DE102020212889A1 - Wet-running multi-plate clutch and motor vehicle transmission - Google Patents

Abstract

Wet-running multi-plate clutch (AK, AK1, AK2, B) for a motor vehicle transmission (G), a piston (K) being provided on a first side of the multi-plate clutch (AK, AK1, AK2, B), by means of which a force acting on the disks (IL, AL) can be applied to close the disk clutch (AK, AK1, AK2, B), the disk clutch (AK, AK1, AK2, B) having a pressure plate (DT) on one of the first sides is supported on the opposite second side on a support element (GG), with a spring (SF) being arranged between the pressure plate (DT) and the support element (GG), the spring force of which acts against the closing direction of the multi-plate clutch (AK, AK1, AK2, B). , wherein the pressure plate (DT) is supported on a first surface (F1) of the support element (GG), and the spring (SF) on a second surface (F2) of the support element, the first and second surfaces (F1, F2) being axial are spaced apart, and transmission (G) for a motor vehicle drive train such a multi-plate clutch (AK, AK1, AK2, B).

Description

The present invention relates to a wet multi-plate clutch for a motor vehicle transmission and a transmission for a motor vehicle drive train with such a multi-plate clutch.

the EP 0 822 350 A2 describes a wet multi-plate clutch. In this case, friction elements are alternately connected to an outer element and to an inner element. The friction elements are axially displaceable and can be brought into frictional contact with one another by the application of axial force. According to the 6 and 7 illustrated embodiment EP 0 822 350 A2 the multi-plate clutch is supplied with lubricating oil from radially outside through a channel. When the multi-disc clutch is open, the lubricating oil can flow out through a gap between the last outer disk and a support disc. A corrugated spring is arranged in the gap and keeps the gap open when the multi-plate clutch is in the open state. When the multi-plate clutch is closed, the corrugated spring is compressed and thus closes the gap between the last outer plate and the support disc. A similar construction is in the DE 10 2010 002 934 A1 described.

However, such a solution impairs the ability to control or regulate the clutch. Because corrugated springs have bumps due to their construction. In addition, corrugated springs have a weld seam at at least one point, which leads to an additional unevenness of the corrugated spring. If the corrugated spring is pressed together when the clutch is closed, the unevenness can lead to the plates being supported at an angle. Such a crooked support can lead to jerking in the power transmission. This is undesirable.

It is therefore the object of the invention to provide a multi-disk clutch which is characterized by good controllability or regulation and yet only causes low drag losses in the open state.

The object is achieved by the features of patent claim 1. Advantageous refinements result from the dependent patent claims, the description and the figures.

To solve the problem, a wet-running multi-plate clutch for a motor vehicle transmission is proposed. The multi-plate clutch has an inner plate carrier and an outer plate carrier. Inner discs are connected to the inner disc carrier via a tooth system. External disks are connected to the external disk carrier via teeth. Inner discs and outer discs are arranged alternately.

The wet multi-plate clutch can be used both as a brake and as a clutch. When used as a brake, one of the two disc carriers is always non-rotatable. When used as a clutch, both disk carriers are rotatably mounted.

A piston is provided on a first side of the disk clutch, by means of which a force acting in the axial direction can be applied to the disks. As a result, the inner disks and the outer disks come into frictional contact with one another, so that torque is transmitted between the inner disk carrier and the outer disk carrier. The piston can be actuated in various ways, for example hydraulically or electromechanically. The multi-plate clutch is supported via a pressure plate on a support element which is located on a second side of the multi-plate clutch opposite the first side.

A spring is arranged between the pressure plate and the support element, the spring force of which acts against the closing direction of the multi-plate clutch. The spring is in the power flow between the piston and the support element.

According to the invention, the pressure plate is supported on a first surface of the support element and the spring is supported on a second surface of the support element. The first and second surfaces are axially spaced from each other. By using axially separate support surfaces, the pressure plate and spring can be arranged parallel to one another in the power flow between the piston and the support element. As a result, a flat support surface of the pressure plate can be ensured, so that the torque transmission of the multi-plate clutch can be controlled or regulated with a high degree of precision. If the multi-plate clutch is open, the spring continues to provide a gap for oil to drain out of the multi-plate clutch. As a result, the drag losses of the multi-plate clutch can be reduced in the open state.

