Rotary brake and manufacturing process

Abstract

The invention relates to a rotational brake (10) for limiting a rotational speed. A first segment (11) is arranged between the second segment (15) and the third segment (16) and has at least one through-hole (13) open parallel to the axis of rotation (12), in which a ball (14) is guided perpendicular to the axis of rotation (12). The second and third segments (15, 16) each have an annular running surface (17) for the at least one ball (14), directed towards the at least one through-hole (13) of the first segment (11). The annular running surfaces (17) alternate between at least one uphill surface (18) and at least one downhill surface (19) at approach surfaces (20, 21) with respect to the axis of rotation (12).The mountain surfaces (18) and the valley surfaces (19) of the mutually aligned running surfaces (17) are offset from each other in such a way that the at least one ball (14) is displaced on the approach surfaces (20, 21) when the first segment (11) rotates relative to the second and third segments (15, 16), while the ball (14) is simultaneously guided in the through-hole (13) of the first segment (11) in a rotational movement about the axis of rotation (12).

Description

[0001] The present invention relates to a rotary brake and a method for its manufacture.

[0002] Rotary brakes are used, for example, in roller blinds, self-retracting cable or hose reels, or abseiling devices to prevent excessive acceleration, such as that caused by a spring mechanism. Rotary brakes also serve to limit rotational speed. They can also be referred to as safety brakes.

[0003] For example, US Patent 4,513,805 A discloses a rotary brake for roller blinds that incorporates a centrifugal brake. However, activating the centrifugal brake requires a high rotational speed, necessitating a gearbox. The gearbox increases the rotational speed to reduce overspeed by engaging the centrifugal brake. Such gearboxes require tight manufacturing tolerances and are complex to produce. Furthermore, redundancy or modularity is difficult to achieve with these types of gearboxes. Additionally, friction, and consequently heat input, occurs very locally in such a centrifugal brake, negatively impacting its durability.

[0004] DE 18 12 369 A discloses a continuously variable clutch transmission with the operating characteristics of a transmission, clutch, freewheel and brake for motor vehicles.

[0005] Furthermore, DE 10 2004 012 952 A1 shows a spring-operated parking brake device with an actuating unit and a transmission unit for transmitting an actuating force to a braking device.

[0006] The object of the present invention is to provide a rotary brake which is inexpensive to manufacture and overcomes the aforementioned disadvantages.

[0007] The object of the invention is achieved by the features of the independent claims. Further preferred developments can be found in the dependent claims.

[0008] A rotational brake for limiting a rotational speed is proposed, wherein the rotational brake comprises an axis of rotation, at least one sphere, at least one first, preferably outer, segment, at least one second, preferably upper inner, segment, and at least one third, preferably lower inner, segment. It is proposed that the first segment be arranged along the axis of rotation between the second and third segments and have at least one through-hole open parallel to the axis of rotation. The through-hole has a free cross-sectional area larger than the largest cross-sectional area of ​​the sphere and a depth smaller than the diameter of the sphere. The through-hole guides the sphere perpendicular to the axis of rotation.The second and third segments are connected to each other in a rotationally fixed manner about the axis of rotation and each has an annular running surface for the at least one ball, directed towards the at least one through-hole of the first segment and oriented about the axis of rotation, preferably concentric to the axis of rotation, wherein the two annular running surfaces are aligned with each other. The annular running surfaces alternate with respect to the axis of rotation and preferably along its course between at least one up surface and at least one down surface at at least two approach surfaces.The mountain surfaces and the valley surfaces of the respective mutually aligned running surfaces are offset from each other in such a way that, during a relative rotation of the first segment with respect to the second and third segments, at least one ball is displaced on the approach surfaces parallel to the axis of rotation, while at the same time the ball is guided in a rotational movement around the axis of rotation in the through-hole of the first segment.

[0009] A rotary brake allows for controlled braking of a rotating motion. The rotary brake is preferably a circumferential rotary brake.

