Reduction Gearbox

Abstract

The invention relates to a reduction gearbox (21) comprising a flexible ring element (2) with an external toothing (3) which is locally radially deformable in the circumferential direction by a wave generator (1) with a non-circular outer circumferential surface (6) and a rigid ring element (4) with an internal toothing (5). The external toothing (3) of the flexible ring element (2) at least partially meshes with the internal toothing (5) of the rigid ring element (4) for transmitting torque in at least one meshing engagement region (8), the wave generator (1) having a non-circular first inner ring (9) which at least partially projects into the flexible ring element (2) and is rotatably fixed to a shaft (10). The reduction gearbox (21) additionally comprises a first bearing element (11) with a second inner ring (12) and at least one first outer ring (13a), the second inner ring (12) being fixed to the rigid ring element (4). Each outer ring (13a) is fixed to a flexible ring element (). Additionally, a drive cover (14) is provided which is fixed to the generally radially extending portion (2a) of the flexible ring element (2), the drive cover (14) being equipped with at least one opening (15) on which a diaphragm (16) is arranged to equalize gas pressure and / or temperature differences between the interior (17) of the reduction gearbox and the surroundings (18) of the reduction gearbox.

Description

[Technical field]

[0001] The present invention relates to a reduction gearbox for a robot. The present invention further relates to a robot comprising such a reduction gearbox. [Background technology]

[0002] DE 112012000058 A1 discloses a reduction gearbox with a fixed internal gear wheel, a flexible external gear wheel arranged in the fixed internal gear wheel, and a wave generator. The wave generator deflects the flexible external gear wheel into an elliptically shaped configuration and partially meshes with the fixed internal gear. Furthermore, the wave generator moves the engagement position of the two gears in the circumferential direction. The flexible external gear wheel has a cylindrical drum part with an open edge at one end and capable of deflecting in the radial direction. The cylindrical drum part has an outer toothed part with an outer toothed part formed thereon and a pressed part which is pressed in the radial direction by the wave generator so as to deflect the outer toothed part into an elliptically shaped configuration. The outer toothed part and the pressed area are formed in different areas of the cylindrical drum part in the central axial direction of the flexible external gear wheel. The wave generator is disposed on the outside of the cylindrical drum portion and presses the pressed portion from the outside to the inside in the radial direction so as to bend the pressed portion into an elliptical shape. Summary of the Invention [Problem to be solved by the invention]

[0003] The object of the present invention is to further develop reduction gearboxes, in particular to improve the service life of wear parts of reduction gearboxes. This object is achieved according to a first aspect of the invention by the subject matter of claim 1 and according to a second aspect of the invention by the subject matter of claim 5. Preferred embodiments can be found in the dependent claims, the description and the drawings. [Means for solving the problem]

[0004] The reduction gearbox comprises a flexible ring element, which is radially deformable locally in the circumferential direction by a wave generator having a non-circular outer circumferential surface and comprises an outer toothing, and a rigid ring element having an inner toothing, the outer toothing of the flexible ring element at least partially meshing with the inner toothing of the rigid ring element for transmitting torque in at least one meshing engagement region, the wave generator has a non-circular first inner ring protruding at least partially into the flexible ring element and rotatably fixedly connected to the shaft, the reduction gearbox additionally comprises a first bearing element comprising a second inner ring and at least one first outer ring, the second inner ring being fixed to the rigid ring element, each outer ring being fixed to the flexible ring element, and additionally provided with a drive cover fixed to a generally radially extending portion of the flexible ring element, for example the wave generator and thus also the first inner ring having an elliptical or oval cross-sectional shape. The drive cover preferably covers the flexible ring element from the input side.

[0005] According to a first aspect of the invention, the drive cover is equipped with at least one opening over which a diaphragm is arranged to equalize gas pressure and / or temperature differences between the interior of the reduction gearbox and the surroundings of the reduction gearbox.

