Electrotor-Simplex ~ Power Train - Crown & Pinion

Overview:

Power train with crown and pinion for final reduction. Primary reduction can be spur gear set or sheave and belt.

Notes:

2,500 surface feet per minute is the maximum recommended pitch line velocity for spiral bevel gears.

Concern:

There does not appear to be a reasonable way to locate an overrunning clutch between the crown and the rotorhub.

FORM: Arrow Spiral Stock Gear Selection

For reference only to get an idea of the values for quality spiral bevel gears. Ratio 3:1. Spiral tooth bevel gears.

This is for slower motor (5,500 RPM, not 6,000 RPM) and lower horsepower rating on the engine, plus faster RRPM.

This is for 4:1 primary reduction and 3:1 Arrow secondary reduction. The motor speed is 5,500 RPM with the slower speed rotor. Note that the stock Arrow gear can only be supplied with a single handing of spiral.

This is hover. See note 2 below.

See Hamilton table below for actual.

 

Arrow Pinion Part No.

 10P45L15

 10P45L15

 10P45L15

 10P45L15

Item 0226

Item 0226

Item 0226

Item 0226

 

Arrow Gear Part No.

 10P15R45

 10P15R45

 10P15R45

 10P15R45

Item 0227

Item 0227

Item 0227

Item 0227

 

Horsepower;

20

15

15

11 (2)

 

Pinion Speed:

2000

1833

1375

1833

 

Pinion Working Torque:

630

516

688

378

 

Estimated Rated Pinion Torque:

1260

1032

1375

756

 

Catalog Rated Pinion Torque:

540

540

540

540

 

Catalog Pinion Pitch Diameter:

1.5

1.5

1.5

1.5

 

Pitch Line Velocity:

786

720

540

720

 

Dynamic Factor:

0.8577

0.8626

0.8777

0.8626

 

Allowable Pinion Torque:

463

463

474

466

 

Service Factor: (1)

0.7349

0.9031

0.6894

1.2315
  1. Perhaps the service factor might be greater since the power source is a motor, not a reciprocating engine.
  2. 11 hp is the power required to hover with a 611 RRPM and 8 ft rotor radius.

FORM: Hamilton Bevel Gear Selection.

 

Gear:

Rush Gear

Straight tooth

Rush Gear

Straight tooth

Rush Gear

Straight tooth

 

Teeth: (4)

18 & 72

15 & 60

15 & 60

 

 

Item 0234& 0235

xx

xx

 

Pinion Speed (1) [rpm]

2000

2000

2444

 

Catalog Pinion Pitch Dia. [in]

1.5

1.5

1.5

 

Pitch Line Velocity [fpm]

786

786

960

 

Diametral Pitch

12

10

10

 

Face Width [in]

0.61

0.72

0.72

 

Allowable Contact Stress

190,000

190,000

190,000

 

Allowable Bending Stress

13,500

13,500

13,500

 

Elastic Coefficient

Pinion & Gear - Steel

Pinion & Gear - Steel

Pinion & Gear - Steel

 

Load Distribution Factor (3)

Neither straddle mounted

Neither straddle mounted

Neither straddle mounted

 

Geometry Factor [I]

.148

.143

.143

 

Geometry Factor [J]

.314

.292

.292

 

Durability [hp] (2) (5) SF=1

11.2

12.8

15.6

 

Strength [hp] (2) (5) SF=1

7.2

9.1

11.1

 

Output Speed: [rpm]

500

500

611

See FORM for additional data.
    1. This is based on a motor speed of 6,000 RPM and a 3:1 primary reduction. Or, 5,500 RPM and 2.25 primary reduction.
    2. Increasing the tooth hardness will increase the horsepower rating
    3. If the pinion is straddle mounted then the values will be 12% higher
    4. If spiral tooth 4:1 gears are available the horsepower rating will be higher.
    5. Perhaps the service factor might be greater since the power source is a motor, not a reciprocating engine.

 Working Papers:

 

DESIGN:

 

MAKE:

 

BUY:

 

Items:

DESIGN:

 

Name

Item

 

 

 

 

 

 

MAKE:

 

Name

Item

 

 

 

 

 

 

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Last Revised: September 27, 2009