JP2891120B2 - Small reducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reduction mechanism of 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 compact speed reducer using this type of planetary gear mechanism.

In FIG. 3, a motor shaft gear 33 is driven into a motor shaft 32 at the center of a small motor 31. The lower case part 34 is attached to the small motor 31 by screw connection with the motor shaft 32 as the center axis. The lower case portion 34 has two to four support shafts 35, and the planetary gears 36 are fitted into the support shafts 35, respectively. A plurality of planetary gears 36 mesh with an internal gear 33 on the inner periphery and an internal gear 37 meshes on the outer periphery. At the center of the internal gear 37 is an output shaft gear 39. The intermediate support 38 is connected to the lower case section 39, serves as a bearing for the output shaft gear section 39, and has a support shaft 35. The output shaft gear 39 meshes with the planetary gear 36, and the planetary gear 36 meshes with the internal gear 37. In this way, the gear at the center becomes the driving force, and the rotation of the inner gear 37 via the planetary gear 36 is 1
When a set is used, when the reduction gear ratio is large, the mechanism is such that the sets are stacked in multiple stages. In the last stage of the set, the output shaft 40 is located at the center of rotation of the internal gear 37.

[0004]

In such a small speed reducer using a planetary gear mechanism having the conventional configuration, the motor shaft gear 33 meshes with the internal gear 37 via the planetary gear 36 to reduce the speed. One set of reduction ratios from the gear 33 to the internal gear 37 is small, and in order to obtain a large reduction ratio, several sets of wheel trains are required. Thus, in order to reduce the speed by combining a number of gears, a number of gear parts are used.
For this reason, there was a problem that the cost increased, the noise was large, and the backlash was large.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. It aims at reducing the number of parts and cost, and is compact and lightweight, has a large reduction ratio, and has a small backlash. It is an object of the present invention to provide an inexpensive small speed reducer having high transmission efficiency.

[0006]

SUMMARY OF THE INVENTION A compact speed reducer according to the present invention comprises:
A sun gear fixed to the input shaft and a planet that meshes with the sun gear
Gears and planetary gears rotate freely and revolve around sun gears
Freely supporting holder and fixed to mesh with planetary gears
The internal gear and the planetary gear mesh with the output shaft at the base end.
With a planetary gear mechanism consisting of a movable internal gear formed with
Planetary gears protrude at both ends in the axial direction
Gear shaft, and the holder body supports the gear shaft
A pair of bearing members to be held and a pair of bearing portions are connected to each other.
It is formed integrally with the supporting pillar member, and each bearing part has
Planetary gear holding hole that supports the bearing part so that the gear shaft can rotate freely
Extending radially from the bearing surface to the planet gear holding hole.
Planetary gear guide for guiding the gear shaft from being mounted in the radial direction
A groove is formed through the shaft in the axial direction.
Is the width that regulates the position of the gear shaft mounted on the planet gear holding hole.
A narrow portion is formed, and mounting from the radial direction of the gear shaft
Allowable when the guide groove forming part of the bearing part expands in the circumferential direction
It is characterized by being performed .

Another small speed reducer of the present invention is fixed to an input shaft.
Sun gear, planet gears that mesh with the sun gear, and planets
Supports gears to rotate freely and revolve around sun gear
A fixed internal gear that meshes with the planetary gear,
An output shaft can be formed at the base end while meshing with the planetary gear.
Compact speed reducer with planetary gear mechanism consisting of moving internal gear
, The planetary gear has a gear shaft protruding at both ends in the axial direction.
The holder body has a pair of gear shafts that support the gear shaft with both ends.
A bearing member and a column connecting the pair of bearings to each other
The gear shaft is formed integrally with each material
From the planetary gear holding hole to freely support and the peripheral surface of the bearing
Extends to the planet gear holding hole in the radial direction, and
And a planetary gear guide groove for guiding the mounting of the
The gear holding hole passes through the bearing part in the axial direction, and
The car guide groove is a shallow groove whose inside in the axial direction is open, and the gear shaft
When mounting from the radial direction, the guide groove forming part of each bearing
Characterized by being curved outward in the direction
You .

[0008]

[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 small motor 1 has a motor boss 2 and a motor shaft 3 on a central axis thereof.
There is a sun gear 4 driven into the motor shaft 3. Motor shaft 3
The parts that take the same center axis as the center axis of the sun gear 4,
Lower case member 6, fixed internal gear 10, holder body 16,
There is 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
To the motor 1. The fixed internal gear 10 is fixed to the lower case member 6 by the rotation stop tooth profile 8. The anti-rotation tooth portion 8 has a tooth shape. If the lower case member 6 has a male tooth shape, the fixed internal gear 10 has a female tooth shape and is fitted and fixed to each other.