[0006] Each opening connects the interior of the reduction gearbox with the external environment of the gear. The openings are to be understood as recesses or holes, and the diaphragms completely cover the corresponding openings. Each opening extends essentially axially through the respective component in which it is formed. The interior of the reduction gearbox described here is spatially separated from the external environment of the reduction gearbox, the interior being only pneumatically and / or thermally connected to the environment of the reduction gearbox, in particular the external atmosphere, via the respective diaphragms arranged in the corresponding openings. In this context, "pneumatically connected" means that pressure equalization between the two spaces is possible via the respective diaphragms. In this context, "thermally connected" means that temperature equalization between the two spaces is possible via the respective diaphragms. At the same time, the respective diaphragms separate the interior of the reduction gearbox from the external environment of the reduction gearbox in such a way that neither liquid nor solid substances can pass from one area to the other.

[0007] The reduction gearbox generates heat when switching from speed to torque, causing the internal temperature of the reduction gearbox to rise. The internal pressure of the reduction gearbox also rises. A small amount of heat is dissipated to the outside through the housing or the contact surfaces of each part. The remaining heat is released to the outside through the respective diaphragms and corresponding openings. This prevents an undesirable increase in the internal pressure of the reduction gearbox, which in turn causes additional stress to the seals and bearings of the reduction gearbox. That is, the durability of the seals and bearings of the reduction gearbox is definitely affected by the respective diaphragms.

[0008] The temperature rise and / or pressure rise of the lubrication of the components inside the reduction gearbox, which are movable and / or rotatable relative to one another, is suppressed by the diaphragm. The diaphragm also separates the interior and the surrounding liquid and / or solid media, i.e. the ingress and / or inflow of foreign matter from the exterior to the interior of the reduction gearbox is prevented. In the opposite direction, the diaphragm is configured so that substances from the interior of the reduction gearbox, in particular oil or grease, cannot leak out through the respective openings.

[0009] According to one embodiment, the respective openings and diaphragms are constructed and arranged in such a way that a temperature rise and / or a pressure rise in the lubricant chamber is suppressed, i.e. a temperature and / or pressure equalization between the interior of the reduction gearbox and the surroundings is performed via the respective diaphragms. In this case, the interior should be understood as the space inside the reduction gearbox in which the parts of the reduction gearbox that are rotatable relative to one another are arranged and are mounted and supported so that they can rotate relative to one another via the respective bearings. The interior of the reduction gearbox should therefore be understood as the lubrication chamber in which the aforementioned bearings of the reduction gearbox are supplied with a lubricant, in particular a lubricating grease. In other words, the interior in this case is the space filled with a lubricant.

[0010] The diaphragm is a diaphragm filter, the diaphragm being preferably made of an aluminum ceramic, for example including aluminum oxide and silicon oxide. The diaphragm has an indeterminate number of fine holes, the narrowly distributed holes preferably having a hole diameter of approximately 0.1-50 μm. The diaphragm is constructed such that the holes are not deformed by temperature and / or pressure. In addition, the diaphragm is heat resistant and mechanically stable. The diaphragm is also chemically resistant.

[0011] The wave generator is operatively connected to the shaft, which is preferably at least indirectly driven by an electric machine to rotate the wave generator. For example, the wave generator, in particular the first inner ring, has an elliptical or oval cross-sectional shape. The first inner ring and the shaft are preferably two separate components, the first inner ring being for example pressed onto the shaft to form a rotatably fixed connection. The shaft can also be connected to the first inner ring in a rotatably fixed manner via a drive toothing. Alternatively, it is conceivable to form the first inner ring and the shaft as a single part. The wave generator forms the drive of the reduction gearbox and, in the case of a two-part configuration of the shaft and the first inner ring, is preferably pressed into a flexible, i.e. elastically deformable, ring element together with the associated bearing element. The shaft can be configured as a hollow shaft, i.e. a solid shaft.

[0012] The flexible ring element, also called "flexspline", is a high-strength, torsion-resistant sleeve element. It is configured to be flexible so that it can at least partially accommodate the wave generator in the axial direction and thus be locally deformable according to the geometry of the wave generator. The wave generator is rotatably mounted relative to the flexible ring element or slidably mounted therein. The flexible ring element thus assumes the non-circular shape of the wave generator and elastically deforms in a generally radial direction similar to the direction of rotation of the wave generator. That is to say, the wave generator is caused to move in a rotational manner during operation of the reduction gearbox, which causes a circumferential deformation in the flexible ring element.

