CROSS REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims priority
from Japanese Patent Applications No. 5-332955 filed
December 27, 1993 and No. 6-222321 filed September
19, 1994, with the contents of each document being incorporated
herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention:
This invention relates to a starter for starting an engine
of a motor vehicle according to the preamble of
claim 1.
2. Related Art:
Among conventional starters there are those
wherein the rotation of a motor is transmitted through a
pinion to a ring gear as shown in U.S. Patent No.
1,941,698 or No. 2,342,632. In the former, a starter
wherein by causing a regulating member to abut with
the outer circumferential portion of the pinion, by means
of the rotation of a shaft rotated by a motor, by friction
between the regulating member and the pinion, the pinion
is advanced to the ring gear side and the pinion and
the ring gear are caused to mesh is mentioned. In the
starter of the latter, by causing a pin of a regulating member
to engage with a tooth portion of the pinion, the pinion
is prevented from rotating, the pinion is caused to
advance to the ring gear side, and the pinion and the
ring gear are caused to mesh.
However, when the pinion is caused to mesh with
the ring gear side, when the pinion does not mesh with
the ring gear and the ring gear abuts with the end surface
of the pinion, in conventional starters, although further
rotational force of the motor causes the pinion to
overcome the friction between the regulating member
and the pinion and rotate slightly and the pinion meshes
with the ring gear, because frictional force is used, there
are problems such as setting of the initial frictional force
and that abrasion powder adheres to the sliding surfaces
and consequently the durability is poor.
Also, in the latter conventional technology, when the
ring gear abuts with the end surface of the pinion, there
is the problem that the regulating member suddenly
moving through the pitch of the tooth portion of the pinion
causes an impact between the pinion and the ring
gear, and another constituent member such as a spring
is necessary so that the regulating member passes over
the tooth peaks of the pinion.
US-A-2 332 986 discloses a conventional starter arrangement
comprising an output shaft having an helical
spline, a pinion transmittal member having a pinion for
meshing with a ring gear of an engine and mounted on
the output shaft axially movable through mating with the
helical spline of the output shaft, a motor for rotating the
output shaft thereby to move the pinion toward the ring
gear, and a return preventing member for restricting a
return of the pinion from the ring gear when the pinion
meshes with the ring gear. This arrangement has also
the disadvantage that there arises friction so that abrasion
powder is generated between said pinion and the
return prevention member.
This invention was made in view of the above situation,
and has as an object the provision of a starter of
which the simplicity and durability of the pinion rotation
regulating mechanism is improved.
This object will be solved by the characterising features
of claim 1.
According to a starter of the present invention, when
a pinion regulating means abuts with a pinion and rotation
of an output shaft moves the pinion to a ring gear
side and the pinion abuts with a ring gear, the pinion
regulating means itself bends and allows the pinion to
rotate gradually and mesh with the ring gear and consequentlythere
is no generation of abrasion powder and
a simple constitution with few parts can be adopted.
Further, the pinion is rotatable by at least 1/2 the
pinion gear pitch and it is possible to reliably regulate
the rotation of the pinion.
Further, axial grooves on the pinion moving means
are made more numerous than the pinion gear number,
and the pinion can easily engage with the axial grooves.
The pinion regulating means need only to hold the
pinion with the small force required to regulate the rotation
of the pinion, the pinion regulating means can be
moved to the pinion side by a magnet switch by way of
a cord-shaped member, and the freedom with which the
magnet switch can be disposed can be increased.
Further, the pinion regulating means itself can attain
pinion return prevention when the pinion has meshed
with the ring gear, and the number of parts can be made
small and the assembly can be simplified.
The pinion regulating means itself integrally comprises
urging means for urging the movement to the opposite
side to the pinion, by switching the magnet switch
OFF the pinion regulating means automatically moves
away from the pinion, and the number of parts can be
made small and the assembly can be simplified.
Until the pinion abuts with the ring gear the limiting
means makes the rotation of the output shaft slow and
the pinion is moved to the ring gear side slowly, and it
is not necessary to make the rigidity of the pinion regulating
means itself strong, and it is possible to make the
shock of when the pinion abuts with the ring gear small.
By part of the pinion regulating means having a bar-like
elastic regulating portion, the regulating portion can
reliably bend.
By holding the washer rotatably on the end surface
of the pinion, even when the pinion is over-run by the
ring gear and rotates at high speed, because the washer
is rotatable with respect to the pinion, there is little wear
on the abutting portion of the regulating portion, and the
durability can be increased.
The washer is heat-treated simultaneously with the
pinion, and it is possible to dispense with a process for
making the hardness of the washer above a predetermined
value.
By the movement of the plunger of the magnet
switch, by causing the regulating portion to abut with the
pinion while causing the elastic portion to deform, while
causing the regulating portion to abut with the pinion,
and when the plunger returns, by the elastic force of the
elastic portion, the regulating portion can be reliably
moved away from the pinion.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
Fig. 1 is a sectional side view showing the first embodiment
of a starter of the present invention; Fig. 2 is a perspective view of a pinion rotation regulating
member; Figs. 3A and 3B are a front view and a partial sectional
side view of a pinion rotation regulating member
fitted to a pinion part; Fig. 4 is a rear view of a center bracket; Fig. 5 is a sectional side view of a center bracket; Fig. 6 is a front view of a center bracket; Fig. 7 is a sectional side view of an armature; Fig. 8 is a front view of a yoke; Fig. 9 is an exploded perspective view of a plunger
and contact points of a magnet switch; Fig. 10 is a perspective view showing a plunger of
a magnet switch; Fig. 11 is a sectional view of an end frame and a
brush spring; Fig. 12 is a front view of a brush holder; Fig. 13 is a sectional view taken along the line XIII-XIII
in Fig. 12; Fig. 14 is a sectional view taken along the line XIV-XIV
in Fig. 12. Figs. 15A through 15C are electrical circuit diagrams
in which the operating state of a pinion is
shown; and Fig. 16 is a sectional view of th second embodiment
of the present invention.
