JP2019138250A - Starter - Google Patents

Abstract

To provide a starter capable of suppressing axial vibrations.SOLUTION: A stater (10) giving rotation torque to a ring gear (18) of an engine (17) includes: a stator (30) which has a magnet portion (32); a rotator (20) rotatably supported; a transmission mechanism (40) which transmits the rotation torque; an output shaft (60) which is rotatably supported coaxially with a rotary shaft (23), and to which the rotation torque is transmitted through the transmission mechanism; and a pinion gear (11). In the axial direction, a magnetic center of the magnet portion is disposed on the output shaft side than a magnetic center of a rotator core. Between the output shaft and the rotary shaft, a thrust bearing portion (90) is provided, and during energization to a rotator coil, the output shaft abuts on the rotary shaft in the axial direction through the thrust bearing portion.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a starter that applies rotational torque to a ring gear of an engine.

  2. Description of the Related Art Conventionally, a starter that applies rotational torque to an engine ring gear has been required to suppress noise during starting. Therefore, as shown in Patent Document 1, a starter has been proposed in which the magnetic center of the magnet is offset in the axial direction from the magnetic center of the armature core. Thereby, at the time of start-up, an axial force can be applied to the armature, and the armature can be brought into pressure contact with the end face of the cylindrical slide bearing that rotatably supports the armature shaft. Therefore, at the time of starting, the vibration of the armature in the axial direction can be suppressed and noise can be suppressed.

International Publication No. 2017/154363

  By the way, in the starter of Patent Document 1, a force is applied to the armature on the non-ring gear side (anti-drive shaft (output shaft) side) in the axial direction. Therefore, unlike the armature, the drive shaft to which the pinion gear is fixed has no force applied in the axial direction, and may vibrate and cause noise.

  The present invention has been made in view of the above circumstances, and a main object thereof is to provide a starter capable of suppressing vibration in the axial direction.

  A first means for solving the above problems is a starter for applying a rotational torque to a ring gear of an engine, a stator having a magnet part, a rotor core and a rotor winding arranged to face the magnet part. A rotor having a wire and supported rotatably, a transmission mechanism for transmitting a rotational torque from the rotary shaft of the rotor, and supported rotatably on the same axis as the rotary shaft. An output shaft to which the rotational torque is transmitted, and a pinion gear that is fixed to the output shaft and meshes with the ring gear of the engine, and the magnetic center of the magnet portion is rotated in the axial direction of the rotational shaft. A thrust bearing portion is provided between the output shaft and the rotating shaft, and is disposed on the output shaft side of the magnetic center of the child core. Is in contact in the axial direction through the thrust bearing portion with respect to the rotary shaft.

  According to the above configuration, in the axial direction, the magnetic center of the magnet portion of the stator is disposed closer to the output shaft than the magnetic center of the rotor core. A thrust load (axial load) is applied to the side. During energization, the output shaft is in contact with the rotating shaft in the axial direction via the thrust bearing portion. Therefore, the axial movement of the rotating shaft and the output shaft is restricted by the thrust load. The Accordingly, it is possible to suppress the vibration of the rotating shaft and the output shaft during start-up, that is, during energization, and reduce noise.

  2nd means WHEREIN: The said thrust bearing part is comprised by the spherical rolling element.

  According to the said structure, the thrust bearing part which is a spherical rolling element is contact | abutted by the line contact or the point contact with respect to each end surface of the output shaft and rotating shaft in an axial direction. Therefore, by filling the periphery of the contact portion with the lubricant, it becomes easier to supply the lubricant to the contact portion during rotation, and the friction is reduced compared to the case where the end surfaces of the output shaft and the rotation shaft are in surface contact with each other. Can be reduced. That is, it can have excellent wear resistance. Moreover, since it is a spherical rolling element, there is little friction, rotation is not inhibited, and noise can be suppressed.

  In the third means, among the end surfaces of the output shaft in the axial direction, the end surface facing the rotation shaft and the end surface facing the output shaft among the end surfaces of the rotation shaft include the output shaft and the Positioning recesses each having a conical surface that opens in the axial direction centered on the axis of the rotating shaft are provided, and the thrust bearing portion is in contact with the conical surface of each positioning recess in the axial direction. Touch.

  According to the said structure, the rolling element which is a thrust bearing part contact | abuts to the conical surface opened to an axial direction centering on an axial center. Thereby, when a rolling element is inserted | pinched with the output shaft and the rotating shaft in the axial direction, the center of a rolling element can be made to correspond with an axial center. For this reason, it can suppress that an output shaft or a rotating shaft inclines or an axial shift arises with respect to a rotation direction. Accordingly, the precession of the output shaft and the rotor can be suppressed to prevent noise.

  In a fourth means, a first thrust bearing portion, which is a thrust bearing portion provided between the rotating shaft and the output shaft, includes a housing that accommodates the output shaft and rotatably supports the output shaft. Separately, a second thrust bearing portion is provided between an end surface of the output shaft in the axial direction opposite to the rotation shaft and an inner surface of the housing facing the end surface of the output shaft. The second thrust bearing portion is constituted by a spherical rolling element, and the output shaft is connected to the housing when the rotor winding is energized. It abuts in the axial direction via a thrust bearing.

  According to the above configuration, the output shaft is in contact with the housing in the axial direction via the second thrust bearing portion when the rotor winding is energized. For this reason, when a thrust load is received from the rotating shaft via the first thrust bearing portion, the output shaft comes into contact with the housing via the second thrust bearing portion and movement in the axial direction is restricted. Become. Thereby, at the time of start-up, that is, at the time of energization, it is possible to suppress the rotation shaft and the output shaft from vibrating in the axial direction and to reduce noise.

