Abstract: Two protrusions are disposed on the fixed contact along a lateral direction on a contacting surface. The two protrusions are disposed in a longitudinal direction with a predetermined interval on the contacting surface, and a planar portion is formed between the two protrusions. A single projection that intersects perpendicular to the two protrusions disposed on a first fixed contact and another single projection that intersects perpendicular to the two protrusions disposed on a second fixed contact are disposed on a movable contact. Thereby, when the movable contact contacts to a pair of fixed contacts, since the protrusions disposed on the fixed contact and the projections disposed on the movable contact contacts only at intersections of each other, a contacting surface pressure is increased and a crushing force for ice frozen on a surface of the fixed contact becomes large.

Abstract: Two protrusions are disposed on the fixed contact along a lateral direction on a contacting surface. The two protrusions are disposed in a longitudinal direction with a predetermined interval on the contacting surface, and a planar portion is formed between the two protrusions. A single projection that intersects perpendicular to the two protrusions disposed on a first fixed contact and another single projection that intersects perpendicular to the two protrusions disposed on a second fixed contact are disposed on a movable contact. Thereby, when the movable contact contacts to a pair of fixed contacts, since the protrusions disposed on the fixed contact and the projections disposed on the movable contact contacts only at intersections of each other, a contacting surface pressure is increased and a crushing force for ice frozen on a surface of the fixed contact becomes large.

Abstract: An electric rotary machine which may be employed as a dc motor in an automotive engine starter. The motor includes an armature equipped with an armature shaft, a commutator, brushes, and a bearing retaining an end of the armature shaft. The surface of the commutator has a plurality of protrusions extending in parallel to each other in a direction of rotation of the commutator. Each of the brushes has formed in the bottom thereof grooves in which the protrusions of the commutator are fit. The brushes are urged into constant engagement of the grooves with the protrusions on the commutator to establish electrical contacts between the brushes and the commutator and minimize movement of the armature shaft relative to the bearing.

Abstract: An electric rotating machine has a stator generating a magnetic flux and a rotor with a columnar armature core and an armature coil wound on the core. The flux passes through the rotor. The rotor is rotatable around its center axis. The core has slots aligned along its circumferential direction. Each slot extends along an axial direction of the core. The coil has upper layer coil parts and lower layer coil parts alternately connected with one another. Each pair of upper and lower layer coil parts is received in one slot so as to place the lower layer coil part nearer to the center axis of the core than the upper layer coil part. A sectional area of the upper layer coil part received in each slot is larger than a sectional area of the lower layer coil part received in the slot.

Abstract: A method of manufacturing a yoke includes a step of cutting a steel plate into a rectangular sheet having a plurality of first dovetail convexities at one end thereof and a plurality of second dovetail convexities at the other end, a step of rolling the rectangular sheet into a cylinder to fit the first dove tails and the second dove tails to each other and a step of punching border portions of the first dove tails and the second dove tails. The second dovetail convexities are formed to be the same in shape as the first dovetail convexities so that they can fit to the first dovetail convexities. A smooth-faced yoke can be manufacture without using an expensive welder.

Abstract: An electric rotary machine which may be employed as a dc motor in an automotive engine starter. The motor includes an armature equipped with an armature shaft, a commutator, brushes, and a bearing retaining an end of the armature shaft. The surface of the commurator has a plurality of protrusions extending in parallel to each other in a direction of rotation of the commutator. Each of the brushes has formed in the bottom thereof grooves in which the protrusions of the commutator are fit. The brushes are urged into constant engagement of the grooves with the protrusions on the commutator to establish electrical contacts between the brushes and the commutator and minimize movement of the armature shaft relative to the bearing.

Abstract: A method of manufacturing a yoke includes a step of cutting a steel plate into a rectangular sheet having a plurality of first dovetail convexities at one end thereof and a plurality of second dovetail convexities at the other end, a step of rolling the rectangular sheet into a cylinder to fit the first dove tails and the second dove tails to each other and a step of punching border portions of the first dove tails and the second dove tails. The second dovetail convexities are formed to be the same in shape as the first dovetail convexities so that they can fit to the first dovetail convexities. A smooth-faced yoke can be manufacture without using an expensive welder.

