JP2014055653A - Planetary gear speed reduction mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planetary gear speed reduction mechanism capable of achieving high speed reduction with a simpler configuration without spoiling intensity.SOLUTION: A planetary gear speed reduction mechanism includes: a sun gear 11 which becomes an input axis; a fixing ring gear 12; a stepped planetary gear 20 having a first gear part 21 and a second gear part 22 whose diameter is smaller than that of the first gear part 21; carriers 23 and 24 which rotatably support the stepped planetary gear 20 and which support the stepped planetary gear 20 so that it can freely revolve around the sun gear 11; and a movable ring gear 14 which becomes an output axis. The first gear part 21 engages with the sun gear 11 and the fixing ring gear 12, and the second gear part 22 engages with the movable ring gear 14. The tooth number difference between the first gear part 21 and the second gear part 22 is set to be "4".

Description

  The present invention relates to a planetary gear reduction mechanism.

  Conventionally, various types of so-called 3K type planetary gear reduction mechanisms have been proposed. For example, the planetary gear speed reduction mechanism described in Patent Document 1 includes a stepped planetary gear 90 having a first gear portion 91 and a second gear portion 92 having a smaller diameter than the first gear portion 91 as shown in FIG. I have. The first gear portion 91 and the second gear portion 92 have the same number of teeth, that is, the difference in the number of teeth is set to zero. Therefore, when the sun gear meshed with the first gear portion 91 is used as the input shaft and the movable ring gear meshed with the second gear portion 92 is used as the output shaft, the rotational speed of the sun gear can be significantly reduced and output from the movable ring gear. Be expected.

JP 2003-207028 A Japanese Patent Laid-Open No. 2004-19900

  Incidentally, in the stepped planetary gear 90 of Patent Document 1, the number of teeth of the first gear portion 91 and the second gear portion 92 is set to be equal, so that the tooth size of the second gear portion 92 on the small diameter side is set. The so-called module is relatively small, and the strength of the teeth of the second gear portion 92 is low. On the other hand, for example, when the rotational speed on the input side is sufficiently decelerated and output (hereinafter also referred to as “higher speed reduction”), the strength of the teeth of the second gear portion 92 corresponding to the increase in the output torque associated therewith. It is essential to increase the value.

  In Patent Document 1, in order to increase the strength of the entire stepped planetary gear 90 including the teeth of the second gear portion 92, the stepped planetary gear 90 is configured by stacking metal thin plate gears in phase. Has also been proposed. However, such a stepped planetary gear 90 has a complicated structure and requires high-precision assembly for arranging the first gear portion 91 and the second gear portion 92 in the same phase.

Further, since the difference in the number of teeth between the first gear portion 91 and the second gear portion 92 is zero, if the speed is reduced too much, slippage between teeth increases and efficiency decreases.
In the planetary gear speed reduction mechanism described in Patent Document 2, a stepped planetary gear having a first gear portion and a second gear portion in which both the diameter and the number of teeth of a pitch circle are set to be equal has been proposed. The difference in the number of teeth between the fixed ring gear meshing with the first gear portion and the movable ring gear meshing with the second gear portion is set to “1”.

  In this case, since the modules of the first gear unit and the second gear unit are set to be equal, their strengths are also equal. In addition, when the difference in the number of teeth between the fixed ring gear and the movable ring gear is set to “1”, the sun gear meshing with the first gear portion is used as the input shaft, and the movable ring gear meshing with the second gear portion is used as the output shaft. It is expected that the rotational speed of the sun gear can be significantly reduced and output from the movable ring gear. Furthermore, since the number of stepped planetary gears is set to “4”, the required strength is ensured even if the output torque increases as the speed is reduced.

