阅读说明：本技术 用于门扇或窗扇的驱动器 (Drive for a door leaf or window sash ) 是由 B·韦尔纳 于 2019-05-30 设计创作，主要内容包括：用于门、窗或类似物的扇的驱动器,包括壳体、可移动地在壳体中被引导的、通过弹簧单元被加载的活塞和可转动地支承在壳体中的、经由小齿轮齿条传动装置与活塞连接的从动轴。小齿轮齿条传动装置包括与从动轴连接的非圆形的小齿轮,其齿部与活塞侧的配合齿部啮合。在此,活塞侧的齿部的相应的在0°直至预定的扇打开角度的初始扇打开角度范围中与小齿轮侧的齿部的配合齿啮合的齿的压力侧的齿面具有与相应的小齿轮侧的配合齿接合的第一接触区域,在打开扇时,相应的小齿轮侧的配合齿经由尤其通过凹部或缩回部在其齿根处产生的凸起与第一接触区域接合。(A drive for a door, window or similar leaf comprises a housing, a piston which is guided displaceably in the housing and is acted upon by a spring unit, and a driven shaft which is rotatably mounted in the housing and is connected to the piston via a pinion-and-rack gear. The pinion-and-rack gear comprises a non-circular pinion connected to the driven shaft, the toothing of which meshes with a mating toothing on the piston side. In this case, the pressure-side tooth flanks of the respective teeth of the piston-side teeth meshing with the mating teeth of the pinion-side teeth in the initial fan opening angle range of 0 ° up to the predetermined fan opening angle have a first contact region with which the respective pinion-side mating teeth engage, and the respective pinion-side mating teeth engage via a projection, which is produced in particular by a recess or a setback at their tooth root, when the fan is opened.)

1. Drive (10) for a door, window or similar leaf, comprising a housing (12), a piston (16) guided movably in the housing (12) and loaded by a spring unit (14), and a driven shaft (20) rotatably mounted in the housing (12) and connected to the piston (16) via a pinion-and-rack gear (18), wherein the pinion-and-rack gear (18) comprises a non-circular pinion (22) connected to the driven shaft (20), the teeth (24) of which engage with the mating teeth (26) of the piston side, and the pressure-side flanks of the teeth (34) of the piston-side teeth (26) which engage with the mating teeth (32) of the pinion-side teeth (24) in an initial leaf opening angle range of 0 ° up to a predetermined leaf opening angle have a first contact region (A) which engages with the corresponding mating teeth (32) of the pinion side, and when the fan is opened, the respective pinion-side mating tooth (32) engages with the first contact region (A) via a projection (40) produced in particular by a recess or a retraction (38) at the tooth root of the pinion-side mating tooth.

2. Device according to claim 1, characterized in that the initial fan opening angle range lies between a fan opening angle of 0 ° and a fan opening angle of less than 10 °, in particular between a fan opening angle of 0 ° and a fan opening angle of 4 °.

3. Driver according to claim 1 or 2, characterized in that the profile angle (α _A) of the first contact area (a) of the pressure-side flank of the respective piston-side tooth (34) is <25 °.

4. Drive according to at least one of the preceding claims, characterized in that the pressure-side tooth flanks of the respective teeth (34) of the piston-side teeth (26) which mesh with the mating teeth (32) of the pinion-side teeth (24) in the initial fan opening angle range have at least two contact regions (A, B) which in turn engage with the respective pinion-side mating teeth (32), wherein the first contact region (A) which first engages with the associated pinion-side mating teeth (32) when the fan is opened has, in particular continuously, a smaller tooth form angle (α _A) than the tooth form angle of the respective further contact region (B) which immediately engages with the associated pinion-side mating teeth (32), with which the respective pinion-side mating teeth (32) engage via their projections (40).

5. drive according to claim 4, characterized in that the respective pairs (32, 34) of teeth of the pinion-side and piston-side teeth (24, 26) which engage one another in the initial fan-open angle range are designed such that a meshing line (42) arises which rises relative to the longitudinal direction of the piston-side teeth (26) provided as straight-toothed teeth or relative to the direction of movement of the piston (16) is produced, wherein, in particular in the initial fan-open angle range, starting from a relatively high effective lever arm length of the pinion-side teeth (24) at a fan-open angle of 0 °, the effective lever arm length of the pinion-side teeth (24) decreases with increasing fan-open angle.

