Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D7/00—Steering linkage; Stub axles or their mountings
  • B62D7/22—Arrangements for reducing or eliminating reaction, e.g. vibration, from parts, e.g. wheels, of the steering system
  • B62D7/228—Arrangements for reducing or eliminating reaction, e.g. vibration, from parts, e.g. wheels, of the steering system acting between the steering gear and the road wheels, e.g. on tie-rod
• • 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
  • F16F1/00—Springs
  • F16F1/36—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers
  • F16F1/38—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers with a sleeve of elastic material between a rigid outer sleeve and a rigid inner sleeve or pin, i.e. bushing-type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D3/00—Steering gears
  • B62D3/02—Steering gears mechanical
  • B62D3/12—Steering gears mechanical of rack-and-pinion 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
  • F16F2230/00—Purpose; Design features
  • F16F2230/10—Enclosure elements, e.g. for protection
  • F16F2230/105—Flexible, e.g. bellows or bladder

Definitions

• the present invention relates to steering mechanisms for vehicles, and more particularly to the arrangement of steering rods which are used in such mechanisms to transmit a steering movement of the steering rack to the stub axles which carry the steering wheels.
• a suitably sized damping member could advantageously make it possible to create, when the driver maneuvers the steering wheel, a phase shift (a delay) between the steering wheel orientation angle and the angle of the steering wheel, phase shift which has the effect of increasing the turning radius of the vehicle, compared to what would be said turning radius if the wheels followed exactly and instantly the steering wheel angle, and so reduce the yaw rate of the vehicle, so that the vehicle is less likely to survive.
• damping members tends to increase the size and weight of the steering mechanism, and exposes said mechanism to an increased risk of corrosion, to the extent that water or salt spray (that is, droplets of salt water which are suspended in the air, either naturally because the vehicle is at the seaside, or for example after salting the roadway from the roadway) can sometimes infiltrate between the metal parts that house said damping members.
• water or salt spray that is, droplets of salt water which are suspended in the air, either naturally because the vehicle is at the seaside, or for example after salting the roadway from the roadway
• the objects assigned to the invention are therefore intended to overcome the aforementioned drawbacks, and to propose a new steering mechanism arrangement which provides effective mechanical filtering of shocks and vibrations caused by the unevenness of the roadway, as well as an improvement in the behavior vehicle dynamics, including lace, while maintaining a certain compactness and good resistance to corrosion.
• a steering mechanism comprising a steering rack which is slidably mounted in a steering gear, said gear rack having an end which emerges from said steering gear and which is connected to a steering link, said steering link having a stem which connects a first articulation member, such as a ball sphere, connected to the rack, to a second articulation member for connecting said steering rod to an effector member, such as a knuckle, said mechanism also comprising an elastic sealing sleeve which joins the steering gear to the steering rod so as to delimit a protective enclosure, at least liquid watertight, around the end of the rack, said mechanism being characterized in that the rod of the steering rod is subdivided into a portion of upstream rod, carrying the first articulation member, and a downstream rod portion distinct from the upstream rod portion and carrying the second articulation member.
• upstream rod portion is connected to the downstream rod portion by a junction which comprises an elastic damping member which is interposed between the upstream rod portion and the downstream rod portion so as to damp relative movements.
• the downstream rod portion relative to the upstream rod portion, and in that said junction is located inside the protective enclosure defined by the sealing sleeve.
• the elastic damping member interposed between the upstream rod portion and the downstream rod portion allows a certain relative mobility of the downstream rod portion relative to the upstream rod portion, and in particular axial relative movements of va-and -sili, while dissipating the energy of said relative movements, which allows, in particular, according to a first function, to dampen shocks and vibrations from the road, and thus prevent said shocks and vibrations up to driving wheel, or even, according to a second function, to create a controlled phase shift between the operation of the steering wheel and the response in actual orientation of the steering wheels, so as to reduce the yaw rate, and thus make the behavior of the steering wheel vehicle turns more progressive.
