Spring For A Vehicle

Abstract

A spring, in particular a flat spring (5), for use in connection with a vehicle, has a middle region (6) which has a curve with a first curve direction, as well as two edge regions (7). In an unladen state, the edge regions (7) each have a curve with a second curve direction and vertices (10), with the second direction of curve being opposed to the first direction of curve. The flat spring (5) has a vertex axis (11) running through the vertices (10) of the curves of the edge regions (7). End regions (8) of the edge regions (7) are tilted away from the vertex axis (11) toward the side of the vertex axis (11) on which the middle region (6) lies.

Claims

1. A spring, in particular a flat spring (5), for use in connection with a vehicle, with a middle region (6) which has a curve with a first curve direction, as well as two edge regions (7), characterized in that, in an unladen state, the edge regions (7) each have a curve with a second curve direction and vertices (10), with the second direction of curve being opposed to the first direction of curve, in that the flat spring (5) has a vertex axis (11) running through the vertices (10) of the curves of the edge regions (7), and in that end regions (8) of the edge regions (7) are tilted away from the vertex axis (11) toward the side of the vertex axis (11) on which the middle region (6) lies.

2. The spring according to claim 1, characterized in that the edge regions (7) are shaped symmetrically or asymmetrically with regard to one another.

3. The spring according to claim 1, characterized in that it contains spring steel and/or composite material.

4. The spring according to claim 3, characterized in that the composite material features glass fibers, which are preferably embedded in the synthetic material of the composite material as reinforcing elements.

5. The spring according to claim, characterized in that the composite material includes thermosetting resin or thermoplastic resin.

6. The spring according to claim 5, characterized in that the composite material features polyurethane and/or polyamide and/or polyester.

7. The spring according to claim 1, characterized in that fibers, in particular glass fibers, are arranged on the surface of the flat spring (5), which run essentially parallel to the vertex axis (11), in particular from one edge region (7) to the opposite edge region (7).

8. The spring according to claim 1, characterized in that at least one end region (8) is tilted by an angle (α) away from the vertex axis (11) toward the side of the vertex axis (11), on which the middle region (6) lies, with the angle (α) lying between 1° and 135°, preferably in the range of 10° to 90°, especially preferably in the range of 20° to 60°, in particular 45°.

9. A method of use of a spring according to claim 1, characterized in that a force vector (14) applied to the middle region (6) is oriented toward the vertex axis (11), and force vectors applied to the end regions (8) point in the opposite direction.

10. A method of use of a spring according to claim 9, characterized in that the vertex axis (11) lies above the middle region (6) in an assembled state.

11. A vehicle characterized by at least one spring according to claim 1.

Description

[0020] FIGS. 1 and 2 show a two-part flat spring according to the state of the art in various load states,

[0021] FIG. 3 shows the spring characteristic curve of the flat spring according to FIGS. 1 and 2,

[0022] FIG. 4 shows an embodiment of a one-piece flat spring according to the invention,

[0023] FIGS. 5 to 14 show the flat spring according to FIG. 4 in various load states,

[0024] FIG. 15 shows the spring characteristic curve according to FIGS. 10 through 14,

[0025] FIG. 16 shows a use of the flat spring according to FIGS. 4 through 14, and

[0026] FIG. 17 shows a further embodiment of a one-piece flat spring according to the invention.

[0027] FIGS. 1 and 2 show a two-part flat spring familiar from the state of the art in various load states. FIG. 1 corresponds to an essentially unladen state. The deformation of the flat spring 5 shown in FIG. 2 corresponds to a loaded state in which the vehicle is loaded.

[0028] The known flat spring comprises a first part of the spring 1 with a middle region 2 and two edge regions 3. The first part of the spring 1 is aligned in its middle region 2 with a second part of the spring 4. In an unladen state, the edge regions 3 are distanced from the second part of the spring 4. As the load increases, the two edge regions 3 approach the second part of the spring 4, up to the point where they abut the second part of the spring 4. Up to the point where the edge regions 3 abut the second part of the spring 4, a flat spring has a relatively flat, approximately linear spring characteristic curve, as shown in FIG. 3. The spring characteristic curve shows the connection between deformation (distance) of the flat spring and a force which acts on the flat spring. Upon further, increasing load, the first part of the spring 2 and the second part of the spring 4 are deformed together. From this point onward, the flat spring has a steeper, again approximately linear spring characteristic curve. The spring characteristic curve displays a bend which in particular negatively influences driving quality. The transition from a “soft” suspension to a “hard” suspension thereby is erratic. The spring rate drops intermittently with rising load. To make the transition smoother, using multi-part flat springs (for instance three-part of four-part) rather than a two-part construction is well established in the state of the art. A truly progressive spring characteristic curve, on the one hand, is not thereby achieved. On the other hand, the known problems are amplified by the high dead weight of the spring.

