JP2010154704A - Electric motor and engine starting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure the installation effect of an auxiliary pole by improving the contact state of the auxiliary pole and the inner circumferential surface of a yoke in an electric motor with an auxiliary pole without spoiling the machinability or mountability. <P>SOLUTION: The electric motor 2 used as the drive source of the engine starting device has a motor housing 21, a plurality of magnets 26 fixed to the inner circumferential surface 21a thereof, and the auxiliary pole 87 arranged contiguously to the magnetizing side of the magnets 26. The auxiliary pole 87 is constituted by laminating a plurality of metal plates 88 formed of a magnetic body. The auxiliary pole 87 is fixed to the inside of the motor housing 21 so that the corner 88a of each metal plate 88 touches the inner circumferential surface 21a of the motor housing. Since the auxiliary pole 87 comes into multipoint contact with the inner circumferential surface 21a of the motor housing, contact points of the motor housing 21 and the auxiliary pole 87 increase to facilitate conduction of magnetic flux between them. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric motor in which an auxiliary pole is added to a field magnet, and more particularly to an electric motor used as a drive source for an engine starting device such as an automobile.

  Conventionally, in a DC electric motor, a permanent magnet (magnet) is generally used as a field pole. For example, an electric motor of a magnet field is also used in an engine starter (starter) for starting an engine of an automobile, a motorcycle, a large generator, etc., and Patent Document 1 discloses a pinion gear by the rotational force of this motor. An engine starting device of a type in which is moved in the axial direction and meshed with an engine ring gear is described.

  Such an engine starter rotates a crankshaft in a stopped state when starting the engine, and thus requires a large rotational torque. On the other hand, after the engine starts to rotate once, it is necessary to drive the engine at a high speed and quickly bring the engine into a normal operation state in order to suppress generation of raw gas. For this reason, the motor that is the driving source is required to have high performance in the high current region at the time of startup and high rotation in the low current region after the startup. However, when a normal magnet field motor is a high torque type, a high magnetic flux is set and the rotational speed is reduced, and when a high rotation type is used, a low magnetic flux is set and a torque is reduced. That is, the setting of high current-high torque / low current-high rotation has a trade-off relationship that is difficult to achieve at the same time. For this reason, there is a problem that it is difficult to obtain a suitable magnet motor for an engine starting device.

Therefore, in order to satisfy such a trade-off relationship, a motor has been proposed in which an auxiliary pole is provided adjacent to the magnet so as to obtain performance suitable for the starter, as in the starter of Patent Document 2. There, an auxiliary pole made of a magnetic material having a reversible permeability higher than that of the magnet is arranged on the magnet's magnetizing side, which increases torque in a high current region and increases rotation in a low current region. It is illustrated. In such a motor with an auxiliary pole, the armature magnetic flux passes through the auxiliary pole in a high current range, and thereby the auxiliary pole is magnetized and magnetized so that a high magnetic flux is obtained and a high torque type setting is obtained. Become. On the other hand, since the armature magnetic flux does not pass through the auxiliary pole in the low current region, the magnet is cut by the amount corresponding to the auxiliary pole, thereby resulting in a low magnetic flux state and a high rotation type setting. That is, by adding the auxiliary pole, it is possible to realize an optimum setting for the engine starting device of high current-high torque / low current-high rotation.
JP 2005-127244 A JP 58-153558 A JP 58-6061

  On the other hand, in such a motor with auxiliary poles, considering the workability of the auxiliary poles and the assembling characteristics of the motors, it is preferable that the auxiliary poles themselves have a rectangular symmetrical shape to eliminate the directionality during the assembling. As a result, the assembly work of the auxiliary electrode is facilitated, the problem of erroneous assembly does not occur, and the number of assembly steps and defective products can be reduced. However, if the auxiliary pole is set in this way, as shown in FIG. 5, when the auxiliary pole 101 is attached to the yoke 102, the auxiliary pole 101 contacts the yoke inner peripheral surface 102a at the left and right corner portions 101a. Then, the auxiliary pole 101 and the yoke 102 are in point contact, and a gap G is formed between the auxiliary pole and the yoke. When such a point contact state is established between the auxiliary pole and the yoke, the flow of magnetic flux between the two is limited, and as a result, there arises a problem that reluctance torque cannot be obtained by the auxiliary pole.

