Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
  • F16F9/10—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using liquid only; using a fluid of which the nature is immaterial
  • F16F9/14—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect
  • F16F9/16—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts
  • F16F9/18—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts with a closed cylinder and a piston separating two or more working spaces therein
  • F16F9/19—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts with a closed cylinder and a piston separating two or more working spaces therein with a single cylinder and of single-tube type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
  • F16F9/32—Details
  • F16F9/3207—Constructional features
  • F16F9/3221—Constructional features of piston rods
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
  • F16F9/32—Details
  • F16F9/3207—Constructional features
  • F16F9/3235—Constructional features of cylinders
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
  • F16F9/32—Details
  • F16F9/36—Special sealings, including sealings or guides for piston-rods
  • F16F9/366—Special sealings, including sealings or guides for piston-rods functioning as guide only, e.g. bushings
  • F16F9/367—Special sealings, including sealings or guides for piston-rods functioning as guide only, e.g. bushings allowing misalignment of the piston rod

Definitions

• the present invention relates to a shock absorber for a motor vehicle comprising a Mac Pherson type suspension, the shock absorber comprising a body and a rod sliding in the body.
• FIG. 1 represents such a suspension. It is known that this type of suspension comprises a strut 10 consisting essentially of a shock absorber 11 participating at the same time in guiding the wheel.
• the shock absorber 11 comprises a body 12 and a rod 14.
• the shock absorber has a shock absorber axis "X1".
• the body 12 comprises a cylindrical bore 15 delimited by an internal cylindrical wall and the main axis of which is coaxial with the axis "X1" of the damper.
• the bore 15 opens out through an upper axial opening 17.
• the rod 14 has a main axis which extends coaxially with the axis "X1" of the damper. It is mounted to slide coaxially in the bore 15 of the body through the opening 17, as shown in Figure 2.
• the upper end 16 of the rod 14 rests on the body 19 of the vehicle at an articulation point 18 generally materialized by an elastic articulation.
• a helical spring 20 is mounted between an upper cup 22 and a lower cup 24.
• the lower cup 24 bears on the body 12 of the shock absorber 11 and the upper cup 22 bears on the body 19 of the vehicle, either directly or through articulation 18.
• the body 12 is made integral with a hub carrier 26. There is therefore no degree of freedom between the body 12 and the hub carrier 26.
• a lower arm 28 is articulated on one side on the body 19 of the vehicle and on the other on the hub carrier 26 by an articulation 30.
• the hub carrier 26 supports a hub 32, on which is mounted a wheel 34 fitted with its tire 36.
• the strut 10 occupies a vertical position which also does not allow the thrust "P" of the spring 20 to pass close enough to the point "C” to contain the shear force "T” in. the optimum operating range.
• the spring 20 must be arranged coaxially with the rod 14 of the damper 11, for example to allow a component (not shown) to be interposed between the spring 20 and the damper 11. In in this case too, this arrangement does not allow the thrust "P" of the spring 20 to pass in sufficient proximity to the point "C” to contain the shear force "T” in the optimum operating range.
• the intensity of the shearing force “T” applied to the upper end 16 of the rod 14 of the damper 11 becomes greater than the first determined threshold “S1”.
• the rod 14 is slidably guided in the bore 15 of the body 12 by a guide ring 38 which is fixed in the upper opening 17 of the body 12, on the one hand, and by a piston 40 which is fixed at one end lower of the rod 14.
• the shearing force "T” causes a torque which tends to offset the rod 14 relative to the body 12. This results in the support of an intermediate portion of the rod 14 on the ring 38 of guide which, by leverage, causes the piston 40 to be pressed in an opposite direction on the body 12 of the shock absorber 11.
• the reaction force "R1" of the guide ring 38 on the rod 14 and the reaction force "R2" of the body 12 on the piston 40 have been shown in Figure 2.
• reaction forces "R1", “R2” are oriented radially with respect to the axis of the rod 14, thus causing a very significant friction at the points of contact between the rod 14 and the guide ring 38, on the one hand. , and between the piston 40 and the body 12, on the other hand.
• the friction is high enough to cause premature wear of the damper 11, or even seizure of the sliding of the rod 14 in the body.
• the invention relates to a shock absorber for a motor vehicle suspension, in particular for a Mac Pherson type suspension, having a main axis and comprising:
• a body made of ferromagnetic material comprising a cylindrical bore coaxial with the damper axis and opening through an axial opening;
• a rod which is made at least in part from a ferromagnetic material and which is mounted to slide coaxially in the bore through the opening;
• a piston which is fixed to a free end of the rod and which is slidably received in the bore; characterized in that it comprises at least a first permanent magnet which is fixed in the bore radially at a distance from the rod and which is arranged close to the guide ring, the first magnet exerting an attractive force on the rod in a first determined radial direction.
