DE102024114876A1 - Multi-plate clutch and friction plate for this - Google Patents

Abstract

The invention relates to a multi-plate clutch (1) and a friction plate (7) for this clutch for wet operation by means of a fluid with a plate pack (6) arranged about a rotational axis (d) of the multi-plate clutch (1) and axially loadable to form a frictional connection, consisting of alternately axially layered friction plates (7) and counter plates (8), wherein the friction plates (7) are rotationally fixed to a first and the counter plates (8) are connected to a second plate carrier (2, 3) and each plate carrier (2, 3) is assigned to an input part and the other plate carrier (2, 3) to an output part of the multi-plate clutch (1), wherein the friction plates (7) include a carrier disk (11) with friction segments (12) arranged on both sides. In order to manufacture such a lamellar coupling (1) with low drag torque and in a cost-effective manner, four to eight, preferably six, friction segments (12) are provided distributed around the circumference with first impressions (13) formed axially at their circumferential ends and the first impressions (13) form an enlarged passage space (19) for the fluid by means of radial gaps (15) which space the friction segments (12) apart from each other in the circumferential direction.

Description

The invention relates to a multi-plate clutch and a friction plate for this for wet operation with a plate pack arranged around a rotational axis of the multi-plate clutch and axially loadable to form a frictional connection, consisting of alternately axially layered friction plates and counter plates, wherein the friction plates are rotationally fixed to a first and the counter plates to a second plate carrier, and a first plate carrier is assigned to an input part and the other plate carrier to an output part of the multi-plate clutch, wherein the friction plates include a carrier disc with friction segments arranged on both sides.

The printed materials EP 1 876 369 A2 , EP 2 551 543 A1 , WO 2022/111750 A1 Figure 1 shows friction plates for wet-operated multi-plate clutches, such as those operated with oil, which are known per se and feature friction segments arranged on both sides and distributed around the circumference. A plurality of more than sixteen friction segments are mounted on a carrier disc, maintaining a radial gap. The number of friction segments essentially corresponds to the number of teeth of a toothed section on the carrier disc for rotationally fixed mounting of the friction plate to a plate carrier, or is only slightly less. Each of these friction segments is positioned and mounted on the carrier disc, forming a radial gap to the next friction segment along the circumference.

Within at least a portion of the friction segments, various indentations are provided to form fluid paths, particularly when the multi-plate clutch is closed and several friction plates are axially pre-tensioned, alternating with counter plates to form a plate pack. These fluid paths partially correspond to fluid openings in the associated plate carrier of the multi-plate clutch and/or in the carrier disc to achieve improved fluid flow across the plate pack.

The multi-plate clutches containing these friction plates are used, for example, in hybrid or purely electric powertrains as so-called separator clutches, which connect and disconnect two electric motors or a drive unit consisting of an internal combustion engine and an electric motor with another electric motor. For the quality of the powertrain control, it is essential that the multi-plate clutch exhibits a low load torque in the open state and that precise load torque behavior occurs during switching operations, especially at high speeds.

The object of the invention is the further development of a multi-plate clutch and the friction plates for it. In particular, the object of the invention is to propose a multi-plate clutch and friction plates for it which are, on the one hand, cost-effective to manufacture and, on the other hand, can be operated with low drag torques.

The problem is solved by combining the features of the subject matter of claims 1 and 3. The dependent claims describe advantageous embodiments of the subject matter of claims 1 and 3.

The proposed multi-plate clutch is designed for wet operation, for example, cooled with a fluid such as oil, ATF, or the like. Preferably, the proposed multi-plate clutch is used as a disconnect clutch, similar to a separator clutch, in a hybrid or purely electric powertrain of a motor vehicle, connecting and disconnecting two electric motors, particularly at high speeds. The multi-plate clutch is arranged around a rotational axis and includes an input-side and an output-side plate carrier, each with an axial, for example, cup-shaped projection. Radially between these projections, a plate pack is arranged, consisting of axially alternating friction plates and counter plates. The counter plates and the friction plates are each rotationally fixed or interlocked, for example, by forming appropriate profiles such as toothed sections, within a plate carrier, thus forming the plate pack. Frictional engagement of the multi-plate clutch, and thus the transmission of torque, is achieved by axially acting upon the plate pack, thereby clamping the counter-plates and friction plates against each other.