6. Drive according to claim 5, characterized in that the rising course of the meshing line (42) of the respective pairs of teeth (32, 34) of the pinion-side and piston-side toothing (24, 26) which engage with one another in the initial fan opening angle range is respectively produced at least in part by a modified pinion-side and piston-side tooth profile when rolling on a rolling curve and/or by a modified tooth profile angle on the respective tooth (32, 34) when rolling on a rolling curve and/or a correspondingly modified radius of curvature of the tooth flank when rolling on a rolling curve.

7. Drive according to at least one of the preceding claims, characterized in that the projection (40) of the respective pinion-side mating tooth (32) projects only to such an extent that it engages with the first contact region (A) of the pressure-side tooth flank of the respective piston-side tooth (34) in the initial fan-open angle range.

8. Drive according to at least one of the preceding claims, characterized in that the first mating face (A ') of the pressure-side tooth face of the respective pinion-side mating tooth (32) with the first contact region (A) of the projection (40) that engages with the pressure-side tooth face of the respective piston-side tooth (34) follows the further mating face (B') of the pinion-side tooth (32) that engages with the further contact region (B) of the pressure-side tooth face of the piston-side tooth (34).

9. Drive according to at least one of the preceding claims, characterized in that the first contact region (A) and/or the further contact region (B) of the pressure-side flank of the respective piston-side tooth (34) are at least partially formed by an at least substantially flat surface.

10. Drive according to at least one of the preceding claims, characterized in that the further mating surface (B') of the pressure-side flank of the pinion-side tooth (32) which engages with the further contact region (B) of the pressure-side flank of the piston-side tooth (34) is at least partially formed by an at least substantially planar surface.

11. Drive according to one of the preceding claims, which is designed such that with it, with increasing fan opening angle, the further mating surface (B') of the pressure-side flank of the respective pinion-side tooth (32) slides onto the further contact region (B) of the pressure-side flank of the respective piston-side tooth (34), which sliding produces a planar abutment.

12. Drive according to at least one of the preceding claims, characterized in that the first contact region (A) and the further contact region (B) of the pressure-side flank of the respective piston-side tooth (34) are separated from one another by a discontinuous transition.

13. Drive according to one of claims 1 to 11, characterized in that the first contact region (a) and the further contact region (B) of the pressure-side flank of the respective piston-side tooth (34) transition into one another via an at least substantially continuous transition region.

14. Drive according to at least claim 13, characterized in that the first contact region (a) and the further contact region (B) of the pressure-side flanks of the respective piston-side tooth (34) transition into one another via a transition region with a rounded profile.

15. Driver according to claim 14, characterized in that the rounded contour of the continuous transition region between the first contact region (a) and the further contact region (B) of the pressure-side flank of the respective piston-side tooth (34) is formed by a determined radius, by a spline curve and/or the like.

16. Drive according to at least one of the preceding claims, characterized in that the first contact region (A) and/or the further contact region (B) of the pressure-side flank of the respective piston-side tooth (34) have at least partially a rounded contour and/or are formed by straight lines and arcs, spline curves and/or the like.

17. Drive according to at least one of the preceding claims, characterized in that the first mating surface (A ') and/or the further mating surface (B') of the pressure-side flank of the respective pinion-side tooth (32) have at least partially a rounded contour and/or are composed of straight and curved lines, spline curves and/or the like.

18. Drive according to at least one of the preceding claims, characterized in that the first contact region (A) and/or the further contact region (B) of the pressure-side flank of the respective piston-side tooth (34) respectively have at least partially a changing flank angle and/or the first mating face (A ') and/or the further mating face (B') of the pressure-side flank of the respective pinion-side tooth (32) respectively have at least partially a changing flank angle.

19. Drive according to at least one of the preceding claims, characterized in that the profile angle of a first contact region (A) of the pressure-side flank of the respective piston-side tooth (34) is smaller than the profile angle of the further contact region (B).

20. Drive according to at least one of the preceding claims, characterized in that the respective pairs (32, 34) of teeth (24, 26) of the pinion-side and piston-side teeth (24, 26) which engage one another in the initial fan-open angle range are designed such that a meshing line (42) which decreases relative to the longitudinal direction of the piston-side teeth (26) provided as spur-tooth teeth or relative to the direction of movement of the piston (16) results, wherein the effective lever arm length of the pinion-side teeth (24) remains at least substantially the same in the initial fan-open angle range or the effective lever arm length of the pinion-side teeth decreases from a fan-open angle of 0 ° with increasing fan-open angle up to preferably equal to or less than 60% of the initial value.