  The thrust load from the output shaft to the housing is transmitted by the second thrust bearing portion that is a spherical rolling element. At that time, the second thrust bearing portion comes into contact with each surface of the output shaft and the housing in the axial direction by line contact or point contact. Therefore, by filling the periphery of the contact portion with the lubricant, it becomes easy to supply the lubricant to the contact portion during rotation. For this reason, compared with the case of surface contact, friction can be reduced and it can have the outstanding abrasion resistance. Moreover, since the 2nd thrust bearing part is a spherical rolling element, there is little friction, rotation is not inhibited, and noise can be suppressed.

  5th means WHEREIN: The conical surface opened in the said axial direction centering on the axial center of the said output shaft is made into the surface which faces the said output shaft in the said housing, and the end surface which faces the said housing in the said output shaft. Each of the second thrust bearing portions abuts against the conical surface of each of the positioning recesses provided in the output shaft and the housing, respectively, in the axial direction.

  According to the above configuration, the spherical second thrust bearing portion is in contact with the conical surface opening in the axial direction with the shaft center of the output shaft as the center. Thereby, the center of the 2nd thrust bearing part can be made to correspond with the axis of an output shaft. For this reason, it can suppress that an output shaft inclines with respect to a rotation direction. Accordingly, the precession of the output shaft can be suppressed and noise can be prevented.

  In the sixth means, in the axial direction, the magnetic pole center of the magnet portion is arranged closer to the output shaft side than the center of the rotor core, so that the magnetic center of the magnet portion is the rotor. It is arranged closer to the output shaft than the magnetic center of the core.

  In the above configuration, a thrust load can be easily generated by shifting the center of the magnetic pole of the magnet portion.

  7th means WHEREIN: The said magnet part is comprised with the permanent magnet, and the position where magnetic flux density is the highest among the magnetic flux densities from the said permanent magnet in the said axial direction is the magnetic flux density from the said rotor core. The permanent magnet is magnetized by biasing the magnetic field distribution so that it is closer to the output shaft than the position with the highest magnetic flux density.

  By magnetizing the permanent magnet as described above, the center of the magnetic pole of the magnet portion can coincide with the center of the rotor core. For this reason, it can suppress that the axial length of a starter becomes long.

  8th means WHEREIN: The said magnet part is an electromagnet which has a field winding, The position where magnetic flux density is the highest among the magnetic flux densities from the said electromagnet in the said axial direction is the magnetic flux density from the said rotor core. The field windings of the electromagnets are asymmetrical so that they are closer to the output shaft than the position with the highest magnetic flux density.

  By configuring the electromagnet to be asymmetric as described above, the center of the magnetic pole of the magnet portion can be matched with the center of the rotor core. For this reason, it can suppress that the axial length of a starter becomes long.

  In the ninth means, in the axial direction, the position where the magnetic flux density is the highest among the magnetic flux densities from the rotor core is on the side opposite to the output shaft than the position where the magnetic flux density is highest among the magnetic flux densities from the magnet section. Thus, the rotor core was asymmetrically configured.

  By configuring the rotor core asymmetrically as described above, the center of the magnetic pole of the magnet portion can be matched with the center of the rotor core. For this reason, it can suppress that the axial length of a starter becomes long.

Schematic which shows an engine starting system. The schematic sectional drawing of a starter. The principal part sectional drawing of a starter. The schematic sectional drawing of the starter of 2nd Embodiment. The schematic sectional drawing of the starter of another example. The principal part sectional drawing of the starter of another example. The schematic sectional drawing of the starter of another example.

(First embodiment)
Hereinafter, embodiments embodying a starter according to the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent portions are denoted by the same reference numerals in the drawings.

  In FIG. 1, a starter 10 is a planetary engine starter, and includes a motor 12 that rotationally drives a pinion 11 as a pinion gear, and a magnet switch 13 as an electrically driven actuator that can push out the pinion 11 in the axial direction thereof. And.

  The magnet switch 13 includes an excitation coil (not shown) and a plunger 14 slidably provided on the inner periphery of the excitation coil. For example, when the starter switch 15 is turned on by a user's key operation, the excitation coil is supplied with power from the battery 16 outside the starter 10 to generate magnetic force. When the plunger 14 is attracted by the magnetic force generated by the exciting coil, the movable contact provided on the plunger 14 comes into contact with a set of fixed contacts. As a result, the energization circuit from the battery 16 to the motor 12 is closed, and power is supplied to the motor 12.

  The pinion 11 is disposed at a position where the teeth of the pinion 11 can mesh with the ring gear 18 connected to the output shaft (crankshaft 17a) of the engine 17 as the pinion 11 is pushed out. Specifically, when the magnet switch 13 is not energized, the pinion 11 is in a non-contact state with respect to the ring gear 18 (arranged in a non-connected position). When the starter switch 15 is turned on (closed) in this non-contact state, the plunger 14 is attracted in the axial direction by power supply from the battery 16 to the magnet switch 13. At the same time, the pinion 11 is pushed toward the ring gear 18 by the drive lever 14 a connected to the plunger 14.

  At this time, the tooth part provided on the outer peripheral edge of the pinion 11 is fitted between the tooth part provided on the outer peripheral edge of the ring gear 18, thereby the tooth part of the pinion 11 and the tooth part of the ring gear 18. Meshing occurs. In addition, when the motor 12 is energized in the state where the meshing occurs (connection position), the ring gear 18 is rotated by the pinion 11 and initial rotation is applied to the engine 17 (cranking of the engine 17 is performed). ).

  Note that a return spring (biasing member) (not shown) is connected to the plunger 14. The return spring applies a biasing force to the plunger 14 to move the plunger 14 in the direction opposite to the moving direction by the exciting coil. When cranking is completed, energization to the exciting coil is stopped, and only the urging force by the return spring acts on the plunger 14. As a result, the pinion 11 is returned from the coupling position to the non-coupling position via the drive lever 14a.