  However, the number of teeth difference between the fixed ring gear and the movable ring gear is usually set to an integral multiple of the number of planetary gears. In Patent Document 2, in order to realize the difference in the number of teeth of the fixed ring gear and the movable ring gear by “1”, the first gear portions and the four stepped planetary gears are respectively engaged with the fixed ring gear and the movable ring gear. A phase difference is set between the second gear portions. Specifically, the phase difference between the first gear portion and the second gear portion of the four stepped planetary gears is “0”, “1/4”, “2/4”, “3/4”. Is set to

  Therefore, high precision is required for the manufacture of these four stepped planetary gears, and high precision assembly for arranging the four stepped planetary gears at predetermined positions is required. As in Patent Document 1, if the difference in the number of teeth between the first gear portion and the second gear portion is zero and the gear is excessively decelerated, slippage between teeth increases and efficiency decreases.

  An object of the present invention is to provide a planetary gear speed reduction mechanism that can realize high speed reduction with a simpler structure without impairing strength.

  In order to solve the above problems, the invention according to claim 1 is engaged with a sun gear serving as an input shaft, a fixed ring gear disposed coaxially with the sun gear, and the sun gear and the fixed ring gear. A stepped planetary gear having a first gear part and a second gear part having a smaller diameter than the first gear part; and the stepped planetary gear is rotatably supported around the sun gear. And a movable ring gear which is arranged coaxially with the sun gear and meshes with the second gear portion to serve as an output shaft, and has teeth of the first gear portion and the second gear portion. The gist is that the number difference is set to “4”.

  In this type of planetary gear reduction mechanism (so-called 3K type planetary gear reduction mechanism), when the sun gear is used as an input shaft and the movable ring gear is used as an output shaft, teeth of the first gear portion and the second gear portion are used. As the number difference is smaller, the rotational speed of the sun gear can be remarkably reduced and output from the movable ring gear. According to the same configuration, the difference in the number of teeth of the first gear portion and the second gear portion is set to “4”, so that the rotational speed of the sun gear is sufficiently reduced and output from the movable ring gear. Can do. Further, since the difference in the number of teeth of the first gear portion and the second gear portion is “4”, it is possible to suppress the tooth module of the second gear portion on the small diameter side from being reduced, It can suppress that the intensity | strength of a 2nd gear part becomes low. Further, the stepped planetary gear has a two-stage structure of the first gear portion and the second gear portion in which the difference in the number of teeth is set to “4”. There is no need to stack thin plate gears made of the same phase or set a complicated phase difference between the first gear portion and the second gear portion of each of the plurality of stepped planetary gears.

  According to a second aspect of the present invention, in the planetary gear speed reduction mechanism according to the first aspect, the diameter of the root circle of the first gear portion is set to be greater than or equal to the diameter of the tip circle of the second gear portion. It is a summary.

  According to this configuration, the teeth of the first gear portion and the teeth of the second gear portion are not arranged so as to overlap in the axial direction of the stepped planetary gear. Therefore, the structure of the stepped planetary gear can be further simplified, and the number of manufacturing steps can be reduced.

The gist of the invention described in claim 3 is that, in the planetary gear reduction mechanism according to claim 1 or 2, the number of the stepped planetary gears is “2” or “4”.
According to this configuration, for example, when the number of stepped planetary gears is “2”, the number of parts can be reduced. On the other hand, when the number of stepped planetary gears is “4”, the required strength can be ensured by the cooperation of the four stepped planetary gears even when the output torque is large.

  According to a fourth aspect of the present invention, in the planetary gear speed reduction mechanism according to the third aspect, the number of teeth of the first gear portion and the number of teeth of the second gear portion are both set to an integral multiple of “4”. And at least of the four positions arranged at equiangular intervals in the circumferential direction around the axis of the stepped planetary gear, the phases of the teeth of the first gear portion and the teeth of the second gear portion coincide with each other. The gist is that an engaged portion for phase alignment at the time of assembly is provided at one place.

