Electric actuator of automotive pivotal door
A case is mounted to one of a motor vehicle and a pivotal door and has therein a gear receiving space. An electric motor is mounted to the case. A speed reduction mechanism is installed in the gear receiving space of the case and driven by the electric motor. An output gear is rotatably received in the gear receiving space of the case and driven by the speed reduction mechanism. An output arm is placed above the case and connected to the output gear through an output shaft that passes through an upper wall portion of the case. A connecting rod has one end pivotally connected to the output arm and the other end pivotally connected to the other of the motor vehicle and the pivotal door. The connecting rod is arranged beside the case in a manner to avoid overlapping thereof with the case in a direction that is perpendicular to a direction in which the connecting rod is moved by the output arm.
1. An electric actuator for actuating a pivotal door of a motor vehicle, comprising:
a case mounted to one of the motor vehicle and the pivotal door, the case having therein a gear receiving space;
an electric motor mounted to the case;
a speed reduction mechanism installed in the gear receiving space of the case and driven by the electric motor;
an output gear rotatably received in the gear receiving space of the case and driven by the speed reduction mechanism;
an output arm placed above the case and connected to the output gear through an output shaft that passes through an upper wall portion of the case; and
a connecting rod having one end pivotally connected to the output arm and an other end pivotally connected to the other of the motor vehicle and the pivotal door,
wherein the connecting rod is arranged beside the case in a manner to avoid overlapping thereof with the case in a direction that is perpendicular to a direction in which the connecting rod is moved by the output arm,
wherein the speed reduction mechanism includes:
a pinion driven by the electric motor; and
an intermediate gear having a larger diameter gear part meshed with the pinion and a smaller diameter gear part meshed with the output gear,
wherein the pinion, the intermediate gear, and the output gear are arranged in tandem on an imaginary straight line that is generally in parallel with the direction in which the connecting rod is moved by the output arm,
wherein the electric motor is arranged on an extension part of the imaginary straight line, and
wherein the electric motor has an output shaft whose axis is inclined relative to the imaginary straight line, so that the electric motor has a reduced dimension in a direction that is perpendicular to the imaginary straight line.
2. An electric actuator as claimed in claim 1 , further comprising an electromagnetic clutch that is mounted to the upper wall portion of the case to selectively open and close a power transmission path defined by the speed reduction mechanism.
3. An electric actuator as claimed in claim 2 , in which the electromagnetic clutch comprises:
an annular electromagnet that surrounds an input shaft;
a rotor secured to the input shaft to rotate therewith; and
an armature that rotates together with a worm wheel meshed with a worm driven by the electric motor, the armature being rotatably and axially movably held by the input shaft while facing the rotor.
4. An electric actuator as claimed in claim 1 , further comprising a universal joint by which the output arm and the connecting rod are pivotally connected, the universal joint having a thickness smaller than that of the case.
5. An electric actuator as claimed in claim 4 , in which the universal joint comprises:
a spherical pin provided to a lower surface of an outer end of the output arm; and
a spherical grip portion provided on an end of the connecting rod, wherein the spherical pin is rotatably received in the spherical grip portion.