DE102008001632A1 - Flex spline for harmonic drives comprises tubular section and flexible membrane which forms base of spline and holds it on shaft, membrane having foot section whose maximum axial length is four times minimum thickness of membrane - Google Patents

Abstract

The flex spline for harmonic drives comprises a tubular section (3) and a flexible membrane (5) which forms the base of the spline and holds it on the shaft (8). The membrane has a foot section (7) whose maximum axial length is four times the minimum thickness of the membrane.

Description

The The invention relates to a radially flexible Abrollbuchse for a wave gear according to the preamble of claim 1.

Radial flexible rolling bushes or flex splines for harmonic drives (harmonic drives) are for example in the WO 02/36992 A1 , of the DE 692 127 03 T3 or the DE 697 01776 T1 described. The radially flexible Abrollbuchsen serve as part of strongly reducing gear stages such corrugated or harmonic drives and as an output member or are rotatably disposed in such corrugations. The radially flexible Abrollbuchse is cup-shaped and formed essentially of a tubular, thin sleeve and a radially guided to the longitudinal axis of the radially flexible Abrollbuchse, disk-shaped membrane and a hub with root.

A Outer shell surface of the tubular bush carries around its periphery an external toothing, the under the effect of widening by an eccentric drive core in an internal toothing of a cylindrical support ring attacks. Due to a number of teeth difference between the External teeth and the internal teeth results in a low relative speed of rotation of the radially flexible Roll-off bush to the cylindrical support ring. The rotational speed of the eccentric drive core is thereby heavily stocky.

at the well-known wave gear is the ratio of the pitch circle diameter of the tooth portion to the axial length of the deformable Gear area about 1: 1. A reduction in the axial length of the deformable gearing part (external gearing) an increase in the bending angle of the deformable gearing part (external gearing). The increase in the turn angle causes the bending strain the disc-shaped membrane is increased and causes this likewise, that the engagement area between the teeth the gearing parts is reduced. This deteriorates the strength of the corrugated transmission. On top of that, the misalignment of the arrangement of the deformable gearing part the efficiency of the wave gear deteriorates considerably.

Further causes an increase in the turn angle of the deformable gearing part that the engagement area of the Teeth between the deformable gearing part (external gearing) and the internal toothing is moved.

If the turning angle of the external toothing larger is the teeth of the external teeth come radially flexible rolling bushing only at its end side area with those of the internal teeth of the support ring in engagement. A harmonic transmission of torque is characterized not possible.

Of the Invention is based on the object, a radially flexible Abrollbuchse To specify that builds compact and a harmonious torque transmission allows.

The Task is with a radially flexible rolling bush with the features of claim 1.

Thereby that the disc-shaped membrane by a plurality of Curves with different curvature is defined, where a curve with greater curvature from the root area is selected to the rifle area so that a gradual reduction in the strength of the membrane from a longitudinal axis of the radially flexible rolling bush to the rifle takes place and in particular the strength the root of the disc-shaped membrane highest is about four times the Mimimalstärke of the membrane is one created radially flexible Abrollbuchse that a correct mesh allows the external teeth in the internal teeth, even if the axial length of the tubular bush is reduced because the stiffness of the membrane is reduced and a better deformation allowed.

preferred Designs emerge from the dependent claims.

The Wall thickness of the disk-shaped membrane is preferred at the transition of the membrane to the tubular bushing least by a slight radial deflection of the tubular To enable rifle.

The Wall thickness of the box and the wall thicknesses The hub and the root of the radially flexible roller bushing are voltage-optimized so the material consumption for the production the radially flexible rolling bush is minimized. It takes into account load cases during assembly and operation of the radially flexible rolling bush. The wall thickness of the tubular bush is preferred approximately constant while the wall thickness of the flange area the disc-like membrane to the flange increases.

The Invention will now be closer with reference to an embodiment described and reproduced with reference to the accompanying drawings.

In the drawing shows:

1 a longitudinal section through an embodiment of a radially flexible rolling bush according to the invention,

2 a partial sectional view of the radially flexible Abrollbuchse on an enlarged scale as in 1 ,

In 1 is in a longitudinal section along a longitudinal axis 10 a radially flexible rolling bush 1 (flex-spline) of a wave gear 2 shown. The radially flexible rolling bush 1 is cup-shaped, formed in one piece and consists essentially of a thin-walled, tubular box 3 , which at its one axial end 11 on its outer circumferential surface an external toothing 4 wearing. At its axial end 12 that's the end 11 opposite, goes the tubular bush 3 over a transitional area 9 in a disk-shaped membrane 5 above. The membrane 5 has an inside 13 defined by a plane substantially perpendicular to the longitudinal axis 10 runs. On the other hand is an outside 14 the membrane 5 defined by a plurality of curves with a different curvature, so that the membrane 5 to a hub 6 and the root 7 having an increasing wall thickness. The hub 6 is by means of a profiled shaft connection on a shaft 8th fixed against rotation. The diaphragm area and the sleeve area are through the transition area 9 integrally connected, the transition area 9 has a constant strength. At this area of the radially flexible rolling bush 1 a minimum thickness t _{e of} the membrane is preferably provided. The wall thickness increases radially to the longitudinal axis 10 continuously to and reaches the root 7 the hub 6 a maximum value t _a , but not more than four times the wall thickness t _e at the transition region 9 corresponds (cf. 2 ).

1

radial Flexible rolling cup

2

The wave gear

3

Rifle, tube-like

4

external teeth

5

Membrane, disc-shaped

6

hub

7

root

8th

wave

9

Transition area

10

longitudinal axis

11

The End, axial

12

The End, axial

13

Inside, v. 5

14

Outside, v. 5

t _a

Strength, root

t _e

Minimum thickness, membrane

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• WO 02/36992 A1 [0002]
• - DE 69212703 T3 [0002]
• - DE 69701776 T1 [0002]

Claims (4)

Radial flexible rolling bushing ( 1 ) for a wave gear ( 2 ), consisting of a substantially in the axial direction of the radially flexible rolling bushing ( 1 ) extending tubular bush ( 3 ), which an external toothing ( 4 ) and a disk-shaped membrane ( 5 ) integral with the end of the sleeve ( 3 ) and a bottom for the radially flexible Abrollbuchse ( 1 ) and a hub ( 6 ) with a root ( 7 ) for fixing the radially flexible rolling bushing ( 1 ) on a shaft ( 8th ), characterized in that the strength (t _a ) of the root ( 7 ) of the disc-shaped membrane ( 5 ) at most about four times the minimum thickness (t _e ) of the membrane ( 5 ). Radial flexible rolling bushing according to claim 1, characterized in that the minimum thickness (t _e ) of the disk-shaped membrane ( 5 ) at the transition ( 9 ) from the disc-shaped membrane ( 5 ) to the tubular bush ( 3 ) is arranged. Radial flexible rolling bush according to claim 1 or 2, characterized in that the wall thickness of the disc-shaped membrane ( 5 ) and the wall thickness of the hub ( 6 ) voltage optimized. Radial flexible rolling bushing according to one of claims 1 to 3, characterized in that the wall thickness of the tubular bushing ( 3 ) is approximately constant and the wall thickness of the disk-shaped membrane ( 5 ) of the tubular bush ( 3 ) to the root ( 7 ) the hub ( 6 ) increases.