  According to this configuration, when assembling the two or four stepped planetary gears supported by the carrier to the fixed ring gear or the movable ring gear, for example, the engaging portion provided in the phase matching jig Is engaged with the engaged portions of all the stepped planetary gears, so that the carrier members can be assembled with the phases of these stepped planetary gears aligned. For this reason, the assembling property of the carrier member can be improved. In particular, when the engaged portions are disposed at a plurality of locations on each stepped planetary gear, the position adjustment for engaging the engaging portions provided on the phase matching jig with any of the engaged portions. The amount of rotation of the stepped planetary gear required for the above can be reduced.

  According to the present invention, it is possible to provide a planetary gear speed reduction mechanism that can realize a high speed reduction with a simpler structure without impairing strength.

The disassembled perspective view which shows one Embodiment of this invention. The perspective view which shows a fixed ring gear. The list figure which shows the number of teeth of a sun gear, a fixed ring gear, a 1st gear part, a 2nd gear part, and a movable ring gear. The top view which shows the same embodiment. (A)-(c) is explanatory drawing which shows the assembly | attachment aspect of the embodiment. The perspective view which shows a prior art form.

An embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, a so-called 3K type planetary gear reduction mechanism 10 includes a sun gear 11 serving as an input shaft, a fixed ring gear 12 arranged coaxially with the sun gear 11, a carrier member 13, and a sun gear 11. And a movable ring gear 14 which is arranged coaxially and serves as an output shaft.

  The sun gear 11 is formed in a substantially cylindrical shape having a center line extending along the axial direction, and an external gear 11a is formed at the tip of the sun gear 11. The sun gear 11 is drivingly connected to a driving member (not shown) such as a motor.

  The fixed ring gear 12 is formed in a substantially cylindrical shape having a center line extending along the axial direction, and an internal gear 12a is formed on an inner peripheral portion on one side in the axial direction (side closer to the sun gear 11). Yes. In addition, as shown in FIG. 2, a bearing portion 12 c that is expanded via a step 12 b is formed on the inner peripheral portion on the other side in the axial direction of the fixed ring gear 12 (the side far from the sun gear 11). . Note that, in the axial direction, the position of the internal gear 12 a substantially coincides with the position of the external gear 11 a of the sun gear 11.

  As shown in FIG. 1, the carrier member 13 rotates two stepped planetary gears 20 arranged at mutually opposite radial positions around the axis of the sun gear 11, and these stepped planetary gears 20. A pair of carriers 23 and 24 that support the stepped planetary gear 20 in a freely revolving manner around the sun gear 11 are provided. Each stepped planetary gear 20 includes a first gear portion 21 and a second gear having a smaller diameter than the first gear portion 21 on one side and the other side in the axial direction (the side close to the sun gear 11 and the opposite side). Part 22. In the axial direction, the position of the first gear portion 21 substantially coincides with the position of the external gear 11a of the sun gear 11 (and the internal gear 12a of the fixed ring gear 12), and the first gear portion 21 includes the external gear 11a and It meshes with the internal gear 12a. In the axial direction, the position of the second gear portion 22 is included in the position of the bearing portion 12 c of the fixed ring gear 12.

  Both carriers 23 and 24 are overlapped in the axial direction of the sun gear 11 and fastened by a fastener 25 made of, for example, a bolt-nut, and each stepped by the substantially butterfly-shaped support wall portions 23a and 24a. The planetary gear 20 is sandwiched along the axial direction. Each stepped planetary gear 20 is rotatably supported by the carriers 23 and 24 by the support shaft 26 passing through the support wall portions 23a and 24a in the axial direction thereof.

  The movable ring gear 14 is formed in a substantially bottomed cylindrical shape whose center line extends along the axial direction, and the outer diameter thereof is set to be equal to the inner diameter of the bearing portion 12 c of the fixed ring gear 12. The movable ring gear 14 is rotatably mounted on the bearing portion 12 c of the fixed ring gear 12. An internal gear 14 a is formed on the inner peripheral portion of the movable ring gear 14. In the axial direction, the position of the internal gear 14 a substantially coincides with the position of the second gear portion 22 of the stepped planetary gear 20, and the internal gear 14 a meshes with the second gear portion 22.

