JP2002156009A - Epicyclic reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epicyclic reduction gear capable of improving reliability as an epicyclic reduction gear, reducing parts and processes in number and adapting to microminiaturization. SOLUTION: The epicyclic reduction gear 1 is characterized in that a planetary carrier 3, one of parts supporting a planet gear 4 constituting a planetary mechanism, has an integrated projecting shape formed by plastic deformation of pressed metal material and a projecting part 6 is rotatably journaled to the planet gear 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a planetary gear reducer,
And the structure of a planet carrier constituting the planetary gear mechanism,
And a processing method.

[0002]

2. Description of the Related Art For example, in a zoom lens driving mechanism of a professional video camera or a medium insertion / output driving device part such as an OA peripheral device in an office, the shaft rotation output of a motor (small motor) as a power source is controlled to a desired rotation. There are many cases where it is necessary to decelerate and transmit to the area.

To meet such demands, a speed reduction ratio using a planetary gear mechanism has been used since a relatively large speed ratio can be obtained with a small size and light weight. In this planetary gear reduction device, a single-stage reduction by a single planetary gear may not provide a sufficient reduction ratio, and in such a case, it is used as a multi-stage planetary gear reduction device.

As this multi-stage planetary gear reducer, for example, a three-stage planetary gear reducer 10 as shown in FIG.
There is mainly a cylindrical housing case 2 with an internal gear.
, A planetary gear (planet gear) 4, and a sun gear (sun gear) 5. When a drive motor body (not shown) is connected to the internal gear housing case 2 on the opposite side of the output shaft 7 and is attached, the pinion 11 fixed to the rotating shaft of the motor meshes with the planetary gear 4a. The planetary gear 4a is supported by a planetary carrier 13a via a pin 12 which is a central axis of rotation of the planetary gear 4a. This is a rotating structure (see FIG. 2B).

[0005] The planetary carrier 13a has a planetary gear 4
A fitting hole for inserting the pin 12 which is the central axis of the hole a is provided, and the pin 12 is fixed to the planet carrier 13a by press-fitting the pin 12 into the fitting hole. As a result, the planetary gear 4a having the pin 12 as a central axis is also supported by the planet carrier 13a.

The planetary gear 4a is connected to the pin 1 in the same manner as described above.
Two are rotatably mounted on one side of the planet carrier 3a through the two. Here, these three planetary gears 4a
And a planetary carrier 13a supporting the planetary gear 4a
And the sun gear 5a located on the central axis of the planet carrier 13a are referred to as a planetary gear unit Y1. The sun gear 5a of the planetary gear unit Y1 is located on the opposite side of the planetary carrier 13a with respect to the planetary gear 4a, and is connected to the planetary gear 4b of the next stage planetary gear unit Y2.

That is, the three-stage planetary gear reducer 10 sequentially inputs its input from the motor rotation shaft (pinion 11) to the planetary gear 4a, the pin 12, the planet carrier 13a, the sun gear 5a,
Power is sequentially transmitted to the planetary gears 4b, the pins 12, the planetary carriers 13b,..., And the planetary carrier 13c of the final stage planetary gear unit Y3 transmits the final reduced output to the output shaft 7.

[0008]

The planetary gear reducer constructed as described above has a structure in which each planetary gear rotates about a pin as a central axis and is supported by a carrier via the pin. Therefore, the position and the verticality of the pin serving as the center axis of the planetary gear when attached to the planetary carrier are important. However, as described above, the step of attaching the pin to the planetary carrier involves press-fitting the pin into the fitting hole of the carrier, and at the time of press-fitting, the pin is bent or the pin is crushed. . Further, the pins and the planet carrier may be scraped or bent at the time of press-fitting, which may cause problems such as a decrease in yield, unevenness in rotational torque and abnormal noise.

In the process of press-fitting a pin having such a small size, it is difficult to secure the accuracy and strength of the position and verticality of the pin, which leads to a decrease in the reliability of the planetary gear reducer. Would. Further, the step of press-fitting the pin is also a problem with respect to miniaturization of the planetary gear reducer. Further, when assembling the planetary gear reducer, the fact that the planet carrier and the pin are separate bodies increases the number of parts, and accordingly, the number of manufacturing steps is increased, which is troublesome.

Therefore, the present invention improves the reliability of a planetary gear reducer, further reduces the number of parts and the number of steps, and is applicable to ultra-miniaturization. It is an object to provide a machine.

[0011]

SUMMARY OF THE INVENTION In order to solve these problems, the present invention relates to a planetary gear mechanism using a planetary gear mechanism. The carrier has an integral projection shape by plastic deformation of a metal material by press working, and
The present invention provides a planetary gear reducer, wherein the planetary gear is pivotally supported via the projection.

