Wave gear with one transmission element

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) by changing its rotational position and connectable to the drive (12), a deformation sleeve (32) radially surrounding the wave disk (18) and deformable depending on the rotational position, with an external toothing (34) having a first number of teeth (Z1), a ring gear (44) radially surrounding the deformation sleeve (32) with an internal toothing (46) having a second number of teeth (Z2) which is coupled to the external toothing (34) depending on the rotational position, wherein either the deformation sleeve (32) or the ring gear (44) can be connected to the output (14),wherein at least one transmission element (56) which is deformable depending on the rotational position and which has an intermediate gear (58) with a third number of teeth (Z3) coupled to the external gear (34) and the internal gear (46) depending on the rotational position is arranged between the external gear (34) and the internal gear (46).

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. Further wave gears are known from DE 10 2004 043 077 B4, DE 37 38 521 C1, DE 40 30 220 A1 and DE 25 45 681 A1.

[0003] The object of the present invention is to make the transmission of the wave gear more flexible and cost-effective. The wave gear should be designed to save installation space.

[0004] At least one of these problems is solved by a wave gear with the features according to claim 1. This allows the gear ratio of the wave gear to be increased while maintaining compact dimensions. The gear ratio can be changed by modifying only a few components of the wave gear. For example, the gear ratio can be changed without altering the wave disk by changing the second number of teeth and omitting the transmission element.

[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 900 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 drive, in particular to the external teeth of the input shaft. The drive can be detachably connected to the wave disk.

[0007] The output shaft may include a flange. The deformation sleeve or the ring gear may be positively, force-, and / or materially bonded to the output shaft. The deformation sleeve or the ring gear may be detachably bonded to the output shaft. If the deformation sleeve is bonded to the output shaft, the ring gear may be fixed to the housing. If the ring gear is bonded to the output shaft, the deformation sleeve may 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 and has a principal axis. Due to the elliptical contour of the wave disk, rotation of the wave disk can cause periodic deformation of the adjacent components, in this case, the deformation sleeve. At the base of the principal axis, the wave disk can exert radial pressure on two radially opposite areas of the deformation sleeve, thereby causing elliptical deformation of the deformation sleeve, including its external teeth.

[0009] The corrugated disk 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 disk. The bearing element can be a thin-section bearing. The bearing element can be pre-mounted on the corrugated disk. The bearing element can be deformable depending on the rotational position of the corrugated disk and transmit the deformation to the deformation sleeve.

[0010] The deformation sleeve can also be referred to as a flexspline. Due to the deformation of the sleeve, the external teeth of the deformation sleeve can be partially coupled to the internal teeth of the ring gear on its circumference. In other areas on the circumference, the deformation sleeve may be uncoupled from the ring gear.

[0011] The toothed coupling can be a direct gear engagement or an indirect gear engagement via one or more radially arranged intermediate gears. The toothed coupling can be permanent, but its circumferential position can vary according to the changing rotational position. Depending on the rotational position, the circumferential positions of the toothed coupling between the transmission element, the deformation sleeve, and the ring gear can vary in the circumferential direction depending on the tooth difference between the first, second, and third sets of teeth.

[0012] A difference between the number of teeth (first and third) can constitute a first tooth asymmetry. A difference between the number of teeth (second and third) can constitute a second tooth asymmetry.

[0013] With a positive first tooth difference of 2, the deformation sleeve is rotated relative to the transmission element by, for example, two teeth of the transmission element with each revolution of the wave disk. With a positive second tooth difference of 2, the transmission element is rotated relative to the ring gear by, for example, two teeth of the ring gear with each revolution of the wave disk. With a positive total tooth difference of 4, the deformation sleeve is rotated relative to the ring gear by, for example, four teeth of the ring gear with each revolution of the wave disk.

[0014] The transmission element can effect a two-stage transmission. Firstly, it can provide a primary transmission between the deformation sleeve and the transmission element itself, and secondly, a primary transmission between the transmission element and the ring gear. The transmission element can be a transmission disc. It can be annular in shape. It can be continuous around its circumference.

[0015] The hollow gear can also be called a circular spline.

[0016] In a preferred embodiment of the invention, it is advantageous if the transmission element is arranged radially between the external and internal teeth. The transmission element can be arranged coaxially with the wave disk. The transmission element can be arranged to axially overlap the bearing element at least partially. The transmission element can be arranged to axially overlap the external and internal teeth at least partially. The transmission element can surround the deformation sleeve radially outside. The transmission element can be arranged radially inside the ring gear. The ring gear can surround the transmission element radially outside.

[0017] A preferred embodiment of the invention is advantageous in which the third number of teeth differs from the first and / or second number of teeth. The third number of teeth can be the same as the first or second number of teeth. In this case, the third number of teeth differs from the second or first number of teeth.

[0018] In a particular embodiment of the invention, it is advantageous if the third number of teeth is greater than the first number of teeth and less than or equal to the second number of teeth. The third number of teeth can be two teeth greater than the first number of teeth. The third number of teeth can be the same as the second number of teeth or two teeth less than the second number of teeth.

