| 摘要 |
The housing of a starting motor rotatably mounts a cylinder having internal splines of one pitch. A shaft having external splines of a different pitch is rotatably and translatably supported by both the cylinder and housing and is connected at one end to a pinion engageable with the starter gear of an engine. Supported by the splines on the cylinder and the shaft are respectively a plunger and a nut that are advanced towards the pinion end of the shaft by the coaction of the cylinder and shaft with their respective different sets of splines. The plunger and nut are coupled by an axially acting clutch engaged by the translation of the plunger towards the pinion end and by a rotatably acting clutch engaged by rotation of the shaft relative to the cylinder. The rotatably acting clutch is disengaged by rotation of the shaft relative to the cylinder in the other direction or by the engagement of the axially acting clutch. Compressed between the nut and the pinion is a helical jump spring that not only translates the pinion when the nut is translated by the plunger but also allows the rotatably acting clutch to be disengaged should the teeth of the pinion abut those of the engine starter gear or should the engine starter gear drive the pinion rather than be driven by it. The jump spring also urges the pinion forward to engage the starter gear after the abutment has been eliminated. When the engine has started, the inertial interaction between the cylinder and plunger and a preload on the rotatably acting clutch retracts the plunger to engage another axially acting clutch that in turn retracts the pinion from engagement with the starter gear.
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