Adaptable support frame profile body

Abstract

Adaptable support frame profile body (10) with a fluidically closed stiffening chamber (24) extending in a longitudinal direction (A) and filled with a magnetorheological fluid (30), characterized in that a viscosity control coil (40) is provided which is aligned in the stiffening chamber longitudinal direction (A) such that when the viscosity control coil (40) is activated, the field lines (F) generated thereby within the stiffening chamber (24) are oriented in the stiffening chamber longitudinal direction (A).

Description

[0001] The invention relates to an adaptable supporting frame profile body with the features of the preamble of claim 1 and an adaptable motor vehicle supporting frame element with a profile body

[0002] In order to adjust the stiffness of a supporting frame profile body, it is known from DE 198 55 948 A1 that the supporting frame profile body has a fluidically closed stiffening chamber filled with a magnetorheological fluid. A coil arrangement generates a magnetic field transverse to the longitudinal direction of the stiffening chamber as needed, whereby the field lines are aligned transversely when the coil arrangement is activated. This changes the degree of stiffness of a connection between a body frame and a vehicle window in order to integrate the vehicle window more closely, if necessary, to stiffen the entire vehicle body frame. However, the profile body is not significantly stiffened in the longitudinal direction of the stiffening chamber.

[0003] DE 10 2006 026 447 A1 discloses an impact absorber in a vehicle body. The foam structure is formed by a foam structure whose stiffness can be variably adjusted by a crash sensor. The foam structure is made of a polymer and the foam pores are filled with a fluid. The stiffness or compressibility of the impact absorber can be reversibly adjusted between a softer and a harder state.

[0004] From DE 11 2005 003 048 T5 a motor vehicle structural element with an active material is known which changes a mechanical or structural property of the motor vehicle structural element when an activation signal is applied.

[0005] From DE 10 2015 221 362 A1, a vehicle energy absorption device with an integrated damping medium is known, which changes its flow properties by applying an electromagnetic field.

[0006] From the generic DE 10 2009 052 716 A1 a closed profile body for a motor vehicle is known which is filled inside with a material which has magnetorheological properties and which changes the mechanical properties of the profile body when an electromagnetic field is applied in the event of a crash.

[0007] DE 101 11 199 A1 discloses an adaptable support frame profile body filled with a magnetorheological fluid. Furthermore, an electromagnetic coil is provided that can activate the magnetorheological fluid.

[0008] From WO 2014 / 000 981 A1 a vehicle frame with an adaptable cross element is known, which is equipped with a magnetorheological actuator.

[0009] The object of the invention is to provide an adaptable supporting frame profile body with an improved stiffening potential in the longitudinal direction of the profile body.

[0010] This object is achieved with an adaptable supporting frame profile body having the features of claim 1 and with an adaptable motor vehicle supporting frame element having the features of claim 6.

[0011] The adaptable support frame profile body according to the invention has a fluidically sealed stiffening chamber extending in a longitudinal direction and filled with a magnetorheological fluid. The cross-section of the stiffening chamber is uniform over the entire longitudinal extent of the stiffening chamber. The stiffening chamber is completely fluidically sealed, so that the magnetorheological fluid cannot escape.

[0012] An electromagnetic viscosity control coil is provided, the coil center of which is aligned in the longitudinal direction of the stiffening chamber such that, when the viscosity control coil is activated, the field lines generated within the stiffening chamber are oriented in the longitudinal direction of the stiffening chamber. Upon electrical activation of the viscosity control coil, i.e., when a voltage is applied to the control coil, the ferromagnetic magnetic particles align themselves in the longitudinal direction of the stiffening chamber, not in the transverse direction. This potentially massively increases the viscosity of the magnetorheological fluid, and in particular, can increase the tensile strength and compressive strength in the longitudinal direction of the stiffening chamber.

[0013] In principle, the viscosity control coil can be located outside the stiffening chamber. However, it is particularly preferred that the viscosity control coil is located inside the stiffening chamber. This ensures that, in particular, the very dense electromagnetic field within the control coil is generated entirely and transmissibly within the stiffening chamber and contributes to stiffening. However, the external electromagnetic field, i.e., the so-called electromagnetic return path, can also be generated largely or entirely within the stiffening chamber in this way and used to stiffen the profile body.

[0014] The magnetorheological fluid preferably contains magnetic particles with a predominant particle size of 3-10 µm. At least 50% of all particles have a particle size of 3-10 µm. Such a particle size enables both short mechanical reaction rates and good stiffening properties.

[0015] Preferably, the liquid phase of the magnetorheological fluid consists of a synthetic oil, for example a lubricating oil for internal combustion engines.