That is, according to the present invention, since the projection as the central axis of each planetary gear is integrally formed on one side of the planetary carrier, the step of individually press-fitting the pins into the planetary carrier is not required. For this reason, the reliability of assembly as a planetary gear reducer can be improved, and the number of parts and the number of steps can be reduced.

In addition, it is preferable in terms of quality that the planetary carrier is integrally formed by press working, and the use of press forming improves the precision of parts and sufficiently copes with an ultra-small planetary gear reducer. It becomes possible.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a planetary gear reducer according to the present invention will be described by taking a four-stage planetary gear reducer as an example.
This will be described with reference to FIG. Note that the planetary gear reducer according to the present invention is not limited to the present embodiment.

In the four-stage planetary gear reducer 1 according to the present invention, a planetary gear unit Y composed of a planetary gear 4, a planet carrier 3, and a sun gear 5 is coaxially arranged in a cylindrical internal gear housing case 2. There are four sets in a row,
It forms the structure of a basic multi-stage planetary gear reducer.

The first stage disk-shaped planet carrier 3a
Are formed at three places on the plate with a distribution of 120 degrees, and each one of the protrusions 6 becomes a central axis of the planetary gear 4a.
Here, the projection 6 is formed in advance so as to be a vertical projection with respect to the central axis position of each planetary gear 4a and the plane on the plate of the planetary carrier 3a when the planetary gear unit Y1 is formed. . When the respective planetary gears 4a are mounted around the projection 6 formed as described above as a central axis, the planetary carrier 3a supports three planetary gears 4a.

That is, since the projections 6 are formed at positions corresponding to the conventional pins individually pressed into the planetary carrier, it is only necessary to mount the planetary gear 4a on each projection 6. The planetary gear unit Y1 can be formed. Further, since the protrusion 6 is integrally formed so as to protrude vertically from the planet carrier 3a, it is not necessary to confirm the degree of verticality at the time of press-fitting the pin as in the related art.

The planetary carrier 3a to which the planetary gear 4a is mounted has a sun gear 5 at a center position on the opposite side of the planetary gear 4a.
a is press-fitted, and the planetary gear units Y1, Y2, Y
Form 3 Further, a planetary gear unit Y4 into which the output shaft 7 is press-fitted instead of the sun gear is formed.

The planetary gear units Y1, Y2, Y3
When the Y4 stages are incorporated and a drive motor is mounted on the end cap 14 side, a pinion fixed to the rotating shaft of the motor (omitted because it is the same as the conventional example)
The sun gear 5a of the planetary gear unit Y1 is engaged with the planetary gear 4b of the next stage planetary gear unit Y2. Thus, the planetary gear reducer transmits its input from the motor rotation shaft to the four-stage planetary gear units Y1, Y2, Y3, and Y4, and transmits the final reduction output to the output shaft 7.

In the planetary gear reducer of the present invention, the number of parts is reduced because the projection is integrally formed with the planetary carrier, and the manufacturing process is simplified because the step of press-fitting the pin is eliminated. . Further, since the step of press-fitting the pin is eliminated, the pin is not bent, crushed, or scraped at the time of press-fitting of the pin, so that the quality and the yield are improved, and no problem such as abnormal noise is caused. As a result, the reliability as the planetary gear reducer is improved.

Further, the planet carrier constituting the planetary gear reducer according to the present invention can be mass-produced by press molding. This press molding is, specifically,
It is composed of blanking, stamping, hole punching, and outline punching processes. The planetary carrier of the present invention is usually formed by nitriding and polishing in addition to press molding by a press.

Hereinafter, a method of processing the planetary carrier including the pressing will be described in detail. As the metal material of the planet carrier, a copper-based or iron-based plate material used for normal pressing, for example, a cold-rolled steel plate or the like can be used. A plate-shaped blank 20 is formed using these materials (blank processing). As shown in FIGS. 3A and 3B, this blank 20 is used as a planet carrier mold.
A sandwiching pressure is applied between the lower mold 22 having the recess 24 and the upper mold 21. At this time, the protrusion 6 serving as the center axis of the planetary gear is formed on the blank 20 corresponding to the recess 24 of the lower die 22 (coining). Here, the concave portion 2 of the lower die 22
Numeral 4 is provided so as to be accurately perpendicular to the plane on the plate of the molded planet carrier.

An insertion hole 23 for inserting a sun gear is formed in the blank 20 on which the projection 6 is formed (hole punching). Further, the blank 20 in which the projection 6 and the insertion hole 23 are formed is die-cut to the outer dimensions of the planet carrier (outer punching). A series of workings here is cold working (see FIG. 4).
reference). Through the above steps, the appearance as a planet carrier is formed.

