Drive for a door or window sash

Abstract

Drive (10) for a sash of a door or window, comprising a housing (12), a piston (16) slidably guided in the housing (12) and acted upon by a spring unit (14), and an output shaft (20) rotatably mounted in the housing (12) and connected to the piston (16) via a rack and pinion drive (18), wherein the rack and pinion drive (18) comprises a non-circular pinion (22) connected to the output shaft (20), the teeth (24) of which mesh with a piston-side mating tooth (26), and wherein the effective lever arm length (R) of the pinion-side tooth (24) increases with increasing sash opening angle in an initial sash opening angle range of 0° up to a first predetermined sash opening angle, starting from a relatively higher or maximum effective lever arm length (R0) at the sash opening angle of 0°. decreases, characterized by this,that the effective lever arm length (R) of the pinion-side toothing (24) increases abruptly with increasing wing opening angle from a second predetermined wing opening angle, which is greater than or equal to the first predetermined wing opening angle and less than the maximum wing opening angle, wherein, to generate the abruptly increasing effective lever arm length (R) of the pinion-side toothing (24) or the associated pitch curve jump (48), at least one meshing tooth pair (28, 30) of the pinion-side and piston-side toothing (24, 26) is provided with pressure-side tooth flanks (28', 30') that are extended compared to the pressure-side tooth flanks of the remaining tooth pairs.

Description

[0001] The invention relates to a drive for a wing of a door, a window or the like, comprising a housing, a piston slidably guided in the housing and actuated by a spring unit, and an output shaft rotatably mounted in the housing and connected to the piston via a rack and pinion drive, according to the preamble of claim 1.

[0002] Such a drive could, in particular, be a door closer.

[0003] In a drive of the type mentioned above, the output shaft, and thus the pinion, is rotated when the wing is opened and closed. Via the non-circular rack and pinion drive, the piston is moved axially within the housing against the force of the spring unit, which typically includes a compression spring, when the wing is opened. The spring unit thus generates the opening and closing torque of the drive or door closer.

[0004] In order to meet the increasingly stringent requirements for accessibility when entering doors, a door opening torque, and thus of the drive, that drops sharply as the door opens is required.

[0005] Door closers with a rack and pinion drive typically achieve only very slow opening torques, which do not meet the aforementioned accessibility requirements. In some cases, the opening torques even increase as the door opens. Therefore, additional components are necessary to generate a sufficient torque drop.

[0006] While the required torque drop can be achieved relatively easily by using a cam-driven mechanism in the door closer, these door closers are more complex in design and therefore more expensive than door closers with a rack and pinion drive. Furthermore, their efficiency and damping performance are often inferior to those of door closers with a rack and pinion drive.

[0007] Door closers with a scissor linkage as the power transmission device between the output shaft and the door leaf or frame inherently have a high decreasing opening torque due to the significant gear reduction of the linkage when the door leaf is opened. This allows for virtually any design of the gearbox within the door closer. With a power transmission device using a lever or a sliding arm guided in a guide rail, the gear reduction does not decrease as sharply, requiring the gearbox in the door closer to have a higher gear reduction to achieve a decreasing opening torque. To meet increasing demands for comfort and accessibility, door closers with a power transmission device comprising a sliding arm guided in a guide rail between the output shaft and the leaf are now almost exclusively designed with a cam-type drive, which provides a significantly decreasing gear ratio.A steep drop in the opening moment at the door allows for easy passage. This drop in the leverage ratio, or opening moment, is inherent to the design and occurs particularly with door closers that allow door opening angles up to 180°. However, this results in a lower closing moment, which, especially for exterior doors exposed to wind loads and the like, no longer guarantees reliable closing. Therefore, a moderate drop in the door moment would be preferable.

[0008] Furthermore, door closers with cam-driven mechanisms have significantly shorter piston strokes and require higher spring forces compared to door closers with rack and pinion mechanisms, as the effective lever arm in the mechanism is shorter. This results in poorer hydraulic damping characteristics and higher component stresses. Additionally, due to their design, cam-driven mechanisms exhibit higher lateral forces and frictional forces in the area of ​​the force-transmitting pistons than rack and pinion mechanisms, leading to increased wear, reduced component durability, and lower door closer efficiency. Moreover, door closers with cam-driven mechanisms are generally more complex in design and therefore more expensive than those with rack and pinion mechanisms.

