FR3079010A1 - PENDULAR DAMPING DEVICE - Google Patents

Abstract

Pendulum damping device intended to be integrated in a transmission chain of a motor vehicle, in particular in a clutch, comprising: - a support (20) having an axis of rotation, in which a support window is provided, and defining a cam path, - an oscillating weight guided in oscillation relative to the support and comprising: - first and second flyweights, - a spacer (12) matching said flyweights through the support window, - a cam follower (14) adapted to cooperate with the cam path to limit the radial displacement of the oscillating mass relative to the support.

Description

PENDULUM DAMPING DEVICE

Technical area

The present invention relates to a pendulum damping device, in particular for a clutch of a motor vehicle transmission system.

State of the art

A pendulum damping device is conventionally used to filter vibrations due to acyclisms in the engine of a motor vehicle. Indeed, the movements of the cylinders of an internal combustion engine generate acyclisms which vary in particular according to the number of cylinders. These acyclisms are capable of generating in turn vibrations which can pass into the gearbox and cause shocks and undesirable noise pollution. It is therefore preferable to provide a vibration filtration device.

The pendulum damping device is conventionally rigidly fixed, by means of rivets, to a phasing washer of a torsion damping device, in particular to a clutch, a hydrodynamic torque converter or a double wet or dry clutch. . Such a torsional damping device is for example known as a double damping flywheel.

Conventionally, the pendulum damping device comprises an annular support intended to be driven in rotation and several pendulum oscillating masses, mounted oscillating on the support around an axis parallel to the axis of rotation of the support. The movement of an oscillating mass relative to the support is generally guided by two rolling members each cooperating with a rolling track of the support and a rolling track of the oscillating mass. The rolling tracks of the support and of oscillating mass extend so that in service the rolling members are in centrifugal and centripetal support, respectively, on said tracks.

An oscillating weight is conventionally constituted by a pair of weights, sandwiching the support and rigidly joined together, generally by means of a spacer. The flyweights can be riveted to the spacer or they can have windows in which the spacer extends.

When the pendulum damping device rotates at reduced speed, typically at less than 800 revolutions / min, in particular when starting, when the vehicle is slowing down, when the engine is stopped or when changing gear ratio, the centrifugal force exerted on the oscillating masses is reduced and the latter therefore tend to approach the axis of rotation. The contact of the running gear with the running tracks can thus be interrupted, which leads to undesirable noise and to shocks likely to reduce the service life of the pendulum damping device. In particular, the running gear is a major source of unwanted noise.

It is known from application FR 3 046 649 in the name of the Applicant a pendulum damping device comprising a spring limiting the displacements of the oscillating mass in the radial direction during a slowing down of the rotation of the pendulum damping device. This solution is not entirely satisfactory.

The object of the invention is therefore to provide a more efficient solution for reducing shock and unwanted noise.

Summary of the invention

To this end, the invention provides a pendulum damping device intended to be integrated in a transmission chain of a motor vehicle, in particular in a clutch, comprising:

a support having an axis of rotation, in which a support window is provided, and defining a cam path, an oscillating mass guided in oscillation relative to the support and comprising:

first and second weights, a spacer matching said weights through the support window, a cam follower adapted to cooperate with the cam track in order to limit the radial movement of the oscillating mass relative to the support.

In this way, the cam follower limits the radial clearance of the oscillating mass relative to the support, and therefore the height of fall of the corresponding mass. The noise is thus reduced when the vehicle engine is stopped when the oscillating masses are no longer centrifuged, or even at low engine speed, when the centrifugal effect is no longer sufficient to compensate for the weight of each oscillating mass.

A device according to the invention may also include one or more of the following optional characteristics:

- The cam follower is configured to be selectively in support or at a distance from the cam path, depending on the speed of rotation of the support; Thus, when the oscillating mass is supported by centrifugal force (that is to say when the speed of rotation of the support is sufficient to keep the oscillating mass pressed radially outwards) the cam follower does not exert constraints on the displacement of the oscillating mass. However, when the oscillating mass is not supported by the centrifugal force, it tends to approach the axis of rotation. The cam follower then prevents the oscillating mass from undergoing a significant radial drop capable of generating undesirable noises, since the cam follower abuts against the support.

- The contact between the cam follower and the cam path is a centripetal support;

- The cam follower, preferably rigidly secured to the spacer, comprises at least one tab preferably extending transversely and carrying a finger, preferably axial, shaped to ensure said cooperation;

- The cam follower has two legs each extending against one face of the support, and a common finger said to the two said legs;

- The two tabs each extend against a large face of the support so as to close, partially or completely, the support window;

- The cam path is shaped so that the maximum spacing with the finger is less than 10 mm (millimeters), preferably less than 5 mm, preferably less than 2 mm;

- The leg (s) is or are shaped so as not to come into contact with a rolling member during an oscillation of the oscillating mass;

- The cam path is defined by an outer peripheral edge of the support or by an edge of a cutout of the support radially outer or radially inner relative to the support window, or by a bead projecting axially from the support;

- The cutout is a curved slot, preferably substantially in the shape of an arc of a circle or an arc of an ellipse, opening towards the axis of rotation, that is to say the one (s) center (s) of curvature are radially inside;

- The cut is a slit having a left shape, that is to say a shape similar to the path of the center of gravity of the first and / or second weights;

- The slot has a constant width, preferably substantially equal to the width of a finger of the cam follower which is housed therein, the maximum spacing between the edge of the slot and the finger is preferably less than 2 mm.