Abstract: A method of manufacturing a yoke includes a step of cutting a steel plate into a rectangular sheet having a plurality of first dovetail convexities at one end thereof and a plurality of second dovetail convexities at the other end, a step of rolling the rectangular sheet into a cylinder to fit the first dove tails and the second dove tails to each other and a step of punching border portions of the first dove tails and the second dove tails. The second dovetail convexities are formed to be the same in shape as the first dovetail convexities so that they can fit to the first dovetail convexities. A smooth-faced yoke can be manufacture without using an expensive welder.

Abstract: A starter is comprised of a starter motor, a planetary gear speed reduction mechanism including a sun gear, a plurality of planetary gears and an internal gear, a casing rotatably supporting the output shaft via a bearing and an outer cylindrical member coupled with the casing. The planetary gear speed reduction mechanism has an internal gear block having the internal gear, and the internal gear block is disposed in the cylindrical member and spline-fitted to the casing. Thus, a labyrinth is formed between the internal gear block and the casing.

Abstract: In a planetary gear speed reduction mechanism includes a drive gear, a driven gear, a sun gear connected to the drive gear, an internal gear disposed around the sun gear, a planetary gear meshed with the sun gear and the internal gear, a bearing for supporting the planetary gear, a carrier pin for supporting the bearing and a planet carrier connected to the carrier pin for transmitting revolving motion of the planetary gear to the driven gear, the bearing has a cylindrical inner wall forming an annular grease reservoir around the carrier pin at opposite ends thereof. The bearing can be lubricated by the grease supplied from the simple grease reservoir for long time.

Abstract: A starter is comprised of a starter motor, a planetary gear speed reduction mechanism including a sun gear, a plurality of planetary gears and an internal gear, a casing rotatably supporting the output shaft via a bearing and an outer cylindrical member coupled with the casing. The planetary gear speed reduction mechanism has an internal gear block having the internal gear, and the internal gear block is disposed in the cylindrical member and spline-fitted to the casing. Thus, a labyrinth is formed between the internal gear block and the casing.

Abstract: An armature is constructed by installing a lower layer coil and an upper layer coil in double layers in each slot provided on an armature core. A straight portion of the upper layer coil installed in the slot includes coil end portions at both side ends, which protrude from both axial end surfaces of the armature core in an axial direction. A liquid resin is filled in an inner groove defined among adjacent coil end portions in a peripheral direction, the axial end surface of the armature core and an outer insulating plate. Also, a cylindrical body (non-magnetic material) is mounted on an outer periphery of the coil end portions. Accordingly, brush powder is restricted from entering the inner groove, and a creeping distance for insulation between the armature core, the lower layer coil, and the upper layer coil can be secured.

Abstract: In a planetary gear speed reduction mechanism includes a drive gear, a driven gear, a sun gear connected to the drive gear, an internal gear disposed around the sun gear, a planetary gear meshed with the sun gear and the internal gear, a bearing for supporting the planetary gear, a carrier pin for supporting the bearing and a planet carrier connected to the carrier pin for transmitting revolving motion of the planetary gear to the driven gear, the bearing has a cylindrical inner wall forming an annular grease reservoir around the carrier pin at opposite ends thereof. The bearing can be lubricated by the grease supplied from the simple grease reservoir for long time.

Abstract: A method of manufacturing a yoke includes a step of cutting a steel plate into a rectangular sheet having a plurality of first dovetail convexities at one end thereof and a plurality of second dovetail convexities at the other end, a step of rolling the rectangular sheet into a cylinder to fit the first dove tails and the second dove tails to each other and a step of punching border portions of the first dove tails and the second dove tails. The second dovetail convexities are formed to be the same in shape as the first dovetail convexities so that they can fit to the first dovetail convexities. A smooth-faced yoke can be manufacture without using an expensive welder.

