SPRING UNIT, SPRING ACCUMULATOR, AND ACTUATOR

Abstract

The invention relates to a spring unit, a spring accumulator, and an actuator. The spring unit comprises at least one spring element, which has a part that can be deflected against a spring force, and a compensation device, which is designed to counteract the spring force more strongly in the case of a more greatly deflected part than in the case of a less greatly deflected part. The spring accumulator comprises such a spring unit. The actuator comprises such a spring unit and/or such a spring accumulator.

Claims

1. A spring unit comprising: at least one spring element that has a part that is deflectable against a spring force; and a compensation device configured to counteract the spring force more strongly in the case of a more greatly deflected part than in the case of a more weakly deflected part.

2. The spring unit of claim 1, wherein the compensation device comprises: a body that is deflectable with the part along a path; and one or more clamping jaws configured to clamp the body in a direction transverse to the path.

3. The spring unit of claim 2, wherein the body has a convex contour in a direction of the one or more clamping jaws, at least as considered from a part of the body bearing against the one or more clamping jaws.

4. The spring unit of claim 1, wherein the convex contour when the part is not deflected has a tangent on the one or more clamping jaws that is parallel to the path.

5. The spring unit of claim 3, wherein the convex contour when the part is more strongly deflected has a tangent on the one or more clamping jaws that is inclined relative to the path.

6. The spring unit of claim 3, wherein the convex contour is an outer contour.

7. The spring unit of claim 3, wherein the convex contour is an inner contour.

8. The spring unit of claim 1, wherein the body is resilient.

9. A spring accumulator comprising: a spring unit comprising: at least one spring element that has a part that is deflectable against a spring force; and a compensation device configured to counteract the spring force more strongly in the case of a more greatly deflected part than in the case of a more weakly deflected part.

10. The spring accumulator of claim 9, wherein the compensation device is formed with a spring accumulator.

11. An actuator comprising: a spring unit comprising: at least one spring element that has a part that is deflectable against a spring force; and a compensation device configured to counteract the spring force more strongly in the case of a more greatly deflected part than in the case of a more weakly deflected part.

12. The spring accumulator of claim 9, wherein the compensation device comprises: a body that is deflectable with the part along a path; and one or more clamping jaws configured to clamp the body in a direction transverse to the path.

13. The spring accumulator of claim 12, wherein the body has a convex contour in a direction of the one or more clamping jaws, at least as considered from a part of the body bearing against the one or more clamping jaws.

14. The spring accumulator of claim 9, wherein the convex contour when the part is not deflected has a tangent on the one or more clamping jaws that is parallel to the path.

15. The spring accumulator of claim 13, wherein the convex contour when the part is more strongly deflected has a tangent on the one or more clamping jaws that is inclined relative to the path.

16. The spring accumulator of claim 13, wherein the convex contour is an outer contour.

17. The spring accumulator of claim 13, wherein the convex contour is an inner contour.

18. The spring accumulator of claim 1, wherein the body is resilient.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1a shows, schematically in longitudinal section, a spring accumulator with a spring unit according an embodiment of an actuator with two spring elements with a deflectable part shown in a non-deflected position;

[0023] FIG. 1b shows, schematically in longitudinal section, the spring accumulator of FIG. 1a, with the deflectable part deflected further compared to FIG. 1a;

[0024] FIG. 1c shows, schematically in longitudinal section, the spring accumulator of FIG. 1a, in which the deflectable part is deflected further compared to FIG. 1b;

[0025] FIG. 2a shows, schematically in longitudinal section, a further exemplary embodiment of a spring accumulator; and

[0026] FIG. 2b shows, schematically in longitudinal section, a third exemplary embodiment of a spring accumulator.

DETAILED DESCRIPTION

[0027] The spring accumulator shown in FIGS. 1a, 1b and 1c include two compression springs 5, 10 with spring constant k that may each be deflected along an axis A. The compression springs 5, 10 are arranged oppositely from two sides 13, 17 that face towards one another and are immobile relative to one another, of an actuator (not shown in detail). The compression springs 5, 10 are oriented with deflection directions in alignment with one another (and with the axis A). The two compression springs 5, 10 are connected to one another on sides, facing away from one another, of a clamping body 20 of a compensation device for compensation of the spring force F.sub.k of the compression springs 5, 10, which spring force is dependent on the deflection.

[0028] The clamping body 20 has a longitudinal section that remains the same in different cuts parallel to the drawing plane (e.g., the clamping body 20 forms a general mathematical cylinder, the generatrix of which runs perpendicular to the drawing plane). The outer contour 25 of the longitudinal section of the clamping body 20 has a convex curved course, as considered outwardly in the direction perpendicular to the axis A.

[0029] The clamping body 20 bears, in a direction perpendicular to the axis A, against two clamping jaws 30, 35 that are oriented as roller bearings with rolling axes perpendicular to the drawing plane and are arranged fixedly relative to the sides 13, 17 of the actuator. In further exemplary embodiments (not shown specifically), the clamping jaws may also be formed as plain bearings.