Technical Field

The invention relates to a drive for a door, window or similar leaf, comprising a housing, a piston which is guided displaceably in the housing and is acted upon by a spring unit, and a driven shaft which is rotatably mounted in the housing and is connected to the piston via a pinion-and-rack gear. The drive can be a door closer in particular.

background

In such drives, the piston is moved towards the spring unit, which usually comprises a pressure spring, when the fan is opened, so that the spring unit is tensioned. With the fan closed, the spring unit relaxes again. The spring unit thus acts as a mechanical energy store for the drive. In the case of a driven shaft connected to the piston via a pinion-and-rack gear, a transverse force acts on the piston as it moves against the spring force, due to the angle of inclination of the teeth or the tooth angle, which presses the piston against the housing. The frictional forces generated here deteriorate the efficiency of the drive and increase the wear.

In the initial fan opening angle range of, in particular, 0 ° to 4 °, a high closing torque is required in order to reliably close the door. At the same time, the opening torque should be as low as possible to achieve a gentle movement of the door. However, this now requires as high an efficiency as possible.

In the case of pinion-and-rack drives, for example so-called noncircular pinion-and-rack drives, in particular with noncircular pinions, the piston toothing is mostly designed as a straight toothing. The pinion toothing is derived from a rolling curve which describes the transition point between the pinion-side toothing and the piston-side toothing. In order to achieve a planar and robust positioning of the tooth flank of the pinion-side toothing on the piston-side toothing, a relatively large tooth flank angle α >25 ° is obtained, which is caused by design, precisely in the case of non-circular pinion-rack drives (in which the falling gate moment is achieved by shortening the effective lever arm of the pinion-side toothing during the initial opening range). The more significantly the effective lever arm of the tooth drops, the larger the tooth angle of the piston side becomes. However, very high transverse forces are now formed, which make the displacement of the piston in the longitudinal direction of the housing difficult and therefore adversely affect the efficiency. The meshing line determined by the rolling point of the teeth on the piston stroke is mostly designed to be lowered in the case of these conventional non-circular pinion-rack transmissions.

If a smaller tooth profile angle α is selected, the teeth of the pinion are not arranged on the tooth flanks, but rather on the edges or on the regions of the tooth tips with a smaller radius on the piston, as a result of which very high surface pressures are formed which can lead rapidly to damage and failure of the teeth. Furthermore, the resulting load direction and thus the frictional force in the transverse or y-direction remains unchanged. The tooth form angle α cannot then be easily varied at will.

Disclosure of Invention

The present invention is based on the object of providing a drive of the type mentioned in the introduction, in which the problems mentioned in the introduction are overcome. In this case, in the initial fan opening angle range from 0 ° to, in particular, 4 °, even when a falling fan or gate torque is achieved, in particular, by shortening the effective lever arm of the pinion-side toothing, the smallest possible tooth angle of the piston-side toothing is achieved and, in turn, the highest possible efficiency and the highest possible robustness and the lowest possible wear are ensured.

According to the invention, this object is achieved by a drive having the features of claim 1. Preferred embodiments of the drive according to the invention result from the dependent claims, the description and the drawings.

The drive according to the invention for a door, window or similar leaf comprises a housing, a piston guided displaceably in the housing and loaded by a spring unit, and a driven shaft rotatably mounted in the housing and connected to the piston via a pinion-and-rack gear. The pinion-and-rack gear comprises a non-circular pinion connected to the driven shaft, the toothing of which meshes with a mating toothing on the piston side. The teeth of the piston-side toothing, which mesh with the mating teeth of the pinion-side toothing in the initial fan opening angle range from 0 ° up to the predetermined fan opening angle, have a first contact region which engages with the corresponding pinion-side mating teeth, wherein the corresponding pinion-side mating teeth engage with the first contact region via a projection which is produced in particular by a recess or a setback at their tooth root when the fan is opened.

Based on this configuration, a very small tooth geometry angle of the piston-side toothing can be achieved and thus high efficiency, high robustness and low wear are ensured even in the case of a falling fan moment or door moment which is achieved in the initial fan-open angle range by shortening the effective lever arm of the pinion-side toothing. The special projection of the respective pinion-side mating tooth also effects a force transmission or force engagement even in the case of very small tooth flank angles of the piston-side toothing.