DETAILED DESCRIPTION OF THE PRESENTLY
PREFERRED EMBODIMENTS
Next, the starter of this invention will be described
based on the first embodiment shown in Fig. 1 through
Fig. 15.
The starter can be generally divided into a housing
400 containing a pinion 200 which meshes with a ring
gear 100 mounted on an engine (not shown) and a planetary
gear speed reduction mechanism 300, a motor
500, and an end frame 700 containing a magnet switch
600. Inside the starter, the housing 400 and the motor
500 are separated by a motor spacer wall 800, and the
motor 500 and the end frame 700 are separated by a
brush holding member 900.
(Description of the Pinion 200)
As shown in Fig. 1 and further in detail in Figs. 3A
and 3B, a pinion gear 210 which meshes with the ring
gear 100 of the engine is formed on the pinion 200.
A pinion helical spline 211 which mates with a helical
spline 221 formed on an output shaft 220 is formed
around the inner surface of the pinion gear 210.
On the opposite side of the pinion gear 210 from the
ring gear 100 a flange 213 of greater diameter than the
external diameter dimension of the pinion gear 210 is
formed in circular form. A number of projections 214
greater than the number of outer teeth of the pinion gear
210 are formed around the entire outer circumference
of this flange 213. These projections 214 are for a regulating
claw 231 of a pinion rotation regulating member
230 which will be discussed later to mate with. A washer
215 is bent onto the outer peripheral side of an annular
portion 216 formed on the rear end of the pinion gear
210 and thereby disposed rotatably and unable to come
off in the axial direction on the rear surface of the flange
213.
By the rotatable washer 215 being mounted on the
rear surface of the flange 213 of the pinion gear 210 in
this way, when a pinion rotation regulating member 230
which will be discussed later drops in behind the pinion
gear 210, the front end of a regulating claw 231 of the
pinion rotation regulating member 230 abuts with the
washer 215. As a result, the rotation of the pinion gear
210 does not directly abut with the regulating claw 231
of the pinion rotation regulating member 230, and the
washer 215 rotates relatively and the pinion gear 210 is
prevented from being worn by the regulating claw 231
of the pinion rotation regulating member 230.
The pinion gear 210 is urged toward the rear of the
output shaft 220 at all times by a return spring 240 consisting
of a compression coil spring. The return spring
240 not only urges the pinion gear 210 directly but in
this embodiment urges the pinion gear 210 by way of a
ring body 421 of a shutter 420 which opens and closes
an opening portion 410 of the housing 400 and will be
further discussed later.
(Description of the Pinion Rotation Regulating Member
230)
The pinion rotation regulating member 230 constituting
pinion moving means, as shown in Fig. 2 and Figs.
3A and 3B in detail, is a sheet spring member wound
through approximately 3/2 (i.e., 1.5) turns of which approximately
3/4 turns is a rotation regulating portion 232
of long axial sheet length and high spring constant and
the remaining approximately 3/4 turns is a return spring
portion 233 constituting urging means of short axial
sheet length and low spring constant.
A regulating claw 231 which constitutes a regulating
portion extending in the axial direction and which mates
with the multiple projections 214 formed in the flange
213 of the pinion gear 210 is formed at one end of the
rotation regulating portion 232. This regulating claw 231,
as well as mating with the projections 214 of the pinion
gear 210, in order to increase the rigidity of the regulating
claw 231, is formed axially long and is bent radially
inward into a cross-sectional L-shape and is bar-like.
The rotation regulating portion 232 is provided with
a straight portion 235 which extends vertically. This
straight portion 235 is vertically slidably supported by
two supporting arms 361 mounted projecting from the
front surface of a center bracket 360. That is, the straight
portion 235 moving vertically causes the rotation regulating
portion 232 to move vertically also.
Also, a sphere 601 of the front end of a cord-shaped
member 680 (for example a wire), which will be further
discussed later, for transmitting the movement of the
magnet switch 600, which will be further discussed later,
is in engagement with the position 180° opposite the
regulating claw 231 of the rotation regulating portion
232.
The end portion side of the return spring portion 233
has a large curvature of wind and one end portion 236
of the return spring portion 233 abuts with the upper surface
of a regulating shelf 362 mounted projecting from
a front surface of a lower portion of the center bracket
360.
The operation of the pinion rotation regulating member
230 will now be explained. The cord-shaped member
680 is transmitting means for transmitting the movement
of the magnet switch 600 to the regulating claw
231, and the movement of the magnet switch 600 pulls
the rotation regulating portion 232 downward and causes
the regulating claw 231 to engage with the projections
214 on the flange 213 of the pinion gear 210. At
that time, because the end portion 236 of the return
spring portion 233 is in abutment with the regulating
shelf 362 for position regulating, the return spring portion
233 bends. Because the regulating claw 231 is in
engagement with the projections 214 on the pinion gear
210, when the pinion gear 210 starts to be rotated by
way of the armature shaft 510 of the motor 500 and the
planetary gear speed reduction mechanism 300, the
pinion gear 210 advances along the helical spline 221
on the output shaft 220. When the pinion gear 210 abuts
with the ring gear 100 and the advance of the pinion gear
210 is obstructed, further rotational force of the output
shaft 210 causes the pinion rotation regulating member
230 itself to bend and the pinion gear 210 rotates slightly
and meshes with the ring gear 100. When the pinion
gear 210 advances, the regulating claw 231 disengages
from the projections 214, the regulating claw 231 drops
in behind the flange 213 of the pinion gear 210, the front
end of the regulating claw 231 abuts with the rear surface
of the washer 215 and prevents the pinion gear 210
from retreating under the rotation of the ring gear 100 of
the engine.
As the movement of the magnet switch 600 stops
and the cord-shaped member 680 stops pulling the rotation
regulating portion 232 downward, the action of the
return spring portion 233 causes the rotation regulating
portion 232 to return to its original position.