  In this case, if the end surface of the auxiliary pole 101 is formed in a curved shape so as to match the yoke inner peripheral surface 102a, both are brought into surface contact and the flow of magnetic flux is facilitated. However, since the auxiliary pole is formed by forging, it is difficult to make the outer peripheral shape of the auxiliary pole into a curved shape in conformity with the inner peripheral surface of the yoke. Arise.

  An object of the present invention is to improve the contact state between an auxiliary pole and an inner peripheral surface of a yoke in an electric motor with an auxiliary pole without impairing workability and assemblability, and to ensure the effect of installing the auxiliary pole.

  An electric motor of the present invention is an electric motor having a plurality of magnets attached to an inner peripheral surface of a yoke and a metal auxiliary pole arranged adjacent to the magnet, wherein the auxiliary pole is magnetic It is formed by stacking a plurality of metal plates formed by a body, and is arranged in the yoke so that corners of the metal plates are in contact with the inner peripheral surface of the yoke.

  In the present invention, the auxiliary pole formed by stacking the metal plates is attached to the yoke inner peripheral surface so that the corners of each metal plate are in contact with the yoke inner peripheral surface. Contact with multiple points. For this reason, in the electric motor, the contact point between the yoke and the auxiliary pole is increased as compared with the conventional motor with the auxiliary pole, and the flow of the magnetic flux between both is facilitated, and the magnetic flux flowing into the auxiliary pole is increased. The reluctance torque by the auxiliary pole can be easily obtained.

  An engine starter according to the present invention is an engine starter that uses an electric motor as a drive source and meshes a pinion that is rotationally driven by the electric motor with an engine ring gear to start the engine. A plurality of magnets attached to the inner peripheral surface of the yoke, a metal auxiliary pole disposed adjacent to the magnet, and an armature rotatably disposed inside the magnet. The pole is formed by laminating a plurality of metal plates made of a magnetic material, and is arranged in the yoke so that corners of the metal plates are in contact with the inner peripheral surface of the yoke. To do.

  In the present invention, in the electric motor used as the drive source, the auxiliary pole formed by stacking the metal plates is arranged on the yoke inner peripheral surface so that the corners of the metal plates are in contact with the yoke inner peripheral surface. As a result, the auxiliary pole comes into contact with the inner peripheral surface of the yoke at multiple points. For this reason, in the electric motor, the contact point between the yoke and the auxiliary pole is increased as compared with the conventional motor with the auxiliary pole, and the flow of the magnetic flux between both is facilitated, and the magnetic flux flowing into the auxiliary pole is increased. The reluctance torque by the auxiliary pole can be easily obtained.

  According to the electric motor of the present invention, the auxiliary pole attached to the inner peripheral surface of the yoke is formed by laminating a plurality of metal plates made of a magnetic material, and the corners of each metal plate are formed on the inner peripheral surface of the yoke. Since they are arranged in the yoke so as to be in contact with each other, when the auxiliary pole is attached to the inner peripheral surface of the yoke, the auxiliary pole and the yoke can be brought into contact at multiple points. For this reason, compared with the conventional motor with an auxiliary pole, the flow of the magnetic flux between the yoke and the auxiliary pole is facilitated, the magnetic flux flowing into the auxiliary pole is increased, and the reluctance torque by the auxiliary pole is easily obtained. Further, since the auxiliary electrode itself can be easily formed in a symmetrical shape, there is no assembly error, and the auxiliary electrode can be easily processed and manufactured. Therefore, it is possible to increase the contact area between the auxiliary electrode and the inner peripheral surface of the yoke without impairing workability and assembly.

  Further, according to the engine starter of the present invention, the auxiliary pole attached to the inner peripheral surface of the yoke of the electric motor used as the drive source is formed by laminating a plurality of metal plates made of a magnetic material, Since the corners of each metal plate are arranged in the yoke so that they contact the inner peripheral surface of the yoke, when the auxiliary pole is attached to the inner peripheral surface of the yoke, the auxiliary electrode and the yoke can be contacted at multiple points. Become. For this reason, compared with the conventional motor with an auxiliary pole, the flow of the magnetic flux between the yoke and the auxiliary pole is facilitated, the magnetic flux flowing into the auxiliary pole is increased, and the reluctance torque by the auxiliary pole is easily obtained. Further, since the auxiliary electrode itself can be easily formed in a symmetrical shape, there is no assembly error, and the auxiliary electrode can be easily processed and manufactured. Therefore, it is possible to increase the contact area between the auxiliary electrode and the inner peripheral surface of the yoke without impairing workability and assembly.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of an engine starter using an electric motor as a drive source according to an embodiment of the present invention, in which the upper side from the center line shows a stationary state and the lower side shows an energized state. . An engine starter (starter) 1 shown in FIG. 1 is used for starting an automobile engine, and uses a magnet field electric motor (hereinafter abbreviated as a motor) 2 as a drive source.