  Next, the motor 12 will be described with reference to FIG. The motor 12 is a well-known brushed DC motor, and includes an armature 20 as a rotor, a stator 30, a planetary gear mechanism 40 as a transmission mechanism, a clutch 50, an output shaft 60, a front cover 81, A rear cover 82 and a pinion 11 are provided.

  The armature 20 is an armature core 21 as a rotor core that is an iron core, an armature coil 22 as a rotor winding wound around the armature core 21, an armature shaft 23 that is a rotation axis of the armature 20, and a commutator. And a commutator 24. Hereinafter, the axial direction of the armature shaft 23 is simply referred to as an axial direction, and is indicated by an arrow Y in FIG.

  The armature shaft 23 of the armature 20 is rotatably supported with respect to the rear cover 82 via a first bearing 82 a (radial bearing) provided on the rear cover 82. In the axial direction, an armature core 21 is provided at a substantially central portion of the armature shaft 23, and an armature coil 22 is provided on the armature core 21. Further, a cylindrical commutator 24 is fixed to the armature shaft 23 on the rear cover 82 side of the armature coil 22 in the axial direction.

  The commutator 24 is in pressure contact with the power supply brush 25 fixed to the rear cover 82 in the radial direction, and is slidable with respect to the power supply brush 25 when the armature 20 rotates. The commutator 24 is configured to be able to supply power from the battery 16 via the power supply brush 25. The commutator 24 is connected to the armature coil 22 and is configured to supply the power supplied through the power supply brush 25 to the armature coil 22. When power is supplied to the armature coil 22, magnetic force is generated from the armature core 21.

  The stator 30 includes a cylindrical yoke 31 and a plurality of permanent magnets 32 that are magnet portions fixed to the inner peripheral surface of the yoke 31. The yoke 31 is fixed to the rear cover 82. The stator 30 is disposed to face the armature 20. More specifically, the permanent magnet 32 of the stator 30 is arranged around the armature core 21 so as to face the outer peripheral surface of the armature core 21. An air gap is formed between the permanent magnet 32 and the armature core 21. When a magnetic force is generated from the armature core 21, the armature 20 is configured to rotate with respect to the stator 30.

  The planetary gear mechanism 40 includes a sun gear 41 fixed to the armature shaft 23, a plurality of (three in this embodiment) planetary gears 42 that mesh with the sun gear 41, an internal gear 43 that meshes with the planetary gear 42, and the planetary gear 42. A planetary carrier 44 is provided.

  The sun gear 41 is an external gear, is fixed to the armature shaft 23, and rotates integrally with the armature shaft 23. The internal gear 43 is an annular internal gear arranged concentrically with the rotation center of the sun gear 41 (that is, the axis of the armature shaft 23), and is fixed to the front cover 81.

  The planetary gear 42 is an external gear and is rotatably supported by a rotation shaft 45 provided on the planetary carrier 44 via a second bearing 45a (radial bearing). The planetary gear 42 is capable of rotating around the rotation axis 45 and revolving around the sun gear 41. That is, when the sun gear 41 rotates, the planetary gear 42 rotates (spins) in the opposite direction to the sun gear 41. Since the planetary gear 42 meshes with the fixed internal gear 43, the planetary gear 42 rotates (revolves) around the sun gear 41 in the same direction as the sun gear 41 when rotated in the opposite direction.

  The planetary carrier 44 outputs the revolution movement of the planetary gear 42 via the rotation shaft 45. That is, the planetary carrier 44 rotates around the rotation shaft 45 when the planetary gear 42 revolves. The planetary carrier 44 is provided integrally with an outer 51 of the clutch 50 described later.

  The clutch 50 is a cam type (roller type) one-way clutch, and transmits rotational torque from the outer 51 to the inner 53 via a roller 52 disposed in the cam chamber, while the rotational torque from the inner 53 to the outer 51 is transmitted. Block transmission.

  The output shaft 60 is disposed on the same axis as the armature shaft 23. In the axial direction, the end of the output shaft 60 on the side opposite to the motor is rotatably supported by a drive housing 70 described later via a fourth bearing 61 (radial bearing). Further, an inner 53 of the clutch 50 is provided at the end of the output shaft 60 on the motor side in the axial direction. A male-side helical spline (not shown) that is a helical tooth is provided at the center of the output shaft 60.

  The pinion 11 fixed to the output shaft 60 is an external gear configured in an annular shape, and a female-side helical spline (not shown) that is a spiral groove is provided on the inner periphery thereof. The pinion 11 is fitted to the output shaft 60 via a helical spline, and the rotational torque of the output shaft 60 is transmitted to the pinion 11. Further, when the pinion 11 is pushed out by the drive lever 14a, it is pushed out along the helical spline.

  Further, a stop ring 62 is provided on the output shaft 60 on the side opposite to the motor from the pinion 11. When the pinion 11 is pushed out, the pinion 11 comes into contact with the stop ring 62 after the engagement between the pinion 11 and the ring gear 18 is started. The stop ring 62 abuts on the pinion 11, thereby restricting the movement of the pinion 11 and fixing the position of the pinion 11 to the connection position.

  The pinion 11 and the ring gear 18 are set to a predetermined gear ratio. For this reason, in a state where rotational torque is transmitted from the motor 12 to the ring gear 18, the converted rotational speed obtained by multiplying the rotational speed of the ring gear 18 by the gear ratio becomes equal to the rotational speed of the pinion 11. Therefore, when the rotational speed of the pinion 11 is higher than the converted rotational speed, the clutch 50 is in a transmission state (meshing state) in which rotational torque is transmitted from the motor 12 to the ring gear 18. On the other hand, when the rotational speed of the pinion 11 is lower than the converted rotational speed of the ring gear 18, the clutch 50 enters a disconnected state (disengaged state) that blocks transmission of rotational torque from the ring gear 18 to the motor 12.