  The movable ring gear 14 is provided with a substantially columnar output portion 14b protruding along the axial direction. The movable ring gear 14 is connected to an appropriate driven member (not shown) at the output portion 14b.

  When the sun gear 11 is driven, the rotation is transmitted to the movable ring gear 14 through the carrier member 13. As a result, the rotational speed of the sun gear 11 is sufficiently reduced and output from the movable ring gear 14.

Here, an example of the number of teeth of the sun gear 11, the fixed ring gear 12, the first gear portion 21, the second gear portion 22, and the movable ring gear 14 will be described.
As shown in FIG. 3, in this embodiment, the number of teeth of the sun gear 11 is “14”, the number of teeth of the fixed ring gear 12 (internal gear 12a) is “72”, and the number of teeth of the first gear portion 21 is “28”, the number of teeth of the second gear portion 22 is set to “24”, and the number of teeth of the movable ring gear 14 is set to “68”. That is, the number of teeth of the sun gear 11, the fixed ring gear 12, the first gear portion 21, the second gear portion 22, and the movable ring gear 14 are all set to an integer multiple of “2.” More precisely, the number of teeth other than the sun gear 11 is set to an integral multiple of “4”. The difference in the number of teeth between the first gear portion 21 and the second gear portion 22 is set to “4 (= 28−24)”.

  The teeth of the sun gear 11, the fixed ring gear 12, the first gear portion 21, the second gear portion 22, and the movable ring gear 14 are equivalent to standard gears and are the same module. And the 1st gear part 21 is forward-shifted, and the 2nd gear part 22 is negatively shifted. Thereby, even if the difference in the number of teeth of the first gear portion 21 and the second gear portion 22 corresponding to the standard gear and the same module is “4”, the diameter of the root circle of the first gear portion 21 is The diameter is set to be equal to or larger than the diameter of the tip circle of the second gear portion 22. Accordingly, the teeth of the first gear portion 21 and the teeth of the second gear portion 22 are not arranged in the axial direction of the stepped planetary gear 20.

Next, the operation of this embodiment will be described.
In this embodiment, by setting the difference in the number of teeth of the first gear portion 21 and the second gear portion 22 to “4”, the rotational speed of the sun gear 11 can be sufficiently reduced and output from the movable ring gear 14. it can. That is, a high speed reduction with a gear ratio of 66.4 is realized by setting the number of teeth shown in FIG.

  For example, if the difference in the number of teeth is “5”, even if the module of the tooth of the first gear portion and the tooth of the second gear portion of the stepped planetary gear is the same as that of the standard gear, they are the stepped planetary gears. Although it does not overlap in the axial direction of the gear, five stepped planetary gears are required. On the other hand, in order to set the number of stepped planetary gears to “3”, the difference in the number of teeth becomes “6”. When the difference in the number of teeth is “6”, for example, the number of teeth of the sun gear is “18”, the number of teeth of the fixed ring gear is “72”, the number of teeth of the first gear portion is “27”, and the second gear portion. If the number of teeth is set to “21” and the number of teeth of the movable ring gear is set to “66”, the gear ratio is 33. Further, when the difference in the number of teeth is “3” or less, unless the tooth module of the second gear portion is made smaller than the teeth of the first gear portion of the stepped planetary gear corresponding to the standard gear, The teeth and the teeth of the second gear portion overlap in the axial direction of the stepped planetary gear. Further, although the difference in the number of teeth is small, high speed reduction is possible, but the slip between the teeth increases and the efficiency is lowered.

Next, the assembly method of this embodiment will be described.
As described above, the number of teeth of the first gear portion 21 and the number of teeth of the second gear portion 22 are both integer multiples of “4”, and the difference in the number of teeth of the first gear portion 21 and the second gear portion 22 is as follows. By being “4”, as shown in FIG. 4, the teeth of the first gear portion 21 and the teeth of the second gear portion 22 are equiangular in the circumferential direction around the axis of the stepped planetary gear 20 (90 °) The phase is in agreement at the four locations arranged at intervals.

