LOCK WASHER FOR A SCREW CONNECTION, AND SCREW CONNECTION

Abstract

A lock washer for a screw connection between a screw part and a component, having an annular washer body which is delimited by a peripheral outer rim and an inner rim, having a receiving bore, delimited by the inner rim, into which the screw part is insertable, having an upper annular surface which is provided on an upper side of the washer body and has a toothing, having a lower annular surface which is provided on a lower side of the washer body and has a toothing which extends fully on the lower annular surface, wherein the toothing on the upper annular surface extends fully circumferential in a toothed region, the width of the toothed region on the upper annular surface is smaller than the width of the washer body between the outer rim and the inner rim, and an untoothed region is formed on the upper annular surface between the toothed region and the outer rim of the washer body.

Claims

1. A lock washer for a screw connection between a screw part and a component, having an annular washer body which is delimited by a peripheral outer rim and an inner rim, having a receiving bore, delimited by the inner rim, into which the screw part is insertable, having an upper annular surface which is provided on an upper side of the washer body and has a toothing, having a lower annular surface which is provided on a lower side of the washer body and has a toothing which extends fully on the lower annular surface, wherein the toothing on the upper annular surface extends fully circumferential in a toothed region, the width of the toothed region on the upper annular surface is smaller than the width of the washer body between the outer rim and the inner rim, and an untoothed region is formed on the upper annular surface between the toothed region and the outer rim of the washer body.

2. The lock washer according to claim 1, wherein the width of the toothed region on the upper annular surface is smaller than the width of the toothing on the lower annular surface.

3. The lock washer according to claim 1, wherein the toothed region is surrounded on one side by the untoothed region.

4. The lock washer according to claim 1, wherein the toothed region on the upper annular surface extends from the inner rim of the washer body only partially to the outer rim and is delimited by the untoothed region which extends from the toothed region to the outer rim of the washer body.

5. The lock washer according to claim 1, wherein the width of the toothed region is greater than that of the untoothed region, or the width of the toothed region is equal to the width of the untoothed region, or the width of the toothed region is smaller than the width of the untoothed region.

6. The lock washer according to claim 1, wherein the washer body is set up in the manner of a plate spring.

7. The lock washer according to claim 1, wherein the toothing on the upper and/or lower annular surface is formed as a helical toothing.

8. The lock washer according to claim 1, wherein the untoothed region is formed as a flat surface.

9. The lock washer according to claim 1, wherein a flattening is provided on the lower annular surface adjacent to the outer rim, which flattening provides an outer circular boundary for the toothing, which extends to the inner rim.

10. The lock washer according to claim 1, wherein the upper annular surface has, adjacent to the inner rim, a flattening which forms an inner circular boundary for the toothed region, which extends to the untoothed region.

11. The lock washer according to claim 1, wherein the washer body is made of a spring steel, a high-strength or heat-resistant or corrosion-resistant steel.

12. The lock washer according to claim 1, wherein the washer body has a hardness of equal to or greater than 200 HV.

13. A screw connection having a component and a screw part fastened thereto, which is formed as a screw and/or a screw/nut combination, and at least one lock washer positioned between the component and the screw part, wherein the lock washer is formed according to claim 1.

14. The screw connection according to claim 13, wherein the component is made of a steel, a light metal alloy or a plastic with a surface hardness of equal to or less than 200 HV.

15. The screw connection according to claim 13, wherein the component has a threaded hole, a through hole or an elongated hole.

16. The screw connection according to claim 13, wherein the width of the toothed region on the upper annular surface of the washer body is equal to or greater than a diameter of a screw head or a peripheral surface on the underside of the screw head of the screw part.

17. The screw connection according to claim 13, wherein the screw part is subjected to a pre-tensioning force to the component for locking the screw part, and a lock washer is provided, in which the size of the annular surface of the lock washer is enlarged such that, with the pre-tensioning force for securing the screw part to the component, the effective surface pressure, which results from the pre-tensioning force divided by the annular surface of the lock washer, has a value of less than 200 N/mm.sup.2.

Description

[0022] The invention and other advantageous embodiments and developments thereof are described and explained in more detail below using examples depicted in the drawings. The features to be taken from the description and the drawings can be applied individually or in any combination in accordance with the invention. Here are shown:

[0023] FIG. 1 a schematic view of an underside of a lock washer,

[0024] FIG. 2 a schematic sectional view of the lock washer according to FIG. 1,

[0025] FIG. 3 a schematic view from above of the lock washer according to FIG. 1,

[0026] FIG. 4 a perspective view from above of the lock washer according to FIG. 1,

[0027] FIG. 5 a perspective view from below of the lock washer according to FIG. 1,

[0028] FIG. 6 a schematic sectional view of a screw connection in the untensioned state,

[0029] FIG. 7 a schematic sectional view of the screw connection according to FIG. 6 in the tensioned state,

[0030] FIG. 8 a schematic view from above of an alternative screw connection, and

[0031] FIG. 9 a schematic view from below of the screw connection according to FIG. 8.