[0009] Conventional door closers with rack and pinion drives produce a barely decreasing opening torque despite the non-circular rack and pinion gears. DE 36 38 353 A1 and DE 93 19 547 U1 describe door closers with a rack and pinion drive featuring non-circular teeth, in which the effective lever arm of the drive shortens up to a predetermined door opening angle to generate a decreasing opening torque. However, the gear ratio of these known rack and pinion drives does not decrease sufficiently in the initial opening range to allow for a drop in opening torque comparable to that of cam-type drives. In an initial sash opening angle range, the effective lever arm only shortens to approximately 65% ​​of the initial value at a 0° sash opening angle. As the door opens further, the effective lever arm remains almost constant at large door opening angles or even shortens further.

[0010] For a significant drop in opening torque, a very low spring rate for the compression spring would be required. However, this would result in insufficient closing torque at large door opening angles due to the short effective lever arm of the gearbox and the low spring force. To generate a sufficient closing torque at large door opening angles, a high spring rate must be selected. The opening torque at the door is thus determined by the gear ratio of the power transmission device between the output shaft and the door leaf or frame, and the output torque of the door closer at the pinion gear, which is the product of the effective lever arm of the gearbox and the spring force.The spring rate of the compression spring must be chosen high enough so that the increase in spring force is sufficient to compensate for the drop in the gear ratio of the power transmission device, thus generating sufficient closing torque even at large door opening angles to ensure the door closes securely. However, this means that when the door opens, the force of the compression spring increases more rapidly than the shortening effective lever arm of the non-circular gearing can compensate for. The decrease in the gear ratio across the pinion's rotation angle is too small, resulting in only a minimal drop in the opening torque. For adequate accessibility, the gear ratio drop in the transmission would need to be higher.

[0011] DE 44 44 131 A1 describes a door closer according to the preamble of claim 1, comprising a rack and pinion drive with non-circular teeth, designed to generate a decreasing opening torque. For this purpose, the pinion has a specially shaped first tooth, the surface of which lies between the tooth head and the pressure-side tooth flank, engages with the tooth root of the mating teeth on the piston. A comparable door closer is disclosed in DE 44 44 132 A1.

[0012] Since the main reduction in the effective lever arm length of the transmission occurs through the rolling of the first to the second pair of teeth engaging when the door is opened, the height difference between the first and second teeth on the piston must be very large to allow for a decreasing opening torque similar to that of cam-driven transmissions. However, this is not feasible with the known design because the large height difference between the first two teeth on the piston results in excessively large engagement angles of the pinion in the piston teeth at the transition point from the first to the next tooth. This would, in the worst case, lead to self-locking or jamming of the system when the door is closed, or at least a significant drop in efficiency and wear. With the known design, the effective lever arm is only reduced to approximately...64% of the initial value at a 0° wing opening angle. Furthermore, the longer tooth, due to its extended shape and the contact area at the tooth head, is subjected to very high bending stresses, which impair the robustness of the system.

[0013] The contact area in the tooth head on the pinion is typically represented by a rounded surface, which, due to geometric constraints, is very small. This results in extreme surface pressures that can quickly lead to damage to the teeth. Therefore, the system is only suitable for door closers with low closing forces (lower spring forces), where a decreasing opening torque is no longer relevant, as the opening torques are already very low. Furthermore, the predominantly sliding teeth increase wear on the gear teeth.

[0014] Furthermore, due to its design, such a conventional system has relatively large pressure-side tooth flank angles (> 35° at a door opening angle of 0°) on the first tooth of the piston's toothing, which generate very high lateral forces that reduce the efficiency of the door closer, resulting in significantly increased opening torques of the door closer and also increased wear.

[0015] If the decreasing opening torques in door closers are achieved by gear ratios that decrease to a low value, then at a low ratio the movement of the damping piston in the door closer is also less, which leads to poorer damping properties.

[0016] Furthermore, in certain stop and / or mounting types, the translation of the force-transmitting linkage drops more sharply than in standard mounting, causing the already lower opening and closing torques to drop too much to still meet existing standards.

[0017] DE 10 2016 210 598 A1 discloses a drive for a wing of a door, a window or the like, which has means for energy conversion that interact with the piston, by which the mechanical kinetic energy of the piston can be converted into electrical energy and the electrical energy thus generated can be converted back into mechanical energy, in order in particular to supply at least one electrical component with electric current.

[0018] The invention is based on the objective of providing a drive or door closer of the type mentioned above, in which the aforementioned disadvantages are eliminated. The drive, equipped with a rack and pinion drive, should, in the simplest and correspondingly cost-effective design possible, exhibit in particular a decreasing opening torque that meets current accessibility requirements and improved opening damping properties, and be usable in all door stop types while complying with current standards. Furthermore, the drive should, in particular, also exhibit sufficient closing torque against wind loads and the like, even without special sliding rings on the piston, the highest possible efficiency, and high robustness against wear.

