Harmonic drive and method for producing a harmonic drive

Abstract

A harmonic drive, more particularly a harmonic drive in an electromechanical camshaft phaser, comprising: a drive element (2); a flexible transmission element (26) connected to the drive element (2) and having external teeth (29); and an output element (4) designed as a ring gear and having internal teeth (30) partially meshing with the external teeth (29). The flexible transmission element (26) is pot-shaped and is coupled to the drive element (2) radially inside the external teeth (29) in a torque-transmitting manner.

Description

Technical Field

[0001] The invention relates to a harmonic drive which is particularly suitable for use as an adjusting gear in an electromechanical camshaft adjuster and further relates to a method for producing such a harmonic drive. Background Art

[0002] A general harmonic drive is known, for example, from DE 10 2016 218 575 A1. The harmonic drive has a flexible externally toothed transmission element in the form of a collar sleeve. The collar sleeve has a cylindrical section provided with external teeth. Starting from the cylindrical section, a flange points radially outwards, which is also referred to as a collar. The collar is connected to the housing of the harmonic drive by means of a threaded connection. The housing is rotatable as a whole and represents the drive element of the harmonic drive. The output element is designed as a ring gear rotatably mounted in the housing and has internal teeth that partially mesh with the external teeth of the flexible transmission element.

[0003] Another harmonic drive is disclosed in DE 10 2017 126 527 A1, which has a flexible transmission element designed as a collar sleeve. In this case, compared with DE 10 2016218 575A1, the output element designed as a ring gear is also designed as a flexible transmission element.

[0004] DE 10 2017 114 175 B3 and DE 10 2017 103 988 B3 describe harmonic drives with improved collar sleeves. In these cases, too, a flange (which does not necessarily form a complete annular disk shape) points radially outwards from the outer toothed cylindrical section of the flexible transmission element. In both cases, the flange (i.e. the collar) having the basic shape of an annular disk is followed by a section which concentrically surrounds the outer toothed section and is connected to the drive element in a rotationally fixed manner.

[0005] Documents DE 10 2016 205 748 B3, DE 10 2017 121 320 B3 and DE 10 2016204 784A1 show different designs of harmonic drives, each of which acts with a pot-shaped flexible transmission element. In all cases, the pot-shaped flexible transmission element is permanently connected to the output shaft of the harmonic drive.

[0006] A common feature of harmonic drives with annular (i.e., cap-shaped) transmission elements and harmonic drives with pot-shaped elastic transmission elements is that the teeth of the flexible transmission element engage only with the teeth of another, separate, usually rigid transmission element. This is a fundamental difference from harmonic drives, which have a flexible ring as elastic transmission element: the teeth of the flexible ring mesh simultaneously with the teeth of the drive-side ring gear and with the teeth of the output-side ring gear. In this context, reference is made to DE 10 2014 202 060 A1 as an example. A flexible ring is generally understood to mean a toothed, annular, elastic, elastic transmission element which has no radially inwardly or outwardly directed extensions, for example in the form of a base or a flange. Summary of the invention

[0007] The object of the invention is to disclose a harmonic drive which is further developed compared with the prior art and which features a particularly advantageous ratio between transmittable torque and required installation space while providing a construction which is easy to produce.

[0008] According to the present invention, this object is achieved by a harmonic drive and a method for producing a harmonic drive. The configurations and advantages of the present invention explained below in conjunction with the production method are also similarly applicable to the device (ie, the harmonic drive), and vice versa.

[0009] In a basic concept known per se, a harmonic drive comprises a drive element, a flexible transmission element having external teeth connected to the drive element, and an output element designed as a ring gear having internal teeth partially meshing with the external teeth of the flexible transmission element.

[0010] According to the invention, the flexible transmission element is pot-shaped, wherein the flexible transmission element is coupled to the drive element radially inside its outer teeth in a manner suitable for transmitting torque.

[0011] The pot-shaped design of the flexible transmission element means that a radially inwardly directed section extends from the sleeve-shaped section of the flexible transmission element provided with the external teeth and is referred to as the bottom of the pot-shaped transmission element. The bottom has a basic shape of an annular disk and is not closed. The flexible transmission element does not have a section that points radially outwardly from the external toothed section. This means that the outer circumferential surface of the flexible transmission element is formed by its external teeth. Compared to conventional transmissions with flexible transmission elements designed as collar sleeves, a particularly large tooth diameter of the flexible transmission element can be selected, which means a particularly high transmittable torque in relation to the required installation space.

