JP2003172411A - Planetary gear reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively manufacture an input shaft on a reduction gear side in which a motor shaft is fitted, and also to fit the input shaft with high positional precision in a reduction gear completed by assembling a motor by a supplier or a user. <P>SOLUTION: In a planetary gear reduction gear, planetary gear mechanisms 11, 21 which have one step or more and transmits revolution movement of a plurality of planetary gears 15, 25 which circumscribe and mesh with sun gears 13, 23 rotated and driven around a central axis in a case 1 and inscribe and mesh with internal tooth gears 14, 24, etc., fixed to the case 1 to carriers 17, 27 through each planetary pin 16, 26 are internally mounted between an input shaft 4 and an output shaft 6 on the central axis. An air bleed channel 31 is formed at inner periphery in a fitting part of the motor shaft 8 of the input shaft 4. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small planetary gear reducer equipped with a planetary gear mechanism having one or more stages.

[0002]

2. Description of the Related Art Heretofore, this type of speed reducer has generally been used integrally by being connected to a motor, and a key system is widely adopted as an inexpensive method for connecting the speed reducer and the motor. However, in order to supply inexpensive motors, motor manufacturers are increasingly adopting straight shafts without a key groove on the motor shaft, and the degree of connection by the clamp system is increasing in correspondence with this straight shaft.

This clamp system is designed to be integrated with the motor shaft by fitting the motor shaft into the input shaft hole of the speed reducer and shrinking the slit portion provided at the end of the input shaft to maintain the accuracy. Therefore, there is no gap between the input shaft hole and the motor shaft, and air is compressed like the relationship between the cylinder and the piston, making it difficult to insert the air.

In order to prevent the air from being compressed, it is well known to make a drill hole for letting air escape from the inside of the input shaft hole to the outside thereof, but it is related to the design outside the input shaft. It is necessary to increase the number of processing steps such as drilling diagonally and to perform difficult processing.To solve this problem, the input shaft becomes longer, which causes the entire reducer to become longer. there were.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the motor shaft can be fitted into the input shaft hole in a precise and inexpensive manner without increasing the size of the small planetary gear reducer, particularly without increasing the size of the input shaft. The task is to facilitate.

[0006]

The small planetary gear reducer of the present invention is characterized in that an air vent groove is formed in the inner peripheral portion of the input shaft hole.

Further, the small planetary gear reducer of the present invention is characterized in that a groove for air bleeding is spirally formed in the inner peripheral portion of the input shaft hole.

[0008]

In the small planetary gear reducer according to claim 1,
By forming a groove in the inner peripheral portion of the input shaft hole, when the motor shaft is inserted, the air inside the input shaft hole can be easily inserted while coming out of the groove and the coaxiality can be maintained.

In the small planetary gear reducer of claim 2,
When the input shaft hole is manufactured by roughing with a lathe, a spiral groove is inevitably formed by machining a groove with a lead of about 30 mm / revolution and a depth of 0.25 to 0.5 mm. In the finishing process, burrs can be removed at the same time, and the production process can be completed in a short time because of the same process.

[0010]

FIG. 1 is a sectional view of a small planetary gear reducer showing a first embodiment of the present invention.

In FIG. 1, a case 1 is internally provided with two-stage planetary gear mechanisms 11 and 21, and a first-stage planetary gear mechanism 11 is provided.
In the case, the sun gear shaft 1 in which the input shaft 4 is supported via the bearing 5 on the central axis and is connected to the input shaft 4
2, the sun gear 13 is provided on the inner surface of the case 1, and the inner gear 14 is inserted along the inner circumference of the spigot portion 2a of the input-side case 2 and fixed to the inner circumference of the case 1 by a pin or a key. 15 are evenly arranged so as to externally mesh with the sun gear 13 and internally mesh with the internal gear 14, the planet pins 16 of each planet gear 15 are supported by the carrier 17, and the output side flange 17b of the carrier 17 has a first pin. The sun gear shaft 22 of the two-stage planetary gear mechanism 21 is connected on the central axis.

Next, in the second stage planetary gear mechanism 21,
The sun gear 23 is provided on the sun gear shaft 22 connected to the output side flange 17b of the first stage, and the internal gear 24 is inserted into the inner circumference of the case 1 along the inner circumference of the spigot portion 3a of the output side case 3. The plurality of planetary gears 25 are evenly arranged so as to externally mesh with the sun gear 23 and internally mesh with the internal gear 24, and the planet pins 26 of each planetary gear 25 have a carrier 27. The output shaft 6 is connected to the output side flange 27b of the carrier 27 on the central axis.

