WO2015180780A1

WO2015180780A1 - Balancing element of a clutch device

Info

Publication number: WO2015180780A1
Application number: PCT/EP2014/061175
Authority: WO
Inventors: Arnaud DOLE; François THIBAUT
Original assignee: Valeo Embrayages
Priority date: 2014-05-28
Filing date: 2014-05-28
Publication date: 2015-12-03

Abstract

The invention relates to a friction clutch device (1) containing: - a cover (2) capable of being rotated around an axis X, and - a plurality of balancing elements (12) fixed on the cover, the balancing elements being regularly distributed around the X axis and each being fixed on the cover by an attachment member (13), each balancing element (12) being produced by sintering and comprising: - a support base (18) resting against the cover and having a hole allowing the attachment member through; and - machinable protrusions (16, 17) protruding from said base.

Description

Balancing element of a clutch device

Technical field of the invention

The invention relates to the field of clutch devices for a motor vehicle.

It relates more particularly to balancing elements to compensate for unbalance of a clutch device.

State of the art

In the state of the art, in order to allow coupling between a driving shaft, such as a crankshaft of a heat engine, and a driven shaft, such as an input shaft of a gearbox, it is known clutch devices. A clutch device comprises a clutch cover attached to the flywheel, a friction disk comprising a hub intended to be secured in rotation to the driven shaft, a pressure plate integral in rotation with the clutch cover and axially movable relative thereto and an annular diaphragm mounted hinged to the clutch cover. A clutch abutment moves the diaphragm to axially bias the pressure plate between an engaged position in which the friction disc is clamped between the pressure plate and a region of the reaction-roll motor flywheel and a disengaged position in which friction disc is released. Thus, in the engaged position, the engine torque is transmitted from the drive shaft to the driven shaft. The clutch device is housed in a clutch bell extending between the engine block and the gearbox.

It is usual that the assembly of the elements of the clutch device generates an unbalance, that is to say that the center of gravity of the clutch device does not pass through its axis of rotation. The unbalance of a mechanism may be caused by an offset of the diaphragm, due to the play and tolerance between the diaphragm and centering rivets of the diaphragm. As such unbalance results, in operation, by a very large load of the bearings and considerably reduces the driving comfort, it is necessary to rebalance the clutch device by reducing the center of gravity of the clutch device on its rotation axis. Such an operation is usually called an unbalance, or rebalancing.

In the state of the art, it is known to determine the unbalance and then add on the clutch device one or more balancing masses positioned so as to compensate for unbalance and restore the balance of the device. The balancing masses can in particular be platelets which are fixed by welding on the clutch device. One of the drawbacks associated with the welding of wafers on the clutch device is a limitation of the maximum weight of each wafer, in particular because of the centrifugation stresses. Indeed, the centrifugal force acting on a wafer can cause it to tear if it has too much mass. In addition, the welding efficiency depends on the material being welded. By way of example, such balancing masses are described in particular in document FR2853374.

Furthermore, it is also disclosed in document FR2852644, to determine the unbalance and rebalance the device by removing material balancing elements previously fixed on the clutch device. The balancing elements extend radially outwardly from the cover of the clutch device, between said cover and the clutch housing. The balancing elements are elements made by folding or cutting a sheet. However, the realization of sheet metal balancing elements does not make it possible to manufacture masses of complex shape. Therefore, given the congestion constraints between the cover and the clutch bell, the balancing elements do not have a quantity of material, capable of being removed, sufficient to rebalance the unbalance, in case of strong imbalance.

Object of the invention

An idea underlying the invention is to provide a clutch device equipped with balancing elements that are particularly simple to perform and have a significant unbalance capacity.

According to one embodiment, the invention relates to a friction clutch device comprising:

a cover adapted to be rotated about an axis X, and a plurality of balancing elements fixed on the cover, the balancing elements being evenly distributed around the axis X and being each fixed on the cover by a fixing member,

each balancing element being made by sintering and comprising:

- A support plate resting against the cover and having a passage hole of the fastener; and

machinable excrescences protruding from said sole.

Thus, the balancing elements can be directly attached to a part of the clutch device. Thus, the balancing elements being made by sintering, they can have complex geometric shapes adapted best to the space available between the cover and the clutch bell and thus presented, in a small space, a quantity of machinable material sufficient to re-balance important imbalances.