The initial fan opening angle range is preferably between a fan opening angle of 0 ° and a fan opening angle of less than 10 °, in particular 4 °.

Advantageously, the profile angle of the first contact region of the pressure-side tooth flank of the respective piston-side tooth is <25 °. Thus, the lateral forces acting on the piston are correspondingly minimized and correspondingly the efficiency and robustness are improved and wear is reduced.

According to a preferred practical embodiment of the drive according to the invention, the pressure-side flanks of the respective teeth of the piston-side teeth meshing with the mating teeth of the pinion-side teeth in the initial fan opening angle range have at least two contact regions which in turn engage with the respective pinion-side mating teeth, wherein a first contact region which first engages with the associated pinion-side mating teeth when the fan is opened (with which the respective pinion-side mating teeth engage with a projection) has, in particular continuously, a smaller tooth profile angle than the tooth profile angle of the respective further contact region which immediately engages with the associated pinion-side mating teeth.

By providing the first contact region with a relatively small profile angle, the transverse forces are correspondingly reduced, resulting in a correspondingly higher efficiency, a correspondingly higher robustness and a correspondingly lower wear.

It is particularly advantageous here if the respective pairs of teeth of the pinion-side and piston-side teeth which engage one another in the initial fan-open angle range are designed such that a meshing line which rises in relation to the longitudinal direction of the piston-side teeth provided as straight-toothed teeth or in relation to the direction of movement of the piston occurs, wherein the effective lever arm length of the pinion-side teeth decreases with increasing fan-open angle, in particular in the initial fan-open angle range, starting from the relatively high effective lever arm length of the pinion-side teeth at a fan-open angle of 0 °.

In this case, the rising course of the meshing line of the respective pairs of teeth of the pinion-side and piston-side toothing system which engage one another in the initial fan-open angle range is preferably produced at least in part by a modified pinion-side and piston-side tooth profile during rolling on the rolling curve and/or by a modified tooth profile angle on the respective tooth during rolling on the rolling curve and/or a modified curvature radius of the tooth flank during rolling on the rolling curve.

In some cases it is likewise advantageous if the projection of the respective pinion-side mating tooth is only so convex that it engages in the first contact region of the pressure-side tooth flank of the respective piston-side tooth in the initial fan-open angular range.

Preferably, the first mating surface of the pressure-side tooth surface of the respective pinion-side mating tooth, which has a convex shape and which engages with the first contact region of the pressure-side tooth surface of the respective piston-side tooth, is followed by the further mating surface of the pinion-side tooth, which engages with the further contact region of the pressure-side tooth surface of the piston-side tooth.

When the fan is opened, the first mating surface of the respective pinion-side tooth therefore first engages with the first contact region of the respective piston-side tooth, while the further mating surface of the pinion-side tooth only then engages with the further contact region of the pressure-side tooth.

The rising meshing line of the respective pairs of teeth, which is achieved at the respective teeth by the flank profile displacement and/or the changing flank angle and/or the changing radius of curvature of the tooth flanks of the small-and piston-side teeth, is furthermore achieved in that the further mating surfaces of the small-gear-side teeth slide on further opening of the fan onto the further contact regions of the pressure-side tooth flanks of the piston-side teeth, which have a larger flank angle.

The respective pinion-side tooth therefore does not rest on the edge during engagement, so that high surface pressures and wear are avoided. The efficiency is slightly reduced in this region due to the slightly higher transverse forces, which is however no longer so important in the case of larger gate angles. Furthermore, the piston is already in motion in this position, so that not the static coefficient of friction but a smaller sliding coefficient of friction comes into play in the case of friction.

According to an advantageous practical embodiment of the drive according to the invention, the first contact region and/or the further contact region of the pressure-side flank of the respective piston-side tooth is/are at least partially formed by an at least substantially planar surface. Alternatively or additionally, the further mating surface of the pressure-side flank of the pinion-side tooth which engages with the further contact region of the pressure-side flank of the piston-side tooth may also be formed, in particular, at least in part by an at least substantially flat surface.

This makes it possible to achieve an at least partially planar contact of the pressure-side flank of the respective pinion-side tooth on the pressure-side flank of the associated piston-side tooth.

