Abstract: An engine starter comprises a DC motor having a hollow armature rotation shaft, a drive force transmitting device for transmitting a drive force generated by the DC motor, the drive force transmitting device includes a planetary gear speed reducer connected to the armature rotation shaft axially slidably received in a hollow portion of the armature rotation shaft, the output rotation shaft having a helical spline portion engaged with a helical spline portion of the overrunning clutch device, a pinion mounted on a front end of the output rotation shaft to engage a ring gear of an engine and spring device, provided adjacent to a side face of said pinion, for urging said pinion forwardly.

Abstract: A starter motor comprises an oil seal of resilient sheet material disposed between a bearing supporting a pinion slider and a front frame portion having an opening in which the bearing is supported and in resilient contact with the slidable support surface and an annular metal holder having an angled U shape cross section and fixedly secured to the slidable support surface with a valley portion thereof facing to the bearing and an annular lip extending forwardly from a peripheral edge of the opening so that it enters into the valley portion of the holder when the pinion slider is in a rest position. At least one drain is formed in an outer wall of the front frame portion and extends along the oil seal. The oil seal of resilent material may have a generally T shape cross section with a lateral bar portion thereof being used as the oil seal and a vertical bar portion thereof being used as the annular lip. A drain hole may be formed in the vertical bar portion.

Abstract: A starter motor comprising a pinion (3) which engages at an inner circumference of a gear portion thereof with an outer circumference of an output rotary shaft (4), and a cylindrical member (15) integrally disposed behind the pinion. A front end portion of a clutch inner member (9b) of an over-running clutch unit (9) is in sliding abutment with an outer circumferential surface of the cylindrical member, and the inner circumferential surface of the cylinder member is in splined engagement with the output rotary shaft.

Abstract: A coaxial type starter device comprises an overrunning clutch device having a clutch inner member and a pinion shaft with a pinion at an end, the pinion shaft being inserted in the clutch inner member so as to be engageble therewith by helical splines formed at the pinion shaft and the clutch inner member so that a torque is transmitted from the clutch inner member to the pinion shaft and a radial load by the pinion shaft is borne by the helical spline of the clutch inner member, wherein the helical splines of the clutch inner member and the pinion shaft have radially contacting portions wherein the outer surfaces of the teeth of the helical spline of the clutch inner member are in slide-contact with the corresponding parts of the helical spline of the pinion shaft, and have radially non-contacting portions wherein the other portions of the helical spline of the clutch inner member face, with gaps, the corresponding parts of the helical spline of the pinion shaft, and wherein the total surface area of the rad

Abstract: A coaxial engine starter comprising an electric motor having an armature rotary shaft 23, an output rotary shaft 5 axially slidably supported in an axial alignment relationship with the armature rotary shaft and a pinion 10 disposed on the front end of the output rotary shaft. The starter also comprises a planetary speed reduction gear 7 having a sun gear disposed on the armature rotary shaft, a plurality of planetary gears rotatable around the sun gear and a stationary internal gear engaging the planetary gear, and an over-running clutch 21 having a clutch outer member supporting the planetary gears and a clutch inner member slidably coupled to the output rotary shaft and having front and rear ends. The clutch inner member is rotatably supported at its front end by a first bearing 11 supported by the machine frame 8 and at its rear end by a second bearing 25 mounted on the armature rotary shaft in front of the sun gear of the planetary speed reduction gear.

Abstract: A magnetic switch wherein a core flange 22a is so formed as to always confront the outer peripheral surface of a cylindrical plunger 23 while the plunger is being shifted in a direction from the flange to another core member 4a by the magnetic attraction force, thereby to prevent the magnetic attraction force from generating in a direction reverse to that the plunger is to be shifted.

Abstract: An electromagnetic switch device for a starter motor has a plunger 21 defining a cylindrical body 22 slidably fitted in a sleeve 8, and a trumpet shaped intermediate plate 23 which generally extends in a plane perpendicular to the central axis of the cylindrical body. At least part of the cylindrical body has a thin-walled portion which extends in a direction opposite the extension direction of a cylindrical rod 24 driven by the plunger, from a junction 21a to the radially outer portion of the intermediate plate.

Abstract: A coaxial type starter comprises a motor having a tubular armature rotary shaft, an electromagnetic switch located at the rear part of the motor and having an operating shaft arranged in the same axial line as the armature shaft, an overrunning clutch for transmitting a rotating force only in one direction, and a pinion shaft which is disposed in the armature shaft to receive the rotating force thereof through the overrunning clutch. The front end portion of a clutch inner member in the overrunning clutch device is supported by a bearing which is fitted to a front bracket; the pinion shaft is so arranged that it is engaged with the inner circumference of the clutch inner member through a spline, and pinion teeth formed at the front end of the pinion shaft are radially overlapped by the bearing.

Abstract: An engine starter apparatus being arranged such that a rotational force from an electric motor is transmitted to an output rotary shaft through a planetary speed reduction gear. The number Zs of teeth of a sun gear, the number Zp of teeth of a planet gear, the number Zi of teeth of an internal gear and the number N of the planet gears satisfy the equation (Zs+Zi)N=an integer, and the pressure angle .alpha.bi of the engagement between the planet gear and the internal gear is arranged to be cos.sup.-1 {(Zi-Zp)/(Zs+Zp).times.cos.alpha.bs}, where .alpha.bs is the pressure angle of the engagement between the sun gear and the planet gear.