CN212272867U

CN212272867U - Multi-disc friction clutch

Info

Publication number: CN212272867U
Application number: CN201922205845.5U
Authority: CN
Inventors: R·J·L·范德沃尔德; A·A·M·范德曾; P·W·C·范德摩特勒
Original assignee: Punch Powertrain NV
Current assignee: Nanjing Bangqi Automatic Transmission Co ltd
Priority date: 2018-12-05
Filing date: 2019-12-05
Publication date: 2021-01-01
Anticipated expiration: 2029-12-05
Also published as: BE1026834A1; DE202019106775U1; BE1026834B1

Abstract

A multi-plate friction clutch having externally splined annular friction plates and internally splined annular friction plates arranged in a row of alternating externally splined and internally splined friction plates. The friction plate is provided with fluid passing holes in the axial direction. The apertures each communicate with at least one aperture in one of the adjacent friction plates to allow fluid to pass through the friction plates in an axial direction.

Description

Multi-disc friction clutch

Technical Field

The invention relates to a multi-plate friction clutch, comprising: a plurality of externally splined annular friction plates each having a splined engagement profile on its outer periphery; a plurality of internally splined annular friction plates each having a splined engagement profile on an inner periphery thereof; wherein the external spline friction plates and the internal spline friction plates are arranged in a row along and coaxially with the rotational axis.

Background

In a vehicle using an internal combustion engine, a clutch used as a starting (or clutch) clutch sometimes receives a severe thermal load and a large torque due to a large difference in rotation speed between the slip/entry/exit sides for a long time and/or a slip at the time of transfer. Typically, the factor that determines the size of such clutches is not the torque transfer capability, but the ability to operate without overheating. However, the increase in size of the clutch increases the rotating weight and increases the manufacturing cost of the vehicle. Therefore, efficient cooling of the clutch is of critical importance. In wet clutches, cooling oil supplied to the clutch may be used to absorb and carry heat away from the location where the heat is generated.

One known method of cooling wet clutches is centrifugal splash cooling, wherein oil is caused to rotate and splash radially outward against the friction plates due to centrifugal forces generated by the rotational motion. In such clutches, the cooling effect and the distribution of the cooling effect tend to vary, so that, at least in some cases, the cooling becomes insufficient or hot spots remain which are insufficient for cooling. In turn, this results in premature wear and failure of the clutch or at least less comfortable clutch actuation, which can be disconcerting to the user.

These problems are more pronounced in clutches where the externally splined friction plates do not rotate and therefore these plates do not contribute to the centrifugal movement of the cooling oil.

Disclosure of Invention

It is an object of the present invention to provide a multi-plate friction clutch in which the cooling fluid is more reliably and evenly distributed over the friction plates.

According to the invention, this object is achieved by providing a clutch according to the following. The clutch includes: a plurality of annular externally splined annular friction plates each having a splined engagement profile on its outer periphery; a plurality of annular internally splined annular friction plates each having a splined engagement profile on an inner periphery thereof; wherein the outer spline friction plates and the inner spline friction plates are arranged in a row along and coaxially with the axis of rotation, the fluid pump; and a fluid supply conduit having a first end and a second end, the first end connected to the pump and having at least one port at the second end opposite the first end, the at least one port opening to an adjacent one of the friction plates. The friction plates are provided with fluid passing holes in the axial direction, the holes each communicating with at least one hole in an adjacent one of the friction plates to allow fluid to pass through the friction plates in the axial direction.

Via the liquid supply conduit, a cooling liquid, such as oil, may flow in an axial direction through one or more ports at an end of the fluid supply conduit opposite the pump and through the fluid passage holes in the friction plate in the axial direction. The holes in the friction plate form one or more ducts through which the cooling fluid flows in the axial direction. Since the holes actively (actively) guide the fluid through the friction plate in the axial direction along one or more predetermined paths, in operation the cooling fluid is reliably pushed through the friction plate, thereby providing a well-defined cooling effect in the parts of the friction plate remote from the radially inner and outer edges. The controlled flow can be predicted by calculation in a similar manner to the hydraulic circuit.

