Ball screw drive
A ball screw drive ( 10 ) including a threaded spindle ( 12 ) having a first, free end ( 16 ) and a second end ( 17 ) which can be connected to a drive, and a spindle nut ( 14 ) at least partially enclosing the threaded spindle ( 12 ) coaxially. A plurality of balls ( 26 ) recirculate in the space between the threaded spindle ( 12 ) and the spindle nut ( 14 ) form the core element. An extension sleeve ( 15 ), which connects coaxially to the spindle nut ( 14 ), is fixedly connected to the latter and moves together with it relative to the threaded spindle ( 12 ). At the first end ( 16 ) of the threaded spindle ( 12 ), a substantially circular bearing ring ( 18, 30, 50, 70 ) is attached to the outer circumference of the threaded spindle ( 12 ), which circular bearing ring serves as a shaft bearing between the threaded spindle ( 12 ) and the extension sleeve ( 15 ) and which has a noise-dampening effect due to at least one integrated spring/damping element. This spring/damping element of the bearing ring ( 30, 50, 70 ) is preferably a combination of at least one notch ( 32, 52, 72 ) on the inner circumference of the bearing ring ( 30, 50, 70 ) and an annular gap ( 34, 54, 74 ).
1. A ball screw drive ( 10 ), comprising:
a threaded spindle ( 12 ) that defines an axis and having a first, free end ( 16 ) and a second end ( 17 ) which is connectable to a drive;
a spindle nut ( 14 ) that at least partially surrounds the threaded spindle ( 12 ) coaxially;
a plurality of balls ( 26 ) recirculating in a space between the threaded spindle ( 12 ) and the spindle nut ( 14 );
an extension sleeve ( 15 ) that coaxially connects to the spindle nut ( 14 ), and is fixedly connected thereto and movable together therewith relative to the threaded spindle ( 12 );
a bearing ring ( 18 , 30 , 50 , 70 , 90 ) attached at the first end ( 16 ) on an outer circumference of the threaded spindle ( 12 ), said bearing ring serves as a shaft bearing between the threaded spindle ( 12 ) and the extension sleeve ( 15 ); and
the bearing ring ( 18 , 30 , 50 , 70 , 90 ) has an integrated spring/damping element formed by a combination of at least one axially extending notch ( 32 , 52 , 72 , 92 ) that extends parallel to the axis across an inner circumference of the bearing ring ( 30 , 50 , 70 , 90 ) and a gap ( 34 , 54 , 74 , 94 ) that extends radially entirely through the bearing ring to provide sound-dampening.
2. The ball screw drive ( 10 ) according to claim 1 , wherein the integrated spring/damping element of the bearing ring ( 30 , 50 , 70 ) additionally comprises at least one indentation ( 36 , 56 , 76 ) on the outer circumference.
3. The ball screw drive ( 10 ) according to claim 2 , wherein the indentation ( 36 , 56 , 76 ) on the outer circumference is formed as a radially inwardly extending slot having a depth that, measured from the outer circumference, is 30-60% of a maximum radial width of the bearing ring ( 30 , 50 , 70 ).
4. The ball screw drive ( 10 ) according to claim 2 , wherein the indentation or slot ( 36 , 56 , 76 ) has a width profile that is constant over a majority of an axial length thereof.
5. The ball screw drive ( 10 ) according to claim 2 , wherein the at least one indentation ( 56 , 76 ) includes at a radially inner end that connects to a further slot ( 59 , 79 ), and said further slot when viewed from a center ( 60 , 80 ) of the bearing ring ( 50 , 70 ), follows a course defined by a circular arc or a chord and extends for an angle of 20° to 60°.
6. The ball screw drive ( 10 ) according to claim 5 , wherein at an end of the further slot ( 59 , 79 ) facing away from the indentation ( 56 , 76 ), the further slot includes a substantially circular opening.
7. The ball screw drive ( 10 ) according to claim 5 , wherein the further slot ( 59 , 79 ) has a non-constant width along the course thereof.
8. The ball screw drive ( 10 ) according to claim 5 , wherein a piece of material defined by the indentation ( 56 , 76 ), the further slot ( 59 , 79 ) and the outer circumference of the bearing ring ( 50 , 70 ) forms a pressing element ( 58 , 78 ) with a resilient tongue ( 57 , 77 ).
9. The ball screw drive ( 10 ) according to claim 8 , wherein the pressing element ( 58 , 78 ) has a radius deviating positively from a nominal outer diameter.
10. The ball screw drive ( 10 ) according to claim 1 , wherein the bearing ring ( 18 , 30 , 50 , 70 ) is formed in one piece from a thermoplastic material.
11. The ball screw drive ( 10 ) according to claim 1 , wherein the integrated spring/damping element of the bearing ring ( 90 ) further comprises at least one pressing element ( 98 ) on the outer circumference.
12. The ball screw drive ( 10 ) according to claim 11 , wherein the at least one pressing element ( 98 ) of the bearing ring ( 90 ) is made of a material having greater elasticity than a material of a remaining part of the bearing ring ( 90 ).
13. The ball screw drive ( 10 ) according to claim 12 , wherein the pressing element ( 98 ) has a radius deviating positively from a nominal outer diameter.