[0016] Preferably, the chamber housing forming the stiffening chamber is made of a non-ferromagnetic material, preferably aluminum. The chamber housing therefore has little or no influence on the field lines generated by the viscosity control coil. Particularly preferably, the entire support frame profile body is formed essentially from an extruded aluminum profile, with the stiffening chamber being closed at both ends by corresponding welded end walls.

[0017] Preferably, an adaptable vehicle support frame element is provided with a profile body according to the invention having the features of one of the patent claims directed to the profile body. In motor vehicles, severe mechanical stresses can briefly occur on the vehicle support frame during operation or in the event of a crash. By quickly stiffening the relevant vehicle support frame element, damage to the vehicle support structure can be avoided or mitigated.

[0018] Particularly preferably, the profile body forms part of a vehicle traction battery housing frame. The traction battery requires special protection in the event of a crash, as it poses a significant fire hazard if damaged. Furthermore, the traction battery housing frame can also be an important part of the overall load-bearing structure of a motor vehicle. Under high mechanical loads or in the event of a crash, the traction battery housing frame can be stiffened as needed to reduce the fire hazard posed by the traction battery.

[0019] An embodiment of the invention is explained in more detail below with reference to the drawings. They show: Fig. 1 a longitudinal section of an adaptable support frame profile body, and Fig. 2 a perspective cross-section of the supporting frame profile body of the Fig. 1.

[0020] The figures show a support frame profile body 10 which can be adapted with regard to its rigidity and which can be part of an adaptable motor vehicle support element, in particular can be part of a traction battery housing frame of a motor vehicle.

[0021] The entire support frame profile body 10 is essentially formed by a one-piece extruded aluminum profile 12, which defines a cylindrical stiffening chamber 24 in a central hollow-cylindrical chamber housing 20. The stiffening chamber 24 is completely filled with a magnetorheological fluid 30. The shape of the stiffening chamber can also be non-cylindrical. The magnetorheological fluid 30 is based on a synthetic lubricating oil mixed with ferromagnetic magnetic particles with a predominant particle size of 3-10 µm.

[0022] The chamber housing 20, which is circular in cross-section, is surrounded by an outer body 14 with a square cross-section, the four corners of which are integrally connected to the chamber housing 20 via four diagonal frames 16. The chamber housing 20 has a fluidically sealed, welded end wall 22 on each of its two end faces. The supporting frame profile body 10 extends linearly in the longitudinal direction A. The ideal profile is determined through simulation and testing.

[0023] Arranged within the stiffening chamber 24 is a viscosity control coil 40, which also extends over the entire length and in the longitudinal direction, the coil windings of which extend over the entire length of the stiffening chamber 24. The viscosity control coil 40 is electrically connected to a coil controller 100, which can generate a required coil voltage, by means of which an electromagnetic field is generated within the stiffening chamber 24 with field lines F running longitudinally within the control coil 40. As a result, the magnetic particles of the magnetorheological fluid 30 are also aligned in the longitudinal direction A, so that the magnetorheological fluid 30 solidifies and, in particular, the tensile strength and the transverse stiffness in the longitudinal direction A of the entire support frame profile body 10 are increased.

Claims

[1] Adaptable support frame profile body (10) with a fluidically closed stiffening chamber (24) extending in a longitudinal direction (A) and filled with a magnetorheological fluid (30), characterized by that a viscosity control coil (40) is provided which is aligned in the stiffening chamber longitudinal direction (A) in such a way that when the viscosity control coil (40) is activated, the field lines (F) generated thereby within the stiffening chamber (24) are oriented in the stiffening chamber longitudinal direction (A). [2] Adaptable support frame profile body (10) according to claim 1, wherein the viscosity control coil (40) is arranged within the stiffening chamber (24). [3] Adaptable support frame profile body (10) according to one of the preceding claims, wherein the magnetorheological fluid (30) comprises magnetic particles with a predominant particle size of 3-10 µm. [4] Adaptable support frame profile body (10) according to one of the preceding claims, wherein the liquid phase of the magnetorheological fluid (30) consists of a synthetic oil. [5] Adaptable support frame profile body (10) according to one of the preceding claims, wherein a chamber housing (20) forming the stiffening chamber (24) consists of a non-ferromagnetic material, and preferably consists of aluminum. [6] Adaptable vehicle support frame element with a profile body (10) having the features of one of the preceding claims. [7] Adaptable vehicle support frame element according to the preceding claim, wherein the profile body (10) is part of a traction battery housing frame.

Images