[0010] The planetary gear 12 is a point-symmetrical
Four are arranged and meshed, and furthermore, the fixed internal gear 10 and the movable internal gear 20 are also meshed. The planetary gear 12 is held by the holder body 16 such that the center axis is always kept parallel to the center 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 are supported at both ends. The holder body 16 is composed of a planetary gear guide groove 17 as a bearing part of the planetary gear 12 and a column 18 for increasing torsional rigidity.

Hereinafter, a unit in which the planetary gears 12 are incorporated into the holder body 16 and fixed is referred to as a planetary gear unit. The planetary gear unit is supported at both ends by using the holder body support base 7 at the lower end and the holder body press receiving portion 23 as a bearing at the upper end, 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 incorporated from the lateral direction. Therefore, here, since it is not necessary to separate the holder body 16 into upper and lower parts and hold down the planetary gear 12,
The number of parts of the holding member is reduced and the efficiency of assembly is increased.

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

The movable internal gear 20 is formed of an outer peripheral portion 24 on the outside of the internal tooth profile and an output shaft portion 22 at the center, and the outer peripheral portion 24 at the lower end has a lower case member 6 and an output shaft portion at the upper end. Reference numeral 22 denotes an upper case member 25 which constitutes a bearing portion supported at both ends, 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, and covers the entire small speed reducer. ing.

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

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

Therefore, when the sun gear 4 rotates, the fixed internal gear 10 does not work, so that the planetary gear 12 starts rotating and revolving. 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. For this reason, the rotation of the planetary gear 12 and the revolution thereof cause the fixed internal gear 1 to rotate.
The tooth profile of the movable internal gear 20 is shifted from zero. with this,
The movable internal gear 20 rotates at a reduced speed. This is represented by the following equation.

[0017] In the above formulas, the usage of the numbers 1 to 4 is an integer that is the same for both the numerator and the denominator.

In this manner, 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 section 22.

FIG. 2 is a plan view of the present embodiment. As shown in FIG. 2, the number of the planetary gears is two, but may be one in theory. However, from the balance of force, two to four gears are most preferable, and three gears are most preferable. However, according to the above formula, the number of planetary gears is also limited by the reduction ratio.

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

This means that the periphery of the output shaft 22 must have strength to withstand a large torque, but this mechanism has a structure that can withstand a large torque in principle. First,
When the output shaft torque is replaced by the tooth profile 21 of the movable internal gear, the radius received from the center is large, so that the force received by the tooth profile 21 is small. There are a plurality of planetary gears 12. Furthermore, the meshing ratio between the tooth profile 21 of the movable internal gear and the second tooth profile 14 of the planetary gear is large. As described above, the load applied to each tooth of the tooth profile 21 of the movable internal gear, the second tooth profile 14 of the planetary gear, the first tooth profile 13 of the planetary gear, and the tooth profile 11 of the fixed internal gear is small. As a result, the torque of the output shaft portion 22 is increased.

Further, since a high reduction ratio can be achieved by a combination of a small number of gears, the backlash is small, and the number of parts is small.

Further, the speed reduction mechanism is provided on the lower case member 6.
And the upper case member 25, so that noise is small,
It is a small reduction gear that is difficult for dust to enter.

FIG. 4 is a sectional view of a planetary gear unit according to another embodiment 2 of the present invention. FIG. 5 is a plan view of a planetary gear unit according to the second embodiment. Here, a planetary gear guide groove 17 formed from the outer periphery of the holder body 16
The planetary gear guide groove 17 is formed so as to be longer than the radius of the axle portion from the outer periphery of the holder body 16 to the shaft 15 which is the axle portion, and is formed outside the center of the axle portion. Is formed smaller than the diameter of the axle portion. Therefore, the upper and lower shafts 15 of the planetary gear 12 are assembled from the lateral direction while spreading this part in a plane direction (the direction of the display surface in FIG.
Is firmly fixed to the planetary gear holding hole. Therefore,
As compared with the first embodiment, the planetary gears 12
Excellent in stability after being incorporated into 6. In such a structure, since the planetary gear 12 is press-fitted into the holder body 16, the material of the holder body 16 has elasticity like plastic.

FIG. 6 is a sectional view of a planetary gear unit according to another embodiment 3 of the present invention. FIG. 7 is a plan view of a planetary gear unit according to the third embodiment. Here, a planetary gear guide groove 17 formed from the outer periphery of the holder body 16
The groove is preferably formed in the thickness direction of the holder body 16, the groove depth is ３ 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 gears 12 are guided by the slopes 19 to push the holder body 16 up and down while being assembled from the lateral direction and firmly fixed to the planetary gear holding holes of the holder body 16. That is, the planetary gear guide groove 17 is formed to be longer than the radius of the axle portion from the outer periphery of the holder body 16 toward the shaft 15 as the axle portion, and the depth of the outer portion is greater than the end position of the axle portion. It is formed shallow. Therefore, the stability after the planetary gears 12 are assembled in the holder body 16 is superior to that of the first embodiment. Also here, the material of the holder body 16 has elasticity.

