JPS6231739A - Planetary gear device - Google Patents

Abstract

PURPOSE:To reduce the axial dimensions of a planetary gear device and to enhance the mechanical strength thereof, by making the front end face of a support pin on a planetary gear abut against a stepped part in an attaching hole, and by plastically deforming the outer periphery of the pin. CONSTITUTION:Three support pins are stationarily planted on one side of a planetary arm 13 at equal intervals, and are journalled thereon with planetary gears 10, respectively. The front end of each support pin 11 is formed therein with a plurality of circular grooves 26 in the outer peripheral part of the support pin 11, and is fitted into the associated planetary gear 10 such that the front end face 11a of the support pin 11 is made to abut against a stepped part 28 which is defined by an attaching hole 27 and a hole 27 having a diameter smaller than the outer diameter of the support pin 11. The materials of the planetary gear 13 is locally and plastically deformed into the circular grooves 26, and therefore, the support pin 11 is plastically coupled to the gear 4 due to a binding force effected around the circular grooves 26, and the coupling force between the support pin and the planetary gear may be held by a shearing force.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a planetary gear device. Starting for internal combustion engines
The present invention relates to a planetary gear device having a structure suitable for electric motors and the like.

[Background of the invention]

The conventional planetary gear device II of the planetary reduction mechanism is disclosed in Japanese Patent Application Laid-Open No. 57-
As disclosed in FIG. 1 of Japanese Patent No. 69140, a structure in which a support pin for pivotally supporting a plurality of planetary gears is press-fitted into a mounting hole provided in a planetary arm and fixed is widely used. Although this structure is known as a simple structure, if radial stress is repeatedly applied to the support pins due to the uneven pitch circles of the support pins, the support pins may If the pressing force is insufficient, the support pin may loosen or come out, which may prevent the planetary gear from properly meshing.

For this reason, it is common to make the length of the press-fitted part of the support pin longer than necessary, which has the disadvantage of increasing the axial dimension of the idling gear device.

On the other hand, in order to shorten the shaft length, it is possible to form the planet arm and support pin together by cold forging, but as a general rule, cold-open forming materials are limited to materials with a low carbon content. Therefore, in order to increase the mechanical strength, heat treatment such as carburizing and quenching must be performed, making it difficult to obtain a high-precision planetary gear device.Furthermore, injection molding and powder molding are also considered, but since it is hot molding, accuracy may be reduced due to thermal deformation. However, due to the material, it is difficult to obtain the same strength as that obtained with 4-steel materials.

[Purpose of the invention]

An object of the present invention is to provide a planetary gear device with a short axial dimension and high mechanical strength.

[Summary of the invention]

A gear device consists of a plurality of support pins implanted on the same circumference on one side of a planetary arm with an output shaft in the center, and a planetary gear supported by each of the support pins and meshing with an internal gear. The tip of the support pin is fitted into and abuts the stepped mounting hole, and is coupled with tension by the planetary arm material in the vicinity of the mounting hole, which is locally plastically deformed around the outer periphery of the pin. This provides a planetary gear device with short axial dimensions, high mechanical strength, and easy quality control.

[Embodiments of the invention]

A preferred implementation sequence of the drive device according to the invention will be explained with reference to the accompanying drawings.

FIG. 3 is a cross-sectional view of an embodiment of an internal combustion engine starting motor using the planetary gear system of the present invention. In the figure, a motor 1 has an armature 2 attached to a shaft 3, which is an input shaft, and a bearing 4,
It is rotatably supported within the rear cover 6 via the rear cover 5. An armature pinion 7, which is a central sun gear, is formed at one end of the shaft 3. There is a port 3 around the armature pinion 7.
An internal ring gear 8 is disposed coaxially with. In an annular space 9 formed by the armature pinion 7 and the internal ring gear 8, a plurality (for example, three) of planetary gears 10 are arranged at equal intervals. The planetary gear 10 is rotatably supported by a support pin 11 via, for example, a needle bearing, and meshes with an armature pinion 7 and an internal ring gear 8, respectively.