[0019] According to the invention, this problem is solved by a drive having the features of claim 1. Preferred embodiments of the drive according to the invention are described in the dependent claims, the present description, and the drawing.

[0020] The drive according to the invention for a leaf of a door, window or the like comprises a housing, a piston slidably guided in the housing and actuated by a spring unit, and an output shaft rotatably mounted in the housing and connected to the piston via a rack and pinion drive. The rack and pinion drive comprises a non-circular pinion connected to the output shaft, the teeth of which mesh with mating teeth on the piston side.In this process, the effective lever arm length of the pinion-side toothing decreases in an initial wing opening angle range of 0° up to a first predetermined wing opening angle, starting from a relatively higher or maximum effective lever arm length at the wing opening angle of 0° with increasing wing opening angle, while from a second predetermined wing opening angle, which is greater than or equal to the first predetermined wing opening angle and less than the maximum wing opening angle, it increases abruptly with increasing wing opening angle.

[0021] In the drive according to the invention, at least one meshing pair of teeth of the pinion-side and piston-side teeth with pressure-side tooth flanks that are extended compared to the pressure-side tooth flanks of the remaining tooth pairs is provided to generate the abruptly increasing effective lever arm length of the pinion-side toothing or the associated pitch curve jump.

[0022] The abrupt increase in opening and closing torque can thus be achieved by at least one specially shaped pair of teeth with extended pressure-side tooth flanks on the piston and pinion of the gearbox. The special shaping of the respective piston- and pinion-side teeth, realized through the relatively significantly extended pressure-side tooth flanks, results in a jump in the pitch curve or the effective lever arm of the gearing. Furthermore, the pressure-side tooth flank on the pinion side can have very large radii of curvature. The larger the radii of curvature of the tooth flank on a given pinion-side tooth, the more abruptly the effective lever arm increases when the pinion rotates. For example, with nearly linear radii of curvature (radius = ), the abrupt increase in the lever arm is maximal.

[0023] The abrupt increase in the effective lever arm length of the pinion-side gearing by at least 40%, preferably at least 60%, preferably occurs during the engagement of the at least one pair of teeth with extended pressure-side tooth flanks.

[0024] It is particularly advantageous if at least one pair of teeth of the pinion-side and piston-side gears engages with each other with extended pressure-side tooth flanks from a vane opening angle of around 60°.

[0025] In principle, the pitch curve jump realized by the at least one specially shaped pair of teeth of the rack and pinion drive can also occur at any other wing opening angle between the second specified wing opening angle and the maximum wing opening angle.

[0026] Preferably, each pair of teeth of the pinion-side and piston-side toothing, which engage with each other in the initial wing opening angle range, is designed such that when the wing opens, a line of action is obtained that runs horizontally, i.e. parallel to the displacement direction of the piston, or that rises relative to the horizontal or the displacement direction of the piston.

[0027] Due to this design, the drive, equipped with a rack and pinion drive, possesses a simple and correspondingly cost-effective construction, offering both a significantly reduced opening torque comparable to that of a cam-disc drive, thus meeting current accessibility requirements, and improved opening damping characteristics. Furthermore, the drive according to the invention can be used in all types of stops while complying with current standards. In addition, the drive according to the invention exhibits, in particular, sufficient closing torque against wind loads and the like, and, even without special sliding rings on the piston, the highest possible efficiency and high robustness against wear.While the opening torque of the drive can drop relatively sharply in an initial door opening angle range due to a gear ratio that decreases to a low value, the opening and closing torque increases sharply again from the second predefined sash opening angle onwards. Due to the correspondingly increased effective lever arm length of the pinion-side gearing, less back pressure is required to dampen the opening of the sash and decelerate the piston connected to the sash. Because of the lower back pressure, the material stresses on the drive are reduced, and the components also have to withstand lower pressures. Furthermore, the increased effective lever arm length increases the piston stroke, displacing more hydraulic fluid over a given sash opening angle range, thus also reducing the load on the flow control valves.The increased closing torque also compensates for the increased transmission drop of the force-transmitting linkage in certain stop or mounting types (e.g., mounting on the opposite side of the hinge, head or frame mounting, etc.), so that the drive meets the minimum closing torques of the existing standards in all stop or mounting types.