[0013] Preferably, the external toothing of the flexible ring element for transmitting torque is at least partially in meshing engagement with the internal toothing of the rigid ring element in two meshing engagement regions symmetrically opposed to the axis of rotation of the wave generator.

[0014] Preferably, a number of rolling elements are arranged at a distance from each other between the outer circumferential surface of the inner ring and the inner circumferential surface of the flexible ring element, i.e. the elastic ring element is the outer ring and the rolling elements roll spatially between the inner and outer rings. Alternatively, the wave generator may have an additional outer ring arranged radially between the rolling elements and the flexible ring element. In this case, during assembly, the outer ring of the wave generator contacts the inner circumferential surface of the flexible ring element. This simplifies both the handling and the assembly of the wave generator parts.

[0015] The rigid ring element, also called a "circular spline", is a torsion-resistant rigid ring whose inner toothing has more teeth than the outer toothing of the flexible ring element. Rotation of the wave generator causes a permanent circumferential meshing engagement between the flexible ring element and the rigid ring element, i.e. the opposing meshing engagement areas move continuously around the axis of rotation of the wave generator, i.e. in the circumferential direction, during rotation of the wave generator. Since the flexible ring element has fewer teeth than the rigid ring element, rotation of the wave generator causes a relative movement of the flexible ring element with respect to the rigid ring element. The rolling element rolls between the inner ring and the flexible ring element, i.e. the outer ring of the wave generator.

[0016] During operation, the wave generator rotates, whereby the first inner ring of the wave generator is twisted relative to the flexible ring element, i.e. the outer ring of the wave generator, which is accommodated in the wave generator in a separately rotatably fixed manner. The flexible ring element deforms elastically in a manner similar to the direction and speed of rotation of the wave generator. That is to say, the wave generator is subjected to a rotational movement during operation of the reduction gearbox, which rotational movement causes a circumferential deformation in the flexible ring element. The first inner ring of the wave generator and the flexible ring element, i.e. the outer ring, if present, form the second bearing element of the reduction gearbox.

[0017] The shaft is preferably configured to be rotatably mounted relative to the robot arm segment, in particular the output flange, via the third bearing element. The shaft can be configured as an at least partially hollow shaft, i.e. a solid shaft, and the third bearing element is arranged radially inside the shaft. In contrast to the first and second bearing elements, the third bearing element is preferably a floating bearing and allows rotation of the shaft relative to another part, in particular the robot arm segment or the output flange.

[0018] The diaphragm is preferably connected to the drive cover in such a way that it is materially bonded to the drive cover. The diaphragm is preferably glued to the inside of the drive cover facing the inside. This improves the sealing effect of the diaphragm and effectively protects the inside of the reduction gearbox from external influences, in particular from undesirable solid and / or liquid substances. The material-fixed connection between the diaphragm and the associated component can be realized by means of a double-sided coated tape.

[0019] According to a further embodiment, the interior is divided into different segments, on the one hand into a space filled with lubricant, i.e. a lubricated region, and at least one further segment sealed off from the lubricated region. The further segment can be provided for accommodating at least a part of the electronics of the reduction gearbox. In this case, the diaphragm additionally suppresses the temperature rise and / or pressure rise of components or elements arranged in the further interior segment.

[0020] In this sense, the drive cover is configured to accommodate the torque sensor and / or the printed circuit board, which is located in a sensor holder in the drive cover, which is sealed from the rest of the interior of the reduction gearbox, which means that the interior of the reduction gearbox is divided into a part that holds the lubricant and a part that holds the electronic components of the reduction gearbox, and the two parts are sealed from each other.

[0021] The torque sensor mounted on the reduction gearbox has a circuit board or printed circuit board, which is located in the reduction gearbox, here on the drive cover. As already mentioned, the temperature and pressure in the reduction gearbox rise, especially during switching operations. Since the sensor and possibly also the printed circuit board are located in the reduction gearbox, the temperature of these components also rises and they are subjected to pressure. The printed circuit board of the torque sensor consists of electronic components that are affected by temperature changes, which can have a negative effect on the operation and / or lifespan of the components on the circuit board.