  Therefore, in the two-stage planetary gear 20, the teeth of the first gear portion 21 and the teeth of the second gear portion 22 that are in phase with each other are arranged farthest in the radial direction around the axis of the sun gear 11. At this time, the sun gear 11 can mesh with the stepped planetary gear 20 (the first gear portion 21) by arranging the tooth groove of the external gear 11a along the radial direction. Similarly, the fixed ring gear 12 can mesh with both stepped planetary gears 20 (first gear portion 21) by arranging the tooth grooves of the internal gear 12a along the radial direction. By arranging the tooth groove of the internal gear 14a along the radial direction, it is possible to mesh with the two-stage planetary gear 20 (second gear portion 22). In other words, the carrier member 13 positions the planetary gear 20 with the two steps by using the angular position of the position where the teeth of the first gear portion 21 and the teeth of the second gear portion 22 match. Assembly to the movable ring gear 14 or the like is further smoothed.

  In the stepped planetary gear 20 of the present embodiment, 4 from the first gear portion 21 side according to the angular positions of the four positions where the teeth of the first gear portion 21 and the teeth of the second gear portion 22 match. A substantially circular phasing hole 27 is formed as one engaged portion. These phasing holes 27 extend in parallel to the axial direction of the stepped planetary gear 20. Further, the phase determining hole 27 is exposed from the carrier 23 (supporting wall portion 23a) when the phase determining hole 27 is disposed farthest in the radial direction around the axis of the carrier member 13 (sun gear 11).

  Here, when the carrier member 13 is assembled to the movable ring gear 14, a substantially cylindrical phasing jig 30 shown in FIG. 5A is used. The phasing jig 30 has an outer diameter and an inner diameter set in accordance with a phasing hole 27 that is arranged farthest in the radial direction around the axis of the carrier member 13 (sun gear 11). A substantially cylindrical phasing pin 31 is protruded as two engaging portions that can be fitted into the phasing hole 27 of the stepped planetary gear 20.

  When the carrier member 13 is assembled, the carrier member 13 is arranged so that one phase determining hole 27 of the stepped planetary gear 20 is farthest away in the radial direction around the axis of the carrier member 13. And the axis direction of the phasing jig 30 are made to coincide with each other. The carrier member 13 and the phasing jig 30 are in a state where the phasing holes 27 of the stepped planetary gear 20 and the phasing pins 31 of the phasing jig 30 are opposed to each other in parallel to the axial direction. They are moved relative to each other in the axial direction so as to approach.

  As a result, the both phase determining pins 31 of the phase determining jig 30 are fitted into the corresponding phase determining holes 27 of the two-stage planetary gear 20, and as shown in FIG. The rotation of both stepped planetary gears 20 with respect to is locked together. At this time, in the two-stage planetary gear 20, one position where the teeth of the first gear portion 21 and the teeth of the second gear portion 22 coincide is most distant in the radial direction centered on the axis of the carrier member 13. Needless to say, it is held in a state. That is, the two-stage planetary gear 20 is held in a state in which the phases are matched by the phasing jig 30.

  Subsequently, the axial direction of the carrier member 13 held by the phasing jig 30 is made to coincide with the axial direction of the movable ring gear 14, and the tooth grooves of the internal gear 14a are arranged along the radial direction. In this state, when the carrier member 13 and the movable ring gear 14 are relatively moved in the axial direction so as to approach each other, the corresponding teeth of the two-stage planetary gear 20 (second gear portion 22) are moved to the opposite inner gear 14a. The second gear portion 22 and the internal gear 14a (movable ring gear 14) are engaged with each other in the tooth gap.