Preferably, the counter-lamellae are formed from metal discs, such as metal rings with friction surfaces, while the friction lamellae comprise a carrier disc with friction segments arranged on both sides. The two axial projections of the lamella carrier are preferably arranged radially one above the other and have mutually facing profiles, such as molded-on teeth. Preferably, the friction lamellae are rotationally fixed in the radially inner projection and therefore have internal teeth, while the counter-lamellae suspended in the radially outer projection have external teeth. It is understood that, conversely, the friction lamellae can be suspended in the radially outer projection of the associated lamella carrier and have external teeth.

The trouble-free transmission of torque when the multi-plate clutch is closed, as well as a reduction of drag torque when the multi-plate clutch is opening or open, depends on a variety of parameters, in particular the design such as shape and material of the friction segments and temperature-dependent properties of the fluid.

To design the multi-plate clutch cost-effectively and with optimized drag torque, the friction plates are equipped with a combination of several features that, in total, improve the drag torque without compromising cost-effective manufacturing. For this purpose, a relatively small number of friction segments, namely four to eight, preferably six, are applied to each side of the carrier disc, which is preferably ring-shaped and made of sheet metal, for example, bonded to it. The friction segments are made of friction material, for example, paper.

For the purposes of the invention, "paper" is understood to mean fibrous material, for example containing at least some aramid fibers, with optionally added additives, for example to increase the coefficient of friction, elasticity, temperature resistance, and/or the like, which is, for example, suspended in a pulp and steam-pressed into semi-finished products such as sheets, rolls, or the like. The friction segments may be die-cut from the semi-finished product.

Reducing the number of friction segments simplifies both the positioning and application of the friction segments to the carrier disc, thereby reducing assembly effort and costs. Furthermore, the larger extension angle of the individual friction segments, for example from 45° to 90°, preferably 60°, allows for improved friction surface structures on the friction surface of the friction segments, specifically designed to reduce drag torques when the multi-plate clutch is opening or fully open. In addition, axially formed first indentations are preferably provided on both sides at the circumferential ends, with the friction segments spaced apart from each other circumferentially by radial gaps. These radial gaps facilitate the flow of fluid for cooling the multi-plate assembly. The inflow and outflow of fluid are supported by the first indentations, ensuring that, particularly when the multi-plate clutch is opening, the fluid flows away quickly and the resulting drag torques are minimized.

It has proven advantageous if at least the axial projection of the associated lamella carrier, which holds the friction lamellae in a rotationally fixed manner, has openings at least on a portion of the circumference of the radial gaps. The fluid is supplied and discharged through these openings.

The problem is also solved by a friction plate for the proposed multi-plate clutch, in which a carrier disc contains friction segments arranged on both sides. Four to eight, preferably six, friction segments are distributed around the circumference, each with axially formed first indentations at its circumferential ends, and the friction segments are spaced apart from each other circumferentially by radial gaps. This combination of features allows for cost-effective manufacturing and optimization of the drag torque in friction plates, since, on the one hand, a small number of components need to be processed, and on the other hand, the wide extension angle allows for indentations, particularly at the circumferential ends, that can extend over a wide angle in the circumferential direction. Compared to a single-piece, annular friction segment, this design allows for sufficiently dimensioned radial gaps between the individual friction segments. Furthermore, significant material savings are possible because a punching cutout within an annular friction segment is eliminated. Rather, the friction segments can be arranged almost seamlessly and with minimal material usage along a sheet, strip, or roll-shaped semi-finished product. The embossing can be incorporated, for example, during the paper's production as a semi-finished product using a hot-pressing process. This can be achieved, for instance, by using a suitably profiled press roller or press plate, and then, after the semi-finished product has cooled, the friction segments can be cut out, punched, or separated in a similar manner.

