JPH0663491B2 - Starter with planetary gear reduction mechanism - Google Patents

Description

TECHNICAL FIELD The present invention relates to a starter with a planetary gear speed reduction mechanism for starting an internal combustion engine.

[Conventional technology]

As shown in Japanese Utility Model Application Laid-Open No. 50-129811, the conventional one has a spring arranged between the internal gear and the center bracket by the pressing force of the spring itself.

However, in the above-mentioned conventional one, since the spring is arranged between the internal gear and the center bracket, the length of the starter in the axial direction is lengthened by the spring, the size of the starter is increased, and the spring is used as the starter. There is a problem in that the slip torque cannot be measured unless it is inserted into the inside, and it is difficult to set the slip torque.

Therefore, the applicant of the present application has already applied for a structure that can solve the above problems (Japanese Patent Application No. 59-229885).
issue).

[Problems to be Solved by the Invention]

However, in the above-mentioned prior application, the internal gear is fixed by being sandwiched between the yoke and the center bracket, but there is a gap between the sandwiching portion of the yoke and the center bracket and the internal gear due to design error or the like. May occur, and the clearance may cause the internal gear to rattle in the axial direction, resulting in poor power transmission.

In addition, foreign matter such as brush powder of the starter motor may enter the planetary gear speed reduction mechanism and deteriorate the meshability of each gear, or may enter the bearing between the center bracket and the armature shaft and deteriorate slidability. There is a risk of

Therefore, the present invention is to mount the shock absorber without increasing the total length of the starter while preventing the axial movement of the internal gear or preventing foreign matter from entering from the starter motor side, and An object of the present invention is to provide a starter capable of easily setting a slip torque.

[Means for Solving the Problems]

 The above object is achieved by the following first and second inventions.

A first invention is a drive shaft having an armature shaft of a starter motor, a drive shaft arranged on the same axis as the armature shaft, and a protrusion projecting radially outward from an end of the armature shaft, and the drive shaft. A pinion that is helically spline-coupled to the outer periphery of the drive shaft and that meshes with the link gear of the internal combustion engine; a sun gear that is formed on the outer periphery of the armature shaft of the starter motor; and a planetary gear that meshes with the sun gear and that is provided on the protrusion of the drive shaft , Having an internal gear that is meshed with this planetary gear and that is arranged on the fixed side, and through the sun gear, the planetary gear, and the internal gear, reduces the rotation of the armature shaft to the drive shaft. A planetary gear reduction mechanism that transmits the drive shaft and the front The drive shaft or the armature shaft is rotatably supported by a cylindrical portion arranged on one of the outer peripheries of the armature shaft via a bearing, and a disc portion extending from the end of the cylindrical portion in the outer peripheral radial direction. A center bracket, a rotary disc that is arranged so as not to be rotatable in the circumferential direction with respect to the internal gear, and is arranged on the outer periphery of the cylindrical portion of the center bracket, and the rotary disc is the disc portion of the center bracket. Alternatively, a spring which is arranged so as not to be rotatable in the circumferential direction with respect to the disc portion and is pressed against a fixed disk arranged on the outer periphery of the cylindrical portion of the center bracket, and which is arranged on the outer periphery of the cylindrical portion of the center bracket. A shock absorber having the rotating disk and a fixing means for holding the spring on the outer periphery of the cylindrical portion of the center bracket, A pressing means for pressing the serial internal gear in the axial direction, a starter with a planetary gear reduction mechanism comprising a.

