BEARING ASSEMBLY

Abstract

The invention relates to a bearing assembly (10) comprising at least one first bearing element (12) and a second bearing element (14) which are rotatably connected relative to each other along a common longitudinal axis (14). The bearing assembly (10) comprises a brake device (18) which inhibits the rotation of the two bearing elements (12) relative to each other by means of a frictional force produced by the brake device (18), wherein the brake device (18) has at least one frictional element (20) and at least one clamping device (22), by means of which the frictional element (20) is permanently clamped against one of the two bearing elements (12). The bearing assembly also comprises a coupling device (30) which can be moved between an open state and a closed state. In the closed state, the brake device (18) is engaged, whereby when the two bearing elements (12) rotate relative to each other, the rotation is inhibited by the frictional force produced by the brake device (18), and in the open state, the brake device (18) is disengaged.

Claims

1. A bearing assembly comprising at least one first bearing element and one second bearing element which are rotatably coupled relative to each other along a longitudinal axis, wherein the bearing assembly comprises: a brake device, which inhibits relative rotation of the at least first and second bearing elements to each other by a frictional force produced by the brake device, wherein the brake device has at least one frictional element and at least one clamping device by which the frictional element is permanently clamped against one of the at least first and second bearing elements, and a coupling device which is adjustable between an open state and a closed state, wherein in the closed state the brake device is engaged, whereby during a rotation of the at least first and second bearing elements relative to each other, said rotation is inhibited by the frictional force produced by the brake device (18), and wherein in the open state, the brake device is disengaged, whereby the at least first and second bearing elements are rotatable relative to each other without being inhibited by the brake device.

2. The bearing assembly according to claim 1, wherein the clamping device is configured to permanently clamp the at least one frictional element against one of the at least first and second bearing elements by using an adjustable pretension force.

3. The bearing assembly according to claim 1, wherein the at least one clamping device comprises: a split or an unsplit clamping collar; a bent wire having a thread on both ends and being clamped by a clamping nut; a steel rope which is hooked into a clamping element of the clamping device; and a steel rope or a steel belt, which is clamped by a clamping element, which is annularly arranged around the bearing element, and is clamped to the clamping element on ends thereof.

4. The bearing assembly according to claim 1, wherein the bearing assembly comprises a casing, wherein the brake device or the coupling device is arranged outside of, or within, the casing.

5. The bearing assembly according to claim 1, wherein the coupling device comprises: a gearing being aligned radially inside on one of the at least first and second bearing elements, and positioned on one of the at least first and second bearing elements, which is not clamped against the frictional element; and a corresponding gearing being aligned radially to an outside on the frictional element, wherein the gearings engage with each other in a closed state of the coupling device and are not engaged with each other in the open state of the coupling device.

6. The bearing assembly according to claim 5, wherein at least one of the gearings is arranged on the coupling element which is movable along a longitudinal direction.

7. The bearing assembly according to claim 1, wherein the coupling device remains in the closed state in case it is not operated.

8. The bearing assembly according to claim 1, wherein the coupling device comprises an electromagnetic actuator.

9. The bearing assembly according to claim 1, wherein the coupling device comprises a transmission device by which a power for adjustment between the open state and the closed state may be transferred, or a pretension force of the clamping device may be transferred.

10. The bearing assembly according to claim 7, wherein the coupling device remains in the closed state in case it is not operated when the coupling device is pretensioned by a spring element (40) in the closed state.

11. The bearing assembly according to claim 9, wherein the transmission device comprises two wedge elements which slide down on respective wedge faces thereof during adjustment.

12. The bearing assembly according to claim 3 wherein the clamping element includes at least one of a rocker lever, an endless steel rope, or an endless steel belt.

13. The bearing assembly according to claim 8 wherein the electromagnetic actuator includes at least one of an electromagnet or a solenoid, a drive element as a servomotor, a Bowden cable, a hydraulic actuator or a pneumatic actuator.