According to an advantageous embodiment of the proposed friction plate, at least one second indentation can be provided in the friction segments between the first circumferential indentations. Preferably, two second indentations are provided per friction segment, resulting in three axially raised friction areas. The radial transitions between the friction areas and the indentations can be formed precisely on the diameter through the axis of rotation, creating trapezoidal friction areas, or they can form an angle relative to the diameter, resulting in geometrically identical or different friction areas. When the multi-plate clutch closes, the friction areas first come into contact with the friction surfaces of the counter plates, with the indentations facilitating a fluid flow. to enable, in particular in the case of a slipping multi-plate clutch, the dissipation of frictional heat and to prevent uncontrolled adhesion of the friction segments to the counter plate, which increases the drag torque.

Depending on the design of the axial elasticity of the friction segments and/or the actuating force of the multi-plate clutch applied to the plate pack, the friction areas can be reversibly deformed axially when the multi-plate clutch is closed, so that the indentations also contribute at least a small amount to friction when the multi-plate clutch is completely closed, exhibiting only slight or no slippage, and thus increase the maximum torque that can be transmitted via the multi-plate clutch.

The surface area of the indentations, including the radial gap, can be greater than 40%, preferably greater than 50%, of the total area of the friction segments. The circumferential extent of the first indentation can be 1 to 5 times, preferably 1 to 2 times, the circumferential width of the radial gap. This means that, despite the reduced thickness of the first indentations compared to the radial gaps, the volume required to allow fluid flow is at least equal to or greater due to the circumferential proximity of two first indentations on two friction segments. For example, with a friction segment thickness of 0.5 mm to 0.7 mm, preferably 0.6 mm, the groove depth of the indentations is 0.2 mm to 0.3 mm, i.e., approximately half the thickness. It is understood that with other thicknesses of the friction segments, the groove depth can also be different, for example, half the thickness or less.

The friction lamella can be shortened radially outwards in the circumferential direction, for example, by having chamfers on the first indentations radially outwards. This creates a radially outward chamfer that, for example, forms an inlet or outlet funnel for the fluid. These chamfers, preferably arranged on both sides of a friction segment, are advantageous for saving on lining material such as paper for forming the friction segments, since the friction segments become narrower overall without losing significant friction surface area. A phase angle with respect to the diameter of the circumferential ends of the friction segment can, for example, be between 20° and 40°.

The carrier disc of the friction plate can be made of metal, plastic, in particular fiber-reinforced plastic, ceramic, composite material, and/or similar material. According to an advantageous embodiment of the friction plate, the carrier disc is made of spring steel and has a corrugated surface. Depending on the number of corrugations or vertices, predetermined portions of the friction segments, preferably the friction areas, engage with the counter plates first when the clutch is closing, and predetermined portions of the friction segments lift off first when the clutch is opening, so that the friction engagement and thus the drag torque can be defined more precisely. The axial amplitude of the corrugations can be, for example, in the range of the thickness of the indentations or less. The number of corrugations can be approximately equal to the number of friction segments around the circumference of the friction plate up to the number of indentations around the circumference of the friction plate.

• 1 den oberen Teil einer um eine Drehachse verdrehbar angeordneten Lamellenkupplung im Schnitt,
• 2 eine Ansicht einer Reiblamelle der Lamellenkupplung der 1,
• 3 eine 3D-Anicht der Reiblamelle der 2,
• 4 eine Detailansicht der Reiblamelle der 2 und 3 im Bereich der ersten Anprägungen,
• 5 einen Schnitt durch das Detail der 4 und
• 6 einen Längsschnitt durch die Reiblamelle der 2 und 3.

The invention is described in the following: 1 to 6 The illustrated embodiment is explained in more detail below. These show:

• 1 the upper part of a multi-plate clutch arranged to rotate about an axis of rotation, in section,
• 2 a view of a friction plate of the multi-plate clutch of the 1 ,
• 3 a 3D image of the friction plate of the 2 ,
• 4 a detailed view of the friction plate of the 2 and 3 in the area of the first impressions,
• 5 a cross-section through the detail of 4 and
• 6 a longitudinal section through the friction plate of the 2 and 3 .

The 1 Figure 1 shows the upper part of the lamellar coupling 1, which is rotatable about the axis of rotation d, in section with the two lamellar carriers 2, 3, which receive the lamellar package 6 on the radially superimposed axial projections 4, 5.

