USE OF A BALL SCREW, AND ACTUATING DRIVE ASSEMBLY

Abstract

An actuating drive (2) including a ball screw drive (3) for activating a self-closing, linearly activated fitting (4) and a method of use are provided. While the opening of the fitting (4) with the actuating drive (2) takes place by an electric motor by the ball screw drive (3), a restoring movement is transmitted to the spindle (6) when closing the automatically closing fitting (4). The restoring movement, and thus also a closing movement of the fitting (4), can be at least indirectly decelerated by way of the ball screw drive (3), this being able to protect the fitting (4) and ultimately also the ball screw drive (3) and optionally further components connected to the fitting (4) and/or the ball screw drive (3) from damage, and facilitating a fail-safe function.

Claims

1. A method for activating a self-closing, linearly activated fitting (4) using a ball screw drive (3), the method comprising: driving a nut (5) of the ball screw drive (3) for opening the fitting (4) via an electric motor to transitorily move a spindle (6) of the ball screw drive (4) in an opening direction of the fitting (4) to open the fitting (4); for closing the fitting (4), transmitting a linear restoring movement to the spindle (6); at the end of the restoring movement, continuing to run the spindle and axially releasing the spindle from a connection to the fitting (4); and at least partially dissipating a restoring force that has been introduced into the spindle (6) by the restoring movement, in a direction of force, behind the ball screw drive (3) by an actuating drive (2) connected to the ball screw drive (3).

2. The method as claimed in claim 1, wherein the restoring movement is at least one of a relaxing movement which is imparted by a pressurized medium that is switched by the fitting (4), or the relaxing movement of a restoring unit (7) having at least one restoring element (8).

3. The use as claimed in claim 1, wherein the restoring force that has been introduced into the spindle (6) by the restoring movement, in the direction of force, is at least partially dissipated by the ball screw drive (3) by a brake (14, 15) of the actuating drive (2) connected to the ball screw drive (2).

4. An actuating drive assembly (1), comprising: an actuating drive (2); a ball screw drive (3) which is driven by the actuating drive (2), and having a linearly activated fitting (4), the ball screw drive (3) comprises a nut (5) and a spindle (6) which is at least indirectly connectable or connected to the fitting (4); the fitting (4) is openable by an opening movement of the spindle (6), which is driven by the actuating drive (2) and the nut (5), directed in an opening direction of the fitting (4); a restoring unit (7) configured to provide a restoring movement which acts on the spindle (6) in a closing direction of the fitting (4); a brake unit (13) including a centrifugal brake (15); and a releasable interface (18) is openable during at least one of closing or opening the fitting (4) is configured between the ball screw drive (3) and the restoring unit (7).

5. The actuating drive assembly (1) as claimed in claim 4, wherein the restoring unit (7) has at least one restoring element (8), and the restoring movement is a restoring movement or relaxing movement of the at least one restoring element (8).

6. The actuating drive assembly (1) as claimed in claim 4, wherein at least one of a) the restoring unit (8) and the actuating drive (2) are integrated in a fail-safe unit (10), or b) the actuating drive assembly (1) has at least one of terminal detents or terminal switches for the fitting (4).

7. The actuating drive assembly (1) as claimed in claim 4, further comprising, a rotary encoder (11) for detecting terminal positions of the fitting (4), the rotary encoder (11) is configured for at least indirectly ascertaining a rotating movement of the nut (5) and for converting said rotating movement into a linear movement acting on at least one of terminal detents or terminal switches.

8. The actuating drive assembly (1) as claimed in claim 4, wherein the nut (5) of the ball screw drive (3) is mounted by at least one axial bearing (12) that is configured to absorb axial forces that are transmitted to the spindle (6) by the restoring movement.

9. The actuating drive assembly (1) as claimed in claim 4, wherein the spindle has a thread pitch of 16 millimeters.

10. The actuating drive assembly (1) as claimed in claim 4, wherein the brake unit (13) comprises an operating current brake (14).

11. The actuating drive assembly (1) as claimed in claim 4, further comprising a gearbox disposed between a drive motor (9) of the actuating drive (2) and the ball screw drive (4).

12. The actuating drive assembly (1) as claimed in claim 4, wherein the releasable interface (18) is configured between the ball screw drive (3) and the restoring unit (7), said releasable interface (18) being able to be opened when closing and/or opening the fitting (4), by tensile forces acting in at least one of the closing direction or the opening.

