Spindle drive for a louvered window or louvered flap with a spindle drive

Description

[0001] The invention relates to a spindle drive with the features of the preamble of claim 1. It also relates to a louvered window or a louvered flap with a spindle drive for moving louver elements.

[0002] Spindle drives are known in a wide variety of applications. They generally serve to convert a rotary drive movement into a linear movement. In addition to manual spindle drives, motor-driven spindle drives are also used, and such motor-driven spindle drives are the subject of the present invention. EP 0 552 464 A1 discloses a spindle lifting mechanism with a driveable threaded spindle and at least one nut traveling along the rotating threaded spindle, with means for fastening the components to be actuated by the spindle lifting mechanism, wherein at least a part of the outer surface of the nut is designed as a spherical surface and the nut is received by a nut housing of at least two parts, the inner wall of which corresponds to the spherical surface of the nut rests against it, and the nut housing has the means for fastening the components.

[0003] One application area of ​​particular interest to the applicant for such spindle drives lies in the movement of closing elements for windows and / or flaps, especially the louvered elements of louvered windows or louvered flaps. For such components, for example, louvered windows used in facades, which have two or more window louvers arranged in a frame and rotatable about parallel axes of rotation, spindle drives are regularly used to move a motor-driven sliding element. This sliding element is part of a gearbox to which the window louvers are coupled, in order to rotate them synchronously to open or close the window opening.

[0004] Especially since louvered windows are being built with increasingly larger dimensions, resulting in larger louvers with greater weight and a larger surface area exposed to wind loads, the forces and moments required by the spindle drives have increased compared to previous requirements. This leads to problems, particularly if the spindle drive—comprising a drive motor, a threaded spindle coupled to the drive motor for a rotating drive, and a spindle nut mounted on the threaded spindle that can be moved longitudinally by the spindle's rotation—is not manufactured with the utmost precision and tightest tolerances.Even small tolerance deviations lead to inaccurate running, so that when the lead screw is driven, the lead screw nut guided on it can experience transverse forces acting perpendicular to the longitudinal axis of the lead screw. These transverse forces, especially at higher drive torques, cause the lead screw nut to tilt, resulting in an uneven load distribution on the thread flanks and a tendency for the threads of the lead screw nut and the lead screw to jam or wedge. Additional drive force must then be applied to overcome these jamming forces and move the lead screw nut along the longitudinal direction of the lead screw.This reduces the efficiency of the spindle drive, may require spindle drives to be designed with higher power output than would be necessary without taking such efficiency loss into account, and results in increased wear of the components involved, especially the spindle nut and the threaded spindle, which reduces the overall service life of the spindle drive.

[0005] However, the problem described above does not only exist in connection with spindle drives for louver elements of louvered windows or louvered flaps, but generally always where spindle drives have to move particularly high loads and where transverse forces acting on the spindle nut cannot be excluded in the design of the spindle drive.

[0006] The object of the invention is to address the problem outlined above and to further develop a spindle drive in such a way that, despite any transverse forces occurring at the spindle nut, these do not lead to increased thread resistance, wedging, or jamming of the spindle nut on the threaded spindle. In particular, an improved spindle drive that solves this problem is to be provided. Further considerations of the invention also focus on improving a spindle nut for such a spindle drive and on an improved louvered window or louvered flap with a correspondingly improved spindle drive.

[0007] The problem formulated above is solved according to the invention by a spindle drive with the features of claim 1. Advantageous further developments and embodiments of such a spindle drive are specified in claims 2 to 6.

[0008] A spindle drive according to the invention, which is designed or can be designed in particular for the motor-driven movement of louver elements of louvered windows or louvered flaps, initially comprises - and this is consistent with spindle drives known per se - a drive motor and a threaded spindle which can be driven by rotation by this motor, as well as a spindle nut which engages with the threaded spindle and which can be displaced axially along the threaded spindle by rotation of the threaded spindle.

