DRIVE FOR A LEAF OF A DOOR OR WINDOW AND METHOD OF MANUFACTURING SAME The invention relates to a drive for a leaf of a door or a window or the like having a housing, at least one piston stored in the housing, in particular, a damping piston and/or spring piston, and a drive shaft which is mounted in the housing so as to rotate about a rotation axis and couples the leaf to the piston, wherein the drive shaft has at least a bearing part for mounting the shaft and a transmission part, in particular a pinion and/or cam disk for transmitting a movement of the shaft to the piston, said bearing part and said transmission park being formed separately from one another, wherein the parts by way of an front contact contour bear axially on one another.
A known, multi-part drive shaft comprises two bearing necks and a central piece or transmission part which can be realized for example as a pinion contour or a cam contour or a cam disk.
An extension is provided on the bearing necks and central piece, by which the components are radially and circumferentially welded to each other.
Laser welding is used here in particular.
The maximum weldable diameter, or the diameter of the extension, is determined by the deepest area of the gearing or the cam contour with respect to a rotation axis.
Because the gearing and cam contour often have very deep areas, the weldable diameter is sometimes very small.
A drive according to the preamble of claim 1 is known from DE 103 16 470 A1. Another drive is known from DE 10 2011 055977 A1. Door closers are often affected by a high torque, which potentially cannot bear a small extension or welding that is planned here, which can lead to the drive shaft breaking.
Furthermore, the running surfaces of the bearing necks and/or a transmission area, in particular, the gearing or the curve contour, of the transmission part must be slightly shortened in order to create free space for the laser beam so that the running faces and the transmission area are not melted during welding.
It is an object of the invention to improve the stability of the connection between a bearing part and a transmission part of the drive shaft in drive of the aforementioned type, particularly so that the drive shaft will withstand higher torques.
This object is achieved by a drive with the characteristics mentioned in Claim 1, and, in particular, by the transmission part being welded with the bearing part in at least a first region of the contact contour, which has a radial height with respect to the rotation axis that is higher than a minimum radial height of the transmission part with respect to the rotation axis.
A particularly wide so-called welding diameter, the effective diameter of the weld joint, is produced by doing this.
The welding diameter is, in the process, not limited to the lowest radial height of the transmission part, but is wider for the purpose of improving the solidity of the connection.
This increases the torsional moment allowable in the weld joint and as a result, the torsion resistance and the stability of the connection or the drive shaft.
It is frequently desirable or necessary for the transmission part to be designed relatively small in areas with respect to the rotation axis, in particular, radially smaller than a bearing surface of the bearing part and/or than a contact portion of the bearing part.
It was known that it is not necessary to limit the welded joint to a circular contact contour within the smallest radial height of the transmission part.
Rather, theoretically the entire radial height of the transmission part, in practice preferably a greater than the smallest radial height of the transmission part, can be utilized for the welded joint in order to achieve a high torsional moment of the weld joint.
According to the invention, a complex transmission part or one with a partially radially small structure and a high degree of stability can be connected together advantageously and this can be done in a particularly simple way, namely by the enlarged weld diameter according to the invention.
The transmission part can also be arranged substantially independently of the bearing surface diameter of the bearing part, in particular with a relatively small radial height area by area, whereas the bearing surface diameter can be relatively large by choice.
Due to the larger weld diameter and resulting enlarged welding surface, the drive shaft can absorb considerably higher torques when dimensions are otherwise identical.
The larger weld diameter also adds the advantage that the welding point is more accessible and, in particular, a welding laser beam can be more easily positioned and can weld into the components without colliding with a transmission area of the transmission part, in particular of a gearing or cam contour and/or a bearing surface of the bearing part.
Consequently, no or only a relatively small axial clearance between bearing surface and transmission area needs to be provided for the welding point to be accessible.
Until now, for example, bearing surfaces and/or a transmission area have been shortened axially to a relatively great extent.
As a result of the invention, shortening like this is no longer or only to a slight extent necessary because the welding point can be arranged relatively far radially on the outside, i.e. is particularly easily accessible.
The function regions of the shaft can be embodied otherwise by the invention, particularly bearing surfaces and transmission area, advantageously designed according to demand, wherein less axial space for the connection of the parts has to be provided.