13. The actuating drive assembly (1) as claimed in claim 12, wherein the releasable interface (18) is configured for rotationally fixing the spindle (6), and the releasable interface (18) has a guide element (19) which couples a drive output of the restoring element (7) to the spindle (6).

14. The actuating drive assembly (1) as claimed in claim 4, further comprising a bush (22) which is rotationally fixed in a housing part (26) and prevents relative rotation between at least one of the spindle (6) and the bush (22) or between the spindle (6) and the housing part (26).

15. The actuating drive assembly (1) as claimed in claim 4, wherein an axial stroke of the fitting (4) between the open position thereof and the closed position thereof is dimensioned such that balls (20) of the ball screw drive (3) cannot perform a complete recirculation in the ball screw drive (3).

16. The actuating drive assembly (1) as claimed in claim 4, wherein said releasable interface (18) is configured for transmitting compressive forces in the closing direction and in the opening direction.

17. The actuating drive assembly (1) as claimed in claim 13, wherein the guide element (19) has axial play which is dimensioned so that the rotational fixing is maintained when opening and closing the fitting (4).

18. The actuating drive assembly (1) as claimed in claim 14, wherein the bush (22) is mounted so as to be at least one of axially displaceable in the housing part (26) or axially fixed to the spindle (6).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention will be described in more detail hereunder by means of exemplary embodiments, but is not limited to these exemplary embodiments. Further exemplary embodiments are derived by combining the features of individual or several claims with one another, and/or when combining individual or several features of the exemplary embodiment. In the figures, in some instances in a highly schematic illustration:

[0034] FIG. 1: shows a block diagram for visualizing a first embodiment of an actuating drive assembly having an actuating drive, a linear drive system having a ball screw drive, having a restoring unit and having a fitting, wherein the restoring unit and the actuating drive are integrated in a fail-safe unit;

[0035] FIG. 2: shows a block diagram for visualizing a further embodiment of an actuating drive assembly having an actuating drive, a linear drive system having a ball screw drive, having a restoring unit and having a fitting, wherein the restoring unit is configured as a separate module between the actuating drive and the fitting;

[0036] FIG. 3: shows a sectional illustration of a ball screw drive of an actuating drive assembly according to the invention; and

[0037] FIG. 4: shows a sectional illustration of a further embodiment of a ball screw drive of an actuating drive assembly according to the invention, wherein a spindle of the ball screw drive herein is rotationally secured by means of an internal toothing of a bush, the spindle running through the latter.

DETAILED DESCRIPTION

[0038] In the description hereunder of different embodiments of the invention, functionally equivalent elements have the same reference signs, even if said elements differ in design or shape.

[0039] The figures show at least parts of actuating drive assemblies which in their entirety are in each case identified by the reference sign 1.

[0040] Each of the actuating drive assemblies 1 shown comprises an actuating drive 2, a ball screw drive 3 driven by the actuating drive 2, and a linearly activated fitting 4.

[0041] The ball screw drive 3 comprises a nut 5 and a spindle 6 which is at least indirectly connected to the fitting 4.

[0042] The fitting 4 is able to be opened by means of an opening movement of the spindle 6 which is driven by way of the actuating drive 3 and the nut 5, said opening movement being directed in the opening direction of the fitting 4. The fitting 4 can be closed again by means of a restoring movement caused by a restoring unit 7 and acting on the spindle 6, said restoring movement acting in the closing direction of the fitting 4. The restoring unit 7 comprises at least one restoring element 8, for example a restoring spring. The restoring movement that acts on the spindle 6 when closing the fitting 4 here is a restoring movement and/or a relaxing movement of the restoring element 8 of the restoring unit 7.

[0043] The ball screw drive 3 is able to be driven by a drive motor 9 of the actuating drive 2. In the actuating drive assembly 1 shown in FIG. 1, the restoring unit 7 and the actuating drive 2 are integrated in a fail-safe unit 10. In the exemplary embodiment of an actuating drive assembly 1 shown in FIG. 2, a separate restoring unit 7 is used.

[0044] The actuating drive assembly 1, here the respective actuating drive 2, comprises terminal switches for the fitting 4. The terminal switches can define terminal positions of the fitting 4.

[0045] The actuating drives 2 of the actuating drive assemblies 1 shown in the figures have in each case a rotary encoder 11. The rotary encoders 11 are specified for detecting terminal positions of the respective fitting 4. With the aid of the rotary encoders 11 it is possible for a rotating movement of the respective nut 5 to be ascertained in the process and to mathematically convert said rotating movement to a linear movement acting on terminal detents.