14. The bearing assembly according to claim 13 wherein the hydraulic actuator or the pneumatic actuator is pressurizable and includes an expandable pressure hose for adjustment between the closed and the open states.

Description

[0044] Further features of the invention become apparent from the claims, the exemplary embodiments and the figures. The features and the combination of features mentioned in the specification above and the features and combinations of features mentioned in following exemplary embodiments may be used not only in the respective specified combination, but also in other combinations within the scope of the invention.

[0045] Here shows:

[0046] FIG. 1 in a schematic section view a bearing assembly comprising a brake device and a coupling device;

[0047] FIG. 2 in a detailed section view a portion of the bearing assembly according to FIG. 1;

[0048] FIG. 3 in a schematic perspective view the bearing assembly according to FIG. 1;

[0049] FIG. 4 in a schematic section view a portion of the bearing assembly according to FIG. 3; and

[0050] FIG. 5 in a schematic perspective view a further exemplary embodiment of the bearing assembly.

[0051] FIG. 1 shows in a schematic section view a bearing assembly 10, which comprises a first bearing element 12, which is embodied as a rotor in the present embodiment. Further, the bearing assembly 10 comprises a second bearing element which is rotatable relative hereto about the longitudinal axis 14, which is configured as stator in the present embodiment and is not shown in FIG. 1. In addition, the bearing assembly comprises a cover plate 16 which is connected to the stator in a rotatably fixed way.

[0052] Further, the bearing assembly 10 comprises a brake device 18, which comprises a brake ring 20, and a clamping collar 22. As in particular is shown clearly in the schematic perspective views of FIG. 3 and FIG. 4, wherein the bearing assembly 10 is shown only as cutout and sectioned in FIG. 4, the brake ring 20 is thus at least partly accommodated by means of the clamping collar 22 in a radially peripheral recess 24 of an outer peripheral surface 26 of the bearing element 12. This way, the brake ring 20 is axially fixed and may not be moved along the longitudinal axis 14. As is further shown in FIG. 3, the brake ring 20 consists of a plurality of pieces, thus it is easy to mount and disassemble. The brake ring 20 may thus be a wear part or comprise wear parts, which are abrased during generation of a frictional force. Therefore, the clamping collar 22 clamps a brake ring 20 permanently against the bearing element 12, and may also be denoted as part of the clamping device. For the purpose of clamping, the clamping collar 22 may be contractable by means of a screw connection 28 in order to increase or reduce the pretension, and to press the brake ring 20 thus stronger or less strong against the bearing element 12. This way, a respective frictional force may be adjusted, which is generated, in case the rotor and the stator of the bearing assembly 10 are rotated relative to each other about the longitudinal axis 14. Here, said frictional force acts against said rotation, which may also be denoted as braking or inhibiting the rotation.

[0053] The brake device 18 or the brake ring 20 may thus be connected to the cover plate 16, whereby the brake ring 20 is moved relatively to the bearing element 12 about the longitudinal axis 14, in case the rotor or bearing element 12 rotates relative to the stator. The brake ring 20 may for example stay in the same position like the second bearing element, which is shown, if the bearing element 12 rotates about the longitudinal axis 14. This way, due to the brake ring 20 which is clamped against the outer peripheral surface 26 of the bearing element 12, a braking force is generated between the respective faces which are here pressed one against the other, which inhibits the rotation. Thus, an increased force for moving the rotor is required. This is for example useful in case a carrier arm of a support device for medical devices is connected to the rotor. This way, medical devices may be moved in a precise and reliable way, in addition, the bearing assembly 10 may thus remain in a respective position without exerting a force on the medical devices and/or against gravity. At the same time, the frictional force may be adjusted in a way that any undesired movement, for example an unintended bouncing against the carrier, is significantly reduced or may even be completely inhibited.