In this way, the pinion rotation regulating member
230, although it is one spring member, performs the
three operations that are the operation of regulating the
rotation of the pinion gear 210 and advancing the pinion
gear 210, the operation of dropping in behind the pinion
gear 210 and preventing the pinion gear 210 from retracting,
and the operation of returning the rotation regulating
portion 232. That is, because a plurality of operations
are carried out by one part, the number of parts
in the starter can be reduced and the assemblability can
be improved.
Also, when the pinion rotation regulating member
230 abuts with the pinion gear 210 and by means of the
rotation of the output shaft 220, while moving the pinion
gear 210 to the ring gear 100 side, the pinion gear 210
abuts with the ring gear 100, because the pinion rotation
regulating member 230 itself bends and rotates the pinion
gear 210 slightly and causes it to mesh with the ring
gear, there is no production of abrasion powder and
there are few parts and the construction can be made
simple.
Also, the pinion rotation regulating member 230, because
the projecting parts of the projections 214 of the
pinion gear 210 are more numerous than the teeth of
the pinion gear 210, can easily engage with the projections
214.
Because the pinion rotation regulating member 230
need only be held with the small force required to regulate
the rotation of the pinion gear 210, it is possible to
move it to the pinion gear 210 side by means of the magnet
switch 600, using the cord-shaped member 680, and
consequently it is possible to increase the freedom with
which the magnet switch 600 is disposed.
Also, the pinion rotation regulating member 230 itself
can prevent the pinion gear 210 from returning when
the pinion gear 210 has meshed with the ring gear 100,
and the number of parts can be made small and the assembly
can be simplified.
Furthermore, because the pinion rotation regulating
member 230 itself integrally comprises the return spring
portion 233 constituting urging means urging to the opposite
side to the pinion gear, by switching the magnet
switch 600 OFF, the pinion rotation regulating member
230 automatically moves away from the pinion gear 210
and the number of parts can be made small and the assembly
can be simplified.
By part of the pinion rotation regulating member 230
having the regulating claw 231 constituting the bar-like
elastic regulating portion, the pinion rotation regulating
member itself can reliably bend.
Also, by the washer 215 being rotatably held on the
end surface of the pinion gear 210, even when the pinion
gear 210 is over-run by the ring gear 100 and rotates at
high speed, because the washer 215 is rotatable with
respect to the pinion gear 210, the abutting portion of
the regulating claw 231 constituting the regulating portion
is not worn much, and the durability can be increased.
(Description of the Pinion Stopping Ring 250)
The pinion stopping ring 250 is fixed in a circular
groove of rectangular cross-section formed around the
output shaft 220. This pinion stopping ring 250 is a piece
of steel of rectangular cross-section processed into a
circular shape; a substantially S-shaped corrugation
251 (an example of engaging means) is formed at each
end, and the convex portion of one is in engagement
with the concave portion of the other and the convex
portion of the other is in engagement with the concave
portion of the first.
(Description of the Planetary Gear Speed Reduction
Mechanism 300)
The planetary gear speed reduction mechanism
300, as shown in Fig. 1, is speed reducing means for
reducing the rotational speed of the output shaft 220 relative
to motor 500, which will be further discussed later,
and increasing the output torque of the motor 500. The
planetary gear speed reduction mechanism 300 is made
up of a sun gear 310 formed on the front-side outer periphery
of the armature shaft 510 (discussed later) of the
motor 500, a plurality of planetary gears 320 which mesh
with this sun gear 310 and rotate around the circumference
of the sun gear 310, a planet carrier 330 which
rotatably supports these planetary gears 320 around the
sun gear 310 and is formed integrally with the output
shaft 220, and an internal gear 340 which is of a cylindrical
shape meshing with the planetary gears 320 at
the outer periphery of the planetary gears 320 and is
made of resin.
(Description of the Overrunning Clutch 350)
The overrunning clutch 350 supports the internal
gear 340 rotatably in one direction only (only the direction
in which it rotates under the rotation of the engine).
The overrunning clutch 350 has a clutch outer 351 constituting
a first cylindrical portion integrally formed in the
front side of the internal gear 340, a circular clutch inner
352 constituting a second cylindrical portion formed in
the rear surface of the center bracket 360 constituting a
fixed side covering the front of the planetary gear speed
reduction mechanism 300 and disposed facing the
clutch outer 351, and a roller 353 accommodated in a
roller housing portion formed inclined to the inner surface
of the clutch outer 351.
(Description of the Center Bracket 360)
The center bracket 360 is shown in detail in Fig. 4
through Fig. 6 and is disposed inside the rear end of the
housing 400. The housing 400 and the center bracket
360 are linked by a ring spring 390 having one end engaged
with the housing 400 and the other end engaged
with the center bracket 360 and are arranged in such a
way that the rotational reaction received by a clutch inner
352 constituting the overrunning clutch 350 is absorbed
by the ring spring 390 and the reaction is not
directly transmitted to the housing 400.
Also, two supporting arms 361 which hold the pinion
rotation regulating member 230 and a regulating shelf
362 on which the lower end of the pinion rotation regulating
member 230 is loaded are mounted on the front
surface of the center bracket 360. Further, a plurality of
cutout portions 363 which mate with convex portions
(not shown in the drawings) on the inner side of the
housing 400 are formed around the center bracket 360.
The upper side cutout portions 363 are used also as air
passages for guiding air from inside the housing 400 into
a yoke 501. Also, a concave portion 364 through which
the cord-shaped member 680 (discussed later) passes
in the axial direction is formed at the lower end of the
center bracket 360.
(Description of the Planet Carrier 330)
The planet carrier 330 is provided at its rear end
with a flange-like projecting portion 331 which extends
radially in order to support the planetary gears 320. Pins
332 extending rearward are fixed to this flange-like projecting
portion 331, and these pins 332 rotatably support
the planetary gears 320 by way of metal bearings 333.