[0022] In this embodiment as well, a small amount of heat is dissipated to the outside through the housing or the contact surfaces of each component. The remaining heat is released to the outside through the respective diaphragms and the corresponding openings. This prevents an undesired increase in the internal pressure of the reduction gearbox, which in turn causes additional stress on the seals and bearings of the reduction gearbox. That is, the durability of the torque sensor and / or the printed circuit board is definitely influenced by the respective diaphragms.

[0023] A recess or depression, understood as a sensor holder, in which at least the printed circuit board of the torque sensor is accommodated can be provided in the drive cover. The sensor holder is also located inside the reduction gearbox, in particular on the inside of the drive cover. The sensor holder is sealed against the interior of the reduction gearbox, which is configured as a lubrication chamber, and is configured as a lubrication chamber.

[0024] In this sense, at least one seal is arranged radially between the drive cover and the flexible ring element for sealing the sensor holder from the rest of the interior of the reduction gearbox. The sealing element is preferably a lip seal.

[0025] The torque sensor and / or printed circuit board wiring may be located and secured and routed through the drive cover as required.

[0026] According to a second aspect of the invention, at least the second inner ring of the first bearing element is equipped with at least one opening, on which a diaphragm is arranged to equalize the gas pressure difference and / or temperature difference between the interior of the reduction gearbox and the surroundings of the reduction gearbox. In particular, the opening extends axially through the second inner ring, the rigid ring element and any output element arranged thereon. The output element may for example be a slowly rotating output flange. In this case, it may be necessary to provide a plurality of openings on the rotating element to achieve the desired temperature and / or pressure equalization. Furthermore, reference is made to the explanations regarding the first aspect of the invention regarding the function and effect of the diaphragm at the corresponding opening.

[0027] Such an arrangement of the respective openings is particularly suitable when the internal part of the reduction gearbox which receives the lubricant is not connected to the drive cover.

[0028] Preferably, in this embodiment, the diaphragm is connected to the second inner ring so as to be materially bonded thereto. The diaphragm is preferably bonded to the interior of the second inner ring facing inwards.

[0029] For all exemplary embodiments, the first bearing element is preferably a crossed roller bearing, comprising a second inner ring, a first outer ring, and a second outer ring arranged axially adjacent to the first outer ring. A plurality of rollers are arranged between the second inner ring and the first outer ring, spaced apart from each other. A plurality of rollers are also arranged between the second inner ring and the second outer ring, spaced apart from each other. Crossed roller bearings are advantageous against moment loads and moment stresses from all directions, including axial and radial. The rollers of the two rows of rolling elements are arranged in an X configuration.

[0030] The invention also relates to a robot comprising an inventive reduction gearbox according to the first aspect of the invention or according to the second aspect of the invention, in particular the inventive reduction gearbox is arranged at a joint of a robot arm and acts at least indirectly between two robot arm segments.

[0031] Further means for improving the invention are described in more detail below with reference to the drawings, together with a description of three preferred exemplary embodiments of the invention, in which identical or similar elements are given the same reference numerals. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 shows a simplified schematic diagram of a partially shown robot having a reduction gearbox according to the invention according to a first embodiment. [Diagram 2] 2 shows a schematic longitudinal section of the reduction gearbox according to the invention according to FIG. 1; [Diagram 3] 1 and 2 show schematic partial longitudinal cross-sectional views of a reduction gearbox according to the invention; [Figure 4] FIG. 4 shows a schematic longitudinal section of a reduction gearbox according to the invention according to a third embodiment. [Diagram 5] 5 shows a schematic partial longitudinal section of a reduction gearbox according to the invention according to FIG. 4. [Figure 6] FIG. 2 shows a highly schematic view of an opening on a drive cover of a reduction gearbox according to the invention. [Figure 7] FIG. 13 shows a schematic partial longitudinal section of a reduction gearbox according to the invention according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] 1 shows a cross section of a robot 20. Between a first robot arm segment 22a and a second robot arm segment 22b there is arranged a joint 23 which articulately connects the two robot arm segments 22a, 22b to one another. To change the position of the two robot arm segments 22a, 22b relative to one another, the robot 20 has a drive unit 24 which comprises an electric motor 25 according to the invention and a reduction gearbox 21.

