Method of shifting a tandem drive axle having an inter-axle differential
First Claim
1. A method of shifting a power distribution unit for a vehicle from a first operating state to a second operating state, the method comprising the steps of:
- drivingly engaging a first axle assembly with a first output of the power distribution unit;
drivingly engaging a second axle assembly with a second output of the power distribution unit;
drivingly engaging an input of the power distribution unit with an output of a power source, the power distribution unit including an inter-axle differential, the first output, the second output, and a first clutching device having a first position and a second position, the first clutching device in the first position locking the inter-axle differential, engaging the first output with the input of the power distribution unit, and disengaging the second output from the inter-axle differential, the first clutching device in the second position unlocking the inter-axle differential and engaging the first output and the second output with the inter-axle differential;
placing the first clutching device in one of the first position and the second position;
applying a rotational force to the input of the power distribution unit;
adjusting the rotational force transferred to the power distribution unit to facilitate moving the first clutching device;
moving the first clutching device from one of the first position and the second position to a third position, the first clutching device in the third position neither locking the inter-axle differential nor engaging the second output with the inter-axle differential;
adjusting a rotational speed of the input of the power distribution unit to facilitate moving the first clutching device from the third position;
moving the first clutching device from the third position to one of the first and second positions; and
adjusting the rotational force transferred to the power distribution unit.
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Accused Products
Abstract
A method of shifting a power distribution unit for a vehicle from a first operating state to a second operating state is provided. The method includes the step of adjusting a rotational speed of a portion of a second axle assembly using a clutching device to impart energy to a lubricant within the second axle assembly. A controller in communication with a power source of the vehicle adjusts an operating condition of the power source to facilitate moving the clutching device. The power distribution unit includes an inter-axle differential capable being placed in a locked condition by the clutching device and of accommodating a rotational difference between a first output gear and a second output gear with the inter-axle differential.
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Citations
44 Claims
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1. A method of shifting a power distribution unit for a vehicle from a first operating state to a second operating state, the method comprising the steps of:
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drivingly engaging a first axle assembly with a first output of the power distribution unit; drivingly engaging a second axle assembly with a second output of the power distribution unit; drivingly engaging an input of the power distribution unit with an output of a power source, the power distribution unit including an inter-axle differential, the first output, the second output, and a first clutching device having a first position and a second position, the first clutching device in the first position locking the inter-axle differential, engaging the first output with the input of the power distribution unit, and disengaging the second output from the inter-axle differential, the first clutching device in the second position unlocking the inter-axle differential and engaging the first output and the second output with the inter-axle differential; placing the first clutching device in one of the first position and the second position; applying a rotational force to the input of the power distribution unit; adjusting the rotational force transferred to the power distribution unit to facilitate moving the first clutching device; moving the first clutching device from one of the first position and the second position to a third position, the first clutching device in the third position neither locking the inter-axle differential nor engaging the second output with the inter-axle differential; adjusting a rotational speed of the input of the power distribution unit to facilitate moving the first clutching device from the third position; moving the first clutching device from the third position to one of the first and second positions; and adjusting the rotational force transferred to the power distribution unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of shifting a power distribution unit for a vehicle from a first operating state to a second operating state, the method comprising the steps of:
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drivingly engaging a first axle assembly with a first output of the power distribution unit; drivingly engaging a second axle assembly with a second output of the power distribution unit; drivingly engaging an input of the power distribution unit with an output of a power source, the power distribution unit including an inter-axle differential, the first output, the second output, and a first clutching device having a first position and a second position, the first clutching device in the first position locking the inter-axle differential, engaging the first output with the input of the power distribution unit, and disengaging the second output from the inter-axle differential, the first clutching device in the second position unlocking the inter-axle differential and engaging the first output and the second output with the inter-axle differential; placing the first clutching device in the first position; applying a rotational force to the input of the power distribution unit; one of reducing and interrupting the rotational force transferred to the power distribution unit; moving the first clutching device from the first position to a third position, the first clutching device in the third position unlocking the inter-axle differential; adjusting a rotational speed of the input of the power distribution unit to facilitate moving the first clutching device from the third position; adjusting a rotational speed of a first portion of the second axle assembly to a target speed, the target speed facilitating engagement between the first portion of the second axle assembly and a second portion of the second axle assembly; moving the first clutching device from the third position to the second position; and one of increasing and resuming the rotational force transferred to the power distribution unit. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A method of shifting a power distribution unit for a vehicle from a first operating state to a second operating state, the method comprising the steps of:
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providing a first axle assembly including a first pair of output axle shafts, a first differential drivingly engaged with the first pair of output axle shafts, and a first driving gear coupled to the first differential, the first axle assembly having a first gear ratio; providing a second axle assembly including a second pair of output axle shafts, a second differential selectively drivingly engaged with the second pair of output axle shafts, a second driving gear coupled to the second differential, and an inter-axle shaft drivingly engaged with the second driving gear, the second axle assembly having a second gear ratio; drivingly engaging an input of the power distribution unit with an output of a power source, the power distribution unit including an inter-axle differential, a first output drivingly engaged with the first driving gear, a second output drivingly engaged with the inter-axle shaft, and a first clutching device having a first position and a second position, the first clutching device in the first position locking the inter-axle differential, engaging the first output with the input of the power distribution unit, and disengaging the second output from the inter-axle differential, the first clutching device in the second position unlocking the inter-axle differential and engaging the first output and the second output with the inter-axle differential; placing the first clutching device in the first position; applying a rotational force to the input of the power distribution unit; one of reducing and interrupting the rotational force transferred to the power distribution unit; moving the first clutching device from the first position to a third position, the first clutching device in the third position neither locking the inter-axle differential nor engaging the second output with the inter-axle differential; adjusting a rotational speed of the input of the power distribution unit to facilitate moving the first clutching device from the third position; adjusting a rotational speed of the second output, the inter-axle shaft, the second driving gear, and the second differential to a target speed, the target speed facilitating engagement between the second differential and the second pair of output axle shafts; moving the first clutching device from the third position to the second position, the first clutching device in the second position engaging the second output with the inter-axle shaft, the second driving gear, and the second differential; one of increasing and resuming the rotational force transferred to the power distribution unit; distributing the rotational force between the first output and the second output through the inter-axle differential; and accommodating a rotational difference of the first output and the second output caused by a difference between the first gear ratio and the second gear ratio with the inter-axle differential, wherein the accommodating of the rotational difference between the first output and the second output provides a cumulative gear ratio for the first axle assembly and the second axle assembly, the cumulative gear ratio intermediate the first gear ratio and the second gear ratio. - View Dependent Claims (38, 39, 40, 41, 42)
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43. A method of shifting a power distribution unit for a vehicle from a first operating state to a second operating state, the method comprising the steps of:
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drivingly engaging a first axle assembly with an output of the power distribution unit; drivingly engaging an input of the power distribution unit with an output of a power source, the power distribution unit including the output and a first clutching device having a first position and a second position, the first clutching device in the first position engaging the output with the input of the power distribution unit and disengaging a portion of the power distribution unit, the first clutching device in the second position engaging the output; placing the first clutching device in one of the first position and the second position; applying a rotational force to the input of the power distribution unit; adjusting the rotational force transferred to the power distribution unit to facilitate moving the first clutching device; moving the first clutching device from one of the first position and the second position to a third position; adjusting a rotational speed of the input of the power distribution unit to facilitate moving the first clutching device from the third position; and moving the first clutching device from the third position to one of the first and second positions.
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44. A method of shifting a power distribution unit for a vehicle from a first operating state to a second operating state, the method comprising the steps of:
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drivingly engaging a first axle assembly with a first output of the power distribution unit; drivingly engaging a second axle assembly with a second output of the power distribution unit, the second axle assembly including an axle clutch, the axle clutch selectively disengaging a portion of one of a second pair of output axle shafts from a remaining portion of the one of the second pair of output axle shafts drivingly engaging an input of the power distribution unit with an output of a power source, the power distribution unit including an inter-axle differential, the first output, the second output, and a first clutching device having a first position and a second position, the first clutching device in the first position locking the inter-axle differential, engaging the first output with the input of the power distribution unit, and disengaging the second output from the inter-axle differential, the first clutching device in the second position unlocking the inter-axle differential and engaging the first output and the second output with the inter-axle differential; placing the first clutching device in the first position; applying a rotational force to the input of the power distribution unit; adjusting the rotational force transferred to the power distribution unit to facilitate moving the first clutching device; moving the first clutching device from the first position to a third position, the first clutching device in the third position neither locking the inter-axle differential nor engaging the second output with the inter-axle differential; imparting energy to a lubricant disposed within the second axle assembly by selectively engaging the axle clutch; adjusting a rotational speed of the input of the power distribution unit to facilitate moving the first clutching device from the third position; moving the first clutching device from the third position to the second position; and adjusting the rotational force transferred to the power distribution unit.
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Specification