  The front cover 81 is formed in a bottomed cylindrical shape that opens toward the motor in the axial direction, and the yoke 31 is fixed from the opening side. The front cover 81 is configured to accommodate the planetary gear mechanism 40 and the clutch 50 therein. A through hole 81 a is formed at the bottom of the front cover 81, and the output shaft 60 is disposed so as to pass through the bottom of the front cover 81 through the through hole 81 a. A third bearing 83 (radial bearing) is provided in the through hole 81a, and the output shaft 60 is rotatably supported by the third bearing 83.

  The rear cover 82 is formed in a bottomed cylindrical shape that opens to the output shaft side in the axial direction, and the yoke 31 is fixed from the opening side. The rear cover 82 is configured to accommodate the power supply brush 25 and the commutator 24 therein.

  The motor 12 configured as described above is fixed to a drive housing (hereinafter simply referred to as a housing 70). The housing 70 is formed in a bottomed cylindrical shape that opens to the motor side. Although not shown, the magnet switch 13 is also fixed to the housing 70. An insertion hole 72 into which the output shaft 60 is inserted via the fourth bearing 61 is provided in the center of the bottom 71 of the housing 70. The housing 70 rotatably supports the output shaft 60 via the fourth bearing 61. That is, both ends of the output shaft 60 are rotatably supported by the third bearing 83 provided on the front cover 81 and the fourth bearing 61 provided on the housing 70. In the housing 70, a part of the side wall is opened in the radial direction, and a part of the ring gear 18 is accommodated in the housing 70 through the opening.

  By the way, at the time of starting, the output shaft 60 and the armature shaft 23 may vibrate in the axial direction. Vibrating in the axial direction can cause noise. Therefore, the present embodiment is configured as follows.

  In the axial direction, the permanent magnet 32 has its magnetic center X1 disposed closer to the output shaft than the magnetic center X2 of the armature core 21. The magnetic center in the axial direction is a position where the magnetic flux density is the highest. Specifically, the center of the magnetic pole of the permanent magnet 32 in the axial direction is disposed closer to the output shaft than the center of the armature core 21 in the axial direction. The permanent magnet 32 is magnetized so that the center of the magnetic pole in the axial direction has the highest magnetic flux density.

  The armature shaft 23 is in contact with the output shaft 60 via a rolling element 90 as a thrust bearing portion in the axial direction. The thrust bearing portion is composed of one spherical rolling element (ball).

  Specifically, as described above, the inner 53 of the clutch 50 is provided at the end of the output shaft 60 on the motor side in the axial direction. The inner 53 is configured in a disc shape that is concentric with the axis of the output shaft 60, and the diameter of the inner 53 is larger than the diameter of the output shaft 60 (more specifically, the diameter on the side opposite to the motor from the inner 53). Is also formed large.

  An insertion hole 54 into which the armature shaft 23 is inserted is formed at the center of the inner 53. The insertion hole 54 opens to the motor side in the axial direction, and the tip of the armature shaft 23 is inserted from the opening. The distal end of the armature shaft 23 is rotatably supported with respect to the output shaft 60 via a fifth bearing 55 that is a radial bearing provided on the opening side of the insertion hole 54. The fifth bearing 55 may be a ball bearing or a slide bearing. As a result, the armature shaft 23 is rotatably supported via the first bearing 82 a provided in the rear cover 82 and the fifth bearing 55 provided in the insertion hole 54.

  On the other hand, a rolling element 90 is disposed at the bottom of the insertion hole 54. The rolling element 90 is disposed so as to be sandwiched between the output shaft 60 and the armature shaft 23 in the axial direction. That is, the rolling element 90 is disposed so as to be sandwiched between the bottom surface of the insertion hole 54 and the distal end surface (end surface on the output shaft side) of the armature shaft 23. Note that, at the bottom of the insertion hole 54, the diameter of the insertion hole 54 is substantially the same as the diameter of the rolling element 90. Further, the rolling element 90 is configured to be able to roll in the insertion hole 54. Further, as shown in FIG. 3, a lubricant 90 a (lubricating oil) such as grease is filled between the output shaft 60 and the armature shaft 23 in the insertion hole 54. That is, the periphery of the rolling element 90 is filled with the lubricant 90a. In the figure, the lubricant 90a is shown by broken line hatching.

  In the output shaft 60, an annular plate washer 91 is provided between the bottom surface (inner surface) of the front cover 81 and the inner 53. The inner diameter of the washer 91 is substantially the same as the outer diameter of the output shaft 60 (more specifically, the outer diameter of the output shaft 60 between the bottom surface of the front cover 81 and the inner 53). On the other hand, the outer diameter of the washer 91 is formed larger than the outer diameter of the third bearing 83 provided on the front cover 81. The washer 91 is formed in a plate shape, and has a sliding surface that slides with respect to the end surface of the third bearing 83 in the axial direction. Similarly, the washer 91 has a sliding surface that slides with respect to the end surface of the inner 53 on the side opposite to the motor in the axial direction.

  FIG. 3 is an enlarged view of a portion surrounded by a broken line in FIG. As shown in FIG. 3, in the armature shaft 23, the end surface on the output shaft side (the end surface facing the output shaft 60) has a conical surface that opens to the output shaft side with the axis of the armature shaft 23 as the center. A recess 23a is provided. Further, in the output shaft 60, a positioning recess 54 a having a conical surface that opens toward the motor centering on the axis of the output shaft 60 is provided on the end surface on the motor side, specifically, the bottom surface of the insertion hole 54. ing.