Incidentally, each planetary gear mechanism 11 to the case 1,
The interior of 21 is preferably carried out sequentially from the output side to the input side, and the case 1 and the motor flange 9 are connected and fixed at the same time by fitting the motor shaft 8 into the input shaft hole 7 of the input shaft 4. After that, by tightening the clamp bolt 33 of the input shaft 4 from the window provided in the case 1, the slit 34 provided in the input shaft 4 is contracted and the motor shaft 8 is clamped by the input shaft 4 on the central axis line. Are integrated into a small planetary gear reducer.

By the way, the input shaft hole 7 and the motor shaft 8
In order to ensure accuracy such as coaxiality, the fitting portion of is set to a size such that there is no gap between the inner diameter of the input shaft hole 7 and the outer diameter of the motor shaft 8. After closing the entrance, the air in the input shaft hole 7 has no place to go, and therefore it is difficult to fit the motor shaft 8. Therefore, by forming the groove 31 on the inner circumference of the input shaft hole 7, the air escapes and the fitting is not possible. It can be done smoothly, and the input shaft 4 and the motor shaft 8 can be easily integrated on the central axis.

3 and 4 are cross-sectional views of an input shaft portion of a planetary gear reducer according to a conventional example.

In FIG. 3, when a motor shaft (not shown) is fitted into the input shaft hole, conventionally, in order to facilitate this, a vent hole 42 is formed to allow air to escape from the inside to the outside of the input shaft hole. Was there.

The punched hole 42 can be formed by a drill or the like, but when manufacturing the input shaft, it must be processed in a process different from the process using a lathe, and the input shaft is held obliquely. Because of this, it took time to process and it was not possible to manufacture at low cost.

Further, the punched hole 43 in FIG. 4 is made to be perpendicular to the center line of the input shaft in order to make machining relatively easy.

However, the input shaft becomes long, and therefore the entire planetary speed reducer becomes large in size.

FIG. 2 is a sectional view of an input shaft showing a second embodiment of the present invention.

The groove formed in the input shaft hole in FIG. 2 is formed by forming a spiral groove 41 in addition to the linear groove 31 in FIG.

This is because the spiral groove is inevitably produced by making the groove of the lead about 30 mm / revolution and the depth of about 0.25 to 0.5 mm at the time of roughing on the lathe in manufacturing the input shaft. After the formation, the burrs can be removed at the same time in the finishing process, and the manufacturing process can be performed in an extremely short time because of the same process.

[0023]

As described above, the small planetary gear reducer according to the present invention does not increase the size of the input shaft and does not increase the size of the entire apparatus at the same time. It has become possible to easily and accurately mount various motors.

In addition, the small planetary gear reducer is not only provided with a motor attached thereto but also supplied with a form in which the motor prepared by the user can be attached. It became possible to assemble with high positional accuracy without requiring skill.

Furthermore, a motor shaft with a key groove can be mounted in the same manner as a straight shaft without using a key, and a wider range of small planetary gear reducers can be supplied.

The small planetary gear reducer according to the second aspect of the present invention has both the above effects and, at the same time, can be manufactured inexpensively and with high accuracy because the input shaft can be easily manufactured.

The present invention is not limited to the small planetary gear reducer, but can be applied to various gear reducers, friction type reducers not using gears, speed increasing gears, and the like.

[Brief description of drawings]

FIG. 1 is a sectional view of a small planetary gear reducer showing a first embodiment of the present invention.

FIG. 2 is a sectional view of an input shaft portion in a planetary gear reducer according to a conventional example.

FIG. 3 is a sectional view of another input shaft portion in the planetary gear reducer according to the conventional example.

FIG. 4 is a sectional view of an input shaft in a small planetary gear reducer showing a second embodiment of the present invention.

[Explanation of symbols]

1 case 2 Input side case 2a Inlay part 3 Output side case 3a Inlay part 4 input axes 5 bearings 6 Output shaft 7 Input shaft hole 8 motor axes 9 Motor flange 11 Planetary gear mechanism 13 sun gear 14 Internal gear 15 planetary gears 16 planet pins 17 career 21 Planetary gear mechanism 23 sun gear 24 Internal gear 25 planetary gears 26 planet pins 27 careers 31 groove 41 groove 42, 43 hole

Claims (2)

[Claims] 1. A revolving motion of a plurality of planetary gears, which are externally meshed with a sun gear rotatably driven on a central axis of the case and are internally meshed with internal gears fixed to the case, through carriers of respective planet pins. In a planetary gear speed reducer in which one or more stages of planetary gear mechanisms adapted to be transmitted to the interior are installed between the input shaft and the output shaft on the central axis, an air vent groove is provided in the inner periphery of the motor shaft fitting portion of the input shaft. A small planetary gear reducer characterized by being formed. 2. The small planetary gear reducer according to claim 1, wherein a spiral groove is formed on the inner circumference of the motor shaft fitting portion of the input shaft.