  After that, when the phasing jig 30 is removed from the carrier member 13 as shown in FIG. 5 (c), the carrier member 13 is in a state in which the two-stage planetary gear 20 is rotatable with respect to both the carriers 23 and 24. Connected to the movable ring gear 14. The sun gear 11 and the fixed ring gear 12 are in phase with the carrier member 13 connected to the movable ring gear 14 by the above-described phase alignment. Therefore, even if the phase determination jig 30 is removed, the carrier member 13 (and It can be smoothly assembled to the movable ring gear 14).

As described above in detail, according to the present embodiment, the following effects can be obtained.
(1) In this embodiment, by setting the difference in the number of teeth of the first gear portion 21 and the second gear portion 22 of the stepped planetary gear 20 to “4”, the rotational speed of the sun gear 11 is sufficiently reduced. Can be output from the movable ring gear 14. Further, since the difference in the number of teeth of the first gear portion 21 and the second gear portion 22 is “4”, it is possible to suppress the tooth module of the second gear portion 22 on the small diameter side from being reduced, It can suppress that the intensity | strength of the 2nd gear part 22 becomes low. Further, the stepped planetary gear 20 has a two-stage structure including a first gear portion 21 and a second gear portion 22 in which the difference in the number of teeth is set to “4”. There is no need to stack thin plate gears made of the same phase or set a complicated phase difference between the first gear portion and the second gear portion of each of the plurality of stepped planetary gears.

  (2) In the present embodiment, the diameter of the root circle of the first gear portion 21 is set to be equal to or larger than the diameter of the tip circle of the second gear portion 22, so that the first gear portion 21 and the second gear are set. The teeth of the portion 22 are not arranged overlapping the axial direction of the stepped planetary gear 20. Therefore, the structure of the stepped planetary gear 20 can be further simplified, and the number of manufacturing steps can be reduced.

  In particular, as the construction method of the stepped planetary gear 20, a construction method (resin injection molding / sintering) in which the phase is determined on one side of the mold can be selected. Therefore, the phases of the first gear portion 21 and the second gear portion 22 can be determined by the mold, and accuracy can be easily ensured.

As described above, the manufacturing cost can be reduced.
In addition, when the phases of the first gear portion 21 and the second gear portion 22 are determined by the mold, even if the phases of the first gear portion 21 and the second gear portion 22 are shifted, the shift is all stepped. Since it is common to the planetary gears 20, there is substantially no influence on the operation and performance of the stepped planetary gears 20 and the like.

(3) In this embodiment, since the number of stepped planetary gears 20 is “2”, the number of parts can be reduced, and the cost can be reduced.
(4) In the present embodiment, equiangular intervals (90 °) in the circumferential direction centering on the axis of the stepped planetary gear 20 in which the teeth of the first gear portion 21 and the teeth of the second gear portion 22 match. The phase determining holes 27 for phase alignment at the time of assembling are provided in accordance with all the angular positions of the four positions arranged in FIG. Accordingly, when the two stepped planetary gears 20 supported by the carriers 23 and 24 are assembled to the movable ring gear 14, the two phase determining pins 31 provided on the phase determining jig 30 are connected to the two stepped planetary gears 20 respectively. The carrier member 13 can be assembled by aligning the phases of the stepped planetary gears 20 by engaging with the phase determining holes 27. For this reason, the assembling property of the carrier member 13 can be improved.

  In particular, since the phase determining holes 27 are provided at four locations of each stepped planetary gear 20, the phase determining pins 31 provided in the phase determining jig 30 are engaged with the arbitrary phase determining holes 27. Therefore, the amount of rotation of the stepped planetary gear 20 required for position adjustment can be reduced. Specifically, for example, when the phase determining hole 27 is provided only at one position of each stepped planetary gear 20, the rotation amount of the stepped planetary gear 20 required for position adjustment is approximately 180 ° at the maximum. On the other hand, the rotation amount of the stepped planetary gear 20 required for position adjustment is suppressed to about 45 ° at the maximum by arranging the phase determining holes 27 at the four positions of each stepped planetary gear 20.

  (5) In this embodiment, the phase determining hole 27 of each stepped planetary gear 20 into which the phase determining pin 31 of the phase determining jig 30 is fitted can be selected from four locations. Matching can be performed smoothly.