[0009] The special feature of the spindle drive according to the invention is the design of the spindle nut, which, according to the invention, is multi-part, in particular two-part, and comprises a screw nut part and a bearing part. The screw nut part has an internal thread for engaging an external thread of the threaded spindle, thus interacting directly with the threaded spindle and its external thread. The bearing part receives the screw nut part; the screw nut part is supported within the bearing part. The bearing part is provided with drive elements through which a driving force applied by the threaded spindle to the spindle nut can be transmitted to a driven element. These drive elements, which, for example, have the form of a groove or...A screw nut can be coupled to the bearing part of the spindle nut, which can have the shape of a bore, a retaining pin, or the like, thus allowing an element that is actually linearly movable and driven by the spindle drive to be coupled to the bearing part of the spindle nut. Furthermore, it is essential that the screw nut part is not rigidly and positionally fixed in the bearing part, but rather that these two parts are movable independently of each other and relative to each other in one degree of freedom. In other words, the screw nut part is mounted in the bearing part in such a way that it can perform a relative movement to the bearing part with a directional component of the movement perpendicular to a longitudinal axis of the internal thread.

[0010] The nut component is mounted in the bearing component in such a way that it transmits axial movement along the threaded spindle to the bearing component with virtually no play. Only a compensating movement with a component in a transverse direction to the longitudinal axis of the thread can occur between the nut component and the bearing component. This prevents transverse loads, forces, or moments acting on the bearing component from being transmitted to the nut component and thus avoids jamming or binding of the nut component's internal thread on the external thread of the threaded spindle, as described above. Instead, the transverse force causes a certain degree of evasive movement of the bearing component relative to the nut component. This movement, made possible by the relative mobility of these two components, compensates for and absorbs such a transverse force.

[0011] Thus, a spindle drive designed according to the invention no longer requires higher motor power to overcome the clamping forces between the internal thread of the screw nut and the external thread of the threaded spindle and to move the spindle nut when transverse forces are applied. Due to the reduced friction losses achieved with the invention when moving the spindle nut, the energy consumption of the spindle drive decreases, and its efficiency is increased. Therefore, a spindle drive or drive motor with lower power specifications can be used for a given application, if possible. Power supplies can also be used that transform the mains voltage down to a low-voltage safety level for the motor. These can generally be integrated into the drive or mounted externally. They are smaller and allow for a more cost-effective design overall.The required power supply cables, electronic / electromechanical components, and emergency power systems can also be smaller and therefore more cost-effective. Furthermore, wear, particularly on the internal thread of the spindle nut (here, the nut part) and the external thread of the threaded spindle, is reduced, thus extending the service life and durability of the spindle drive designed in this way.

[0012] The relative movement between the bearing part and the nut part can be achieved, as provided in one embodiment, by the nut part having a bearing surface on its outer surface, which is formed in at least one section as a spherical or cylindrical segment. Furthermore, in this embodiment, the nut part is mounted in a receptacle formed in the bearing part, and this receptacle has a receiving surface which, in at least one section, corresponds to the spherical or cylindrical segment of the bearing surface. The respective shapes of the surfaces—bearing surface and receiving surface—are designed such that the respective spherical or cylindrical segments of the bearing surface and receiving surface form a hinge.In this way, a relative and evasive movement, essentially following a rotation, can occur between the bearing part and the screw nut part when transverse loads occur.

[0013] In the embodiment described above, it can be provided, in particular, that the spherical or cylindrical segment of the bearing surface is formed on at least one axial end face of the nut part (viewed in the longitudinal direction of the thread) in a region that is located axially beyond the internal thread, in front of or behind the internal thread, in the longitudinal direction of the thread. This ensures that loads from the nut part are transferred to the bearing part (via the corresponding segment of the receiving surface, which also has an end face) entirely as compressive loads and not as tensile loads. This results in improved strength compared to if these loads were transferred entirely or even partially as tensile loads. This is particularly advantageous under impact loads and manifests itself, for example, inWhen used in a louvered window or louvered flap, the spindle drive also offers improved burglar resistance, as the louvers connected to the drive cannot be easily pried open. Furthermore, the installation space required for load transfer from the screw nut to the bearing is located along the longitudinal axis of the thread, typically along the length of the spindle drive or its housing, allowing for a narrow spindle drive design. This is particularly advantageous for concealed installations.In particular, a spherical or cylindrical section for load transfer can be formed on both opposite end faces of the screw nut part along the longitudinal axis of the thread, outside the overlap of the internal thread (in the axial direction of the longitudinal axis of the thread in front of and behind it), so that pressure transfer of the loads to be applied can take place in both directions of travel of the spindle nut.