Preferably, the first surface is closer to the fins than the second surface. Such a construction enables direct support without intermediate elements.

The spring is preferably designed in such a way that the force of the spring forms an axial gap between the pressure plate and the support element when the multi-plate clutch is in the open state. However, if the multi-plate clutch is closed for torque transmission, then this axial gap closed. Closing does not take place by flattening the spring, but rather by the pressure plate resting against the first surface of the support element.

The pressure plate is preferably arranged in such a way that oil can flow radially outwards around the pressure plate in the direction of the axial gap between the pressure plate and the first surface on the support element. This allows for a simple oil flow path when the multi-plate clutch is in the open state.

Preferably, the first surface of the support member is disposed radially inward of the second surface of the support member. In other words, the spring is located radially outside that surface on which the pressure plate is supported on the support element. Such a solution is easy to manufacture and assemble.

Preferably, the first and second surfaces are annular. Ring-shaped surfaces can easily be manufactured with the required flatness by machining.

The multi-plate clutch is preferably designed as a brake with a non-rotatable outer plate carrier, since in this way a low-resistance fluid path is formed for removing cooling oil from the non-rotating outer plate carrier. The drag torque can thus be reduced particularly effectively. When using the multi-plate clutch as a brake, the outer plate carrier can be firmly connected to the support element.

The pressure plate is preferably formed by an independent component, ie not by one of the end disks or one of the outer disks. As a result, a particularly uniform support of the disk pack can be achieved, so that misalignments are avoided.

At least some of the teeth of the toothing between the outer disks and the outer disk carrier preferably have a recess in the area of the tooth tip. A fluid path to the pressure plate and subsequently in the direction of the axial gap between the pressure plate and the support element is formed in a simple manner by the depressions.

Preferably, one spring element each is arranged in an axial gap between two adjacent outer disks, which spring element is designed, for example, as an annular corrugated spring. The spring elements push the outer disks apart in the axial direction, so that sticking between the outer disks and the inner disks when the multi-plate clutch is open is avoided. The spring force of the spring elements is chosen so that it corresponds at least approximately to the spring force of the spring between the pressure plate and the support element. As a result, a defined, floating state of the combination of outer disks and inner disks between the piston and the support element is achieved in a simple manner. As a result, a defined gap width between the pressure plate and the support element can be achieved when the multi-plate clutch is in the open state.

The multi-plate clutch is preferably a component of a transmission for a motor vehicle, for example an automatic transmission or an automated transmission. The drag torque of the transmission can be reduced by using the multi-plate clutch in the transmission. The use of the multi-plate clutch as a brake with a non-rotatable outer plate carrier is particularly preferred. The outer disk carrier and/or the support element can be formed by the housing of the transmission.

A rotatable shaft of the transmission is preferably arranged in the axial immediate vicinity of the axial gap between the pressure plate and the support element of the multi-plate clutch. By rotating the shaft, using the Venturi effect, a suction effect can be achieved for fluid emerging from the axial gap. Such a solution is particularly advantageous for a disk clutch designed as a brake, since the cooling fluid can be sucked out of the stationary disk carrier by the suction effect.

The multiple-disc clutch of the transmission preferably acts as a starting element of the motor vehicle drive train. When starting, the starting element enables the torque to be transmitted between the output side, which is initially stationary, and the rotating input side. A particularly precise control or regulation capability is required for such an application, so that the proposed multi-plate clutch is particularly suitable for this.

• 1a bis 1c schematisch je einen Antriebsstrang für ein Kraftfahrzeug;
• 2 bis 4 je eine Detail-Schnittansicht eines Getriebes; sowie
• 5 eine Frontansicht einer Außenlamelle.

Exemplary embodiments of the invention are described in detail with reference to the figures. Show it:

• 1a until 1c each schematically a drive train for a motor vehicle;
• 2 until 4 each a detailed sectional view of a transmission; such as
• 5 a front view of an outer blade.

