Planetary Gears
This component represents a Planetary gear set using a conceptual model.
Learn about Planetary gears:
Creating or Modifying Planetary Gears
To create or modify Planetary gears:
1. From the Driveline Components menu, point to Planetary Gear, and then select New/Modify.
3. Select OK.
About Planetary Gears
The Planetary gear is a conceptual planetary gear set. The planets are not directly modeled. User define the gear set by specifying the sun, ring, carrier, the revolute joints that attach those parts, and a property file. The property file specifies the number of teeth on the sun gear and the ring gear.
User define a Planetary gear set by first building the following parts:
■Sun part
■Ring part
■Carrier part
User must attach these parts to the powerplant, and specify these joints when building the Planetary gear:
■Sun joint
■Ring joint
■Carrier joint
A construction frame determines the Planetary gear axis.
The Planetary gear connects the sun part to the sun_lash part (and the ring part to a ring_lash part). The sun_lash part is connected to the sun part through a revolute joint and a torque to model the gear lash and stiffness properties (defined using a property file). The same model technique is used for the ring. The torque expression uses the backlash formulation, as explained for rotational backlash.
The Planetary gear ratio is set between sun lash part, ring part, and carrier part through a coupler, enforcing the following constraint:
(r1 * q1) + (r2 * q2) + (r3 * q3) = 0
where r1, r2, and r3 are the scale factors for the three joints, and for each joint, q1, q2, and q3 are rotational displacements of the joint I marker with respect to the joint J marker.
Therefore, using the Willis formula, we can determine that the coupler factors are:
r1: sun number of teeth applied to the sun joint
r2: (sun number of teeth + ring number of teeth) applied to the carrier joint
r3: ring number of teeth applied to the ring joint
r2: (sun number of teeth + ring number of teeth) applied to the carrier joint
r3: ring number of teeth applied to the ring joint
In the Standard Interface user can vary the property file. The property file specifies the sun and ring number of teeth. It also contains the mass and inertia values for the gear parts.
Request Definition
Component name: | Component units: | Definition: |
|---|---|---|
sun_RPM | angular velocity | Angular velocity of the sun with respect to the powerplant. |
ring_RPM | angular velocity | Angular velocity of the ring with respect to the powerplant. |
carrier_RPM | angular velocity | Angular velocity of the carrier with respect to the powerplant. |
sun_backlash | angle | Angular lash between the sun and sun lash parts. |
ring_backlash | angle | Angular lash between the ring and ring lash parts. |
sun_backlash_torque | torque | Torque acting between the sun and sun lash parts. |
ring_backlash_torque | torque | Torque acting between the ring and ring lash parts. |
Subsystem Parameters
Property file (<db_name>/gear_elements.tbl)
Example Planetary Gear Property File
$----------------------------------------------------------MDI_HEADER
[MDI_HEADER]
FILE_TYPE = 'pgf'
FILE_VERSION = 1.0
FILE_FORMAT = 'ASCII'
HEADER_SIZE = 6
$---------------------------------------------------------------UNITS
[UNITS]
LENGTH = 'mm'
ANGLE = 'degrees'
FORCE = 'newton'
MASS = 'kg'
TIME = 'second'
$------------------------------------------------PLANETARY_GEAR_MODEL
[PLANETARY_GEAR_MODEL]
PLANETARY_GEAR_MODEL = 'conceptual'
PLANETARY_GEAR_TYPE = 'internal' $allowed options are: 'internal' , 'external'
LASH_MODEL = 'backlash' $allowed options are: 'backlash' , 'bistop'
$-----------------------------------------------------------------SUN
[SUN]
NUMBER_OF_TEETH = 31
BACKLASH = 1
STIFFNESS = 1E+06
DAMPING = 1E+02
$ the following parameter is used if lash_model = 'backlash'
SHARPNESS = 100
$ the following 3 parameters are used if lash_model = 'bistop'
LASH_STIFFNESS_DIVISOR = 10
FORCE_DEFORMATION_EXPONENT = 1.3
FULL_DAMPING_PENETRATION = 1E-02
$ sun gear mass & inertia properties
SUN_LASH_MASS = 1.0
SUN_LASH_IXX = 1000.0
SUN_LASH_IYY = 1000.0
SUN_LASH_IZZ = 1000.0
$----------------------------------------------------------------RING
[RING]
NUMBER_OF_TEETH = 77
BACKLASH = 1
STIFFNESS = 1E+06
DAMPING = 1E+02
$ the following parameter is used if lash_model = 'backlash'
SHARPNESS = 100
$ the following 3 parameters are used if lash_model = 'bistop'
LASH_STIFFNESS_DIVISOR = 10
FORCE_DEFORMATION_EXPONENT = 1.3
FULL_DAMPING_PENETRATION = 1E-02
$ ring gear mass & inertia properties
RING_LASH_MASS = 1.0
RING_LASH_IXX = 1000.0
RING_LASH_IYY = 1000.0
RING_LASH_IZZ = 1000.0
$--------------------------------------------------------------PINION
[PINION]
NUMBER_OF_TEETH = 23
$ pinion gear mass & inertia properties
PINION_MASS = 1.0
PINION_IXX = 1000.0
PINION_IYY = 1000.0
PINION_IZZ = 1000.0