The lamellar package 6 is formed from the friction lamellae 7, which are alternately layered in the axial direction and are suspended in the projection 4 in a rotationally fixed manner, and the counter lamellae 8, which are suspended in the projection 5 in a rotationally fixed manner.

To actuate the multi-plate clutch 1, the actuating lever 9, which is axially actuated by an actuating unit, axially pre-tensions the multi-plate pack 6 against the stop 10, so that a frictional connection is formed between the friction plates 7 and the counter plates 8.

The friction plates 7 have ring-shaped carrier discs 11, on which there are plates on both sides over the The friction segments 12 are arranged circumferentially, with the section along a radial gap separating the friction segments from each other in the circumferential direction being shown. The friction segments 12 each have indentations 13 at their circumferential ends facing the counter lamellae 8, which improve the free passage of fluid flowing through the lamella pack, wherein radially opposite openings 14, like passage openings, are provided in the projection 4 opposite the radial gaps and first indentations 13.

The 2 and 3 show one of the friction plates 7 arranged around the axis of rotation d of the 2 In both horizontal and 3D views. In the illustrated embodiment of the friction plate 7, six friction segments 12 with a circumferential angle slightly less than 60° are arranged on each side, distributed around the circumference. As shown, the friction segments 12 are arranged in phase on both sides of the carrier disc 11, meaning that the radial gaps 15 separating the friction segments 12 circumferentially are located at the same circumferences. In further embodiments, the friction segments 12 on one side of the carrier disc 11 can have a circumferential angle relative to the friction segments 12 on the other side.

The friction segments 12 are arranged outside the toothing 16 for the rotationally fixed mounting of the friction plate 7 on the plate carrier 2. The toothing 16 comprises a multiple of teeth 17 compared to the number of friction segments 12 – in this case, a factor of three.

The friction segments 12 have circumferential indentations 13 that enlarge the passage space 19 with width B relative to the radial gaps 15 for fluid. Circumferentially, between the first indentations 13, two circumferentially spaced second indentations 18 are arranged, resulting in three axially raised friction areas 20 per friction segment 12. The dividing lines 21 between the indentations 13 and 18 have an angle of attack α relative to the diameter D1, forming trapezoidal friction areas 20 with a radially inner, narrower base. The dividing lines 21 of the first indentations 13 narrow the passage space 19 radially outward.

The 4 Detail D of the friction plate 7 is shown. 2 and 3 The view shows the area of the radial groove 15 separating the two friction segments 12. The first indentations 13 and the radial groove 15 form the passage space 19 with width B, where the width a of each indentation 13 is at least one to two times the width b of the radial groove 15. The radial groove 15 has a width b of, for example, 2 mm. The radial groove 15 is arranged radially outside the tooth gap 22 of the toothing 16, so that the radial groove is located directly radially outside a passage opening of a tooth of the toothing of the lamellar carrier, which is complementary to this toothing 16 and receives the friction lamella 7. The friction segments 12, or rather the first indentations 13, have radially inner radii 23 and radially outer chamfers 24 that are enlarged accordingly. The chamfers 24 have a phase angle β between 20° and 40° relative to the diameter D of the friction plate 7 and thereby shorten the overall length of the friction segments 12, so that these can be manufactured in a material-saving manner by making the semi-finished product provided for them and their manufacturing tools narrower.

The 5 The friction plate 7 shows the 2 and 3 as a section of detail D of the 4 with the carrier disc 11 and the friction segments 12 arranged on both sides. The first indentations 13, spaced apart from each other in the circumferential direction by the width b of the radial gap 15, are recessed relative to the friction areas 20 by the groove depth t. For example, the groove depth t is approximately half the thickness d1 of the friction segment 12. In the illustrated embodiment, the thickness d1 is approximately 0.6 mm and the groove depth is a maximum of 0.3 mm.