[0014] In another design variant, it can be advantageous to provide axial stops for the nut part within the bearing component. Such axial stops serve, in particular, to ensure a largely backlash-free positioning of the nut part relative to the bearing component in a direction parallel to the longitudinal axis of the nut part's thread. This allows the linear drive generated by the interaction of the threaded spindle and the nut part to be transmitted directly and with virtually no backlash to the bearing component and, via the bearing component, to an element to be moved by the spindle drive.

[0015] It is advantageous to use an anti-rotation device to ensure that the nut portion cannot be rotated relative to the bearing portion about the longitudinal axis of the internal thread formed in the nut portion. This ensures that rotation of the threaded spindle also reliably leads to a longitudinal displacement of the spindle nut. Such an anti-rotation device can be designed in a variety of ways. In particular, it is achieved by a non-rotationally symmetrical cross-sectional shape of the nut portion in at least one section perpendicular to the longitudinal axis of the internal thread formed in the nut portion and a corresponding counter-shape in the bearing portion, whereby the anti-rotation device is also designed to prevent the desired compensating or deflecting movement between the nut portion and the bearing portion (a movement that essentially amounts to a tilting or...Rotation about an axis running transversely to the longitudinal axis of the thread is not hindered. This can be achieved, for example, in a screw nut part that is otherwise cylindrical in its longitudinal direction (i.e., the direction of extension of the longitudinal axis of the thread), by at least one, and in particular two, projections opposite each other transversely to the longitudinal axis of the thread, which form a partially cylindrical or spherical segment-shaped surface and, on two end faces located in the circumferential direction of the screw nut part, in particular flat stop surfaces, and which interact with corresponding counter-structures, e.g., formed as a recess or recesses in the bearing part. These counter-structures then in turn also have stops that interact with the stop surfaces to prevent a relative rotation of the screw nut part to the bearing part about the longitudinal axis of the thread. The recesses are, for example,rectangular in shape, so that they offer sufficient play to allow the evasive or compensatory movement described above.

[0016] The spindle drive according to the invention comprises a common drive housing in which the drive motor, the threaded spindle, and the spindle nut are arranged. For this purpose, the drive housing has a longitudinally elongated shape, with the threaded spindle then arranged extending along the longitudinal direction of the drive housing. According to the invention, guide structures are formed in the drive housing, in particular as guide surfaces, which interact with corresponding counter-structures on the bearing part of the spindle nut to guide the spindle nut in the longitudinal direction of the drive housing. Such guidance provides additional stability and improved functionality of the spindle drive according to the invention.

[0017] A further aspect of the invention can be seen in a louvered window or louvered flap, which comprises louvered elements arranged in a common frame in a conventional manner and rotatable about parallel axes of rotation, and a drive mechanism. This drive mechanism includes a push element connected to the louvered elements for converting a longitudinal movement into rotary movements of the louvered elements about their axes of rotation. The louvered window or louvered flap according to the invention is characterized in that it has a spindle drive of the type described above, which is coupled to the push element for driving the push element.

[0018] Further advantages and features of the invention will become apparent from the following description of an exemplary embodiment with reference to the accompanying figures. These show: Fig. 1 a three-dimensional view of an embodiment of a spindle drive according to the invention; Fig. 2 a longitudinal sectional view of the Fig. 1 The spindle drive shown; Fig. 3 is an enlarged view of a section from Fig. 2 , which allows a more detailed view of the threaded spindle and the spindle nut mounted on it; Fig. 4 a partially cut-out three-dimensional view of the in Fig. 3 shown section of the spindle drive; Fig. 5 an enlarged sectional view of the spindle nut sitting on the threaded spindle; Fig. 6 a view of the spindle nut with a partially cut-away bearing part to illustrate an anti-rotation device; and Fig. 7 a sectional view of the spindle nut along a line perpendicular to that shown in the illustration of the Fig. 5 selected cutting plane located in the cutting plane.