Thus, the set of friction plates is uniformly and predictably cooled. Furthermore, at each friction interface, the cooling fluid may also spread between the friction plates, thereby also providing a more uniform lubrication effect. More efficient, predictable, and reliable cooling allows for smaller and lighter clutch sizes. Lighter clutches may also be achieved because splash cooling, which requires complex components and construction to direct oil to the clutch, may be eliminated or provided in a simpler form.

Specific details and embodiments of the invention are set forth in the dependent claims.

Further features, effects and details of the invention can be seen from the detailed description and the drawings.

Drawings

FIG. 1 is a schematic cross-sectional view of an example of a clutch according to the present invention;

FIG. 2 is a perspective view, in cross-section, of a portion of another example of a clutch according to the present invention; and

FIG. 3 is another perspective cutaway view of a portion of the clutch shown in FIG. 2.

Detailed Description

In fig. 1, an example of a multi-plate friction clutch 1 is shown. The clutch 1 has externally splined annular friction plates (plates) 2, 3, each having a splined engagement profile on its outer peripheral edge 4, 5, and an internally splined annular friction plate (plate) 6, each having a splined engagement profile on its inner peripheral edge 7. In this example, the clutch 1 has a drive end 8 in the form of a shaft 9, with a drive clutch member 10 mounted to the shaft 9. The clutch member 10 has internal splines 11 (not all indicated with reference numerals) which engage with splined engagement profiles on the outer peripheries 4, 5 of the externally splined annular friction plates 2, 3. The driven end 12 of the clutch 1 is formed by a further shaft 13, to which further shaft 13 a driven clutch member 14 is mounted. The driven clutch member 14 has external splines 15 (not all indicated by reference numerals) which engage with splined engagement profiles on the inner periphery 7 of the externally splined annular friction plate 6.

Note that many variations of this general configuration are contemplated, such as the drive end and the driven end may be driven, and the drive end with, for example, trunnions, gears may be provided separately in place of the shaft, and/or the driven end or drive end may be fixed relative to the clutch housing and also optionally relative to a structure that also carries an electric motor coupled to the clutch.

In this example, the driven, internally splined friction plates 6 are each comprised of a carrier plate 16 and a friction bushing 17 (only one set of plates and bushings are indicated by reference numerals). However, the friction bushing may also be part of a driving, externally splined friction plate for each friction interface.

The driving, externally splined friction plates 2 and the driven, internally splined friction plates 6 are arranged in a row of alternating driving friction plates and driven friction plates. The row of friction plates is arranged along a rotation axis 18 and the friction plates 2, 6 are in the form of discs coaxial with the rotation axis 18. It is known to provide bearings between the driving and driven shafts and the clutch members.

For operating the clutch, a clutch master actuator 19 is provided, and this clutch master actuator 19 is hydraulically coupled to an annular clutch slave actuator 20 via a clutch operating conduit 21 extending through the drive shaft 9 and the driving clutch member 10. The primary clutch actuator 19 may be, for example, a master cylinder or a combination of a pressure source and a control valve (see, for example, belgian patent application 2018/5278).

The clutch operation pipe 21 extends partially coaxially in a portion of the clutch cooling liquid pipe 22. A clutch cooling liquid conduit 22 extends from a cooling liquid pump 23, through the drive shaft 9 and the drive clutch member 10, to an end port 24 open to an adjacent one of the friction plates 2.

The friction plates 2, 6, except for one of the last externally splined friction plates 3, are provided with

fluid passing holes

25, 26 in the axial direction. The

holes

25, 26 each communicate with the other of the

holes

25, 26 in the adjacent friction plate 2, 6 to allow liquid to pass through the friction plate 2, 6 in the axial direction.