• the damper comprises at least one second permanent magnet which is fixed to the rod at a radial distance from the internal wall of the bore and which is arranged near the piston, the second magnet attracting the rod towards the body with a force d attraction directed in a second radial direction opposite to the first determined radial direction;
• a ring made of a non-magnetic material, such as plastic
• the magnet forms an angular sector of the ring, a complementary sector being made of plastic material, for example by overmolding;
• the first magnet and the second magnet are arranged radially in opposition to the axis of the shock absorber and they are offset axially along the axis of the shock absorber.
• the invention also relates to a motor vehicle running gear comprising:
• a strut comprising a shock absorber comprising a rod, an upper end of which bears on a body of the vehicle and a body which is integral with the hub carrier of the vehicle, the body exerting on the upper end of the rod a directed shearing force radially with respect to the shock absorber axis,
• the damper is produced according to any one of the preceding claims, the force of attraction exerted by the first magnet on the rod being opposite to said shearing force.
• the running gear comprises a lower arm which is articulated on one side on the body of the vehicle and on the other on the hub carrier, the arm exerting on the hub carrier a force of determined guidance, the reaction of the vehicle body on the strut being directed towards a point defined by the intersection of the force exerted by the lower arm on the hub carrier and the resultant of the forces that the ground exerts on the tire, the thrust exerted by the spring being directed in a direction passing away from said point of intersection.
• FIG. 1 is a front view which schematically represents a motor vehicle running gear equipped with a strut produced according to the state of the art
• Figure 2 is an axial sectional view which shows a shock absorber equipping the strut of Figure 1 produced according to the state of the art;
• FIG. 3 is an axial sectional view which represents a damper produced according to the teachings of the invention.
• Figure 4 is a perspective view which shows a ring equipped with a permanent magnet which is arranged in the damper of Figure 3.
• strut 42 similar to that which has been described with reference to Figures 1 and 2 which comprises a suspension spring 20 and a shock absorber 11.
• This strut 42 is arranged in the vehicle so identical to what has been described for the strut 10 of the prior art with reference to FIG. 1. Thereafter only the differences between the strut 42 produced according to the teachings of the invention and the leg 10 force produced according to the state of the art will be described.
• the suspension spring 20 of the strut 42 is here arranged so that the thrust "P" of the spring 20 passes a greater distance from the point "C” with respect to the thrust of the spring 20 arranged according to the state. of the technique shown in Figure 1.
• the thrust "P” of the spring of the strut 42 of Figure 3 here cuts the force "B” exerted by the arm 28 on the door - hub 26 at a distance greater than the thrust "P” of the spring of the strut
• the invention provides a shock absorber 11 whose body 12 is made of a ferromagnetic material, and whose rod 14 is made, at least in part, made of ferromagnetic material.
• the damper 11 comprises at least a first permanent magnet 44 which is fixed to the body 12 radially at a distance from the rod 14.
• the first magnet 44 is here arranged near the guide ring 38.
• the first magnet 44 is for example fixed in the bore 15.
• the first magnet 44 thus exerts on the rod 14 a force "F1" of attraction in a first determined radial direction.
• the force "F1” of attraction is more particularly oriented in the same direction as the reaction force "R1" of the guide ring 38 on the rod 14.
• the force "F1" of attraction exerted by the first magnet 44 on the rod 14 is opposed to the shearing force "T".
• the force "F1” exerted by the first magnet 44 on the rod 14 makes it possible to reduce the reaction force "R1" of the guide ring 38 on the rod 14, thus very significantly reducing the friction opposing the sliding of the rod 14 relative to the guide ring 38.
• a part of this reaction force caused by the shearing force '"T" at the level of the guide ring 38 is thus transmitted directly to the body 12 of the damper 11 via the first magnet 44 without causing friction.
• the invention proposes to equip the damper 11 with at least one second permanent magnet 46 which is fixed on the rod 14 at a radial distance from the internal cylindrical wall of the bore 15.
• the second magnet 46 is advantageously arranged near the piston 40.
• the second magnet 46 is thus attracted by the body 12 with a force "F2" of attraction in a second radial direction opposite to the first determined radial direction.
• the force "F2" of attraction is more particularly oriented in the same direction as the reaction force "R2" of the body 12 on the piston 40.
• the second magnet 46 being fixed relative to the rod 14, the force “F2” is therefore also exerted on a section of the rod 14 arranged in the immediate vicinity of the piston 40.
• the force "F2" of attraction on the rod 14 is parallel and in the same direction as the shearing force "T".
• the force "F2" of attraction exerted on the rod 14 makes it possible to reduce the reaction force "R2" of the body 12 on the piston 40, thus very appreciably reducing the friction opposing the sliding of the piston 40 with respect to to the body 12.