[0012] The fundamental difference between the harmonic drive according to the invention and conventional harmonic drives with a pot-shaped elastic transmission element is that the flexible pot-shaped transmission element is non-rotatably held on the drive element of the harmonic drive instead of on the output element. The holding of the pot-shaped flexible transmission element on the drive element may be affected by play. Here, the play between the drive element and the flexible pot-shaped transmission element is preferably smaller in the circumferential direction of the mentioned elements than in the other directions, i.e. in the axial direction and in the radial direction.

[0013] In a preferred embodiment, there is a form-fitting connection between the drive element and the flexible pot-shaped transmission element, wherein an opening is located at the bottom of the flexible transmission element, in which a form-fitting element of the drive element, in particular in the form of a pin or a knob, engages. In a particularly preferred embodiment, the opening at the bottom of the flexible transmission element is delimited in both circumferential directions of the transmission element by contact flanks bent out from the bottom of the flexible transmission element. Embodiments can also be implemented in which the form-fitting element on the drive element side and the form-fitting element on the flexible transmission element side are designed in the same way, for example as teeth.

[0014] By means of the contact flanks (i.e. lugs bent out from the bottom of the flexible pot-shaped transmission element), sliding surfaces are provided, which serve to transmit torque between the drive element and the flexible transmission element and to couple the two elements mentioned to one another, with virtually no play in the circumferential direction, wherein mobility between the two elements is maintained, in particular in their axial direction. In this way, during operation of the harmonic drive, forced deformations of the sleeve-shaped external toothed section of the flexible transmission element can be absorbed by the equally elastic bottom of the transmission element, wherein the backlash connection of the flexible transmission element on the drive element contributes significantly to the fact that torque irregularities (so-called fluctuations) are largely avoided. The controllability of the harmonic drive and the durability of the elastic transmission element also benefit from the avoidance of torque irregularities.

[0015] By means of a non-cutting process, the openings and the contact flanks can be produced efficiently. In the same way, a stop contour can be generated in the inner circumferential surface of the sleeve-shaped section of the pot-shaped transmission element, which stop contour fixes a wave generator which is provided for deforming the flexible transmission element in the axial direction relative to the flexible transmission element and thus relative to the drive element. The stop contour mentioned above is, for example, an approximately point-shaped depression which can be regarded as a knob on the inner circumferential surface of the sleeve-shaped section of the pot-shaped flexible transmission element. The depression is preferably located in an area of ​​the sleeve-shaped section without external teeth, that is, the sleeve-shaped section has a smooth outer circumferential surface in addition to the depression.

[0016] In the axial direction opposite to the base of the flexible transmission element, the wave generator is preferably fixed directly by means of an output element designed as a ring gear. The ring gear itself is fixed relative to the drive element in this direction, for example by means of a locking ring engaging in a groove on the inner circumferential surface of the drive element.

[0017] The adjustment range of the harmonic drive is determined by the maximum rotation angle between the drive element and the output element. Preferably, the rotation angle limitation is formed directly by the contours of the drive element and the output element.

[0018] According to a first possible variant, the rotation angle limitation is formed by a stop section of the drive element and a recess in the annular circumferential end face strip of the output element.

[0019] According to a second possible variant, the rotation angle limitation is formed by an opening in the drive element and a stop section of the output element engaging in the opening.

[0020] Regardless of the type of rotation angle limitation, harmonic drives can be produced as follows:

[0021] A pot-shaped drive element is provided, which is designed as a drive element of a belt drive, in particular a chain drive, wherein a first type of positive-fit element is formed on the bottom of the drive element,

[0022] providing a flexible pot-shaped externally toothed transmission element, wherein a second type of form-fitting element is formed on the bottom of the transmission element,

[0023] providing a wave generator designed to deform a flexible transmission element, which in particular comprises a ball bearing as rolling bearing,

[0024] An internally toothed output element is provided which is designed as a ring gear and is provided for a non-rotatable connection to a shaft to be adjusted,

[0025] Insert the wave generator into the flexible transmission element,

[0026] The assembly formed by the wave generator and the flexible transmission element is inserted into the output element, the so-called regulating shaft.