Via the liquid supply conduit 22, a cooling liquid, such as oil, may pass in the axial direction through a port 24 at the end of the liquid supply conduit 22 opposite the pump 23 and through

fluid passing holes

25, 26 in the friction plates 2, 6 in the axial direction. The

holes

25, 26 in the friction plates 2, 6 form a pattern of ducts along which the cooling fluid flows in the axial direction. Since the

holes

25, 26 actively (positively) guide the liquid through the friction plates 2, 6 in the axial direction along the pattern of the predetermined path, in operation the cooling liquid is reliably pushed through the friction plates 2, 6, thereby providing a well-defined cooling effect in the parts of the friction plates 2, 6 remote from the radially inner and outer edges of the friction plates 2, 3, 6. Thus, the set of friction plates 2, 3, 6 is cooled uniformly and predictably. Furthermore, at each friction interface, the cooling fluid may also spread between the contacting plates of the friction plates 2, 3, 6, thereby also providing a more uniform lubrication effect.

A port 24 of the liquid supply conduit 22 is provided in the clutch member 10 in splined engagement with the externally splined friction plate 2. Thus, the friction plate 2 immediately adjacent the port 24 is fixed relative to the port 24 and the surface of the clutch member 10 in contact with the friction plate 2, so that no friction occurs at the surface of the clutch member 10 in relation to which the port 24 is provided.

The friction plate 3 furthest from the end port 24 is not provided with a hole. The flow of cooling liquid is pressed against the plate 3 and the overpressure in the holes 25 and the annular spaces 27, 28 causes the cooling liquid to be pressed between the friction lining 17 and the friction plates 2, 3, whereby the friction plates 2, 3 and the friction lining 17 are effectively cooled.

The apertures 25 open into annular spaces 28 (not all indicated by reference numerals) extending about the axis of rotation 18, the annular spaces 28 each being arranged such that adjacent apertures 25 on axially opposite sides of the annular space 28 are in continuous fluid communication if the friction plates 2, 6 through which the apertures 25 extend are rotated relative to each other about the axis of rotation 18. Similarly, the ports 24 and holes 25 in adjacent friction plates 2 open into an annular space 27 extending around the axis of rotation 18. The annular space 27 is arranged such that the ports 24 and some adjacent holes 25 are in continuous fluid communication via the annular space 27. Thus, when the friction plates 2, 6 are rotated relative to each other, the cooling liquid can be continuously maintained to flow through the set of friction plates 2, 6 in the axial direction even if the holes 25 and ports 24 are intermittently completely axially misaligned.

The annular spaces are each left between radially spaced coaxial ones of said friction bushings, the thickness of which extends in the axial direction over a common range of positions.

In order to distribute the cooling liquid flow evenly, the holes 25 are distributed in the circumferential direction in each friction plate 2, 6 provided with holes 25. In order to distribute the flow of the cooling liquid particularly uniformly, the holes 25 are distributed uniformly in the circumferential direction.

If the externally splined friction plate is stationary, it is particularly advantageous to supply the cooling liquid through the holes in the friction plate, since in this case the centrifugal effect resulting in the cooling liquid being pushed in a radially outward direction is small.

In order to efficiently supply cooling liquid to the radially outward portions of the friction plates 2, 3, 6, it is preferred that for each friction plate 2 provided with holes 25, the distance of the hole 25 from the innermost edge of each friction plate 2 is greater than 25%, more preferably greater than 35%, of the distance between the innermost and outermost edges of the friction plate 2.

In fig. 2 and 3, parts of a second example of a clutch according to the invention are shown. In the clutch according to this example, the cooling liquid is also supplied to the

friction plates

52, 53, 56 via a part of the housing 60. The housing delimits an annular space 77 in the form of an annular groove, ensuring that the liquid is distributed evenly in the circumferential direction around the axis of rotation. The outwardly splined friction plate 52 and the inwardly splined friction plate 56 have axial holes 75 for allowing a cooling liquid, preferably a liquid, to pass axially as indicated by the arrows in fig. 3. The friction linings 77 are each divided in an outer part 77A and an inner part 77B, leaving between the outer part 77A and the inner part 77B a peripheral groove 78, which peripheral groove 78 constitutes an annular space around the axis of rotation, through which the cooling liquid can pass continuously even if the axial holes 75 in the adjacent friction plates 2, 6 are temporarily misaligned.

