Multi-range starter-generator drive

• US 4,708,030 A
• Filed: 03/18/1985
• Issued: 11/24/1987
• Est. Priority Date: 03/18/1985
• Status: Expired due to Fees

• Current Assignee: Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Cordner, Michael A.
• Primary Examiner(s): Bonck, Rodney H.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/713,879
• Time in Patent Office: 981 Days
• Field of Search: 74/781 R, 74/782, 74/783, 74/793, 74/794, 74/674, 74/740, 74/750 R, 74/686, 192/586, 192/85 AA, 192/103 F, 123/179 A, 123/179 AS, 123/179 B, 290/1 C, 318/11, 318/12, 318/13
• US Class Current: 475/296
• CPC Class Codes: F02C 7/268 Starting drives for the rotor , acting directly on the rotor of the gas turbine to be started
• CPC Class Codes: F02C 7/32 Arrangement, mounting, or driving, of auxiliaries
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F16D 35/005 with multiple lamellae

Abstract

A starter-generator drive usable in an aircraft must be of the smallest possible size and the lowest possible weight and have maximum reliability. A drive having a multi-speed transmission and a controllable hydro-viscous dissipative clutch can be interposed between an engine and a starter-generator to achieve maximum efficiency in the drive and meets the foregoing objectives.

The starter-generator drive has a multi-speed transmission for stepping the input speed from an engine to a hydro-viscous dissipative clutch to provide plural speed ranges of operation and thus limit the amount of slip that occurs within the clutch in each range to provide the constant speed drive of the generator. The dissipative clutch operates in a hydro-viscous manner whereby sudden changes of speed, as the multi-speed transmission shifts, do not vary the torque transmitted to the generator and therefore the speed of the generator. This avoids transients in the output power frequency of the generator during ratio changing of the multi-speed transmission. The starter-generator drive also provides for dissipative engine start utilizing the generator as an electric motor.

Claims

1. A multi-range starter-generator drive connected between a variable speed engine and a generator, comprising:

a first shaft drivingly coupled to the variable speed engine, a second shaft drivingly coupled to the generator to be driven at constant speed, a controllable hydro-viscous dissipative clutch having a movable control member said hydro-viscous clutch being operatively connected to said shafts controllable for constant speed drive of the second shaft and the generator with the engine operating at variable speeds, and plural drive output means interposed between said first shaft and said clutch providing different drive ratios between said engine and said clutch to achieve a more nearly constant speed input to said clutch over the entire range of engine spees.

2. A multi-range aircraft starter-generator drive as defined in claim 1 wherein said means providing different drive ratios comprises planetary gear means with plural drive outputs.

3. A multi-range aircraft starter-generator drive as defined in claim 2 wherein said planetary gear means includes a planetary element connected to an selectively operable brake.

4. A multi-range aircraft starter-generator drive as defined in claim 2 wherein each of said plural drive outputs has a selectively operable clutch associated therewith.

5. A multi-range starter-generator drive comprising:

a first shaft connectable to a variable speed engine, a second shaft drivingly coupled to a generator to be driven at constant speed, controllable hydro-viscous dissipative clutch means operatively connected to said shafts for constant speed drive of the second shaft and the generator with the engine operating at variable speeds, and multi-speed transmission means interposed between said first shaft and said dissipative clutch means providing plural output drive ratios from said engine to said dissipative clutch means to achieve a more nearly constant speed input to said dissipative clutch means over the entire range of engine speeds, said multi-speed transmission means having plural drive outputs and each drive output having a selectively operable clutch associated therewith.

6. A multi-range aircraft starter-generator drive in combination with a variable speed engine and a generator for alterntively driving the generator from the variable speed engine or utilizing the generator as a motor to start the engine, comprising:

a first shaft drivingly coupled to the engine, planetary gear means having plural relatively movable planetary elements with a first planetary element connected to said first shaft, a selectively operable brake and at least one drive train connected to planetary elements of the planetary gear means, a hydro-visous dissipative clutch having a member movable to control the slip of the clutch and a pair of drive elements with one of said pair of drive elements drivingly coupled to the generator and the other to said drive train and said drive train having a selectively operable clutch whereby there can be different drive ratios between the engine and the dissipative clutch depending upon selective operation of the clutch and the brake.

7. A constant speed drive for driving a generator at constant speed from a variable speed engine comprising, a first shaft for operative connection to an engine, planetary gear means having plural relatively movable planetary elements with a first planetary element connected to said first shaft, and also having second, third and fourth planetary elements, a selectively operable brake connected to said second planetary element, first and second drive trains with the first drive train connected to the third planetary element for movement therewith and the second drive train connected to the fourth planetary element, hydroviscous means for transmitting torque and having a pair of shafts with one of said pair of shafts drivingly coupled to the generator, said first and second drive trains being both connected to the other of said pair of shafts, and each of said first and second drive trains having a selectively operable clutch whereby there can be different drive ratios between the engine and the constant torque-transmitting means depending upon which of said selectively operable clutches is operable as well as selective operation of the brake.

8. A multi-range aircraft starter-generator drive for alternatively driving the generator from a variable speed engine or utilizing the generator as a motor to start the engine, comprising:

a first shaft for operative connection to an engine, planetary gear means having plural relatively movable planetary elements with a first planetary element connected to said first shaft, and also having second, third and fourth planetary elements, a selectively operable brake connected to said second planetary element, first and second drive trains with the first drive train connected to the third planetary element for movement therewith and the second drive train connected to the fourth planetary element, a hydro-viscous dissipative clutch having a pair of clutch shafts with one of said pair of clutch shafts drivingly coupled to the generator, said first and second drive trains being both connected to the other of said clutch shafts, and each of said first and second drive trains having a selectively operable clutch whereby there can be any one of three different drive ratios between the engine and the dissipative clutch depending upon which of said selectively operable clutches is operable as well as selective operation of the brake.