FR3074869A1 - PENDULAR DAMPING DEVICE - Google Patents

Abstract

A pendulum damping device (1, 20, 21) for transmitting a motor vehicle of the type comprising: - a support (2) driven in rotation about an axis (XX ') of said transmission; - at least one pendulum body (3, 6, 14, 23) comprising at least one pendulum mass (3) and rolling members (6, 14, 23), said pendulum body (3, 6, 14, 23) being movable relative to said support (2), said rolling members (6, 14, 23) cooperating with: - inner raceways (7) integral with said pendulum mass (3) and associated with said rolling members (6, 14) , 23); external running tracks (8) secured to said support (2) and associated with said rolling members (6, 14, 23); characterized in that said pendulum mass (3) or said support (2) comprises at least one magnet (9) facing said rolling members (6, 14, 23) during said movement.

Description

- 1 PENDULUM DAMPING DEVICE

TECHNICAL FIELD OF THE INVENTION.

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

TECHNOLOGICAL BACKGROUND OF THE INVENTION.

Such a device, also called a pendulum oscillator or pendulum, is in particular intended to equip a transmission of a motor vehicle.

In a motor vehicle transmission, at least one torsional damping system is generally associated with a clutch capable of selectively connecting the engine to a gearbox, such as a friction clutch or a hydrokinetic coupling device comprising a locking clutch.

Indeed, an internal combustion engine generates acyclisms due to the successive explosions in the engine cylinders, these acyclisms varying in particular depending on the number of cylinders.

The damping system, which conventionally includes springs and friction elements, therefore has the function of filtering torsional vibrations due to the rotational acyclisms of the engine and intervenes before the transmission of engine torque to the gearbox. This is to prevent such vibrations from entering the transmission and causing unwanted impact, noise and noise.

In order to further improve filtration, it is known to use a pendulum damping device, in addition to the usual damping system.

For example, patent application FR3037114, in the name of the applicant, discloses a device for damping torsional oscillations comprising pendulum damping means constituted by pendulum masses movably mounted on an annular support arranged between an element torque input and a torque output element, and rotated about its axis.

In reaction to irregularities or acyclic rotation, each mass oscillates in a pendulum. The oscillation frequency of each mass is proportional to the speed of rotation of the motor shaft, the corresponding multiple being able by

-2 example take a value close to the rank of the preponderant harmonic of the vibrations responsible for the strong irregularities of rotation in the vicinity of the idle.

In this example, rolling tracks associated with rolling members allow a displacement in translation of the centers of gravity of the pendular masses and a rotational movement of these pendular masses around their centers of gravity.

During normal operation of the pendulum damping device, strong mechanical stresses are exerted on the running gear by the pendulum masses subjected to a centrifugal force and by the support which exerts a radial retaining force, keeping the assembly in contact .

On the contrary, in certain configurations of the device, in particular when the engine is stopped or when the speed of rotation of the transmission is slowed down, the rolling members drop and cause undesirable noise when they come into contact with the support. .

These same rolling members can also come into axial contact with the pendular masses, these shocks also being sources of undesirable noise.

These unwanted noises are partially covered by the noise of the heat engine, and this is acceptable for most customers, but not for demanding customers.

In addition, in the case of a hybrid vehicle, at low speed, unwanted noise can occur in many circumstances. An electric motor creates less noise that can mask unwanted noise than a heat engine, and the noise emerging from the pendulum damping device will seem more important, so that the end user will be disturbed. In these types of applications, all customers could consider this unwanted noise as unacceptable.

In order to overcome this drawback, the applicant proposes in the French patent application FR3039872 the use of composite bearing members, part of which is formed from a material of lower density compared to that of monoblock bearing members in steel. Lightened running gear allows a reduction in the intensity of the shocks and therefore leads to a reduction in unwanted noise.

However, a less dense material than steel, for example a plastic or an elastomer, can reduce the mechanical resistance of the rolling members.

In addition, the manufacture of composite rolling members by overmolding, welding or gluing can be complex to implement.

GENERAL DESCRIPTION OF THE INVENTION.

The object of the present invention is therefore to produce a pendular damping device for the transmission of a motor vehicle free from the undesirable noise generated by the rolling members, without reducing the mechanical resistance of the latter and while preserving their ease of manufacture.

This pendulum damping device is of the type comprising:

- a support driven in rotation about a transmission axis;

at least one pendulum body comprising at least one pendulum mass and rolling members, the pendulum body being movable relative to the support, these rolling members cooperating with:

- internal raceways integral with the pendulum mass and associated with the running gear;

- external raceways integral with the support and associated with the running gear.