According to other advantageous embodiments, such a friction clutch device may have one or more of the following characteristics:

the bearing plate of each balancing element comprises an anti-rotation pin inserted in a dedicated orifice of the lid. Thus, no rotation play will be possible between the balancing elements and the rivets during the rotation of the clutch device.

each balancing element has a plane of symmetry which passes through the axis X of rotation of the lid and by the fixing member.

each balancing element comprises two protuberances projecting from the soleplate and extending on either side of the passage orifice of the fastener. Thus, the protuberances being projecting, it is possible to remove the material easily by machining.

the protuberances each have a bevelled front face so that the axial dimension of the protrusions decreases in the radial direction, from the inside to the outside. the protuberances each have an external lateral face, defining an edge of the balancing element, said external lateral faces being bevelled so that the circumferential dimension of the excrescences decreases in the radial direction, from the inside to the outside. Thus, the geometric shapes of the sintered balancing element are best adapted to the space available between the cover and the clutch bell. the protuberances of each balancing element protrude radially.

the protuberances of each balancing element protrude axially.

the fixing member is a rivet passing through the orifice of the balancing element and having, on the one hand, an intermediate shoulder and, on the other hand, a rivet head, the intermediate shoulder; and the rivet head sandwiching the balancing member, thus the rivet and the balancing member form a pre-assembled assembly arranged to be fixed to the lid in a single step.

the balancing element is formed by sintering a steel, which makes it possible in particular to manufacture a balancing element having complex geometric shapes at a lower cost.

the steel has a density of between 6.8 and 7.2 g / cm ³ , in order to allow sintering to manufacture homogeneous balancing elements.

- The fixing member of each balancing element on the lid is further intended to ensure a fixing of the lid on a reaction plate. Thus, the number of necessary assembly steps is limited.

the cover comprises a radially oriented front bottom, an axially extending skirt rearwardly and fixing lugs intended to secure the cover to a reaction plate, the lugs extending radially projecting towards the rear; outside from an edge of the outer skirt and each being equipped with a through hole of the fastener ensuring the attachment of the balancing element on the cover and the attachment of the cover on a tray of reaction.

- The friction clutch device further comprises, housed inside the lid, a pressure plate, integral in rotation with the lid and axially movable relative thereto, a friction disc having a hub adapted to be secured in rotation to an input shaft of a gearbox and an annular diaphragm which is on the one hand, hinged against the bottom of the lid and on the other hand resting on the pressure plate.

According to one embodiment, the invention provides a motor vehicle equipped with a clutch device mentioned above.

According to one embodiment, the invention provides a method of balancing a clutch device comprising:

A step of measuring the unbalance;

A balancing step in which the excrescences of one or more balancing elements are machined according to the unbalance measured.

An idea underlying the invention is to provide a set of balancing elements, intended to rebalance a clutch device without the disadvantages of the prior art. An idea underlying the invention is to increase the total disbudding capacity of the mechanism at the end of the production line. An idea underlying the invention is to manufacture by sintering a balancing element and rivet on a part of the clutch device. An idea underlying the invention is that the geometry of the sintered balancing element is adjustable depending on the environment in which the clutch device is integrated.

The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly in the course of the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes. with reference to the appended figures.

In these figures:

• Figure 1 is a front view of a clutch device equipped with balancing elements.

FIG. 2 is a sectional view along the axis 11-11 of the clutch device of FIG. 1, with an enlargement at the level of the balancing element.

FIG. 3 is a perspective view of a balancing element fixed by a rivet on the cover and on the intermediate reaction plate of the clutch device of FIG. 1. • Figure 4 is a perspective view of an assembly formed by a balancing element and a rivet.

• Figures 5a and 5b are front and top views of the assembly formed by a balancing element and a rivet.

Figures 6a and 6b are respectively a sectional view and a front view of a rivet for fixing a balancing element.

• Figures 7a and 7b are respectively a sectional view and a detailed view illustrating the assembly formed by a balancing element and a rivet.

• Figure 7c is a sectional view of a rivet for fixing a balancing element according to another embodiment.

• Figures 8a, 8b and 8c are a set of front views, in section, and in perspective of a lug of the cover of the clutch device.

FIGS. 9a, 9b and 9c are respectively rear, sectional and perspective views of a balancing element of the clutch device intended to be positioned on the lug illustrated in FIGS. 8a, 8b and 8c.

Detailed description of embodiments

In the description and the claims, the terms "external" and "internal" as well as the "axial" and "radial" orientations will be used to designate, according to the definitions given in the description, elements of the clutch device. By convention, the "radial" orientation is directed orthogonal to the axis X of rotation of the clutch device determining the "axial" orientation and, from the inside towards the outside away from said axis X, the "Circumferential" orientation is directed orthogonally to the X axis of rotation of the clutch device and orthogonal to the radial direction. The terms "external" and "internal" are used to define the relative position of one element with respect to another, with reference to the X axis, an element close to the axis is thus termed internal by opposition to an external element located radially at the periphery. Furthermore, the terms "rear" AR and "front" AV are used to define the relative position of one element relative to another in the axial direction, an element intended to be placed close to the engine being designated by the rear and an element intended to be placed close to the gearbox being designated by before.

