JP3065247B2 - Starter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starter for starting an engine.

[0002]

2. Description of the Related Art In recent years, a starter for an automobile has been required to be further reduced in size because a spare space in an engine room has been reduced due to an increase in accessory parts accompanying an increase in performance of an engine. Therefore, in order to respond to the demand for downsizing, a deceleration type starter in which a motor, which is a main part of the starter, is reduced in size and rotated at a high speed using a reduction gear has become mainstream.

[0003]

However, if the reduction ratio of the speed reducer is greatly increased from 6 to 10 in comparison with the conventional 4 to 5 in order to realize a further miniaturization, the motor rotation shaft (armature shaft) is required. However, the critical rotation speed and the strength of the commutator due to the deflection in ()) become problems. However, in the conventional starter in which a commutator is arranged at one end of the armature core in the axial direction of the motor rotation shaft, the length of the motor rotation shaft becomes longer, so that the dangerous rotation speed of the motor rotation shaft is greatly increased. Is difficult. It should be noted that the critical rotation speed can be increased by making the motor rotating shaft thicker, but results in conflicting demands for downsizing.

As a commutator, a molded commutator is generally used in which a plurality of commutator pieces (for example, copper pieces) are arranged in a cylindrical or disk shape and molded and fixed with a phenolic thermosetting resin. . Accordingly, since the strength of the commutator is substantially determined by the strength of the phenol resin, there is a problem that it is difficult to greatly improve the strength of the commutator.

On the other hand, when the DC commutator motor is rotated at a high speed, the rectification performance is remarkably reduced due to an increase in the reactance voltage, and it is difficult to ensure the durability of the brush by the generated spark. In order to improve the commutation performance, it is conceivable to provide an auxiliary pole on the fixed magnetic pole.However, in a small commutator motor such as a starter, there is no space for providing the auxiliary pole. No improvement in performance can be expected. Therefore, in order to improve the commutation performance, it is necessary to improve the performance of the brush. As a means therefor, a multi-layer brush in which different types of brush materials of a low resistance layer and a high resistance layer are stacked in the rotation direction of the commutator is known. (JP-A-2-860
No. 81).

However, since the mechanical strength of this multi-layer brush is lower than that of a conventional single-layer brush, if the speed reduction ratio is increased to increase the rotation speed, the vibration caused by the unbalance of the rotating portion increases. However, there arises a problem that strength cannot be tolerated. The present invention has been made based on the above circumstances, and an object of the present invention is to provide a starter which is excellent in durability and can be downsized.

[0007]

The present invention employs the following technical means to achieve the above object. According to the first aspect, since the end of the armature conductor extending radially inward along the end face of the armature core is used as a commutator piece, there is no need to separately provide a commutator. . Therefore, since the armature shaft length (the length of the rotating shaft) can be shortened, the critical rotation speed of the armature shaft can be set higher than that of the conventional starter, and it is possible to cope with a higher rotation speed. Further, since it is not necessary to arrange the commutator pieces forming the commutator in a cylindrical shape or a disk shape and fix them with a mold resin as in the related art, there is a possibility that the strength of the commutator may be insufficient even at a high rotation speed. Absent.

Since the armature shaft length can be shortened as described above, it is possible to suppress the armature vibration generated at the time of high rotation. Thereby, even if a multi-layer brush having lower mechanical strength than a single-layer brush is used, it is possible to cope with sufficiently high rotation. Therefore, it is possible to compensate for the decrease in the rectification performance due to the increase in the reactance voltage when the rotation speed is increased by employing the multilayer brush.

According to the second aspect, since the brush is provided on the end of the armature conductor extending radially inward along the end face of the armature core, it is necessary to separately provide a commutator. In addition, the armature shaft length (the length of the rotating shaft) can be reduced. Therefore, it is possible to set the critical rotation speed of the armature shaft higher than that of the conventional starter, and it is possible to cope with a higher rotation speed. Further, since it is not necessary to arrange the commutator pieces forming the commutator in a cylindrical or disk shape and fix them with the mold resin as in the related art, there is a risk that the commutator may have insufficient strength even at a high rotation speed. Absent. Further, since the length of the armature shaft can be shortened, the vibration of the armature generated at the time of high rotation can be suppressed. Thereby, even if a multi-layer brush having lower mechanical strength than a single-layer brush is used, it is possible to cope with sufficiently high rotation. Therefore, it is possible to compensate for the decrease in the rectification performance due to the increase in the reactance voltage when the rotation speed is increased by employing the multilayer brush.