Preferably, with increasing fan opening angle, the further contact surface of the pressure-side flank of the respective pinion-side tooth slides onto the further contact region of the pressure-side flank of the respective piston-side tooth, with which a planar contact is produced. Such a planar contact results in a low surface pressure, as a result of which the risk of wear is minimized. The efficiency in this region (in which the further mating surface of the respective pinion-side tooth engages with the further contact region of the respective piston-side tooth) is slightly reduced due to the higher transverse force, which is however no longer important in the case of a larger fan opening angle.

The first and the further contact region of the pressure-side flank of the respective piston-side tooth can be separated from each other by a discontinuous transition or can likewise be transitioned into each other via an at least substantially continuous transition.

In the latter case, the first contact region and the further contact region of the pressure-side flank of the respective piston-side tooth can advantageously merge into one another via a transition region with a rounded contour.

The rounded contour of the continuous transition region between the first contact region and the further contact region of the pressure-side flank of the respective piston-side tooth is formed by a defined radius, a spline curve and/or the like.

In some cases it is also advantageous if the first contact region and/or the further contact region of the pressure-side flank of the respective piston-side tooth have/has at least partially a rounded contour and/or are formed by straight lines and arcs, spline curves and/or the like.

Furthermore, the first mating surface and/or the further mating surface of the pressure-side flank of the respective pinion-side tooth can likewise have a rounded contour and/or be formed from straight lines and arcs, spline curves and/or the like.

According to an advantageous practical embodiment of the drive according to the invention, the first contact region and/or the further contact region of the pressure-side flank of the respective piston-side tooth accordingly has a varying profile angle at least in sections.

Alternatively or additionally, the first mating surface and/or the further mating surface of the pressure-side flank of the respective pinion-side tooth accordingly have at least partially a changing profile angle.

In this case, the tooth form angle of the first contact region is preferably smaller than the tooth form angle of the further contact region of the pressure-side tooth flank of the respective piston-side tooth. Thus, the first contact area continuously has a smaller profile angle than the further contact area.

In the initial fan-open angle range, the respective pairs of teeth of the pinion-side and piston-side teeth which engage one another in the initial fan-open angle range can likewise be designed such that a meshing line which decreases in relation to the longitudinal direction of the piston-side teeth provided as straight-toothed teeth or in relation to the direction of movement of the piston results, in the case of the effective lever arm length of the pinion-side teeth remaining at least substantially the same or decreasing with increasing fan-open angle starting from a fan-open angle of 0 ° up to preferably equal to or less than 60%, in particular equal to or less than 55%, of the initial value.

If, in the case of a pinion-and-rack gear, no or only a slightly decreasing sector moment is required by shortening the effective lever arm of the pinion, the meshing line of the respective pairs of teeth which engage one another in the initial sector opening angle range can then likewise be designed to be decreasing. In this case, too, the respective piston-side tooth is preferably again designed with a first contact region with a correspondingly smaller tooth flank angle, which first comes into contact with the projection of the respective pinion-side tooth when the fan is opened, in order to prevent the respective pinion-side tooth from bearing on the tooth tip of the piston.

Drawings

The invention is further illustrated below by means of an embodiment with reference to the accompanying drawings; wherein:

Figure 1 shows a schematic illustration of the basic structure of an exemplary embodiment of a drive,

Figures 2a) to d) show schematic representations of two teeth of a pinion-and-rack gear of a conventional drive meshing with each other in the case of different fan opening angles,

Figure 3 shows a schematic representation of two teeth of a pinion-and-rack gear of an exemplary embodiment of the drive according to the invention meshing with one another in the case of a fan opening angle of 0,

Figure 4 shows an enlarged schematic illustration of two teeth shown in figure 3 meshing with one another of the pinion-and-rack gear according to the invention which are relevant in the case of a fan opening angle of 0,

Figure 5 shows a schematic representation of two teeth of the pinion-and-rack gear according to the invention shown in figure 3 in relation to one another in the case of a door opening angle of 10,

Fig. 6 shows an enlarged schematic illustration of two teeth of the pinion-and-rack gear according to the invention shown in fig. 5, which engage in one another, in the case of a door opening angle of 10 °, and

Fig. 7 shows a schematic representation of two teeth of a pinion-and-rack gear of a further exemplary embodiment of the drive according to the invention meshing with one another in the case of a door opening angle of 3 °, wherein the projections of the respective pinion-side mating teeth project less strongly than in the case of the embodiments shown in fig. 3 to 6.

