Wave gear with a labyrinth seal

Abstract

The invention relates to a wave gear (10) for torque transmission between a drive (12) and an output (14), comprising an elliptical wave disk (18) rotatable about an axis of rotation (16) and connectable to the drive (12), a deformation assembly (30) with at least one deformation sleeve (32) with external teeth (34) that is elliptically deformable depending on the rotational movement of the wave disk (18), a connecting assembly (42) with at least one ring gear (44) with internal teeth (48) that engage in tooth mesh (46) with the external teeth (34) depending on the deformation of the deformation sleeve (32), and a sealing device (56) arranged between the connecting assembly (42) and the deformation assembly (30), wherein either the deformation assembly (30) or the connecting assembly (42) is rotatable about the axis of rotation (16) and connected to the output (14). connectable, wherein the sealing device (56) is designed as a labyrinth seal (64),with at least one first sealing element (66) associated with the connecting assembly (42) and at least one second sealing element (68) rotatable relative to the first sealing element (66) and associated with the deformation assembly (30).

Description

[0001] The invention relates to a wave gear according to the preamble of claim 1.

[0002] DE 10 2016 220 454 A1 describes a wave gear with a wave generator having an elliptical contour, a deformation sleeve with external teeth that is deformable depending on a rotational movement of the elliptical contour, and a ring gear that engages with it via internal teeth. A sealing device is arranged between a housing and the deformation sleeve.

[0003] The object of the present invention is to reduce the friction of the wave gear. Furthermore, the influence of temperature on the friction of the wave gear is to be reduced.

[0004] At least one of these tasks is solved by a wave gear with the features according to claim 1. This allows the friction of the wave gear to be reduced and the efficiency of the wave gear to be increased.

[0005] The wave gear can be installed in a vehicle, robot, tool, machine tool, servo motor, or industrial device. The wave gear enables transmission with large gear ratios between the input and output. For example, the maximum torque that can be transmitted between the input and output via the wave gear can range from 10 to 500 Nm. The wave gear can include a torque sensor for measuring torque, particularly the transmitted torque between the input and output.

[0006] The drive can include an input shaft. The drive can have external teeth for connection to the wave disk. The wave disk can have internal teeth for connection to the external teeth of the input shaft. The drive can be detachably connected to the wave disk.

[0007] The output shaft can include a flange. The deformation assembly or the connection assembly can be positively, force-, and / or materially bonded to the output shaft. The deformation assembly or the connection assembly can be detachably bonded to the output shaft. If the deformation assembly can be bonded to the output shaft, it can form an output shaft assembly. In this case, the connection assembly can be fixed to the housing. If the connection assembly can be bonded to the output shaft, it can form an output shaft assembly. In this case, the deformation assembly can be fixed to the housing.

[0008] The wave disk can also be called a wave generator. Viewed from above, the elliptical wave disk has an elliptical contour that deviates from a circular shape, with a principal axis of the ellipse. Due to the elliptical contour of the wave disk, rotation of the disk can cause periodic deformation of the adjacent components, such as the deformation sleeve. At the base of the principal axis, the wave disk can exert radial pressure on two opposing areas of the deformation sleeve, thereby causing elliptical deformation of the sleeve, including its external teeth.

[0009] The corrugated disc can be rotatable relative to the deformation sleeve via at least one bearing element. The bearing element can have bearing means that are received on at least one radially deformable bearing ring. The bearing means can be rolling elements, in particular balls. The bearing ring can be deformable by its elliptical contour depending on the rotational movement of the corrugated disc. The bearing element can be a thin-section bearing. The bearing element can be pre-assembled on the corrugated disc.

[0010] The deformation sleeve can also be referred to as a flexspline. The external teeth of the deformation sleeve can have a first number of teeth, and the internal teeth of the ring gear can have a second number of teeth, which differ from the first number of teeth. The first number of teeth is preferably smaller than the second number of teeth. A difference between the second number of teeth and the first number of teeth constitutes a tooth difference.

[0011] The external teeth of the deformation sleeve can engage with the internal teeth of the ring gear only partially, i.e., only partially on the circumference, due to the deformation of the deformation sleeve. This engagement can be continuous but spatially alternating. During rotation of the wave disk, the spatial areas of engagement between the deformation sleeve and the ring gear can shift circumferentially, depending on the tooth difference. For example, with a positive tooth difference of 2, the deformation sleeve is rotated relative to the ring gear by two teeth with each revolution of the wave disk.

[0012] The hollow gear can also be called a circular spline.

[0013] The first and second sealing elements are preferably non-contacting with each other. This reduces the friction of the wave gear. The first sealing element can be permanently connected to the connecting assembly, in particular by positive locking, force-fit, and / or material bonding. The second sealing element can be permanently connected to the deformation assembly, in particular by positive locking, force-fit, and / or material bonding.

[0014] In a preferred embodiment of the invention, it is advantageous if the first sealing element has at least one radial annular gap and the second sealing element has at least one radial ring engaging in the annular gap. The radial ring can extend radially inward from an axial section of the second sealing element. The annular gap can be formed by two axially spaced radial projections that span the annular gap axially between them.