The planet carrier 330 has its front end rotatably
supported by a housing bearing 440 fixed inside the
front end of the housing 400 and a center bracket bearing
370 fixed inside an inner cylindrical portion 365 of
the center bracket 360.
(Description of the Housing 400)
The housing 400 supports the output shaft 220 with
the housing bearing 440 fixed in the front end of the
housing 400 and also is provided with a water barrier
wall 460 which in order to minimize the incursion of rainwater
and the like through the opening portion 410 minimizes
the gap at the lower part of the opening portion
410 between the outer diameter of the pinion gear 210
and the housing 400. Also, two slide grooves extending
axially are provided at the lower part of the front end of
the housing 400, and a shutter 420 which will be further
discussed later is disposed in these slide grooves.
(Description of the Shutter 420)
The shutter 420 consisting of a resinous member
(for example nylon) is mounted on the output shaft 220
and comprises a ring body 421 sandwiched between the
return spring 240 and the pinion gear 210 and a water-barrier
portion 422 which opens and closes an opening
portion 410 in the housing 400. The operation of the
shutter 420 is such that when the starter starts to operate
and the pinion gear 210 shifts forward along the output
shaft 220 the ring body 421 shifts forward together
with the pinion gear 210. When this happens, the water-barrier
portion 422 integral with the ring body 421 shifts
forward and opens the opening portion 410 of the housing
400. When the starter stops operating and the pinion
gear 210 shifts backward along the output shaft 220, the
ring body 421 also shifts backward together with the pinion
gear 210. When this happens, the water-barrier portion
422 integral with the ring body 421 also shifts backward
and closes the opening portion 410 of the housing
400. As a result, the shutter 420, which constitutes
opening and closing means, by means of the water-barrier
portion 422 prevents rainwater and the like which is
splashed by the centrifugal force of the ring gear 100
from getting inside the housing 400 when the starter is
not operating.
(Description of the Motor 500)
The motor 500 is enclosed by a yoke 501 having a
through hole 503, motor spacer wall 800, and a brush
holding member 900 which will be discussed later. The
motor spacer wall 800 houses the planetary gear speed
reduction mechanism 300 between itself and the center
bracket 360, and also fulfills the role of preventing lubricating
oil inside the planetary gear speed reduction
mechanism 300 from getting into the motor 500.
The motor 500, as shown in Fig. 1, is made up of
an armature 540 comprising the armature shaft 510 and
an armature core 520 and armature coils 530 which are
mounted on and rotate integrally with this armature shaft
510, and fixed poles 550 which rotate the armature 540,
and the fixed poles 550 are mounted around the inside
of the yoke 501.
(Description of the Armature Coils 530)
For the armature coils 530, in this embodiment
shown in detail in Fig. 7, multiple (for example 25) upper
layer coil bars 531 and the same number of lower layer
coil bars 532 as these upper layer coil bars 531 are
used, and 2-layer-winding coils wherein the respective
upper layer coil bars 531 and the lower layer coil bars
532 are stacked in the radial direction are employed.
The upper layer coil bars 531 and lower layer coil bars
532 are paired, and the ends of the upper layer coil bars
531 and the ends of the lower layer coil bars 532 are
electrically connected to constitute ring-shaped coils.
(Description of the Upper Layer Coil Bars 531)
The upper layer coil bars 531, as shown in Fig. 7,
are made of a material having excellent electrical conductivity
(for example copper), and are each provided
with an upper layer coil arm 533 which extends axially
in parallel with the fixed poles 550 and is held in the outer
sides of slots 524 and two upper layer coil ends 534
which are bent inward from both ends of the upper layer
coil arm 533 and extend in a direction orthogonal to the
axial direction of the armature shaft 510. The upper layer
coil arm 533 and the two upper layer coil ends 534 may
be a member integrally molded by cold casting, may be
a member shaped by bending in a press into a U-shape,
or may be a member formed by joining an upper layer
coil arm 533 and two upper layer coil ends 534 made as
separate parts by a joining method such as welding.
(Description of the Lower Layer Coil Bars 532)
The lower coil bars 532, like the upper coil bars 531,
are made from a material having excellent electrical
conductivity (for example copper), and each comprise
a lower layer coil arm 536 which extends axially in parallel
with respect to the fixed poles 550 and is held in
the inner sides of slots 524 and two lower layer coil ends
537 which are bent inward from the ends of this lower
layer coil arm 536 and extend orthogonal to the axial
direction of the armature shaft 510. The lower layer coil
arm 536 and the two lower layer coil ends 537, like the
upper layer coil bar 531, may be a member integrally
molded by cold casting, may be a member shaped by
bending in a press into a U-shape, or may be a member
formed by joining a lower layer coil arm 536 and 2 lower
layer coil ends 537 made as separate parts by a joining
method such as welding.
Insulation between the upper layer coil ends 534
and the lower layer coil ends 537 is secured by insulating
spacers 560, and insulation between the lower layer
coil ends 537 and the armature core 520 is secured by
an insulating ring 590 made of resin (for example nylon
or phenol resin).
(Description of the Yoke 501)
The yoke 501, as shown in Fig. 8, is a cylindrical
body formed by rolling a steel plate, and around it are
formed a plurality of concave grooves 502 extending axially
and sunk toward the inner circumference. These
concave grooves 502, as well as disposing through
bolts, are used for positioning fixed poles 550 around
the inner circumference of the yoke 501.
(Description of the Fixed Poles 550)
In this embodiment permanent magnets are used
for the fixed poles 550 and, as shown in Fig. 8, they comprise
a plurality of (for example 6) main poles 551 and
inter-pole poles 552 disposed between these main
poles 551. Field coils which generate magnetic force by
electrical current flow may be used instead of permanent
magnets for the fixed poles 550.