  The motor 2 is connected to a reduction gear 3, and the rotation of the motor 2 is transmitted to the drive shaft 4 via the reduction gear 3. An overrunning clutch 5 and a pinion gear 6 are provided on the drive shaft (output shaft) 4 so as to be movable in the axial direction. The engine starter 1 is a single-axis type starter in which a magnet switch 7 is arranged coaxially with the drive shaft 4, and the pinion gear 6 is axially moved together with the overrunning clutch 5 by the action of the magnet switch 7. It moves and meshes with the ring gear 8 of the engine.

  The motor 2 has a configuration in which an armature 22 is rotatably disposed in a cylindrical motor housing 21. The motor housing 21 also serves as the yoke of the motor 2 and is made of a magnetic metal such as iron. A metal end cover 23 is attached to the right end portion of the motor housing 21. On the other hand, the left end portion of the motor housing 21 is attached to a gear cover 24 in which the pinion gear 6 is accommodated. The end cover 23 is fixed to the gear cover 24 by a set bolt 25, and the motor housing 21 is fixed between the end cover 23 and the gear cover 24. A plurality (six here) of magnets 26 and auxiliary poles 87 are fixed on the inner peripheral surface of the motor housing 21 at equal pitches (here, 60 ° intervals). An armature 22 is disposed inside the magnet 26. The armature 22 includes an armature core 28 fixed to the motor shaft 27 and an armature coil 29 wound around the armature core 28.

  2 is an explanatory view showing the configuration of the magnet 26 and the auxiliary pole 87, FIG. 3 is an explanatory view showing the configuration of the auxiliary pole 87, and FIG. 4 is an enlarged view of a portion A in FIG. As shown in FIG. 2, the motor 2 has a 6-pole / 26-slot configuration, and the auxiliary pole 87 is installed on the magnetizing side of the magnet 26. As shown in FIG. 3, the auxiliary electrode 87 has a structure in which a plurality of (here, 16) metal plates 88 are laminated, and the metal plates 88 are bonded and fixed to each other. The metal plate 88 is an iron piece formed of a magnetic steel plate such as silicon steel, and has a thickness of about 0.5 mm to 1.0 mm.

  As shown in FIG. 4, the auxiliary pole 87 is attached in the motor housing 21 so that the corners 88 a of the metal plates 88 are in contact with the inner peripheral surface 21 a of the motor housing. Thereby, when the auxiliary pole 87 is attached to the motor housing 21, the auxiliary pole 87 comes into contact with the inner peripheral surface 21a of the motor housing 21 at multiple points. For this reason, in the motor 2, compared with the motor with an auxiliary pole of FIG. 5, the contact point of the motor housing 21 and the auxiliary pole 87 increases, and the flow of the magnetic flux between both becomes easy. As a result, the magnetic flux flowing into the auxiliary pole 87 increases and it becomes easy to obtain reluctance torque by the auxiliary pole.

  Further, since the auxiliary electrode 87 has a symmetrical shape, no assembly error occurs, and the auxiliary electrode can be easily processed and manufactured. Therefore, in the motor 2 of the present invention, the contact area between the auxiliary pole 87 and the motor housing (yoke) inner peripheral surface 21a can be increased without impairing workability and assembling performance. A performance improvement effect can be obtained with certainty.

  On the other hand, the right end portion of the motor shaft 27 is rotatably supported by a metal bearing 31 attached to the end cover 23. On the other hand, the left end portion of the motor shaft 27 is rotatably supported by the end portion of the drive shaft 4 to which the pinion gear 6 and the like are attached. A bearing portion 32 is recessed at the right end portion of the drive shaft 4, and the motor shaft 27 is rotatably supported by a metal bearing 33 attached thereto. As a result, the drive shaft 4 is arranged coaxially with the motor shaft 27 of the motor 2.