[0027] Slide the drive element onto the output element until a torque-transmitting connection is established between the individual form-fitting elements.

[0028] The output element is fixed in the axial direction relative to the drive element by the locking ring.

[0029] If the harmonic drive is used to adjust the camshaft, the output element must be non-rotatably connected to the camshaft. The end face of the harmonic drive that is connected to the shaft to be adjusted (i.e., the camshaft) is called the output side end face. The output element is designed so that the bottom of the ring gear (i.e., pot-shaped) is located on the output side end face of the harmonic drive. The unclosed bottom of the drive element is located on the end face of the harmonic drive opposite to the shaft to be adjusted. The bottom of the flexible pot-shaped transmission element faces the same end face. This means that there are two pot-shaped elements, namely the drive element and the flexible transmission element, which are respectively open to the output side of the harmonic drive. The output element engages in the annular cavity formed between the two pot-shaped elements, and most or all of the annular cavity is located inside the pot-shaped drive element.

[0030] In a preferred embodiment, the drive element is also designed as a transmission element of a belt drive, in particular a sprocket. The drive element can also be a pulley or a gear. In principle, the drive element can also be connected (for example, tightened) to a separate sprocket, pulley or gear. In the case where the sprocket or pulley is designed as an integral part of the drive element, such a threaded connection is not required. Similarly, in the described design, no threaded connection is provided between the flexible transmission element and the drive element. In principle, any type of connection between the flexible transmission element and the drive element can be selected, provided that the required torque transmission capacity is given. In addition to non-positive connections, there are in particular material connections, in particular in the form of welded connections or soldered connections.

[0031] The drive element, preferably in the form of a sprocket, can be produced, for example, by powder metallurgy, ie manufactured as a sintered component. Instead of or in addition to a powder metallurgy process, a machining process is also suitable for producing the drive element.

[0032] In an alternative embodiment, the drive element is produced by means of forming. Examples of manufacturing steps for producing the sprocket include sheet metal forming, stamping and rolling. In a manner known per se, the surface properties can be changed by heat treatment of the sprocket, i.e. the drive element of the harmonic drive. The bearing surface of the drive element can also be hard machined.

[0033] The sprocket will be designed according to the chain used, for example a toothed chain or a roller chain. The same applies if the drive element is designed as a pulley. In all cases, the forces are preferably introduced from the drive element into the other components of the harmonic drive in such a way that as little overturning moment as possible occurs between the drive element and the output element. In general, the narrow design of the harmonic drive (i.e. the small expansion of the harmonic drive in the axial direction) is conducive to operation with only small or negligible overturning moments. Due to the low overturning moment, the fixing element (especially in the form of a locking ring) that holds the output element in the drive element is only exposed to low mechanical loads.

[0034] Compared to conventional harmonic drives using flexible rings, the harmonic drive according to the invention requires only a single internally toothed transmission element. In an advantageous embodiment, there are no screws on the drive element, which at the same time represents the housing of the harmonic drive. In summary, the drive element is a multifunctional component. The following are the individual functions of the drive element:

[0035] Providing a profile for introducing the torque into the drive element, i.e. designing the drive element as a chain or pulley or gear,

[0036] a non-rotatable and preferably at the same time selectively backlash-influenced holding of the flexible transmission element on the base of the drive element, ie a connection with direction-dependent backlash,

[0037] Axial bearing of the output element in the drive element,

[0038] Radial bearing of the output element in the drive element,

[0039] Limitation of the rotation angle between the drive element and the output element.

[0040] No separate axial bearing disc is required to support the output ring gear in one direction. The fact that the harmonic drive has only one pair of teeth contributes to the mechanical accuracy of the harmonic drive. The mounting of the output ring gear in the drive element with play is independent of the method of manufacturing the drive element and the output element. Just like the drive element, the output element can also be designed as a sintered component.

