Spring, assembly of springs, assembly of a spring and a damper, as well as a vehicle comprising a spring

Abstract

Spring comprising a first part ( 1 ) and a second part ( 2 ) moveable relative to each other, the first part being provided with at least one permanent magnet ( 4,4′ ), the second part being provided with at least one tooth ( 5, SM of a soft magnetic material which faces the at least one permanent magnet, whereby the total area of the facing surface varies as the first part moves relative to the second part, the first and/or the second part also being provided with at least one set of electrically conductive windings ( 7 ) which are connected to an electric power supply ( 8 ) in order to create a magnetic field for influencing the force-displacement characteristic of the spring. Also disclosed is an assembly of such a spring with a conventional spring and/or a damper, as well as a vehicle provided with such a spring.

1 . A spring comprising:
 a first part and a second part, the two parts being movable relative to each other along a longitudinal axis, the first part being provided with at least one permanent magnet, the second part being provided with at least one tooth of a soft magnetic material which has a surface facing an adjacent surface of the at least one permanent magnet when the first part is in an aligned position relative to the second part, whereby the total area of the facing surfaces of the tooth and the permanent magnet varies as the first part moves relative to the second part, at least one of the first part and the second part being provided with at least one set of electrically conductive windings which are connected to an electric power supply and configured to create a magnetic field for influencing the force-displacement characteristic of the spring.   
     
     
         2 . The spring according to  claim 1 , wherein a substantially common axis of the at least one set of windings extends in a direction substantially parallel to the longitudinal axis of the spring. 
     
     
         3 . The spring according to  claim 1 , wherein the at least one set of windings is provided on the second part and the at least one permanent magnet provided on the first part is positioned relative to the at least one set of windings such that the permanent magnet moves along said set of windings when the first part moves out of the aligned position relative to the second part. 
     
     
         4 . The spring according to  claim 1 , wherein the at least one set of windings comprises a number of subsets of windings, each subset being composed of adjacent windings, the subsets being located at different longitudinal positions along the length of at least one of the first part and the second part, wherein at least one parameter of a current through the windings of a said subset is controllable by an electric power supply control so as to be different from a corresponding parameter of current through another of said subsets. 
     
     
         5 . The spring according to  claim 4 , wherein one subset of said set of windings directly face the permanent magnet and the electric power supply control is configured to direct current through the one subset of said set of windings in a first direction and to direct current through remaining windings is directed in a second direction opposite to the first direction. 
     
     
         6 . The spring according to  claim 4 , wherein a combination of windings that composes a said subset of windings is variable during operation of the spring. 
     
     
         7 . The spring according to  claim 4 , wherein a number of adjacent windings of said set of windings constitute a coil, a said subset of windings including a number of said coils. 
     
     
         8 . The spring according to  claim 7 , wherein the electric power supply control includes at least one switch connected to one coil, the one coil being connected to said power supply via said switch so that in a first position of the switch the current flows through the coil in a first direction, and in a second position of the switch the current flows through the coil in a second direction opposite to the first. 
     
     
         9 . The spring according to  claim 4 , further comprising a displacement sensing device for providing information about the distance over which the first part is displaced relative to the second part compared to a reference position, said displacement sensing device being configured to cooperate with the electric power supply control. 
     
     
         10 . The spring according to  claim 9 , wherein the electric power supply control is configured to cooperate with the displacement sensing device for regulating the currents through said different subsets of windings in dependence of the relative displacement of the first and second parts. 
     
     
         11 . The spring according to  claim 4 , wherein the electric power supply control has an input for a load sensor for providing information about force applied to the spring. 
     
     
         12 . The spring according to  claim 11 , wherein the electric power supply control is configured to cooperate with the load sensor for regulating the currents through said different subsets of windings. 
     
     
         13 . The spring according to  claim 1 , wherein the at least one set of windings constitutes a coil, and wherein the windings of the coil are in sliding contact with an electrical contact that is connectable to an electric power supply, such that the direction of the current through a subset of windings on one side of the contact is opposite to the direction of a current through the subset of windings on the other side of the contact. 
     
     
         14 . The spring according to  claim 1 , wherein the total area of the facing surfaces of the tooth and the permanent magnet is maximal when the first part is in the aligned position relative to the second part and diminishes as the first part moves out of the aligned position relative to the second part. 
     
     
         15 . The spring according to  claim 1 , wherein the second part is provided with at least two teeth, said teeth being interconnected by a soft magnetic material. 
     
     
         16 . The spring according to  claim 1 , wherein the at least one permanent magnet of the first part is mounted on a base of soft magnetic material. 
     
     
         17 . The spring according to  claim 1 , wherein the second part is provided with at least one permanent magnet, said magnet of the second part being positioned next to the at least one tooth, and said magnet of the second part being oriented such that the magnetic field of the second part magnet increasingly opposes the at least one permanent magnet provided on the first part as the first part moves out of the aligned position relative to the second part. 
     
     
         18 . The spring according to  claim 1 , wherein the windings of the at least one set of electrically conductive windings are substantially coaxial. 
     
     
         19 . The spring according to  claim 1  in combination with a conventional spring, the two springs being connected in parallel. 
     
     
         20 . The spring according to  claim 1  in combination with and a conventional spring, the two springs being connected in series. 
     
     
         21 . The spring according to  claim 1  in combination with a damping device, the spring and the damping device being connected in parallel. 
     
     
         22 . A vehicle comprising:
 a chassis,   at least one wheel, and   a suspension connecting the wheel with the chassis, the suspension having at least one spring including a first part and a second part, the two parts being movable relative to each other along a longitudinal axis, the first part being provided with at least one permanent magnet, the second part being provided with at least one tooth of a soft magnetic material which has a surface facing an adjacent surface of the at least one permanent magnet when the first part is in an aligned position relative to the second part, whereby the total area of the facing surfaces of the tooth and the permanent magnet varies as the first part moves relative to the second part, at least one of the first part and the second part being provided with at least one set of electrically conductive windings which are connected to an electric power supply and configured to create a magnetic field for influencing the force-displacement characteristic of the spring.   
     
     
         23 . A vehicle comprising:
 at least a first wheel and a second wheel,   an antiroll bar, and   an antiroll bar spring connected in series with the antiroll bar between the first wheel and the second wheel, the antiroll bar spring including a first part and a second part, the two parts being movable relative to each other along a longitudinal axis, the first part being provided with at least one permanent magnet, the second part being provided with at least one tooth of a soft magnetic material which has a surface facing an adjacent surface of the at least one permanent magnet when the first part is in an aligned position relative to the second part, whereby the total area of the facing surfaces of the tooth and the permanent magnet varies as the first part moves relative to the second part, at least one of the first part and the second part being provided with at least one set of electrically conductive windings which are connected to an electric power supply and configured to create a magnetic field for influencing the force-displacement characteristic of the spring.