  A commutator 34 that is externally fitted and fixed to the motor shaft 27 is disposed adjacent to one end side of the armature core 28. A plurality of commutator pieces 35 formed of a conductive material are attached to the outer peripheral surface of the commutator 34, and the end of the armature coil 29 is fixed to each commutator piece 35. A brush holder 36 is attached to the left end portion of the motor housing 21. In the brush holder 36, a plurality of brush accommodating portions 37 are arranged at intervals in the circumferential direction. Each brush accommodating portion 37 is internally provided with a brush 38 that can be moved in and out. The protruding tip end (inner diameter side tip) of the brush 38 is in sliding contact with the outer peripheral surface of the commutator 34.

  A pigtail (not shown) is attached to the rear end side of the brush 38 and is electrically connected to the first plate 41 a of the conductive plate 41 provided in the brush holder 36. The conductive plate 41 includes the first plate 41a and a second plate 41b that is electrically connected to the power terminal 44. The insulating portion 41c that insulates the plates 41a and 41b from each other. (Hereinafter, the first and second plates 41a and 41b are abbreviated as the plate 41a and the plate 41b, respectively). A switch plate 43 is disposed opposite to the insulating portion 41 c, and a switch portion 42 is formed by both electrical contacts of the conductive plate 41 (plates 41 a and 41 b) and the switch plate 43.

  The switch plate 43 is attached to the switch shaft 45, and when the ignition switch of the engine is turned on and the magnet switch 7 is energized, the switch shaft 45 moves to the left. When the switch plate 43 comes into contact with the plates 41a and 41b, the insulating portion 41c is conducted and the switch portion 42 is turned on. As a result, the power terminal 44 to which the power supply cable (not shown) is attached is electrically connected to the brush 38, and power is supplied from the battery to the commutator 34. On the other hand, when the ignition switch is OFF, the insulating portion 41c is opened and the switch portion 42 is turned OFF, a gap is formed between the conductive plate 41 and the switch plate 43, and power supply to the motor 2 is stopped. To do.

  The planetary gear mechanism 11 of the reduction gear 3 is provided with an internal gear unit 46 and a drive plate unit 47. The internal gear unit 46 is fixed to the right end portion of the gear cover 24, and an internal ring gear 48 is formed on the inner peripheral side thereof. A metal bearing 49 is housed in the center of the internal gear unit 46, and the right end side of the drive shaft 4 is rotatably supported. The drive plate unit 47 is fixed to the right end of the drive shaft 4, and planetary gears 51 are attached at equal intervals. The planetary gear 51 is rotatably supported by a support pin 53 fixed to the base plate 52 via a metal bearing 54. The planetary gear 51 meshes with the internal ring gear 48.

  A sun gear 55 is formed at the left end of the motor shaft 27. The sun gear 55 meshes with the planetary gear 51, and the planetary gear 51 revolves between the sun gear 55 and the internal ring gear 48 while rotating. When the motor 2 operates, the sun gear 55 rotates together with the motor shaft 27, and the planetary gear 51 revolves around the sun gear 55 while meshing with the internal ring gear 48 as the sun gear 55 rotates. As a result, the base plate 52 fixed to the drive shaft 4 rotates, and the rotation of the motor shaft 27 is decelerated and transmitted to the drive shaft 4.

  The overrunning clutch 5 transmits the rotation decelerated by the planetary gear mechanism 11 to the pinion gear 6 in one rotation direction. The overrunning clutch 5 has a configuration in which a roller 58 and a clutch spring (not shown) are arranged between a clutch outer 56 and a clutch inner 57. The clutch outer 56 includes a boss portion 56 a and a clutch portion 56 b, and the boss portion 56 a is attached to the helical spline portion 61 of the drive shaft 4. A spline portion 62 that meshes with the helical spline portion 61 is formed on the inner peripheral side of the boss portion 56a. As a result, the clutch outer 56 can move in the axial direction along the helical spline portion 61 on the drive shaft 4.

  A stopper 63 is attached to the drive shaft 4. The stopper 63 is restricted from moving in the axial direction by a circlip 64 attached to the drive shaft 4. One end of a gear return spring 65 is attached to the stopper 63. The other end side of the gear return spring 65 is in contact with the inner end wall 66 of the boss portion 56a. The clutch outer 56 is urged to the right by the gear return spring 65, and the clutch outer 56 is held at a position in contact with a clutch stopper 67 fixed to the gear cover 24 during normal operation (when power is not supplied). Is done.