The invention also relates to a component for a transmission system of a motor vehicle, the component being in particular a double damping flywheel, a hydrodynamic torque converter or a friction clutch disc, comprising a pendular damping device according to the invention.

Another subject of the invention, according to another of its aspects, is a vehicle powertrain comprising:

- a vehicle propulsion thermal engine, and

- a component for a transmission system according to the invention.

Brief description of the figures

Other characteristics and advantages of the invention will become apparent on reading the description which follows and on examining the appended drawing in which:

- Figure 1 shows a pendulum damping device;

- Figure 2 is a detailed view of the device of Figure 1 corresponding to the back of the device as shown in Figure 1;

- Figures 3a and 3b show a second embodiment of the device according to the invention;

- Figures 4a and 4b illustrate a third embodiment of the device according to the invention.

For each of FIGS. 3 and 4, the indexed figure "a" represents the device according to the invention in a centered position relative to its amplitude of oscillation and the indexed figure "b" represents the same device in extreme oscillation position .

In the various figures, identical references are used to designate identical or analogous members.

Definitions

Unless otherwise indicated, "axially" means "parallel to the axis X of rotation of the support";

"Radially" means "along a transverse axis intersecting the axis of rotation of the support";

"Angularly" or "circumferentially" means "around the axis of rotation of the support";

"Transversely" means "perpendicular to the X axis".

The thickness is measured according to Tax X.

"Centrifugal support" means a support force comprising a component oriented away from the X axis.

By "centripetal support" is meant a support force comprising a component oriented towards the X axis.

"Motor vehicle" means not only passenger vehicles, but also industrial vehicles, which includes heavy goods vehicles, public transport vehicles or agricultural vehicles.

By “oscillating mass”, or “pendulum body”, is meant a mass which is mounted so as to oscillate on the support in response to acyclisms of the vehicle engine. An oscillating mass is conventionally constituted by a pair of weights, or "pendulum masses", extending so as to sandwich the support and rigidly joined together. An oscillating mass can also be constituted by a single counterweight.

Two pieces are said to be "rigidly attached" or "paired" when they are permanently immobilized relative to one another. This immobilization can result from a fixing of the first part on the second part directly or by means of one or more intermediate parts.

The rest position of the device is that in which the oscillating masses are subjected to a centrifugal force, but not to torsional oscillations originating from the acyclisms of the heat engine.

The oscillating masses are said to be "supported by centrifugal force" when the speed of rotation of the support is sufficient to keep the oscillating masses pressed radially outward against the rolling members, and by their means against the support.

Unless otherwise indicated, the verbs "to include", "to present" or "to understand" must be interpreted broadly, that is to say without limitation.

detailed description

A pendulum damping device 10 is shown in FIG. 1. As illustrated, it comprises four oscillating masses mounted on a support 20 of axis X, each oscillating mass comprising first and second flyweights 24, paired through 'a spacer 12. One of the weights is not shown in order to reveal a support window 22, passing through the support according to its thickness.

The support is conventionally constituted by a cut metal sheet, generally made of steel, of a thickness typically less than 10 mm, preferably less than 9 mm, preferably less than 8 mm.

In the device of FIG. 1, each support window 22 houses a spacer 12 integrating two weights 24, as well as two rolling members 18, here rollers. An oscillating mass is conventionally mounted to oscillate on the support 20 by means of the two rolling members 18 which pass through the support window 22 and guide the movement of the oscillating mass relative to the support 20 while rolling on a support track and a spacer track.

The oscillating masses are preferably distributed equi-angularly around the axis X. Preferably, their number is greater than 2 and / or less than 8. The device can in particular comprise three, four, five or seven oscillating masses.

Figure 2 is a detailed view of the device of Figure 1 showing the axial face opposite to that visible in Figure 1. One of the two weights 24 is not shown in order to reveal in particular the cam follower 14 according to l 'invention.

The cam follower 14 is rigidly secured to the spacer 12: in this embodiment, it takes advantage of the fact that the flyweights 24 are riveted on the spacer 12 to insert the cam follower 14 between a flyweight and the spacer. In this way, the cam follower 14 is also riveted to the spacer 12.

Preferably, the cam follower 14 is made of thin metal sheet with a thickness of less than 3 mm, preferably less than 2 mm.

In this first embodiment, a cam follower 14 has two legs 16. Each of these legs 16 extends radially outward and has at its end a finger 25 extending in the axial direction. The oscillating weight may include two cam followers 14, opposite one another and arranged on either side of the spacer. A single finger 25 can connect two legs 16 opposite one another to the two cam followers

14.