[0019] The figures show a possible embodiment of a spindle drive according to the invention, which in particular includes a spindle nut according to the invention and which can be used in a louvered window or a louvered flap to drive the movement of the louver elements (window louvers or flap louvers) in a manner according to the invention. The figures are not to be understood as complete construction drawings and are not to scale. Rather, they represent schematic diagrams that, however, depict the essential elements of the invention in greater detail.

[0020] In the figures, a spindle drive according to the invention, in the embodiment shown therein, is designated by reference numeral 1. The spindle drive 1 has an elongated, tubular drive housing 2 with a rectangular cross-section, in which the elements essential for the operation and function of the spindle drive 1 are arranged. These essential elements are, in essence, a drive motor 3, a threaded spindle 4 connected to the drive motor 3 for its rotational drive, optionally via an intermediate gearbox, and a spindle nut 5 guided by an internal thread formed therein on an external thread of the threaded spindle 4. In this general design, the spindle drive 1 according to the invention corresponds to the basic design of conventional and known spindle drives, as used in many fields of application to convert a motor-generated rotary drive into a linear motion.

[0021] The special feature of the spindle drive 1 according to the invention is the design of the spindle nut 5. This is, like the Figures 3 to 7 can be seen, particularly in the enlarged illustrations according to Figures 5 to 7 The assembly is shown in two parts, consisting of a screw nut part 6 and a bearing part 7 in which the screw nut part 6 is mounted. The screw nut part 6 has the actual internal thread for interaction with the external thread of the threaded spindle 4 (in the Figures 3 to 5 Only the section of the threaded spindle 4 on which the nut part 6 sits is shown with the external thread; however, the external thread also extends beyond this and over essentially the entire length of the threaded spindle 4).

[0022] The bearing part 7 has a connection point for attaching to an element that is moved linearly by the spindle nut 5. This connection point is formed by a recess 8 in the bearing part 7, into which a cam-like detent projection formed on the moving element can be inserted and held in a positive-locking position for longitudinal movement. The bearing part 7 is designed such that its outer cross-section corresponds approximately to the inner cross-section of the drive housing 7, so that the bearing part 7 is guided by the drive housing 2. This is evident in the Figures 2 to 4In particular, the drive housing 2 has a slot 9 extending longitudinally along a section of the drive housing 2, through which the previously described connection of a moving element can be guided and secured in the recess 8 in the bearing part 7. The moving element, thus connected to the bearing part 7 of the spindle nut 5, can then be driven along the length of the slot 9 by the spindle drive 1.

[0023] How especially the Figure 5 as can be seen, but also from the Figures 6 and 7As can be seen, a receptacle 10 is formed in the bearing part 7, in which the screw nut part 6 is received. This receptacle 10 has, in particular, front and rear guide surfaces 11, which are formed on the inner side of a respective projection 12 facing the receptacle 10. The projections 12 extend in a direction transverse to a longitudinal axis of the threaded spindle 4. In this embodiment, the guide surfaces 11 are spherically segmented. However, they can also have a different shape, for example, cylindrical segments, as long as the shape of these surfaces allows for the movement described below.The screw nut part 6, which is received in the receptacle 10, rests with end faces 13 against the guide surfaces 11 of the receptacle 10. The end faces 13 have a corresponding shape to the guide surfaces 11 formed on the inner sections of the projections 12 facing the receptacle. In this embodiment, they are spherically segmented, but they can also be cylindrical segments if the guide surfaces 11 have such a shape, or they can assume another shape corresponding to the guide surfaces 11. The guide surfaces 11 are formed on the screw nut part 6 along the longitudinal axis of its internal thread at a front and rear end face and lie in this axial direction in front of and behind the section of the screw nut part 6 in which the internal thread is formed.This allows loads to be transferred from the screw nut part 6 to the bearing part 7 (via the end faces 13) in both axial directions of movement of the spindle nut under compression and not under tension.