1a shows schematically a drive train for a motor vehicle according to a first embodiment. The drive train has a burn voltage motor VM, which is connected via a gear G and a differential gear AG with drive wheels DW of the motor vehicle. The transmission G has a wheel set RS, which is set up to convert the torque and speed of the internal combustion engine VM into values suitable for driving the motor vehicle. For this purpose, the wheel set RS can have planetary gear sets and/or spur gear stages, which interact with various shifting elements for gear formation of the transmission G. The transmission G is assigned a starting element AK in the form of a friction clutch, which connects an output shaft of the internal combustion engine VM to an input shaft of the wheel set RS. When the motor vehicle starts, the starting element AK is operated in a slipping state in order to provide torque transmission between the rotating internal combustion engine shaft and the drive wheels DW, which are initially stationary, during the starting process. The wheelset RS and the starting clutch AK are surrounded by a housing GG of the transmission G.

1b shows schematically a drive train for a motor vehicle according to a second embodiment, which essentially corresponds to that in 1a corresponds to the version shown. The transmission G is now designed as a double clutch transmission, which has two parallel-connected starting elements AK1, AK2 designed as friction clutches. Each of the starting elements AK1, AK2 is assigned to a sub-transmission of the wheel set RS that is not shown in detail.

1c shows schematically a drive train for a motor vehicle according to a third embodiment, which essentially corresponds to that in 1a corresponds to the version shown. The transmission G of the powertrain according to the third embodiment does not have a separate starting clutch; instead, a shifting element of the wheelset RS acts as a starting element. This switching element is denoted by the reference symbol B and acts as a brake for a ring gear relative to the housing GG.

In order to ensure that the motor vehicle starts off smoothly and without jerks, the torque transmission of the starting elements AK, AK1, AK2, B must be easy to control or regulate. Wet-running multi-plate clutches are well suited for such an application. However, wet multi-plate clutches of this type exhibit drag losses in the open state, which reduce the mechanical efficiency of the drive train. In order to reduce the drag losses, it is advantageous if oil can easily flow out of the multi-plate clutch when the multi-plate clutch is open. However, if the multi-plate clutch is operated in a state of slippage, cooling oil should flow through the multi-plate clutch in order to prevent the multi-plate clutch from overheating. A simple flow of cooling oil from the multi-plate clutch can negatively affect the cooling effect.

2 shows a detailed sectional view of the transmission G, here as an example according to the 1c illustrated powertrain. In 2 the structure and the actuation of the multi-plate clutch B acting as a brake are shown in more detail. The multi-disk clutch B has an inner disk carrier ILT, which is formed on the radial outside of a ring gear HO. A number of inner disks IL are connected to the inner disk carrier ILT via a toothing ILZ, so that a torque can be transmitted between the inner disk IL and the inner disk carrier ILT. The inner disks IL can be displaced axially relative to the inner disk carrier ILT. The multi-plate clutch B also has an outer plate carrier ALT, which in the given exemplary embodiment is formed on an inner surface of the housing GG. A number of outer disks AL are connected to the outer disk carrier ALT via a toothing ALZ, so that a torque can be transmitted between the outer disk AL and the outer disk carrier ALT. The outer disks AL can be moved axially relative to the outer disk carrier ALT. Outer discs AL and inner discs IL are arranged alternately.

A spring element SF2 is arranged between adjacent outer disks AL. The spring elements SF2 are designed as ring-shaped corrugated springs. The spring elements SF2 push the outer disks AL apart in the axial direction, so that sticking between the outer disks AL and the inner disks IL when the multi-disk clutch B is open is avoided.

A piston K is arranged on a first side of the multi-plate clutch B. The piston K is loaded in the opening direction of the multi-plate clutch B by means of a return spring RF. A pressure chamber is provided between the piston K and a housing shield GS connected to the housing GG. If hydraulic pressure is applied to the pressure chamber, the piston K is actuated in the closing direction against the force of the return spring RF.