[0041] The kinematics of the harmonic drive according to the invention are substantially the same as those of a conventional harmonic drive with a collar sleeve. Therefore, the harmonic drive is usually designed as a spur gear set. This means that when the adjustment element of the wave generator rotates in a first direction relative to the drive element, the output element is adjusted in the same direction relative to the drive element.

[0042] Harmonic drives are not only used as regulating gears in vehicle technology, but can also be used in industrial applications, for example in robots or machine tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Several exemplary embodiments of the present invention are described in more detail below with the aid of the accompanying drawings. In the drawings:

[0044] Figure 1 A first exemplary embodiment of a harmonic drive is shown in a sectional perspective view,

[0045] Figure 2 Shown according to Figure 1 The design of the harmonic drive shown is a drive element of a sprocket,

[0046] Figure 3 and Figure 4 Shown according to Figure 1 The design shown is a flexible transmission element of a harmonic drive for a toothed tank,

[0047] Figure 5 Shown according to Figure 2 The drive element shown inserted into the toothed can,

[0048] Figure 6 Shown according to Figure 1 The output elements of the harmonic drive shown,

[0049] Figure 7 The cross-sectional perspective view shows the Figure 2 The insertion shown is based on Figure 6 The output components shown and according to Figure 3 The toothed tank and associated wave generator sprocket shown,

[0050] Figure 8 A second exemplary embodiment of a harmonic drive is shown in a sectional perspective view,

[0051] Fig. 9 and Fig.10 The exploded view shows the Figure 8 The harmonic drive device shown,

[0052] Fig.11 Shown according to Figure 8 A detailed view of a harmonic drive is shown,

[0053] Fig.12 Shown according to Figure 8 The drive element (i.e., sprocket) of the harmonic drive device shown has an output element and a flexible transmission element inserted therein,

[0054] Fig.13 The cross-sectional perspective view shows the Fig.12 A detailed section of the arrangement shown,

[0055] Fig.14 Shown according to Fig.12 The output elements of the arrangement shown,

[0056] Fig.15 Shown according to Fig.14 The detailed section of the output element is shown,

[0057] Fig.16 Shown according to Figure 8 The drive elements of the harmonic drive device shown,

[0058] Fig.17 Shown according to Fig.16 Detailed section of the drive element shown,

[0059] Fig.18 Shown according to Fig.16 The drive element shown inserted into the toothed can,

[0060] Fig.19 Components of a third exemplary embodiment of a harmonic drive are shown in a sectional perspective view,

[0061] Fig. 20 Another cross-sectional perspective view shows the Fig.19 The harmonic drive device shown,

[0062] Fig.21 Shown according to Fig.19 A perspective view of the output side of a harmonic drive is shown. DETAILED DESCRIPTION

[0063] Unless otherwise specified, the following description refers to all exemplary embodiments. In the drawings, parts that correspond to each other or have substantially the same effect are always marked with the same reference numerals.

[0064] A harmonic drive, generally designated by reference numeral 1, is provided as an adjusting gear for an electromechanical camshaft adjuster of an internal combustion engine. The harmonic drive 1 is a three-shaft drive, with regard to its basic function, reference is first made to the above-mentioned prior art.

[0065] The harmonic drive 1 has a drive element 2, which at the same time represents the housing of the harmonic drive 1. The sprocket 3 is an integral part of the drive element 2. Figure 1 In the exemplary embodiment of the invention, the drive element 2 is manufactured as a sintered component. Figure 8 In the exemplary embodiment of , the drive element 2 is a transmission element produced via a forming process.

[0066] In each case, the drive element 2 is driven by a chain (not shown), which rotates at half the crankshaft speed. A ring gear rotatably mounted in the drive element 2 is provided as an output element 4 of the harmonic drive 1. The ring gear 4 is firmly connected to the shaft to be adjusted, i.e. the camshaft of the internal combustion engine, by means of a central screw (not shown). The end face of the harmonic drive 1 connected to the camshaft to be adjusted is referred to as the output-side end face S AB The opposite end face is called the first end face S 1 . On the first end surface S 1 There is an electric machine (not shown) which is arranged to drive the harmonic drive 1 .