  When the rolling element 90 is sandwiched between the output shaft 60 and the armature shaft 23, the rolling element 90 comes into contact with the conical surfaces of the positioning recesses 23a and 54a. When abutting, the size of the rolling element 90, the angle of the conical surface, and the like are set so that the rolling element 90 is in line contact with the conical surface. Then, since the armature shaft 23 or the output shaft 60 rotates with respect to the rolling element 90 in order to make line contact, the contact portion (line contact portion) is placed around the rolling element 90 as compared with the case of surface contact. The existing lubricant 90a is easily supplied.

  By being configured as described above, when the armature coil 22 is energized, the magnetic center X2 of the armature core 21 is attracted by magnetic force so as to coincide with the magnetic center X1 of the permanent magnet 32. That is, a thrust load is applied to the armature 20 toward the output shaft in the axial direction.

  When a thrust load is applied to the armature shaft 23, the end face on the output shaft side of the armature shaft 23 comes into contact (pressure contact) with the rolling element 90. That is, a thrust load is applied to the rolling element 90 toward the output shaft side. When the thrust load is applied to the rolling element 90, the rolling element 90 comes into contact (pressure contact) with the end surface of the output shaft 60 on the motor side, that is, the bottom surface of the insertion hole 54. Thus, the output shaft 60 is in contact with the armature shaft 23 in the axial direction via the rolling elements 90 during energization. Then, a thrust load toward the non-motor side is applied to the output shaft 60 in the axial direction.

  When the thrust load is applied to the output shaft 60, the inner 53 provided at the end of the output shaft 60 abuts (presses) in the axial direction with the end surface of the third bearing 83 via the washer 91. It will be. As a result, the axial movement of the output shaft 60 is restricted by the front cover 81. Accordingly, the movement of the rolling elements 90 and the armature shaft 23 is also restricted.

  The washer 91 is configured to be slidable with respect to the end surface of the third bearing 83. Similarly, the washer 91 is configured to be slidable with respect to the end surface of the inner 53. For this reason, even if the output shaft 60 contacts the end surface of the third bearing 83 via the washer 91, the washer 91 does not hinder the rotation of the output shaft 60.

  Further, when a thrust load is applied, the rolling elements 90 are in line contact with the conical surfaces of the positioning recesses 23a and 54a, respectively. Further, the periphery of the contact portion is filled with the lubricant 90a, and the lubricant 90a is more easily supplied to the line contact portion than in the case of surface contact. For this reason, when the armature shaft 23 rotates, friction can be reduced as compared with the case where the end surface of the output shaft 60 and the end surface of the armature shaft 23 are in surface contact. Similarly, when the output shaft 60 rotates, friction can be reduced as compared with the case where the end surface of the output shaft 60 and the end surface of the armature shaft 23 are in surface contact.

  Further, when a thrust load is applied, the rolling element 90 is placed on the armature shaft 23 so that the center of the rolling element 90 and the center of the positioning recess 23a (conical surface), that is, the axis of the armature shaft 23 coincide. Contact (pressure contact). Similarly, when a thrust load is applied, the rolling element 90 is connected to the output shaft 60 so that the center of the rolling element 90 and the center of the positioning recess 54a (conical surface), that is, the axis of the output shaft 60 coincide. Will abut (pressure contact). For this reason, the axis of the output shaft 60, the center of the rolling element 90, and the axis of the armature shaft 23 are likely to be on the same axis. That is, it is possible to prevent the shaft from being displaced in the radial direction and the shaft from being inclined with respect to the rotation direction.

  With the configuration described above, the following effects can be obtained.

  In the axial direction, the magnetic center X <b> 1 of the permanent magnet 32 is disposed closer to the output shaft than the magnetic center X <b> 2 of the armature core 21. For this reason, during energization, the armature 20 is applied with a thrust load (axial load) toward the output shaft in the axial direction. During energization, the output shaft 60 is in contact with the armature shaft 23 via the rolling element 90 in the axial direction. Accordingly, the armature shaft 23 and the output shaft 60 are restricted from moving in the axial direction by the thrust load. As described above, it is possible to suppress the vibration of the armature shaft 23 and the output shaft 60 during start-up, that is, during energization, and reduce noise.

  The rolling element 90 is composed of one sphere, and is sandwiched between the armature shaft 23 and the output shaft 60 in the axial direction. And at the time of electricity supply, the rolling element 90 is contact | abutting by the line contact with each end surface of the armature shaft 23 and the output shaft 60 in an axial direction. Further, the periphery of the contact portion is filled with the lubricant 90a. For this reason, when the armature shaft 23 is rotated, the lubricant 90a is easily supplied to the line contact portion as compared with the case of surface contact. Therefore, compared with the case where the end surfaces of the armature shaft 23 and the output shaft 60 are in surface contact with each other, friction can be reduced and excellent wear resistance can be obtained. Moreover, since it is the rolling element 90, when the armature shaft 23 and the output shaft 60 rotate, there is little friction, rotation is not inhibited, and noise can be suppressed.

  Of the end faces of the output shaft 60 in the axial direction, a positioning recess having a conical surface that opens in the axial direction around the axial center of the output shaft 60 at the end face facing the armature shaft 23, that is, the bottom face of the insertion hole 54. 54a is provided. Of the end faces of the armature shaft 23 in the axial direction, an end face facing the output shaft 60 is provided with a positioning recess 23a having a conical surface opening in the axial direction with the axial center of the armature shaft 23 as the center. . And the rolling element 90 is contact | abutted with respect to the conical surface of each positioning recessed part 23a and 54a in an axial direction, respectively.