[0046] FIG. 3 highlights that the nut 5 of the ball screw drive 3 shown there is also mounted by means of an axial bearing 12. The axial bearing 12 is disposed such that said axial bearing 12 is specified for absorbing axial forces that are transmitted to the spindle 6 by way of the restoring movement. In this way it is possible for comparatively high restoring forces to be transmitted from the spindle 6 to the nut 5.

[0047] The spindles 6 illustrated in FIGS. 3 and 4 have a thread pitch of 16 mm.

[0048] According to the two block diagrams of FIGS. 1 and 2, each of the actuating drives 2 shown comprises a brake unit 13. The brake units 13 comprise in each case an operating current brake 14 and a centrifugal brake 15.

[0049] Two gearboxes, specifically a worm gear 16 and a planetary gear 17, are provided between the drive motor 9 of the actuating drive 2 and the ball screw drive 3. The worm gear 16 as well as the planetary gear 17 are in each case not configured so as to be self-locking. The rotation of a drive output shaft of the drive motor 9 of the actuating drive 2 can be deflected by 90° with the aid of the worm gear 16. A reduction of the rotating speed introduced by way of the worm gear 16 into the planetary gear 17 is possible with the aid of the planetary gear 17. The rotating speed which for driving the spindle 6 is transmitted from the planetary gear 17 to the nut 5 of the ball screw drive 3 is thus lower than the rotating speed by way of which the drive output shaft of the drive motor 9 of the actuating drive 2 rotates. However, by means of the reduction provided by the planetary gear 17, in this instance a higher torque bears on the nut 5 such that not only can the fitting 3 be moved from the closed position thereof to the open position thereof but the restoring force of the restoring unit 7 can also be overcome by activating the spindle 6.

[0050] FIGS. 1 and 2 highlight that a releasable interface 18 is configured between the ball screw drive 3, specifically between the spindle 6 of the ball screw drive 3, and the restoring unit 7. The releasable interface 18 can be opened when closing the fitting. The is performed by tensile forces that act on the interface 18, acting in each case in the closing direction and also in the opening direction. The releasable interface 18 between the spindle 6 and the restoring unit 7 can open in particular when the fitting 4 is closed and the spindle 6, by virtue of the mass inertia thereof and/or of the mass inertia of the drive motor 9, potentially overruns somewhat.

[0051] In order for the fitting 4 to be moved to the open position thereof with the aid of the spindle 6, and for the spindle 6 with the aid of the restoring unit 7 to be impinged with the aid of the restoring unit 7 during the self-acting closing of the fitting 4, and for the restoring movement of the restoring unit 7 to be transmitted to the spindle 6, the interface 18 is specified for transmitting compressive forces in the closing direction and in the opening direction.

[0052] In order to prevent that the spindle 6 under axial loading rotates relative to the nut 5 driving the spindle, the interface 18 is moreover also specified for rotationally fixing the spindle 6. For this purpose, the interface 18 has a guide element 19 which can be configured as a feather key, for example. The interface 18, with the aid of the guide element 19, is specified for coupling a drive output of the restoring unit 7 to the spindle 6. The guide element 19 here permits axial play which is of such a dimension that the rotational fixing of the spindle 6 is maintained when opening and closing the fitting 4. The rotational fixing of the spindle 6 is thus not canceled during the orderly operation of the fitting 4.

[0053] FIG. 4 shows an exemplary embodiment of an actuating drive assembly 1 in which a bush 22 is provided for rotationally fixing the spindle 6. The bush 22 is specified and provided for preventing relative rotation between the spindle 6 and the bush 22 and between the spindle 6 and the housing part 26. The bush 22 here is mounted so as to be axially displaceable in the housing part 26 and is simultaneously axially fixed to the spindle 6.

[0054] The bush 22 has an internal toothing 23 and an external toothing 24. The internal toothing 23 of the bush 22 engages with a corresponding external toothing 25 of the spindle 6. The corresponding toothings 23 and 25 reliably prevent the spindle 6 from rotating relative to the bush 22. The bush 22 is axially established on the spindle 6 and moves conjointly with the spindle 6 when the spindle 6 moves in and out within the housing part 26, the latter surrounding the spindle 6 and the bush 22.

[0055] An internal toothing 27 which is configured so as to correspond to the external toothing 24 of the bush 22 and engages with the external toothing 24 is configured in the housing part 26. The external toothing 24 of the bush 22 and the internal toothing 27 of the housing part 26 prevent the bush 22 from rotating within the housing part 26 but do permit an axial displacement of the bush 22 within the housing part 26.

