JPH07167225A - Small reduction gear - Google Patents

Abstract

PURPOSE:To stabilize planetary gears by incorporating axes into a holder body while flaring inlet parts of guide grooves when both ends of the axes of the planetary gears are fixed to the holder body. CONSTITUTION:Planetary gears 12 to revolute while rotating around a sun gear have planetary gear axes 15 on both ends of the planetary gears 12. A holder body 16 rotatably freely fixes the planetary gear axes 15 through guide grooves 17 of the holder body 16. The holer body 16 is an elastic member. The guide grooves 17 have grooves cut from outer circumference parts to the centers of the planetary gear axes 15, and groove diameters of the outer circumference parts are narrower than the planetary gear axes 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reduction gear mechanism for a small reduction gear directly connected to a small motor.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional small speed reducer using this type of planetary gear mechanism.

In FIG. 3, a motor shaft gear 33 is driven into a motor shaft 32 located at the center of a small motor 31. A lower case portion 34 is attached to the small-sized motor 31 by screw coupling with the motor shaft 32 as a central axis. The lower case portion 34 has two to four support shafts 35, and planet gears 36 are fitted into the support shafts 35, respectively. The planetary gears 36 are meshed with the peripheral shaft gear 33 on the inner circumference and the internal gear 37 is meshed on the outer circumference. An output shaft gear portion 39 is provided at the center of the internal gear 37. The intermediate pedestal 38 is connected to the lower case portion 39, serves as a bearing for the output shaft gear portion 39, and has a support shaft 35. The output shaft gear portion 39 meshes with the planetary gear 36, and the planetary gear 36 meshes with the internal gear 37. In this way, the gear in the center serves as the driving force, and the internal gear 37 is rotated through the planetary gear 36.
If it is a set, it has a mechanism of stacking this set in multiple stages when the reduction ratio is large. At the final stage of stacking this set, the output shaft 40 is located at the center of rotation of the internal gear 37.

[0004]

In the compact speed reducer using the planetary gear mechanism according to the conventional structure, the motor shaft gear 33 is meshed with the internal gear 37 via the planetary gear 36 to reduce the speed. A set of reduction ratios from the gear 33 to the internal gear 37 is small, and many sets of wheel trains are required to obtain a large reduction ratio. In this way, multiple gear parts are used to reduce the speed by combining multiple gears.
Therefore, there are problems that the cost is increased, the noise is large, and the backlash is large.

The present invention solves the above-mentioned conventional problems, and aims to reduce the number of parts and the cost, to be small and lightweight, to have a large reduction gear ratio and to have a small backlash. The purpose is to provide an inexpensive compact reducer with high transmission efficiency.

[0006]

A compact speed reducer according to the present invention comprises:
A sun gear that is directly connected to the motor shaft of a motor that rotates at high speed and that rotates coaxially with the motor shaft, a first gear that meshes with the sun gear, and a first gear that is directly connected to the first gear and has the same number of teeth and different diameters. A planetary gear that has two gears and revolves around the sun gear while rotating around the sun gear; and a fixed internal tooth that is meshed with the first gear of the planetary gear and is concentrically fixed to the motor shaft of the motor. A movable internal gear that meshes with a gear and a second gear of the planet gear and rotates concentrically with the motor shaft when the planet gear revolves, and is directly connected to the internal gear and coaxially with the motor shaft. And a planetary gear shaft at both ends, wherein the planetary gear shaft is loosely fitted into a holder body of an elastic member via a guide groove of the holder body. It is characterized by being done.

The guide groove is cut from the outer peripheral portion toward the center of the planetary gear shaft, and the outer peripheral portion is smaller in diameter than the planetary gear shaft.

The guide groove is characterized in that the groove is cut from the outer peripheral portion toward the center of the planetary gear shaft, and the groove depth of the outer peripheral portion is deep.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which a motor boss 2 and a motor shaft 3 are provided on a central axis of a small motor 1.
There is a sun gear 4 driven into the motor shaft 3. Motor shaft 3
As a component that takes the same central axis as the central axis of the sun gear 4,
Lower case member 6, fixed internal gear 10, holder body 16,
There are a movable internal gear 20 and an upper case member 25. The lower case member 6 guided and positioned by the motor boss 2 has a fixing screw 9
Is fastened to the motor 1. The fixed internal gear 10 is fixed to the lower case member 6 by the rotation stopping toothed portion 8. The rotation-stop tooth profile 8 has a tooth profile, and if the lower case member 6 side has a male tooth profile, the fixed internal gear 10 side has a female tooth profile and is fitted and fixed to each other.