Abstract: A pole arrangement of a motor includes a plurality of permanent-magnet main poles disposed annularly at equal intervals on the inner periphery of a yoke, a plurality of auxiliary poles disposed between adjacent two of the main poles, and a plurality of magnet holders disposed between adjacent two of the main poles. Each the magnet holder is comprised of at least one resilient stopper member for pressing the main poles in the circumferential direction, and each the auxiliary pole is held between the pair of resilient stoppers.

Abstract: A drain pipe connected to a casing includes a water inlet opening and a couple of water outlet openings. The inlet opening is arranged at an upper end part of the drain pipe and is communicated to an internal space of the casing. The outlet openings are arranged at a lower end part of the drain pipe and extend laterally of the drain pipe in opposite directions, respectively. The drain pipe further includes a cylindrical outer wall that defines an interior space therein. The interior space communicates the water inlet opening with the water outlet openings. A partition wall is provided within the interior space of the cylindrical outer wall to divide at least a portion of the interior space of the cylindrical outer wall into two compartments. Each one of the water outlet openings is provided to each corresponding one of the compartments.

Abstract: A drain pipe connected to a casing includes a water inlet opening and a couple of water outlet openings. The inlet opening is arranged at an upper end part of the drain pipe and is communicated to an internal space of the casing. The outlet openings are arranged at a lower end part of the drain pipe and extend laterally of the drain pipe in opposite directions, respectively. The drain pipe further includes a cylindrical outer wall that defines an interior space therein. The interior space communicates the water inlet opening with the water outlet openings. A partition wall is provided within the interior space of the cylindrical outer wall to divide at least a portion of the interior space of the cylindrical outer wall into two compartments. Each one of the water outlet openings is provided to each corresponding one of the compartments.

Abstract: A DC motor includes an armature, an armature shaft, a commutator, a plurality of brushes in contact with the commutator, a plurality of brush springs for respectively biasing the brushes against the commutator, and a brush holder unit for holding the pair of brushes. Each of the brush springs comprises a springy spring body disposed at a side of corresponding one of the brushes and a spring arm extending from the spring body to bias the rear end of the corresponding one of the brushes against the commutator, and the spring body has an outer periphery disposed within the axial length of the corresponding one of the brushes.

Abstract: To reduce the size of a starter for installing it in a smaller engine compartment, the rotational speed of the starter motor has to be high and it is reduced to a certain speed through a reduction device to obtain a higher torque. To realize a high reduction ratio in a small planetary gear reduction device, an impact force imposed on the device at an instant a starter pinion engages with a engine ring gear and repeating impacts during a cranking period must be reduced. As a coupling between an internal gear and a housing of the reduction device, a flexible or a resilient coupling is disclosed herein. The flexible or resilient coupling relieves an excessive impact force at the engagement by permitting rotation of the internal gear relative to the housing, and reduces noise caused by the cranking impacts by permitting a small vibrating move of the internal gear. The flexible coupling is realized by a combination of a bumpy surface and projections coupled thereto.

Abstract: A separating wall comprised of a slanting portion, an anti-falling portion and a thrust receiving portion, is provided integrally with a yoke. The slanting portion is formed from the front end of the yoke to the side of a speed reduction mechanism, tilting in the inner radial direction. The anti-falling portion is formed extending substantially vertically from the slanting portion to the inner radial direction preventing planetary gears of the speed reduction mechanism from coming-off mounting pins, by way of contacting the pins supporting the planetary gears and the end surface of a bearing. The thrust receiving portion supports a shaft rotatably via a bearing fitted with the shaft and receives thrust load of the shaft. The thrust receiving portion is cylindrically shaped and bent from the anti-falling portion to the side of an armature core. The cylindrical portion of the thrust receiving portion is pressed and fitted around the outer periphery of the bearing fitted to the shaft.