[0054] Sometimes however a fast movement by leveraging little force is desired. In said case, a coupling device 30, which is especially shown in detail in FIG. 2, which represents the enlarged cutout designated by Z of FIG. 1, may be adjusted between the open state and the closed state. The coupling device enables thus to switch the braking function on and off. In the figures the closed state is shown, respectively. In the closed state, the brake device 18 is engaged, whereby during rotation of the rotor relative to the stator, the movement of the rotor is inhibited by the frictional force generated by the brake device 18. The frictional force which has been generated by the brake device 18 also acts against rotation. A flow of force between the cover plate 16 and the bearing element 12 is thus closed by the coupling device 30. For this purpose, the coupling device 30 comprises a coupling ring 32, which comprises a gearing on the portion 34 radially inside, which is engaged in a gearing extending radially outside of brake ring 20. The gearings are also aligned in the radial direction. An engagement may here be provided only on one peripheral surface, or may be formed by completely peripheral gearings.

[0055] In case the coupling device 30 is to be adjusted to the open state, the engagement of the respective gearings has to be released. In the present example, the coupling ring 32 has to be moved along the longitudinal axis 14 upward in the longitudinal direction. For this purpose, the coupling ring 32 is rotatably fixed, however axially movable mounted to the cover plate 16 using the respective guide bolt 36. However, the guide bolts 36 may also be directly mounted to the stator, thus a cover plate may be omitted. Further, the coupling device 30 comprises hereto an electromagnet 38. The electromagnet 38 is coupled to the coupling ring 32. In case of activating the electromagnet 38, for example by applying an electric voltage, the electromagnet 38 is pulled by the thus generated magnetic force together with the coupling ring 32 to the cover plate 16. Hereby, the coupling ring 32 is moved along the longitudinal axis 14 upwards, whereby the engagement of the gearing in the portion 34 is released. In the thus generated open state, the brake device 18 is disengaged, whereby the rotor may be rotated without being inhibited by the brake device 18 relative to the stator around the longitudinal axis 14. Said rotation will then be only inhibited insofar as respective other frictional forces may exist in the bearing assembly 10. For example, a certain inhibition may be generated by rolling down and/or sliding down of respective balls of a ball bearing or respective sliding faces of bearing assembly 10. In the open state, the rotor may be moved relative to the stator in a fast way and with little force.

[0056] Due to security reasons, in particular during usage of the bearing assembly 10 in a surgery room for supporting respective medical devices by means of carrier arms supported by using the bearing assembly, the coupling device 30 is pretensioned in the closed state thereof. The bearing assembly 10 or the coupling device thus automatically returns to the close state as soon as the electromagnet 30 is deactivated. Hereto, the coupling device 30 comprises respective pressure springs 40 which are arranged on or at the respective guide bolts 36. By said positioning of the pressure springs 40, they are also supported by the guide bolts 36 and are in addition accommodated in a particular space-saving way. By means of the pressure springs 40, the coupling ring 32 is pressed against respective nuts 42 which are fitted onto the guide bolt 36. The respective nuts 42 serve here as abutment and specify a position for the closed state, in which the respective gearings of the coupling ring 32 and the brake ring 20 are engaged with each other in the portion 34. Preferably, the respective pressure springs 40 are dimensioned in a way that the coupling device 30 remains in the closed state independent of its position and also against gravity.

[0057] In the bearing assembly 10, the operation force which is required for releasing the brake effect is independent of the set pretension for generating the frictional force. Thus, for disengagement, the pretension, which acts on the brake ring 20 which is configured as friction element having the clamping collar 22, has not to be overcome. In addition, the pretension does not have to be suspended or released. Instead, for example only the spring force of the respective pressure springs 14 and a friction of the gearing in the portion 34 has to be overcome. The forces, which are required for disengaging the brake device 18, may thus be substantially smaller. Correspondingly, a very small and cost-efficient electromagnet 38 may be used, for example.