With reference to FIGS. 1 and 2, a clutch device of the double clutch type is shown. A dual clutch 1 for a motor vehicle is intended to ensure the coupling between the crankshaft of the engine and two gearbox input shafts. The double clutch 1 is disposed inside a clutch bell 9 which is, on the one hand, fixed to the engine block and, on the other hand, to the gearbox.

It comprises a central reaction plate 5 rotating about a reference geometric axis X and intended to be fixed on a flywheel, fixed at the end of the crankshaft. A first 7 and a second 8 pressure plates are located axially on either side of the central reaction plate 5. The first 7 and second 8 pressure plates are axially movable in translation relative to the central reaction plate 5 .

The double clutch 1 also comprises first and second friction discs 10, 11. The friction discs 10, 11 are provided with friction linings and each comprise a splined hub for cooperating with splines formed at the end of one of the input shafts of the gearbox.

The double clutch comprises a first diaphragm 27 which is, on the one hand, pivotally mounted against the bottom of the cover 2 and, on the other hand, bears against the pressure plate 8. The diaphragm 27 cooperates with a clutch abutment , not shown, which is able to rotate it. The pivoting of the diaphragm 27 causes the pressure plate 8 to move between an engaged position in which the friction disc 11 is clamped between the pressure plate 8 and the central reaction plate 5 and a disengaged position.

Furthermore, the double clutch comprises a second diaphragm 28 which forms a lever and cooperates with a clutch abutment, not shown. The second diaphragm 28 is on the one hand pivoted against the bottom of the cover 2 and on the other hand bears against a movable cover 29. The movable cover 29 is able to transmit the movement of the second diaphragm 28 to the pressure plate 7 of the such that the pivoting of the diaphragm 28 causes the pressure plate 7 to move between an engaged position in which the friction disc 10 is clamped between the pressure plate 7 and the intermediate reaction plate 5 and a disengaged position.

By way of example, such a double clutch is described in more detail in the document FR2995376.

The lid 2 has a front bottom 26 of radial orientation and a skirt 25 extending axially rearwardly. The lid 2 is equipped with flaps 3 radially outward, from the rear edge of the skirt. The tabs 3 allow attachment of the lid 2 to the intermediate reaction plate 5. The tabs 3 are here spaced a constant angular distance on the outer periphery of the lid 2. As shown in Figure 1, the lid 2 is here equi- three legs 3, angularly spaced from each other by 120 °.

Rivets 13 pass through orifices formed in the lugs 3 of the lid 2 and thus making it possible to fix the lid 3 on the intermediate reaction plate 5. Furthermore, a balancing element 12 is fixed by means of said rivet 13 on each of the lugs 3. The rivets 13 pass through orifices provided in the balancing elements 12 and thus make it possible to secure the balancing element 12, the lid 2 and the central reaction plate 5.

The balancing element 12 is formed by a method of sintering a powder.

In one embodiment, the balancing element 12 is obtained by a sintering process of a steel powder. The steel is for example a steel Fe-0.5C, that is to say between 0.3 and 0.7% by weight of carbon. Such a steel further comprises a total content of residual additional elements of less than 1%. The density of the steel obtained by sintering is typically between 6.8 and 7.2 g / cm ³ . By way of example, it will be possible, in particular, to use the steel referenced D01 according to the DIN-SINT standard, F-05-170 according to the ISO standard, or F-0005-25 according to the MPIF standard. Such a steel powder D 01 has the particular advantage of allowing the manufacture by sintering of homogeneous balancing elements.

The sintering process comprises two steps, namely a first step of filling a mold with powder and a second step of compressing the powder. The mold includes a die defining a cavity for receiving the powder and a punch for compressing the powder within the die. In the first filling step, a mixture comprising metal powder, additives and lubricants, used to facilitate the compression of the powder, is introduced into the matrix. Subsequently, during its compression, the powder is subjected to a thermal cycle for the generation of welds between the powder grains. During the first phase of the thermal cycle, the powder is heated to a temperature sufficient to evaporate the lubricant and obtain a homogeneous temperature. Then, in a second phase of the thermal cycle, the compressed powder is brought to the sintering temperature, slightly below the melting temperature of the material. The sintering temperature is generally of the order of 1120 ° C. Finally, in a final phase of the thermal cycle, the balancing element 12 thus formed is cooled slowly.