• the fact of placing the junction between the upstream and downstream rod portions in the same protective enclosure as the open end of the steering gear and the end of the rack, under the shelter under the sealing sleeve makes it possible to preserve said junction from any penetration of at least liquid water, and in particular of salt spray, or of dust, grit or fluids present on board the vehicle, such as fuel, lubricant, brake fluid, etc.
• the fact of placing the junction, and more particularly the damping member, as well as the sealing sleeve (steering bellows) which protects said junction, in a volume of space which is already occupied usually by said sleeve sealing, does not increase, or at least not significantly increase the size of the steering mechanism.
• FIG. 1 illustrates, in a partial perspective view, a steering mechanism according to the invention, on which the sealing sleeve has been removed to reveal the end of the rack and the junction between the upstream rod portions. and downstream.
• Figure 2 illustrates, in a perspective view, the steering mechanism of Figure 1 with the sealing sleeve in place.
• FIG. 3 illustrates, in a detail view in longitudinal section, the protective enclosure of the steering mechanism of FIGS. 1 and 2.
• Figure 4 illustrates, in a perspective view cut longitudinally, the detail of a steering rod of the mechanism of Figures 1 to 3.
• FIG. 5 illustrates, in an exploded view in longitudinal section, the steering rod of FIG. 4.
• FIG. 6 illustrates, in a diagrammatic cross-sectional view, the crimping operation that makes it possible to fasten two constituent elements of the upstream rod portion by plastic deformation.
• the present invention relates to a steering mechanism 1 comprising a steering rack 2 which is slidably mounted in a steering box 3.
• Said rack 2 has an end 2A which emerges from said steering casing 3 and which is connected to a steering rod 4.
• Said steering link 4 comprises a rod 5 which connects a first articulation member 6, such as a ball sphere 6, connected to the rack 2, to a second articulation member 7 intended to connect said steering rod 4 an effector 8, such as a knuckle 8.
• Said rocket door 8 carries at least one steering wheel 9, as shown schematically in Figure 2, so that when the rack 2 is moved, it causes the rod 4 which acts in turn on the knuckle 8 to change the yaw orientation of said wheel 9.
• the steering mechanism 1 belongs to a power steering system equipped with an assistance motor 10, preferably an electric assistance motor, for example of the type brushless, said assistance motor 10 being intended to produce an assist force which helps the driver to maneuver the steering mechanism 1, according to predetermined assistance laws which are stored in a computer that manages said steering system.
• an assistance motor 10 preferably an electric assistance motor, for example of the type brushless, said assistance motor 10 being intended to produce an assist force which helps the driver to maneuver the steering mechanism 1, according to predetermined assistance laws which are stored in a computer that manages said steering system.
• the steering mechanism 1 will also comprise, in a manner known per se, a steering wheel 11 which allows the driver to actuate said mechanism 1.
• said steering wheel 11 is for this purpose carried by a steering column 12 which engages on the rack 2 by means of a drive pinion 13.
• the steering mechanism 1 also comprises a resilient sealing sleeve 14 which joins (axially) the steering casing 3 to the steering link 4 so as to delimit a protective enclosure 15, at least liquid watertight, around the end 2A of the rack 2, and more particularly around the first hinge member 6.
• the tightness of the protective enclosure 15 will advantageously prevent any intrusion of liquid water into said protective enclosure 15, and in particular any intrusion of runoff water from the rain or projected by the wheels, or else any intrusion of salt spray.
• the protective enclosure 15 will be at least liquid watertight, and this over a pressure range that extends at least from atmospheric pressure to a pressure of 100 bar or more, in order to support high pressure cleaning.
• the protective enclosure 15 will be even more tightly impervious to solid particles, like gravel, as well as liquids other than water, likely to be in the external environment of the steering mechanism 1, and which it is desired that they can not enter the protective enclosure 15, such as for example automotive liquids lubricant type (oil), fuel, coolant, brake fluid, etc.
• said sealing sleeve 14 is made of elastomeric material.
• the sealing sleeve 14 is formed by a bellows, preferably an elastomer, and can therefore be likened to a bellows in what follows.
• Such a bellows shape will facilitate in particular the elastic deformations in axial compression, in axial extension, and in angular deflection (in flexion) of the sealing sleeve 14, which allow said sealing sleeve 14 to accommodate the relative displacements in approach and away from the end 2A of the rack and the rod 4 relative to the steering housing 3, and whatever the angular orientation of said link 4 with respect to the rack 2 and the steering housing 3.
• the rod 5 of the steering rod 4 is subdivided into an upstream rod portion 5A, carrying the first articulation member 6, and a downstream rod portion 5B distinct from the upstream rod portion 5A and bearing the second articulation member 7.