  Thus, when the rolling element 90 is sandwiched between the armature shaft 23 and the output shaft 60 in the axial direction, the center of the rolling element 90 is the center of the positioning recesses 23a and 54a, that is, the axis centers of the armature shaft 23 and the output shaft 60. Will match. For this reason, the axial center of the armature shaft 23 and the output shaft 60 can be made to coincide with the rotation direction, and the shaft misalignment and the shaft inclination can be suppressed. Accordingly, the precession of the armature shaft 23 and the output shaft 60 can be suppressed, and noise can be prevented. Furthermore, wear (wear due to precession) of the power supply brush 25, the first bearing 82a, and the fourth bearing 61 can be suppressed.

(Second Embodiment)
In the second embodiment, in addition to the configuration of the first embodiment, a second thrust bearing portion is provided between the output shaft 60 and the housing 70. This will be described in detail below. In the present embodiment, the rolling element 90 provided between the armature shaft 23 and the output shaft 60 is referred to as a first rolling element 90. The first rolling element 90 corresponds to a first thrust bearing portion.

  As shown in FIG. 4, in the second embodiment, the insertion hole 72 provided in the bottom portion of the housing 70 does not penetrate in the axial direction but has a bottom surface.

  A second rolling element 190 is disposed at the bottom of the insertion hole 72 provided in the housing 70. The second rolling element 190 is disposed so as to be sandwiched between the output shaft 60 and the housing 70 in the axial direction. In other words, the second rolling element 190 is provided between the end surface of the output shaft 60 in the axial direction opposite to the armature shaft 23 and the inner surface of the housing facing the end surface of the output shaft 60. ing.

  That is, the second rolling element 190 is disposed so as to be sandwiched between the bottom surface of the insertion hole 72 and the end surface of the output shaft 60 in the axial direction (end surface facing the housing 70). Note that, at the bottom of the insertion hole 72, the diameter of the insertion hole 72 is substantially the same as the diameter of the second rolling element 190. The second rolling element 190 is configured to be able to roll in the insertion hole 72. Further, in the insertion hole 72, the space between the output shaft 60 and the housing 70 is filled with a lubricant 190 a (lubricating oil) such as grease. That is, the periphery of the second rolling element 190 is filled with the lubricant 190a.

  Further, in the housing 70, the surface facing the end surface of the output shaft 60 in the axial direction, specifically, on the bottom surface of the insertion hole 72, the output shaft side is centered on the axis of the output shaft 60 (see FIG. 4). A positioning recess 72a having a conical surface that is open is provided. On the other hand, in the output shaft 60, a positioning recess 60 a having a conical surface that opens to the housing side (see FIG. 4) around the axis of the output shaft 60 is provided on the end surface facing the housing 70.

  When the second rolling element 190 is sandwiched between the output shaft 60 and the housing 70, the second rolling element 190 comes into contact with the conical surfaces of the positioning recesses 60a and 72a. When abutting, the size of the second rolling element 190 and the angle of the conical surface are set so that the second rolling element 190 is in line contact with the conical surface. And since it makes line contact, when the output shaft 60 rotates with respect to the 2nd rolling element 190, compared with the case where surface contact, the contact part (line contact part) of the 2nd rolling element 190 is in contact. The lubricant 190a existing around is easily supplied.

  When the second rolling elements 190 are in contact with the housing 70 and the output shaft 60, respectively, between the end surface of the inner 53 (the end surface on the counter-motor side) and the bottom surface of the front cover 81 in the axial direction. The distance is set to be larger than the thickness of the washer 91.

  By being configured as described above, when the armature coil 22 is energized, the magnetic center X2 of the armature core 21 is attracted by magnetic force so as to coincide with the magnetic center X1 of the permanent magnet 32. That is, a thrust load is applied to the armature 20 toward the output shaft in the axial direction.

  When a thrust load is applied to the armature shaft 23, the distal end surface on the output shaft side of the armature shaft 23 comes into contact (pressure contact) with the first rolling element 90. That is, a thrust load is applied to the first rolling element 90 toward the output shaft side. Then, when a thrust load is applied to the first rolling element 90, the first rolling element 90 comes into contact (pressure contact) with the end surface of the output shaft 60 on the motor side, that is, the bottom surface of the insertion hole 54. It will be. A thrust load on the housing side is applied to the output shaft 60 in the axial direction.

  When the thrust load is applied to the output shaft 60, the end surface on the housing side of the output shaft 60 comes into contact (pressure contact) with the second rolling element 190. Thereby, a thrust load is applied to the second rolling element 190 toward the housing. Then, when a thrust load is applied to the second rolling element 190, the second rolling element 190 comes into contact (pressure contact) with the housing 70. As a result, the output shaft 60 comes into contact (pressure contact) with the housing 70 via the second rolling element 190.

  When the second rolling elements 190 are in contact with the housing 70 and the output shaft 60, as described above, the distance between the end surface of the inner 53 and the bottom surface of the front cover 81 is the washer 91. It is set to be larger than the thickness of. For this reason, the inner 53 does not contact (pressure contact) with the front cover 81 via the washer 91.

  In addition, when a thrust load is applied, the second rolling element 190 is in line contact with the conical surfaces of the positioning recesses 60 a and 72 a in the same manner as the first rolling element 90. Further, the periphery of the contact portion is filled with the lubricant 190a. Therefore, when the output shaft 60 is rotated, the lubricant 190a is more easily supplied to the portion in line contact than in the case of surface contact. For this reason, when the output shaft 60 rotates, friction is reduced as compared with the case where the end face of the inner 53 and the washer 91 are in surface contact.

  When a thrust load is applied, the center of the second rolling element 190 and the centers of the positioning recesses 60a and 23a (conical surfaces), that is, the center of the output shaft 60 are the same as the first rolling element 90. It will contact (pressure contact) so that it may correspond. For this reason, the shaft center of the output shaft 60 and the center of the rolling element 90 are on the same axis, and it is possible to prevent the shaft from being misaligned and tilted with respect to the rotation direction.

  With the configuration described above, the following effects can be obtained.