This sintering method makes it possible in particular to manufacture a balancing element 12 having complex geometric shapes at a lower cost. The geometric shapes of the balancing element 12 can thus be adapted as best as possible to the space available between the cover 2 and the clutch bell.

With reference to FIGS. 3, 4, 5a and 5b, it is observed that the balancing element 12 comprises a sole plate 18 resting against the lug 3 of the lid 2. The soleplate 18 is traversed by an orifice through which passes the rivet 13. The rivet 13 has a head 21 abutting on the sole plate 18 of the balancing element 12. The end of the rivet has a frustoconical shape 20.

The balancing element 12 also comprises two excrescences 16, 17, machinable, extending on either side of the orifice. The balancing element 12 thus has a U shape, where the branches of the U are formed by the protuberances 16, 17. The protuberances 16, 17 are symmetrical with respect to a plane of symmetry 21 passing through the center of the orifice and by the axis of rotation X. The protuberances 16, 17 here protrude axially rearwards relative to the sole 18.

The protuberances 16, 17 have a beveled front face 14 so that the axial dimension of the protuberances 16, 17 decreases in the radial direction, from the inside to the outside. In other words, the protuberances 16, 17 have a shape such that the radial dimension of the protrusions decreases from the rear to the front. In addition, the protuberances 16, 17 also have bevelled outer side faces 15 such that the circumferential dimension of the protuberances 16, 17 decreases in the radial direction from the inside to the outside.

The beveled shapes 15, 14 of the protuberances 17, 16 of the balancing element 12 thus make it possible to best adapt the shape of the balancing element 12 to the shape of the clutch bell 9. balancing elements 12 have, in a small space, a mass, capable of being machined, important for compensation of strong imbalances.

Furthermore, the sole 18 of the balancing element 12 is provided, on its bearing surface against the lug 3 of the cover, with an anti-rotation pin 19 intended to fit into a dedicated orifice of the cover 2 of the clutch device 1 so preventing the balancing element 12 from pivoting about the axis formed by the rivet rod 13.

Figures 6a and 6b illustrate a rivet 13 for fixing the balancing element 12 to the lid 2 according to a first embodiment. This rivet 13 has a frustoconical end 20. This rivet 13 also has a rivet head 21. In addition, this rivet has a groove 22 formed in the rivet head 21 at the edge and around the rivet pin 13. FIGS. 7a and 7b illustrate the rivet 13 inserted in a balancing element 12. The balancing element 12 abuts on the rivet head 13.

Referring to FIG. 7c, another embodiment of a rivet is described in which an annular bead 23, formed on the rod of the rivet 13, abuts against the balancing element 12 so that the balancing element 12 is sandwiched between the annular bead 23 and the rivet head 21. Thus, the rivet 13 and the balancing element 12 form a pre-assembled assembly arranged to be fixed on the cover 3 one step.

With reference to FIGS. 8a, 8b, 8c and 9a, 9b and 9c, a tab 3 of the cover 2 of a clutch device will be described in relation to a balancing element 12.

The tab 3 extends radially protruding from the cover 2 from the axially oriented skirt 25 of the cover. The lid has a bottom 26. The lug 3 has a cylindrical through-orifice 24 and a blind orifice 23.

The balancing element 12 comprises a cylindrical through-hole and a lug 19. The orifice 24 of each lug 3 is intended to be positioned opposite the orifice 30 of the balancing element for allow a rivet to fix the two parts together by inserting into the two orifices.

Moreover, the lug 19 is intended to fit into the blind hole 23 of the lug 3 of the lid 2. Thus, the two parts being retained by the lug 19, the balancing element 12 can not pivot about the axis of its cylindrical through hole 24 relative to the tab 3 of the lid 2.

The method for balancing the clutch device described above is as follows. In a first step, when assembling the different disks on the cover 2, the balancing elements 12 are fixed by the rivets 13 on the lugs 3 of the cover 2. Then, when the balancing elements 12 are fixed, it is determined the unbalance of the clutch device around its axis of rotation X. Finally, according to When the determined unbalance is determined, the clutch device is rebalanced by removing material from one or more of the balancing elements. The removal of material may be carried out by any suitable machining means, and in particular by milling.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it comprises all the technical equivalents of the means described and their combinations if those are within the scope of the invention.

In particular, in another embodiment, the balancing elements 12 are fixed on the axially oriented skirt of the cover 2 in the radial direction and extending outwards. Rivets make it possible to fix the balancing elements by passing through orifices formed directly in the skirt of axial orientation.

In another embodiment, the rivet 13 fixes a balancing element 12 on the lid 2 independently of the fixing of the lid 2.