The planetary gear 12 has a sun gear 4 in point symmetry 2 to 2.
Four of them are arranged and meshed with each other, and further mesh with the fixed internal gear 10 and the movable internal gear 20. The planetary gear 12 is held by the holder body 16 so that the central axis of the planetary gear 12 is always kept parallel to the central axis of the sun gear 4. The upper and lower shafts 15 of the planetary gear are accommodated in the planetary gear holding holes of the holder body 16 and supported at both ends. The holder body 16 is composed of a planetary gear guide groove 17 as a bearing portion of the planetary gear 12 and a column 18 for increasing torsional rigidity.

Hereinafter, the unit in which the planetary gear 12 is incorporated into the holder body 16 and fixed thereto will be referred to as a planetary gear unit. The planetary gear unit has a lower end supported by the holder support 7 and an upper end supported by both ends with the holder pressing portion 23 as a bearing, and rotates around the sun gear 4 as a central axis. In this planetary gear unit, since the planetary gear guide groove 17 is formed from the outer periphery of the holder body 16, the upper and lower shafts 15 of the planetary gear 12 are guided by the planetary gear guide groove 17 and are laterally incorporated. Therefore, here, it is not necessary to separate the holder body 16 into upper and lower bodies and press down the planetary gear 12,
The number of parts of the holding member is reduced and the assembling efficiency is improved.

Further, as shown in the plan view of FIG. 2, the planetary gear guide groove 17 of the holder body 16 is open toward the outer periphery in the first embodiment, but the first tooth profile of the gear of the planetary gear is formed. 13 and the second toothed portion 14 of the planetary gear are the toothed portion 11 of the fixed internal gear and the toothed portion 21 of the movable internal gear, respectively.
Therefore, the planetary gear 12 does not move outward due to the centrifugal force of rotation.

The movable internal gear 20 is made up of an outer peripheral portion 24 on the outer side of the internal tooth profile and an output shaft portion 22 at the center, and the lower outer peripheral portion 24 is the lower case portion village 6 and the output shaft portion at the upper end. Reference numeral 22 constitutes an upper case member 25 and a bearing portion supporting both ends thereof, and rotates about the central axis of the sun gear 4. The upper case member 25 has a hooking claw 26, which is hooked and fixed to the lower case member 6 by the hooking claw 26 and serves as a bearing for the output shaft portion 22 to cover the entire small reduction gear. ing.

The tooth profile of the planetary gear 12 is the first of the planetary gears.
And a second tooth profile 14 of the planetary gear. The first tooth profile 13 of the planetary gear is the tooth profile 5 of the sun gear of the tooth profile of the sun gear 4, and the fixed internal gear 1
It meshes with the tooth profile 11 of the fixed internal gear having the tooth profile 0. The second toothed portion 14 of the planetary gear is the movable internal gear 2
It meshes with the tooth profile 21 of the movable internal gear having a tooth profile of 0.

The first tooth profile 13 of the planetary gear and the second tooth profile 14 of the planetary gear have the same number of teeth Z, the modules are slightly different, and the tooth profiles are in phase.

Therefore, when the sun gear 4 rotates, the planetary gear 12 starts rotating and revolving because the fixed internal gear 10 does not work. The number of teeth of the fixed internal gear 10 is n, and the number of teeth of the movable internal gear 20 is n ± 1 to 4. Therefore, as the planetary gear 12 rotates and revolves, the fixed internal gear 1
0 and the tooth profile of the movable internal gear 20 are displaced. with this,
The movable internal gear 20 performs decelerated rotation. This can be expressed by the following formula.

[0017] In the above formula, the numbers 1 to 4 are used as integers having the same numerator and denominator.

In this way, the rotation of the sun gear 4 transmits the reduced rotation and the increased torque to the movable internal gear 20, and is output to the output shaft portion 22.

FIG. 2 shows a plan view of this embodiment. As shown in FIG. 2, the number of planetary gears is two, but theoretically it may be one, but from the balance of forces, two to four, and three is most desirable. However, from the above formula, the number of planetary gears is also limited by the reduction ratio.

