Patent ID: 12215767

Identical parts are provided with the same reference numerals in all of the figures.

DETAILED DESCRIPTION

FIG.1shows an embodiment of a first preferred embodiment of an inventive rotary bearing50and a strain wave gear40mounted therein, together forming a gearbox70, shown in a mounted state in a sectional view. In this context, a transmission component4configured as a flexspline is placed onto an input component2that is configured as an elliptical wave generator and that is preferably mounted on a hollow shaft, wherein the transmission component4is likewise elliptically deformed by the elliptical input component2. External teeth3of the elliptically deformed transmission component4engage in the opposing areas of the major axis of the ellipse with the internal teeth5of a wheel6configured as a circular spline.

The wheel6displays the greatest axial extension of all of the components of the gear box70. In the embodiment described here, the input component2is configured as an elliptical wave generator. The elastic transmission component4configured as a flexspline is placed onto this input component2over a ball bearing16containing several balls17. Due to the elasticity in the area of its external teeth3, this transmission component4is likewise elliptically deformed owing to the elliptical shape of the input component2.

Since the elastic transmission component4has external teeth3and is elliptically deformed, these external teeth3engage in the area of the major axis of the ellipse with the internal teeth5of the wheel6configured as a circular spline. This wheel6has an internal surface that is configured as a bearing surface9and that matches an external surface of an inner bearing ring1aconfigured as a bearing surface7. This inner bearing ring1ahas internal teeth having the same number of teeth as the transmission component4, thus having the function of a clutch (without speed reduction).

In this context, an anti-friction bearing having several rolling elements8is arranged between these two bearing surfaces7and9of the wheel6and of the inner bearing ring1a, wherein these two bearing surfaces7and9of the wheel6and of the inner bearing ring1aare configured as raceways12for the rolling elements8of the anti-friction bearing. The wheel6is an outer bearing ring1bof the rotary bearing50.

In order to attain a very narrow and compact design for the gearbox70, a receptacle10in inserted into the bearing surface7of the wheel6or of the outer bearing ring1b, and a receptacle11is inserted into the bearing surface9of the inner bearing ring1a. In this context, both receptacles10and11correspond in such a way that, at an appropriate orientation relative to each other, they form a loading channel24having a receptacle opening22and can accommodate a rolling element with a positive fit. Thanks to this positive-fit accommodation of a rolling element8, the anti-friction bearing can be filled between the wheel6and the bearing ring1with rolling elements8via the loading channel24, so that the wheel6can be supported relative to the bearing ring1awithout backlash, and the bearing ring1aand the wheel6can be rotated relative to each other. In this position, it is then possible, by means of the input component2configured as a wave generator, to drive the transmission component4configured as a flexspline, so that there is a relative movement between the wheel6and the transmission component2. In the present embodiment, the rolling elements8are configured as balls.

The flexspline or the transmission component4engages with the wheel6or with the circular spline and also engages with a clutching wheel13or with a dynamic spline, wherein the clutching wheel is identical to the bearing ring1awhich has internal teeth. The clutching wheel13has internal teeth having the same number of teeth as the external teeth3of the transmission component4. In this manner, the clutching wheel13functions as a clutch without a speed reduction ratio.

The components of the gearbox70, namely, the inner bearing ring1a, the input component2, the transmission component4and the wheel6are coaxially arranged around an x-axis15of the gearbox70. Thanks to the positive-fit configuration of the rolling elements8and of the receptacles10and11of the wheel6and of the inner bearing ring1a, it is now possible to put forward a gearbox70which is very compact and narrow in the axial direction and which is especially used when there is very little installation space for the execution of rotational movements, as is the case in many applications in robotics and prosthetics, which translates into a simple installation assembly of the gearbox70.

The rotary bearing50is optimized in terms of a high degree of reliability and service life. For purposes of preventing the rolling elements8from falling out of the loading channel24or out of the receptacles10,11, a guide ring20is arranged in the receptacle10of the bearing ring1b. Receptacles10,11are likewise present in the embodiments of the rotary bearing according toFIGS.5and6.

The guide ring20, the receptacles10,11and the loading channel24are depicted inFIG.1in an enlarged view80. In the axial direction between the guide ring20and the receptacle opening22, a rotary shaft seal21is arranged in the loading channel24in order to prevent axial movement of the guide ring20in the direction of the receptacle opening22. The guide ring20has an annular projection41that runs axially and that comes into contact with the rolling elements8. The projection41preferably has a small contact surface which the rolling elements8touch during operation of the rolling elements8in order to keep the friction between the guide ring20and the rolling elements8to a minimum.