On a second side opposite the first side, the multi-plate clutch B is supported on a support element via a pressure plate DT. In the given embodiment, the support element is formed by the housing GG. The DT pressure plate ensures particularly even support, so that the disc pack is prevented from being skewed. Between the pressure plate DT and the housing GG is a Arranged spring SF, which is designed for example as a corrugated spring.

3 shows a further sectional view of the transmission G according to FIG 1c illustrated drive train, in which the support of the pressure plate DT on the housing GG is shown in more detail. It can be clearly seen that the pressure plate DT is supported on a first annular surface F1 of the housing GG, and that the spring SF is supported on a second annular surface F2 of the housing GG. The first surface F1 is axially spaced from the second surface F2, the first surface F1 being arranged axially closer to the lamellae AL, IL than the second surface F2. The first surface F1 is arranged radially inward of the second surface F2.

In the representation according to 3 the multi-plate clutch B is in the open state. The pressure plate DT is pushed away from the surface F1 on the housing GG by the force of the spring SF, so that an axial gap is formed between the pressure plate DT and the surface F1. Oil can flow out of the area of multi-plate clutch B through this gap. The oil flows radially around the outside of the pressure plate DT. Another outflow path for oil from the multi-plate clutch B is in the direction of the return spring RF. The oil flow is in 3 visualized by arrows.

A shaft T, which is connected to a planet carrier PT, is arranged axially in the immediate vicinity of the gap between the surface F1 and the pressure plate DT. The rotation of the shaft T creates a suction effect, which improves the draining of oil from the gap between the surface F1 and the pressure plate DT.

4 shows a further sectional view of the transmission G according to FIG 1c illustrated drive train, in which the support of the pressure plate DT on the housing GG is shown in more detail. In the representation according to 4 the multi-plate clutch B is in the closed, ie torque-transmitting state, in which the multi-plate clutch B is actuated in the closing direction due to pressure being applied to the piston K. The pressure plate DT comes into contact with the surface F1 against the force of the spring SF, so that the gap between the pressure plate DT and the surface F1 is closed. Cooling oil is supplied to the multi-plate clutch B from the first side. By closing the gap between the pressure plate DT and the surface F1, the oil must now flow through the lamellae IL, AL, so that the lamellae AL, IL are cooled. The oil flow is in 4 visualized by arrows.

5 shows a front view of one of the outer disks AL of the transmission G according to FIG 1c illustrated powertrain. The toothing ALZ on the disc side between the outer discs AL and the outer disc carrier ALT can be clearly seen there. The teeth have a depression ZKT in the area of the tooth head ZK. When the multi-plate clutch B is open, oil can flow through these depressions ZKT with reduced resistance in the direction of the pressure plate DT and around the pressure plate DT out of the multi-plate clutch B into the gap between the pressure plate DT and surface F1. If the multi-plate clutch B is closed or a torque is transmitted via the multi-plate clutch B, the oil can flow through the depressions ZKT with reduced resistance to the lamellae AL, IL, or through the lamellae AL, IL.

Reference List

VM

combustion engine

G

transmission

AK

starting element

AK1

starting element

AK2

starting element

RS

wheelset

Inc

differential gear

DW

drive wheel

GG

Housing; support element

B

multi-plate clutch; starting element

SF

Feather

SF2

spring element

DT

pressure plate

F1

First face

F2

second face

GS

housing shield

K

Pistons

RF

return spring

OLD

outer disc carrier

AL

outer slats

CC

tooth head

ZKT

deepening

ALZ

gearing

ILT

inner disc carrier

IL

inner slats

ILZ

gearing

T

Wave

HO

ring gear

pt

planet carrier

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 0822350 A2 [0002]
• DE 102010002934 A1 [0002]

Claims (15)

