Internal reinforcement element for a tank made of plastic for a motor vehicle

An internal reinforcement element for a plastic tank for a motor vehicle, said internal reinforcement element comprising:

• a central structure comprising
• a first system of ribs, called a primary system of ribs, comprising at least three primary ribs joined to one another, each primary rib being joined to the other primary ribs by a single side, the central structure having a joint of the at least three primary ribs at its center, said joint and said primary ribs extending along an axis,
• a second system of ribs, referred to as a secondary system of ribs, comprising at least two secondary ribs, said at least two secondary ribs being located on both sides of a primary rib and being joined on one side to the primary rib, said at least two secondary ribs extending along an axis parallel to the axis, each secondary rib forming an angle greater than 0° with the primary rib to which it is joined,
• the sides of the primary ribs opposite the joint-forming sides and the sides of the secondary ribs opposite the sides joined to the primary rib defining a projected surface of the central structure having a first peripheral geometric shape along the axis,
• a first end and a second end located on both sides of the central structure, each comprising the first system of ribs and the second system of ribs, the first end and the second end comprising a weld region configured to be welded to the plastic tank, the first end and the second end having a second peripheral geometric shape forming a transition between the first peripheral geometric shape and a third peripheral geometric shape of the weld region, the second geometric shape and the third geometric shape corresponding to the respective geometric shapes of the surfaces projected along the axis,
• wherein the at least two secondary ribs are joined to the faces of the primary rib so as to separate each face of the primary rib into two face portions.