[0024] It can also be seen that the bearing part 7, together with the screw nut part 6 held in the receptacle 10, has a certain amount of play in a direction transverse to the longitudinal axis of the threaded spindle 4 or transverse to the longitudinal axis of the internal thread in the screw nut part 6. This play, and the corresponding design of the guide surfaces 11 and end faces 13, which are formed as spherical (or cylindrical) segments or similarly as joint surfaces, as described above, results in the formation of a joint, similar to a pivot joint, about which the elements screw nut part 6 and bearing part 7, which are not rigidly connected to each other, can be moved relative to each other and thus moved in a direction transverse to the longitudinal axis of the internal thread in the screw nut part 6, in particular tilted or rotated about an axis transverse to the longitudinal axis of the thread. In the Figure 5A corresponding tilting motion is shown to illustrate this freedom of movement. In this way, a transverse moment or transverse load (i.e., a force acting in a direction perpendicular to the longitudinal axis of the internal thread of the screw nut part 6) transmitted via the element to be moved to the cut 8 in the bearing part 7 of the spindle nut 5 can be absorbed by inducing a compensating movement relative to the bearing part 7 and the screw nut part 6. This prevents a corresponding transverse load or load from being transmitted to the bearing part 7.a transverse moment leads to a wedging and jamming of the threads involved, namely the internal thread of the screw nut part 6 and the external thread of the threaded spindle 4, which would cause a clamping force that would have to be additionally overcome by the drive motor 3, which would thus lead to a higher power consumption of the drive motor, a lower efficiency and which would at the same time cause wear of the internal thread in the screw nut part 6 and the external thread of the threaded spindle 4.

[0025] At the same time, the projections 12 prevent relative movement between the bearing part 7 and the screw nut part 6 in a direction parallel to the longitudinal axis of the internal thread in the screw nut part 6 (and thus in the direction of the longitudinal extent of the threaded spindle 4), or restrict such movement to a minimally tolerable level. This ensures that the spindle drive 1 can move a linearly moving element without, or at least without relevant, longitudinal play, i.e., directly controlled.

[0026] In the Figures 6 and 7It can further be seen that the spindle nut 5 has an anti-rotation feature that prevents the nut part 6 from rotating relative to the bearing part 7 about the longitudinal axis of the internal thread of the nut part 6. This anti-rotation feature is formed by lateral projections 14 on the nut part 6. These projections extend lengthwise along a section of the nut part 6 along a circumferential direction of the otherwise cylindrical outer surface of the nut part 6 in this section, and widthwise along the longitudinal direction of the nut part 6, i.e., parallel to the longitudinal axis of the internal thread. In this embodiment, these projections 14 are located approximately in the middle of the longitudinal extent of the nut part 6. The projections 14 have a convexly curved contour along their width. This contour can, in particular, be cylindrical in shape.The projections 14 can also exhibit a curvature in their longitudinal direction – which is then also convex. In this respect, they can also be shaped in the form of a spherical segment. It is essential that the projections 14 form stop surfaces 15 at opposite longitudinal ends of their length.

[0027] The projections 14 are received in recesses 16 formed in the bearing part 7 when the spindle nut 5 is assembled. These recesses 16 have a substantially rectangular cross-section and also extend circumferentially around the receptacle 10. At their ends, as viewed along their length, the recesses 16 also have stop surfaces (not shown in detail here) which, when the screw nut part 6 is inserted into the bearing part 7, interact with the stop surfaces 15 to prevent rotation of the screw nut part 6 relative to the bearing part 7, preferably with substantially no play. Fig. 7As can be seen, the recesses 16 are wider in width than the projections 14. This, along with the convexly curved shape of the projections 14 in this direction, allows the nut part 6 to move away from the bearing part 7 without causing the nut part 6 to rotate with the threaded spindle 4, i.e., without a relative rotation of the nut part 6 to the bearing part 7. This is prevented by the corresponding stop surfaces.