The rotary shaft seal, which is configured as a rotary shaft sealing ring, supports itself radially outside on a shoulder43inside the outer bearing ring1band, on the opposite side, its sealing edge45rests on and seals a lateral surface—configured as a sealing surface44—of the inner bearing ring1a.

In this manner, the guide ring20holds the rolling elements8in an annular gap23and prevents their falling out of the loading channel24, even if the rotary bearing50is moved or rotated, so that even if the loading channel24has a perpendicular orientation downwards, the rolling elements8do not fall out of the annular cavity23. The guide ring20here is preferably made of plastic (inexpensive) or else of steel.

The gearboxes70shown inFIGS.2to4differ from each other only regarding the type of configuration of the guide ring20or of the receptacles10,11and of the components arranged therein.

FIG.2shows another preferred embodiment of a gearbox70with a rotary bearing50and a strain wave gear40. In this embodiment, a retaining ring25is arranged in the receptacle10. The retaining ring25is arranged in a radial external area in a radial groove26in the wheel6, as a result of which, it is secured radially and axially. It prevents axial movement of the guide ring20in the direction of the receptacle opening22. The guide ring25here is preferably made of plastic or else of steel. A rotary shaft seal21is likewise present in this embodiment.

Another preferred embodiment of a gearbox70with a rotary bearing50and a strain wave gear40is shown inFIG.3. In this embodiment, the guide ring20, preferably made of steel, is configured with a helical shape and has an external thread27which engages with a matching internal thread28in the wheel6.

FIG.4shows another preferred embodiment of a gearing installation set70, having a rotary bearing50and a strain wave gear40. In this context, the guide ring20, which is preferably made of plastic but which can also be made of steel, is axially secured on its outer diameter in the wheel6by means of a press fit or interference fit. It is likewise possible to glue the guide ring.

FIG.5shows another preferred embodiment of a gearbox70, with a rotary bearing50and a strain wave gear40, having a wheel6configured as an internal gearwheel or circular spline which, in the area of its internal teeth5overlaps, and is engaged in some places, with the external teeth3of a transmission component4or flexspline.

The transmission component4is non-rotatably joined to an outer bearing ring1bof a rotary bearing50, said ring holding the transmission component4and the wheel6in such a way that they can rotate with respect to each other. An inner bearing ring1aof the rotary bearing50is non-rotatably joined to the circular spline or wheel6.

The transmission component4is elliptically deformed by an elliptical input component2. By means of its external teeth3, the elliptically deformed transmission component4engages with the opposing areas of the major axis of the ellipse into inner teeth5of a wheel6configured as a circular spline. In the embodiment described here, the input component2is configured as an elliptical wave generator. The elastic transmission component4configured as a flexspline is placed onto this input component2over a ball bearing16containing several balls17. Due to the elasticity in the area of its external teeth3, this transmission component4is likewise elliptically deformed owing to the elliptical shape of the input component2.

In this embodiment, the guide ring20is configured as an internal seal or flat seal, or else it is integrated therein. The flat seal and the guide ring20are configured as one part or in one piece. The guide ring20in this embodiment is preferably made of a composite material that preferably consists of elastomer and plastic or steel.

Another preferred embodiment of a gearbox70with a rotary bearing50and a strain wave gear40is shown inFIG.6which differs from the embodiment shown inFIG.5only in terms of the configuration of the guide ring. In this context, only a guide ring20without dynamic sealing is provided. The guide ring20here can consist purely of a plastic ring or else of a composite material in the form of elastomer and plastic or steel, so that it can also take over the function of a static O-ring between the bearing ring1band the transmission component4.

LIST OF REFERENCE NUMERALS

1ainner bearing ring1bouter bearing ring2input component3external teeth4transmission component5internal teeth6wheel7bearing surface8rolling elements9bearing surface10receptacle11receptacle13clutching wheel15x-axis16ball bearing17balls20guide ring21rotary shaft seal22receptacle opening23annular gap24loading channel25retaining ring26groove27external thread28internal thread40strain wave gear41projection43shoulder44sealing surface45sealing edge50rotary bearing70gearbox