As described above, since a wide reduction ratio is achieved by the meshing of a small number of gears, the reduction of the transmission efficiency due to the meshing is small, and the transmission efficiency from the input to the output is high. As a result, a large torque can be generated in the output shaft portion 22.

This means that the peripheral portion of the output shaft 22 must have strength to withstand a large torque, but this mechanism has a structure to withstand a large torque in principle. First,
When the output shaft torque is replaced by the tooth profile portion 21 of the movable internal gear, since the radius from the center is large, the force received by the tooth profile portion 21 is small. Further, there are a plurality of planetary gears 12. Further, the meshing ratio between the tooth profile portion 21 of the movable inner fungus gear and the second tooth profile portion 14 of the planetary gear is large. As described above, the load applied to one tooth of the toothed portion 21 of the movable internal gear, the second toothed portion 14 of the planetary gear, the first toothed portion 13 of the planetary gear, and the toothed portion 11 of the fixed internal gear is small, Good and as a result, high torque of the output shaft portion 22 is achieved.

Furthermore, since a high reduction ratio can be achieved with a combination of a small number of gears, the backlash is small, and the number of parts is small, so that the size reduction gear is low in cost.

Furthermore, the speed reduction mechanism has a lower case member 6
And because it is sealed by the upper case member 25, the noise is small,
It is a small reducer that does not easily get dust.

FIG. 4 shows a sectional view of a planetary gear unit portion according to another embodiment 2 of the present invention. Further, similarly, FIG. 5 shows a plan view of the planetary gear unit portion of the second embodiment. Here, a planetary gear guide groove 17 formed from the outer periphery of the holder body 16
Has a narrow entrance, and the upper and lower shafts 1 of the planetary gear 12
5 is installed laterally while expanding this portion in the plane direction and is firmly fixed in the planetary gear holding hole of the holder body 16. Therefore, the stability after the planetary gear 12 is incorporated in the holder body 16 is superior to that of the first embodiment. Such a structure is more effective if the material of the holder body 16 is elastic like plastic because the planetary gear 12 is press-fitted into the holder body 16.

FIG. 6 shows a sectional view of a planetary gear unit portion according to another embodiment 3 of the present invention. Similarly, FIG. 7 shows a plan view of the planetary gear unit portion of the third embodiment. Here, a planetary gear guide groove 17 formed from the outer periphery of the holder body 16
Are formed in the thickness direction of the holder body 16, the groove depth is 3/4 or less of the plate thickness of the holder body 16, and the groove width is larger than the shaft 15 of the planetary gear 12. The upper and lower shafts 15 of the planetary gear 12 are guided by the inclined surface portion 19 and are laterally incorporated while pushing the holder body 16 upward and upward, and are firmly fixed in the planetary gear holding holes of the holder body 16. Therefore, the stability after the planetary gear 12 is incorporated into the holder body 16 is superior to that of the first embodiment. It goes without saying that the elasticity of the material of the holder body 16 is more effective here as well.

[0026]

As described above, according to the present invention, a large reduction ratio can be obtained with sufficiently small and few parts, high transmission efficiency, small backlash, low noise, excellent dustproofness, and low cost. A compact speed reducer is provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a plan view showing Embodiment 1 of the present invention.

FIG. 3 is a sectional view showing a conventional structure.

FIG. 4 is a sectional view showing a planetary gear unit portion according to another embodiment 2 of the present invention.

FIG. 5 is a plan view showing a planetary gear unit portion according to another embodiment 2 of the present invention.

FIG. 6 is a sectional view showing a planetary gear unit portion according to another embodiment 3 of the present invention.

FIG. 7 is a plan view showing a planetary gear unit portion according to another embodiment 3 of the present invention.

[Explanation of Codes] 1 ... Small motor 2 ... Motor boss 3 ... Motor shaft 4 ... Sun gear 5 ... Sun gear tooth portion 6 ... Lower case member 7 ... Holder body Support part 8 ... Rotation stop tooth profile 9 ... Fixing screw 10 ... Fixed internal gear 11 ... Tooth profile of fixed internal gear 12 ... Planetary gear 13 ... First planetary gear Tooth profile part 14 ... Second tooth profile part of planetary gear 15 ... Shaft 16 ... Holder body 17 ... Planetary gear guide groove 18 ... Strut 19 ... Slope 20 ... Movable Internal gear 21 ... Tooth profile part of movable internal gear 22 ... Output shaft part 23 ... Holder body receiving part 24 ... Outer peripheral part 25 ... Upper case member 26 ... Hooking claw 31 ... Small motor 32 ... Motor shaft 33 ... Motor shaft gear 34 ... Lower case 35 ... -Support shaft 36 ... Planetary gear 37 ... Internal gear 38 ... Intermediate pedestal 39 ... Output shaft gear section 40 ... Output shaft

