EP0087547A1 — Epicyclic transmission with steplessly-variable s…

Claim 1

Independent Claim 325 words

Epicyclic transmission with steplessly-variable speed control, including: - a housing (10); - a drive shaft (28) and a driven shaft (1 0 2) extending within the housing; - a planet carrier (34) in the housing mounted on the drive shaft for rotation by the latter; - a plurality of planet wheels (46)in the form of tapered rollers which are supported for rotation by the planet carrier by means of rolling bearings (56) and-are spaced angularly from one another about the axis of rotation of the planet carrier, the planet wheels (46) having a larger frusto-conical portion (48) and asmaller frusto-conical portion (50) adjacent the larger base of the larger frusto-conical portion, and the radially external generatrices of the larger frusto-conical portions extending substantially parallel to the axis of rotation of the planet carrier; - a governing annulus (58) locked for rotation with the housing and having its internal surface in rolling contact with the surfaces of thelarger frusto-conical portions of the tapered planet wheels; - adjustment means for axial displacement of the governing annulus along the larger conical portions of the tapered planet wheels ; - a driven annulus (92) rotatable coaxially with the planet carrier and having an internal conical surface (90) complementary to the surfaces of the smaller frusto-conical portions of the tapered planet wheels, the driven annulus rotating the driven shaft, and - means for pressing together in pressure contact the surfaces of the smaller frusto-conical portions of the tapered planet wheels and the complementary conical surface of the driven annulus, and the surfaces of the larger frusto-conical portions of the tapered planet wheels and the internal surface of the governing annulus, characterised in that it further includes a freely-rotatable sun wheel in the form of a sleeve (122) which is coaxial with the planet carrier (34) and has two axially spaced bearing surfaces (136,138) in rolling contact with two complementary bearing surfaces (52,54) of each of the tapered planet wheels (46)..

Claim 2

Dependent Claim 325 words

Epicyclic transmission with steplessly-variable speed control, including: - a housing (10); - a drive shaft (28) and a driven shaft (1 0 2) extending within the housing; - a planet carrier (34) in the housing mounted on the drive shaft for rotation by the latter; - a plurality of planet wheels (46)in the form of tapered rollers which are supported for rotation by the planet carrier by means of rolling bearings (56) and-are spaced angularly from one another about the axis of rotation of the planet carrier, the planet wheels (46) having a larger frusto-conical portion (48) and asmaller frusto-conical portion (50) adjacent the larger base of the larger frusto-conical portion, and the radially external generatrices of the larger frusto-conical portions extending substantially parallel to the axis of rotation of the planet carrier; - a governing annulus (58) locked for rotation with the housing and having its internal surface in rolling contact with the surfaces of thelarger frusto-conical portions of the tapered planet wheels; - adjustment means for axial displacement of the governing annulus along the larger conical portions of the tapered planet wheels ; - a driven annulus (92) rotatable coaxially with the planet carrier and having an internal conical surface (90) complementary to the surfaces of the smaller frusto-conical portions of the tapered planet wheels, the driven annulus rotating the driven shaft, and - means for pressing together in pressure contact the surfaces of the smaller frusto-conical portions of the tapered planet wheels and the complementary conical surface of the driven annulus, and the surfaces of the larger frusto-conical portions of the tapered planet wheels and the internal surface of the governing annulus, characterised in that it further includes a freely-rotatable sun wheel in the form of a sleeve (122) which is coaxial with the planet carrier (34) and has two axially spaced bearing surfaces (136,138) in rolling contact with two complementary bearing surfaces (52,54) of each of the tapered planet wheels (46)..

Claim 3

Dependent Claim 72 words

Transmission according to Claim 1, characterised in that the contact area between the two bearing surfaces (136,138) of the sun wheel sleeve (122) and the two complementary bearing surfaces (52,54) of each tapered planet wheel (46) are arranged on common conical generatrices which converge substantially towards the point of intersection (C) of the axis of rotation of the tapered planet wheel (46) on the axis of rotation of the planet carrier (34).