[0010] The walls of the through-holes and the running surfaces, especially the approach surfaces, serve as friction surfaces against which the balls rub during relative movement of the first segment to the second and third segments. The approach surfaces ensure that, during relative movement of the first segment to the subsequent segments, the balls are pressed parallel to the axis of rotation, thus lifting them from a valley surface to a peak surface. The opposite running surface releases the corresponding area through a corresponding transition from peak to valley surface. By pressing the balls, which are guided in a rotationally fixed manner around the axis of rotation of the rotary brake in the first segment, against the walls of the through-holes and the approach surfaces during each transition between valley and peak surface, an advantageous braking effect is achieved through friction, which counteracts the relative movement in the rotary brake.

[0011] The second and third segments are preferably connected to each other in a rotationally fixed manner. For example, nine balls can be guided in the first segment. The friction and the resulting heat are distributed much more homogeneously across the rotary brake than, for example, in centrifugal brakes of the prior art. The through-holes in the first segment, each guiding a ball, can, for example, be arranged rotationally symmetrically around the axis of rotation.

[0012] A corresponding rotary brake does not rely on centrifugal force. Instead, it generates a braking effect using spheres as a mass. The braking force is preferably exponential to the rotational speed, since the spheres preferably reciprocate one or more times with each rotation. Furthermore, the required energy is preferably quadratic to the rotational speed.

[0013] The proposed rotary brake can be manufactured simply and cost-effectively. Preferably, the rotary brake can be attached to the outer circumference of the first segment and to the second and third segments in the region of the axis of rotation. The first segment, or the second and third segments, can be driven. Furthermore, adapting the size to the application is significantly easier than with prior art rotary brakes.

[0014] Preferably, the rotary brake has a number of balls guided in a first segment in respective through holes, each of which is greater than the number of mountain surfaces and the number of valley surfaces of the annular, mutually aligned running surfaces for these balls.

[0015] Preferably, the rotary brake comprises a number of balls guided in at least a first segment in respective through-holes, the number of which has no common divisor with the number of uphill and downhill surfaces of the annular, mutually aligned running surfaces for these balls. In this way, each ball is in a different state at any given time, particularly with respect to its position relative to the contact surface(s). This allows for a more uniform braking torque, thus reducing or eliminating pulsation of the braking torque. This is particularly advantageous if, in a preferred embodiment, the first segment has a plurality of through-holes in which balls are guided, the through-holes being arranged equidistantly on a circle, the circle preferably being concentric around the axis of rotation.

[0016] According to a further advantageous embodiment, the spacing between the through-holes of the first segment for the balls is of different sizes, which also reduces or eliminates pulsating braking behavior. This is particularly advantageous when the lengths of the peak and valley surfaces of the annular running surfaces are the same.

[0017] In an advantageous embodiment, the peak and valley surfaces of the annular running surfaces have the same length. The length of a surface refers to the length of the path traveled by the balls on that surface. Due to the rotation about the axis of rotation, the path is therefore preferably a circular segment. This allows for simplified assembly and replacement of segments, particularly in a stacked rotary brake. In an alternative advantageous embodiment, the peak and valley surfaces of the annular running surfaces have different lengths. This also reduces or prevents pulsation of the braking torque.

[0018] In an advantageous embodiment, the running surfaces each have four uphill and four downhill sections. This allows for good braking characteristics of the rotary brake.

[0019] Preferably, the up surfaces of a running surface lie in a common up plane perpendicular to the axis of rotation, and more preferably, the down surfaces of a running surface lie in a common down plane perpendicular to the axis of rotation. In alternative embodiments, the down surfaces and the up surfaces are not parallel to a plane perpendicular to the axis of rotation. Furthermore, in possible embodiments, the down surfaces and the up surfaces may not be planar.