[0032] FIG. 1 depicts a schematic view from below of a lock washer 11. FIG. 2 shows a schematic sectional view along the line I-I in FIG. 1. FIG. 3 shows a schematic view from above of the lock washer 11 according to FIG. 1. FIG. 4 shows a perspective view from above and FIG. 5 shows a perspective view from below of the lock washer 11 according to FIG. 1.

[0033] This lock washer 11 comprises a washer body 12, which is annularly formed. This washer body 12 comprises a lower annular surface 14, which is depicted in FIG. 1, and an upper annular surface 16, which is depicted in FIG. 3. The upper and lower annular surfaces 14, 16 are each delimited by a peripheral outer rim 17 and a preferably concentric inner rim 18. The inner rim 18 delimits a receiving bore 19, which is provided for the insertion of a screw part 21 (FIG. 4). A toothing 23 is provided on the inner annular surface 14, which extends fully peripherally. Furthermore, the toothing 23 extends over the entire width of the annular surface 14, namely from the inner rim 18 to the outer rim 17.

[0034] Adjacent to the outer rim 17 and in the direction of the toothing 23, a lower flattening 25 is provided, such that the teeth of the toothing 23 adjacent to the outer rim 17 are flattened. The flattening 25 can be even or rounded. The toothing 23 on the lower side is preferably formed as a helical toothing. Such a toothing 23 can be produced by stamping.

[0035] The lock washer 11 according to FIGS. 1 to 3 preferably has an upright washer body 12. This is shown in the sectional view according to FIG. 2. The washer body 12 is formed in the manner of a plate spring. An inner rim 18 of the washer body 12 is raised relative to an outer rim 17. This enables this lock washer 11 to generate a tensioning force acting on a screw connection.

[0036] The top view of the upper annular surface 16 of the lock washer 11 shows that a toothed region 26 and an untoothed region 27 are provided. The toothed region 26 comprises a toothing 22 extending fully within the toothed region 26. This toothed region 26 on the upper annular surface 16 is smaller in width, in any case, than the width of the upper annular surface 16 that is, between the outer rim 17 and the inner rim 16. The width of the toothed region 26 within which the toothing 22 extends is formed to be smaller than the toothing 23 on the lower annular surface 14, which extends on the lower annular surface 16 between the inner rim 18 and the outer rim 17. The toothed region 26 extends fully circumferential on the upper annular surface 16. The toothed region 26 can merge into an upper flattening 24 extending to the inner rim 18. From there, the toothed region 26 extends, as seen in the width, in the direction of the outer rim 17. Between the toothed region 26 and the outer rim 17 of the washer body 12, the untoothed region 27 extends fully peripherally. This untoothed region 27 advantageously has a flat surface. The width of the toothed region 26 or that of the untoothed region 27 can be selected depending on the hardness of the surface of the component 32. The width of the toothed region 26 can be equal to, greater than or less than the width of the untoothed region 27. The toothed region 26 is preferably also designed as a helical toothing. The design of the helical toothing can be the same for both the lower annular surface 14 and the toothed region 26 of the upper annular surface 16.

[0037] The lock washer 11 is preferably made of a spring steel, a high-strength or a heat-resistant or corrosion-resistant steel. The lock washer 11 can have a hardness of greater than 200 HV.

[0038] FIG. 6 shows a screw connection 31 in an untensioned state between a component 32 and the screw part 21 with the interposition of the lock washer 11. In this first embodiment, the screw part 21 is designed as a screw with a screw head 34 and a thread 35. Alternatively, the screw part 21 can also be formed as a threaded pin having a nut attached thereto. In these cases, the component 32 comprises a threaded hole 36. Alternatively, it can be provided that the component 32 comprises a through hole such that another component not depicted in more detail can be fastened or held by a screw connection 31 having a screw part 21 comprising a screw/nut combination or a threaded pin/nut combination.

[0039] The screw head 34 of the screw part 21 preferably has a peripheral flat annular collar on its side facing the lock washer 11. The width of the toothed region 26 on the upper annular surface 16 of the lock washer 11 preferably corresponds to the width of the annular collar on the underside of the screw part 21. The untoothed region 27 extends radially peripherally beyond the underside of the screw part 21. The outer rim 17 of the lock screw 11 is larger in diameter than the screw head 34 of the screw part 21.

[0040] In the tensioned state of the lock washer 11 according to FIG. 7, the toothing 23 engages positively on one surface of the component 32. On the opposite side, a form fit is achieved between the toothed region 26 of the lock washer 11 and a screw head or the annular collar of the screw head 34 of the screw part 21. In addition, the lock washer 11 provides a complete force fit of the screw connection between the component 32 and screw part 21 due to the plate spring-like curved geometry.

[0041] FIG. 8 depicts a schematic view from above and FIG. 9 depicts a schematic view from below of an alternative embodiment of the screw connection 31. In this embodiment, the component 32 surrounds an elongated hole 37. The enlarged outer diameter of the lock washer 11 has the advantage that a lower annular surface 14 is supported on the component 32 adjacent to the elongated hole 37 and can achieve a secure form fit connection. The toothed region 26 on the upper side of the lock washer 11 corresponds in width, for example, to the outer circumference of a lower side of the screw part 11.