[0034] According to Figures 2 to 5 and 7, the reduction gearbox 21 according to the present invention in a first embodiment comprises a flexible ring element 2 having an external toothing 3 which is radially and circumferentially deformable by a wave generator 1, and a rigid ring element 4 having an internal toothing 5, the external toothing 3 of the flexible ring element 2 meshing with the internal toothing 5 of the rigid ring element 4 for transmitting torque in two opposing meshing engagement areas 8.

[0035] The reduction gearbox 21 has a first bearing element 11 configured as a crossed roller bearing. The first bearing element 11 comprises a second inner ring 12, a first outer ring 13a and a second outer ring 13b arranged axially adjacent to the first outer ring 13a. Between the second inner ring 12 and the respective outer ring 13a, 13b a respective rolling element train is arranged with a plurality of rolling elements 28. The second inner ring 12 is fixedly mounted to the rigid ring element 4 and the outer rings 13a, 13b are fixedly mounted to the radially extending portion 2a of the flexible ring element 2.

[0036] The wave generator 1 further comprises a non-circular second bearing element 26 arranged radially between the flexible ring element 2 and the shaft 10 of the reduction gearbox 21. The second bearing element 26 has a first inner ring 9 arranged to be rotatably fixed on an outer circumferential surface 27 of the shaft 10 and a third outer ring 29 arranged radially inside the flexible ring element 2 of the reduction gearbox 21. The wave generator 1 can be moved in rotation via the shaft 10 by an electric motor (not shown here).

[0037] The first inner ring 9 and the third outer ring 29 of the non-circular, in particular elliptical, second bearing element 26 have, for example, an elliptical outer geometry, such that the outer circumferential surface of the third outer ring 29 is rotatably mounted on the inner circumferential surface of the flexible ring element 2. Before assembly of the second bearing element 26, the third outer ring 29 has an approximately circular outer geometry, which is elastically deformed during assembly into an elliptical outer geometry according to the outer geometry of the first inner ring 9. The second bearing element 26 is pressed into the flexible ring element 2 such that the wave generator 1 with the second bearing element 26 protrudes into the flexible ring element 2. The flexible ring element 2 assumes the elliptical outer shape of the wave generator 1. During operation of the reduction gearbox 21, the wave generator 1 is moved in rotation via the shaft 10, whereby the third outer ring 29 and the flexible ring element 2 are locally deformed radially. That is, rotation of the wave generator 1 about its axis of rotation 7 causes the flexible ring element 2 and the third outer ring 29 to deform in the circumferential direction.

[0038] The flexible ring element 2 is adapted to the elliptical shape of the wave generator 1, so that the flexible ring element 2 with its outer toothing 3 engages with the inner toothing 5 of the rigid ring element 4 only in the respective meshing engagement area 8. The rigid ring element 4 is to be understood in this case as a ring gear.

[0039] The reduction gearbox 21 further comprises a drive cover 14 which is fixed to the generally radially extending portion 2a of the flexible ring element 2 on the input side, i.e. on the side of the generally radially extending portion 2a opposite the outer rings 13a, 13b of the first bearing element 11.

[0040] According to figures 3 and 5, an axial opening 15 is formed on the drive cover 14, in which a diaphragm 16 is arranged. On the one hand, the diaphragm is arranged to equalise the gas pressure and temperature differences between the interior 17 of the reduction gearbox and the surroundings 18 of the reduction gearbox. Furthermore, the diaphragm 16 is provided to prevent substances, in particular lubricants, from leaking out of the reduction gearbox 21 and to prevent substances, in particular dirt and / or moisture, from entering the reduction gearbox 21.