[0020] Furthermore, the first segment preferably has nine through-holes, each guiding a ball. The rotational brake ensures a low failure rate due to the large number of balls connected in parallel. Additionally, the segmented design allows for easy replacement of wear parts. Preferably, the through-holes in the first segment are circular.

[0021] In a preferred embodiment, it is proposed that the distance between the two running surfaces parallel to the axis of rotation not be less than the diameter of the ball. This prevents the ball from jamming between the two opposing running surfaces. Furthermore, it is preferred that the distance between the two running surfaces parallel to the axis of rotation be a maximum of 105% of the diameter of the ball in order to minimize rattling of the ball(s) and to achieve good positioning of the ball in the through-hole.

[0022] Preferably, the contact surfaces in both directions of rotation are aligned at an angle other than zero, preferably at an angle greater than 15°, to the axis of rotation.

[0023] This ensures a force component on the sphere parallel to the axis of rotation during relative motion. Furthermore, the contact surfaces are preferably oriented at a non-zero angle, preferably an angle greater than 15°, to the mountain and valley surfaces in both directions of rotation.

[0024] Preferably, the contact surfaces have different angles to the axis of rotation and / or curvature profiles with respect to the two directions of rotation. This enables different braking characteristics in the two directions of rotation around the axis of rotation of the rotary brake.

[0025] In an advantageous further development, the rotary brake has a plurality of first segments which, together with further second and third segments, form a stacked rotary brake.

[0026] In this way, the braking effect can be significantly increased for the same diameter. Furthermore, this modular design allows for easy scalability for varying braking strengths. Preferably, the contact surfaces of the first segments of a stacked rotary brake are arranged one above the other, parallel to the axis of rotation. This enables a shorter design along the axis of rotation.

[0027] In an advantageous embodiment, the majority of the first segments are connected to one another by a clip connection. This enables the rapid assembly of a stacked rotary brake. The clip connection preferably binds the first segments against rotation about the axis of rotation and axially along the axis of rotation. The clip connections are preferably located outside the circumferential running surfaces, and more preferably on the outer circumference, of the rotary brake.

[0028] Preferably, the second and / or third segment each have a running surface parallel to the axis of rotation in both directions. This enables a stacked, multi-level arrangement in which balls are guided in a first segment, with only one segment having running surfaces on both sides needing to be placed between each of the first segments, thus reducing the overall height and the number of parts.

[0029] In a preferred embodiment, at least a second segment and a third segment are identical in construction, so that the cost and complexity of the rotary brake can be further reduced.

[0030] According to a further development, it is proposed that the running surfaces are open radially outwards with respect to the axis of rotation. In preferred embodiments, the running surfaces are enclosed by a radial circumferential wall of a first segment.

[0031] Furthermore, it is proposed that the at least one second segment and the at least one third segment preferably have a positive locking connection directly between the respective segments, which creates a rotationally fixed connection about the axis of rotation. The second and third segments can thus preferably be rotationally fixed to one another by stacking. This positive locking connection is preferably provided within the circumferential running surfaces.

[0032] Furthermore, to solve the problem of the invention, a method for manufacturing a rotary brake of the type described above is proposed, wherein at least one segment, preferably all segments, is / are manufactured using an additive manufacturing process.

[0033] The balls are preferably steel balls, for example stainless steel or V2A. Alternatively, the balls can also be made of plastic or rubber if particularly quiet operation is desired. Furthermore, the segments are preferably made of plastic, for example polyamide, especially PA12.

[0034] The invention is explained below with reference to preferred embodiments and the accompanying figures. Fig. 1 a rotary brake; Fig. 2 a rotary brake in an exploded view; Fig. 3 a segment of a rotary brake; Fig. 4 a first segment of a rotary brake with nine through holes; Fig. 5 a double-stacked rotary brake; and Fig. 6 A double-stacked rotary brake in an exploded view.