[0028] By designing each pair of teeth on the pinion and piston sides that engage with each other in the initial wing opening angle range such that a horizontal or rising line of engagement results when the wing opens, very small tooth flank angles can be achieved for the pressure-side tooth flank on the piston that first engages with the pinion-side teeth when the wing opens (in particular less than 25°, preferably less than 20°). This results in only low lateral forces being transmitted from the piston to the housing, thereby reducing friction. The reduced friction leads to high drive efficiency and simultaneously reduces wear, thus increasing the drive's service life.Due to the high efficiency, a significantly lower initial opening torque of the wing can be achieved with the same closing torque of the drive compared to door closers with a cam disc drive, thus increasing ease of use.

[0029] Preferably, the horizontal or rising course of the line of action of a respective pair of teeth engaging with each other in the initial wing opening angle range of the pinion-side and piston-side gearing is generated at least partially by a profile shift that varies accordingly when rolling over the pitch curve and / or a module that varies accordingly when rolling over the pitch curve and / or flank angles that vary accordingly when rolling over the pitch curve and / or radii of curvature of the tooth flanks of the pinion-side gearing that vary accordingly when rolling over the pitch curve.

[0030] Profile shift is a term from gear and transmission theory. In the design and manufacture of gears with a profile shift, the shape of the teeth is modified without altering the underlying base curve. In a gear with a profile shift, a different portion of the same curve (usually an involute or cycloid) is used as the tooth flank compared to a gear without a profile shift. The module is a measure of the size of the teeth of gears. It is defined as the quotient of the gear pitch (the distance between two adjacent teeth) and pi, a mathematical constant defined as the ratio of a circle's circumference to its diameter.

[0031] By ensuring that the teeth engaging with each other in the initial wing opening angle range, and in particular the first pair of teeth of the pinion-side and piston-side gears when the wing opens, have a horizontal or rising line of action due to varying profile displacement and / or varying module and / or varying flank angles and / or varying radii of curvature of the tooth flanks when the wing opens, a shorter engagement distance of the respective tooth pairs is partially achieved, which allows a rapid reduction in the effective lever arm length of the rack and pinion drive, so that when the wing opens further the wing the moment drops sharply, thus enabling more comfortable walking.Furthermore, a rising line of action, combined with the special design of the first pair of teeth featuring varying flank angles on the pinion and piston sides, enables advantageous engagement of the first pair of teeth at particularly small flank angles, thus reducing lateral forces and increasing efficiency. Due to the curved shape of the line of action, also known as the line of action, it could also be called a line of action. The point of contact between the flanks of the meshing teeth lies along the line of action. While the line of action initially dips slightly behind the pinion's centerline during tooth engagement, appropriate assembly ensures that effective tooth engagement only occurs from the pinion's centerline onward, where the line of action rises accordingly or runs horizontally.

[0032] Due to the inventive design of the toothing, the effective lever arm length of the pinion-rack drive and thus the gear ratio of the drive decreases sharply in the initial wing opening angle range with increasing wing opening angle (rolling curve rises extremely), whereby the opening torque drops very sharply, comparable to that of a cam disc drive, thus enabling comfortable, child-friendly and disabled-friendly access to the door.

[0033] According to a preferred practical embodiment of the drive according to the invention, the gear teeth of the rack and pinion drive are designed such that its gear ratio, starting from an initial value with the sash closed, decreases to at least 60%, preferably at least 55%, of the initial value up to a sash opening angle of 40°, preferably up to a sash opening angle of 30°. This results in a correspondingly steep decrease in the opening torque of the sash and, consequently, a high degree of accessibility. A sash opening angle of 30° corresponds, for example, to an axis angle of approximately 48°.

[0034] The first pressure-side tooth flank of the piston-side counter-toothing, which engages with the pinion-side toothing when the wing is opened, preferably has a tooth flank angle that is less than 25°, preferably less than 20°.

[0035] The initial wing opening angle preferably extends from 0° to a first predetermined wing opening angle in the range of 40°, preferably to a first predetermined wing opening angle in the range of 30°.

[0036] The effective lever arm length of the pinion-side toothing preferably increases abruptly from a second predetermined wing opening angle in the range of about 60° to about 65°, preferably from 60°, with increasing wing opening angle.

[0037] It is particularly advantageous if the effective lever arm length of the pinion-side gearing increases abruptly up to a sash opening angle of approximately 70°. In this case, the improved opening damping properties and increased closing torques are achieved within a sash opening angle range of approximately 70° and above.