[0056] The corresponding toothings 23 and 25 as well as 24 and 27 can also withstand comparatively high forces and provide a high rotational resistance across the entire axial adjustment range of the spindle 6.

[0057] According to FIGS. 3 and 4, a receptacle space 28 into which the spindle 6 can overrun without colliding with components of the actuating drive assembly 1 is in each case provided in the housing 29. Additionally or alternatively to the receptacle space 28, a damping element could also be used for damping an axial overrunning movement of the spindle 6 and for avoiding a collision between the spindle 6 and components of the actuating drive assembly 1.

[0058] An axial stroke of the fitting 4 between the open position thereof and the closed position thereof, and an axial stroke of the spindle 6 that is traveled by the spindle 6 in order to move the fitting 4 between the open position of the latter and the closing position of the latter, are of such a dimension that balls 20 of the ball screw drive 3 cannot perform a complete recirculation in the ball screw drive 3.

[0059] In the actuating drive assemblies 1 which are at least partially shown in FIGS. 1 to 3, the ball screw drives 3 are thus used for activating a self-closing, linearly activated fitting 4. It is provided here that a nut 5 of the ball screw drive 3 for opening the fitting 4 is driven by an electric motor, as a result thereof a spindle 6 of the ball screw drive 3 is moved in a translatory manner in the opening direction of the fitting 4, and the fitting 4 is opened as a result. For closing the fitting 4, a linear restoring movement, here a relaxing movement, is transmitted to the spindle 6. The restoring movement can be a relaxing movement which is imparted by a pressurized medium which is switched by the fitting 4. The restoring movement can also be a relaxing movement of the restoring unit 7, already mentioned above, of the previously described actuating drive assembly 1. To this end, the restoring unit 7 has at least one restoring element 8, as has likewise already been explained above.

[0060] A restoring force that has been introduced into the spindle 6 by the restoring movement can be at least partially dissipated behind the ball screw drive 3 and in part also by the ball screw drive 3. In the actuating drive assemblies 1 illustrated in FIGS. 1 and 2, the dissipation of the restoring force is performed by the brakes 14 and 15 of the brake units 13 of the actuating drive assemblies 1 illustrated.

[0061] At the end of the restoring movement the spindle 6 may overrun and be released from the fitting 4. In the exemplary embodiments of the actuating drive assemblies 1 shown in the figures, the release of the spindle 6 is performed at the interface 18, between the spindle 6 and the restoring unit 7.

[0062] FIGS. 1 and 2 show that the fitting is connected to a line 21, for example a pipeline. A medium, which is potentially pressurized and can be switched by the fitting 4, flows through the line 21. A flow through the line 21 is disabled in the closed position of the fitting 4. The line 21 is passable when the fitting 4 is opened by way of the ball screw drive 3.

[0063] According to FIG. 4, a distal end of the spindle 6 is surrounded by a wiper ring 25 which prevents ingress of dirt as a result of the movement of the spindle 6.

[0064] The invention is directed toward improvements in the technical field of actuating drives 2. Proposed to this end is, inter alia, the use of a ball screw drive 3 for activating a self-closing, linearly activated fitting 4. While the opening of the fitting 4 by means of an actuating drive 2 takes place by an electric motor by way of the ball screw drive 3, a restoring movement is transmitted to the spindle 6 and from the latter to the nut 5 of the ball screw drive 3 when closing the automatically closing fitting 4. The restoring movement, and thus also a closing movement of the fitting 4, can be decelerated by way of the ball screw drive 3, in particular by means of the centrifugal brake 15, this being able to protect the fitting 4 and ultimately also the ball screw drive 3 and moreover optionally further components of an actuating drive assembly 1 from damage, and moreover also being able to facilitate a fail-safe function.

LIST OF REFERENCE SIGNS

[0065] 1 Actuating drive assembly
2 Actuating drive
3 Ball screw drive

4 Fitting

5 Nut

6 Spindle

[0066] 7 Restoring unit
8 Restoring element
9 Drive motor
10 Fail-safe unit
11 Rotary encoder
12 Axial bearing
13 Brake unit
14 Operating current brake
15 Centrifugal brake
16 Worm gear
17 Planetary gear
18 Interface between 6 and 7
19 Guide element

20 Ball

21 Line

22 Bush

[0067] 23 Internal toothing of 22
24 External toothing of 22
25 External toothing of 6
26 Housing part
27 Internal toothing in 6
28 Receptacle space

29 Housing