  A clutch inner 57 formed integrally with the pinion gear 6 is disposed on the inner periphery of the clutch portion 56 b of the clutch outer 56. A plurality of sets of rollers 58 and clutch springs are disposed between the clutch outer 56 and the clutch inner 57. A clutch cover 68 is externally provided on the outer periphery of the clutch portion 56 b, and a clutch washer 69 is attached between the left end surface of the clutch portion 56 b and the clutch cover 68. By this clutch washer 69, the roller 58 and the clutch spring are accommodated on the inner peripheral side of the clutch portion 56b in a state where movement in the axial direction is restricted.

  The inner peripheral wall of the clutch portion 56b is a cam surface, and a wedge-shaped slope portion and a curved surface portion are formed. The roller 58 is normally pushed to the curved surface side by a clutch spring. When the clutch outer 56 rotates and the roller 58 is sandwiched between the wedge-shaped inclined surface and the outer peripheral surface of the clutch inner 57 against the urging force of the clutch spring, the clutch inner 57 is connected to the clutch outer via the roller 58. Rotate integrally with 56. As a result, when the motor 2 operates and the drive shaft 4 rotates, the rotation is transmitted from the clutch outer 56 to the clutch inner 57 via the roller 58, and the pinion gear 6 rotates.

  On the other hand, when the engine is started and the clutch inner 57 rotates faster than the clutch outer 56, the roller 58 moves to the curved surface side, and the clutch inner 57 is idled with respect to the clutch outer 56. That is, when the clutch inner 57 is in an overrun state, the roller 58 is not sandwiched between the wedge-shaped slope and the outer peripheral surface of the clutch inner, and the rotation of the clutch inner 57 is not transmitted to the clutch outer 56. Therefore, even if the clutch inner 57 is rotated at a higher rotational speed from the engine side after the engine is started, the rotation is interrupted by the overrunning clutch 5 and is not transmitted to the motor 2 side.

  A pinion gear 6 is integrally formed on the left end side of the clutch inner 57. The pinion gear 6 (clutch inner 57) is a steel member formed by cold forging, and chrome steel (for example, SCr 420H) subjected to carburizing treatment is used. A shaft hole 71 is formed on the inner diameter side of the pinion gear 6, and a pinion gear metal 72 is attached to the shaft hole 71. The pinion gear 6 is rotatably supported by the drive shaft 4 via the pinion gear metal 72. On the other hand, a spring accommodating portion 73 is formed on the inner diameter side of the clutch inner 57, and a stopper 63 and a gear return spring 65 are accommodated therein.

  The magnet switch 7 is arranged coaxially with the drive shaft 4 on the left side of the planetary gear mechanism 11 and is concentric with the motor 2 and the planetary gear mechanism 11. The magnet switch 7 includes a steel fixed portion 74 fixed to the gear cover 24 and a movable portion 75 that is movable in the left-right direction along the bobbin 78, that is, is movable relative to the bobbin 78. The fixed portion 74 is provided with a case 76 fixed to the gear cover 24, a coil 77 accommodated in the case 76, and a bobbin 78 attached to the inner peripheral side of the case 76. The coil 77 is electrically connected to an ignition switch (not shown). The movable portion 75 is provided with a movable iron core 79 to which the switch shaft 45 is attached. A gear plunger 81 is attached to the inner peripheral side of the movable iron core 79. A switch return spring 86 is attached to the outer peripheral side (lower end side in the figure) of the movable iron core 79. The other end side of the switch return spring 86 is in contact with the gear cover 24, and the movable iron core 79 is urged to the right.

  A bracket plate 82 is further fixed to the inner periphery of the movable iron core 79. One end of a plunger spring 83 is fixed to the bracket plate 82 by caulking. The other end of the plunger spring 83 is in contact with the gear plunger 81 when the ignition key switch is OFF (in the upper half state of FIG. 1). The gear plunger 81 is attached to the left by the plunger spring 83. It is energized. The gear plunger 81 is attached to the drive shaft 4 so as to be movable in the axial direction, and a sliding iron core 84 is interposed between the inner peripheral surface of the movable iron core 79.

  The gear cover 24 is formed by aluminum die casting, and the left end side of the drive shaft 4 is rotatably supported by a left end portion of the gear cover 24 via a metal bearing 85. A clutch stopper 67 made of a synthetic resin (for example, glass fiber reinforced polyamide), a case 76 and the like are fixed in the gear cover 24. Further, a motor housing 21 and an end cover 23 are fixed to the right end surface side of the gear cover 24 by a set bolt 25.