[0067] Like the output element 4, the drive element 2 has the basic shape of a can. Figure 1The conical outer circumferential surface 6 in the case of the harmonic drive 1 is adjacent to the bottom (indicated by 5 in each case) of the drive element 2 located on the first end face S1 of the harmonic drive 1. Figure 8 In the case of , the bottom 5 is adjoined by a cylindrical outer circumferential surface 7 which merges into the sprocket 3. Fig.19 In the case of the first tapered outer circumferential surface 6, the first tapered outer circumferential surface 6 adjoins the bottom 5 and extends all the way to the sprocket 3. The opposite end face of the sprocket 3 merges into the second tapered outer circumferential surface 9, which faces the output side end face S AB Gradually tapering. Figure 1 Such a second tapered outer circumferential surface 9 is also provided in the exemplary embodiment of FIG. 1 , but is less obvious.

[0068] In each case, the outer circumferential surfaces 6, 7, 8, 9 are arranged radially outside a cylindrical inner circumferential surface 10 which serves as a radial sliding bearing surface relative to the output element 4. The relevant radial sliding bearing surface of the output element 4 is formed by a cylindrical section 11 of the output element 4. The cylindrical section 11 is directed toward the output-side end surface S by means of a locking ring 12 in the drive element 2. AB The locking ring 12 engages in a circumferential groove 13 on the inner circumferential surface of the drive element 2. In the opposite axial direction, i.e. towards the first end face S 1 The output element 4 is mounted by means of an axial sliding bearing surface 14 formed directly by the bottom 5. The bottom 5 of the drive element 2 is disposed on the output side end surface S AB The bottom 15 is located opposite to the bottom of the output element 4 (indicated by 15). Each bottom 5, 15 is not closed, that is, it is only designed in the shape of an annular disk, wherein the bottom 15 extends further toward the center axis of the harmonic drive than the bottom 5. The inner boundary of the bottom 15 is formed by a pin 16 protruding from the output-side bottom 15. When the harmonic drive 1 is installed, the above-mentioned central screw tightened into the camshaft is inserted through the opening marked 17 (which is formed by the hollow pin 16). The camshaft to be adjusted can be a camshaft or an exhaust camshaft of an internal combustion engine.

[0069] The adjustment range of the camshaft adjuster, which together with the harmonic drive 1 acts as an adjustment gear, is delimited by a rotation angle limit, which is generally indicated by 18. The rotation angle limit 18 is formed by a drive-side stop contour 19 and an output-side stop contour 20. The drive-side stop contour 19 is formed directly by the drive element 2, while the output-side stop contour 20 is formed directly by the output element 4. Figure 1 and Fig.19In the exemplary embodiment of the present invention, a stop segment 21 is formed on the inner side of the bottom 5. The stop segment 21 extends at an angle of less than 60° in the circumferential direction of the bottom 5, which is generally annular disc-shaped. The stop segment 21 cooperates with the adjustment window 22 (i.e., the first end face of the output ring gear 4) when it is opened. The adjustment window (also commonly referred to as a recess) extends over an angle of more than 120° on the circumference of the cylindrical section 11 of the output element 4, thereby interrupting the end face rod 23 of the output element 4.

[0070] On the other hand, according to Figure 8 In the exemplary embodiment of the drive element 2, the drive element 2 has an opening 24 bent into a circular arc shape as part of the rotation angle limitation 18. The stop section 25 of the output element 4 engages in the opening 24. The stop section 25 extends over an angle of less than 45° on the opening end face of the output ring gear 4.

[0071] In all exemplary embodiments, the pot-shaped flexible transmission element 26 is placed on the inner side of the bottom 5, such as Figure 3 and Figure 4 As shown. The bottom of the pot-shaped transmission element 26 (i.e. the flexible pot), which is indicated by 27, has the basic shape of an annular disk, which is attached to the bottom 5, which is also annular disk-shaped. The radial outer edge of the bottom 27 merges into the cylindrical section 28 of the flexible pot 26. On the outer circumferential surface of the cylindrical section 28, an outer tooth 29 is formed, which partially engages in the inner tooth 30 of the output ring gear 4. The two diametrically opposite engagement areas between the teeth 29, 30 are determined by the wave generator 31. The wave generator 31 includes a ball bearing indicated by 32. The inner ring of the ball bearing 32, indicated by 33, is non-rotatably connected to the motor shaft of the motor for operating the harmonic drive 1 via a bolt 34, which bolt will be assigned to a compensating coupling (not shown).