  The second rolling element 190 is sandwiched between the end surface of the output shaft 60 in the axial direction opposite to the armature shaft 23 and the inner surface of the housing 70 facing the end surface of the output shaft 60. Is provided. The output shaft 60 is in contact with the housing 70 in the axial direction via the second rolling element 190 when energized. For this reason, when a thrust load is received from the armature shaft 23 via the first rolling element 90, the output shaft 60 contacts the housing 70 via the second rolling element 190, and movement in the axial direction is restricted. The Rukoto. Thereby, it is possible to suppress the vibration of the armature shaft 23 and the output shaft 60 during start-up, that is, during energization, and reduce noise.

  The thrust load from the output shaft 60 to the housing 70 is transmitted by the second rolling element 190 configured in a spherical shape. In that case, the 2nd rolling element 190 contact | abuts to the surface of the output shaft 60 and the housing 70 in an axial direction by line contact. Further, the periphery of the contact portion is filled with the lubricant 190a. For this reason, when the output shaft 60 rotates, the lubricant 90a is more easily supplied to the line contact portion than in the case of surface contact. Therefore, as in the first embodiment, compared to the case where the end surface of the inner 53 of the output shaft 60 is in surface contact with the front cover 81 via the washer 91, the friction can be reduced, and the wear resistance is excellent. Can have sex. Further, since the thrust load is transmitted through the spherical second rolling element 190, when the output shaft 60 rotates, there is little friction, the rotation is not hindered, and noise can be suppressed.

  A positioning recess 72 a having a conical surface that opens toward the output shaft in the axial direction is provided on the surface of the housing 70 that faces the output shaft 60 (the bottom surface of the insertion hole 72). Yes. Further, in the output shaft 60, a positioning recess 60 a having a conical surface that opens to the housing side in the axial direction is provided on the end surface facing the housing 70 around the axis of the output shaft 60. The second rolling elements 190 abut against the conical surfaces of the positioning recesses 60a and 72a provided in the output shaft 60 and the housing 70, respectively, when energized. As a result, the center of the second rolling element 190 coincides with the axis of the output shaft 60. Thereby, it is possible to suppress the output shaft 60 from being tilted and the shaft deviation from the rotation direction. Accordingly, precession of the output shaft 60 can be suppressed, noise can be prevented, and further, wear of the third bearing 83 accompanying precession can be suppressed.

(Other embodiments)
In the embodiment described above, the magnetic center of the permanent magnet 32 is arranged closer to the output shaft than the magnetic center of the armature core 21 by shifting the center of the magnetic pole of the permanent magnet 32 and the center of the armature core 21 in the axial direction. However, other configurations may be used. For example, in the axial direction, the magnetic field distribution is such that the position where the magnetic flux density is the highest among the magnetic flux densities from the permanent magnet 32 is closer to the output shaft than the position where the magnetic flux density from the armature core 21 is the highest. You may employ | adopt the permanent magnet 32 (or the permanent magnet 32 magnetized in that way) which has.

  Further, in the axial direction, the armature is arranged such that the position where the magnetic flux density is highest among the magnetic flux densities from the armature core 21 is on the side opposite to the output shaft side from the position where the magnetic flux density is highest among the magnetic flux densities from the permanent magnet 32. What is necessary is just to comprise the core 21 asymmetrically. Specifically, the air gap on the non-output shaft side may be set larger than that on the output shaft side, or a cavity may be provided on the non-output shaft side inside the armature core 21. By configuring as described above, the center of the magnetic pole of the permanent magnet 32 and the center of the armature core 21 can be matched to prevent the starter 10 from being lengthened in the axial direction.

  In the above embodiment, instead of the permanent magnet 32, an electromagnet 300 having a field winding 300a as shown in FIG. In this case, in the axial direction, the position where the magnetic flux density is highest among the magnetic flux densities from the electromagnet 300 is closer to the output shaft than the position where the magnetic flux density is highest among the magnetic flux densities generated from the armature core 21. The electromagnet 300 may be configured asymmetrically in the direction. Specifically, the air gap between the electromagnet 300 on the opposite output shaft side and the armature core 21 is set slightly larger than that on the output shaft side. By configuring as described above, the center of the electromagnet 300 and the center of the armature core 21 can be matched to prevent the starter 10 from being lengthened in the axial direction.

  In the above embodiment, the positioning recesses 23a, 54a, 60a, 72a may not be provided. Alternatively, at least one of the positioning recesses 23a, 54a, 60a, 72a may be provided. When the spherical rolling elements 90 and 190 are brought into contact with either end face, point contact is made. For this reason, even if it is a case where positioning recessed part 23a, 54a, 60a, 72a is not provided, it can have the abrasion resistance outstanding compared with the case where end surfaces are in surface contact.

  In the above embodiment, the spherical rolling elements 90 and 190 are employed as the thrust bearing portion. However, any configuration may be used as long as it can receive a thrust load. For example, a known thrust ball bearing having a plurality of balls may be used, or a known thrust roller bearing having a plurality of rollers (columns) may be used. According to these configurations, when the output shaft 60 or the armature shaft 23 rotates, the rolling element can be rolled (becomes rolling friction), so that the wear resistance can be further improved.

  For example, as shown in FIG. 6, a spherical convex portion 301 may be provided at the tip of the armature shaft 23 (tip on the output shaft side). In this case, the first rolling element 90 can be omitted, and the spherical convex portion 301 becomes a thrust bearing portion (first thrust bearing portion). Similarly, a spherical convex portion may be provided on the end surface of the output shaft 60 (the bottom surface of the insertion hole 54). Also in this case, the first rolling element 90 can be omitted, and the spherical convex portion becomes a thrust bearing portion (first thrust bearing portion).