The main poles 551 are positioned by the ends of
the inner sides of channel grooves 502 in the above-mentioned
yoke 501, and are fixed in the yoke 501 by
fixing sleeves 553 disposed around the inside of the
fixed poles 550 with the inter-pole poles 552 disposed
between the main poles 551.
(Description of the Magnet Switch 600)
The magnet switch 600, as shown in Fig. 1, Fig. 9
and Fig. 10, is held in a brush holder 900 which will be
discussed later, is disposed inside an end frame 700
which will be discussed later, and is fixed so as to be
substantially orthogonal to the armature shaft 510.
In the magnet switch 600, electrical current drives
a plunger 610 upward, and two contacts (a lower movable
contact 611 and an upper movable contact 612)
which move together with the plunger 610 are sequentially
caused to abut with the head portion 621 of a terminal
bolt 620 and an abutting portion 631 of a fixed
contact 630. A battery cable not shown in the drawings
is connected to the terminal bolt 620.
The magnet switch 600 is structured inside a magnet
switch cover 640 which is cylindrical and has a bottom
and is made from magnetic parts (for example made
of iron). The magnet switch cover 640 is for example a
pliable steel plate press-formed into a cup shape, and
in the center of the bottom of the magnet switch cover
640 there is a hole 641 through which the plunger 610
passes movably in the vertical direction. Also, the upper
opening of the magnet switch cover 640 is closed off by
a stationary core 642 made of a magnetic body (for example
made of iron).
The stationary core 642 consists of an upper large
diameter portion 643, a lower middle diameter portion
644, and a still lower small diameter portion 645, and
the stationary core 642 is fixed in the upper opening of
the magnet switch cover 640 by the outer periphery of
the large diameter portion 643 being caulked to the inner
side of the upper end of the magnet switch cover 640.
The upper end of an attracting coil 650 is fitted around
the middle diameter portion 644. The upper end of a
compression coil spring 660 which urges the plunger
610 downward is fitted around the periphery of the small
diameter portion 645 of the stationary core 642.
The attracting coil 650 is attracting means which
generates magnetism when a current flows through it
and attracts the plunger 610, and the attracting coil 650
is provided with a sleeve 651 which has its upper end
fitted to the middle diameter portion 644 of the stationary
core 642 and covers the plunger 610 slidably in the vertical
direction. This sleeve 651 is made by rolling up a
non-magnetic thin plate (for example copper plate,
brass, stainless steel), and insulating washers 652
made of resin or the like are provided at the upper and
lower ends of this sleeve 651. Around the sleeve 651
between these 2 insulating washers 652 there is wound
a thin insulating film (not shown in the drawings) made
of resin (for example cellophane, nylon film) or paper,
and around that insulating film is wound a predetermined
number of turns of a thin enamel wire, whereby
the attracting coil 650 is constituted.
The plunger 610 is made of a magnetic metal (for
example iron) and has a substantially cylindrical shape
comprising an upper small diameter portion 613 and a
lower large diameter portion 614. The lower end of the
compression coil spring 660 is fitted to the small diameter
portion 613, and the large diameter portion 614,
which is relatively long in the axial direction, is held slidably
vertically in the sleeve 651.
A plunger shaft 615 extending upward from the
plunger 610 is fixed to the upper end of the plunger 610.
This plunger shaft 615 projects upward through a
through hole provided in the stationary core 642. An upper
movable contact 612 is fitted around the plunger
shaft 615 above the stationary core 642 slidably vertically
along the plunger shaft 615. This upper movable
contact 612, as shown in Fig. 9, is limited by a stopping
ring 616 fitted to the upper end of the plunger shaft 615
so that it does not move upward of the upper end of the
plunger shaft 615. As a result, the upper movable contact
612 is vertically slidable along the plunger shaft 615
between the stopping ring 616 and the stationary core
642. The upper movable contact 612 is urged upward
at all times by a contact pressure spring 670 consisting
of a sheet plate spring fitted to the plunger shaft 615.
The upper movable contact 612 is made of a metal
such as copper having excellent conductivity, and when
both ends of the upper movable contact 612 move upward
they abut with the two abutting portions 631 of the
fixed contact 630. The lead wires 910a of a pair of brushes
910 are electrically and mechanically fixed to the upper
movable contact 612 by caulking or welding or the
like. Also, the end portion of a resistor member 617 constituting
a plurality of (in this embodiment, two) limiting
means is inserted and electrically and mechanically
fixed in a groove portion of the upper movable contact
612.
The lead wires 910a are electrically and mechanically
fixed to the upper movable contact 612 by caulking
or welding, but the upper movable contact 612 and the
lead wires 910a of the brushes 910 may alternatively be
formed integrally.
The resistor member 617 is for rotating the motor
500 at low speed when the starter starts to operate, and
consists of a metal wire of high resistance wound
through several turns. A lower movable contact 611 located
below the head portion 621 of the terminal bolt
620 is fixed by caulking or the like to the other end of
the resistor member 617.
The lower movable contact 611 is made of a metal
such as copper having excellent conductivity, and when
the magnet switch 600 stops and the plunger 610 is in
its downward position abuts with the upper surface of
the stationary core 642, when the resistor member 617
moves upward along with the movement of the plunger
shaft 615, before the upper movable contact 612 abuts
with the abutting portion 631 of the fixed contact 630 it
abuts with the head portion 621 of the terminal bolt 620.
The lower surface of the plunger 610 is provided
with a recess portion 682 which accommodates a
sphere 681 provided at the rear end of the cord-shaped
member 680 (for example a wire). A female thread 683
is formed on the inner wall of this female thread 683. A
fixing screw 684 which fixes the sphere 681 in the recess
portion 682 is screwed into this recess portion 682. This
fixing screw 684 is also used to perform adjustment of
the length of the cord-shaped member 680, by adjusting
the extent to which the fixing screw 684 is screwed into
the female thread 683. The length of the cord-shaped
member 680 is adjusted so that when the plunger shaft
615 moves upward and the lower movable contact 611
abuts with the terminal bolt 620 the regulating claw 231
of the pinion rotation regulating member 230 mates with
the projections 214 of the outer periphery of the pinion
gear 210. The female thread 683 and the fixing screw
684 constitute an adjusting mechanism.