As a result, bearing and transmission loads can therefore be reduced, and longevity improved.
According to one embodiment, the contact contour in the first region can be in the shape of a circular segment.
The first region can be particularly easily produced this way, for example, by rotating, wherein a particularly uniform, and therefore stable weld joint is made possible.
It can, for example be advantageous for the radial height of the first region to be smaller than the maximum radial height of the transmission part, in particular the same size as, or smaller than, the radial height of the base of the intermediate space between teeth in the first region, which has the smallest radial height.
The contact portion of the transmission part can, for example, have a circumferential contour in the shape of a circular segment in the first region of the contact contour.
In particular, the circumferential contour can deviate in a second region form the circular shape of the first region, in particular, be completely radial in this region.
Alternatively or additionally, the contact portion of the bearing part can, for example, have a completely circular circumferential contour.
Preferably a circumferential contour in the shape of a circular segment of the contact portion of the transmission part in the first region and a circular circumferential contour of the contact portion of the bearing part can be concentrically arranged and/or have an identical radius with respect to the rotation axis.
According to another embodiment, the transmission part is also welded to the bearing part in a second region of the contact contour, which has a radial height that is smaller than that of the first region, in particular wherein the second region has a radial height which is between the minimum radial height of the transmission part and the radial height of the first region.
Preferably the first and the second region of the contact contour can conjointly form the entire contact contour.
Basically, more first and/or second regions can also be provided.
The contact portions of the transmission part and of the bearing part can, according to an advantageous example, have an at least substantially co-aligned external face.
The stability of the weld joint can be further improved by doing this.
In particular, the co-aligned external faces can form a partially circular cylinder jacket.
Provided according to an advantageous further embodiment, the bearing part and the transmission part each bear on one another across the full area.
The first region of the contact contour can advantageously comprise at least half, preferably at least two thirds, more preferably at least three quarters, of the contact contour.
A particularly good degree of stability can be achieved for the weld joint by doing this.
Likewise, the parts can be welded advantageously by way of a plurality of spot welds along the contact contour and/or with at least one weld seam along the contact contour.
In addition, the parts can be advantageously welded by way of a seam and/or completely circumferentially welded along the entire contact contour.
A particularly good degree of stability is achieved by doing this.
In one embodiment, the parts are welded by way of a butt weld, in particular, in the first region and/or in the second region and/or in the region of co-aligned external faces of the parts.
Alternatively or additionally, the parts, in particular, in the second region of the contact contour, can be welded using a fillet weld.
Provided according to a further embodiment, at least one of the parts has an axial protrusion for the bearing on the other part.
Access for a welding device can be made easier by doing this.
Moreover, a distance from the welding to a functional region of the part in question, such as a transmission area or a bearing surface can therefore be created in a particularly simple way, so that the welding process does not negatively affect this functional region.
In an advantageous further embodiment, the protrusion is configured to be cylindrical, in particular with an at least partially circular cross section.
In particular, a completely circular cylindrical protrusion can be provided in the bearing part.
For example, both parts can have an axial protrusion, and the protrusions can be in contact with each other.
The functional surfaces of the parts can be protected in this way from heat input that is too high during the welding process in a particularly simple and effective way.
Provided according to another embodiment, a spot weld and/or a weld seam, in particular, a fillet weld, particularly in the second region, is configured in such a way that the contact contour is smoothed, in particular radiused.
It is generally preferable not to have right angles at the connection point but instead a fillet or a chamfer.
Stress concentrations are sharply reduced by doing this and stability is further improved.
The effect of excess weld material can be advantageously exploited for the smoothing or radiusing.
This causes the welding point to have a somewhat larger volume, even without material allowance, than the connection partner which was previously in the melted area.
An original right angle in the connection partner can in this way be smoothed or radiused by welding, in particular without material allowance, particularly without mechanical follow-up such as grinding or rolling.
Additionally, a free surface or a free section between a circumferential contour of the transmission part or the contact contour and a circumferential contour of the bearing part in the contact area, in particular in the second region, can be melted in order to produce material for the connection and the smoothing.