[0038] The effective lever arm length of the pinion-side gearing can decrease further or at least remain essentially constant within the sash opening angle range between the first and second specified sash opening angles. The drive can therefore, for example, exhibit a low opening torque up to approximately 60°, while the opening and closing torque increases sharply from approximately 60° or at the latest 65°.

[0039] Preferably, the gearing of the rack and pinion drive is designed such that the pinion and piston can be driven in both directions. This ensures clean gear engagement even in cases of vandalism.

[0040] Preferably, at least one section of the pinion-side toothing with a decreasing effective lever arm length when the wing opens and one section of the pinion-side toothing with an increasing effective lever arm length when the wing opens are generated at least partially by a profile displacement that varies accordingly when rolling over the pitch curve and / or a module that varies accordingly when rolling over the pitch curve and / or flank angles that vary accordingly when rolling over the pitch curve and / or radii of curvature of the tooth flanks of the pinion-side toothing when rolling over the pitch curve.

[0041] In order to enable the lowest possible wear and the highest possible efficiency even at larger wing opening angles and higher spring forces, the pressure-side tooth flanks of the teeth of the piston-side mating teeth, which engage with the pinion-side teeth at wing opening angles in a range of approximately 60° up to the maximum wing opening angle of, in particular, 180° and especially in the range of the maximum wing opening angle, advantageously each have a tooth flank angle that is less than 20°, preferably less than 15°.

[0042] The piston is preferably designed as a hollow piston with internal teeth. In this case, the piston-side teeth are therefore located inside the piston.

[0043] The invention will be explained in more detail below with reference to an exemplary embodiment and the drawing; in this drawing: Fig. 1 a schematic representation of the basic structure of an exemplary embodiment of a drive according to the invention, Fig. 2 a schematic partial representation of the non-circular pinion rack and pinion drive of the drive according to Fig. 1 at a wing opening angle of 0°, Fig. 3 two schematic representations of the non-circular pinion rack and pinion drive of the drive according to Fig. 1 at a wing opening angle of 0° or a wing opening angle of 30°, Fig. 4 two schematic representations of the non-circular pinion rack and pinion drive of the drive according to Fig. 1 at a wing opening angle of 60° or a wing opening angle of 70°, Fig. 5 an enlarged representation of the tooth pair of the non-circular pinion rack and pinion drive of the drive, provided with extended pressure-side tooth flanks to generate the rolling curve jump according to Fig. 1 at a wing opening angle of 60°, Fig. 6 a schematic representation of the non-circular pinion rack and pinion drive of the drive according to Fig. 1, from which the effective lever arm length of the pinion-side gearing of the drive according to Fig. 1 is visible from a wing opening angle of 90°, and Fig. 7 a diagram showing the course of the opening and closing torque of the exemplary embodiment of the drive according to the invention, which depends on the wing opening angle. Fig. 1 with a sharply decreasing opening torque in an initial wing opening angle range and increased closing torques in the range from a wing opening angle of 70°, is compared to a drive with a conventional rack and pinion drive and to a conventional drive with a cam drive.

[0044] Fig. Figure 1 shows the basic structure of an exemplary embodiment of a drive 10 according to the invention for a door leaf, which in the present case is designed, for example, as a door closer. In the Fig. 2 to 6 is the non-circular pinion rack and pinion drive of drive 10 according to Fig. 1 shown at different wing opening angles.

[0045] As can be seen in particular from the Fig. As can be seen in Figure 1, the drive 10 comprises a housing 12, a piston 16 slidably guided in the housing 12 and acted upon by a spring unit 14, and an output shaft 20 rotatably mounted in the housing 12 and connected to the piston 16 via a rack and pinion drive 18. In this case, the spring unit 14 comprises, for example, a compression spring.

[0046] The pinion-rack transmission 18 comprises a non-circular pinion 22 connected to the output shaft 20, the teeth of which 24 mesh with a piston-side counter-tooth 26.

[0047] When the wing opens and closes, the output shaft 20 is rotated with the pinion 22, and the piston 16 in the housing is moved via the non-circular rack and pinion drive 18, whereby the spring unit 14 is tensioned when the wing opens and relaxes again when the wing closes. The spring unit 14 thus serves as a mechanical energy storage device for the drive 10.

[0048] The first pressure-side tooth flank 36 of the piston-side mating tooth 26, which engages with the pinion-side toothing 24 when the wing opens, has a tooth flank angle α that is less than 25°, preferably less than 20°. In the present embodiment, this tooth flank angle α is, for example, 21° (see Figure 1). Fig. 2).