With such a construction, because with respect to
the movement of the plunger 610 of the magnet switch
600, via the cord-shaped member 680, the pinion rotation
regulating member 230 is moved to the pinion gear
210 side, conventional link mechanisms and levers and
the like are not necessary and the number of parts can
be reduced, and also even if the pinion gear 210 fails to
move away from the ring gear 100, bending in the cord-shaped
member 680 itself causes the plunger 610 to
return to its original position, and the upper movable
contact 612 can move away from the fixed contact 630.
Also, because all that is necessary is to cause the
regulating claw 231 of the pinion rotation regulating
member 230 to engage with the projections 214 on the
pinion gear 210, this regulating claw 231 can be reliably
moved by the cord-shaped member 680.
By making the cord-shaped member 680 a wire, the
durability can be increased.
Also, by disposing the adjusting mechanism consisting
of the female thread 683 and the fixing screw 684
between the plunger 610 and the cord-shaped member
680 and screwing the fixing screw 684 into the female
thread 683, the length of the cord-shaped member 680
can be easily adjusted.
Also, because the lead wires 910a of the brushes
910 are directly connected to the upper movable contact
612, heat generated at the brushes 910 is efficiently radiated
via the lead wires 910a, the upper movable contact
612 and the terminal bolt 620 from the battery cable
connected to the terminal bolt 620 and positioned outside
the starter, and increases in the life of the brushes
910 can be attempted.
Furthermore, because the plunger shaft 615 of the
magnet switch 600 is disposed substantially orthogonal
to the motor axis, compared to a case wherein the plunger
shaft 615 of the magnet switch 600 is disposed axially,
the axial direction dimension of the starter can be shortened
and the stroke through which the plunger shaft 615
is required to pull the cord-shaped member 680 can be
set small, and further downsizing of the magnet switch
600 can be attempted.
Furthermore, because the plunger 615 of the magnet
switch 600 is disposed orthogonal with respect to
the axial direction of the armature shaft 510, only the
diametral direction length of the magnet switch 600 adds
to the axial direction length of the overall starter, and the
build of the whole starter is not made large.
Furthermore, because the magnet switch 600 is
housed inside the end frame 700, it does not readily suffer
damage from water and the like which has entered
through the opening 410 in the housing 400.
(Description of the End Frame 700)
The end frame 700, as shown in Fig. 11, is a magnet
switch cover made of resin (for example phenol resin),
and accommodates the magnet switch 600.
Spring holding pillars 710 which hold compression
coil springs 914 which urge the brushes 910 forward are
mounted projecting from the rear surface of the end
frame 700 in correspondence with the positions of the
brushes 910.
Also, the compression coil springs 914, as shown
in Fig. 1, are disposed radially outward with respect to
the axial direction of the plunger 610 of the magnet
switch 600.
The terminal bolt 620 is a steel bolt which passes
through the end frame 700 from the inside and projects
from the rear of the end frame 700 and has at its front
end a head portion 621 which abuts with the inner surface
of the end frame 700. The terminal bolt 620 is fixed
to the end frame 700 by a caulking washer 622 being
attached to the terminal bolt 620 projecting rearward of
the end frame 700. A copper fixed contact 630 is fixed
to the front end of the terminal bolt 620 by caulking. The
fixed contact 630 has one or a plurality of (in this embodiment,
two) abutting portions 631 positioned at the
top end of the inside of the end frame 700, and these
abutting portions 631 are mounted so that the upper surface
of the upper movable contact 612 which is moved
up and down by the operation of the magnet switch 600
can abut with the lower surfaces of the abutting portions
631.
Further, the spring length of the compression coil
springs 914 can use the radial direction length of the
magnet switch 600, a suitable spring stress and load can
be set, and the life of the compression coil springs 914
can be greatly increased.
(Description of the Brush Holder 900)
The brush holder 900, as well as the roles of separating
the inside of the yoke 501 and the inside of the
end frame 700 and rotatably supporting the rear end of
the armature shaft 510 by way of the brush holder bearing
564, also fulfills the role of a brush holder, the role
of holding the magnet switch 600, and the role of holding
a pulley 690 which guides the cord-shaped member
680. The brush holder 900 has a hole portion not shown
in the drawings through which the cord-shaped member
680 passes.
The brush holder 900 is a spacing wall made of a
metal such as aluminum molded by a casting method
and, as shown in Fig. 12 through Fig. 14, has a plurality
of (in this embodiment, two upper and two lower) brush
holding holes 911, 912 which hold the brushes 910 in
the axial direction. The upper brush holding holes 911
are holes which hold brushes 910 which receive a plus
voltage, and these upper brush holding holes 911 hold
the brushes 910 by way of resin (for example nylon, phenol
resin) insulating cylinders 913 (Fig. 13 is a cross-section
taken along XIII-XIII of Fig. 12, and Fig. 14 is a
cross-section taken along XIV-XIV of Fig. 12). The lower
brush holding holes 912 are holes which hold brushes
910 connected to ground, and these lower brush holding
holes 912 hold the respective brushes 910 directly
therein.
In this way, by holding the brushes 910 by means
of the brush holder 900, there is no need to provide the
starter with independent brush holders. As a result, the
number of parts in the starter can be reduced and assembly
man-hours can be reduced.
The brushes 910 are urged against the upper layer
coil ends 534 at the rear ends of the armature coils 530
by the compression coil springs 914.
The lead wires 910a of the upper brushes 910 are
electrically and mechanically joined by a joining method
such as welding or caulking to the upper movable contact
612 which is moved by the magnet switch 600. The
lead wires 910a of the lower brushes 910 are caulked
and thereby electrically and mechanically joined to a
concave portion 920 formed in the rear surface of the
brush holder 900. In this embodiment a pair of lower
brushes 910 are provided, one lead wire 910a is connected
to the pair of lower brushes 910, and the middle
of the lead wire 910a is caulked in the concave portion
920 formed in the rear surface of the brush holder 900.