[0026]

As described above, according to the present invention, the following effects can be obtained. According to the first aspect, the planetary gears are supported by the holder body at both ends by arranging and fixing the axle portions formed at both ends of the planetary gear at the innermost portion of the guide groove of the holder body. Since the assembling can be performed only by introducing the axle, the assembling work of the planetary gears is facilitated, and the number of parts is reduced, so that the manufacturing cost can be reduced. Further, by fixing the axle portion of the planetary gear, the inclination of the planetary gear due to the torsional moment or the like can be suppressed, and the meshing with the fixed / movable internal gear and the like can be stabilized. According to the second or third aspect, after the axle is pressed into the guide groove, the axle is fixedly held at a predetermined position in the guide groove by the shape of the guide groove. The stability of the mounted state of the planetary gears can be increased without impairing the performance.

[Brief description of the 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 according to a second embodiment of the present invention.

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Small motor 2 ... Motor boss 3 ... Motor shaft 4 ... Sun gear 5 ... Tooth profile part of sun gear 6 ... Lower case member 7 ... Holder body support part 8 .... · Anti-rotation tooth portion 9 ··· fixed screw 10 ··· fixed internal gear 11 ··· fixed tooth gear portion 12 ··· planetary gear 13 ··· first tooth shape portion of planetary gear 14 · ..Second tooth profile portion of planetary gear 15: shaft 16: holder body 17: planetary gear guide groove 18: support column 19: slope portion 20: movable internal gear 21 ..Movable internal gear tooth profile 22 ... Output shaft 23 ... Holder receiving part 24 ... Outer periphery 25 ... Upper case member 26 ... Hook 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 support 39 ... Output shaft gear part 40 ... Output shaft

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-222640 (JP, A) JP-A-56-70150 (JP, A) JP-A-48-19958 (JP, A) JP-A-62 1670 (JP, A) JP-A-60-208657 (JP, A) JP-A 50-36968 (JP, U) JP-A 51-132484 (JP, U) JP-A 50-10807 (JP, Y1) 37-13925 (JP, Y1) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16H 1/28 F16H 1/36

Claims (2)

(57) [Claims] A sun gear fixed to an input shaft;
Planetary gear meshing with the gears, and the planetary gears can rotate freely
And a holder body rotatably supported around the sun gear
A fixed internal gear that meshes with the planetary gear;
Movable inside that meshes with gears and has an output shaft at the base end
Small reduction gears equipped with a planetary gear mechanism
The planetary gear has a gear shaft protruding at both ends in the axial direction, and the holder body has a pair of supports that support the gear shaft at both ends.
Bearing member and the pair of bearing portions are interconnected.
The bearing unit is formed integrally with a support member, and the bearing unit is configured to rotate the gear shaft.
A planetary gear holding hole that freely supports, and a peripheral surface of the bearing portion
From the gear shaft to the planet gear holding hole,
The planetary gear guide groove that guides the mounting of the
Direction, and each planetary gear guide groove is attached to the planetary gear holding hole.
A narrow portion for regulating the position of the gear shaft is formed, and
The mounting of the gear shaft from the radial direction is based on the plan of each bearing portion.
A small reduction gear, wherein the inner groove forming portion is allowed to expand in a circumferential direction . 2. A sun gear fixed to an input shaft;
Planetary gear meshing with the gears, and the planetary gears can rotate freely
And a holder body rotatably supported around the sun gear
A fixed internal gear that meshes with the planetary gear;
Movable inside that meshes with gears and has an output shaft at the base end
Small reduction gears equipped with a planetary gear mechanism
The planetary gear has a gear shaft protruding at both ends in the axial direction, and the holder body has a pair of supports that support the gear shaft at both ends.
Bearing member and the pair of bearing portions are interconnected.
The gear shaft is formed integrally with a support member, and each of the bearing portions rotatably supports the gear shaft.
The radial contact from the planet gear holding hole and the peripheral surface of the bearing
It extends to the planetary gear holding hole and extends from the radial direction of the gear shaft.
A planetary gear guide groove for guiding the mounting is formed, and each of the planetary gear holding holes penetrates the bearing portion in the axial direction.
And each of the planetary gear guide grooves is opened on the inner side in the axial direction.
It is a shallow groove, and the mounting from the radial direction of the gear shaft is
The guide groove forming part of each bearing part is curved outward in the axial direction.
A compact reducer characterized by being allowed in .