[0049] As can be seen in particular from the Fig. As can be seen in Figure 3, the effective lever arm length R decreases in an initial wing opening angle range of 0° up to a first predetermined wing opening angle of, for example, 30°, starting from a relatively higher, in this case maximum, effective lever arm length R0 at the wing opening angle of 0° with increasing wing opening angle, while from a second predetermined wing opening angle, in this case for example from a second predetermined wing opening angle of 60° (see Figure 3). Fig. 4), increases abruptly. A respective pair of teeth 38, 40 of the pinion-side and piston-side teeth 24 and 26, respectively, which engage with each other in the initial wing opening angle range, is designed such that when the wing opens, a line of action 42 is formed which rises relative to the horizontal, i.e., the direction of displacement of the piston 16 (cf. Fig. 2).

[0050] During tooth engagement, the line of action 42 only rises from the center line 46 of the pinion 22, which runs through the center of the output shaft 20 and the first tooth 34 on the pinion side, while it may slope down slightly behind the center line 46. However, tooth engagement behind the center line 46 can be prevented by appropriate assembly.

[0051] The rising profile of the line of action 42 of a respective pair of teeth 38, 40 of the pinion-side and piston-side gears 24 and 26, respectively, which engage with each other in the initial wing opening angle range, can be generated at least partially by a profile shift and / or a module and / or flank angles and / or radii of curvature of the tooth flanks of the pinion-side gear 24 that vary accordingly when rolling over the pitch curve 44.

[0052] The rolling curve 44 (see especially Fig. 3) describes the force transmission points between the pinion-side and piston-side gears 24 and 26 respectively over the actuation cycle of the drive 10.

[0053] In the present embodiment, the initial wing opening angle range extends from 0° to a first predetermined wing opening angle in the range of 30°.

[0054] It is particularly advantageous if the teeth 24 of the rack and pinion drive 18 are designed such that its transmission decreases from an initial value with the wing closed, i.e. a wing opening angle of 0°, to at least a wing opening angle of 40°, preferably to at least a wing opening angle of 30°, to at least 60%, preferably to at least 55% of the initial value.

[0055] The effective lever arm length R of the pinion-side toothing 24 can increase abruptly, particularly from a second predetermined wing opening angle in the range of approximately 60° to approximately 65°, with increasing wing opening angle, whereby in the present case, for example, it increases abruptly from a second predetermined wing opening angle of 60° (see in particular Fig. 4a)). As particularly evident from Fig. As can be seen in section 3b), the effective lever arm length R of the pinion-side toothing 24 can increase abruptly, for example, up to a sash opening angle of around 70°. The increased opening and closing torque caused by the abrupt increase in the effective lever arm length is therefore reached in the present case at a sash opening angle of 70°.

[0056] The effective lever arm length R of the pinion-side toothing 24 can decrease further or at least remain essentially the same in the opening angle range between the first specified wing opening angle in the range of, for example, 30° and the second specified wing opening angle in the range of, for example, about 60° to about 65°.

[0057] To generate the abruptly increasing effective lever arm length R of the pinion-side teeth 24 and the associated pitch curve jump 48, at least one meshing pair of teeth 28, 30 of the pinion-side and piston-side teeth 24 and 26, respectively, can be provided with pressure-side tooth flanks 28', 30' that are extended compared to the pressure-side tooth flanks of the remaining tooth pairs. In the present embodiment, only one such tooth pair 28, 30 with extended pressure-side tooth flanks 28', 30' is provided (see in particular the Fig. 4 and Fig. 5).

[0058] The effective lever arm length R of the pinion-side toothing 24 can increase by at least 40% due to its abrupt increase, whereby in the present embodiment it increases by at least 60% (see in particular the Fig. 4).

[0059] As particularly evident from the Fig. As can be seen in Figure 4, the abrupt increase in the effective lever arm length R of the pinion-side toothing 24 by at least 60% in the present case, for example, can occur during the engagement of the tooth pair 28, 30 with extended pressure-side tooth flanks 28', 30'. In the present case, the abrupt increase in the effective lever arm length R thus begins, for example, at the wing opening angle of 60° (see Figure 4). Fig. 4a); R = 100%) and ends, for example, at the wing opening angle range of 70° (see Fig. 4b); R = 160%). The effective lever arm length R thus increased by 60% during the abrupt rise between the vane opening angles of 60° and 70°. The tooth pair 28, 30 of the pinion-side and piston-side gears 24 and 26, respectively, with extended pressure-side tooth flanks 28', 30', can therefore engage with each other, particularly from a vane opening angle in the range of 60°.