• the upstream rod portion 5A is connected to the downstream rod portion 5B by a junction 16 which comprises an elastic damping member 17 which is interposed between the upstream rod portion 5A and the downstream rod portion 5B so as to dampen displacements relative to the downstream rod portion 5B with respect to the upstream rod portion 5A (and vice versa).
• the elastic damping member 17 will be arranged so as to damp, by its elastic deformation, the relative axial displacements of the upstream rod portion 5A with respect to the downstream rod portion 5B.
• Said relative displacements may result for example axial forces traction or compression exerted by the rack 2, and in particular by the steering wheel 11, during steering maneuvers, against the steering wheel 9, or even result tensile or compressive forces which correspond to impacts or vibrations caused by the action of the roadway on the steering wheel 9.
• upstream an element facing the rack 2, the casing 3, and the driving wheel 11, and “downstream” an opposite element, to the stub axle 8 and the steering wheel 9.
• the stiffness of the damping member 17 is advantageously chosen lower than the Young's modules of the upstream rod portions 5A and 5B downstream, so as to allow on the one hand an elastic relative mobility, in particular axial, between said upstream rod portions 5A and downstream 5B, by elastic deformation of said damping member 17 in tension / compression, and on the other hand a damping of the axial oscillations in tension / compression.
• the subdivision of the rod into an upstream portion 5A and a downstream portion 5B, and therefore the junction 16 comprising the damping member 17, is, as is particularly visible in Figures 1, 3 and 4, distinct articulation members 6, 7, and located outside the articulation members 6, 7, at a distance from these.
• said junction is considered distinct from and located outside the cages of the ball joints which connect the rod 5 respectively to the rack 2 and to the knuckle 8.
• the junction 16 is located inside the protective enclosure 15 delimited by the sealing sleeve 14, as can be seen in Figures 1, 2 and 3.
• the sealing sleeve 14 thus forms an envelope which extends from the casing 3 on the one hand, to which the said sealing sleeve 14 is sealingly attached at least to the liquid water, for example by means of a first constriction flange 20 of the elastic ring type, downstream of the junction 16 on the other hand, and more particularly downstream of the apparent separation line 21 of said junction 16.
• dividing line 21 denotes the zone where the physical separation appears between the upstream rod portion 5A and the downstream rod portion 5B.
• said separation line 21 can thus be embodied by a visible portion of the damping member 17 sandwiched between the upstream rod portion 5A and the downstream rod portion 5B, as illustrated in FIGS. 4.
• a second constriction flange 22, of the spring ring type, makes it possible to tighten the sealing sleeve 14 at least in liquid-tight manner against the rod 5 of the connecting rod 4, all around the longitudinal axis X4, such as that this is visible in Figures 2 and 3.
• the casing formed by the sealing sleeve 14 thus covers not only the end 2A of the rack, as well as a portion of the steering rod 4 including the first articulation member 6, but also the junction 16 , and more particularly the separation line 21, and thus keeps all these elements in the shelter in the same sealed enclosure which extends from the housing 3 to (at least) the downstream rod portion 5B of the link 4.
• the sealing sleeve 14 thus effectively protects (at least) moisture and water splashes the junction 16, and more particularly the interface formed by the damping member 17 between the upstream rod portion 5A and the portion 5B downstream rod at the separation line 21, without the need to provide specific sealing members at said line of separation 21.
• the downstream rod portion 5B is provided with a receiving housing 23, intended to receive the damping member 17 and a portion 24 of the upstream stem portion 5A, called "foot" 24, on which said damping member 17 bears.
• said receiving housing 23 is formed by a blind hole which is pierced axially in the downstream rod portion 5B. , which is delimited radially by a side wall 23L, and which has a passage opening 25 allowing the introduction of the damping member 17 and the foot 24 of the upstream rod portion 5A into said receiving housing 23.
• the downstream rod portion 5B has for this purpose a bulge 26 terminal, preferably cylindrical and centered on the longitudinal axis X4, which is hollowed to form the receiving housing 23. Said bulge 26 thus forms a kind of junction box.
• the side wall 23L is advantageously full, all around the longitudinal axis X4, and therefore watertight, so that the only access to the receiving housing 23, and therefore the only area potentially vulnerable to intrusion of water, ie the passage opening 25.
• the sealing sleeve 14 can then engage the radially outer surface of the side wall 23L of the receiving housing 23, while the passage opening 25 of said receiving housing opens upstream, so as to be located inside the protective enclosure 15.
