US-20260126099-A1 - MECHANICAL SPEED REDUCING ASSEMBLY

Abstract

Mechanical speed reducing assembly comprising a first sun wheel, a first ring wheel arranged concentrically about the first sun wheel, such that the first sun wheel and the first ring wheel share a first symmetry axis, a hollow first planetary member comprising a first cylindrical section in frictional engagement with an outer surface of the first sun wheel and with an inner surface of the first ring wheel, the first planetary member being arranged to rotate about a second axis, wherein the first planetary member comprises a circumferential first groove and a circumferential second groove, which are spaced apart from each other by the first cylindrical section, and a first alignment ring which is secured to the first sun wheel or to the first ring wheel against motion along the first symmetry axis and which protrudes into the first groove or the second groove.

Inventors

• Jack SCHORSCH
• Alfons SCHURE
• Job NEVEN

Assignees

• INNOVATIVE MECHATRONIC SYSTEMS B.V.

Dates

Publication Date

20260507

Application Date

20230928

Priority Date

20220928

Claims (20)

1. 1 . Mechanical A mechanical speed reducing assembly comprising: a first sun wheel, a first ring wheel arranged concentrically about the first sun wheel, such that the first sun wheel and the first ring wheel share a first symmetry axis, a hollow first planetary member comprising a first cylindrical section, which first cylindrical section is in frictional engagement with an outer surface of the first sun wheel and with an inner surface of the first ring wheel, the first planetary member being arranged to rotate about a second axis, wherein the first planetary member comprises a circumferential first groove and a circumferential second groove, which are spaced apart from each other by the first cylindrical section, and a first alignment ring which is secured to the first sun wheel or to the first ring wheel against motion along the first symmetry axis and which protrudes into the first groove or the second groove.
2. 2 . The assembly according to claim 1 , wherein the first alignment ring comprises an alignment shoulder, which is arranged to engage with a groove side face of the first groove or of the second groove, which groove side face is generally perpendicular to the second axis.
3. 3 . The assembly according to claim 2 , wherein the first groove or the second groove comprises a mating shoulder arranged to engage with the alignment shoulder.
4. 4 . The assembly according to claim 1 , wherein the first ring wheel comprises a first recess extending circumferentially about the first symmetry axis, which first recess is arranged to accept the first alignment ring partially.
5. 5 . The assembly according to claim 4 , wherein the first ring wheel comprises a second recess extending circumferentially about the first symmetry axis and spaced apart from the first recess along the first symmetry axis, which second recess is arranged to accept the first alignment ring partially.
6. 6 . The assembly according to claim 1 , wherein the first sun wheel comprises a first recess extending circumferentially about the first symmetry axis, which first recess is arranged to accept the first alignment ring partially.
7. 7 . The assembly according to claim 6 , wherein the first sun wheel comprises a second recess extending circumferentially about the first symmetry axis and spaced apart from the first recess along the first symmetry axis, which second recess is arranged to accept the first alignment ring partially.
8. 8 . The assembly according to claim 7 , further comprising a second alignment ring similar to the first alignment ring, which second alignment ring is to be arranged partially in the second recess.
9. 9 . The assembly according to claim 8 , wherein the first alignment ring engages with the first groove or the second alignment ring engages with the second groove.
10. 10 . The assembly according to claim 1 , wherein the first alignment ring, the second alignment ring, the first recess or the second recess comprises a curved crown.
11. 11 . The assembly according to claim 1 , further comprising a second planetary member and a third planetary member similar to the first planetary member, which planetary members are arranged about the first symmetry axis, each of which is in frictional engagement with the outer surface of the first sun wheel and with the inner surface of the first ring wheel.
12. 12 . The assembly according to claim 1 , wherein at least the first planetary member comprises a second cylindrical section similar to the first cylindrical section, wherein the first groove is arranged between the second cylindrical section and the first cylindrical section.
13. 13 . The assembly according to claim 11 , further comprising a second sun wheel and a second ring wheel arranged concentrically about the second sun wheel, wherein the second sun wheel and the second ring wheel share the first symmetry axis, wherein the second cylindrical section is in frictional engagement with an outer surface of the second sun wheel and with an inner surface of the second ring wheel.
14. 14 . The assembly according to claim 13 , further comprising a bearing arranged about the first axis of symmetry, wherein the bearing engages with a sun wheel side face of the first sun wheel and a sun wheel side face of the second sun wheel, which sun wheel side faces are perpendicular to the first symmetry axis.
15. 15 . The assembly according to claim 13 , further comprising a third ring wheel, wherein the first ring wheel is arranged between the second ring wheel and the third ring wheel, wherein at least the first planetary member, particular a third cylindrical section, is in frictional engagement with an inner surface of the third ring wheel.
16. 16 . The assembly according to claim 15 , wherein the second and third ring wheel are coupled rotationally.
17. 17 . A method of manufacturing a mechanical speed reducing assembly including a first sun wheel, a first ring wheel having a first recess and a second recess, a hollow first planetary member comprising a first cylindrical section in frictional engagement with an outer surface of the first sun wheel and with an inner surface of the first ring wheel, the first planetary member being arranged to rotate about a second axis, wherein the first planetary member comprises a circumferential first groove and a circumferential second groove the method, comprising inserting a first alignment ring into the first recess of the first ring wheel; inserting the first alignment ring into the first groove of the first planetary member; and arranging the first sun wheel relative to the first ring wheel such that these are arranged concentrically and share a first symmetry axis.
18. 18 . The method of claim 17 , further comprising inserting a second alignment ring into the second groove of the first planetary member.
19. 19 . The method of claim 18 , further comprising inserting the second alignment ring into the second recess of the first ring wheel.
20. 20 . The method of claim 19 , further comprising forming a curved crown using the first alignment ring, the second alignment ring, the first recess, and the second recess.