The 6 Figure 1 shows the friction plate 7 arranged around the axis of rotation d from the preceding figures in longitudinal section with the friction segments 12 arranged on both sides. The carrier disk 11 has the corrugation 25 around its circumference, which is not shown to scale. The amplitude w of the corrugation 25, for example, moves at most in the region of the thickness d2 of the friction plate 7 and preferably at most in the groove depth t ( 5 ) of the imprints 13, 18. The number of individual waves of the corrugation 25 can range from the number of friction segments to the number of friction zones 20. The corrugation, for example, causes the friction segments 12 to lift quickly from the counter plates 8 when the multi-plate clutch 1 opens, thus reducing drag torques.

Reference symbol list

1

Multi-plate clutch

2

Lamella carrier

3

Lamella carrier

4

Approach

5

Approach

6

Louver package

7

friction plate

8

Counter lamella

9

Actuating lever

10

stop

11

carrier disc

12

Friction segment

13

embossing

14

opening

15

radial gap

16

Interlocking

17

Tooth

18

embossing

19

Passageway

20

Friction area

21

dividing line

22

gap between teeth

23

Rounding off

24

Bevel

25

ripples

a

Width

B

Width

b

Width

D

detail

D1

diameter

d

axis of rotation

d1

thickness

d2

thickness

t

Groove depth

w

amplitude

α

angle of attack

β

angle of attack

QUOTES INCLUDED IN THE DESCRIPTION

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

• EP 1 876 369 A2 [0002]
• EP 2 551 543 A1 [0002]
• WO 2022/111750 A1 [0002]

Claims (10)

A multi-plate clutch (1) for wet operation by means of a fluid, comprising a plate pack (6) arranged about a rotational axis (d) of the multi-plate clutch (1) and axially loadable to form a frictional connection, consisting of alternately axially layered friction plates (7) and counter plates (8), wherein the friction plates (7) are rotationally fixed to a first and the counter plates (8) to a second plate carrier (2, 3), and each plate carrier (2, 3) is assigned to an input part and the other plate carrier (2, 3) to an output part of the multi-plate clutch (1), wherein the friction plates (7) include a carrier disk (11) with friction segments (12) arranged on both sides, characterized in that four to eight, preferably six, friction segments (12) are provided distributed around the circumference with first indentations (13) formed axially at their circumferential ends, and the first indentations 13 are connected by means of the friction segments (12) radial gaps (15) spaced apart from each other in the circumferential direction form an enlarged passage space (19) for the fluid. multi-plate clutch (1) according to Claim 1 , characterized in that an axial projection (4) which receives the friction lamellae (7) in a rotationally fixed manner has openings (14) at least on at least one of the lamella carriers (2) on at least part of the circumferences of the radial gaps (15). Friction plate (7) for a multi-plate clutch (1) according to one of the Claims 1 or 2 , characterized in that a carrier disk (11) contains friction segments (12) arranged on both sides, wherein four to eight, preferably six, friction segments (12) are provided distributed around the circumference with first embossings (13) formed axially at their circumferential ends and the first embossings 13 together with radial gaps (15) spaced apart from each other in the circumferential direction form an enlarged passage space (19) for the fluid. friction plate (7) according to Claim 3 , characterized in that at least a second imprint (18) is provided in the friction segments (12) between the first imprints (13) in the circumferential direction. friction plate (7) according to Claim 4 , characterized in that a surface area fraction of the imprints (13, 18) is greater than 40%, preferably greater than 50% of the total surface area of the friction segments (12). Friction plate (7) according to one of the Claims 3 until 5 , characterized in that a width (a) of the first imprint corresponds to 1 to 5 times, preferably 1 to 2 times, the width (b) of the radial gap in the circumferential direction. Friction plate (7) according to one of the Claims 3 until 6 , characterized in that a groove depth (t) of the indentations (13, 18) is 0.2 mm to 0.3 mm. Friction plate (7) according to one of the Claims 3 until 7 , characterized in that the first impressions (13) have radially outward chamfers (24). friction plate (7) according to Claim 8 , characterized in that the chamfers (24) have a phase angle (β) between 20° and 40° to the diameter (D) of the circumferential ends of the friction segments (12). Friction plate (7) according to one of the Claims 3 until 9 , characterized in that the carrier disc (11) is made of spring steel and is corrugated over its circumference.