A second invention is a drive shaft having a starter motor armature shaft, a drive shaft arranged on the same axis as the armature shaft, and a protrusion protruding radially outward from an end of the armature shaft side. A helical spline coupled to the outer periphery of the pinion, which meshes with the ring gear of the internal combustion engine, a sun gear formed on the outer periphery of the armature shaft of the starter motor, and a planetary gear which meshes with the sun gear and is provided on the protruding portion of the drive shaft, It has an internal gear that is meshed with this planetary gear and arranged on the fixed side, and reduces the rotation of the armature shaft and transmits it to the drive shaft via the sun gear, the planetary gear and the internal gear. A planetary gear reduction mechanism, the drive shaft and the front The drive shaft or the armature shaft is rotatably supported by a cylindrical portion arranged on one of the outer peripheries of the armature shaft via a bearing, and a disc portion extending from the end of the cylindrical portion in the outer peripheral radial direction. A center bracket, a rotary disc that is arranged so as not to be rotatable in the circumferential direction with respect to the internal gear, and is arranged on the outer periphery of the cylindrical portion of the center bracket, and the rotary disc is the disc portion of the center bracket. Alternatively, a spring which is arranged so as not to be rotatable in the circumferential direction with respect to the disc portion and is pressed against a fixed disk arranged on the outer periphery of the cylindrical portion of the center bracket, and which is arranged on the outer periphery of the cylindrical portion of the center bracket. A shock absorber having the rotating disk and a fixing means for holding the spring on the outer periphery of the cylindrical portion of the center bracket, The planetary gear speed reduction mechanism and the center bracket are arranged between the armature and the starter motor, the hole penetrates the armature shaft and faces the outer periphery of the armature shaft with a minute gap, and from this hole, A starter with a planetary gear speed reduction mechanism, comprising: a planetary gear speed reduction mechanism and a cylindrical portion extending toward the center bracket side; and a partition wall having a circular disk portion that continuously extends to the cylindrical portion and extends in the outer diameter direction.

[Operation and effect of the invention]

According to the first aspect of the invention, (a) the shock absorber is arranged by utilizing the space on the outer circumference of the cylindrical portion of the center bracket, so that the shock absorber can be mounted without increasing the overall length, b) Since the shock absorber is held by the fixing means on the outer periphery of the cylindrical portion of the center bracket, the slip torque of the shock absorber can be set before being assembled inside the starter, and the slip torque can be easily set. c) Since the internal gear is pressed in the axial direction by the pressing member, rattling of the internal gear can be prevented, and good power transmission can be performed.

According to the second invention, in addition to (a) and (b) above, (d) the planetary gear speed reduction mechanism and the center bracket are separated from the armature of the starter motor by a partition wall, and the armature side with respect to the disc portion. It is possible to make it difficult for foreign matter to enter due to the cylindrical portion extending in the direction.

〔Example〕

The present invention will be described below with reference to the embodiments shown in the drawings. First
In the first embodiment shown in the figure, 1 is a starter motor, 2 is
Is a magnet switch. At both ends of the cylindrical yoke 3 of the starter motor 1, the first and second step portions 3a, 3 are respectively provided.
b is formed. An exciting coil 4 is provided on the inner circumference of the yoke 3.
The pole core 4 around which a is wound is attached. An armature 5 is arranged on the inner peripheral side of the pole core 4, and an armature shaft 6 is provided at the center. One end of the armature shaft 6 is rotatably supported by the end frame 7 via a bearing 7a. A brush 9 is slidably arranged on the outer circumference of the commutator 8.

A sun gear 10 is formed on the outer periphery of the other end of the armature shaft 6. In addition, on the same axis as the armature shaft 6, the bearing 11
The drive shaft 12 is arranged via the. On the side of the starter motor 1 that is one end of the drive shaft 12, a disk-shaped protruding portion 13 that protrudes in the outer peripheral radial direction is formed, and the other end is axially supported by the housing 15 via a bearing 14. There is. Further, the protrusions 13 have through holes 13a at equal intervals.
Are formed.

Then, a helical spline portion 12a is formed on the outer periphery of the drive shaft 12, and the helical spline portion 12a is formed.
The spline tube 20 is connected to the helical spline. The spline tube 20 is connected to the pinion 22 via the clutch outer 21a, the roller 21b, and the clutch inner 21c that form the one-way clutch 21. Further, the ring gear 23 meshes with the pinion 22 to start the internal combustion engine. The shift lever 24 has one end engaged with the outer periphery of the spline tube 20 and the other end engaged with the joint portion 25a of the plunger 25 of the magnet switch 2.