  Next, the engine starting operation using such an engine starting device 1 will be described. First, when the ignition key switch of the automobile is OFF, the clutch outer 56 is in contact with the clutch stopper 67 by the biasing force of the gear return spring 65 as shown in the upper half of FIG. At this time, the switch plate 43 is separated from the conductive plate 41, and power supply to the motor 2 is not performed. Further, the pinion gear 6 is in the right disengagement position and is not engaged with the ring gear 8.

  On the other hand, when the ignition key switch is turned on, first, a current flows through the coil 77 and an attractive force is generated in the magnet switch 7. When the coil 77 is excited, a magnetic path passing through the case 76 and the bobbin 78 is formed, and the movable iron core 79 is attracted to the left. When the movable iron core 79 is sucked to the left, the bracket plate 82 moves to the left, and the plunger spring 83 is compressed. The repulsive force of the plunger spring 83 at this time is set to be larger than the repulsive force of the gear return spring 65, and the gear plunger 81 is moved to the left by the suction force applied to the sliding iron core 84 and the plunger spring 83. Pressed. As a result, the clutch outer 56 moves on the helical spline portion 61 along the axial direction, and the pinion gear 6 also moves leftward.

  On the other hand, when the movable iron core 79 moves to the left against the urging force of the switch return spring 86, the switch shaft 45 also moves to the left, the switch plate 43 contacts the conductive plate 41, and the contact is closed. As a result, the power supply terminal 44 and the brush 38 are electrically connected, power is supplied to the commutator 34, the motor 2 operates, and the armature 22 rotates. When the motor 2 operates and the armature 22 rotates, the drive shaft 4 rotates through the planetary gear mechanism 11.

  As the drive shaft 4 rotates, the clutch outer 56 attached to the helical spline portion 61 also rotates. The helical spline portion 61 has a twisting direction set in consideration of the rotational direction of the drive shaft 4. When the rotational speed of the clutch outer 56 increases, the inertial mass causes the clutch outer 56 to move along the helical spline portion 61. Move to the left. When the clutch outer 56 jumps to the left as the motor 2 rotates, the pinion gear 6 moves to the left together with the clutch outer 56, and the pinion gear 6 meshes with the ring gear 8. That is, with the ignition key switch ON, the pinion gear 6 is first pushed to the left by the gear plunger 81, and then pops out to the left at a stroke with the operation of the motor 2 to mesh with the ring gear 8.

  As a result, the pinion gear 6 moves to the operating position as shown in the lower half of FIG. 1, the rotation of the motor 2 is transmitted to the ring gear 8, and the ring gear 8 rotates. The ring gear 8 is connected to the crankshaft of the engine. As the ring gear 8 rotates, the crankshaft rotates and the engine is started. When the engine is started, the pinion gear 6 is rotated at a high speed by the ring gear 8, but the rotation is not transmitted to the motor 2 side due to the action of the overrunning clutch 5.

  When the clutch outer 56 moves leftward, the gear return spring 65 is also pushed by the clutch outer 56 and contracted. Further, the plunger spring 83 pushes the gear plunger 81 to the left, and is released when the pinion gear 6 and the ring gear 8 are completely engaged with each other, so that a natural length state is obtained. Therefore, a slight gap is generated between the gear plunger 81 and the plunger spring 83 in contact with the clutch outer 56 as in the lower half state of FIG.

  When the engine is started, the pinion gear 6 is rotated at a high speed, and the overrunning clutch 5 is rotated in the idling direction. When the overrunning clutch 5 is rotated in the idling direction, idling torque is generated in the clutch, and a rotational force called cutting torque acts on the clutch outer 56. Due to this rotational force, a rightward thrust force is generated in the clutch outer 56 via the helical spline portion 61, and the clutch outer 56 may move to the right and the pinion gear 6 may be disengaged from the ring gear 8. Therefore, in the engine starting device 1, the gear plunger 81 is held at the moving left end position (see the lower half of FIG. 1) by the electromagnetic attractive force applied to the sliding iron core 84, and the movement of the clutch outer 56 is restricted. Thereby, the rightward movement of the pinion gear 6 is restricted, and the detachment of the pinion gear 6 is suppressed.