[0060] Fig. Figure 5 shows the tooth pair 28, 30 of the non-circular pinion rack and pinion drive 18 with extended pressure-side tooth flanks 28', 30' in an enlarged view at the wing opening angle of 60°.

[0061] The pinion-rack drive 18 can also be designed such that the pinion 22 and the piston 16 can be driven in both directions.

[0062] In the various embodiments shown in the figures, at least one respective section of the pinion-side toothing 24 with a decreasing effective lever arm length R when the wing is opened, and one respective section of the pinion-side toothing 24 with an increasing effective lever arm length R when the wing is opened, can be generated at least partially by a profile displacement and / or a module and / or flank angles and / or radii of curvature of the tooth flanks of the pinion-side toothing 24 that vary accordingly when rolling over the pitch curve.

[0063] The pressure-side tooth flanks 32 of the teeth 34 of the piston-side mating teeth 26, which engage with the pinion-side toothing 24 at wing opening angles in a wing opening angle range of approximately 60° up to the maximum wing opening angle of, in particular, 180°, and especially in the region of the maximum wing opening angle, each have a tooth flank angle α that is less than 20°, preferably less than 15°, wherein this tooth flank angle α is, for example, 14° in the present embodiment (see in particular Fig. 4a)).

[0064] The piston 16 of the drive 10 can be designed as a hollow piston with internal teeth.

[0065] As from Fig. As can be seen in Figure 3, the effective lever arm length R of the pinion-side toothing 25 in the present embodiment decreases by 50% with increasing wing opening angle in the initial wing opening angle range of 0° up to the first predetermined wing opening angle of, for example, 30°. This decrease starts from the relatively longer lever arm length R0 at the wing opening angle of 0°, which here corresponds to the maximum effective lever arm length. The effective lever arm length R of the pinion-side toothing 25 at the wing opening angle of 30° therefore corresponds to 50% of the lever arm length at the wing opening angle of 0° (R0 = 100%).

[0066] Fig. Figure 7 shows a diagram in which the opening torque of a drive according to the invention, which depends on the wing opening angle FÖW, with a sharply decreasing opening torque in an initial wing opening angle range and increased closing torques in the range from a wing opening angle of 70° (curve a)), is contrasted with that of a drive with a conventional rack and pinion drive (curve b)) and a conventional drive with a cam disc drive (curve c)).

[0067] As can be seen in particular from the Fig. As can be seen in Figure 6, the effective lever arm length R of the pinion-side toothing 25 in the present embodiment corresponds to a constant 80% of the maximum effective lever arm length at a wing opening angle of 0° from a wing opening angle of 90°.

[0068] As can be seen from the diagram, the drive 10 or door closer according to the invention (see curve a)) has a drop in opening torque similar to that of cam disc drives, while simultaneously achieving a sufficient closing torque against wind loads, higher efficiency, high robustness against wear, improved opening damping properties, and increased closing torques in the range from a wing opening angle of 70° in order to generate a sufficient closing torque in all stop types. Reference symbol list 10 Drive 12 cases 14 spring unit 16 pistons 18-pinion rack and pinion gearbox 20 Output shaft 22 sprockets 24 pinion-side teeth 26 piston-side counter-gears 28 pinion-side tooth with extended pressure-side tooth flank 28' extended pressure-side tooth flank 30 piston-side tooth with extended pressure-side tooth flank 30' extended pressure-side tooth flank 32 pressure-side tooth flank 34 piston-side tooth 36 first pressure-side tooth flank 38 pinion-side tooth 40 piston-side tooth 42 Intervention line 44 Rolling curve 46 Center line 48 Rolling curve jump R effective lever arm length R0 relatively higher, maximum effective lever arm length