[0015] The second sealing element can also have at least one radial annular gap and the first sealing element can have at least one radial ring engaging in the annular gap.

[0016] A preferred embodiment of the invention is advantageous in which the first sealing element has at least two axially offset annular gaps and the second sealing element has axially offset radial rings that engage in the annular gaps. Alternatively, the second sealing element may have at least two axially offset annular gaps and the first sealing element may have axially offset radial rings that engage in the annular gaps.

[0017] In a preferred embodiment of the invention, the sealing device is arranged axially, at least partially overlapping the gear mesh. The sealing device can be arranged radially outside the gear mesh.

[0018] In a preferred embodiment of the invention, it is advantageous if the deformation assembly and the connection assembly are rotatably mounted relative to each other via at least one bearing element. The bearing element can be a rolling bearing, in particular an angular contact needle bearing. The deformation assembly and the connection assembly can be rotatably mounted relative to each other via at least two bearing elements. The two bearing elements can be axially offset from each other. The two bearing elements can be arranged radially overlapping each other. The bearing element can be arranged at least partially axially overlapping the wave washer.

[0019] In a specific embodiment of the invention, it is advantageous if the sealing device is arranged to overlap the bearing element at least partially in a radial manner. This allows the wave gear to be designed in a more radially compact form.

[0020] In a preferred embodiment of the invention, it is advantageous if the sealing device is arranged axially offset from the bearing element. Further components axially between the sealing device and the bearing element are unnecessary.

[0021] In an advantageous embodiment of the invention, the sealing device is arranged to overlap the wave disk at least partially axially. This allows the wave gear to be designed more compactly in axial terms.

[0022] A preferred embodiment of the invention is advantageous in which the sealing device seals an inner area that encloses the gear mesh and can be filled with a lubricant. The gear mesh between the internal and external gears, which is lubricated by the lubricant, can be operated with low wear. The lubricant can be grease or oil.

[0023] In a preferred embodiment of the invention, the connecting assembly comprises an outer ring and the deformation assembly comprises an inner ring radially outside the outer ring, and the sealing device is arranged radially between the outer ring and the inner ring. The outer ring can be connected to a housing or the output shaft. The inner ring can be rigidly connected to a housing or the output shaft. The inner ring can be positively, force-, and / or materially connected to the deformation sleeve. The connecting means for connecting the inner ring to the deformation sleeve can be arranged radially outside the sealing device.

[0024] Further advantages and advantageous embodiments of the invention will become apparent from the description of the figures and the illustrations. Character description

[0025] The invention is described in detail below with reference to the illustrations. These show, in detail: Fig. 1: A partial cross-section of a drive device with a wave gear in a special embodiment of the invention. Fig. 2: A cross-section of a wave gear in a further special embodiment of the invention.

[0026] Fig. Figure 1 shows a partial cross-section of a drive device with a wave gear in a specific embodiment of the invention. The wave gear 10 is arranged for torque transmission between a drive 12 and an output 14 and comprises an elliptical wave disk 18 rotatable about an axis of rotation 16 and connectable to the drive 12. The wave disk 18 can also be referred to as a wave generator. A bearing element 20 is pre-assembled on an outer circumference of the wave disk 18. The bearing element 20 has a deformable first bearing ring 22 and a deformable second bearing ring 24. Bearing means 26, in particular rolling elements, are accommodated radially between the first and second bearing rings 22, 24.

[0027] The elliptical contour of the wave disk 18 causes a periodic deformation of the first and second bearing rings 22, 24 during rotation of the wave disk 18. The wave disk 18 has internal teeth (not visible here) for meshing with external teeth of the drive 12. The drive 12 comprises a motor 28, in particular an electric motor.

[0028] Furthermore, the wave gear 10 comprises a deformation assembly 30 with at least one deformation sleeve 32, which is elliptically deformable depending on the rotational movement of the wave disk 18 and is connectable to the output 14 and rotatable about the axis of rotation 16, and has external teeth 34. The deformation sleeve 32 has an axial section 36 on which the external teeth 34 are arranged and a radial section 38 adjoining it. The radial section 38 is rigidly connected to an output flange 40.

[0029] The wave gear 10 further comprises a connecting assembly 42 with at least one ring gear 44 having an internal toothing 48 which engages with the external toothing 46 depending on the deformation of the deformation sleeve 32. The connecting assembly 42 includes an outer ring 50 which is rigidly connected to the ring gear 44. The deformation assembly 30 is rotatably mounted relative to the connecting assembly 42 by a first bearing element 52 and a second bearing element 54. The first and second bearing elements 52 and 54 are each designed as angular contact needle bearings.

[0030] A sealing device 56 is arranged between the connecting assembly 42 and the deformation assembly 30. The deformation assembly 30 comprises an inner ring 58 rigidly connected to the deformation sleeve 32, and the sealing device 56 is arranged radially between the inner ring 58 and the outer ring 50. The sealing device 56 seals an inner area 60, which has a toothed section 46 and can be filled with a lubricant.

