Frictional roller reducer

Patent metadata

Field	Value
Publication number	US-11892060-B2
Application number	US-202117926873-A
Country	US
Kind code	B2
Filing date	Dec 3, 2021
Priority date	Dec 7, 2020
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

A frictional roller reducer having a sun roller; a ring roller; a plurality of intermediate rollers having rolling surfaces coming in rolling contact with the sun roller and the ring roller; the sun roller or the ring roller having a pair of roller elements including inclined surface portions on a circumferential surface coming in rolling with rolling surfaces, the inclined surface portions inclined in directions going toward the intermediate rollers in a radial direction as going away from each other in the axial direction; a pressing device pressing the pair of roller elements in directions going closer to each other, and an elastic member arranged between the pair of roller elements, the elastic member urging the pair of roller elements in directions going away from the rolling surface of the intermediate rollers.

First claim

The invention claimed is:

1. A frictional roller reducer including:
a sun roller;
a ring roller arranged coaxially with the sun roller around the sun roller;
a plurality of intermediate rollers respectively having a rolling surface on an outer circumferential surface thereof, the rolling surfaces of the plurality of intermediate rollers coming in rolling contact with the sun roller and the ring roller;
one roller of the sun roller or the ring roller having a pair of roller elements supported so as to be able to relatively displace in an axial direction, the pair of roller elements including inclined surface portions on a circumferential surface of the one roller coming in rolling contact with the rolling surfaces, the inclined surface portions inclined in directions going toward the intermediate rollers in a radial direction as going away from each other in the axial direction;
a pressing device pressing the pair of roller elements in directions going closer to each other, and
an elastic member arranged between and directly acting on the pair of roller elements, the elastic member urging the pair of roller elements in directions going away from the rolling surface of the intermediate rollers,
wherein the pressing device has one roller element of the pair of roller elements and a cam disk supported so as to be able to relatively rotate with respect to the one roller element and to relatively displace in the axial direction, and is configured by a loading cam device which expands a distance between the one roller element and the cam disk based on a rotation of the one roller element as torque is transmitted between the sun roller and the ring roller, and presses the pair of roller elements in directions going closer to each other, and
a gap is provided between the elastic member and at least one roller element of the pair of roller elements in an initial state before the pressing device exerts pressing force.

2. The frictional roller reducer according to claim 1 , wherein
the rolling surface has a pair of intermediate roller side inclined surface portions arranged on both side portions in the axial direction, inclined in directions in which an outer diameter becomes smaller as going away from each other in the axial direction, and coming in rolling contact with the inclined surface portions, and has a connection surface portion arranged in an intermediate portion in the axial direction and having an outer diameter that does not change in the axial direction or a radius of curvature of a generating line thereof is larger than a radius of curvature of a generating line of the intermediate roller side inclined surface portions, and coming in rolling contact with the other roller of the sun roller and the ring roller.

3. The frictional roller reducer according to claim 2 , wherein
the intermediate roller side inclined surface portion has an arc-shaped or a linear generating line.

4. The frictional roller reducer according to claim 1 , wherein
the ring roller has the pair of roller elements having the inclined surface portions inclined in directions in which an inner diameter thereof becomes smaller as going away from each other in the axial direction, on an inner circumferential surface thereof.

5. The frictional roller reducer according to claim 4 , wherein
the elastic member has two-disc springs combined in a substantially V-shaped cross section so that an inner diameter side thereof opens.

6. The frictional roller reducer according to claim 4 , wherein
the elastic member has two-disc springs combined in a substantially V-shaped cross section so that an outer diameter side thereof opens.

7. The frictional roller reducer according to claim 4 , wherein
the ring roller has a connecting cylinder supporting the pair of roller elements so as to be able to relatively displace in the axial direction and not to be able to relatively rotate.

8. Frictional roller reducer according to claim 7 , wherein
the connecting cylinder has opening sections opening to an inner circumferential surface and an outer circumferential surface thereof.

9. The frictional roller reducer according to claim 8 , wherein
the opening sections respectively have a size so that end surfaces of the pair of roller elements facing each other can be visually seen from a radial outer side of the connecting cylinder.

10. The frictional roller reducer according to claim 9 , wherein
the opening sections have a size so that a contact state between the elastic member and the pair of roller elements can be visually seen from the radial outer side of the connecting cylinder.

11. The frictional roller reducer according to claim 8 , wherein
the opening sections form oil discharge holes.

12. The frictional roller reducer according to claim 8 , wherein
the opening sections are arranged at a plurality of locations uniformly spaced in a circumferential direction of the connecting cylinder.

13. The frictional roller reducer according to claim 4 including oil discharge passages communicating a radial inner side and a radial outer side of a space existing between the pair of roller elements and including the elastic member.

14. The frictional roller reducer according to claim 13 , wherein
the elastic member is configured by one or a plurality of disc springs.

15. The frictional roller reducer according to claim 14 , wherein
the elastic member has notches opening to an outer circumferential edge and/or an inner circumferential edge, or through holes penetrating an intermediate portion in the radial direction.

16. The frictional roller reducer according to claim 14 including a shim plate held between at least one roller element of the pair of roller elements and the elastic member, wherein
the shim plate has concave grooves or ridges along the radial direction on a side surface in the axial direction.

17. The frictional roller reducer according to claim 14 , wherein
a lock washer is provided between at least one roller element of the pair of roller elements and the elastic member.

18. The frictional roller reducer according to claim 14 , wherein
at least one roller element of the pair of roller elements has concave grooves along the radial direction on a tip-end surface.

19. The frictional roller reducer according to claim 13 , wherein
the elastic member is configured by a wave washer.

20. The frictional roller reducer according to claim 13 , wherein
the elastic member is configured by a torsion coil spring.

21. The frictional roller reducer according to claim 14 including a retainer having retaining holes penetrating in the axial direction at a plurality of locations in a circumferential direction and arranged between the pair of roller elements, wherein
a screw coil spring is held in each of the retaining holes.

Assignees

• Nsk Ltd

Inventors

• Kawahara Hiroshi
• Hashiguchi Hiroki
• Itagaki Hirofumi
• Hidaka Azusa
• Nishida Hiroki
• FUJITA Naofumi
• YOSHIMI Hikari
• Hitomi Naohiro
• Kita Masahiro

Classifications

• F16H13/08 Primary

  with balls or with rollers acting in a similar manner · CPC title

• F16H13/14 Primary

  for automatically varying the pressure mechanically · CPC title

• F16H57/043

  within rotary parts, e.g. axial channels or radial openings in shafts · CPC title

• F16H57/0486

  with fixed gear ratio  (axle or inter-axle differentials F16H57/0483) · CPC title

• F16H13/06

  with members having orbital motion · CPC title