Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R19/00—Wheel guards; Radiator guards, e.g. grilles; Obstruction removers; Fittings damping bouncing force in collisions
  • B60R19/02—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects
  • B60R19/48—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects combined with, or convertible into, other devices or objects, e.g. bumpers combined with road brushes, bumpers convertible into beds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/013—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting collisions, impending collisions or roll-over
  • B60R21/0136—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting collisions, impending collisions or roll-over responsive to actual contact with an obstacle, e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle

Definitions

• the present invention relates to a bumper structure sub-assembly comprising a damping element associated with an impact sensor. It also relates to a bumper structure comprising such a sub-assembly.
• Motor vehicles must thus be able to provide satisfactory responses to impacts occurring at the front bumper of these vehicles while exhibiting different zones and impact forces, such as for example pedestrian impacts and corresponding reparability impacts. at a meeting of a side part of this bumper with a rigid obstacle at a certain speed, often less than 20km / h.
• the cover is made of a material capable of deforming under the effect of this impact.
• Such an impact sensor described in the international application WO 2012/113362 A1, comprises an elastically deformable hollow flexible tube housed in a groove made on the rear face of the damping element, as well as two pressure sensors located at both ends. of this tube and capable of detecting the pressure variations inside the latter caused by the deformation of this damping element during an impact between a body and the front bumper of the vehicle.
• the analysis of the signals transmitted by these sensors allows an electronic control unit to determine the type of collision that has just occurred and thus to control the lifting of the hood in the event of a collision with a pedestrian.
• Such an arrangement makes it possible to prevent the ends of the beam, intended to be positioned opposite the two lateral end portions of the damping element, from coming into direct contact with the tube in the event of a reparability impact. , so as to prevent any shearing of the latter.
• the undamaged impact sensor 40 can thus be reassembled on a new damping element 30, which makes it possible to significantly reduce the amount of repair costs.
• said pressure sensors are also housed inside said cavities;
• said damping element consists of a block of expanded polypropylene foam having a density of between 20 and 80 kg / m 3 ; and or said tube has a circular annular section, the thickness of which is between 0.8 and 1.2 mm.
• the invention also relates in a second aspect to a bumper structure for a motor vehicle comprising a bumper cover, a bumper reinforcement comprising a transverse beam, and such a sub-assembly of which the damping element is implanted longitudinally. between said bumper cover and said beam.
• said damper element extends transversely over a length intermediate those of said covering and of said beam, said groove extending transversely over a length less than that of said beam so that each end of this groove is spaced transversely from the corresponding end of said beam by a predetermined distance
• FIG 3 is an enlarged sectional view of the sub-assembly of Figure 2, taken at an end section of the tube housed in a cavity formed inside a corresponding end portion of the tube. damping element;
• FIG 4 shows an enlarged sectional view of the sub-assembly of Figure 2, taken at the level of a pressure sensor housed in a cavity formed inside a corresponding end portion of the damping element.
• An orthogonal frame XYZ comprising three perpendicular axes two by two, namely:
• a Y axis defining a transverse, horizontal direction, which together with the X axis defines a horizontal XY plane
• a Z axis defining a vertical direction, perpendicular to the horizontal XY plane.
• front and rear will be used to define the relative position of an element with respect to another according to the general direction of movement of the vehicle.
• Figure 1 shows a front bumper structure 1 of a motor vehicle, comprising a bumper cover 10 forming the front end of the vehicle, a bumper reinforcement 20 constituting the front end of the vehicle frame , and a damping element 30 located longitudinally between the bumper cover 10 and the bumper reinforcement 20.
• the bumper trim 10 extends over the entire width of the vehicle while being secured to the body of the vehicle by means of several points of fixing not shown.
• the bumper reinforcement 20 consists essentially of a hollow metal beam 21 extending transversely over a length less than that of the bumper cover 20, and of two identical metal side absorbers 22, each secured to each other. a corresponding side end portion of the beam 21, these absorbers being intended to be fixed to the front ends of the two side sills of the vehicle.
• the beam 21 is designed to transmit to the side absorbers the forces undergone during an impact with the front of the vehicle. It may include internal reinforcing metal plates extending transversely and intended to improve its mechanical strength.
• the two side absorbers 22 are provided, in the event of a reparable impact, to crash and thus absorb the energy of this shock so as to avoid any deterioration of these side stretchers.
• the damping element 30 has a lower mechanical rigidity than that of the bumper reinforcement 20 (and in particular that of its two side absorbers 22).
• this damping element 30 is designed to crash and thus absorb the energy of this impact so as to avoid any deterioration of the bumper reinforcement 20.
• the damping element 30 extends transversely over a length intermediate between that of the bumper cover 10 and that of the beam 21 of the bumper reinforcement 20, from which it extends transversely on both sides.
• the bumper structure 1 also comprises an impact sensor 40 comprising an elastically deformable tube 41, as well as two pressure sensors 42 located at the two ends of this tube 41 and capable of detecting the pressure variations inside. the latter caused by the deformation of this damping element 30 upon impact between a body and the front bumper of the vehicle.
• These two pressure sensors 42 are intended to be electrically connected to an electronic control unit, not shown.
• the analysis of the signals transmitted by the two pressure sensors 42 as well as by other sensors (such as an impact speed sensor) allows this control unit to determine the type of body (for example, a pedestrian or an object such as a post or a low wall) with which the vehicle has just collided.
• control unit In the event of a pedestrian impact being detected, the control unit is thus able to trigger a device for automatically lifting the vehicle hood allowing the latter, in the event of a second impact with the pedestrian's head, to deform sufficiently to ensure efficient absorption of the kinetic energy of this impact.
• the main section 41A of the tube 41 is housed in a groove 31 formed on the rear face 30A of the damping element 30 and extending transversely over a length less than that of the beam 21 of the bumper reinforcement 20 so that each end of this groove 31 is spaced transversely from the corresponding end of the beam 21 by a predetermined distance, advantageously between 10 and 40 mm.
• the groove 31 has a U-shaped section, the semicircular bottom of which is turned towards the rear and the width of which is very slightly greater than the outer diameter of the tube 41.
• the cavities 42 advantageously have a section profile corresponding substantially to that of the sensors, so as to allow, when mounting the impact sensor 40 on the damping element 30, easy insertion by an operator of each of the pressure sensors 42. through the corresponding cavity 42.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Vibration Dampers (AREA)
• Vibration Prevention Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=67107801

Family Applications (1)

Country Status (4)

Families Citing this family (1)

Family Cites Families (9)

• 2019
  • 2019-02-25 FR FR1901863A patent/FR3093046B1/fr active Active
• 2020
  • 2020-02-20 CN CN202080016548.9A patent/CN113474222A/zh active Pending
  • 2020-02-20 EP EP20710259.1A patent/EP3931049A1/de not_active Withdrawn
  • 2020-02-20 WO PCT/FR2020/050318 patent/WO2020174161A1/fr unknown

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