Further, the planetary carrier is subjected to a nitriding treatment to increase hardness and corrosion resistance, and then polished to remove burrs and the like, thereby completing the processing of the planetary carrier. Here, as the nitriding method, either gas nitriding using ammonia or liquid nitriding using cyanide or the like can be used. The polishing method is not particularly limited, but includes, for example, barrel polishing.

As described above, since the projection of the planet carrier of the present invention becomes the center axis of the planetary gear, the verticality and the installation position are important. Here, in the case of manufacturing a planetary gear reducer having a module of 0.2 or more, there is no particular problem in forming a planetary carrier used for it by metal injection molding or sintering. However, when the module size is 0.2 or less, it is difficult to form a projection with high precision by metal injection molding or sintering in order to form a planet carrier as in the present invention. Therefore, by using the press working shown in the present invention, it is possible to cope with downsizing of the planetary gear, and it is possible to form a planet carrier with high accuracy, practicality and good mass productivity. Becomes

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The working procedure of the planetary carrier part of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist. .

As a metal material to be pressed, SPCE is used as a cold-rolled steel sheet, and a plate material having an outer diameter of about φ3 mm and a thickness of about 0.6 mm is prepared as a primary work blank. Next, the primary work blank is sandwiched between an upper die 21 and a lower die 22 of a press working press forming machine as shown in FIG. 3, and a pressure of about 14 t / mm ² is applied (coining work). By this coining, blank 2
No. 0 is plastically deformed to have a thickness of 0.5 mm and a height of the protrusion 6 of 0.7 mm.

Next, the secondary blank machined in the shape of the disk-shaped planetary carrier prototype has a point located at the center of the disk.
An insertion hole with a diameter of 0.8 mm is formed by punching. Further, after the insertion hole is formed, the outer periphery is cut off in a circular shape having a diameter of 2.78 mm with the insertion hole as a reference center by outer shape punching, and the die is removed.

The planetary carrier thus formed was subjected to nitriding by tuftride treatment, and thereafter, barrel polishing was performed to finish the outer surface of the planetary carrier, thereby producing a planetary carrier 3.
When this planetary carrier 3 was incorporated into the planetary gear reducer shown in FIG. 1, a highly reliable planetary gear reducer free from uneven rotation torque and abnormal noise was obtained.

[0030]

As described above, the planetary gear reducer according to the present invention has a projection formed integrally with the planetary carrier by press working, which eliminates the conventional step of press-fitting the pin. It is possible to eliminate problems such as bending, crushing of the pin, reduction in yield due to warpage of the planet carrier, uneven rotation torque, and abnormal noise caused by press-fitting. Thereby, the reliability as a planetary gear reducer is improved.

In addition, the number of parts can be reduced in the entire manufacturing process, and the number of processing steps is accordingly reduced, so that the assembly process can be simplified. Further, by manufacturing the planet carrier by press working, the technology of the present invention can be applied to a very small planetary gear reducer.

[Brief description of the drawings]

FIG. 1 is a sectional structural view of a four-stage planetary gear type speed reducer according to the present invention.

FIGS. 2A and 2B show a conventional three-stage planetary gear type speed reducer, in which FIG. 2A is a sectional structural view, and FIG. 2B is a view taken along the line AA in FIG.

3A and 3B are conceptual diagrams illustrating coining, in which FIG. 3A is before coining, and FIG. 3B is after coining.

4A and 4B show a planetary carrier of the present invention, wherein FIG. 4A is a front view and FIG. 4B is a sectional view.

[Explanation of symbols]

 1 4 stage planetary gear reduction device 2 ... internal gear housing case 3, 3a, 3b, 3c ... planet carrier 4, 4a, 4b, 4c ... planetary gear 5, 5a, 5b, 5c ..Sun gear 6 ... Protrusion 7 ... Output shaft 10 ... Three-stage planetary gear reducer 11 ... Pinion 12 ... Pin 13, 13a, 13b, 13c ... Planetary carrier 14 ..End cap 20 ... Blank 21 ... Upper mold 22 ... Lower mold 23 ... Insertion hole Y1, Y2, Y3, Y4 ... Planetary gear unit

Claims (1)

[Claims] In a gear reducer using a planetary gear mechanism, a planetary carrier, which is one of parts supporting a planetary gear constituting the planetary mechanism, is formed as an integral type formed by plastic deformation of a metal material by press working. A planetary gear reducer having a projection shape, wherein the projection is configured to rotatably support the planetary gear.