When the oscillating mass is supported by centrifugal force, the fingers are no longer in contact with the support during the oscillation of the oscillating mass. The cam path is preferably shaped so that the distance between the finger and the cam path remains less than mm. In other words, at sufficient speed of rotation of the support, the cam follower 14 does not interfere with the oscillation of the oscillating mass and the movement of the fingers follows the curvature of the cam path of the support. There is no contact between the fingers and the support.

When the speed of rotation of the support decreases and becomes insufficient for the oscillating mass to be supported by centrifugal force, that is to say pressed against the rolling members, the oscillating masses tend to approach radially from the axis X The finger (s) 25 then come into contact with the cam track 26, in this case with the outer peripheral edge of the support 20. This is conventionally the case when the speed of rotation of the support becomes less than 800 revolutions / minute .

The fingers 25 thus act as stops and make it possible to limit the height of the radial fall of the oscillating mass. This avoids sudden impacts between the support and the oscillating weight.

In the same way, since the radial displacement of the oscillating mass is small thanks to the invention, the rolling members have only little free space. The shocks caused by the chaotic movement of the running gear are therefore also limited. The noise caused by these various shocks is therefore significantly reduced thanks to the invention.

The realization of the cam path on the outer peripheral edge of the support is advantageous, since the machining operations on this edge are relatively easy to implement.

it is conceivable that the legs 16 of the cam follower 14 also exert a function of axial guiding of the rolling members, in order to limit their axial play. The rolling members are in fact liable to be subjected to shocks in the axial direction due to the axial mounting clearance. The invention can advantageously limit these shocks and the associated noises.

Figures 3a and 3b illustrate a second embodiment of a damping device according to the invention. In this embodiment, the cam follower 14 has only one lug 16 and the cam path is defined by the edge of a slot. The slot can be separate from window 22.

As illustrated in FIGS. 3a and 3b, the shape of the slot is adapted to allow the oscillation of the oscillating mass without the cam follower 14 coming into contact with the support.

In this embodiment and as visible in FIG. 3b, an oscillating mass comprises two cam followers 14, of identical shape, axially opposite one another on each side of the spacer 12. In order to improve the stiffness of the ends of the legs of each cam follower, it is advantageous that the latter meet within the slot of the support. They then have a common finger.

Figures 4a and 4b show a third embodiment. The cam path 26 of the support is here produced radially towards the inside of the support relative to the position of the support window. As in the embodiment of Figures 3a and 3b, a cam follower 14 has only one lug 16 and an oscillating mass has two cam followers of the same shape and located axially opposite one another.

The means of producing the stop for the cam follower on the support is not limited to the means illustrated in these examples, namely a finger at one end of the tab and extending axially. It is also conceivable that the support has an axial protuberance and that a lug of the cam follower comes to bear on this protuberance when the oscillating mass is not supported by centrifugal force.

Of course, the invention is not limited to the embodiments described and shown, provided for illustrative purposes only. In particular, the number of cam followers on each oscillating weight, the number of legs per cam follower, the shape of the cam tracks are not limiting. The different embodiments could also be combined.

Claims (10)

1. A pendulum damping device intended to be integrated in a transmission chain of a motor vehicle, in particular in a clutch, comprising: a support (20) having an axis of rotation (X), in which a support window (22) is provided, and defining a cam path (26), - an oscillating weight guided in oscillation with respect to the support and comprising: first and second weights (24), a spacer (12) matching said weights through the support window, a cam follower (14) adapted to cooperate with the cam track in order to limit the radial movement of the oscillating mass by support. 2. Device according to claim 1, in which the cam follower is adapted to be selectively in support or at a distance from the cam track, as a function of the speed of rotation of the support (20). 3. Device according to the immediately preceding claim, wherein the contact between the cam follower and the cam track is a centripetal support. 4. Device according to any one of the preceding claims, in which the cam follower comprises at least one tab (16) carrying a finger (25) shaped to ensure said cooperation. 5. Device according to the immediately preceding claim, the cam follower comprising two legs each extending against one face of the support, and a finger common to the two said legs. 6. Device according to any one of the two immediately preceding claims, wherein the lug (s) is or are shaped so as not to come into contact with a rolling member during an oscillation of the oscillating mass. 7. Device according to any one of the three immediately preceding claims, in which the cam path (26) is defined by an outer peripheral edge of the support or by an edge of a cutout of the support radially exterior or radially interior with respect to the support window, or by a bead projecting axially from the support. 8. Device according to the immediately preceding claim, wherein the cutout 5 is a curved slot opening towards the axis of rotation (X). 9. Device according to the immediately preceding claim, wherein the slot has a constant width, the maximum spacing between the edge of the slot and a finger of the cam follower which is housed therein being preferably less than 2 mm. 10. Component for a motor vehicle transmission system, the component 10 being in particular a double damping flywheel, a hydrodynamic torque converter or a friction clutch disc, comprising a pendular damping device according to any one of the preceding claims.