  Similarly, a spherical convex portion may be provided at the tip of the output shaft 60 (tip on the housing side). In this case, the second rolling element 190 can be omitted, and the spherical convex portion becomes the thrust bearing portion (second thrust bearing portion). Similarly, a spherical convex portion may be provided on the end surface of the housing 70 (the bottom surface of the insertion hole 72). Also in this case, the second rolling element 190 can be omitted, and the spherical convex portion becomes a thrust bearing portion (second thrust bearing portion).

In the above embodiment, a transmission mechanism other than the planetary gear mechanism 40 may be employed as long as the rotational torque from the armature shaft 23 can be transmitted to the output shaft 60.
In the above embodiment, the output shaft 60 may not be provided with the insertion hole 54. In this case, the rolling element 90 may be sandwiched between the end surface of the output shaft 60 and the end surface of the armature shaft 23 in the axial direction.

  In the second embodiment, an accommodation recess for accommodating the second rolling element 190 may be provided at the tip of the output shaft 60. For example, as shown in FIG. 7, an accommodation recess 200 that opens toward the housing and is formed along the axial direction may be provided at the tip of the output shaft 60 that faces the housing 70 in the axial direction. And you may make it accommodate a part of 2nd rolling element 190 in the said accommodation recessed part 200. FIG. By comprising in this way, the axial length of the starter 10 can be suppressed.

In the above embodiment, the planetary gear mechanism 40 and the clutch 50 are provided integrally, but may be provided separately.
In the above embodiment, the positioning recesses 23a, 54a, 60a, 72a have conical surfaces, but the shape of the recesses may be arbitrarily changed. For example, a spherical recess may be provided instead of the conical surface. Even in this case, it is desirable that the centers of the positioning recesses 23 a, 54 a, 60 a, 72 a coincide with the axis of the armature shaft 23 or the output shaft 60.

  DESCRIPTION OF SYMBOLS 10 ... Starter, 11 ... Pinion, 17 ... Engine, 18 ... Ring gear, 20 ... Armature, 21 ... Armature core, 22 ... Armature coil, 23 ... Armature shaft, 30 ... Stator, 32 ... Permanent magnet, 40 ... Planetary gear mechanism 60 ... Output shaft.

Claims (9)

In the starter (10) for applying rotational torque to the ring gear (18) of the engine (17),
A stator (30) having a magnet portion (32);
A rotor (20) having a rotor core (21) and a rotor winding (22) disposed opposite to the magnet portion, and rotatably supported;
A transmission mechanism (40) for transmitting rotational torque from the rotational shaft (23) of the rotor;
An output shaft (60) that is rotatably supported on the same axis as the rotation shaft and to which the rotation torque is transmitted via the transmission mechanism;
A pinion gear (11) fixed to the output shaft and meshing with the ring gear of the engine,
In the axial direction of the rotating shaft, the magnetic center (X1) of the magnet portion is disposed closer to the output shaft than the magnetic center (X2) of the rotor core,
A thrust bearing portion (90) is provided between the output shaft and the rotary shaft, and when the rotor winding is energized, the output shaft is connected to the thrust shaft with respect to the thrust shaft. Starter that is in axial contact with the part.   The starter according to claim 1, wherein the thrust bearing portion is configured by a spherical rolling element. Out of the end surfaces of the output shaft in the axial direction, the end surfaces facing the rotation shaft and the end surfaces of the rotation shaft facing the output shaft are centered on the output shaft and the rotation shaft. Positioning recesses (23a, 54a) each having a conical surface opening in the axial direction in the center are provided,
The starter according to claim 2, wherein the thrust bearing portion abuts against the conical surface of each positioning recess in the axial direction. A housing that houses the output shaft and rotatably supports the output shaft;
Aside from the first thrust bearing portion which is a thrust bearing portion provided between the rotating shaft and the output shaft, an end surface opposite to the rotating shaft among the end surfaces of the output shaft in the axial direction; A second thrust bearing portion is provided between the end surface of the output shaft and the inner surface of the housing facing the output shaft.
The second thrust bearing portion is constituted by a spherical rolling element,
The said output shaft is contact | abutted to the axial direction via the said 2nd thrust bearing part with respect to the said housing at the time of electricity supply to the said rotor coil | winding. The starter described. A positioning recess having a conical surface opening in the axial direction is provided on a surface of the housing facing the output shaft and an end surface of the output shaft facing the housing. And
The starter according to claim 4, wherein the second thrust bearing portion abuts against a conical surface of the positioning recess provided in the output shaft and the housing, respectively, in the axial direction.   In the axial direction, the center of the magnetic pole of the magnet unit is disposed closer to the output shaft than the center of the rotor core, so that the magnetic center of the magnet unit is more than the magnetic center of the rotor core. The starter according to claim 1, which is disposed on the output shaft side. The magnet part is composed of a permanent magnet,
In the axial direction, the magnetic field distribution is such that the position where the magnetic flux density is the highest among the magnetic flux densities from the permanent magnet is on the output shaft side from the position where the magnetic flux density is the highest among the magnetic flux densities from the rotor core. The starter according to any one of claims 1 to 5, wherein the permanent magnet is magnetized while biasing. The magnet part is an electromagnet (300) having a field winding (300a),
In the axial direction, the electromagnet is arranged such that the position where the magnetic flux density is the highest among the magnetic flux densities from the electromagnet is on the output shaft side from the position where the magnetic flux density is the highest among the magnetic flux densities from the rotor core. The starter according to any one of claims 1 to 5, wherein the starter is configured asymmetrically.   In the axial direction, the position where the magnetic flux density is highest among the magnetic flux density from the rotor core is on the side opposite to the output shaft than the position where the magnetic flux density is highest among the magnetic flux density from the magnet part. The starter according to any one of claims 1 to 5, wherein the rotor core is configured asymmetrically.

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