The minimum radial height of the transmission part with respect to the rotation axis can, in particular, be formed by the radially deepest region of a cam disk of the transmission part with respect to the rotation axis and/or the basis of an intermediate space between the teeth of a pinion of the transmission part, or respectively by an axial extension from this point, for example in an axial protrusion.
The second region can for example, be formed by at least one intermediate space between teeth.
In the case of a pinion, an entire tooth or several teeth can, for example, also be part of the second region.
The parts can be advantageously welded to each other using laser welding.
This allows for a particularly stable connection with the wide welding diameter according to the invention.
A second, separately formed bearing part which is welded to the transmission part on the side that faces away from the first bearing part can also be provided.
Between the second bearing part and the transmission part, in particular, a connection can be provided which corresponds to the connection between a first bearing part and a transmission part.
Between a bearing part and a transmission part, for example, a contact surface can be formed which is limited in particular by the contact contour.
The contact surface can be advantageously oriented perpendicularly to a rotation axis of the drive shaft.
Basically, the contact surface can, for example, be flat.
Alternatively, the contact surface can, for example, be in the shape of a cone.
The contact surface can basically also be eviscerated on the inside, for example in the case of a sleeve, and in this case, in particular, be an annular section.
A protrusion can also be provided, for example on a part within the contact surface and a corresponding recess on another part to center and/or position the parts relative to each other.
The object is also achieved by a production process according to the independent claim here.
In the process, a drive shaft is formed by at least one bearing part and a separate transmission part wherein the parts are by way of a contact contour are brought to bear axially on each other and wherein the transmission part is welded to the bearing part in at least a first region of the contact contour, which has a radial height in relation to the rotation axis which is greater than a minimum radial height of the transmission part.
The components can, for example, be pre-assembled or pre-positioned for this by a tenon and a corresponding drill hole.
All embodiments described in connection with the drive can appropriately be added and reversed for the further development of the method.
The invention is explained below solely by way of example, with reference to the schematic drawing.
Fig. 1 shows a drive shaft.
Fig. 2 shows an enlarged and perspective view of the drive shaft in Fig. 1.
Fig. 3 shows a pinion.
Fig. 4 shows a cam disk.
Fig. 5 shows a drive shaft according to the invention.
Fig. 6 shows an enlarged and perspective view of the drive shaft in Fig. 5.
Fig. 7 shows a pinion according to the invention.
Fig. 8 shows a cam disk according to the invention.
Fig. 9 shows another further enlarged and perspective view compared to
Fig. 6 of the drive shaft in Fig. 5.
Fig. 10 shows a welded contact contour of the drive shaft in Fig. 5. shows a welded contact contour of another drive shaft according to
Fig. 11 the invention, with a cam disk.
Fig. 1 to 4 also show a drive shaft or transmission part which are not designed according to the invention, and which are used to explain the technical background of the invention. Nevertheless, individual characteristics shown in it can be added to further develop the invention. In Fig. 1, a drive shaft 20 is shown which comprises a first bearing part 22, a second bearing part 24 and a transmission part 26 arranged between them. The bearing parts 22 and 24 and the transmission part 26 are separately formed from each other, bear on each other with respective axial protrusions 28 or 30 and are welded hereto in a circumferential manner. This can, in particular, be done using a welding laser beam 32. The transmission part 26 is designed as a pinion and comprises a plurality of teeth 34 arranged around the circumference. As can be seen in Fig. 2, these teeth 34 have a different height with respect to a rotation axis of the drive shaft 20. The radial height of the transmission part 26 is, at least in one a region of an intermediate space between teeth, smaller than the radial height of a bearing surface 38 of the bearing part 22. This also applies in comparison to the bearing part 24 which, however, cannot be seen in Fig.