[0010] According to the third aspect, since the axial length of the armature can be shortened, the interval between the pair of bearings arranged close to the end face of the armature core can be shortened. Thereby, the critical rotation speed of the rotating shaft can be increased without particularly increasing the shaft diameter.

According to a fourth aspect of the present invention, a multi-layer brush is used in which a high resistance brush material is disposed on the armature rotation direction side and a low resistance brush material is disposed on the armature counter rotation direction side. Thereby, the effect of suppressing sparks is improved, and the rectification performance can be improved.

According to the fifth and sixth aspects, the brush shape corresponding to the shape of the commutator piece (the end extending radially inward along the end face of the armature core) according to the number of poles of the starter motor is defined. By adopting, rectification performance can be improved.

According to the seventh aspect of the present invention, the use of the speed reducer for reducing the rotational speed of the armature can reduce the size of the armature and increase the rotation speed. That is, as in the present invention, when the critical rotation speed of the armature shaft can be set higher than that of the conventional starter by shortening the armature shaft, it is possible to cope with higher rotation speed by adopting the reduction gear. it can.

According to the present invention, by setting the speed reduction ratio of the speed reduction device to a large value of 6 or more (conventionally smaller than 6),
The armature can be reduced in size due to high rotation. That is, as described in the first or second aspect, the armature shaft can be shortened to improve durability, and a multilayer brush can be used. Is smaller than 6).

[0015]

Next, an embodiment of a starter according to the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a sectional view of a starter 1. The starter 1 of the present embodiment includes a starter motor 2 that generates a rotational force when energized, an output shaft 3 that rotates by receiving the rotational force of the starter motor 2, a pinion 4 that fits around the outer periphery of the output shaft 3, A torque transmitting means (described later) for transmitting the torque of the starter motor 2 to the output shaft 3;
A rotation restricting member 5 for restricting the rotation of the motor, and a magnet switch 6 disposed behind the starter motor 2 (right side in FIG. 1).
And so on.

(Description of Starter Motor 2) The starter motor 2 includes a yoke 7, a fixed magnetic pole 8, an armature 9 (the armature of the present invention), a brush 10, and the like. The yoke 7 is formed by, for example, press working (deep drawing), has a cylindrical shape that is opened only on the rear end side (the right end side in FIG. 1), and has a housing together with the holder 11 disposed on the rear end side of the yoke 7. 12 and the end cover 13. The front end side of the yoke 7 is provided as a partition plate 7a which is bent toward the radially inner side to partition the starter motor 2 and the rotational force transmitting means. The fixed magnetic pole 8 is composed of, for example, a plurality (for example, 6 poles) of permanent magnets,
To form a magnetic field. The fixed magnetic pole 8 may use a field coil that generates a magnetic force when energized, instead of a permanent magnet.

The armature 9 is composed of a shaft 14 forming a rotary shaft, an armature core 15 provided on the outer periphery of the shaft 14, an armature coil (described below) wound around the armature core 15, and the like. Both ends of the shaft 14 are rotatably supported by the partition plate 7a and the holder 11 via bearings 16 and 17, respectively. Armature core 15
Has a slot for accommodating the armature coil (not shown)
Are formed in the circumferential direction along the axial direction. The armature coil includes a plurality of lower-layer armature conductors 18 (for example, made of copper) accommodated on the inner peripheral side of the slot and a plurality of upper-layer armature conductors 19 (for example, made of copper) accommodated on the outer peripheral side of the slot.

The lower armature conductor 18 has both ends 18 a protruding from the slots bent radially inward along the end face of the armature core 15. However, between both ends 18a of the lower armature conductor 18 and the end face of the armature core 15, for example, a resin ring 20 is interposed to ensure insulation between the two. Upper armature conductor 1
In 9, both end portions 19 a protruding from the slot are bent radially inward along the end face of the armature core 15 from outside the lower armature conductor 18. However, between the end 18a of the lower armature conductor 18 and the end 19a of the upper armature conductor 19, for example, a resin spacer 21 is interposed to ensure insulation between the two.