Claim 4

Dependent Claim 67 words

Transmission according to Claim 1 or Claim 2, characterised in that the means for pressing together in pressure contact the smaller frusto-conical portions (50) of the tapered planet wheels (46) and the complementary conical surface (90) of the driven annulus (92), and the larger frusto-oonical portions (48) of the tapered planet wheels (46) and the internal surface of the governing annulus (58), include an oleodynamic actuator (112).

Claim 5

Dependent Claim 51 words

Transmission according to Claim 3, characterised in that the planet carrier (34) and the sun wheel sleeve (122) are axially slidably mounted on the drive shaft (28), and the oleodynamic actuator (112) operates in such a manner that it presses the sun wheel sleeve (122) axially towards the driven annulus (92).

Claim 6

Dependent Claim 66 words

Transmission according to Claim 4, characterised in that the oleodynamic actuator (112) includes an annular piston (116) which is coaxial with the drive shaft (28) and faces the smaller bases of the larger frusto-conical portions (48) of the tapered planet wheels (46), the annular piston (116) having a central hub (120) which, with the interpositioning of rolling bearings, supports the sun wheel sleeve (122) for rotation.

Claim 7

Dependent Claim 68 words

Transmission according to Claim 5, characterised in that the rolling bearings include a radial bearing (124) and an axial bearing (126) having two rings of straight rollers (128) placed between an internal centre plate (13) and first and second bearing blocks (132,134) respectively, the first of which bears against the hub (120) of the piston (116) and the second of which bears against the sun wheel sleeve (122).

Claim 8

Dependent Claim 97 words

Transmission according to Claim 5, characterised in that: - the tapered planet wheels (46) are freely radially displaceable relative to the planet carrier (34); - the governing annulus (58) is supported by the housing (10) so as to be self-centring relative to the tapered planet wheels (46), and - the contact areas between the tapered planet wheels (46) and the governing annulus (58) and the driven annulus (92), respectively, and the bearing areas between the sun wheel sleeve (122) and the rolling bearings between the sun wheel sleeve (122) and the piston (116), have slightly convex surfaces.

Claim 9

Dependent Claim 65 words

Transmission according to Claim 7, characterised in that each of the tapered planet wheels (46) has an axial cavity through which is inserted a pin (44) on which the planet wheel (46) is freely rotatable by means of a pair of radial rolling bearings (56), and the ends of which are slidable radially to engage in corresponding notches (38a, 40a) of the planet carrier (34).

Claim 10

Dependent Claim 70 words

Transmission according to Claim 7, characterised in that it -includes an internal tubular body (66) which is fixed to the housing (10) by a pair of coaxial radial pins (68) and has a pair of diametrally-opposed axial slots (64) staggered at 90° relative to the pins (68) , in which are guided two rollers (62) carried by a pair of corresponding radial pins (60) integral with the governing annulus (58).

Claim 11

Dependent Claim 38 words

Transmission according to Claim 1, characterised in that the adjustment means for axial displacement of the governing annulus (58) along the larger conical portions (48) of the tapered planet wheels (46) include a plurality of oleodynamic actuators (70).

Claim 12

Dependent Claim 31 words

Transmission according to Claims 7 and 10, characterised in that the oleodynamic actuators (70) are provided with rods (76) having with convex end surfaces in contact with the governing annulus (58).

Claim 13

Dependent Claim 81 words

Transmission according to the preceding claims, characterised in that it further includes lubrication means for continuously supplying a liquid lubricant under pressure to the contact areas between the tapered planet wheels (46) and the governing annulus (58), the driven annulus (92) and the sun wheel sleeve (122),respectively, and to the rolling bearings (56,124,126) between the tapered planet wheels (46) and the planet carrier (34), and between the sun wheel sleeve (122) and the piston (116) of the oleodynamic actuator (112), respectively.

Claim 14

Dependent Claim 45 words

Transmission according to Claim 12, characterised in that the lubrication means include an inlet union (140), a perforated annular pipeline (144) fitted coaxially with the governing annulus (58), and a telescopic pipe (142) which connects the inlet union (140) with the perforated annular pipeline (144).

Claim 15

Dependent Claim 23 words

Transmission according to Claim 12, characterised in that it further includes supply means for operating the oleodynamic actuators (70,112) with the lubricant liquid.

Epicyclic transmission with steplessly-variable speed control, having tapered planet wheels of dual conicity

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