Description

The present invention relates to a mechanical speed reducing assembly comprising several rotationally symmetric members and to a method of assembling the mechanical speed reducing assembly. Depending on which of the member(s) receives an input torque, the suggested mechanical speed reducing assembly is suitable for altering the magnitude or direction of the output rotational speed, with respect to the input rotational speed. WO 2018/178380 A1 discloses a compound planetary friction drive comprising a first sun wheel and planetary wheels, wherein said first sun wheel engages said planetary wheels, which planetary wheels are arranged with two outer parts having a first radius and a central part having a second radius, wherein the second radius differs from the first radius and transition regions are provided between the outer parts and the central part, and wherein an outer ring annulus and a central ring annulus are provided that are in driving engagement with the planetary wheels, wherein the outer ring annulus has two parts between which, along the length of the planetary wheels, the central ring annulus is disposed, wherein the first sun wheel is in frictional engagement with the outer parts of the planetary wheels, said outer parts of the planetary wheels are in frictional engagement with the parts of the outer ring annulus and the central ring annulus is in frictional engagement with the central part of the planetary wheels, wherein the planetary wheels are both hollow and compressible uninterruptedly along their entire length spanning the outer parts, the transition regions and the central part. Problem and Solution A problem to be solved can be seen in providing an improved mechanical speed reducing assembly. This problem is solved by the mechanical speed reducing assembly according to claim 1 and by the preferred embodiments also according to the dependent claims. The mechanical speed reducing assembly according to the invention (first aspect) comprises a first sun wheel and a first ring wheel. The first ring wheel is arranged concentrically about the first sun wheel, such that the first sun wheel and the first ring wheel share a first symmetry axis. The assembly further comprises at least one hollow first planetary member having a first cylindrical section in frictional engagement with an outer surface of the first sun wheel and with an inner surface of the first ring wheel. The first cylindrical section serves as a running surface of the first planetary member. The first planetary member is arranged to rotate about a second axis and comprises a circumferential first groove and a circumferential second groove, which are spaced apart from each other by the first cylindrical section. The assembly further comprises at least a first alignment ring which is secured to the first sun wheel or to the first ring wheel against moving along the first symmetry axis and which protrudes into the first groove or the second groove. The alignment ring which is secured against moving along the first symmetry axis may act against undesired motion of the first planetary member along the first or second axis, as the alignment ring also protrudes into the first groove or the second groove. This may help to reduce slipping and/or abrasion particularly caused by relative rotation of the first planetary member while the assembly is operational. In the prior art, planetary members are often constrained by means of an axle & cam system to achieve alignment of the planetary members with the sun wheel and ring wheel. In the prior art, an alignment feature may serve to align an output member of the assembly with the rotational axis of the planetary members. The first planetary member of the present invention may move and rotate with respect to more than one axis. The second axis of the planetary member is not fixed with respect to the first symmetry axis. An output member of the assembly can be fixed by an external bearing. The alignment ring may urge the second axis to align more with the first symmetry axis. The first alignment ring may provide a thrust bearing surface for imposing thrust on the first planetary member to urge the second axis to align more with the first symmetry axis. Further, for any given amount of compression force applied to a contact surface, a fixed amount of traction ‘thrust’ is available, as determined by the coefficient of friction. If any degree of skewness occurs, the ‘angle’ along which that traction thrust is vectored and becomes non-parallel with the desired line of motion. Any component of the vector which is not parallel with the allowed line of action becomes lost. If the assembly is constrained against axial motion, the components must slip in the axial direction. The coefficient of friction when in slip is lower than when in traction, causing additional losses. An angle of skew may occur which causes the assembly to lose tractive effort rapidly. Changing the profile & location of the first a