According to the invention the pendulum mass or the support comprises at least one magnet facing the rolling members during the movement.

According to the general principle of the invention, there is creation of a plating force which generates a hysteresis between the rolling member on the one hand and the pendulum mass or the support on the other hand. The rolling element is no longer free to move under its own weight when the speed of rotation of the support decreases below a threshold value.

According to the invention, under a magnetic attraction generated by this magnet, one of the opposite axial faces of each of the rolling members exclusively is in contact at least in part with the pendular mass or the support.

According to the invention, the pendulum mass advantageously comprises a countersink comprising the magnet. The pendulum mass can also further include a pad interposed between the magnet and the running gear. The shoe prevents metal / metal shocks between the pendulum mass and the support and / or between the magnet and the rolling element.

Preferably, this pad is made of plastic.

In a first embodiment of the pendulum damping device according to the invention, the rolling members are monobloc and made of a magnetic metal.

Preferably, the opposite axial faces of the rolling members each have a peripheral groove provided with an external flange having a sharp edge. A radius of said sharp edge may preferably be less than 0.3 mm.

In a second embodiment of the pendulum damping device according to the invention, the rolling members are composite with a central core made of a magnetic metal.

Preferably, in this second embodiment, the rolling members are formed of ceramic around a metallic axial ball.

In both embodiments of the pendulum damping device according to the invention, the magnet is advantageously formed of a magnetic pad, preferably made of ferrite.

In all of the above, the device may include two rolling members associated with the pendulum body. The device is then said to be "two-wire".

According to a first configuration of the device, each pendulum body can comprise two pendulum masses arranged on either side of the support. The pendulum masses can be matched by means of bearing spacers passing through the support slots.

According to a first variant, each running member is associated with a connecting spacer which defines the running track of the pendulum body. A common spacer can also be provided, the two rolling members then cooperate with said spacer formed in a single lumen.

The internal raceways can be formed by the spacer (s). The external raceways can be formed by the edge (s) of the light (s).

The running member can cooperate with the running track secured to the support and with the running track secured to the pendulum body only via its outer surface. Thus, the same portion of this outer surface can roll alternately on the rolling track secured to the support and on a rolling track secured to the pendulum body when the rolling member moves. The rolling element can then only be subjected to compression between the rolling tracks.

-5In this configuration, the connecting spacer is for example force fitted via each of its axial ends in openings made in the pendulum masses. Alternatively, the connecting member can be welded, riveted or screwed via its axial ends to each pendulum mass.

According to a second configuration of the device, each rolling member cooperates with two rolling tracks integral with the pendulum body, each rolling track being defined by the edge of a groove formed in one of the pendular masses. For each rolling member, the integral support raceway is defined by the edge of a cavity of the support separate from the slots through which the connecting spacers pass. The running gear and the connecting spacers are at a distance from each other.

According to this second configuration, each rolling member can then successively comprise axially:

- a portion cooperating with the internal raceway defined by the edge of the groove of a pendulum mass,

a portion cooperating with the external raceway defined by the edge of the support cavity, and

- a portion cooperating with the internal raceway defined by the edge of the groove of the other pendulum mass,

The portions of each rolling member can be successive cylindrical and of different radii.

In this second configuration, the connecting members are for example rivets, for example three.

According to a third embodiment, the pendulum body comprises a single central mass arranged between two flanges of the support. The flanges have grooves. The edges of the grooves define external raceways. The central mass defines a pendulum body cavity, the edge of which defines the internal raceway.

According to this third configuration of the device, each rolling member cooperates with two external raceways and with an internal raceway.

In the second and third modes, the magnets can be arranged in the grooves, which can then be blind.

-6The running gear may have axial shoulders which can be pressed by magnetic attraction against the flanges of the support or against the pendulum masses.

As a variant, pads can be arranged between the rolling members and the magnets in the grooves. The running gear can then be pressed against these pads. These few essential specifications will have made it obvious to those skilled in the art the advantages provided by the pendulum damping device according to the invention compared to the prior art in terms of the suppression of undesirable noise produced by the organs of bearings.

The detailed specifications of the invention are given in the description which follows in conjunction with the attached drawings. It should be noted that these drawings have no other purpose than to illustrate the text of the description and do not in any way constitute a limitation of the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS.

Figure 1 is an axial view of the entire pendulum damping device in the first embodiment of the invention.

Figure 2 is a sectional view along A-A of the pendulum damping device in the first embodiment of the invention shown in Figure 1.