[0035] Fig. Figure 1 shows a rotary brake 10 for limiting the rotational speed. The rotary brake can be used, for example, in a spring-loaded roller blind to prevent overspeeding during free rolling. The rotation occurs around the axis of rotation 12, and the rotary brake 10 can be used as an internal or external runner. The rotary brake 10 has a first segment 11 in which, in this embodiment, nine balls 14 are arranged in nine through-holes 13. The balls 14 are held upwards by a second segment 15 and downwards by a third segment 16 in the rotary brake 10. The first segment 11 can be rotated with a brake relative to the second and third segments 15 and 16. The rotary brake 10 can be fixed, for example, on the outside of the first segment 11 and on the inside of the second and third segments 15 and 16 for use.

[0036] Fig. Figure 2 shows the rotation brake 10 of the Fig. Figure 1 shows an exploded view. The first segment 15 has round through-holes 13 open parallel to the axis of rotation 12 and arranged circumferentially around the axis of rotation 12. The through-holes 13 have a larger diameter and thus a larger free cross-sectional area than the maximum cross-sectional area of ​​the spheres 14. Accordingly, the spheres 14 are movable within the through-holes 13 parallel to the axis of rotation 12. A plate 27 of the first segment 11, in which the through-holes 13 are arranged circumferentially, has a thickness that is smaller than the diameter of the spheres 14. The spheres 14 therefore always protrude beyond at least one edge of the two edges of the through-holes 13. Furthermore, in this embodiment, the first segment 11 has a circumferential rim 25 as an outer boundary.Furthermore, the first segment 11 has a central opening 26 through which the second segment 15 can be connected to the third segment 16 in a rotationally fixed manner.

[0037] In the Fig. Figure 2 below shows the third segment 16, which has an annular running surface 17 for the balls 14 on its upper surface. The annular running surface 17 has several mountain surfaces 18 on a higher mountain level and several valley surfaces 19 on a lower valley level, four of each in this embodiment. The transitions between the mountain surfaces and the valley surfaces are formed by ramp surfaces 20, 21. The ramp surfaces 21 rise in the direction of rotation 22 on the upper running surface 17 of the third segment 16, while the ramp surfaces 20 rise in the opposite direction of rotation 23.

[0038] The second segment 15 has a corresponding downward-facing annular running surface 17, which has the same number of uplift surfaces 18 and downlift surfaces 19 as the running surface of the third segment 16. The uplift surfaces 18 and downlift surfaces 19 merge into each other at the approach surfaces 20, 21.

[0039] A meandering channel is formed between the two annular running surfaces 17 of the second and third segments 15, 16, through which the balls 14 can be moved during a relative movement of the first segment 11 to the other segments 15, 16. For this to occur, the balls 14 must move between the upper and lower parts (as depicted in this illustration). These moves, which move the balls 14 to a different plane perpendicular to the axis of rotation 12, are initiated by contact with a contact surface 20, 21. This creates friction between the balls 14, the respective contact surface 20, 21, and the surfaces of the through-holes 13 in the first segment 11, which increases with higher rotational speed. The balls 14 can be made of steel, for example. The segments 11, 15, 16 can be made of polyamide, for example.

[0040] In this advantageous embodiment, the rotary brake 10 has nine balls 14 guided in through holes 13 of the first segment 11. The running surfaces 17 of the second and third segments 15, 16 each have four up surfaces 18 and four down surfaces 19 in this advantageous embodiment. The number of balls 14, nine in this embodiment, therefore has no common divisor with the number of up surfaces 18 and the number of down surfaces 19, so that the balls 14 are each in a different state and a pulsating braking torque can be suppressed.

[0041] In this advantageous embodiment, the through holes 13 in the first segment 11 are arranged equidistantly on a circle concentric with the axis of rotation 12. Furthermore, in this advantageous embodiment, the mountain surfaces 18 and the valley surfaces 19 of the annular running surfaces 17 have the same length.