[0028] The special design of the spindle nut 5 ensures that the spindle drive 1 maintains its smooth operation on the threaded spindle 4 even when transverse forces or loads act upon it (whether due to tolerance-related manufacturing deviations or particularly high loads), allowing the drive motor 3 to utilize its power optimally for the adjustment movement. Simultaneously, it is ensured that the nut portion 6 cannot rotate within the bearing portion 7 around the longitudinal axis of its internal thread relative to the bearing portion. List of reference symbols

[0029] 1 Spindle drive 2 Drive housing 3 Drive motor 4 Threaded spindle 5 Spindle nut 6 Screw nut part 7 Bearing part 8 Cut 9 Slot 10 Mount 11 Guide surface 12 Projection 13 End face 14 Projection 15 Stop surface 16 Recess

Claims

1. A spindle drive (1), in particular for the motor-driven movement of louvre elements of louvre windows or louvre shutters, having - a threaded spindle (4) which can be driven in rotation by a drive motor (3) and - a spindle nut (5) which engages with the threaded spindle (4) and can be displaced axially along the threaded spindle (4) by rotating the threaded spindle (4), wherein the spindle nut (5) is constructed in several parts, in particular in two parts, with a screw nut part (6) having an internal thread for engaging an external thread of the threaded spindle (4) and a bearing part (7) in which the screw nut part (6) is mounted and which has a driver structure (8) for transmitting a driving force applied by the threaded spindle (4) to the spindle nut (5) to an element to be driven, wherein the screw nut part (6) is mounted in the bearing part (7) in such a way that it can execute a relative movement to the bearing part (7) with a directional portion of the movement transverse to a longitudinal thread axis of the internal thread, characterised by a common drive housing (2), in which the drive motor (3), the threaded spindle (4) and the spindle nut (5) are arranged, wherein the drive housing (2) has an elongated shape in a longitudinal direction, wherein the threaded spindle (4) is arranged extending in the longitudinal direction of the drive housing (2), and by guide structures formed in the drive housing (2), in particular guide surfaces, which co-operate with corresponding counter-structures on the bearing part (7) of the spindle nut (5) in order to guide the spindle nut (5) in the longitudinal direction of the drive housing (2).

2. A spindle drive (1) according to claim 1, characterised in that the screw nut part (6) has a bearing surface which is formed on an outer side of the screw nut part (6) and which is formed in the shape of a spherical or cylindrical section in at least one section (13), wherein the bearing surface is formed in the shape of a spherical or cylindrical section, whereas the screw nut part (6) is mounted in a receptacle (10) formed in the bearing part (7), wherein the receptacle (10) has a receiving surface which is formed in a spherical or cylindrical section shape in at least one section (11) corresponding to the section (13) of the bearing surface formed in a spherical or cylindrical section shape, so that the sections (11, 13) of the bearing surface and receiving surface formed in a spherical or cylindrical section shape in each case form a joint.

3. A spindle drive (1) according to claim 2, characterised in that the spherical or cylindrical section (13) of the bearing surface is formed on at least one axial end face of the screw nut part (6) as viewed in the longitudinal direction of the thread in a region which is located axially beyond the internal thread, in front of or behind the internal thread in the direction of the longitudinal direction of the thread.

4. A spindle drive (1) according to one of the preceding claims, characterised by axial stops (12) for the screw nut part (6) arranged in the bearing part (7).

5. A spindle drive (1) according to one of the preceding claims, characterised by an anti-rotation device (14, 15, 16) for preventing a relative rotation of the screw nut part (6) to the bearing part (7) about the longitudinal thread axis of the internal thread.

6. A louvre window or louvre flap with louvre elements arranged rotatably about parallel axes of rotation in a common frame and a drive gear having a drive element connected to the louvre elements for converting a longitudinal movement into rotary movements of the louvre element about their axes of rotation, characterised in that the louvre window or the louvre flap has a spindle drive (1) according to one of claims 1 to 5, which is coupled to the push element for driving the push element.