Figure 3 is an exploded isometric view of a pendulum body of the pendulum damping device in the first embodiment of the invention shown in Figure 1.

Figures 4a and 4b are respectively isometric and diametral section views of a rolling member of the pendulum damping device in a particular variant of the first embodiment of the invention.

Figure 5 is a sectional view of the pendulum damping device in the particular variant of the first embodiment of the invention implementing the rolling member shown in Figures 4a and 4b.

Figure 6 is a partial sectional view of a pendulum damping device in another skidless embodiment of the invention.

Figure 7 is a partial sectional view of a pendulum damping device in the other embodiment without pad, in a variant where the pendulum masses are arranged between the two flanges of a support.

-7 DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION.

In a manner known per se, the pendulum damping device 1 according to the invention shown in FIG. 1 essentially comprises:

- An annular support 2 able to be driven in rotation about an axis XX ';

- pendulum masses 3 arranged on either side of the support 2 at its periphery.

These pendulum masses 3, of the general shape of a circular segment, are matched by means of connecting spacers 4 passing through slots 5 in the support 2.

They are movable by means of rolling members 6 constituted by rollers rolling, on the one hand, on internal rolling tracks 7 formed on the connecting spacers 4 and, on the other hand, by resting and rolling on external raceways 8 formed by edges of the lumens 5 of the support 2.

In normal operation of the pendulum damping device 1 shown in FIG. 1, the rollers 6 are in contact both with the internal raceways 7 and with the external raceways 8. When the speed of rotation of the pendulum device 1 is typically less than 200 rpm, the rollers 6 are less and less pinched between the internal and external rolling tracks 7, 8, and when stopped, when the pendular masses 3 no longer oscillate, certain rollers 6 fall on the internal tracks 7 (configuration not shown), which generates unwanted noise.

The general principle of the invention is to press the rolling members 6 against the pendulum masses 3 or the support 2, in variants of the device different from that shown.

To do this, in the first embodiment of the invention, the pendulum masses 3 each include a magnet 9 as shown in the sectional view of Figure 2, in order to exert an axial magnetic attraction on the metal rollers 6 .

In the example shown, the magnet 9 is a magnetic pad, preferably made of ferrite.

This patch 9 is arranged in a countersink of each of the pendulum masses 3 and has a sufficient size so as to remain, at least in part, opposite each of the rollers 6 during the movement of the pendulum body 3, 6.

The magnet 9 is protected by a plastic shoe 10 interposed between the pendulum mass 3 and the support 2 and the roller 6. This shoe 10 prevents a concentration of metallic particles between the pendulum mass 3 and the roller 6 or the support 2 , which would be detrimental to the operation of the pendulum device 1.

Due to the existing games, the roller 6 is placed in an asymmetrical position relative to the support 2 between the pendulum masses 3, as illustrated in Figure 2: only one of the opposite axial faces 11, 12 is in contact with one either of the pendulum masses 3.

The magnetic pad 9 has a sufficient residual magnetic flux density to attract the roller 6 as a function of the thickness of the pad 10, when the roller is in the middle position between the pendulum masses 3.

Only one of the pendulum masses 3 is, as a variant, provided with a magnet 9, provided that its residual magnetic flux density is sufficient to attract the roller 6, as a function of the thickness of the pad 10, when the roller is in another position close to the opposite pendular mass 3.

According to the general principle of the invention, there is creation of a plating force which, combined with the coefficient of friction between the shoe 10 and the roller 6, creates a hysteresis between the roller 6 and the pendulum mass 3. From the so, the roller 6 is no longer free to move under its own weight when the speed of rotation decreases.

In the pendulum device 1 according to the invention in the first embodiment shown in Figure 1, the rolling members 6 are in one piece and made of a magnetic metal.

However, in this situation, any metallic particle, such as the filings formed by the wear of the metallic parts, risks being attracted by the magnetized roller 6 by being subjected to the magnetic attraction of the magnet 9, and becoming place in a functional area of the pendulum device 1, and therefore risk of degrading its filtering function.

In order to overcome this drawback, sharp edges 13 capable of locally creating a concentration of the magnetic flux are placed outside the functional areas.

As FIGS. 4a and 4b clearly show, each of the opposite axial faces 11, 12 of a roller 14 comprises, in the particular variant of the first embodiment:

- a flat central zone 15 of plating;

- A peripheral groove 16 provided with an external flange 17 having a sharp edge 13;

- softer evolutionary zones 18 near the rolling zones 19.

A radius of this sharp edge 13 is advantageously less than 0.3 mm.