[0029] FIG. 4 shows an embodiment of a one-part flat spring 5 according to the invention. The flat spring 5 has a middle region 6 which has a curve with a first curve direction, as well as two edge regions 7, each with an end region 8. The middle region 6 has a base region 16 which essentially runs straight.

[0030] In an unladen state, the edge regions 7 each has a curve with a second curve direction and vertices 10, with the second curve direction opposed to the first curve direction. The flat spring 5 displays a virtual vertex axis 11 running through the vertices 10 of the curves of the edge regions 7, with the end regions 8 of the edge regions 7 tilted away from the vertex axis 11 to the side of the vertex axis 11, on which the middle region 6 lies. In the embodiment shown, the end regions 8 are tilted at an angle α of essentially 45° to the vertex axis 11. The end regions 8 display a curved section 17 and an essentially straight end section 18.

[0031] The end regions 8 each display a device 9 for connecting the flat spring 5 with a chassis of a vehicle, with these devices 9 being rolled eyes in the embodiment shown. For the flat spring 5 according to the invention, other devices 9 can also be envisioned for connecting the flat spring 5 with the chassis of a vehicle. Depending on the type of flat spring 5, both devices 9 can be an eye. A device 9 can also be a rolled or shaped eye, for instance incorporated in the end region 8, eye, whereas the other end region 8 can essentially be flat.

[0032] FIGS. 5 to 9 show how the flat spring 5 is deformed under an increasing load, beginning with FIG. 5 on to FIG. 9. An effective length 12 of the flat spring 5 is indicated, which becomes shorter beginning with FIG. 5 to FIG. 9, which leads to an increased gradient of the spring characteristic curve (FIG. 15), thus to a rising spring rate.

[0033] In FIG. 5 the flat spring 5 is shown in an essentially unladen state, with the effective length 12 of the flat spring 5 essentially being the length of the flat spring 5, since the flat spring 5 flexes significantly over its entire length under a load. Under an increasing load, the edge regions 8 tilt more strongly toward the middle region 6, i.e. the edge regions tilt more strongly away from the vertex axis 11. Due to the force vector applied there at a reduced angle with regard to the longitudinal direction of the end region, the bending moment becomes smaller in the edge region, so that the edge regions 8 flex less.

[0034] Thereby, the effective length 12 of the flat spring 5 is reduced, until it only has the length of the distance between the two vertices 10 in the state shown in FIG. 9. The reduction of the effective length 12 of the flat spring 5 in connection with the rising load results in a progressive spring characteristic curve. The spring rate also drops continuously under an increased load and dependent thereon.

[0035] Additionally, various points of the spring characteristic curve are marked in FIG. 15 which correspond to certain load states. These load states match corresponding formed or deformed, respectively, flat springs 5 according to FIGS. 10 to 14, with the load states according to FIGS. 10 to 14 corresponding to the depictions of the load states of the flat spring 5 according to FIGS. 5 to 9.

[0036] In FIG. 16, a use of the flat spring 5 according to the invention is shown, whereby it is indicated that the regions of the vertices 10 are associated with bump stops 13.

[0037] FIG. 17 shows an embodiment of a flat spring 5 according to the invention in which the device for connecting the flat spring 5 with the chassis of a vehicle are not rolled eyes 9. Rather, it is envisioned in this embodiment that the flat spring 5 is firmly connected with the chassis. This can be done with or without an intermediary piece, for instance through welding and/or by means of bolts.

[0038] All shown embodiments of flat springs 5 according to the invention have in common that a force vector 14 exerted on the middle region 6 (FIG. 4) is pointed toward the vertex axis 11, and force vectors 15 exerted on the end regions 8 point in the opposite direction.

[0039] The invention was described with reference to a flat spring. The technical effect according to the invention also occurs with other cross section types, for instance rod-like springs, so that the invention also extends to other forms than flat springs.

[0040] Summarizing, an example embodiment of the invention can be described as follows:

[0041] A spring, in particular a flat spring, for use in connection with a vehicle, has a middle region 6, which has a curve with a first curve direction, as well as two edge regions 7. In an unladen state, the edge regions 7 each have a curve with a second curve direction and vertices 10, with the second direction of curve being opposed to the first direction of curve. The flat spring 5 features a vertex axis 11 running through the vertices 10 of the curves of the end regions 7. End regions 8 of the edge regions 7 are tilted away from the vertex axis 11 toward the side of the vertex axis 11 on which the middle region lies.