[0019] In a particular embodiment of the invention, it is advantageous if the intermediate toothing is toothed together with the external and internal toothing at the same circumferential position. This circumferential position can be at least one intersection point with the principal axis of the elliptical wave disk. The intermediate toothing can be toothed together with the external and internal toothing at the two radially opposite circumferential positions formed by the intersection points with the principal axis of the elliptical wave disk.

[0020] In a preferred embodiment of the invention, it is advantageous if the intermediate gearing comprises external and internal intermediate gearing. The number of teeth of the external intermediate gearing can be the same as or different from the number of teeth of the internal intermediate gearing.

[0021] In an advantageous embodiment of the invention, it is provided that, depending on the rotational position, the external intermediate teeth are meshed with the internal teeth and vice versa. At the radially opposite circumferential positions forming the points of intersection with the main axis of the elliptical wave disk, the external intermediate teeth can be meshed with the internal teeth and vice versa.

[0022] In a preferred embodiment of the invention, it is advantageous if a tooth root of the external intermediate gearing is arranged radially further inward than a tooth root of the internal intermediate gearing. The transmission element can be constructed from a thin web, and the external intermediate gearing can define the internal intermediate gearing.

[0023] In a particular embodiment of the invention, it is advantageous if the deformation sleeve and / or the ring gear have at least one circumferentially continuous annular surface area. The internal teeth of the wave disk can be independent of the external teeth of the wave disk. The internal teeth of the ring gear can be independent of a contour on an outer circumference of the ring gear. The transmission element can also have a circumferentially continuous annular surface area.

[0024] A preferred embodiment of the invention is advantageous in which, at a given rotational position, the transmission element is radially free of overlap with the deformation sleeve and / or the ring gear at a second circumferential position offset by 90° relative to a first circumferential position forming the toothed coupling. The transmission element may, at least partially, but to a lesser extent than at the first circumferential position, overlap radially with the deformation sleeve and / or the ring gear at the second circumferential position.

[0025] Further advantages and advantageous embodiments of the invention will become apparent from the description of the figures and the illustrations. Character description

[0026] The invention is described in detail below with reference to the illustrations. These show, in detail: Fig. 1: A cross-section of a wave gear in a special embodiment of the invention. Fig. 2: A side view of a wave gear in a further special embodiment of the invention.

[0027] Fig. Figure 1 shows a cross-section of 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 that is rotatable about an axis of rotation 16 by changing its rotational position and can be connected 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 22 of the wave disk 18. The bearing element 20 has a deformable first bearing ring 24 and a deformable second bearing ring 26 radially outside the first bearing ring 24. Bearing means 28, in particular rolling elements, are accommodated radially between the first and second bearing rings 24 and 26.

[0028] The elliptical contour of the wave disk 18 causes a periodic deformation of the first and second bearing rings 24, 26 during rotation of the wave disk 18. The wave disk 18 has an internal toothing (not visible here) for meshing with an external toothing of a drive shaft 29 of the drive 12. The drive 12 comprises a motor 30, in particular an electric motor.

[0029] Furthermore, the wave gear 10 comprises a deformation sleeve 32 radially surrounding the wave disk 18 and deformable depending on the rotational position. The deformation sleeve 32 has an external toothing 34 with a first number of teeth. It has an axial section 36 on which the external toothing 34 is arranged and a radial section 38 adjoining it. The radial section 38 is rigidly connected to an output flange 40 on the output side. An outer ring 42 is rigidly connected to the output flange 40 and the deformation sleeve 32.

[0030] The wave gear 10 further comprises a ring gear 44 radially surrounding the deformation sleeve 32, with an internal toothing 46 having a second number of teeth, which is coupled to the external toothing 34 depending on the rotational position. The ring gear 44 is screwed to an inner ring 47. The inner ring 47 is rotatably mounted on the outer ring 42 via a first bearing element 48 and an axially offset second bearing element 50. The first and second bearing elements 48 and 50 are each designed as angular contact needle bearings.

[0031] A sealing device 52 is arranged radially between the inner ring 47 and the outer ring 42 for sealing an interior space 54 of the wave gear 10. In the interior space 54, in particular, the bearing element 20, the wave washer 18, the first and second bearing elements 48, 50 and the deformation sleeve 32 are arranged.

[0032] A translation element 56, which is deformable depending on the rotational position, with an intermediate toothing 58 having a third number of teeth coupled to the external toothing 34 and the internal toothing 46 depending on the rotational position, is arranged between the external toothing 34 and the internal toothing 46. The translation element 56 is arranged radially between the external toothing 34 and the internal toothing 46.

[0033] Fig.Figure 2 shows a side view of a wave gear in a further specific embodiment of the invention. The transmission element 56 is arranged radially between the ring gear 44 with the internal teeth 46 and the deformation sleeve 32 with the external teeth 34. The elliptical wave disk 18, rotatable about the axis of rotation 16, is arranged radially inside the deformation sleeve 32. The bearing element 20 is arranged radially between the wave disk 18 and the deformation sleeve 32. The deformation sleeve 32 and the ring gear 44 each have a circumferentially continuous annular surface area 60.