The lower-layer armature conductor 18 and the upper-layer armature conductor 19 are electrically connected by welding or the like at a predetermined winding pitch at the ends of both ends 18a, 19a bent radially inward. Thus, an armature coil (the armature winding of the present invention) is formed. Further, this armature coil is formed by bending an end portion 19 a of an upper armature conductor 19 bent along one end surface (right side in FIG. 1) of the armature core 15.
Are each configured as a commutator piece. The end 19a of the upper armature conductor 19 forming the commutator piece is
It is fixed in the axial direction by a collar 22 fitted to the shaft 14.

The brush 10 is composed of at least one pair of a positive brush 10A and a negative brush 10B.
3 is pressed against a commutator piece (hereinafter referred to as 19a). However, the positive electrode brush 10A is held by a metal (for example, aluminum) holder 11 via an insulating cylinder 24 made of resin. As shown in FIG. 2, the brush 10 has two types of brush materials 10a and 10a having different resistivity.
A multi-layer brush is used in which b is laminated in the sliding contact direction with the commutator piece 19a (the rotation direction of the armature 9).

Specifically, the resistivity is 600 to 2000 μΩ.
・ Cm high resistance brush material 10a and resistivity of 10-20μ
Ω · cm low-resistance brush material 10 b, and the low-resistance brush material 10
b, and a high-resistance brush material 10a is arranged on the rear side. A spring 23 for urging the brush 10 is held by an end cover 13 attached to the rear end of the holder 11. A terminal bolt 25 to which a battery cable (not shown) is connected is fixed to the end cover 13.

(Explanation of Output Shaft 3) The output shaft 3 is arranged coaxially with the shaft 14 of the armature 9, and its tip is rotatably supported by the housing 12 via a bearing 26, and its rear end is It is rotatably supported by a center case 28 housed inside the housing 12 via a bearing 27. The rear end of the output shaft 3 protrudes outward in the radial direction and is integrally provided as a planet carrier 29 of a planetary gear reduction mechanism (described later). In addition, pinion 4
Helical spline 3a is provided on the outer circumference of the output shaft 3 where
Are formed.

(Description of Pinion 4) The pinion 4 has a pinion helical spline (not shown) formed on the inner peripheral surface thereof, and is fitted with a helical spline 3a formed on the outer periphery of the output shaft 3. By advancing along the helical spline 3a on the shaft 3, it can mesh with a ring gear (not shown) of the engine. This pinion 4 is provided with a spring 30 arranged on the front end side of the pinion 4.
Urges the output shaft 3 rearward. At the rear end of the pinion 4, a rotation regulating plate 31 having an outer diameter larger than that of the pinion 4 is integrally provided. The outer circumferential surface of the rotation restricting plate 31 has an engaging groove 3 extending in the axial direction.
Many 1a are formed at equal intervals in the plate circumferential direction (more than the number of external teeth of the pinion 4).

(Description of Torque Transmission Means) The rotation force transmission means is constituted by a planetary gear reduction mechanism (reduction device of the present invention) and a one-way clutch. 28. The planetary gear reduction mechanism is a reduction gear that increases the output torque of the starter motor 2 by reducing the rotation speed of the armature 9 to a reduction ratio of 6 or more, and a sun gear 32 formed on the outer periphery of the tip of the shaft 14. Three planetary gears 33 meshing with each other, an internal gear 3 meshing with each planetary gear 33
4 and the planet carrier 29 described above.

The sun gear 32 rotates integrally with the shaft 14 to rotate the shaft 14 to three planetary gears 3.
3 Each of the three planetary gears 33 is rotatably supported by a pin 35 fixed to the planet carrier 29 via a bearing 36, and revolves around the outer periphery of the sun gear 32 while meshing with the sun gear 32 and the internal gear 34. Then, the revolving force is transmitted to the planet carrier 29 and the rotational force is transmitted to the output shaft 3. The internal gear 34 is provided in a cylindrical shape, and the outer peripheral surface thereof is slidably in contact with the inner peripheral surface of the cylindrical wall of the center case 28 and is rotatably incorporated.