Two seats 930 with which the front side of the magnet
switch 600 abuts and two fixing pillars 940 which
hold the periphery of the magnet switch 600 are formed
on the rear side of the brush holder 900.
The seats 930 are shaped to match the external
shape of the magnet switch 600 in order to abut with the
magnet switch 600, which has a cylindrical exterior. The
two fixing pillars 940, with the magnet switch 600 in abutment
with the seats 930, by having their rear ends
caulked to the inner side, hold the magnet switch 600.
A pulley holding portion 950 which holds a pulley
690 which converts the direction of movement of the
cord-shaped member 680 from the vertical direction of
the magnet switch 600 into the axial direction thereof is
formed on the lower side of the rear side of the brush
holder 900.
(Operation of the Invention)
Next, the operation of the starter described above
will be explained with reference to the electrical circuit
diagrams Figs. 15A through 15C.
When a key switch 10 is set to the start position by
a driver as shown in Fig. 15A, electricity flows from a
battery 20 to the attracting coil 650 of the magnet switch
600. When current flows through the attracting coil 650,
the plunger 610 is pulled by the magnetic force produced
by the attracting coil 650, and the plunger 610
ascends from its lower position to its upper position
(from right to left in Fig. 15A).
When the plunger 610 starts to ascend, together
with the ascent of the plunger shaft 615 the upper movable
contact 612 and the lower movable contact 611 ascend,
and the rear end of the cord-shaped member 680
also ascends. When the rear end of the cord-shaped
member 680 ascends, the front end of the cord-shaped
member 680 is pulled down, and the pinion rotation regulating
member 230 descends. When the descent of the
pinion rotation regulating member 230 causes the regulating
claw 231 to mate with the projections 214 of the
periphery of the pinion gear 210, the lower movable contact
611 abuts with the head portion 621 of the terminal
bolt 620. The voltage of the battery 20 is impressed on
the terminal bolt 620, and the voltage of the terminal bolt
620 is transmitted through the lower movable contact
611 → the resistor member 617 → the upper movable
contact 612 → the lead wires 910a to the upper brushes
910. That is, the low voltage passing through the resistor
member 617 is transmitted through the upper brushes
910 to the armature coils 530. Because the lower brushes
910 are constantly grounded through the brush holder
900, a current flows at low voltage through the armature
coils 530 constituted in coil form by the paired upper
layer coil bars 531 and lower layer coil bars 532. When
this happens, the armature coils 530 generate a relatively
weak magnetic force, this magnetic force acts on
(attracts or repels) the magnetic force of the fixed poles
550, and the armature 540 rotates at low speed.
When the armature shaft 510 rotates, the planetary
gears 320 of the planetary gear speed reduction mechanism
300 are rotationally driven by the sun gear 310
on the front end of the armature shaft 510. When the
planetary gears 320 exert a rotational torque through the
planet carrier 330 on the internal gear 340 in the direction
which rotationally drives the ring gear 100, the rotation
of the internal gear 340 is limited by the operation
of the overrunning clutch 350. That is, because the internal
gear 340 does not rotate, the rotation of the planetary
gears 320 causes the planet carrier 330 to rotate
at low speed. When the planet carrier 330 rotates, the
pinion gear 210 also rotates, but because the pinion
gear 210 has its rotation limited by the pinion rotation
regulating member 230 the pinion gear 210 advances
along the helical spline 221 on the output shaft 220.
Together with the advance of the pinion gear 210,
the shutter 420 also advances, and opens the opening
portion 410 of the housing 400. The advance of the pinion
gear 210 causes the pinion gear 210 to mesh completely
with the ring gear 100 and then abut with the pinion
stopping ring 250. Also, when the pinion gear 210
advances, the regulating claw 231 disengages from the
projections 214 of the pinion gear 210 and after that the
front end of the regulating claw 231 drops to the rear
side of the washer 215 disposed on the rear side of the
pinion gear 210.
With the pinion gear 210 advanced, the upper movable
contact 612 abuts with the abutting portion 631 of
the fixed contact 630 as shown in Fig. 15B. When this
happens, the battery voltage of the terminal bolt 620 is
directly transmitted through the upper movable contact
612 → the lead wires 910a to the upper brushes 910.
That is, a high current flows through the armature coils
530 consisting of the upper coil bars 531 and the lower
coil bars 532, the armature coils 530 generate a strong
magnetic force and the armature 540 rotates at high
speed.
The rotation of the armature shaft 510 is slowed and
has its rotational torque increased by the planetary gear
speed reduction mechanism 300 and rotationally drives
the planet carrier 330. At this time, the front end of the
pinion gear 210 abuts with the pinion stopping ring 250
and the pinion gear 210 rotates integrally with the planet
carrier 330. Because the pinion gear 210 is meshing
with the ring gear 100 of the engine, the pinion gear 210
rotationally drives the ring gear 100 and rotationally
drives the output shaft of the engine.
Next, when the engine starts and the ring gear 100
of the engine rotates faster than the rotation of the pinion
gear 210, the action of the helical spline creates a force
tending to retract the pinion gear 210. However, the regulating
claw 231 which has dropped to behind the pinion
gear 210 prevents the pinion gear 210 from retracting,
prevents early disengagement of the pinion gear 210,
and enables the engine to be started surely.
When the engine starting causes the ring gear 100
to rotate faster than the rotation of the pinion gear 210,
the rotation of the ring gear 100 rotationally drives the
pinion gear 210. When this happens, the rotational
torque transmitted from the ring gear 100 to the pinion
gear 210 is transmitted through the planet carrier 330 to
the pins 332 which support the planetary gears 320.