[0072] In a manner known per se, the outer circumferential surface of the inner ring 33 is designed as a non-circular elliptical rolling element raceway for the balls 35 (i.e. rolling elements). The balls 35 are guided in a cage 36 and in contact with an outer ring 37, which is elastic compared to the inner ring 33. The cylindrical section 28 of the flexible pot 26 directly surrounds the outer ring 37 without being permanently connected to it. The slightly different number of teeth of the outer teeth 29 (on the one hand) and the inner teeth 30 (on the other hand) ensures that a complete rotation of the inner ring 33 relative to the drive element 2 is converted into only a slight pivoting between the drive element 2 and the output element 4.

[0073] The outer ring 37 and thus the entire wave generator 31 are fixed in the axial direction relative to the flexible transmission element 26 by means of several recesses 38, which can be seen in the form of almost point-shaped knobs on the inner circumferential surface of the cylindrical section 28. In the opposite axial direction, i.e. towards the output-side end face S ABThe wave generator 31 is directly fixed in the axial direction by means of the bottom 15 of the output element 4 .

[0074] For details about the flexible transmission element 26, refer to Figure 3 and Figure 4 , Figure 3 and Figure 4 Relates to all exemplary embodiments. The base 27 of the flexible transmission element 26 has a plurality of openings 39, 18 in the exemplary embodiment. The circumferential boundaries of the openings 39 are delimited by contact flanks 40, which are also referred to as lugs for short and are formed by material bent out of the base 27. Each opening 39 merges radially inwards into an inner widening 41. Each opening 39 merges radially outwards into an outer widening 42. In each case, the widening is related to the circumferential direction of the annular disc-shaped base 27 compared to the central section delimited by the lugs 40. Thus, overall, each opening 39 has the basic shape of a double T when viewed from the end face. In the radial direction of the transmission element 26, the outer widening 42 is wider than the inner widening 41. This results in the asymmetry of the double T. Overall, each opening 37 extends over almost the entire width to be measured in the radial direction of the annular disc-shaped base 27. The annular circumferential inner edge strip of the base 27 is indicated by 43. The inner edge strip 43 represents the radial inner boundary of all openings 39. The openings 39 extend at their radial outer edge approximately to the cylindrical section 28 of the transmission element 26. Overall, the bottom 27 thus has considerable elasticity.

[0075] In the circumferential direction, the bottom 27 and therefore the entire flexible transmission element 26 are coupled to the bottom 5 of the drive element 2 in a form-fitting manner. For this purpose, a number of form-fitting elements 44 corresponding to the number of openings 39 are present on the inner side of the bottom 5. When observing the pot-shaped drive element 2, the form-fitting elements 44 each have a cubic shape, wherein a form-fitting element 44 engages in each opening 39. The side faces of the form-fitting elements 44 abut against the contact flanks 40 in such a way that a form-fitting connection with little play suitable for transmitting torque is formed between the drive element 2 and the transmission element 26 in the circumferential direction of the above-mentioned elements 2, 26. In the axial direction and radial direction of the elements 2, 26, mobility is maintained between the bottom 27 and the bottom 5 of the flexible pot 26, so that the transmission element 26 is mounted on the drive element 2 with play.

[0076] In accordance with Figure 1 and Fig.19 In the exemplary embodiment of the invention, the form-fitting element 44 is produced by powder metallurgy as an integral part of the drive element 2. Figure 8In the exemplary embodiment of , the form-fit element 44 is produced by means of forming, like the entire drive element 2. In this case, a substantially rectangular recess 45 can be seen on the outside of the base 5, which is produced by material displacement during the forming of the form-fit element 44. In any case, the form-fit element 44 interacts directly with the opening 39 delimited by the contact flank 40 representing the corresponding form-fit element.