Next, the planetary gear speed reduction mechanism and the shock absorber will be described. The planetary gear 30 meshing with the outer periphery of the sun gear 10 is
The pin 31 is press-fitted into the through hole 13a of the protrusion 13 and is rotatably held via a bearing 31a. Furthermore, the planetary gear 30
An internal gear 32 is arranged on the outer peripheral side of.
The internal gear 32 has a cylindrical shape, and teeth 32a that mesh with the planetary gear 30 are formed in about half of the inner circumference on the armature 5 side. A plurality of first recesses 32b are formed in the circumferential direction at the inner peripheral end of the internal gear 32 on the side opposite to the armature 5.
Are formed. Furthermore, the internal gear 32 has
Through a gap in the protruding portion 13 of the drive shaft 12,
The armature 6 and the protrusion 32c that faces each other and protrudes toward the inner peripheral side.
The second concave portion 32d formed on the outer periphery of the side is formed. And sun gear 10, planet gears, internal gear
32 constitutes a planetary gear reduction mechanism.

Then, a disc 33 is inserted between the internal gear 32 and the first step portion 3a, and the inner periphery of the disc 33 is bent in the axial direction to bend the coil end of the armature 5 and the armature shaft. 6, a cylindrical portion 33a is formed between the cylindrical portion 33a and the disk 6, and the partition wall formed by the cylindrical portion 33a and the disc 33 prevents foreign matter from entering the planetary gear reduction mechanism side.

The center bracket 35 includes a first cylindrical portion 35a arranged on the outer periphery of the drive shaft 12 via a bearing 34, and a first cylindrical portion 35a.
The disk portion 35b formed on the radially outer side of the end portion of the cylindrical portion 35a on the side of the anti-planetary gear reduction mechanism, and bent from the outer peripheral end of the disk portion 35b so as to be parallel to the first cylindrical portion 35a. It is composed of a second cylindrical portion 35c which extends and which has the internal gear 32 arranged on the inner peripheral side. And the second cylindrical portion 35c
The center bracket 35 is fixed by sandwiching the both ends between the housing 15 and the first step portion 3a of the yoke 3.

Then, on the side of the first cylindrical portion 35a of the disc portion 35b, three punching portions 35d for positioning are formed at equal intervals.
Further, on the outer circumference of the first cylindrical portion 35a, five grooves 35e are formed at equal intervals in the axial direction, and at the same time, the first cylindrical portion 35a is formed.
A thread groove 35f is formed on the outer periphery of the. A recess 35g is formed in the disk portion 35b of the center bracket 35 that faces the end surface of the internal gear 32, and a wave washer (pressing means) 36 is inserted into the recess 35g so that the internal gear 32 and The plate 33 is pressed against the end surface of the yoke 3 to fix the internal gear 32.

Further, 37 and 38 are first and second friction plates having a ring shape. Further, the outer circumferences of the first and second friction plates 37, 38 are
It is arranged on the inner circumference of the internal gear 32 with a slight gap.

Further, the rotary disc 39 has a ring-like shape having the same size as the first and second friction plates 37, 38, and projecting portions 39a are formed on the outer peripheral side at equal intervals. Null gear
It is inserted into the first recess 32b of 32. Therefore, the rotary disc 39 is movable with respect to the internal gear 32 toward the disc portion 35b of the center bracket 35, and is not rotatable in the circumferential direction.

The fixed disk 40 has a ring shape, and five protrusions 40a that fit into the grooves 35e of the first cylindrical portion 35a of the center bracket 35 are formed on the inner circumference. Therefore, the fixed disc 40 is movable in the axial direction with respect to the center bracket 35 and is not rotatable in the rotation direction. Further, the fixed disc 40 has the same outer circumference as that of the second friction plate 38.

The disc spring 41 has the first cylindrical portion of the center bracket 35 on the inner circumference.
It has a truncated cone shape in which a hole 41a to be inserted into the outer periphery of 35a is formed.

The circlip 42 is the first cylindrical portion of the center bracket 35.
It is inserted into the thread groove 35f of 35a.