In another embodiment, the tabs may be replaced by a flange extending around the entire periphery of the lid 3. Such a flange has holes passing through regularly distributed around the axis X and each allowing the passage of a rivet 13, on the one hand, fixing the lid to the central reaction plate 5 and, on the other hand, fixing a balancing element 12 to the lid 3.

Furthermore, we note that the balancing elements 12 can also be attached to a cover 2 of a single clutch device. In such a case, the balancing elements 12 may in particular be fixed on the cover 2 of the clutch device via the rivets for fixing the clutch device on the flywheel.

The use of the verb "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or steps other than those set out in a claim. The use of the indefinite article "a" or "an" for an element or a step does not exclude, unless otherwise stated, the presence of a plurality of such elements or steps.

In the claims, any reference sign in parentheses can not be interpreted as a limitation of the claim.

Claims

1. Friction clutch device (1) comprising:

a cover (2) adapted to be rotated about an axis X, and a plurality of balancing elements (12) fixed to the cover, the balancing elements being evenly distributed about the axis X and each being secured to the lid by a fastener (13),

each balancing element (12) being made by sintering and comprising:

a bearing plate (18) resting against the cover and having a through hole (30) of the fastener; and

machinable protrusions (16, 17) projecting from said soleplate.

2. Friction clutch device (1) according to claim 1, wherein the support plate (18) of each balancing element comprises an anti-rotation pin (19) inserted into a dedicated hole of the cover.

3. friction clutch device (1) according to claim 1 or 2, wherein each balancing element (12) has a plane of symmetry which passes through the axis X of rotation of the lid and by the body of fixing (13).

4. Friction clutch device (1) according to any one of claims 1 to 3, wherein each balancing element (12) comprises two protuberances (16, 17) projecting from the sole (18) and s extending on either side of the passage opening of the fastening member (13).

5. Friction clutch device (1) according to any one of claims 1 to 4, wherein the protuberances (16, 17) each have a bevelled front face (14) so that the axial dimension of the growths ( 16, 17) decreases in the radial direction, from the inside to the outside.

The friction clutch device (1) according to any one of claims 1 to 5, wherein the protuberances (16, 17) each have an outer lateral face (15), defining an edge of the element of balancing, said outer side faces (15) being beveled such that the circumferential dimension of the protuberances (16, 17) decreases in the radial direction, from the inside to the outside.

7. Friction clutch device (1) according to any one of claims 1 to 6, wherein the protrusions (16, 17) of each balancing element (12) project radially.

8. Friction clutch device (1) according to any one of claims 1 to 6, wherein the protrusions (16, 17) of each balancing element (12) project axially.

The friction clutch device (1) according to any one of claims 1 to 8, wherein the fastening member (13) is a rivet passing through the orifice (30) of the clutch element. balancing and having, on the one hand, an intermediate shoulder (23) and, on the other hand, a rivet head (21), the intermediate shoulder (23) and the rivet head (21) sandwiching the balancing element (12).

10. A friction clutch device (1) according to any one of claims 1 to 9, wherein the balancing element (12) is formed by sintering, a steel.

1 1. A friction clutch device (1) according to claim 10, wherein the steel has a density of between 6.8 and 7.2 g / cm ³ .

12. A friction clutch device (1) according to any one of claims 1 to 11, wherein the fastener (13) of each balancing element (12) on the cover (2) is furthermore intended to ensure a fixing of the lid on a reaction plate.

The friction clutch device (1) according to claim 12, wherein the cover (2) has a radially oriented front end (26) and a rearward axially extending skirt (25). wherein the lid (2) has fastening tabs (3) for securing the lid to a reaction plate (5), the tabs extending radially outwardly projecting from an edge of the skirt and each being equipped with a through hole (24) of the fixing member (13) ensuring the fixing of the balancing element (12) on the cover (2) and the fixing of the cover (2) on a reaction plate (5).

14. Friction clutch device (1) according to any one of claims 1 to 13, further comprising, housed inside the cover (2), a pressure plate (7, 8), fixed in rotation of the cover (2) and axially movable relative thereto, a friction disc (11) having a hub adapted to be secured in rotation to an input shaft of a gearbox and an annular diaphragm (27) which is on the one hand mounted hinged against the bottom of the lid and on the other hand resting on the pressure plate (7, 8).

15. Motor vehicle equipped with a clutch device (1) according to any one of claims 1 to 14.

16. A method of balancing a clutch device (1) according to any one of claims 1 to 14, comprising:

A step of measuring the unbalance;

A balancing step in which the protuberances (17, 16) of one or more balancing elements (12) are machined according to the unbalance measured.