Detailed Description

Fig. 1 shows the basic structure of an exemplary embodiment of a drive 10 for a door, window or similar leaf.

The drive 10 comprises a housing 12, a piston 16 which is guided displaceably on the housing 12 and is acted upon by a spring unit 14, which in this case comprises a compression spring, for example, and a driven shaft 20 which is rotatably mounted in the housing 12 and is connected to the piston 16 via a pinion-and-rack gear 18. The pinion-and-rack gear 18 comprises a non-circular pinion 22 connected to a driven shaft 20, the toothing 24 of which meshes with a mating toothing 26 on the piston side. In this case, the actuator 10 is, for example, a door closer.

When the fan is opened, the piston 16 is moved towards the spring unit 14. Here, a transverse force acts on the piston 16 due to the angle of inclination or the tooth profile of the teeth of the pinion-and-rack gear 18, which presses the piston 16 against the housing 12. The frictional forces developed here can degrade the efficiency of the drive 10.

In particular, high closing torques are required in the initial fan opening angle range between 0 ° and 4 ° in order to close the fan or the door. At the same time, however, the opening torque should be as low as possible to achieve a gentle movement of the door, which requires a high degree of efficiency.

Only the first of the teeth of the toothing of the pinion-and-rack gear 18, which engage one another in the initial fan-open angle range of 0 ° to 4 °, is considered below.

fig. 2a) to d) show in schematic form two teeth of a pinion-and-rack gear of a conventional drive meshing with one another in the case of different fan opening angles.

Fig. 2a) shows a pinion-side tooth 30 which meshes with a piston-side tooth 28 in the case of a fan opening angle of 0 °, a force F _n directed perpendicularly to its pressure-side tooth flank is applied to the tooth 30 of the piston 16 by the tooth 30 of the pinion 22, which force, as shown by the depicted force parallelogram, splits into a force F _x directed in the longitudinal direction of the piston 16 and a transverse force F _y which presses the piston 16 against the housing 12 of the drive 10, as a result of which a frictional force which deteriorates the efficiency of the drive 10 is produced between the piston 16 and the housing 12 of the drive 10, the wear of the drive 10 likewise being increased on account of the higher frictional force.

In the illustration according to fig. 2b), a pinion-side tooth 30 is depicted, which, in the case of a fan opening angle of 4 °, bears flat against the pressure-side tooth flank of the piston-side tooth 28 at a correspondingly large tooth angle α.

In contrast, fig. 2c) shows a piston-side tooth 28 which engages with a pinion-side tooth 30, the pressure-side tooth flank of which has a smaller profile angle α, wherein the pinion-side tooth 30 no longer rests on the tooth flank, but on the edge of the tooth head of the piston-side tooth 28.

In the case of non-circular pinion-and-rack drives, the piston-side toothing is usually embodied as a straight toothing, the pinion-side toothing is derived from the rolling curve describing the point of force transmission between the pinion-side and piston-side toothing and the piston toothing, in particular in the case of non-circular pinion-and-rack drives, in which there is a gate moment which is reduced by shortening the effective lever arm of the pinion-side toothing in the range of the initial fan-open angle, in order to achieve planar and/or firm abutment of the tooth flanks of the pinion toothing on the piston toothing, relatively large tooth flank angles α >25 ° (see fig. 2a) and b) are derived by design, on the piston toothing, the effective lever arm length of the toothing decreases significantly, the tooth flank angle becomes greater, however, a very high transverse force F _y (see fig. 2a) is now produced, and a correspondingly high frictional force is formed between the piston 16 and the housing 12 of the drive 10, which makes the movement of the piston 16 in the x direction difficult and thus adversely affects the efficiency of the rolling point of the piston toothing in the conventional piston toothing (see fig. 2 c)).

In contrast, if a smaller tooth profile angle α of the pressure-side tooth flank of the piston-side tooth 28 (see fig. 2d)) is selected, the pinion-side tooth 22 no longer rests on the tooth flank of the piston-side tooth 28, but on the edge of the tooth head of this piston-side tooth 28, as a result of which very high surface pressures are formed, which quickly lead to damage and to wear or failure of the tooth system.

The profile angle α of the pressure-side tooth flank of the respective piston-side tooth 28 cannot then be easily varied at will.