The one-way clutch supports the internal gear 34 of the planetary gear reduction mechanism so as to be rotatable only in one direction (a direction in which the rotation is performed by receiving the rotation of the engine), and includes a clutch outer 37, a clutch inner 38, and a roller. 39 and a spring (not shown). The clutch outer 37 is provided integrally with the internal gear 34 at the front end side of the internal gear 34. A plurality of wedge-shaped cam chambers (not shown) are formed on the inner peripheral surface of the clutch outer 37 in the circumferential direction.

The clutch inner 38 is connected to the center case 28.
And a cylindrical shape extending in the axial direction at a predetermined interval between the clutch outer 37 and the inner peripheral side of the clutch outer 37. The roller 39 is housed in the cam chamber, and locks the clutch outer 37 and the clutch inner 38 when transmitting the torque of the starter motor 2 to the output shaft 3, and regulates the rotation of the clutch outer 37. The spring is housed in the cam chamber together with the roller 39, and presses the roller 39 toward the narrow side of the cam chamber.

(Explanation of the rotation regulating member 5) The rotation regulating member 5
Is a spring member provided by winding a bar-shaped metal material by about 3/2, and both ends are bent at right angles in the same direction at radially opposed positions. The bent one end 5a
Is a regulating rod that regulates the rotation of the pinion 4 by engaging with an engagement groove 31a formed on the outer peripheral surface of the rotation regulating plate 31 at the initial stage of operation of the starter 1. The other end 5b has
One end of a string member 40 such as a wire is engaged, and the operation of the magnet switch 6 is transmitted through the string member 40.

The rotation restricting member 5 includes a center case 28
It is held movably in the vertical direction (vertical direction in FIG. 1) in a state where the movement in the axial direction (horizontal direction in FIG. 1) is restricted. The rotation restricting member 5 is constantly urged upward by a return spring (not shown), and the operation of the magnet switch 6 is controlled by the other end 5 through the string-shaped member 40.
b, the entire rotation restricting member 5 moves downward against the spring force of the return spring, and when the magnet switch 6 is turned off, is urged upward by the spring force of the return spring to move to the initial position. (The position shown in FIG. 1).

(Explanation of the Magnet Switch 6) The magnet switch 6 is held in the pedestal 41 pressed into the holder 11 and is arranged in the end cover 13, and the shaft 14
Is fixed so that the operation direction (vertical direction in FIG. 1) intersects the operation direction. When a starter switch (not shown) is turned ON to energize a built-in coil (not shown), the magnet switch 6 attracts the plunger 42 housed inside the switch by a magnetic force generated in the coil. As a result, the contacts (not shown) of the motor circuit provided inside the switch are closed to energize the armature 9, and the rotation regulating member 5 is driven via the above-mentioned string-like member 40. As shown in FIG. 1, the string-shaped member 40 is guided by a roller 43 held by the pedestal 41 and a roller 44 held by the center case 28 to transmit the operation of the plunger 42 to the rotation regulating member 5.

Next, the operation of this embodiment will be described. When the starter switch is turned on and the magnet switch 6 is operated, the string member 40 is moved with the movement of the plunger 42.
Is pulled to the magnet switch 6 side,
The rotation restricting member 5 moves downward along the center case 28. As a result, the regulating rod (hereinafter referred to as 5 a) of the rotation regulating member 5 engages with the engagement groove 31 a of the rotation regulating plate 31 to regulate the rotation of the pinion 4.

On the other hand, when the magnet switch 6 is actuated, the contact of the starter motor 2 is closed and the armature 9 is energized, so that a rotational force is generated in the armature 9. As a result, the sun gear 32 rotates together with the shaft 14 to drive the three planetary gears 33 to rotate. At this time, the internal gear 34 meshing with each planetary gear 33 tends to rotate in one direction by receiving the rotational force of each planetary gear 33.

By the operation of the internal gear 34,
The roller 39 accommodated in the cam chamber of the clutch outer 37 is pressed by the spring and moves toward the narrower cam chamber, and engages with the outer peripheral surface of the clutch inner 38. As a result, the rotation of the clutch outer 37 is regulated by being locked by the clutch inner 38 (non-rotatable) formed integrally with the center case 28 via the roller 39. As a result,
Internal gear 34 integral with clutch outer 37
Is restricted, the three planetary gears 33
The outer periphery of the sun gear 32 revolves while rotating around the center 5, and the revolving force is transmitted to the planet carrier 29 to rotate the output shaft 3.