Wet-running multi-plate clutch (AK, AK1, AK2, B) for a motor vehicle transmission (G), the multi-plate clutch (AK, AK1, AK2, B) having an inner plate carrier (ILT, HO) with inner plates ( IL) and an outer disc carrier (ALT, GG) with outer discs (AL, ALE) connected to it via a tooth system (ALZ), the inner discs (IL) and the outer discs (AL) being arranged alternately, - on a first side of the Multi-plate clutch (AK, AK1, AK2, B) a piston (K) is provided, by means of which a force acting in the axial direction can be applied to the inner and outer plates (IL, AL) in order to move the multi-plate clutch (AK, AK1, AK2, B ) to close, - wherein the multi-plate clutch (AK, AK1, AK2, B) is supported via a pressure plate (DT) on a second side opposite the first side on a support element (GG), - wherein between the pressure plate (DT) and the Supporting element (GG) a spring (SF) is arranged, the spring force acts against the closing direction of the multi-plate clutch (AK, AK1, AK2, B), characterized in that the pressure plate (DT) on a first surface (F1) of the support element (GG) and the spring (SF) on a second surface (F2 ) of the support member are supported with the first and second surfaces (F1, F2) being axially spaced from each other. Wet multi-plate clutch (AK, AK1, AK2, B) according to claim 1 , characterized in that the first surface (F1) is arranged axially closer to the lamellae (AL, IL) than the second surface (F2). Wet multi-plate clutch (AK, AK1, AK2, B) according to claim 1 or claim 2 , characterized in that the spring (SF) is designed in such a way that - the force of the spring (SF) forms an axial gap between the pressure plate (DT) and the support element (GG) when the multi-plate clutch (AK, AK1 , AK2, B) is in an open state, and that - the axial gap is closed when the multi-plate clutch (AK, AK1, AK2, B) is in a torque-transmitting state due to actuation by the piston (K). Wet multi-plate clutch (AK, AK1, AK2, B) according to claim 3 , characterized in that the pressure plate (DT) is arranged such that oil can flow radially outwards around the pressure plate (DT) in the direction of the axial gap. Wet-running multi-plate clutch (AK, AK1, AK2, B) according to one of Claims 1 until 4 , characterized in that the first surface (F1) of the support element (GG) is arranged radially inside the second surface (F2) of the support element (F2). Wet-running multi-plate clutch (AK, AK1, AK2, B) according to one of Claims 1 until 5 , characterized in that the first surface (F1) and the second surface (F2) are annular. Wet-running multi-plate clutch (AK, AK1, AK2, B) according to one of Claims 1 until 6 , characterized in that the disk clutch (AK, AK1, AK2, B) is designed as a brake with a non-rotatable outer disk carrier (ALT, GG). Wet multi-plate clutch (AK, AK1, AK2, B) according to claim 7 , characterized in that the outer disc carrier (ALT, GG) is firmly connected to the support element (GG). Wet multi-plate clutch (AK, AK1, AK2, B) according to Claims 1 until 8th , characterized in that the pressure plate (DT) is an independent component which is not formed by one of the outer disks (AL) or one of the inner disks (IL). Wet-running multi-plate clutch (AK, AK1, AK2, B) according to one of Claims 1 until 9 , characterized in that at least some teeth of the toothing (ALZ) between the outer disks (AL) and the outer disk carrier (ALT, GG) in the area of the tooth tip (ZK) have a depression (ZKT), so that oil in the axial direction through the depression ( ZKT) can flow to the spring (SF). Wet-running multi-plate clutch (AK, AK1, AK2, B) according to one of Claims 1 until 10 , characterized in that a spring element (SF2) is arranged in an axial gap between adjacent outer disks (AL), the spring force of the spring elements (SF2) at least approximately corresponding to the spring force of the spring (SF). Transmission (G) for a motor vehicle drive train, characterized by a wet multi-plate clutch (AK, AK1, AK2, B) according to one of Claims 1 until 11 . gear (G) after claim 12 , characterized in that the supporting element and/or the outer disk carrier (ALT) is formed by a housing (GG) of the transmission (G). gear (G) after claim 12 or Claim 13 , characterized in that in A rotatable shaft (T) of the gear (G) is arranged axially in close proximity to the first surface (F1) of the support element (GG), so that the rotation of the shaft (T) generates a suction effect of cooling fluid exiting at the surface (F1). . Gear (G) according to one of Claims 12 until 14 , characterized in that the multi-plate clutch (AK, AK1, AK2, B) acts as a starting element of the motor vehicle drive train.

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