The stainless steel disc 43 is the disc part of the center bracket 35.
The hole 43a of the disc 43 is fixed to the punched-out portion 35d of the disc portion 35b of the center bracket 35 by press fitting or the like while abutting against the 35b.

Then, the stainless disk 43 and the first friction plate 37 are brought into contact with the planetary gear speed reduction mechanism side of the disk portion 35b of the center bracket 35, and then the rotating disk 39 and the second friction plate 38 are arranged. To do. Then, the protrusion 39a of the rotary disk 39 is fitted into the groove 35e of the first cylindrical portion 35a and brought into contact with the second friction plate 38. Further, after passing the hole 41a of the disc spring 41 through the outer periphery of the first cylindrical portion 35a, the outer peripheral end of the disc spring 41 is brought into contact with the fixed disk 40. Then, the washer 42 is fitted into the thread groove 35f of the first cylindrical portion 35a, the disc spring 41 is bent, and the disc spring 4
A washer (42) is brought into contact with the inner peripheral end of (1) to restrict the movement of the disc spring (41) in the axial direction.

Therefore, due to the spring force of the disc spring 41, the fixed disc
The first friction plate 37 is pressed against the disc portion 35b of the center bracket 35 via the 40, the second friction plate 38, and the rotary disc 39.

Then, on the outer periphery of the first cylindrical portion 35a of the center bracket 35, the first friction plate 37 and the rotary disc 37 are provided by the disc spring 41.
39, the second friction plate 39, and the fixed disk 40 are integrally held. The first friction plate 37, the rotary disc 39, the second friction plate 38, the fixed disc 40, and the disc spring 41 constitute a shock absorber. And washer 44, circlip 45
This restricts the movement of the center bracket 35 in the axial direction. A thrust washer 47 is inserted between the end surface of the first cylindrical portion 35a of the center bracket 35 and the protruding portion 13 of the drive shaft 12. Further, when fixing the housing 15 and the end frame 7 with the through bolt 46, both ends of the second cylindrical portion 35c of the center bracket 35 are sandwiched between the housing 15 and the yoke 3 to fix the center bracket 35. Together with the wave washer 36,
The internal gear 32 is also the disk portion 35b of the center bracket 35.
And the first step portion 3a of the yoke 3 are sandwiched and fixed.

Next, the operation of the above configuration will be described. When the magnet switch 2 is activated, the plunger 25 is attracted and the lever 24 engaged with the joint portion 25a is pulled toward the magnet switch 2 side. This rotation of the lever 24 advances the pinion 22 via the spline tube 20 and the one-way clutch 21. Then, when the pinion 22 is brought into contact with the ring gear 23, the contact of the magnet switch 2 is closed, and a current is passed through the exciting coil 4a of the starter motor 1. Further, the armature shaft 5 is rotated by the exciting magnetic flux of the exciting coil 4a.

Then, the rotation of the armature 5 is transmitted to the planetary gear 30 via the sun gear 10 of the armature shaft 6. Further, the internal gear 32 is prevented from rotating by the disc spring 41 by the rotating disc 39 pressed against the disc portion 35b of the center bracket 35 when the rotational torque is equal to or less than a predetermined rotational torque. Therefore, the rotation of the armature shaft 6 is decelerated and transmitted to the drive shaft 12 by the planetary gear 30 meshing between the sun gear 10 and the teeth 32a of the internal gear 32. Then, the reduced rotation is transmitted to the pinion 22 via the spline tube 20 and the one-way clutch 21. Further, the rotation of the pinion 22 is transmitted to the ring gear 23 to start the internal combustion engine.

The above configuration has the following effects.

(A) When the pinion 22 meshes with the ring gear 23, when a predetermined torque or more is applied (for example, when the pinion 22 is rotating, the ring gear 23 is meshed again with the ring gear 23 again, or the like, an overload occurs). First friction plate 37 by spring 41
And the disk portion 35b of the center bracket 35, or the first
The rotation disc 39 prevents the rotation between the rotation disc 39, the second friction plate 38 and the rotation disc 39, or the second friction plate 38 and the fixed disc 40. The internal gear 32 that was being turned rotates. Then, a torque equal to or higher than a predetermined torque is applied to the pinion from the armature 5.
It is possible to prevent it from joining the rotation transmission path up to 22.