[Procedure amendment]

[Submission date] November 21, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

[0026]

According to the constitution of claim 1 of the present invention,
The planetary gear has a planetary gear shaft at both ends, and the planetary gear shaft
Through the guide groove of the holder body of the elastic member.
Since it is loosely fitted, the planetary gear can be elastically press-fitted.
Therefore, there is an effect that the assembly of the planetary gear is easy.
According to the configuration of claim 2 of the present invention, the guide
The groove is cut from the outer peripheral part to the center of the planetary gear shaft.
The groove diameter of the outer peripheral part is narrower than that of the planetary gear shaft.
Therefore, it is easy to hold after it is elastically pressed in.
In addition, it has an effect that it is easy to assemble. Also,
According to the third aspect of the present invention, the guide groove has an outer periphery.
A groove is cut from the part to the center of the planetary gear shaft.
Therefore, since the groove depth of the outer peripheral part is deep, elastic press-fitting is easy.
It is easy to hold and easy to assemble
Have an effect .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a plan view showing the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing the structure of the slave come example.

FIG. 4 is a sectional view showing a planetary gear unit section according to a second embodiment of the present invention.

FIG. 5 is a plan view showing a planetary gear unit section according to a second embodiment of the present invention.

FIG. 6 is a sectional view showing a planetary gear unit portion according to a third embodiment of the present invention.

FIG. 7 is a plan view showing a planetary gear unit section according to a third embodiment of the present invention.

[Explanation of Codes] 1 ... Small motor 2 ... Motor boss 3 ... Motor shaft 4 ... Sun gear 5 ... Sun gear tooth portion 6 ... Lower case member 7 ... Holder body Support part 8 ... Rotation stop tooth profile 9 ... Fixing screw 10 ... Fixed internal gear 11 ... Tooth profile of fixed internal gear 12 ... Planetary gear 13 ... First planetary gear Tooth profile part 14 ... Second tooth profile part of planetary gear 15 ... Shaft 16 ... Holder body 17 ... Planetary gear guide groove 18 ... Strut 19 ... Slope 20 ... Movable Internal gear 21 ... Tooth profile part of movable internal gear 22 ... Output shaft part 23 ... Holder body receiving part 24 ... Outer peripheral part 25 ... Upper case member 26 ... Hooking claw 31 ... Small motor 32 ... Motor shaft 33 ... Motor shaft gear 34 ... Lower case 35 ... -Support shaft 36 ... Planetary gear 37 ... Internal gear 38 ... Intermediate pedestal 39 ... Output shaft gear section 40 ... Output shaft

Claims (3)

[Claims] 1. A sun gear that is directly connected to a motor shaft of a motor that rotates at high speed and that rotates coaxially with the motor shaft, a first gear that meshes with the sun gear, and a first gear that is directly connected to the first gear and has the same number of teeth. And a second gear having different diameters, which revolves around the sun gear while revolving around the sun gear, and meshes with the first gear of the planetary gear and is fixed concentrically with the motor shaft of the motor. A fixed internal gear, a movable internal gear that meshes with the second gear of the planetary gear, and rotates concentrically with the motor shaft in association with the revolution of the planetary gear, and is directly connected to the internal gear. A small reduction gear having an output shaft that is coaxial with the shaft, wherein the planetary gear has planetary gear shafts at both ends, and the planetary gear shaft is provided in a holder body of an elastic member and a guide groove of the holder body. Small deceleration characterized by being loosely fitted through Machine. 2. The small reduction gear according to claim 1, wherein the guide groove is cut from an outer peripheral portion toward a center of the planetary gear shaft, and a groove diameter of the outer peripheral portion is narrower than that of the planetary gear shaft. Machine. 3. The miniature speed reducer according to claim 1, wherein the guide groove is cut from the outer peripheral portion toward the center of the planetary gear shaft, and the groove depth of the outer peripheral portion is deep.