• the separation line 21, which is in this case annular and centered on the longitudinal axis X4, is entirely contained in the protective enclosure 15, inside the sealing sleeve 14, between firstly a first upstream end 14A of said sealing sleeve which is sealingly connected to the housing 3, and secondly a second downstream end 14B of said sealing sleeve which is sealingly connected to the bulge 26 of the portion of downstream rod 5B, downstream of the separation line 21, and which is thus closed by said downstream rod portion 5B.
• the fact of orienting upstream the passage opening 25 thus makes it possible easily and effectively to protect, inside the sealing sleeve 14, the junction 16, and more particularly the separation line 21, and therefore access to the housing 23 and the damping member 17, without the risk of seeing the sealing sleeve 14 accidentally discover, in particular due to slippage or wear, said separation line 21.
• sealing sleeve 14 engages the full side wall 23 of the housing 23, by annular clamping of its downstream end 14B on the bulge 26, that is to say comes into taken on an enlarged diameter of the downstream rod portion 5B, advantageously provides a solid grip of said sealing sleeve 14 on said downstream rod portion 5B.
• downstream rod portion 5B preferably forms a female portion of the junction 16 while the upstream rod portion 5A forms the conjugate male portion of said junction 16, is particularly suitable for masking the junction 16 by the sealing sleeve 14, since it makes it possible to orient upstream the passage opening 25 and the separation line 21, according to a variant that will be called " variant with upstream junction ".
• downstream junction variant a reverse arrangement, with a portion of upstream rod 5A female receiving a portion of downstream rod 5B male, without departing from the scope of the invention.
• upstream rod portion 5A connected to the rack 2, which would form the female part of the junction 16, carrying the housing 23 and, where appropriate, the terminal bulge 26, while the 5B downstream rod portion, connected to the knuckle 8, would form the male part (the foot 24), so that the junction 16, and more particularly the separation line 21 and the passage opening 25, would be oriented towards the downstream (rather than upstream as in Figure 3), downstream of the bulge 26.
• the sealing sleeve 14 would be extended downstream, so as to engage on the downstream portion of the rod 5B beyond the bulge 26 and beyond junction 16 (in the downstream direction).
• each of the variants ensures the protection of the junction 16, since it is always well and truly surrounded by the sealing sleeve 14, which axially overlaps said junction 16 so as to extend axially on either side of the latter (and more particularly on either side of the separation line 21), both upstream and downstream.
• upstream junction variant which allows a more compact embodiment, with a sleeve 14 shorter, and offers better resistance to wear and abrasion.
• damping member 17 may take any suitable form.
• the damping member 17 could be formed by a hydraulic or pneumatic damper, and / or comprise, or even be formed by, a metal spring, such as a coil spring, in charge of accommodating elastically, on a beach predetermined displacement, the relative displacements of the upstream rod portion 5A relative to the downstream rod portion 5B.
• a metal spring such as a coil spring
• the damping member 17 is elastomeric, and particularly preferably formed of a single piece of elastomeric material, for example by overmolding.
• the choice of an elastomer block advantageously and cheaply provides the required elastic deformability and damping properties.
• the foot 24 of the upstream rod portion 5A is surrounded by a fixing sleeve 30, preferably metal, which fits into the housing d 23 of the downstream rod portion 5B.
• the damping member 17 may then advantageously be formed by an elastomeric damping sleeve which is overmolded around the foot 24, so as to fill a filling space 31 provided for this purpose, in particular radially, between said foot 24 and said fixing sleeve. 30.
• the damping member 17 is thus on the one hand interposed, here at least radially, between the foot 24 and the fixing sleeve 30, and of on the other hand maintained in one piece between the foot 24 and the fixing sleeve 30, not only radially, but also axially to ensure its function of axial damper.
• the fixing sleeve 30 is in turn preferably fixed by crimping in the receiving housing 23, preferably by plastically folding an annular flange 32 of the side wall 23L of the receiving housing 23 over a flange 33 of said bushing 30, as shown in Figure 3.
• such an assembly by interlocking and crimping is particularly simple and inexpensive to implement.
• the crimping takes place substantially on the perimeter of the passage opening 25, substantially along the separation line 21, so that the crimped zone is contained in the protective enclosure, and by therefore protected from water, dust, and corrosion, in particular without the need for an additional seal or a special treatment of the metal constituting the fixing sleeve 30.