(B) The shock absorber is well arranged by utilizing the space around the outer periphery of the first cylindrical portion 35a of the center bracket 35 that pivotally supports the drive shaft 12, so that the starter does not have to be enlarged in the axial direction. , A shock absorber can be attached.

(C) Since the shock absorber is unitized on the outer circumference of the first cylindrical portion 35a of the center bracket 35 and arranged on the outer circumference of the drive shaft 12, the slip torque of the shock absorber is set before being mounted inside the starter. can do. In other words, as a method of measuring the slip torque, the center bracket
With 35 fixed, a cylindrical ring having a shape similar to that of the internal gear 32 and having a notch that fits into the protruding portion 39a of the rotating disk 39 is applied with a force in the rotational direction to generate a sliding torque. To measure.

(D) Since the shock absorber is arranged on the pinion 22 side of the planetary gear speed reduction mechanism, there is an advantage that it is less susceptible to the heat of the starter motor 1.

(E) By the second cylindrical portion 35c, it is possible to prevent water from entering the first and second friction plates 37 and 38 of the shock absorber through an opening or the like where the pinion 22 of the housing 15 and the ring gear 23 mesh with each other. Water is attached to the first and second friction plates 37 and 38,
It is possible to prevent the friction coefficient between the friction plate 37 and the center bracket 35 of the vehicle from decreasing and the transmission torque to decrease, which makes it impossible to transmit the driving force of the starter motor 1. Water adheres to the first and second friction plates 37 and 38,
It is possible to prevent the first and second friction plates 37, 38 from being rusted, increasing the friction coefficient, increasing the impact torque, and breaking the rotation transmission path.

(F) The wave washer 36 is arranged in the concave portion 35g of the disk portion 35b of the center bracket 35, and the concave portion 35g can store the water transmitted inside the second cylindrical portion 35c.

(G) Even if the lubricating grease stored in the planetary gear speed reduction mechanism scatters, the protrusion 32c prevents the grease from entering the shock absorber. Then, it is possible to prevent that the grease is attached to the first and second friction plates 37 and 38, the slip torque of the shock absorber is reduced, and the drive force of the starter motor 1 is not transmitted to the pinion 22.

(H) Internal gear 32 on the outer periphery of internal gear 32
The center gear 35 has a predetermined gap between the second cylindrical portion 35c and the second concave portion 32d to absorb the elastic deformation of resin or the like, and the internal gear 32
Elastic deformation of the inner gear 32 and the second
Internal gear 32 due to contact with the tubular portion 35c of
Can be prevented from rotating.

Next, referring to FIG. 3 to FIG. 5, the second to fourth embodiments of the starter with the planetary gear speed reduction mechanism of the present invention will be described.
In each embodiment, the same reference numerals as those in FIG. 1 denote the same parts.

First, in the second embodiment, the internal gear 50 is
A first gear part 50a meshing with the planetary gear 30, a connecting part 50b having an L-shaped cross section along the outer periphery of the projecting part 13 of the drive shaft 12 with a slight clearance, and an intermediate bracket at one end of this connecting part 50b. A cylindrical portion 50d in which a second gear portion 50c is formed on the outer periphery of the first cylindrical portion 35a of the 35 with a slight gap therebetween.
Composed of and.

The first and second friction plates 51, 52 are disc-shaped, and are in contact with the cylindrical portion 35b and the inner circumference of the second cylindrical portion 35c by the punched-out portion 35d of the intermediate bracket 35.

The rotary disk 53 is sandwiched between the first and second friction plates 51 and 52, and the inner peripheral end surface 53a is meshed with the second gear portion 50c of the internal gear 50.

Further, the disc spring 54 uses the washer 55 fixed to the inner circumference of the second cylindrical portion 35c (screw tightening, etc.) to move the first and second friction plates 51, 52 and the rotary disc 53 to the circle of the intermediate bracket 35. It is pressed against the plate portion 35b.