In addition, the

friction lining parts

77A, 77B have a pattern of

grooves

79A and 79B, respectively (not all indicated by reference numerals), which provides a flow path in one of the two frictionally engaged friction surfaces of adjacent (consecutive) friction plates. Through these flow paths, the cooling liquid may flow radially outward between the

linings

77A, 77B and the adjacent friction plates 2, 3 (not shown). Due to the combination of the holes and grooves, the liquid will be distributed to all the clutch plates (plates) with minimal liquid loss. Instead of grooves, different types of recesses may also provide flow paths. Furthermore, the same or different types of grooves or recesses may alternatively or additionally be provided in the external spline friction plate. The combination of the holes 75 and

grooves

79A, 79B allows the cooling liquid to be distributed to all the clutch plates with minimal liquid loss.

Although in the present example cooling is performed by causing liquid to flow through the holes, similar cooling effects may also be achieved if air, gas or both gas and liquid flow through the holes (the gas and/or liquid may each be a mixture), although it may be necessary to accommodate flow rates and distribution of ports and holes in circumferential and radial directions. The flow through these holes may be continuous, but in order to reduce energy consumption, it is also conceivable to drive the fluid flow through the holes only in response to the occurrence of certain conditions, such as temperature and/or conditions of use (e.g. friction between driven and driving friction plates and/or clutch slip, while transmitting torque exceeding a given threshold limit).

Several features have been described as part of the same or separate embodiments. It will be understood, however, that the scope of the present invention may include embodiments having all or some of these features in addition to the particular combinations of features embodied in the examples.

Claims

1. A multi-plate friction clutch, said clutch comprising:

a plurality of annular externally splined annular friction plates each having a splined engagement profile on its outer periphery;

a plurality of annular internally splined annular friction plates each having a splined engagement profile on an inner periphery thereof;

wherein the outer spline friction plates and the inner spline friction plates are arranged in a row along and coaxially with a rotational axis,

a fluid pump; and

a fluid supply conduit having a first end and a second end, the first end connected to the pump and having at least one port at the second end opposite the first end, the at least one port opening to an adjacent one of the friction plates;

wherein the friction plates are provided with fluid passing holes in the axial direction, each of the holes communicating with at least one of the holes in an adjacent one of the friction plates to allow fluid to pass through the friction plates in the axial direction.

2. The clutch of claim 1, wherein the at least one port of the fluid supply conduit is disposed in a clutch member in splined engagement with the externally splined friction plate.

3. The clutch of claim 1, wherein the holes open into annular spaces extending about the rotational axis, wherein the annular spaces are each arranged such that adjacent ones of the holes on axially opposite sides of the annular spaces are in continuous fluid communication via at least one of the annular spaces if the friction plates through which the holes extend are rotated relative to each other about the rotational axis.

4. Clutch according to claim 1, characterized in that the friction plates are each provided with a plurality of said holes, wherein the holes are distributed in the circumferential direction.

5. The clutch of claim 4, wherein the holes are evenly distributed along the circumferential direction.

6. The clutch of claim 1, further comprising friction plate bushings, each disposed between a pair of the externally splined friction plates and the internally splined friction plates.

7. The clutch of claim 3, further comprising friction plate bushings, each disposed between a pair of the externally splined friction plates and the internally splined friction plates, at least some of the annular spaces each remaining between radially spaced, coaxial ones of the friction plate bushings, a thickness of the friction plate bushings extending in an axial direction within a common range of positions.

8. A clutch according to claim 1 or 2, characterized in that the externally splined friction plate is fixed.

9. A clutch according to claim 1 or 2, characterized in that for at least one of the friction plates the distance of the holes from the innermost edge of the friction plate is more than 25% of the distance between the innermost and the outermost edge of the friction plate.

10. A clutch according to claim 1 or 2, characterized in that a pattern of recesses, such as grooves forming flow paths with a radial component, is provided in at least one of each pair of frictional engagement surfaces of each pair of adjacent friction plates.