[0042] In alternative embodiments, for example, the mountain surfaces 18 and valley surfaces 19 of a running surface 17 can have different lengths, wherein the corresponding running surface 17 aligned with this running surface 17 has correspondingly corresponding lengths of the mountain surfaces 18 and valley surfaces 19.

[0043] Fig. Figure 3 shows a segment 15, 16 in a single view, which can be used as a second segment 15 and also as a third segment 16. The segment 15, 16 of the embodiment in the Fig. 3 has two ring-shaped running surfaces 17, each oriented in a direction parallel to the axis of rotation 12, in this illustration one running surface 17 facing upwards and one running surface 17 facing downwards. Such a segment 15, 16 reduces the number of different parts of the rotary brake 10.

[0044] Furthermore, segment 15, 16 of the Fig. 3 especially for a stacked rotary brake 10 with several first segments 11 in which balls 14 are guided. The proposed segment 15, 16 with running surfaces 17 on both sides can form both the third segment 16 for balls 14 arranged below and the second segment 15 for balls 14 arranged above, see also Fig. 5 and Fig. 6.

[0045] Fig. Figure 4 shows an advantageous embodiment of a first segment 11 in a single view. In this advantageous embodiment, the first segment 11 has a shape on its circumferential edge 24 that makes it possible to connect several first segments 11 one above the other along the axis of rotation 12 by means of a clip connection 24.

[0046] Fig. Figure 5 shows an embodiment of a stacked rotary brake 10 with two first segments 11, which are positively connected to each other by means of such a clip connection 24. In this embodiment, the rotary brake 10 has two rows of balls.

[0047] Fig. Figure 6 shows the double-stacked rotary brake 10 of the Fig. 5 in an exploded view. It can be seen here that the first two segments 11 are identical in this advantageous embodiment. Furthermore, the second segments 15 are also identical in construction to the third segments 16, with the middle segment 15, 16 being identical in construction as described in Figure 5. Fig. 3 forms both a second segment 15 and a third segment 16.

[0048] In other possible embodiments, the braking effect of the rotary brake 10 can be further increased in stages by adding a third or more stacking layers. The identical segments 11, 15, and 16 allow for very simple assembly and easy replacement in case of damage.

[0049] In advantageous embodiments, the contact surfaces 20, 21 of the first segments 11 of a stacked rotary brake 10 are arranged one above the other, parallel to the axis of rotation 12. This allows for a shorter and therefore more compact design along the axis of rotation 12.

[0050] Furthermore, the dimensions and materials can be adapted in possible embodiments to withstand higher braking loads. In this advantageous embodiment, segments 11, 15, and 16 are manufactured using an additive manufacturing process.

[0051] Furthermore, the braking effect can be preset by the design of the contact surfaces 20, 21, in particular by the angle to the axis of rotation 12. The transitions of the contact surfaces 20, 21 can, for example, be rounded to achieve improved smooth running.

[0052] Furthermore, the approach surfaces 20 and the approach surfaces 21 can be designed differently, for example, by having a different angle to the axis of rotation 12 or differently designed transitions and curvatures, in order to achieve a different characteristic curve of the rotary brake 10 in the directions of rotation 22, 23.

[0053] In further alternative embodiments, the mountain surfaces 18 and valley surfaces 19 of a running surface 17 can also have different lengths in a stacked rotary brake 10, wherein the corresponding running surface 17 aligned with this running surface 17 has correspondingly corresponding lengths of the mountain surfaces 18 and valley surfaces 19.

[0054] In advantageous embodiments, the approach surfaces 20, 21 of the first segments 11 of a stacked rotary brake 10 are arranged one above the other parallel to the axis of rotation 12, so that, due to the meandering course for the balls 14, a compact design in the axis of rotation 12 is possible without narrowing the passage for the balls 14.

