REDUCTION GEAR WITH EPICYCLIC GEAR TRAIN HAVING ROLLER-BEARING-MOUNTED PLANET SPINDLES

• US 20130324343A1
• Filed: 05/29/2013
• Published: 12/05/2013
• Est. Priority Date: 05/30/2012
• Status: Active Grant

• Current Assignee: Safran Aircraft Engine Company
• Original Assignee: Snecma (Safran SA)
• Inventors: GALLET, Francois
• Granted Patent: US 8,986,146 B2
• Time in Patent Office: Days
• US Class Current: 475/159
• CPC Class Codes: F02C 3/107 with two or more rotors connected by power transmission
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: F02K 3/06 with front fan
• CPC Class Codes: F05D 2260/4031 as in toothed gearing
• CPC Class Codes: F16H 2057/085 Bearings for orbital gears
• CPC Class Codes: F16H 3/44 using gears having orbital motion the gear-ratio being changed by inversion of torque direction F16H3/005
• CPC Class Codes: F16H 57/082 Planet carriers
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A reduction gear with epicyclic gear train comprising an annulus gear (14), at least one planet gear (12) rolling on said annulus gear and able to rotate about a planet spindle (16) borne by a planet carrier (13), wherein said planet spindle is mounted such that it can itself rotate about its axis relative to said planet carrier. The invention is suited to a reduction gear mounted in a high bypass ratio jet engine for driving the fan thereof.

Claims

1. A reduction gear with epicyclic gear train comprising an annulus gear, at least one planet gear rolling on said annulus gear and able to rotate about a planet spindle borne by a planet carrier, said planet spindle being mounted such that it can itself rotate about its axis relative to said planet carrier,

wherein there are two modes of operation:

a first mode in which said planet spindle is rigidly attached to the planet carrier and a second mode in which said planet spindle can rotate freely relative to the planet carrier.

2. The reduction gear as claimed in claim 1, in which the planet gear rotates about its planet spindle by means of a journal bearing and the planet spindle is mounted on the planet carrier via the intermediary of a rolling bearing.

3. The reduction gear as claimed in claim 1, in which switching from one mode to the other is performed as a function of the temperature of the lubrication oil of said reduction gear.

4. The reduction gear as claimed in claim 3, in which switching from one mode to the other is actuated by an actuation means positioned so as to be in contact with said lubrication oil and comprising a shape memory material.

5. The reduction gear as claimed in claim 4, in which said actuation means is a flange plate in the shape of a circular annulus, the central bore of which is attached to said spindle and the outer end of which moves in the axial direction as a function of the temperature of the lubrication oil.

6. The reduction gear as claimed in claim 5, in which said flange plate comprises, at its outer end, at least one first face which extends in the radial direction facing a corresponding face positioned on said planet carrier, the axial positioning of said end, produced by the oil at the nominal operating temperature of the reduction gear, being designed so as to cause said two faces to press against each other.

7. The reduction gear as claimed in claim 5, in which said flange plate comprises at its outer end at least one second face which extends in the radial direction facing a corresponding face positioned on said planet gear, the axial positioning of said end, produced by the oil at a temperature below the nominal operating temperature of the reduction gear, being designed so as to cause said two faces to press against each other.

8. The reduction gear as claimed in claim 6, in which the pressure exerted by said flange plate against the wall of the planet carrier is such that, in the event of an overtorque as the result of the journal bearings seizing, the planet spindle can still rotate in order to prevent the reduction gear from locking up.

9. A fan module of a dual-flow jet engine comprising a fan shaft driven by a reduction gear as claimed in claim 1.

10. A dual-flow jet engine comprising a fan module as claimed in claim 9.