The washer 56 is inserted between the disk portion 35b of the intermediate bracket 35 and the end surface of the tubular portion 50d of the internal gear 50, and receives a thrust.

In the first embodiment, as described above, similarly, when an excessive impact torque is applied, the rotary disk 53 rotates and the internal gear 50 rotates to absorb the impact.

Also in the second embodiment, the shock absorber can be arranged by utilizing the space on the outer circumference of the first cylindrical portion 35a of the intermediate bracket 35.

In the third embodiment shown in FIG. 4, the internal gear 60 includes a gear portion 60a that meshes with the planetary gear 30, and the drive shaft 12
A blocking portion 60b that faces the outer periphery of the protruding portion 13 of the intermediate bracket 35 with a slight gap, and a tip of the blocking portion 60b that faces the outer periphery of the first cylindrical portion 35a of the intermediate bracket 35 with a slight gap, Accordingly, the intermediate bracket 35 includes a protrusion 60c extending to the disc portion 35b of the intermediate bracket 35.

61 and 62 are first and second friction plates, and the rotary disc 63 is provided between the first and second friction plates 61 and 62, and the internal gear 6
A hole 63a into which the zero protrusion 60c is inserted is formed.

Reference numeral 67 denotes a fixed disk, which is spline-coupled to a groove portion 35g extending in the axial direction on the inner periphery of the second cylindrical portion 35c of the intermediate bracket 35.

64 is a disc spring, the washer 65 is fixed to the inner circumference of the second cylindrical portion 35c, and the disc spring 64 causes the disc portion 35b of the intermediate bracket 35 to face the first and second friction plates 61, 62, rotating disk
63, the fixed disk 67 is pressed.

A wave washer 66 is inserted between the washer 65 and the internal gear 60.

In the fourth embodiment shown in FIG. 5, the internal gear
Reference numeral 70 denotes a first gear portion 70a that meshes with the planetary gear 30, a disk portion 35b side of the intermediate bracket 35, and a second gear portion 7 on the outer circumference.
And a cylindrical portion 70c in which 0b is formed.

For assembly, the inner peripheral end of the disc spring 74 is brought into contact with the disc portion 35b of the intermediate bracket 35. Next, the intermediate bracket 3
5, the first fixed disk 76 and the first friction plate spline-coupled to the axial groove 35g provided on the inner circumference of the second cylindrical portion 35c.
71, a rotary disk 73 that meshes with the second gear portion 70b of the internal gear 70, a second friction plate 72, and a second fixed disk 77 that is splined to the groove 35g. After that, the washer 75 is inserted and fixed while bending the disc spring 74 to obtain a predetermined torque.

Then, the disc spring 74 includes the first and second fixed disks 76, 77,
The first and second friction plates 71 and 72, the rotary disc 73, and the washer 7
Pressed to the 5 side.

Instead of the disc spring, another elastic body (eg, spring, rubber, etc.) may be used.

Further, although the outer periphery of the drive shaft 12 is pivotally supported by the intermediate bracket or the internal gear, the outer periphery of the armature shaft 6 may be pivotally supported.

[Brief description of drawings]

FIG. 1 is a partial sectional front view showing a first embodiment of a starter with a planetary gear speed reduction mechanism according to the present invention, FIG. 2 is a partial sectional front view showing an essential part of FIG. 1, and FIGS. It is a partial cross-sectional front view which shows the principal part of 2nd Embodiment of the starter with a planetary gear speed reduction mechanism of this invention. 1 ... Starter motor, 3 ... Yoke, 6 ... Armature shaft, 10 ... Sun gear, 12 ... Drive shaft, 13 ...
… Projection part, 22 …… Pinion, 23 …… Ring gear, 30 …… Planet gear, 32 …… Internal gear, 35 …… Center bracket, 35a …… First cylindrical part, 35b …… Disc part, 39 ...... Rotating disk, 41 …… Disc springs that form springs.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazunori Kato 1-1, Showa-cho, Kariya, Aichi Nihon Denso Co., Ltd. (72) Inventor Kazuo Hirama 1-1, Showa-cho, Kariya, Aichi Nidec Within the corporation (56) References JP 61-46464 (JP, A) Actual development 58-132171 (JP, U) Actual development 58-70462 (JP, U) Actual development 54-106436 (JP, U)