The rotation of the output shaft 3 also causes the pinion 4 to rotate. However, since the rotation of the pinion 4 is regulated by the regulating rod 5a, the rotational force of the output shaft 3 is pushed out in the axial direction with respect to the pinion 4. Acts as thrust.
As a result, the pinion 4 can advance with respect to the output shaft 3 along the helical spline 3a and mesh with the ring gear. When the pinion 4 completely meshes with the ring gear, the tip of the regulating rod 5a is disengaged from the engagement groove 31a of the rotation regulating plate 31 and falls to the rear end side of the rotation regulating plate 31, whereby the rotation regulation of the pinion 4 is released. .
As a result, the rotational force of the output shaft 3 is transmitted to the ring gear meshing with the pinion 4, and the engine can be started by rotating the ring gear.

When the pinion 4 advances and meshes with the ring gear, the urging force of the spring 30 for urging the pinion 4 increases. When the pinion 4 is rotated by the ring gear after the engine is started, the rotational force of the engine acts in a direction to retract the pinion 4 by the action of the helical spline 3a. With these forces,
Although the pinion 4 tends to retreat with respect to the output shaft 3, the retraction of the pinion 4 is prevented by the tip of the regulating rod 5 a that has fallen to the rear end side of the rotation regulating plate 31 supporting the rear end face of the rotation regulating plate 31. Is done.

Thereafter, when the starter switch is turned off and the operation of the magnet switch 6 is stopped, the string-shaped member 4
Since the pulling force of the rotation restricting member 5 through 0 disappears, the rotation restricting member 5 returns to the initial position by the spring force of the return spring. As a result, the regulating rod 5a, which has prevented the pinion 4 from retreating, comes off the rotation restricting plate 31, so that the pinion 4 receiving the urging force of the spring 30 and the retreating force from the ring gear returns to the initial position (the state shown in FIG. 1). Return.

(Effect of Embodiment) Starter 1 of this embodiment
Is formed by bending both end portions 18a, 19a of the lower armature conductor 18 and the upper armature conductor 19 radially inward along the end face of the armature core 15, and forming one end face thereof (the end of the upper armature conductor). ) Are configured as commutator pieces 19a.
For this reason, the entire length of the armature 9 can be significantly reduced as compared with a conventional starter in which a commutator is arranged in the axial direction of an armature core. As a result, the distance between the bearings 16 and 17 that support both ends of the shaft 14 can be reduced, so that the critical rotation speed of the shaft 14 can be increased without increasing the diameter of the shaft.

Further, since the end of the upper armature conductor 19 is used as the commutator piece 19a, the centrifugal strength can be sufficiently increased without being affected by the strength of the molding resin as in the conventional commutator. . As a result, the speed reduction ratio of about 4 to 5 in the conventional speed reduction type starter can be significantly increased to 6 to 10 in this embodiment.
Even at such a high reduction ratio, in addition to the fact that the bearing interval of the shaft 14 can be reduced, the dual bearings 16, 1
7 can reduce the misalignment between the shafts 7.
4 can be kept low. As a result, although the mechanical strength is lower than that of the single-layer brush, it is possible to stably use the multilayer brush 10 having excellent rectification performance, so that the starter motor 2 which is a main part of the starter 1 is much more conventional. The structure can be reduced in size and also excellent in durability.

Further, since the entire length of the armature 9 is reduced, the magnet switch 6 is placed behind the starter motor 2 so that the operation direction (the operation direction of the plunger 42) is substantially perpendicular to the shaft 14 of the armature 9. By arranging, the total length can be shorter than that of the conventional starter. In particular, the magnet switch 6 is connected to the starter motor 2
As compared with the conventional starter provided on the outer peripheral side of the vehicle, the dimension in the radial direction can be greatly reduced, so that the mountability to the engine is greatly improved.

