US 4,702,123 A · Apparatus for driving rod for rotation

Abstract

A rod actuator which includes a d.c. motor, a reduction gearing, a solenoid assembly which is used to define an intermediate stop position, and rotation stops. The angular extent through which an output shaft of the reduction gearing is rotatable is limited by a pair of limit stops. The solenoid assembly includes a plunger which is located intermediate the limit stops. A rotational stop is rotatably mounted on the output shaft and has a projection which is adapted to abut against the plunger to cease the motion of the rotational stop. The rotational stop is mounted on the output shaft so as to be rotatable relative thereto through a small angle by a lost motion, but is driven for integral rotation with the output shaft when such angle is exceeded. A lost motion connector is used so the angles of rotation where the rotation of the output shaft is stopped by the plunger during its clockwise and counter-clockwise rotations will be substantially equal. The actuator may be used in a shock absorber mounted on a vehicle to establish three levels, "high", "medium" and "low", of attenuation exhibited by the shock absorber.

An apparatus for driving rod for rotation comprising:

a support member;
a d.c. motor having a rotary shaft carried by the support member;
a solenoid assembly carried by the support member and including a fixed core member, a plunger member, a spring member for urging the plunger member and an electrical coil which surrounds the fixed core member, the arrangement being such that the plunger member is driven to a first position against the resilience of the spring member when the electrical coil is energized and the plunger member is located at a second position which is spaced from the first position when the electrical coil is deenergized;
output shaft means rotatably mounted in the support member;
reduction gearing means interposed between the rotary shaft of the motor as an input shaft thereof and the output shaft means as an output rotating shaft thereof for providing a speed reduction of rotation of the d.c. motor before it is transmitted to the output shaft means;
a rotatable member rotatably mounted on one of the rotating shafts of the reduction gearing and including projection means which abuts the plunger member in said first position and which does not abut against the plunger member in the said second position;
lost motion coupling means for coupling the rotatable member to the rotating shaft in a manner to permit a rotation of the rotatable member within a given small angel while preventing a rotation of the rotatable member beyond the given angle;
a first stop member for preventing a rotation of the rotating shaft in a first direction at an angle of rotation where the projection means has rotated through the given angle beyond the position of the plunger member, and a second stop member for preventing a rotation of the rotating shaft in a second direction which is opposite from the first direction at an angle of rotation where the projection means has rotated through the given angle beyond the position of the plunger;
wherein said small angle is represented by .alpha., an angle subtended with respect to the center of rotation of the projection means by a first point on the projection means where it abuts against the plunger member in its first position which is assumed as a result of its rotation in the first direction and a second point on the projection means where it abuts against the plunger member at its first position which is assumed as a result of rotation in the second direction by .beta., and an angle subtended by a pair of points on the plunger member which correspond to the first and the second point with respect to the center of rotation of the projection means by .gamma., .alpha. is substantially equal to (.beta.+.gamma./2);
and
wherein said reduction gearing means comprises a small gear fixedly mounted on the rotary shaft of the d.c. motor and a larger gear fixedly mounted on the output shaft means and meshing with the small gear, the larger gear being formed in its lower surface with an annular groove in which the rotatable member is rotatably mounted, and in which the support member comprises a base located above the small and the larger gear and carrying the d.c. motor and the solenoid assembly thereon and also rotatably carrying the output shaft means and having an opening through which the plunger member extends, the lost motion coupling means comprising a fan-shaped groove formed in the larger gear so as to be continuous with the annular groove, the projection means on the rotatable member engaging the fan-shaped groove which permits the projection means to rotate therein through the given small angle.

8 more elements

Apparatus for driving rod for rotation

Life of this patent

Apparatus for driving rod for rotation

Life of this patent

Abstract

Claims18