Claims (2)

[Claims] 1. A drive shaft having an armature shaft for a starter motor, a drive shaft arranged on the same axis as this armature shaft, and projecting radially outward from an end of the armature shaft, and a drive shaft of the drive shaft. A pinion that is helically spline-coupled to the outer periphery and meshes with the ring gear of the internal combustion engine, a sun gear that is formed on the outer periphery of the armature shaft of the starter motor, and a planetary gear that meshes with this sun gear and that is provided on the protrusion of the drive shaft. A planet that has an internal gear that is meshed with a planetary gear and that is arranged on the fixed side, and that reduces the rotation of the armature shaft and transmits it to the drive shaft via the sun gear, the planetary gear, and the internal gear. A gear reduction mechanism, the drive shaft and the The drive shaft or the armature shaft is rotatably supported by having a cylindrical portion arranged on one of the outer circumferences of the armature shaft via a bearing and a disc portion extending from the end of the cylindrical portion in the outer diameter direction. A center bracket, a rotary disc that is arranged so as not to be rotatable in the circumferential direction with respect to the internal gear, and is arranged on the outer periphery of the cylindrical portion of the center bracket, and the rotary disc is a disc portion of the center bracket or A spring that is arranged so as not to rotate in the circumferential direction with respect to the disk portion and is pressed against a fixed disk arranged on the outer circumference of the cylindrical portion of the center bracket, and is arranged on the outer circumference of the cylindrical portion of the center bracket. A shock absorber having the rotating disk and fixing means for holding the spring on the outer periphery of the cylindrical portion of the center bracket; Starter with a planetary gear reduction mechanism comprising a pressing means for pressing the internal gear in the axial direction. 2. A drive shaft having an armature shaft of a starter motor, a drive shaft arranged on the same axis as this armature shaft, and projecting radially outward from an end of the armature shaft, and a drive shaft of the drive shaft. A pinion that is helically spline-coupled to the outer periphery and that meshes with a link gear of an internal combustion engine, a sun gear that is formed on the outer periphery of the armature shaft of the starter motor, and a planetary gear that meshes with the sun gear and that is provided on a protruding portion of the drive shaft. It has an internal gear that is meshed with this planetary gear and arranged on the fixed side, and reduces the rotation of the armature shaft and transmits it to the drive shaft via the sun gear, the planetary gear and the internal gear. A planetary gear reduction mechanism, the drive shaft and the The drive shaft or the armature shaft is rotatably supported by having a cylindrical portion arranged on one of the outer circumferences of the armature shaft via a bearing and a disc portion extending from the end of the cylindrical portion in the outer diameter direction. A center bracket, a rotary disc that is arranged so as not to be rotatable in the circumferential direction with respect to the internal gear, and is arranged on the outer periphery of the cylindrical portion of the center bracket, and the rotary disc is a disc portion of the center bracket or A spring that is arranged so as not to rotate in the circumferential direction with respect to the disk portion and is pressed against a fixed disk arranged on the outer circumference of the cylindrical portion of the center bracket, and is arranged on the outer circumference of the cylindrical portion of the center bracket. A shock absorber having the rotating disk and fixing means for holding the spring on the outer periphery of the cylindrical portion of the center bracket; A hole which is arranged between the planetary gear speed reduction mechanism and the center bracket and the armature of the starter motor, penetrates the armature shaft, and faces the outer periphery of the armature shaft via a minute gap, and the planet from the hole. A starter with a planetary gear speed reduction mechanism, comprising: a gear speed reduction mechanism and a cylindrical portion extending toward the center bracket side; and a partition wall having a circular disk portion continuously extending in the outer diameter direction of the cylindrical portion.