11 support pins, details of which will be explained later, especially pinion shaft 12
It is fixed to a swing arm 13 provided at one end. The pinion output shaft 12 is rotatably supported by a center bracket 16 and a gear case 17 via bearings 14 and 15, and a pinion 18 is disposed around the intermediate portion. Further, around the pinion shaft 12, there are provided a roller clutch 19 that transmits the rotation of the pinion output shaft 12 to the pinion 18, and a clutch sleeve 20 that moves the pinion 18 in the axial direction.

The shift lever 21 has a trap inside the gear case 17.

Magnetic switch 2 with one end fixed to gear case 17
2, and the other end is fitted into the groove 23 of the clutch sleeve 20. Further, the rear cover 6 and the yoke 25 disposed around the armature 2 are fixed via the gear case 17Kri and the fixing port 24.

Next, the planetary gear device will be explained in detail with reference to FIGS. 1 and 2. It is formed integrally with the output shaft 12 and is made of carbon steel (S45C).
Three support pins 11 made of so-called case hardened steel (80M41s) are implanted and fixed at equal intervals on one surface of the planetary arm 13 of the revolving portion, each supporting a planetary gear lO.

This support pin 11 has a plurality of circumferential grooves 26 on the outer periphery of the tip, and a stepped portion 28 formed by the mounting hole 27 of the planetary arm 13 and the hole 27 with a diameter smaller than that of the support pin 11 is formed on the tip surface of the support pin 11. 11a is inserted so as to be in contact with it. The material of the planetary arm 13 located on the outer periphery of the circumferential groove 26 is locally plastically deformed and flows into the circumferential groove 26, and is plastically bonded by the tension force generated on the circumferential paddle of the first circumferential groove 26. The bond is maintained.

That is, when the material of the planetary arm 13 around the support pin 11 is locally pressed from the axial direction by the mold, the material of the planetary arm 13, which is a soft material, is transferred to the circumferential groove of the support pin 11, which is the coupling surface. 26.

Locally plastically deformed by the circumferential protrusion in the circumferential groove,
They are combined by the high tension generated there. At this time, the end portion 11a of the support pin 11 is pressed and coupled to the step portion 28 of the through hole of the planetary arm 13.

According to this embodiment, since the tip of the support pin is in surface contact with the stepped portion of the planetary arm through hole, it is strong against radial stress.
In addition, since the support pin and the planetary arm are mechanically and firmly connected at the circumferential groove, the axial dimension 'i7 of the planetary arm can be shortened, resulting in a planetary gear device with a short oil length. In addition, since the hole in the planetary arm corresponding to the center portion of the support pin passes through, it is easy to measure the axial pulling force in the product strength test, which is effective for quality control. In addition, it can be used as a relief for the center part that remains after cutting when turning the support pin, and there is no need to finish machining both end faces, resulting in high productivity. Furthermore, the support pin can be freely selected from any hardness, and there is no need for heat treatment after joining, which makes it very durable, and the support pin and planetary arm can be assembled together at the same time as they are joined. It becomes a control device for dimensional accuracy.

In the above-mentioned embodiment, a plurality of circumferential grooves were provided on the outer periphery of the tip of the support pin, but it is also possible to separately prevent the support pin from being pulled out.

The rough surface is the first! , It goes without saying that it may also be used as a bonding surface.

〔Effect of the invention〕

As described above, according to the present invention, a planetary gear device having a short shaft length and high mechanical strength can be easily cleaned.

[Brief explanation of drawings]

Figure 1 shows the planet of the present invention! A vertical sectional front view of a part of the model car device. FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is a longitudinal sectional front view of a starter motor for an internal combustion engine using the planetary gear device of the present invention.

Claims (1)

[Claims] 1. A planetary arm having an output shaft at the center, a plurality of support pins implanted on the same circumference on one side of the planetary arm, and a planetary arm supported by each of the support pins. In a planetary gear device consisting of a planetary gear that meshes with an internal ring gear, the tip surface of the support pin is brought into contact with the stepped surface of the mounting hole passing through, and the outer periphery of the support pin is locally plastically deformed. A planetary gear device characterized by being firmly connected and fixed by surrounding materials. 2. The planetary gear device according to claim 1, wherein the support pin has a circumferential groove formed on the outer circumferential surface of the tip. 3. The planetary gear device according to claim 2, wherein the circumferential groove is a plurality of grooves.