| 摘要 |
An improved shift motor assembly for selectively moving a shift rod or similar member between two gear-engaging positions for use, for example, in a two-speed axle assembly is disclosed. The assembly includes a mechanism for limiting the amount of linear movement of a drive nut of a gear changing apparatus. The movement limiting mechanism interrupts an electrical circuit between a source of electrical energy and a bi-directional motor utilized to move the drive nut, thereby preventing linear movement of the drive nut beyond predetermined limit positions in either directions. The movement limiting mechanism includes a movable electrical contact which normally engages a stationary electrical contact. The movable and stationary electrical contacts form a single pole, single throw electrical switch which is connected in series between the source of electrical energy and the motor. When the dirve nut is moved in a first linear direction to a predetermined limit position, it engages the movable electrical contact and moves such contact out of engagement with the stationary electrical contact. As a result, the motor is disabled from further moving the drive nut from being further moved in the first direction. A second movable electrical contact and a second stationary electrical contact are provided to limit the linear movement of the drive nut in a second linear direction, opposite to the first direction. |