Fig. 3 and 4 show two teeth 32, 34 of the pinion-and-rack gear 18 which mesh with one another in the exemplary embodiment of the drive 10 according to the invention in the case of a fan opening angle of 0 °. The basic structure of the drive can at least substantially correspond to the basic structure shown in fig. 1.

According to the invention, the pressure-side tooth flanks of the respective teeth 34 of the piston-side tooth system 26 which mesh with the mating teeth 32 of the pinion-side tooth system 24 in the initial fan-open angle range from 0 ° up to the predetermined fan-open angle have a first contact region a which engages with the respective pinion-side mating teeth 32. In this case, the respective pinion-side mating tooth 32 engages with the first contact region a via a projection 40, which is produced in particular by the recess or the retraction 38 at the tooth root thereof, when the fan is opened.

The initial fan opening angle range can in particular lie between a fan opening angle of 0 ° and a fan opening angle of less than 10 °, in particular 4 °.

Such a pinion-and-rack gear 18 according to the invention generates a very low transverse force F _y (see force parallelogram in fig. 3) and a correspondingly low frictional force between the piston 16 and the housing 12 (see also fig. 1) in the initial fan-out angle range of, in particular, 0 ° to 4 °, as a result of which, in particular in the case of a reduced door moment due to a shortening of the effective lever arm length of the pinion, a very low piston-side tooth angle and thus high efficiency, high robustness and low wear can be achieved in the initial fan-out angle range of, in particular, 0 ° to 4 °.

In the exemplary embodiment shown in fig. 3 to 7, the pressure-side tooth flanks of the respective teeth 34 of the piston-side tooth system 26 which mesh with the mating teeth 32 of the pinion-side tooth system 24 in the initial fan opening angle range have, for example, two contact regions a, B which engage in succession with the respective pinion-side mating teeth 32, the first contact region a which first engages with the associated pinion-side mating teeth 32 when the fan is opened (with which the respective pinion-side mating teeth 32 engage via their projections 40) has, in particular continuously, a smaller tooth profile angle α _A than the respective further contact region B which immediately engages with the associated pinion-side mating teeth 32.

As can be seen in particular from fig. 4 and 6, the first mating surface a 'of the pressure-side flank of the respective pinion-side mating tooth 32, which has the projection 40 and which engages with the first contact region a of the pressure-side flank of the respective piston-side tooth 34, can be followed by a further mating surface B' of the pinion-side tooth 32 which engages with the further contact region B of the pressure-side flank of the piston-side tooth 34.

In order to slide the engagement surface B' of the pressure-side flank of the respective pinion-side engagement tooth 32 onto the contact region B of the respective piston-side tooth 34 with the larger flank angle α _B when the door leaf is opened further, the respective tooth pair 32, 34 is designed such that a meshing line 42 (see in particular fig. 4 and 6) is obtained which rises in relation to the longitudinal direction of the piston-side tooth 26 provided as a straight-toothed tooth or to the direction of movement of the piston 16, the rising course of the meshing line 42 of the respective pairs of teeth 32, 34 of the pinion-side and piston-side teeth 24 or 26 which engage one another in the initial fan-open angle range is produced in each case at least in part by a displacement of the tooth profiles of the pinion-side and piston-side teeth which change when rolling on a rolling curve and/or by a tooth profile angle which changes when rolling on a rolling curve at the respective tooth 32, 34 and/or a curvature radius of the tooth flanks which changes when rolling on a rolling curve.

The respective pinion-side tooth 32 therefore does not rest on the crown during engagement with the respective piston-side tooth 34, as a result of which high surface pressures are avoided and wear is reduced to a minimum. The efficiency is somewhat reduced in this region due to the somewhat higher transverse forces, which is however no longer so important in the case of larger gate angles. In addition, the piston 16 is already in motion in this position, so that a smaller sliding friction coefficient, rather than a static friction coefficient, comes into play with regard to friction.