That is, the planetary gears 320 are driven by the planet
carrier 330. When this happens, because a torque rotationally
opposite to that during engine starting is exerted
on the internal gear 340, the overrunning clutch 350 allows
the rotation of the ring gear 100. That is, when a
torque rotationally opposite to that during engine starting
is exerted on the internal gear 340, the roller 353 of
the overrunning clutch 350 detaches to outside the concave
portion 355 of the clutch inner 352 and rotation of
the internal gear 340 becomes possible.
In other words, the relative rotation with which the
ring gear 100 rotationally drives the pinion gear 210
when the engine starts is absorbed by the overrunning
clutch 350, and the armature 540 is never rotationally
driven by the engine.
When the engine starts, the driver releases the key
switch 10 from the start position as shown in Fig. 15C
and the flow of current to the attracting coil 650 of the
magnet switch 600 is stopped. When the flow of current
to the attracting coil 650 stops, the plunger 610 is returned
downward by the action of the compression coil
spring 660.
When this happens, the upper movable contact 612
moves away from the abutting portion 631 of the fixed
contact 630, and after that the lower movable contact
611 also moves away from the head portion 621 of the
terminal bolt 620, and the flow of current to the upper
brushes 910 is stopped.
When the plunger 610 is returned downward, the
action of the return spring portion 236 of the pinion rotation
regulating member 230 causes the pinion rotation
regulating member 230 to return upward, and the regulating
claw 231 moves away from the rear of the pinion
gear 210. When this happens, the pinion gear 210 is
returned rearward by the action of the return spring 240,
the meshing of the pinion gear 210 with the ring gear
100 of the engine is disengaged, and the rear end of the
pinion gear 210 abuts with the flange-like projecting portion
222 of the output shaft 220. That is, the pinion gear
210 is returned to the position it was in before the starter
was started.
Also, the plunger 610 being returned downward
causes the lower movable contact 611 to abut with the
upper surface of the stationary core 642 of the magnet
switch 600, and the lead wires of the upper brushes 910
conduct electrical current in the order the upper movable
contact 612 → the resistor member 617 → the lower
movable contact 611 → the stationary core 642 → the
magnet switch cover 640 → the brush holder 900. In other
words, the upper brushes 910 and the lower brushes
910 short-circuit through the brush holder 900. Meanwhile,
inertial rotation of the armature 540 generates an
electromotive force in the armature coils 530. Because
this electromotive force is short-circuited through the upper
brushes 910, the brush holder 900 and the lower
brushes 910, a braking force is exerted on the inertial
rotation of the armature 540. As a result, the armature
540 rapidly stops.
(Advantages of the Embodiment)
In the starter of this embodiment as described with
reference to Fig. 1, Fig. 2, Figs. 3A and 3B, when the
pinion rotation regulating member 230 constituting pinion
regulating means abuts with the pinion 200 and the
rotation of the output shaft 220 moves the pinion gear
210 to the ring gear side and the pinion gear 210 abuts
with the ring gear 100, the pinion regulating means itself
bends and allows the pinion gear 210 to gradually rotate
and mesh with the ring gear and consequently there is
no generation of abrasion powder and a simple constitution
with few parts can be adopted.
Also, because the axial grooves 213 with which the
regulating claw 231 of the pinion rotation regulating
member 230 engages are more numerous than the gear
number of the pinion gear 210, it can easily engage with
the axial grooves.
Furthermore, because the pinion rotation regulating
member 230 need only hold the pinion gear 210 with the
small force required to regulate the rotation of the pinion
gear 210, the pinion rotation regulating member 230 can
be moved to the pinion gear 210 side by the magnet
switch 600 by way of the cord-shaped member 680, and
the freedom with which the magnet switch 600 is disposed
can be increased.
Also, the regulating claw 231 of the pinion rotation
regulating member 230 itself can attain the pinion return
prevention when the pinion gear 210 has meshed with
the ring gear 100, and the number of parts can be made
small and the assembly can be simplified.
Furthermore, because the pinion rotation regulating
member 230 itself integrally comprises the return spring
portion 233 constituting urging means for urging the
movement to the opposite side to the pinion gear 210,
by switching the magnet switch 600 OFF, by means of
the spring portion 233, the pinion rotation regulating
member 230 moves away from the pinion gear 230, and
the number of parts can be made small and the assembly
can be simplified.
Because until the pinion gear 210 abuts with the ring
gear 100 the resistor member 617 constituting limiting
means makes the rotation of the output shaft 220 slow
and the pinion gear 210 is moved to the ring gear 100
side slowly, it is not necessary to make the rigidity of the
pinion rotation regulating member 230 strong, and it is
possible to make the shock when the pinion gear 210
abuts with the ring gear 100 small.
Also, by holding the washer 215 rotatably on the
end surface of the pinion gear 210, even when the pinion
gear 210 is over-run by the ring gear 100 and rotates at
high speed, because the washer 215 is rotatable with
respect to the pinion gear 210, there is little wear on the
abutting portion of the regulating claw 231 of the pinion
rotation regulating member 230, and the durability can
be increased.
Furthermore, because the washer 215 is heat-treated
simultaneously with the pinion gear 210, it is possible
to dispense with a process for making the hardness of
the washer 215 above a predetermined value.
Also, by the movement of the plunger 610 of the
magnet switch 600, by causing the regulating claw 231
to abut with the pinion gear 210 while causing the return
spring portion 233 constituting urging means to move,
by means of the compression force of the return spring
233, the regulating claw 231 can be reliably moved away
from the pinion gear 210 side.
(Other Embodiment)
In the second embodiment shown in Fig. 16, the
magnet switch 600 in embodiment 1 is disposed parallel
to the motor 500 and the pinion rotation regulating member
230 is operatively linked with the magnet switch 600
through the wire 680.
While this invention has been described in connection
with what is presently considered most preferred
embodiments, this invention is not to be limited to the
disclosed embodiments, but is meant to cover all modifications
and equivalent arrangement within the scope
of the appended claims.