The metallic particles attracted by the sharp edge 13 by being collected in the annular groove 16 do not disturb the operation of the pendulum device 1, neither at the level of the contact of the roller 14 with the support 2 or the spacer 4, nor at the level of the contact with the pendulum mass 3, as will be readily understood from the section of the pendulum device 1 in FIG. 5, in this particular variant of the first embodiment.

In a second embodiment of the pendulum device 1 according to the invention, the drawback of the attraction of magnetic particles by a magnetized metallic roller 6 is avoided by a composite structure.

Rolling members 6 formed of ceramic around a metal axial ball (not shown) do not in fact comprise a metal part close to the rolling zone 19.

In another embodiment of the pendulum device 20, 21 according to the invention, the pendulum masses 3, or the support 2, comprise magnets 9 arranged in blind guide grooves 22, 26 of the ends of rolling members 23 having axial shoulders 24 as clearly shown in the sectional views of FIGS. 6 and 7.

In the example shown in Figure 6, as in the previous examples, the pendulum masses 3 of the pendulum device 20 are arranged on either side of the support 2. One of the magnets 9 secured to one of the pendulum masses 3 in one of the grooves 22 creates a magnetic attraction which presses one of the axial shoulders 24 against one of the pendulum masses 3. The axial shoulders thus define the cladding zones. The edges of the grooves define the internal raceways 7.

In the other example shown in Figure 7, unlike the previous examples, the pendulum masses 3 of the pendulum device 21 are arranged between two flanges 25 of the support 2. These flanges have other blind grooves 26 in which are arranged the magnets 9. The magnetic attraction created by one of these magnets 9 secured to the support 2 then plates one of the axial shoulders 24 of one of the rolling members 23 against one of the flanges

25. The edges of the grooves 26 of the flanges 25 define the external raceways 8.

It goes without saying that the invention is not limited to the preferential embodiments described above.

In particular, the type of magnet 9 in pellets corresponds only to an exemplary embodiment of the invention.

Other types of magnets 9, in one or more copies, different or not, can be advantageously used such as flat magnets of square or rectangular shape, or even adapted to the profiles of the paths of the rolling elements 6, 14, 23 during their movements.

The invention embraces, on the contrary, all the possible variant embodiments within the limits of the subject of the claims below.

Claims (10)

1) Pendulum damping device (1, 20, 21) for the transmission of a motor vehicle of the type comprising: - a support (2) driven in rotation about an axis (XX ') of said transmission; - at least one pendulum body (3, 6, 14, 23) comprising at least one pendulum mass (3) and rolling members (6, 14, 23), said pendulum body (3, 6, 14, 23) being movable relative to said support (2), said rolling members (6, 14, 23) cooperating with: - Internal raceways (7) integral with said pendulum mass (3) and associated with said rolling bodies (6, 14, 23); - external raceways (8) integral with said support (2) and associated with said rolling bodies (6, 14, 23); characterized in that said pendulum mass (3) or said support (2) comprises at least one magnet (9) facing said rolling members (6, 14, 23) during said movement. 2) pendulum damping device (1, 20, 21) according to claim 1, characterized in that, under a magnetic attraction generated by said magnet (9), one of the opposite axial faces (11, 12) of each of said rolling members (6, 14, 23) exclusively is in contact at least in part with said pendulum mass (3) or said support (2). 3) pendulum damping device (1) according to claim 2 above, characterized in that said pendulum mass (3) comprises a countersink comprising said magnet (9) and further comprises a shoe (10) interposed between said magnet (9 ) and said rolling members (6, 14). 4) pendulum damping device (1) according to claim 3, characterized in that said shoe (10) is made of plastic. 5) pendulum damping device (1) according to any one of the preceding claims 2 to 4, characterized in that said rolling members (6, 14) are in one piece and made of a magnetic metal. 6) pendulum damping device (1) according to claim 5, characterized in that said opposite axial faces (11, 12) each have a peripheral groove (16) provided with an external flange (17) having a sharp edge (13). 7) pendulum damping device (1) according to claim 6, characterized in that a radius of said sharp edge (13) is less than 0.3 mm. 8) pendulum damping device (1, 20, 21) according to any one of the preceding claims 1 to 4, characterized in that the said rolling members (6, 14, 23) are composite with a central core consisting of a magnetic metal. 9) pendulum damping device (1, 20, 21) according to claim 8, characterized in that said rolling members (6, 14, 23) are formed of ceramic around a metal axial ball. 10) pendulum damping device (1, 20, 21) according to any one of the preceding claims 1 to 9, characterized in that said magnet (9) is formed from a magnetic pad, preferably made of ferrite.