  On the other hand, when the engine is started and the ignition key switch is turned off, the energization to the magnet switch 7 is stopped and the attractive force disappears. Then, the bracket plate 82 is pushed rightward by the urging force of the switch return spring 86, and the movable iron core 79 that has been held leftward by the suction force by the bobbin 78 is moved rightward. When the movable iron core 79 moves to the right, the switch shaft 45 also moves to the right, the switch plate 43 is separated from the conductive plate 41, and the contact is opened. Thereby, the power supply to the motor 2 is interrupted, the rotation of the drive shaft 4 is stopped, and the rotation of the clutch outer 56 is also stopped.

  When the rotation of the clutch outer 56 stops, the moving force in the axial direction due to the inertia mass disappears. For this reason, the clutch outer 56 moves to the right from the operating position to the stationary position along the helical spline portion 61 by the biasing force of the gear return spring 65 that has been compressed. At this time, the gear plunger 81 is also pushed by the clutch outer 56 to be in the upper half of FIG. The urging force of the gear return spring 65 is set to be larger than the urging force of the plunger spring 83 at this time. When the clutch outer 56 moves to the right, the pinion gear 6 also moves to the right, disengages from the ring gear 8, and returns to the upper half state of FIG.

  It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, the motor 2 described above is a motor used as a drive source of the engine starter, but the present invention is not limited to the engine starter motor and can be widely applied to electric motors in general.

It is sectional drawing which shows the structure of the engine starting apparatus which uses the electric motor which is one Example of this invention as a drive source, The upper side from the centerline has shown the stationary state, and the lower side has shown the energized state. It is explanatory drawing which shows the structure of the magnet and auxiliary pole of the electric motor which are used for the engine starting apparatus of FIG. It is explanatory drawing which shows the structure of an auxiliary pole. It is an enlarged view of the A section of FIG. It is explanatory drawing which shows the state of the auxiliary pole of the conventional motor with an auxiliary pole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine starter 2 Electric motor 3 Reduction gear 4 Drive shaft 5 Overrunning clutch 6 Pinion gear 7 Magnet switch 8 Ring gear 11 Planetary gear mechanism 21 Motor housing 21a Inner peripheral surface 22 Armature 23 End cover 24 Gear cover 25 Set bolt 26 Magnet 27 Motor shaft 28 Armature core 29 Armature coil 31 Metal bearing 32 Bearing portion 33 Metal bearing 34 Commutator 35 Commutator piece 36 Brush holder 37 Brush housing portion 38 Brush 41 Conductive plate 41a First plate 41b Second plate 41c Insulating portion 42 Switch portion 43 Switch plate 44 Power terminal 45 Switch shaft 46 Internal gear unit 47 Drive plate unit 48 Internal ring 49 Metal bearing 51 Planetary gear 52 Base plate 53 Support pin 54 Metal bearing 55 Sun gear 56 Clutch outer 56a Boss part 56b Clutch part 57 Clutch inner 58 Roller 61 Helical spline part 62 Spline part 63 Stopper 64 Circlip 65 Gear return spring 66 Inner end wall 67 Clutch stopper 68 Clutch cover 69 Clutch washer 71 Shaft hole 72 Pinion gear metal 73 Spring accommodating portion 74 Fixed portion 75 Movable portion 76 Case 77 Coil 78 Bobbin 79 Movable iron core 81 Gear plunger 82 Bracket plate 83 Plunger spring 84 Sliding iron core 85 Metal bearing 86 Switch return spring 87 Auxiliary pole 88 Metal plate 88a Corner
101 Auxiliary electrode
101a Corner
102 York
102a Yoke inner peripheral surface G Gap

Claims (2)

An electric motor having a plurality of magnets attached to the inner circumferential surface of the yoke and a metal auxiliary pole disposed adjacent to the magnets;
The auxiliary pole is formed by laminating a plurality of metal plates made of a magnetic material, and is arranged in the yoke so that corners of the metal plates are in contact with the inner circumferential surface of the yoke. A featured electric motor. An engine starter that uses an electric motor as a drive source and engages a pinion rotated by the electric motor with an engine ring gear to start the engine,
The electric motor has a plurality of magnets attached to the inner peripheral surface of the yoke, and a metal auxiliary pole disposed adjacent to the magnets,
The auxiliary pole is formed by laminating a plurality of metal plates made of a magnetic material, and is arranged in the yoke so that corners of the metal plates are in contact with the inner circumferential surface of the yoke. A characteristic engine starting device.

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