Collapsible steering column apparatus of a motor vehicle

A collapsible steering column apparatus of a motor vehicle, comprising:

• a steering wheel having a hollow portion therein, being comprised of a material which has an allowable stress in the ranged of 30 PSI to 100 PSI;
• a first steering column having both ends being opened, an upper end to which said steering wheel is fixed, a first spline formed at the lower inner peripheral surface thereof and a first flange formed at a tip of the first spline;
• a second steering column having both ends being opened, a second spline formed in upper outer peripheral surface and slidably engaged with the first spline, a third spline formed on lower inner peripheral surface, a fourth spline formed on lower outer peripheral surface, and a third flange formed at the tips of the third and fourth splines;
• a third steering column having one end being opened, a fifth spline formed on upper outer peripheral surface and slidably engaged with the third spline, and a fourth flange formed at the tip of said fifth spline;
• a fourth steering column having one end being opened, a sixth spline formed on upper inner peripheral surface and slidably engaged with the fourth spline, and a fifth flange formed at tip of the sixth spline;
• a plurality of first balls inserted between the first spline of said first steering column and the second spline of said second steering column;
• a plurality of second balls inserted between the third spline of said second steering column and the fifth spline of said third steering column;
• a plurality of third balls inserted between the fourth spline of said second steering column and the sixth spline of said fourth steering column;
• a bellows for sealing said first, second, third and fourth column by fixing an internal side of a first end thereof on the lower outer peripheral surface of said first steering column and an internal side of a second end thereof on the upper outer peripheral surface of said fourth steering column, and being comprised of a material endurable against at least about 30 atmospheric pressure;
• a collision sensor installed in front of said motor vehicle for detecting a collision of said motor vehicle to generate a collision signal;
• a pressure sensor installed in the inside of said steering column part for detecting the internal pressure of said first, second, third and fourth steering columns to generate a pressure signal;
• a reservoir for compressing and storing the gas;
• a first pipe whose one end is connected to said reservoir;
• a second pipe whose one end is connected through said first and second steering columns;
• a solenoid valve whose first end is connected to said first pipe and whose second end is connected to said second pipe for supplying the gas of said reservoir to the inside of said first, second, third and fourth steering columns, for maintaining the internal pressure of said first, second, third and fourth steering columns to a predetermined level, and for exhausting the gas in said first, second, third and fourth steering columns in order to decrease the internal pressure thereof;
• a controller for controlling said solenoid valve so as to exhaust the gas of said first, second, third and fourth steering columns when the collision signal is received from said collision sensor, for controlling said solenoid valve so as to supply the gas in said reservoir to said first, second, third and fourth steering columns simultaneously with generating an alarm signal by receiving said pressure signal from said pressure sensor when the pressure in said steering column part is lowered below the predetermined level, and for controlling said solenoid valve so as to maintain the pressure of said first, second, third and fourth steering columns at the predetermined level by means of receiving the pressure signal from said pressure sensor when the pressure of said first, second, third and fourth steering columns is reached at the predetermined level;
• and
• an alarm lamp for alarming a driver, said alarm lamp being operated by the alarm signal;
• whereby a movement of said first steering column is restricted by the first balls, the first flange and third flange, and movement of said second steering column is restricted by the second balls, the third balls, the third flange and the fourth flange.