[0058] At the same time, respective effectively acting dimensions of the respective pairs of brake surfaces, that is the clamped surfaces between brake ring 20 and bearing element 12, may be configured independently of the coupling device 30. Hereby, a high brake torque may be achieved by the same pressure force, or by a smaller pressure force the same brake torque as in a bearing assembly, in which only small surfaces are available for generating the frictional force in a region of a coupling device. For a large surface, and correspondingly hereto only a small pressure for generating an otherwise identical brake torque, the abrasives wear of the brake device 18 may be especially low. As the coupling device 30 itself is not required for generating the inhibiting frictional force, it may be consist of cost efficient and lightweight parts, for example, of resin parts. The coupling device is subjected to only little wear during engagement and disengagement and is not further worn by the actual generation of the frictional force. Therefore, the gearing may be formed as a resin gearing, for example, while a high frictional force may still be achieved due to the pretension using a metal clamp collar 22.

[0059] The brake force which may be generated is not limited by the technical capabilities to open or disengage the coupling device 30. In particular, no precise gap has to be provided between the electromagnet 38 and the cover plate 16, in order to keep to a predefined brake torque, as the electromagnet 38 does not specify the inhibiting frictional force by itself. The generated frictional force may be simply adjusted by a user by rotating the screw connection 28, for example by means of a screwdriver. Basically, a plurality of actuators having different active principles may be used instead of the electromagnet 38 for adjusting the coupling device 30.

[0060] In addition, as is shown in the figures, the coupling device 30 and also the brake device 18 are arranged radially outside of the bearing element 12. Thus, for example, the screw connections 28 is particularly well accessible for adjustment of the pretension and thus a simple setting of the inhibiting frictional force. In addition, the brake ring 20 is easily accessible, thus it may easily be replaced in case of wear. Due to the screwing connection 28, the pretension force may be easily re-adjusted after occurrence of wear of the brake ring 20, thus the inhibiting brake force is not necessarily reduced by abrasion in the course of time. Also, the coupling device 30 is thus easily accessible for maintenance. In addition, the respective parts of the brake device 18 and the coupling device 30 may be standardized, as the mounting space is barely limited from outside. Respective parts, outer parts have to be only slightly adapted to the available mounting space.

[0061] However alternatively, the coupling device 30 and/or the brake device 18 may also be arranged relative to the longitudinal axis 14 radially inside to the bearing element 12 and/or the stator and/or the cover plate 16. This way, the coupling device 30 and/or brake device 18 are well protected against undesired manipulations, damages and/or contamination. In addition, it may thus be prevented that a user pinches his/her finger in a gap of the coupling device 30, without requiring any additional enclosure or casing. In addition, the bearing assembly 10 may thus be in particular small. The bearing element 12 may here also be formed as a part of the bearing casing as well as the stator and/or the cover plate 16.

[0062] FIG. 5 shows in a schematic perspective view, a further exemplary embodiment of the bearing assembly 10. The clamping device 22 is here designed in a different way. Instead of a steel belt including the screw connection 28, a wire is used for tensioning the brake ring 20, which comprises opposite threads on both ends thereof, and a thread nut 44. Here, the thread nut 44 comprises the respective female opposite threads, thus the wire may be evenly contracted or released on both ends. On the outside, the thread nut 44 is formed as hexagon, thus it may be easily be rotated using a respective wrench for adjusting the pretension force. In said embodiment, the brake ring 20 comprises a peripheral recess in order to axially fix the wire. The wire may for example comprise a thickness of 5 mm to 9 mm.

LIST OF REFERENCE NUMBERS

[0063] 10 Bearing assembly

[0064] 12 Bearing element

[0065] 14 Longitudinal axis

[0066] 16 Cover plate

[0067] 18 Brake device

[0068] 20 Brake ring

[0069] 22 Clamping collar

[0070] 24 Recess

[0071] 26 Outer peripheral surface

[0072] 28 Screw element

[0073] 30 Coupling device

[0074] 32 Coupling ring

[0075] 34 Portion

[0076] 36 Guiding pin

[0077] 38 Electromagnet

[0078] 40 Pressure spring

[0079] 42 Nut

[0080] 44 Threaded nut