(Second Embodiment) FIG. 3 is a view of the commutator surface and the brush viewed from the axial direction. This embodiment is an example in which the number of poles of the starter motor 2 is two, and the shapes of the high-resistance brush material 10a and the low-resistance brush material 10b forming the multilayer brush 10 are different from those of the first embodiment. That is, since the shape of the commutator piece 19a differs according to the number of poles of the starter motor 2, the shapes of the high-resistance brush material 10a and the low-resistance brush material 10b stacked in the sliding contact direction with the commutator piece 19a are also As shown in FIG. 3, the shape is different from that of the first embodiment.

(Modification) In both the first and second embodiments, the high-resistance brush material 10a and the low-resistance brush material 10b are used.
Although a brush having a layered structure is illustrated, the brush is not limited to two layers, and brushes having different resistivity may be laminated in three or more layers. The end of the upper armature conductor 19 bent along one end face of the armature core 15 is connected to a commutator piece 19a.
The brush 10 is also arranged on the other side of the armature 9, and the end of the upper armature conductor 19 bent along the other end face of the armature core 15 is connected to the commutator piece 1.
9a is also possible.

In the above embodiment, the lower armature conductor 18 and both ends 18a, and the upper armature conductor 1
Although 9 and both ends 19a are formed integrally, they may be electrically connected by separate members. In addition, if the upper armature conductor 19 is configured such that one end portion bent along one end surface of the armature core 15 is a commutator piece 19a, the other end on the other end surface side of the armature core 15 is provided. The portion may not be formed along the end face of the armature core 15.

[Brief description of the drawings]

FIG. 1 is a sectional view of a starter.

FIG. 2 is a diagram of a commutator surface and a brush viewed from an axial direction.

FIG. 3 is a diagram showing a commutator surface and a brush viewed from an axial direction (second embodiment).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Starter 3 Output shaft 4 Pinion 6 Magnet switch 7 Yoke 8 Fixed magnetic pole (field pole) 9 Armature (armature) 10 Brush 10a High resistance brush material 10b Low resistance brush material 14 Shaft (rotary shaft of armature) 15 Armature core 16 Bearing 17 Bearing 18 Lower armature conductor (armature conductor) 19 Upper armature conductor (armature conductor) 19a Commutator piece (end of upper armature conductor)

Claims (8)

(57) [Claims] 1. An electric machine comprising a rotating shaft supporting an armature core, a plurality of armature conductors housed in the armature core, and both ends of each armature conductor connected at a predetermined winding pitch. An armature having an armature winding; and a brush for energizing the armature winding, wherein the armature has at least one end of the armature conductor having a diameter along an end surface of the armature core. The brush is a multi-layer brush in which a plurality of different types of brush materials having different resistivity are stacked in the rotating direction of the armature. And starter. 2. A rotating shaft for supporting an armature core, a plurality of armature conductors housed in slots of the armature core, and the armature core electrically connected to both ends of the armature conductor, respectively. An armature having a pair of ends extending radially inward along the end face thereof, and having an armature winding formed by connecting both ends of each armature conductor at a predetermined winding pitch, A yoke provided on an outer peripheral side of the armature and having a plurality of field poles; and a brush slidably provided on an end of the armature conductor and supplying a current to the armature conductor, The starter is characterized in that the brush is a multi-layer brush in which a plurality of different types of brush materials having different resistivities are laminated in the rotation direction of the armature. 3. The starter according to claim 1, further comprising a pair of bearings disposed at both ends of the rotating shaft and close to an end face of the armature core, the bearings rotatably supporting the rotating shaft. Starter characterized by doing. 4. The starter according to claim 1, wherein said brush has a high-resistance brush material on a rotation direction side of said armature and a low-resistance brush material on a non-rotation direction side of said armature. A starter characterized by having a material. 5. The starter according to claim 1, wherein the side of the brush in the rotation direction of the armature is arranged substantially parallel to a side of an end of the armature conductor. A starter characterized in that: 6. The starter according to claim 1, wherein the side of the brush in the rotation direction of the armature is arranged at a predetermined angle to a side of an end of the armature conductor. A starter characterized by being made. 7. The starter according to claim 1, wherein a pinion that meshes with a ring gear of an engine, an output shaft on which the pinion fits, and a rotational speed of the armature are reduced. A speed reducer for transmitting to the output shaft. 8. The starter according to claim 7, wherein a speed reduction ratio of said speed reduction device is 6 or more.