Torsion-loaded rod-shaped component with different fibre reinforcements for tensile and compressive loading

1. A torsion spring comprised of a spring wire made of fiber-composite material and including a plurality of layers of fiber reinforcement that have been saturated with a matrix material, wherein each of the plurality of layers includes only fibers that are tension-loaded or only fibers that are compression-loaded, wherein the plurality of layers comprise tension-loaded groups of layers and compression-loaded groups of layers, wherein at least one compression-loaded group of layers has a lower group stiffness than a tension-loaded group of layers with a highest group stiffness.

2. The torsion spring of claim 1 wherein said lower group stiffness is at least 10% lower than said highest group stiffness of the tension-loaded group of layers.

3. The torsion spring of claim 1 wherein at least one internally-situated compression-loaded group of layers has a lower group stiffness than a tension-loaded group of layers that is situated further outward than the at least one internally-situated compression-loaded group of layers.

4. The torsion spring of claim 1 wherein said highest group stiffness of the tension-loaded group of layers is at least 60 GPa.

5. The torsion spring of claim 1 wherein the tension-loaded group of layers with the highest group stiffness is composed exclusively of carbon fibers.

6. The torsion spring of claim 1 wherein the tension-loaded groups of layers are comprised of at least 50% by mass carbon fibers.

7. The torsion spring of claim 1 wherein a proportion by mass of at least 50% of the tension-loaded groups of layers has a group stiffness differing by less than 50% from said highest group stiffness of the tension-loaded group of layers.

8. The torsion spring of claim 1 wherein all of the tension-loaded groups of layers have a group stiffness differing by less than 50% from said highest group stiffness of the tension-loaded group of layers.

9. The torsion spring of claim 1 wherein a proportion by mass of at least 20% of the compression-loaded groups of layers has a lower group stiffness than said highest group stiffness of the tension-loaded group of layers.

10. The torsion spring of claim 1 wherein a proportion by mass of at least 50% of the compression-loaded groups of layers has a group stiffness differing by less than 50% from that of a compression-loaded group of layers with a highest group stiffness classified as low.

11. The torsion spring of claim 1 wherein all of the compression-loaded groups of layers have a group stiffness differing by less than 50% from that of a compression-loaded group of layers with a highest group stiffness classified as low.

12. The torsion spring of claim 1 wherein the compression-loaded groups of layers are comprised of a proportion by mass of at least 30% glass fibers or basalt fibers.

13. The torsion spring of claim 1 wherein at most 6 different fiber compositions are used for the tension-loaded and compression-loaded groups of layers.

14. The torsion spring of claim 1 wherein at least one pair formed from the tension-loaded group and the compression-loaded group has a group ratio in a range from 0.2 to 5.0.

15. The torsion spring of claim 1 wherein based on the spring wire and ignoring a mass of a core, a proportion by mass of the groups of layers that have formed pairs is at least 50%.

16. The torsion spring of claim 1 wherein for the layers that have a mixture of fiber compositions, a quantity of each fiber composition present in each mixed-fiber layer is at least 10% by mass.

17. The torsion spring of claim 1 wherein a proportion by mass of layers classified as non-loadbearing in the spring wire, ignoring a mass of a core, is at most 25%.

18. The torsion spring of claim 1 wherein a cross section of the spring wire is circular, elliptical, or polygonal.

19. The torsion spring of claim 1 wherein a matrix of fiber-reinforced plastics plies is comprised of a filled or unfilled thermoset plastic.

20. The torsion spring of claim 1 wherein the spring wire has a core that is hollow, that is comprised of fiber-reinforced material with unidirectional fibers in an axial direction of the spring wire, or that is comprised of material without fiber reinforcement.

21. The torsion spring of claim 1 , wherein the torsion spring is a helical spring.

22. The torsion spring of claim 1 , wherein the torsion spring is a torsion bar.

23. A method of making a torsion spring made of a multiple-ply fiber-composite material, the method comprising:

pre-designing the spring;

forming groups of fibers made of layers in contact with one another and having an identical loading direction;

determining computationally a group stiffness for each group of fibers;

adjusting the group stiffnesses of compression-loaded groups such that the compression-loaded groups have a lower group stiffness than a tension-loaded group with a highest group stiffness;

forming pairs from an inside towards an outside so that each pair comprises a tension-loaded group and a compression-loaded group that are radially adjacent;

determining a group ratio as a quotient calculated as a relationship between the group extensional stiffness values of the tension-loaded group and the compression-loaded group of each pair;

minimizing shear stresses between adjacent groups via variation of the stiffness ratios by at least one of varying a layer wall thickness, varying a type of material, or varying a fiber angle until the group ratio is in a range from 0.2 to 5; and

repeating all steps except for pre-designing the spring until a desired loadbearing capability has been achieved with a given spring stiffness profile.

24. The method of claim 23 wherein the adjusting is achieved in that at least one of a fiber material is changed, mixtures of various fiber materials are changed, or a fiber angle is altered.