[0034] The translation element 56 comprises the intermediate gear 58 with an external intermediate gear 62 which is toothed and coupled to the internal gear 46 and with an internal intermediate gear 64 which is toothed and coupled to the external gear 34.

[0035] A rotational movement of the wave disk 18, occurring while its rotational position is changed, deforms the deformation sleeve 32 with the external teeth 34, and this in turn deforms the transmission element 56. This results in the external intermediate teeth 62 being toothed together with the internal teeth 46, and the internal intermediate teeth 64 being toothed together with the external teeth 34, at two radially opposite first circumferential positions 66 along the main axis 68 of the wave disk 18, which is dependent on the rotational position. At the first circumferential positions 66, the intermediate teeth 58 are toothed together with the external teeth 34 and the internal teeth 46. At the second circumferential positions 70, which are offset by 90° from the first circumferential positions 66 forming the toothed coupling, the transmission element 56 is radially free of overlap with the deformation sleeve 32 and the ring gear 44.

[0036] The third tooth configuration Z3 has 52 teeth, unlike the first tooth configuration Z1 with 50 teeth and the second tooth configuration Z2 with 54 teeth. Therefore, the third tooth configuration Z3 is larger than the first tooth configuration Z1 and smaller than the second tooth configuration Z2. This allows the gear ratio of the wave gear to be increased, in this case doubled, by the gearing element 56, compared to using no gearing element 56 and a second tooth configuration of 52 teeth.

[0037] The translation element 56 is constructed from a thin web 72, and a tooth root 74 of the external intermediate gear 62 is arranged radially further inward than a tooth root 76 of the internal intermediate gear 64. The external intermediate gear 62 dictates the position of the internal intermediate gear 64. Reference symbol list 10 wave gears 12 Drive 14 Drive 16 axis of rotation 18 wave washer 20 bearing element 22 External circumference 24 first bearing ring 26 second bearing ring 28 Storage equipment 29 Drive shaft 30 engine 32 Deformation sleeve 34 External teeth 36 Axial section 38 Radial section 40 Output flange 42 Outer ring 44 Ring gear 46 Internal teeth 47 inner ring 48 first bearing element 50 second bearing element 52 Sealing device 54 Interior 56 Translation element 58 Intermediate gearing 60 area 62 External intermediate gearing 64 Internal inter-gear 66 first circumferential position 68 Main axis 70 second circumferential position 72 Steg 74 Tooth base 76 Tooth base Z1 first number of teeth Z2 second number of teeth Z3 third number of teeth

Claims

[1] Wave gear (10) for torque transmission between a drive (12) and a driven (14), comprising an elliptical wave disk (18) rotatable about a rotational axis (16) by changing its rotational position and connectable to the drive (12), a deformation sleeve (32) radially surrounding the wave disk (18) and deformable depending on the rotational position, with an external toothing (34) having a first number of teeth (Z1), a ring gear (44) radially surrounding the deformation sleeve (32) with an internal toothing (46) coupled to the external toothing (34) depending on the rotational position, having a second number of teeth (Z2), wherein either the deformation sleeve (32) or the ring gear (44) can be connected to the output (14), characterized by , that between the external toothing (34) and the internal toothing (46) at least one translation element (56) which is deformable depending on the rotational position and which has an intermediate toothing (58) with a third number of teeth (Z3) which is coupled to the external toothing (34) and the internal toothing (46) depending on the rotational position. [2] Wave gear (10) according to claim 1, characterized by , that the translation element (56) is arranged radially between the external toothing (34) and the internal toothing (46). [3] Wave gear (10) according to claim 1 or 2, characterized by , that the third number of teeth (Z3) differs from the first and / or second number of teeth (Z1, Z2). [4] Wave gear (10) according to any one of the preceding claims, characterized by , that the third number of teeth (Z3) is greater than the first number of teeth (Z1) and less than or equal to the second number of teeth (Z2). [5] Wave gear (10) according to any one of the preceding claims, characterized by , that the intermediate toothing (58) is toothed and coupled to the external toothing (34) and the internal toothing (46) at the same circumferential position. [6] Wave gear (10) according to any one of the preceding claims, characterized by , that the intermediate toothing (58) has an external intermediate toothing (62) and an internal intermediate toothing (64). [7] Wave gear (10) according to claim 6, characterized by , that depending on the rotational position the external intermediate gear (62) is coupled to the internal gear (46) and the internal intermediate gear (64) is coupled to the external gear (34). [8] Wave gear (10) according to claim 6 or 7, characterized by , that a tooth root of the external intermediate toothing (62) is arranged radially further inwards than a tooth root (76) of the internal intermediate toothing (64). [9] Wave gear (10) according to any one of the preceding claims, characterized by, that the translation element (56) is radially free of overlap with the deformation sleeve (32) and / or the ring gear (44) at a given rotational position at a second circumferential position (70) offset by 90° relative to a first circumferential position (66) forming the toothed coupling.

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