[0031] A housing 62 of the drive 12 is rigidly connected to the ring gear 44 and thus to the connecting assembly 42. The ring gear 44 is in turn rigidly connected to the outer ring 50.

[0032] Fig.Figure 2 shows a cross-section of a wave gear in a further specific embodiment of the invention. The sealing device 56 is designed as a labyrinth seal 64 with a first sealing element 66 associated with the connecting assembly 42 and a second sealing element 68 rotatable relative to the first sealing element 66 and associated with the deformation assembly 30. The first sealing element 66 has two axially offset annular gaps 70, and the second sealing element 68 has axially offset radial rings 72 that engage in the annular gaps 70. The annular gaps 70 are non-contacting with the radial rings 72. The first sealing element 66 has a first axial section 74 from which a total of three radial projections 76 extend radially outward and span the annular gaps 70 axially between them. The second sealing element 68 has a second axial section 78 from which the two radial rings 72 extend radially inward.

[0033] The first sealing element 68 is attached to an outer circumference 80 of the outer ring 50 via the first axial section 74. The second sealing element 68 is attached to an inner circumference 82 of the inner ring 58 via the second axial section 78.

[0034] The sealing device 56 is arranged axially at least partially overlapping the toothed engagement 46 and partially radially overlapping and radially offset from the bearing element 20. Furthermore, the sealing device 56 is arranged axially at least partially overlapping the wave washer 18. Reference symbol list 10 wave gears 12 Drive 14 Drive 16 axis of rotation 18 wave washer 20 bearing element 22 first bearing ring 24 second bearing ring 26 Storage equipment 28 engine 30 Deformation assembly 32 Deformation sleeve 34 External teeth 36 Axial section 38 Radial section 40 Output flange 42 Connection assembly 44 Ring gear 46 Gear engagement 48 Internal teeth 50 outer ring 52 first bearing element 54 second bearing element 56 Sealing device 58 inner ring 60 Indoor area 62 cases 64 Labyrinth seal 66 first sealing element 68 second sealing element 70 annular gap 72 Radial ring 74 first axial section 76 radial lead 78 Axial section 80 external circumference 82 inner circumference QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2016 220 454 A1

[0002]

Claims

[1] Wave gear (10) for torque transmission between a drive (12) and a driven (14), comprising an elliptical wave disk (18) rotatable about an axis of rotation (16) and connectable to the drive (12), a deformation assembly (30) with at least one deformation sleeve (32) that is elliptically deformable depending on the rotational movement of the wave disk (18) and has an external toothing (34), a connecting assembly (42) with at least one ring gear (44) with an internal toothing (48) which is in tooth engagement (46) with the external toothing (34) depending on the deformation of the deformation sleeve (32), a sealing device (56) arranged between the connecting assembly (42) and the deformation assembly (30), wherein either the deformation assembly (30) or the connection assembly (42) is rotatable about the axis of rotation (16) and connectable to the output (14), characterized by , that the sealing device (56) is designed as a labyrinth seal (64), with at least one first sealing element (66) assigned to the connection assembly (42) and at least one second sealing element (68) rotatable relative to the first sealing element (66) and assigned to the deformation assembly (30). [2] Wave gear (10) according to claim 1, characterized by , that the first sealing element (66) has at least one radial annular gap (70) and the second sealing element has at least one radial ring (72) engaging in the annular gap (70). [3] Wave gear (10) according to claim 1 or 2, characterized by , that the first sealing element (66) has at least two axially offset annular gaps (70) and the second sealing element has axially offset radial rings (72) that engage in the annular gaps (70). [4] Wave gear (10) according to any one of the preceding claims, characterized bythat the sealing device (56) is arranged axially at least partially overlapping the toothed engagement (46). [5] Wave gear (10) according to any one of the preceding claims, characterized by , that the deformation assembly (30) and the connection assembly (42) are rotatably mounted relative to each other via at least one bearing element (20). [6] Wave gear (10) according to any one of the preceding claims, characterized by that the sealing device (56) is arranged at least partially radially overlapping with the bearing element (20). [7] Wave gear (10) according to any one of the preceding claims, characterized by that the sealing device (56) is arranged axially offset to the bearing element (20). [8] Wave gear (10) according to any one of the preceding claims, characterized by that the sealing device (56) is arranged at least partially axially overlapping the wave disk (18). [9] Wave gear (10) according to any one of the preceding claims, characterized by , that the sealing device (56) seals an inner area (60) which includes the tooth engagement (46) and can be filled with a lubricant. [10] Wave gear (10) according to one of the preceding claims, characterized by , that the connecting assembly (42) comprises an outer ring (50) and the deformation assembly (30) comprises an inner ring (58) radially outside of the outer ring (50) and the sealing device (56) is arranged radially between the outer ring (50) and the inner ring (58).

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