Four wheel drive vehicle

A four wheel drive vehicle comprising;

• an engine,
• front wheels and rear wheels driven by said engine, said front wheels being dirigible,
• propelling drive transmission means for producing at least two, high and low, speeds,
• a front wheel change speed mechanism for receiving power from said propelling drive transmission means, said front wheel change speed mechanism including a first transmission mechanism for producing a standard speed, a second transmission mechanism for producing a high speed, and a first switching means for selecting between said first and second transmission mechanisms,
• a rear wheel change speed mechanism for receiving power from said propelling drive transmission means, said rear wheel change speed mechanism including a third transmission mechanism for producing the standard speed, a fourth transmission mechanism for producing a low speed, and a second switching means for selecting between said third and fourth transmission mechanisms,
• said first and third transmission mechanisms in combination producing a speed mode in which said front and rear wheels are driven at the same speed, said first and fourth transmission mechanisms in combination producing a low speed mode in which said front wheels are accelerated, and said second and third transmission mechanisms in combination producing a high speed mode in which said front wheels are accelerated, and
• control means for controlling said first and second switching means, said control means receiving information regarding change speed positions of said propelling drive transmission means and steering positions of said front wheels,
• wherein said control means controls said first and second switching means to select said first and third transmission mechanisms when a steering angle of said front wheels exceeds a predetermined angle and said propelling drive transmission means is in a low speed position, to select said first and fourth transmission mechanisms when the steering angle of said front wheels exceeds said predetermined angle and said propelling drive transmission means is in a high speed position, and to select said first and second transmission mechanisms when the steering angle of said front wheels is below said predetermined angle.

A four wheel drive vehicle comprising;

• an engine,
• front wheels and rear wheels driven by said engine, said front wheels being dirigible,
• propelling drive transmission means for producing at least two, high and low, speeds,
• a front wheel change speed mechanism for receiving power from said propelling drive transmission means, said front wheel change speed mechanism including a first transmission mechanism for producing a standard speed, a second transmission mechanism for producing a high speed, and a first switching means for selecting between said first and second transmission mechanisms,
• a rear wheel change speed mechanism for receiving power from said propelling drive transmission means, said rear wheel change speed mechanism including a third transmission mechanism for producing the standard speed, a fourth transmission mechanism for producing a low speed, and a second switching means for selecting between said third and fourth transmission mechanisms,
• said first and third transmission mechanisms in combination producing a speed mode in which said front and rear wheels are driven at the same speed, said first and fourth transmission mechanisms in combination producing a low speed mode in which said front wheels are accelerated, said second and third transmission mechanisms in combination producing a high speed mode in which said front wheels are accelerated, and said second and fourth transmission mechanisms in combination producing a sharp turn mode in which said front wheels are accelerated,
• a sharp turn permitting switch, and
• control means for controlling said first and second switching means, said control means receiving information regarding change speed positions of said propelling drive transmission means, steering positions of said front wheels, and positions of said sharp turn permitting switch,
• wherein said control means controls said first and second switching means to select said first and third transmission mechanisms when a steering angle of said front wheels exceeds a predetermined angle and said propelling drive transmission means is in a low speed position, to select said first and fourth transmission mechanisms when the steering angle of said front wheels exceeds said predetermined angle and said propelling drive transmission means is in a high speed position, to select said first and second transmission mechanisms when the steering angle of said front wheels is below said predetermined angle, and to select said second and fourth transmission mechanisms only when said sharp turn permitting switch is in an ON position and the steering angle of said front wheels exceeds said predetermined angle.