[0041] As shown by way of example in FIG. 6, the diaphragm 16 is connected to the drive cover 14 so as to be materially bonded to it. The diaphragm 16 has a tape 16a coated on both sides with adhesive, which tape 16a is arranged between the diaphragm body 16b and the drive cover 14. The tape 16a ensures that the reduction of gas pressure and the dissipation of excess heat, i.e. equalization of gas pressure and temperature, takes place exclusively via the diaphragm body 16b. During operation of the reduction gearbox 21, in the interior 17 of the reduction gearbox 21, the temperature increases and the internal pressure increases. This is partially absorbed and dissipated via the housing (not shown here). The remaining, substantial part of the additional heat is dissipated via the diaphragm 16 and the openings 15 to the surroundings 18 of the reduction gearbox 21. The openings also facilitate pressure equalization between the interior 17 and the surroundings 18, i.e. the outside air.

[0042] According to the first embodiment according to figures 2 and 3, the interior 17 of the reduction gearbox 21 is to be understood as the lubricated area of ​​the reduction gearbox 21. The interior 17 is formed within the dashed line 30 according to figure 3 and comprises two rows of rolling elements, in this case with the rolling elements 28 of the first bearing element 11, the second bearing element 26, the third bearing element 31 which rotatably supports the shaft 10 with respect to the output flange 32 and the fourth bearing element 6 which rotatably supports the shaft 10 with respect to the drive cover 14.

[0043] According to the second exemplary embodiment shown in Fig. 4 and Fig. 5, in contrast to the first exemplary embodiment, the interior 17 of the reduction gearbox 21 is divided into two regions, on the one hand a lubrication region analogous to the first exemplary embodiment and an electronics receiving region here formed as a sensor holder 14a on the drive cover 14. Fig. 5 shows the sensor holder 14a using a dashed line 30. A printed circuit board 33 for the torque sensor is arranged in the sensor holder 14a. The sensor holder 14a is sealed from the lubrication region by a seal 19 configured as a lip seal, which is arranged radially between the axial part 14b of the drive cover 14 and the flexible ring element 2. The sensor holder 14a of the drive cover 14 is thereby sealed from the remaining interior 17 of the reduction gearbox 21, here the part of the interior 17 configured as a lubrication region. For further information, please refer to the above description.

[0044] The reduction gearbox 21 according to the third embodiment according to FIG. 7 is essentially identical to the second embodiment according to FIGS. 4 and 5. The difference here is that, analogously to the first embodiment, the sensor holder 14a is fluidically and spatially separated from the interior 17 of the reduction gearbox 21, which is configured as a lubricated area. The dashed line 30 generally surrounds the interior 17 of the reduction gearbox 21 forming the lubricated area. This spatial separation results in an opening 15 in the second inner ring 12 of the first bearing element 11, in which a diaphragm 16 is arranged, via which gas pressure and temperature equalization takes place between the interior 17 of the reduction gearbox 21 and the surroundings 18 of the reduction gearbox 21, analogously to the previous embodiment. The diaphragm 16 is connected to the second inner ring 12 in such a way that it is materially bonded. Due to this construction, the opening 15 extends axially through the second inner ring 12, the rigid ring element 4 and the output flange 32. The rigid ring element 4 and the output flange 32, being slowly rotating components, may have additional openings (not shown) distributed over their periphery to ensure sufficient heat dissipation and pressure equalization. This exemplary embodiment is intended to illustrate that each opening 15 may be located in a component of the reduction gearbox 21 other than the drive cover 14. In any case, a diaphragm 16 is provided at each opening 15, regardless of its location, to prevent exchange of material between the interior 17 and the surroundings and to provide heat dissipation to the surroundings 18 and pressure equalization between the interior 17 and the surroundings 18. [Explanation of symbols]

[0045] 1. Wave Generator 2 Flexible Ring Element 2a Radial extension 3 Outer teeth 4 Rigid ring elements 5 Inner teeth 6 Fourth bearing element 7 Rotation Axis 8 Meshing Engagement Area 9 First inner ring, i.e. the inner ring of the second bearing element 10 Shaft 11 First bearing element 12 second inner ring of the first bearing element 13a, 13b outer ring of first bearing element 14 Drive cover 14a Sensor holder on drive cover 14b Axial portion of drive cover 15 Opening 16 Diaphragm 17 Inside 18 Periphery 19 Sealing part 20. Robot 21 Reduction gearbox 22a, 22b Robot arm segments 23 Joint 24 Drive unit 25 Electric Motor 26 Second bearing element 27 Outer circumferential surface of shaft 28 rolling element of first bearing element 29 Third outer ring of second bearing element 30 Dashed Line 31 third bearing element 32 Output flange 33 Printed Circuit Board