Claims

[1] Drive (10) for a sash of a door or window, comprising a housing (12), a piston (16) slidably guided in the housing (12) and acted upon by a spring unit (14), and an output shaft (20) rotatably mounted in the housing (12) and connected to the piston (16) via a rack and pinion drive (18), wherein the rack and pinion drive (18) comprises a non-circular pinion (22) connected to the output shaft (20), the teeth (24) of which mesh with a piston-side mating tooth (26), and wherein the effective lever arm length (R) of the pinion-side tooth (24) increases with increasing sash opening angle from a relatively higher or maximum effective lever arm length (R0) at the sash opening angle of 0° up to a first predetermined sash opening angle. wing opening angle decreases, characterized by, that the effective lever arm length (R) of the pinion-side toothing (24) increases abruptly with increasing wing opening angle from a second predetermined wing opening angle, which is greater than or equal to the first predetermined wing opening angle and less than the maximum wing opening angle, wherein, in order to generate the abruptly increasing effective lever arm length (R) of the pinion-side toothing (24) or the associated pitch curve jump (48), at least one meshing tooth pair (28, 30) of the pinion-side and piston-side toothing (24, 26) is provided with pressure-side tooth flanks (28', 30') that are extended compared to the pressure-side tooth flanks of the remaining tooth pairs. [2] Drive according to claim 1, characterized by, that each pair of teeth (38, 40) of the pinion-side and piston-side teeth (24, 26) engaging with each other in the initial wing opening angle range is designed such that when the wing opens, a line of action (42) is formed which runs horizontally, i.e. parallel to the direction of displacement of the piston (16) or which rises relative to the horizontal or the direction of displacement of the piston (16). [3] Drive according to claim 2, characterized by, that the horizontal or rising course of the line of action (42) of a respective pair of teeth (38, 40) engaging with each other in the initial wing opening angle range of the pinion-side and piston-side gears (24, 26) is generated at least partially by a profile shift and / or a module and / or flank angles and / or radii of curvature of the tooth flanks of the pinion-side gear (24) varying accordingly when rolling over the pitch curve (44) when rolling over the pitch curve (44) when rolling over the pitch curve (44) when rolling over the pitch curve when rolling over the pitch curve [4] Drive according to at least one of the preceding claims, characterized by, that the toothing (24) of the pinion-rack drive (18) is designed such that the effective lever arm length (R) of the pinion-side toothing (24) decreases from an initial value when the wing is opened to at least 60% of the initial value up to a wing opening angle of 40° at the latest. [5] Drive according to at least one of the preceding claims, characterized by , that the first pressure-side tooth flank (36) of the piston-side counter-toothing (26) which engages with the pinion-side toothing (24) when the wing is opened has a tooth flank angle (α) that is less than 25°. [6] Drive according to at least one of the preceding claims, characterized by , that the initial wing opening angle range extends from 0° up to a first predetermined wing opening angle of 40°. [7] Drive according to at least one of the preceding claims, characterized by, that the effective lever arm length (R) of the pinion-side toothing (24) increases abruptly from a second predetermined wing opening angle in the range of 60° to 65° with increasing wing opening angle. [8] Drive according to claim 7, characterized by , that the effective lever arm length (R) of the pinion-side toothing (24) increases abruptly up to a wing opening angle of 70°. [9] Drive according to at least one of the preceding claims, characterized by , that the effective lever arm length (R) of the pinion-side toothing (24) in the wing opening angle range between the first specified wing opening angle and the second specified wing opening angle decreases further or at least remains the same. [10] Drive according to at least one of the preceding claims, characterized by , that the effective lever arm length (R) of the pinion-side toothing (24) increases by at least 40% due to its abrupt increase. [11] Drive according to at least one of the preceding claims, characterized by , that the abrupt increase in the effective lever arm length (R) of the pinion-side toothing (24) occurs during the engagement of the at least one pair of teeth (28, 30) with extended pressure-side tooth flanks (28', 30'). [12] Drive according to at least one of the preceding claims, characterized by , that at least one pair of teeth (28, 30) of the pinion-side and piston-side teeth (24, 26) with extended pressure-side tooth flanks (28', 30') engages with each other from a vane opening angle of 60°. [13] Drive according to at least one of the preceding claims, characterized by, that at least one respective section of the pinion-side toothing (24) with decreasing effective lever arm length (R) when the wing is opened and one respective section of the pinion-side toothing (24) with increasing effective lever arm length (R) when the wing is opened are generated at least partially by a profile displacement varying when rolling over the pitch curve and / or a module varying when rolling over the pitch curve and / or flank angles varying when rolling over the pitch curve and / or radii of curvature of the tooth flanks of the pinion-side toothing (24) varying when rolling over the pitch curve. [14] Drive according to at least one of the preceding claims, characterized by , that the toothing (24, 26) of the pinion-rack drive (18) is designed such that the pinion (22) and the piston (16) can be driven in both directions. [15] Drive according to at least one of the preceding claims, characterized by, that the pressure-side tooth flanks (32) of the teeth (34) of the piston-side mating teeth (26) which engage with the pinion-side toothing (24) in a wing opening angle range of 60° up to the maximum wing opening angle each have a tooth flank angle (α) that is less than 20°. [16] Drive according to at least one of the preceding claims, characterized by , that the piston (16) is designed as a hollow piston with internal teeth.

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