2. The transmission part 26 bears on the bearing part 22 with a contact contour 40. The parts are welded to each other along the contact contour 40. The radius of the protrusions 28 and 30 or of a weld seam produced by the laser beam 32 along the contact contour 40 is smaller than the smallest radial height of the transmission part 26 which is determined here by the base 36 of an intermediate space between teeth. In Fig. 3 the pinion 26 is shown separately and in an axial top view of its protrusion 30. In addition, a rotation axis 41 is delineated which runs perpendicularly to the image plane of
Fig. 3. The radial height of the protrusion 30 with respect to the rotation axis 41 which corresponds to the radial height of the contact contour 40 is selected as smaller than, or at most as big as, the smallest radial height of the transmission part 26, here the height of the base of the intermediate space between teeth 36. A representation corresponding in perspective to Fig. 3 shows in Fig. 4, a transmission part 42 designed as a cam disk, likewise with a protrusion 30. Here also, the radial height of the protrusion 30 has been selected so that a radially smallest region of the transmission part 42 here has a radially smallest region 44 of the contour of the cam disk 42 which has an identical or greater axial height. The protrusion 30 is consequently arranged completely within the contour of a transmission area of the transmission part. An embodiment of a drive shaft according to the invention is described below. The reference signs are used for a better orientation corresponding to the previous embodiments.
Fig. 5 shows a drive shaft 20 according to the invention with a first bearing part 22, a second bearing part 24 and a transmission part 26. The parts are formed separately from each other, bear on each other axially and are welded to each other. In Fig. 6 a contact area between the bearing part 22 and the transmission part 26 has been enlarged and is shown in a perspective view. A welding laser beam 32 is indicated showing how it welds the parts 22 and 26 to each other. The bearing part 22 and the transmission part 26 bear on each other axially with respective protrusions 28 and 30. Two bases 36 of respective intermediate spaces between teeth are present and radially smaller than the radial height or the diameter of the protrusion 30 in the first region and the completely circular-cylindrical protrusion 28. In Fig. 7 the transmission part 26 designed as a pinion is shown separately and in an axial top view. As can be seen here well, the two bases 36 of intermediate spaces between teeth are designed radially smaller than a radially larger circumferential region in the shape of a circular segment of the protrusion 30, which forms a first region 45 of the contact contour 40. A tooth 34 is actually even designed completely radially smaller than the circumferential region in the shape of a circular segment or the first region 45. The radial height of the first region 45 is smaller than the maximum radial height of the transmission part 26, here defined by the rightmost tooth in Fig. 7, in particular, of equal size to, or smaller than, the radial height of the base 36 of the intermediate space between teeth in the first region 45, which has the smallest radial height. In the first region 45 the circumferential contours of the protrusions 28 and 30 correspond, and the parts 22 and 26 or the protrusions 28 and 30 have co-aligned external faces in the first region 45. The protrusion 28 is implemented in this embodiment example as a completely circular cylinder and has a completely circular cross-section and a completely circular circumferential contour. As can be clearly discerned in Fig. 7, the intermediate spaces between teeth and the tooth 34 deviate inwardly from the corresponding circular shape, namely in a second region 46 of the contact contour 40. The protrusion 30 is therefore only designed as a partially circular cylinder. In Fig. 8, a transmission part developed as a cam disk 42 is shown, which, for example, can be provided in a drive shaft according to Fig. 5 instead of the transmission part 26. The cam disk 42 comprises a curved surface, which is variable in its radial height, as a transmission area. A protrusion 30 is designed for the most part as a circular cylinder and is, in fact, concentric to the rotation axis 41. A radially smallest region 44 of the cam disk 42 with respect to the rotation axis 41 is visible in Fig. 8 on the left. This region 44 has a radial height which is smaller than the radial height of the circular first region 45 of the contact contour 40 or the protrusion 30. The bearing parts 22 and 24 described here, or the transmission parts 26 and 42, all have axial protrusions 28 or 30 without exception for mutual axial contact. However, such protrusions are not absolutely necessary. Basically also, only one-sided protrusions or even no protrusions can be provided between the connection partners Nevertheless, protrusions of this sort can provide an advantageous exposure of functional surfaces of the bearing parts or the transmission parts. In Fig. 9, the contact area between the bearing part 22 and the transmission part 26 has been further enlarged and represented with a slightly altered perspective from that in Fig.
