JPS6090983A - Starter equipped with planetary reduction mechanism - Google Patents

Abstract

PURPOSE:To reduce the bearing loss, shorten the total length and permit to miniaturize the device by a method wherein a boss, integral with the shaft of a planetary gear, is projected to the side of an armature while the boss is supported to a center bracket through a bearing. CONSTITUTION:The boss section 6b, having L-shape in section, is secured integrally to the end 6a of the shaft 6 of the planetary gear 5 and the outer periphery thereof is supported to the center bracket 4, whose one part is arranged between the armature coil end 7a of the armature 7 and an armature shaft 1, through the bearing 2 while an output rotary shaft 3 is supported by a housing 10 and the center bracket 4 through bearings 3a, 2. Thus, the part supporting the boss section 6b of the center bracket 4 is located at the inside of the armature coil end 7a, therefore, the total length of the device may be shortened. On the other hand, the rotating speed of the boss section is lower than the rotating speed of the armature 1 after the planetary gear type speed reduction by a value corresponding to the reduction ratio thereof, therefore, the bearing loss due to the bearing 2 is small and the service life of the bearing 2 may be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a starter with a planetary reduction mechanism, and particularly to the structure of a center bearing portion.

[Prior art]

Conventionally, the center bracket structure of a starter with a planetary reduction mechanism has been supported by an armature shaft l via a bearing 2 as shown in FIG. 1, or supported by an output rotating shaft 3 as shown in FIG.
In this case, the supporting structure was supported through a bearing 2, or as shown in Japanese Utility Model Publication No. 5.3-24614, in which both of these supporting structures were combined.

However, as described above, when the armature shaft 1 is used to support the motor, it is supported at a portion that rotates at high speed before deceleration, so there are problems such as insufficient output due to bearing loss and an increase in the size of the motor. Furthermore, when supporting with the output rotating shaft 3, there was a drawback that the total length became long.

[Purpose of the invention]

In order to solve the above-mentioned drawbacks, the present invention has a boss part integral with the end of the shaft of the planetary gear that protrudes toward the armature side.
By supporting the outer periphery of this boss part on the center bracket via a bearing, there is less bearing loss after deceleration, and there is no increase in overall length, so the aim is to be more compact than conventional ones. shall be.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings.

3 and 4, the starter 2 with a planetary reduction mechanism generates an excessive bending moment on the output rotating shaft 3 when the binion lla connected to the one-way clutch 11 meshes with a ring gear (not shown). There is a problem in that force is concentrated on the connection between the output rotation shaft 3 and the armature shaft 1, and as a result, the rotation axis of the armature 7 shifts, causing interference between the armature 7 and the stator core 8a fixed to the yoke 8. A center bracket 4 is installed and supported.

The armature shaft 1 is supported by an end frame 9 and an output rotating shaft 3 via bearings 1a and 1b, and meshes with a planetary gear 5 rotatably mounted around a shaft 6 press-fitted into the output rotating shaft 3. Furthermore, a boss portion 6b having an angular cross section is integrally fixed to the end portion 6a of the shaft 6, and a portion of the outer periphery of the boss portion 6b is located between the armature coil end 7a of the armature 7 and the armature shaft l. The output rotating shaft 3 is supported by the disposed center bracket 4 through the bearing 2, and the output rotating shaft 3 is supported by the housing 1° and the center bracket 4 with the bearing 3a.

It is supported through 2. Further, a gap is formed between the inner circumference of the boss portion 6b and the shaft 1.

The planetary gear 5 meshes with an internal gear 12 of the center bracket 4 fixed to the yoke 8 and the housing 1o and a sun gear 15 formed on the armature shaft 1. The one-way clutch 11 is slidably assembled to the output rotating shaft 3 and rotatably engaged with the lever 13 . Reference numeral 14 denotes a magnetic switch that drives the lever 13 and cuts off and on the power supply to the motor.

In the above configuration, since the part that supports the boss portion 6b of the center bracket 4 is placed inside one armature coil end 7a, it is effective to shorten the overall length, and at the same time, the rotation speed after the planetary gear method reduces the rotational speed of the armature. Since the number is smaller by the reduction ratio, there is less bearing loss due to bearing 2.
Furthermore, the life of the bearing 2 can be ensured.

In the above embodiment, the boss portion 6b is integral with the end portion 6a of the shaft 6, but even if the boss portion 6b is directly connected to the output rotating shaft 3 through the space between the planetary gears 5, the same result can be obtained. effect can be obtained.

〔Effect of the invention〕

As described above, in the present invention, a part of the center bracket is arranged between the armature coil end and the armature shaft, and the boss part fixed to the output rotating shaft after deceleration via the planetary reduction mechanism is attached to the center bracket. Since the outer periphery of this boss part is supported by the center bracket through a bearing, the part of the center bracket that supports the boss part goes inside the armature coil end, reducing the overall length of the starter. As well as being able to
Since the boss portion supported by the center bracket is rotated at a reduced rotational speed, bearing loss due to bearings is reduced (and the life of the bearings can be extended, which is an excellent effect).

[Brief explanation of drawings]

FIGS. 1 and 2 are vertical cross-sectional views showing the configuration of the main parts of a conventional starter, FIG. 3 is a partial vertical cross-sectional front view showing an embodiment of the starter of the present invention, and FIG. 4 is a main part of the above embodiment. It is an enlarged longitudinal cross-sectional view. 1... Armature shaft, 2... Bearing, 3
...Output rotating shaft, 4...Center bracket, 5, 6
゜12.15... Planetary gear that constitutes the planetary reduction mechanism. Shaft, internal gear, sun gear, 6b...boss part. 7... Armature, 7a... Armature coil end. Representative Patent Attorney Takashi Okabe 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] (11) In a starter with a planetary reduction mechanism that reduces the rotation of the motor via a planetary reduction mechanism and transmits it to the output rotating shaft,
A part of the center bracket is disposed between the armature coil end and the armature shaft, a boss portion fixed to the output rotating shaft is made to protrude toward the inner circumference side of the center bracket, and the outer circumference of the boss portion is inserted through a bearing. A starter with a planetary reduction mechanism supported by the center bracket. (2) The boss portion is formed in a cross-sectional shape, and one end thereof is fixed to an end portion of a shaft that rotatably holds a planetary gear of the planetary reduction mechanism, and is connected to the output rotation shaft via this shaft. A starter with a planetary reduction mechanism according to claim 1, which is fixed.