Four-wheel drive vehicle operating system
First Claim
1. In an operating system used in a vehicle equipped with four-wheel drive having a center-differential which is shiftable between a differential-locked and a differential-free drive mode of operation and between a two-wheel and a four-wheel drive mode of operation, and a free-wheeling device with a clutch means incorporated in an output shaft of an axle differential in association with wheels which are non-driven when the vehicle is in said two-wheel drive mode of operation, said clutch means being adapted to disconnect the transmission of driving power between said axle differential and said non-driven wheels when the vehicle is in said two-wheel drive mode of operation and to connect a transmission of driving power between said axle differential and said wheels when the vehicle is in said four-wheel drive mode of operation, the improvement comprising:
- transfer case shift means operable between at least two positions for selecting said two-wheel drive mode and four-wheel, differential-free drive mode; and
shift control means responsive to an operation of said transfer case shift means for shifting said center-differential to from one to the other between said two-wheel drive mode and four-wheel, differential-free drive mode, said shift of drive mode of said center-differential being accompanied by an intermediate transition of said center-differential to a differential-locked drive mode.
1 Assignment
0 Petitions
Accused Products
Abstract
An operating system used in a vehicle equipped with a part-time four-wheel drive comprises; a center-differential shiftable between at least a two-wheel drive mode and a four-wheel differential-locked drive mode; a free-wheeling device with a clutch mechanism incorporated in an output shaft of an axle differential associated with wheels which are rendered non-driven when the vehicle is traveling in the two-wheel drive mode and adapted to connect and disconnect the transmission of driving power between the axle differential and the non-driven wheel; a drive mode selecting member operated by a driver in the driver'"'"'s compartment to select a desired driving mode of operation of the center-differential; and a shift control device which sequentially shifts the center-differential responding to an operation of the drive mode selecting member. The shift control device controls the center-differential to be intermediately shifted into a four-wheel differential-locked drive mode upon being shifted from one to the other between the two-wheel and four-wheel differential-locked drive modes. The shift control device shifts finally the center-differential into the other drive mode after locking the clutch mechanism to connect the transmission of driving power between the axle differential and the wheel which is rendered non-driven when the center-differential is traveling in two-wheel drive mode.
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Citations
12 Claims
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1. In an operating system used in a vehicle equipped with four-wheel drive having a center-differential which is shiftable between a differential-locked and a differential-free drive mode of operation and between a two-wheel and a four-wheel drive mode of operation, and a free-wheeling device with a clutch means incorporated in an output shaft of an axle differential in association with wheels which are non-driven when the vehicle is in said two-wheel drive mode of operation, said clutch means being adapted to disconnect the transmission of driving power between said axle differential and said non-driven wheels when the vehicle is in said two-wheel drive mode of operation and to connect a transmission of driving power between said axle differential and said wheels when the vehicle is in said four-wheel drive mode of operation, the improvement comprising:
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transfer case shift means operable between at least two positions for selecting said two-wheel drive mode and four-wheel, differential-free drive mode; and shift control means responsive to an operation of said transfer case shift means for shifting said center-differential to from one to the other between said two-wheel drive mode and four-wheel, differential-free drive mode, said shift of drive mode of said center-differential being accompanied by an intermediate transition of said center-differential to a differential-locked drive mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of operating a part-time four-wheel drive vehicle having a center-differential shiftable between two-wheel and four-wheel drive modes and between differential-locked and differential-free drive modes, and a free-wheeling device with clutch means incorporated in an output shaft of an axle differential associated with wheels which are non-driven when the vehicle is in the two wheel drive mode, said clutch means being adapted to disconnect the transmission of driving power between an input shaft of the center-differential and an output shaft of the axle differential when the vehicle is in said two-wheel drive mode and to connect the transmission of driving power between an output of the center-differential and an output shaft of said axle differential when the vehicle is in said four-wheel drive mode, comprising the steps of:
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providing a shift control signal for shifting said center-differential from said two-wheel to said four-wheel differential-free drive mode; actuating control means responding to the provision of said shift control signal to shift said center-differential into said four-wheel differential-locked drive mode from said two-wheel drive mode and to provide a differential lock signal when said shifting is accomplished; locking said clutch means of said free-wheeling device responding to the provision of said differential lock signal; providing a clutch lock signal when said locking is accomplished; and actuating said control means responding to the provision of said clutch lock signal to shift said center-differential into said four-wheel differential-free drive mode from said four-wheel differential-locked drive mode.
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12. A method of operating a part-time four-wheel drive vehicle having a center-differential shiftable between two-wheel and four-wheel drive modes and between differential-locked and differential-free drive modes, and a free-wheeling device with clutch means incorporated in an output shaft of an axle differential associated with wheels which are non-driven when the vehicle is in the two wheel drive mode, said clutch means being adapted to disconnect the transmission of driving power between an input shaft of the center-differential and an output shaft of the axle differential when the vehicle is in said two-wheel drive mode and to connect the transmission of driving power between an output of the center-differential and an output shaft of said axle differential when the vehicle is in said four-wheel drive mode, comprising the steps of:
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providing a shift control signal for shifting said center-differential from said four-wheel differential-free to said two-wheel drive mode; actuating control means responding to the provision of said shift control signal to shift said center-differential into said four-wheel differential-locked drive mode from said four-wheel differential-free drive mode and to provide a differential lock signal when said shifting is accomplished; unlocking said clutch means of said free-wheeling device responding to the provision of said differential lock signal; providing a clutch unlock signal when said unlocking is accomplished; and actuating said control means responding to the provision of said clutch unlock signal to shift said center-differential into said two-wheel drive mode from said four-wheel differential-locked drive mode.
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Specification