6. Between the connection partners, the contact contour 40 is delineated with a first region 45 and a second region 46. The bearing part 22 and the transmission part 26 bear on each other with opposite front surfaces in each case. By means of Fig. 9, in particular in combination with Fig. 7, it can particularly easily be seen that the first region 45 of the contact contour 40 has a radial height with respect to the rotation axis 41, which is larger than a minimum radial height of the transmission part 26 with respect to the rotation axis
41. The transmission part 26 is welded with the bearing part 22 at least in the first region 45, but is advantageously welded as well in the second region 46. The contact contour 40 is developed in the shape of a circular segment, namely circular in the first region 45 and in the second region 46 with a shape that deviates from that in the first region 45. In the second region 46, the contact contour 40 is developed so that it corresponds to the contour of a transmission area of the transmission part 26, here the contour of the corresponding intermediate space between teeth or of the tooth 34 of the transmission part 26. The protrusion 28 of the bearing part 22 is developed as a completely circular cylinder. Between the circular circumferential contour of the protrusion 28 and the circumferential contour of the protrusion 30 or of the contact contour 40 in the second region 46, there is a free surface 50 on the front side of the protrusion 28 or of the bearing part 22. Between the free surface 50 and the tooth contour in the second region 46 there is a right angle. In this example, the front surface of the protrusion 28 is oriented perpendicularly to the rotation axis 41 and the tooth contour is completely axial. The bearing part 22 and the transmission part 26 can preferably be welded at several spot welds along the contact contour 40 or by way of a weld seam, which runs along the entire contact contour 40. A butt weld is preferably provided between the parts in the first region 45 in the second region and/or the contact contour 40 or in the region of a co- aligned outer surface of the protrusions 28 and 30. In the second region 46 of the contact contour, a fillet weld is on the contrary preferable. The spot welds and/or weld seams are preferably done by means of laser welding, particularly without allowance. In Fig. 10, a perspective view of the drive shaft 20, similar to Fig. 9, is shown, wherein the parts 22, 26 have been welded but with a weld seam 52 In this embodiment, this seam extends along the entire contact contour 40 wherein it is designed in the first region 45 as a butt weld and in the second region 46, as a fillet weld. The contact contour 40 is smoothed and radiused in the second region 46 compared to the right angle between the tooth contour and the free surface 50 described in relation to
Fig. 9. The weld seam 52 has, in particular, a concave structure in this region. This can, for example, be introduced by advantageously exploiting the effect of the excess weld material. The free surface 50 can also be melted during the welding process in order to produce additional material for the weld seam 52 or the smoothing or filleting. Due to smoothing and/or radiusing, there is no longer a right angle between the tooth contour and free surface 50 or between transmission part 26 and bearing part 22, so that stress concentration connected with this is avoided or reduced. The weld joint therefore has a particularly high degree of stability. In Fig. 11 is shown one of the views corresponding to Fig. 10 for a drive shaft with a transmission part developed as a cam disc 42. Here too, a free surface 50 and a weld seam 52 which smooths the contact contour in the second region are visible.
The second region is here defined by a radially smallest region 44 of the cam disk 42. Here also, the seam 52 reduces stress and provides for a good degree of stability in the weld joint.
As can already be seen from a comparison of Fig. 1 and Fig. 5, the drive shaft of Fig. 5 has a clearly larger weld diameter in the contact or connection region between the bearing parts 22 or 24 and the transmission part 26. In the second region of the contact contour, the radial height of the spot welds or the weld seam is in fact small in terms of area in comparison to the greater radial height of the contact contour, therefore in this example in comparison to the radius of the first region of the contact contour.
Nevertheless, the large radius or diameter of the welding has a particularly positive effect on stability.
Moreover, the torsional moment of the weld seam, substantially increasing to the fourth power with the radius, is advantageously exploited here.
This means that when the second region of the contact contour presents a slight weakness in comparison to the first region, the gain in radius in the first region in comparison to the drive shaft of Fig. 1 nevertheless has a considerably positive effect on the stability of the weld joint.
Against this background, it is particularly advantageous when the first region of the contact contour or a weld seam provided there extends over at least half, in particular at least three quarters of the circumference.
List of reference signs Drive shaft 22 First bearing part 24 Second bearing part 26 Transmission part 28 Protrusion Protrusion 32 Welding laser beam 34 Tooth 36 Base of an intermediate space between teeth 38 Bearing surface Contact contour 41 Rotation axis 42 Cam disk 44 Radially smallest region First region 46 Second region Free surface 52 Weld seam