embodiment of the friction part, the piece of friction paper is conical in relation to a tangential. Tangentially conical means, for example, that an axial dimension of the piece of friction paper between the axially deep friction region and the axially high friction region increases steadily in the tangential direction. In this way, a higher preloading can be realized in a simple manner in the tangential direction on the piece of friction paper. A cone in the direction of rotation can also reduce the risk of undesired floating during operation of the friction part. Depending on the design of the cone, a higher oil film thickness and thus a higher coefficient of friction can also be achieved.
In a further exemplary embodiment of the friction part, the piece of friction paper is double-conical. In this way, a higher preloading on the piece of friction paper can be realized in the tangential direction. When the contact pressure is removed, air can penetrate more easily into the resulting gap of the double-conical design, which simplifies separation from the mating surface.
In a further exemplary embodiment of the friction part, the piece of friction paper is spherical. The piece of friction paper can be spherical in the radial and/or in the tangential direction. By means of a spherical design at the level of the pieces of friction paper, which are also referred to as individual pads, a uniformity of the contact pressure can be achieved, which overall homogenizes the energy input in relation to the friction surface. As a result, local overloads can be avoided or reduced. This effectively increases the performance of the friction system.
In a further exemplary embodiment of the friction part, an axial distance between the axially deep friction region and the axially high friction region is between five and one hundred microns. In view of the advantages presented, this region has proven to be particularly effective.
The present disclosure further relates to a wet-running multi-plate clutch or multiple-disc brake with at least one previously described friction part. The friction part may be a friction plate, which is equipped on both sides with the friction paper or piece(s) of friction paper described above.
Further advantages, features and details of the disclosure will be apparent from the following description, in which various exemplary embodiments are described in detail with reference to the drawing. In the figures:
In
During operation of the frictionally operating device 20, the friction part 1 can be rotated about a rotational axis 3. The friction surface 2 essentially has the shape of a circular ring disc with an inner diameter 4 and an outer diameter 5. The friction surface 2 is shown with a friction lining, which may be designed as friction paper.
The friction paper can represent the entire friction surface 2.
The friction paper or the pieces of friction paper 10 are glued onto a carrier element 8. Contrary to what is shown, the carrier element 8 is equipped with toothing radially on the inside or radially on the outside. The toothing is used to create a non-rotatable connection with a plate carrier (also not shown) of the frictionally operating device 20.
The frictionally operating device 20 with the friction part 1 is operated wet. This means that a cooling and/or lubricating medium, such as oil, is conducted past the friction surface 2. Normally, the friction surface 2 is flat. The friction surface 2 of the disclosed friction part 1 is designed to be uneven or not even.
An arrow 28; 38; 49 indicates a contact pressure which is applied, for example, to the friction part 1 with the friction surface 23, 24; 33, 34; 43, 44 via a steel plate indicated only by a rectangle 29; 39; 50. When applying the contact pressure 28; 38; 49 the steel plate is pressed against the friction surface 23; 33; 43 with a mating surface 40.
By means of symbolically indicated springs in the rectangle 29; 39; 50,
In
It should be noted that
The conically designed friction paper or piece of friction paper 21 is easy to produce; for example, by a conical design of a pressing tool or gluing tool.
In
In
The embodiment of the piece of friction paper 31 with the friction surface 33 shown in
In
The double-conical design results in a higher preload on the piece of friction paper 41 in the tangential direction on both edges, i.e. radially on the outside, when the contact pressure 49 is applied. The edges of the piece of friction paper 41 may be spherical.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 126 942.0 | Oct 2020 | DE | national |
This application is the United States National Phase of PCT Appln. No. PCT/DE2021/100756 filed Sep. 14, 2021, which claims priority to German Application No. DE102020126942.0 filed Oct. 14, 2020, the entire disclosures of which are incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/DE2021/100756 | 9/14/2021 | WO |