• a part of this reaction force caused by the shearing force '"T" at the level of the piston 40 is thus transmitted directly to the body 12 of the shock absorber 11 via the second magnet 46 without causing friction .
• first magnet 44 and the second magnet 46 are arranged radially in opposition with respect to the axis "X1" of the shock absorber and they are offset axially along the axis "X1" of the shock absorber 11 to counteract the shock absorber 11. leverage caused by the shear force "T”.
• the two magnets 44, 46 make it possible to very appreciably reduce the frictional forces produced by the shearing force "T” applied to the upper end 16 of the rod 14. Thanks to this arrangement, it is possible to extend the force. optimum operating range of intensity of the shearing force "T” applied to the rod 14 up to a second threshold "S2" greater than the first threshold "S1" determined for a damper known from the state of the art such as the one shown in Figure 2. Thus, the shearing force "T" may be greater than the first operating threshold of the damper rod 14 11.
• Each magnet 44, 46 is for example a permanent magnet made of a material based on neodymium.
• At least one of the two magnets 44, 46 is carried by a ring 48 with a main axis coaxial with the “X1” axis of the damper.
• the ring 48 has a central orifice 52 delimited by an internal cylindrical face 54.
• the ring 48 is delimited radially outwards by an outer cylindrical face 56.
• the ring 48 made in part from a non-magnetic material, such as plastic, as is for example illustrated in FIG. 4.
• the magnet 44, 46 forms for example an angular sector of the ring 48, the complementary sector 50 being produced in plastic material, for example by overmolding.
• Such a magnet having dimensions of about 4 cm high, over an arc of a circle 2 cm long and over a radial thickness of 1 cm makes it possible for example to obtain an attraction force of the order of 250 N .
• each magnet 44, 46 has a polar "X2" axis passing through its north and south magnetic poles.
• the magnet 44, 46 is more particularly oriented so that its polar axis "X2" is arranged radially with respect to the axis "X1" of the damper 11.
• the ring 48 is then arranged around the rod 14 so that the polar axis "X2" of the associated magnet 44, 46 coincides with the direction of the force "F1, F2" defined previously, ie the polar axis "X2" is parallel to the shear force "T”. This advantageously makes it possible to obtain a maximum attraction force “F1, F2”.
• the ring 48 carrying the first magnet 44 has an outer diameter which is substantially equal to the inner diameter of the bore 15, while the diameter of the central orifice 52 is substantially greater than the outer diameter of the rod 14. This thus makes it possible to reserve sufficient radial play between the rod 14 and the ring 48 to allow the sliding of the rod 14.
• the fixing of the ring 48 on the body 12 can be carried out by tight fitting the ring 48 in the bore 15 and / or by gluing or by any other known fixing means.
• indexing means are for example mechanical means, such as an axial groove, made on one of the two parts, cooperating with an axial tongue, made on the other of the two parts.
• the ring 48 carrying the second magnet 46 has an outer diameter which is substantially smaller than the inner diameter of the bore 15, while the diameter of the central orifice 52 is substantially equal to the outer diameter of the rod 14. This thus makes it possible to reserve sufficient radial clearance between the body 12 and the ring 48 to allow the sliding of the rod 14.
• the fixing of the ring 48 on the rod 14 can be achieved by tight fitting the ring 48 around the rod 14 and / or by gluing or by any other known fixing means.
• the piston 40 divides the bore into two chambers.
• the bore is generally filled with a viscous fluid, such as oil, which passes from one chamber to the other through passages of reduced section made in or around the piston 40.
• This viscous fluid thus enables the shock absorber to perform its damping function.
• the complementary sector 50 is advantageously crossed by axial channels (not shown) which facilitate the passage of the oil from one chamber to the other.
• indexing means are for example mechanical means, such as an axial groove, made on one of the two parts, cooperating with an axial tongue, made on the other of the two parts.
• Means are advantageously provided, at least visual, to indicate the angular orientation of mounting of the damper 11 around its axis "X1" so that the magnets 44, 46 act in the correct direction to reduce friction.
• the invention thus makes it possible to easily modify a damper 11 of the state of the art by simply adding two rings 48 each comprising a magnet 44, 46.
• the arrangement of the magnets 44, 46 according to the teachings of the invention makes it possible to substantially increase the range of acceptable values for the shear force "T" applied to the upper end 16 of the rod 14.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Vehicle Body Suspensions (AREA)
• Fluid-Damping Devices (AREA)
• Vibration Prevention Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=67742499

Family Applications (1)

Country Status (3)

Family Cites Families (3)

• 2019
  • 2019-01-18 FR FR1900444A patent/FR3091914B1/fr active Active
• 2020
  • 2020-01-14 WO PCT/EP2020/050802 patent/WO2020148274A1/fr unknown
  • 2020-01-14 EP EP20700227.0A patent/EP3911869A1/de active Pending

Also Published As

Similar Documents

Legal Events