• Said collar 43 advantageously abuts axially, preferably via the damping member 17, on the one hand against the bottom 23F of the receiving housing 23, when the rod 5 is biased in axial compression (that is, that is, when the upstream rod portion 5A of the downstream rod portion 5B is brought into axial compression against the damping member 17) and against a ring 30B of the fixing sleeve 30, here a downstream song 30B of said bushing, when the rod 5 is biased in axial traction (that is to say in the opposite direction to the previous one, when axially moving the upstream rod portion 5A away from the rod portion downstream 5B, against the damping member 17).
• JA is noted the predetermined axial clearance which defines, between the foot 24 and the bushing 30, and more particularly between the collar 43 and the downstream edge 30B of the sleeve 30, the permissible axial displacement range in tension.
• the damping sleeve (damping member) 17 has a mushroom shape comprising a head 40 which abuts (at least axially) against the bottom 23F of the receiving housing 23, opposite the passage opening. 25, as well as a first stop flange 41, which forms a first shoulder against which the downstream edge 30B of the fixing bushing 30 bears (axially), and which is separated from the head 40 by the axial clearance JA predetermined above.
• the foot 24 of the upstream rod portion 5A will elastically compress, and without shock, the downstream portion of the head 40 of the damping member 17 against the bottom 23F of the housing 23, while when axial traction is exerted on the rod 5, the foot 24 will elastically compress the upstream portion of the head 40 of the damping member 17 against the sleeve 30, and more particularly against the first stop collar 41, which is interposed between the collar 23 and the downstream edge 30B of said sleeve 30.
• a clearance zone 44 for example conical, allowing the constituent material of the organ damper 17 to flow freely when it is driven by the foot 24 of the upstream rod portion 5A which presses said damping member against the bottom 23F.
• the head 40 of the damping member 17 preferably has a radially projecting shoulder shape, which corresponds to the coating by the elastomeric material of the collar 43 of the foot 24.
• a radially projecting shoulder shape corresponds to the coating by the elastomeric material of the collar 43 of the foot 24.
• Such a shape ensures on the one hand a good axial anchoring of the elastomeric material constituting the damping member 17 on the upstream rod portion 5A, and on the other hand a precise adjustment of the axial clearance JA, the collar 43 being placed axially in position. vis-à-vis the first flange 41 and the corresponding downstream edge 30B of the fixing sleeve 30.
• the second flange 42 of the damping member 17 will thus preferably be located at the passage opening 25 to form the visible portion of the damping member 17, which marks the dividing line 21 between the upstream rod portion 5A and the downstream rod portion 5B.
• first and second stop flanges 41, 42 may contribute to reinforcing the axial anchoring of the damping member 17 on the fixing bushing 30, and therefore more generally the axial anchorage (elastic) of said fastening bushing 30 on the upstream portion of the rod 5A.
• the upstream rod portion 5A is formed by the meeting on the one hand of a tip 50, which comprises the first articulation member 6 as well as a threaded shank 51 and on the other hand a foot 24 intended to bear against, and preferably inside, the damping member 17 and which has a hole 52, here smooth, in which the threaded tail 51 is engaged then immobilized by plastic deformation in a press 54, 55 of said hole 52, as shown in FIG. 6.
• said matrices 54, 55 will have a substantially hexagonal section so as to create a resulting hexagonal profile at the apparent surface of the foot 24. It will be noted that in order to manufacture the link rod 5 according to the invention, it will therefore be advantageous:
• the invention also relates as such to a vehicle, and more particularly to a motor vehicle, equipped with a steering mechanism 1 according to the invention.
• the present invention is furthermore not limited to the variants described above, the person skilled in the art being able in particular to isolate or freely combine one or the other of the aforementioned characteristics, or to substitute an equivalent .

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)
• Sealing Devices (AREA)
• Vibration Prevention Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=57590655

Family Applications (1)

Country Status (7)

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Citations (2)

Family Cites Families (22)

• 2016
  • 2016-10-11 FR FR1659804A patent/FR3057232B1/fr not_active Expired - Fee Related
• 2017
  • 2017-10-09 US US16/333,425 patent/US10953917B2/en not_active Expired - Fee Related
  • 2017-10-09 WO PCT/FR2017/052760 patent/WO2018069616A1/fr not_active Ceased
  • 2017-10-09 BR BR112019006387A patent/BR112019006387A2/pt not_active IP Right Cessation
  • 2017-10-09 EP EP17793706.7A patent/EP3526104A1/de not_active Withdrawn
  • 2017-10-09 CN CN201780062472.1A patent/CN109982915A/zh active Pending
  • 2017-10-09 JP JP2019540708A patent/JP2019536693A/ja active Pending

Patent Citations (2)

Non-Patent Citations (1)

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