Fig. 5 and 6 show two teeth 32, 34 of the pinion-and-rack gear 18 of the drive 10 according to the invention, which teeth are shown in fig. 3 as meshing with one another, in the case of a door opening angle of 10 °. In this case, the sliding of the further mating surface B' of the pressure-side flank of the respective pinion-side tooth 32, which is effected with an increasing fan opening angle, onto the further contact region B of the pressure-side flank of the respective piston-side tooth 34 results in a planar contact which brings about a lower surface pressure and thus acts in a wear-inhibiting manner. As already explained, the efficiency is slightly reduced in this region due to the high transverse forces, but this is no longer important in the case of a large opening angle of the fan. By virtue of the fact that the pinion-side mating tooth 32 no longer bears against the edge of the tooth head of the piston-side tooth 34, but rather with its other contact region B, a planar contact is produced, a correspondingly high degree of robustness against wear is achieved.

as can be gathered in particular from fig. 4 and 6, the first contact region a and the further contact region B of the pressure-side tooth flanks of the respective piston-side tooth 34 can be formed at least in part, for example, by at least substantially flat surfaces. Furthermore, the further mating surface B' of the pressure-side flank of the pinion-side tooth 32, which engages with the further contact region B of the pressure-side flank of the piston-side tooth 34, is formed at least in part, for example, by an at least substantially flat surface.

The first contact region a and the further contact region B of the pressure-side flank of the respective piston-side tooth 34 can be separated from one another by a discontinuous transition or can likewise be transitioned into one another via an at least substantially continuous transition region. In the latter case, the first contact region a and the further contact region B of the pressure-side flank of the respective piston-side tooth 34 can merge into one another, for example, via a transition region with a rounded contour. In this case, the rounded contour of the continuous transition region between the first contact region a and the further contact region B of the pressure-side flank of the respective piston-side tooth 34 can be formed in particular by a defined radius, a spline curve and/or the like.

The first contact region a and/or the further contact region B of the pressure-side flank of the respective piston-side tooth 34 may likewise have a rounded profile on its own and/or consist of straight and curved lines, spline curves and/or the like.

Likewise, the first mating face a 'and/or the further mating face B' of the pressure-side flank of the respective pinion-side tooth 32 may have at least partially a rounded contour and/or be composed of straight and curved lines, spline curves and/or the like. The first contact region a and/or the further contact region B of the pressure-side flank of the respective piston-side tooth 34 can accordingly have a varying profile angle at least in sections. In this case, the first contact region a or the further contact region B can also be produced by a contour produced, for example, from a spline curve, which begins at a smaller profile angle and increases in the upper region toward the tooth tip.

The profile angle of the first contact region a is continuously smaller than the profile angle of the other contact region B of the pressure-side tooth flank of the respective piston-side tooth 34.

The projection 40 of the corresponding pinion-side mating tooth 32 does not necessarily have to project significantly. Thus, the projection 40 of the respective pinion-side mating tooth 32 can likewise be convex only to such an extent that it engages with the first contact region a of the pressure-side tooth flank of the respective piston-side tooth in the initial fan-open angle range.

Fig. 7 shows two teeth of the pinion-and-rack gear 18 of an exemplary embodiment of the drive according to the invention meshing with each other in the case of a door opening angle of 3 °, wherein the projection 40 of the respective pinion-side mating tooth 36 projects less strongly than in the case of the embodiment shown in fig. 3 to 6.

If no or only a slightly decreasing door moment with a corresponding shortening of the effective lever arm length of the pinion is required in the pinion-and-rack gear, the respective pairs of teeth 32, 34 of the pinion-side and piston-side toothed sections 24 and 26, which engage one another in the initial fan-open angular range, can likewise be embodied such that a decreasing meshing line is obtained in relation to the longitudinal direction of the piston-side toothed section 26, which is provided as a straight toothed section, or the direction of movement of the piston 16.

Due to the configuration according to the invention of the drive 10, a very small piston-side tooth angle in the initial fan-open angle range, in particular of 0 ° to 4 °, can be achieved, in particular even in the case of non-circular pinion-rack drives, with a door moment which decreases in the initial fan-open angle range due to a corresponding shortening of the effective lever arm length, as a result of which high efficiency, high robustness and low wear are achieved.

List of reference numerals

10 driver

12 casing

14 spring unit

16 piston

18 pinion-and-rack transmission

20 driven shaft

22 pinion

24 pinion-side tooth system

26 mating teeth on the piston side

28 piston side teeth

30 pinion-side mating teeth

32 pinion-side mating teeth

34 teeth on the piston side

36 pinion

38 recess, retraction

40 projection

42 rising line of engagement

44 line of engagement of the descent

A first contact area

a' first mating face

B additional contact area

B' additional mating surfaces

X teeth engaging each other in the initial fan opening angle range

angle of alpha tooth form

Angle of profile of alpha _A first contact area

Tooth profile angle of alpha _B additional contact area