[0077] When assembling the harmonic drive 1, the wave generator 31 is first inserted into the pot-shaped flexible transmission element 26 in each case. The resulting assembly is also referred to as the adjustment shaft 46. The adjustment shaft 46 is then pushed into the output ring gear 4. Here, the external teeth 29 engage in the internal teeth 30 in two mutually opposite circumferential regions. The drive element 2 is then inserted from the first end face S 1 Push onto the output element 4 until a positive connection is established between the flexible transmission element 26 and the drive element 2. As a final assembly step, the locking ring 12 is inserted into the groove 13. This provides the full functionality of the harmonic drive 1, wherein no threaded connections are present in the harmonic drive 1.

[0078] Description of Reference Numerals

[0079] 1 Harmonic drive 2 Drive element 3 Sprocket 4 Output element, output ring gear 5 Bottom 6 Conical outer circumferential surface 7 Cylindrical outer circumferential surface 8 First conical outer circumferential surface 9 Second conical outer circumferential surface 10 Cylindrical inner circumferential surface; radial sliding bearing surface 11 Cylindrical section of output element 12 Locking ring 13 Recess 14 Axial sliding bearing surface 15 Bottom 16 Pin 17 Opening 18 Rotation angle limitation 19 Drive-side stop contour 20 Output-side stop contour 21 Stop section 22 Recess, adjustment window 23 Strip 24 Opening 25 Stop section 26 Flexible transmission element, flexible ring 27 Bottom 28 Cylindrical section 29 External toothing 30 Internal toothing 31 Wave generator 32 Ball bearing 33 Inner ring 34 Bolt 35 Rolling element, ball 36 Cage 37 Outer ring 38 Recess 39 Opening 40 Contact flank 41 Inner widened section 42 Outer widened section 43 Inner edge strip 44 Form-fit element 45 Recess 46 Adjustment shaft S AB Output side end surface S 1 First end surface.

Claims

1. A harmonic drive device comprising: a drive element (2); a flexible transmission element (26) connected to the drive element (2) and having external teeth (29); and an output element (4) designed as a ring gear and having internal teeth (30) partially meshing with the external teeth (29), characterized in that: The flexible transmission element (26) is pot-shaped and is coupled to the drive element (2) radially inside the outer teeth (29) in a torque-transmitting manner, forming a rotation angle limitation (18) between the drive element (2) and the output element (4).

2. The harmonic drive device according to claim 1, characterized in that: The flexible transmission element (26) is coupled to the drive element (2) in a form-fitting manner.

3. The harmonic drive device according to claim 2, characterized in that: The flexible transmission element (26) has a base (27) with an opening (39), into which a positive-fit element (44) of the drive element (2) engages.

4. The harmonic drive device according to claim 3, characterized in that: The opening (39) is delimited in two circumferential directions of the flexible transmission element (26) by contact flanks (40) bent out from the bottom (27) of the flexible transmission element (26).

5. The harmonic drive device according to claim 1, characterized in that: The rotation angle limitation (18) is formed by a stop section (19) of the drive element (2) and a recess (22) in an annular circumferential end face strip (23) of the output element (4).

6. The harmonic drive device according to claim 1, characterized in that: The rotation angle limitation (18) is formed by an opening (24) in the drive element (2) and a stop section (25) of the output element (4) engaging in the opening (24) of the drive element.

7. The harmonic drive device according to one of claims 1 to 6, characterized in that The drive element (2) is designed as a sintered component.

8. A method for producing a harmonic drive device, the method comprising the steps of: A pot-shaped drive element (2) is provided which is designed as a transmission element of a continuously variable transmission, wherein a first positive-fit element (44) is formed on a bottom (5) of the drive element (2). A pot-shaped externally toothed flexible transmission element (26) is provided, wherein second form-fitting elements (39, 40) are formed on the bottom (27) of the flexible transmission element (26), providing a wave generator (31) designed to deform the flexible transmission element (26), A pot-shaped internally toothed output element (4) is provided, inserting the wave generator (31) into the flexible transmission element (26), inserting the assembly (46) formed by the wave generator (31) and the flexible transmission element (26) into the output element (4), The drive element (2) is slid onto the output element (4) until a connection suitable for transmitting torque is established between the respective form-fitting elements (44; 39, 40), The output element (4) is fixed in the axial direction relative to the drive element (2) by a locking ring (12).

9. The method according to claim 8, characterized in that A sprocket (3) produced by means of forming technology is used as the drive element (2).

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