Claims

1. A reduction gearbox (21), which is locally radially deformable in the circumferential direction by a wave generator (1) having a non-circular outer circumferential surface, comprises a flexible ring element (2) with an external toothing (3) and a rigid ring element (4) with an internal toothing (5), said external toothing (3) of said flexible ring element (2) at least partially meshing with said internal toothing (5) of said rigid ring element (4) for transmitting torque in at least one meshing engagement region (8), said wave generator (1) at least partially protruding into said flexible ring element (2). the reduction gearbox (21) additionally comprises a first bearing element (11) comprising a second inner ring (12) and at least one first outer ring (13a), the second inner ring (12) being fixedly mounted to the rigid ring element (4), each outer ring (13a) being fixedly mounted to the flexible ring element (2), and additionally comprising a drive cover (14) fixedly mounted to a generally radially extending portion (2a) of the flexible ring element (2); The reduction gearbox (21), characterized in that the drive cover (14) is equipped with at least one opening (15), on which a diaphragm (16) is arranged to equalize gas pressure and / or temperature differences between the interior (17) of the reduction gearbox (21) and the surroundings (18) of the reduction gearbox (21).

2. 2. The reduction gearbox (21) according to claim 1, characterized in that the diaphragm (16) is connected to the drive cover (14) in a materially bonded manner.

3. 3. The reduction gearbox (21) according to claim 1 or 2, characterized in that the drive cover (14) is configured to accommodate a torque sensor and / or a printed circuit board (33), the torque sensor and / or the printed circuit board (33) being arranged in a sensor holder (14a) of the drive cover (14), the sensor holder (14a) being sealed from the remaining interior (17) of the reduction gearbox (21).

4. The reduction gearbox (21) according to claim 3, characterized in that at least one sealing portion (19) is arranged radially between the drive cover (14) and the flexible ring element (2) to seal the sensor holder (14a) from the remaining interior (17) of the reduction gearbox (21).

5. A reduction gearbox (21) comprising a flexible ring element (2) which is locally radially deformable in the circumferential direction by a wave generator (1) having a non-circular outer circumferential surface (6) and which comprises an external toothing (3) and a rigid ring element (4) having an internal toothing (5), said external toothing (3) of said flexible ring element (2) at least partially meshing with said internal toothing (5) of said rigid ring element (4) for transmitting torque in at least one meshing engagement region (8), said wave generator (1) being at least partially inserted in said flexible ring element (2). the reduction gearbox (21) additionally comprises a first bearing element (11) comprising a second inner ring (12) and at least one first outer ring (13a), the second inner ring (12) being fixed to the rigid ring element (4), each outer ring (13a) being fixed to the flexible ring element (2), and additionally comprising a drive cover (14) fixed to a generally radially extending portion (2a) of the flexible ring element (2), 1. A reduction gearbox (21), characterized in that at least the second inner ring (12) of the first bearing element (11) is equipped with at least one opening (15), on which a diaphragm (16) is arranged in order to equalize gas pressure and / or temperature differences between an interior (17) of the reduction gearbox (21) and the surroundings (18) of the reduction gearbox (21).

6. 6. The reduction gearbox (21) according to claim 5, characterized in that the diaphragm (16) is connected to the second inner ring (12) in a materially bonded manner.

7. 7. The reduction gearbox (21) according to any one of claims 1 to 6, characterized in that the first bearing element (11) is a crossed roller bearing comprising the second inner ring (12), the first outer ring (13a) and a second outer ring (13b) arranged axially adjacent to the first outer ring (13a).

8. A robot (20) comprising a reduction gearbox (21) according to any one of claims 1 to 7.

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