[0030] The clamping body 20 is formed in a flexible manner and is clamped by the clamping jaws 30, 35, and at the same time is compressed in the direction perpendicular to the axis A and within the drawing plane. In the non-deflected position of the clamping body 20 according to FIG. 1a, the tangent at the location 40, 45 of the clamping jaws 30, 35 runs on the outer contour of the clamping body 20 parallel to the axis A. Thus, no force results, oriented along the axis A, from the clamping jaws 30, 35 on the clamping body 20. As a result of the clamping jaws 30, 35, merely a force component F.sub.y perpendicular to the axis results from each clamping jaw 30, 35. The force components are oriented oppositely one another. Since, as a result of the absence of deflection of the clamping body 20, there is also no spring force F.sub.k acting on the clamping body, there is, overall, no force acting on the clamping body 20.

[0031] With increasing deflection (FIG. 1b), the clamping body 20 experiences an increasing spring force as a result of the stronger deflection of the compression springs 5, 10. In addition, however, compared to the above-described arrangement, the clamping body bears differently against the clamping jaws 30, 35. Due to the deflection of the clamping body 20, the tangent on the outer contour of the clamping body 20, at the location 40, 45 of the clamping jaws 30, 35, for example, no longer runs parallel to the axis A, and instead is slightly inclined relative thereto in each case. Here, these tangents on the outer contour of the clamping body 20 enclose with one another an angle that is open in the direction of the deflection. As a result of this inclined bearing of the clamping jaws 30, 35 against the clamping body 20, the clamping body experiences a force in the direction of the deflection (e.g., the force conveyed by the clamping jaws 30, 35 now includes, besides the component F.sub.y perpendicular to the axis A, also a force component F.sub.x parallel to the axis A that supports the deflection; weakens the spring force counteracting the deflection of the clamping body 20).

[0032] With a further deflection of the clamping body 20, the clamping jaws 30, 35, on account of the convex outer contour of the clamping body 20 (e.g., as considered outwardly in the direction perpendicular to the axis A), bear against a point such that the tangents on the outer contour at the location of the clamping jaws 30, 35 enclose a larger angle with the axis A compared to the position according to FIG. 1b. The force component F.sub.x parallel to the axis A increases accordingly. The spring force on the clamping body 20 increasing further with stronger deflection of the clamping body 20 is weakened with a further increased force component F.sub.x.

[0033] The contour of the clamping body 20 in the shown exemplary embodiment has such a course that the total force acting on the clamping body 20 along the axis A is practically constant (e.g., is practically independent of the deflection of the clamping body 20).

[0034] In the extreme case, the outer contour of the clamping body 20 may be selected in a further exemplary embodiment (not shown specifically) such that the force F.sub.x conveyed by the clamping jaws 30, 35 always offsets the spring force F.sub.k on the clamping body 20. The clamping body 20 thus remains free of force with each deflection. Consequently, the clamping body 20 is stopped in each deflected position in exemplary embodiments of this kind.

[0035] The clamping jaws 30, 35 do not have to act on the outer contour of the clamping body 20 as presented above. Rather, the clamping body 20 may have a corresponding inner contour that is acted on by the clamping jaws 30, 35, as shown in FIG. 2a.

[0036] The clamping body 50 presented in FIG. 2a has the form of a hollow general mathematical cylinder (e.g., the base of the cylinder is biconnected and has the topology of a circular ring that in the present case is suitably deformed). The clamping body 50, in planes parallel to the drawing plane, has an inner contour that has a convex shape as considered from the part of the clamping body 50 bearing against each inner clamping jaw 30, 35 in the direction of the clamping jaws 30, 35.

[0037] In this exemplary embodiment, the spring force may be suitably compensated, may be linearized in relation to the deflection, and/or may be cancelled out completely.

[0038] The clamping body does not have to have the form of a general mathematical cylinder. Rather, the clamping body may also have a rotationally symmetrical design, as shown in FIG. 2b. The clamping body 70 shown in FIG. 2b has the same longitudinal section as the clamping body 20 shown in FIGS. 1a to 1c. In contrast to the clamping body 20, the clamping body 70, however, results from rotation of the longitudinal section about the axis A. The clamping jaws 90 are in this case ball bearings.

[0039] In a further exemplary embodiment (not shown specifically), the clamping body results from rotation of the longitudinal section of the clamping body 50. In this case as well, the clamping jaws (not shown specifically) are provided by ball bearings.

[0040] In further exemplary embodiments (not shown specifically), which, for the rest, correspond to those described above, the spring elements do not satisfy Hooke's law. Rather, in many cases encountered in practice, the spring constant is not an actual constant, and instead, is dependent on the deflection s. The spring force, therefore, has a non-linear dependency of the spring force F on the deflection s:

F=k(s)*s,

where k(s) describes the spring stiffness now dependent on the deflection. In this case, the clamping body 20 may be configured to compensate for the spring force that follows from this non-linear characteristic or to compensate or weaken the increase/decrease thereof with increasing deflection.

[0041] In order to compensate for a non-linear spring force of this kind in the entire deflection range, the form of the clamping body is modified compared to the drawing. If, for example, k(s) increases with the deflection s, the curvature of the clamping body in the non-deflected position thereof is to be lower and is to be higher accordingly at the edge compared to that shown in FIG. 1 and FIG. 2. If k(s) decreases with the deflection s, the curvature of the clamping body in the middle thereof is higher and is lower at the edge thereof accordingly.

[0042] The elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present invention. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent. Such new combinations are to be understood as forming a part of the present specification.

[0043] While the present invention has been described above by reference to various embodiments, it should be understood that many changes and modifications can be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.