Claims

[1] Rotation brake (10) for limiting a rotational speed, wherein the rotation brake (10) has a rotational axis (12), at least one sphere (14), at least one first segment (11), at least one second segment (15), and at least one third segment (16), characterized by , that the first segment (11) - is arranged along the axis of rotation (12) between the second segment (15) and the third segment (16), - has at least one through hole (13) open parallel to the axis of rotation (12), wherein the through hole (13) - has a free cross-sectional area that is larger than the largest cross-sectional area of ​​the sphere (14), - has a depth that is smaller than the diameter of the sphere (14), and - the sphere (14) leads perpendicularly to the axis of rotation (12), the second segment (15) and the third segment (16) - are connected to each other in a rotationally fixed manner about the axis of rotation (12), - each have an annular running surface (17) directed towards the at least one through hole (13) of the first segment (11) around the axis of rotation (12) for the at least one ball (14), wherein the two annular running surfaces (17) are aligned with each other, wherein - the ring-shaped running surfaces (17) alternate with respect to the axis of rotation (12) between at least one mountain surface (18) and at least one valley surface (19) at at least two approach surfaces (20, 21), and wherein - the mountain surfaces (18) and the valley surfaces (19) of the respective mutually aligned running surfaces (17) are offset from each other in such a way that the at least one ball (14) is displaced on the approach surfaces (20, 21) parallel to the axis of rotation (12) when the first segment (11) is rotated relative to the second and third segments (15, 16), while the ball (14) is simultaneously guided in the through hole (13) of the first segment (11) in a rotational movement about the axis of rotation (12). [2] Rotary brake according to claim (1) characterized by , that the distance between the two running surfaces (17) parallel to the axis of rotation (12) does not fall below the diameter of the sphere (14). [3] Rotary brake (10) according to any of the preceding claims, characterized by , that the approach surfaces (20, 21) are aligned at an angle other than zero to the axis of rotation (12). [4] Rotary brake (10) according to any of the preceding claims, characterized by, that the approach surfaces (20, 21) have different angles to the axis of rotation (12) and / or curvature profiles in relation to the two directions of rotation (22, 23). [5] Rotary brake (10) according to any of the preceding claims, characterized by , that the rotation brake (10) has a plurality of first segments (11) which together with further second and third segments (15, 16) form a stacked rotation brake (10). [6] Rotary brake (10) according to claim 5, characterized by , that the majority of the first segments (11) are connected to each other by a clip connection (24). [7] Rotary brake (10) according to any of the preceding claims, characterized by , that the second and / or the third segment (15, 16) each have a running surface (17) parallel to the axis of rotation (12) in both directions. [8] Rotary brake (10) according to claim 7, characterized by, that at least a second segment (15) and a third segment (16) are identical in construction. [9] Rotary brake (10) according to any one of the preceding claims, characterized by , that the running surfaces (17) are open radially outwards in relation to the axis of rotation (12). [10] Rotary brake (10) according to any one of the preceding claims, characterized by , that the rotation brake (10) has a number of balls (14) which are guided in at least a first segment (11) in respective through holes (13) which have no common divisor with the number of mountain surfaces (18) and no common divisor with the number of valley surfaces (19) of the annular, mutually aligned running surfaces (17) for these balls (14). [11] Rotary brake (10) according to any one of the preceding claims, characterized by , that the running surfaces (17) each have four mountain surfaces (18) and four valley surfaces (19). [12] Rotary brake (10) according to any of the preceding claims, characterized by , that the first segment (11) has nine through holes (13) into each of which a ball (14) is guided. [13] Rotary brake (10) according to any of the preceding claims, characterized by , that the mountain surfaces (18) and the valley surfaces (19) of the ring-shaped running surfaces (17) have different lengths. [14] Rotary brake (10) according to any of the preceding claims, characterized by , that the at least one second segment (15) and the at least one third segment (16) have a positive connection directly between the respective segments (15, 16) which causes a rotationally fixed connection about the axis of rotation (12). [15] Method for manufacturing a rotary brake (10) according to any one of the preceding claims, characterized by , that at least one segment (11, 15, 16) is manufactured using an additive manufacturing process.

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