  (6) In the present embodiment, the first gear portion 21 of the stepped planetary gear 20 has been forwardly displaced, so that the teeth can be prevented from being cut down, and the second gear portion 22 has been negatively displaced, the teeth of the teeth. Sharpness can be suppressed.

In addition, you may change the said embodiment as follows.
In the above-described embodiment, the first gear portion 21 of the stepped planetary gear 20 is forwardly shifted and the second gear portion 22 is negatively shifted. On the other hand, if the diameter of the root circle of the first gear portion 21 is equal to or larger than the diameter of the tip circle of the second gear portion 22, only the first gear portion 21 may be forwardly shifted. Only the second gear portion 22 may be negatively displaced. Alternatively, both the first gear portion 21 and the second gear portion 22 may be forwardly shifted so that the shift amount of the first gear portion 21 is larger than the shift amount of the second gear portion 22.

  -In the said embodiment, the phase determination hole 27 is equiangular in the circumferential direction centering on the axis line of the stepped planetary gear 20 with which the phase of the tooth | gear of the 1st gear part 21 and the tooth | gear of the 2nd gear part 22 corresponds. What is necessary is just to provide according to the angle position of at least one place of four places arrange | positioned by a space | interval (90 degrees). Even in this case, when the two stepped planetary gears 20 supported by the carriers 23 and 24 are assembled to the movable ring gear 14, the two phasing pins 31 provided on the phasing jig 30 are both attached. By engaging with the phase determining hole 27 of the stepped planetary gear 20, the carrier member 13 can be assembled with the phases of the stepped planetary gears 20 aligned.

  In the case where the phase determining holes 27 are provided at two locations on each stepped planetary gear 20, it is more preferable that the two locations are opposed in the radial direction around the axis of the stepped planetary gear 20. . This is to reduce the amount of rotation of the stepped planetary gear 20 required for position adjustment for engaging the phase determination pin 31 provided in the phase determination jig 30 with the arbitrary phase determination hole 27.

  In the above-described embodiment, the phase determining hole 27 is provided in the stepped planetary gear 20, and the phase determining pin 31 is provided in the phase determining jig 30. On the other hand, the stepped planetary gear 20 may be provided with a phasing pin as an engaged portion, and the phasing jig 30 may be provided with a phasing hole as an engaging portion into which the phasing pin can be fitted. Good.

  In the above embodiment, the fixed ring gear 12 is assembled after the carrier member 13 in a state where the rotation of the two-stage planetary gears 20 with respect to both the carriers 23 and 24 is locked together by the phasing jig 30 is assembled to the movable ring gear 14. And so on. On the other hand, the carrier member 13 in a state where the rotation of the two-stage planetary gears 20 with respect to both the carriers 23 and 24 is locked together by the phasing jig is assembled to the fixed ring gear 12, and then the movable ring gear 14 and the like are assembled. You may do it. However, it is more preferable that the phasing jig for holding the carrier member 13 stops the rotation of the two-stage planetary gear 20 from the second gear portion 22 side in order to avoid interference with the fixed ring gear 12.

  In the embodiment, the number of stepped planetary gears may be “4”. However, in this case, the number of teeth of the sun gear, the fixed ring gear, the first gear portion, the second gear portion, and the movable ring gear must all be set to an integer multiple of “4”. As a result, the rotation of the sun gear can be output from the movable ring gear via the four stepped planetary gears and the like disposed at equiangular (90 °) intervals. In this case, even when the output torque is large, the required strength can be ensured by the cooperation of these four stepped planetary gears.

  When the carrier member is assembled, when the rotation of the four stepped planetary gears relative to the carrier is locked by the phase determination jig, one phase determination hole of the four stepped planetary gears is used. Are arranged so as to be farthest in the radial direction around the axis of the carrier member. Then, the four phasing pins arranged in the phasing jig corresponding to these phasing holes may be inserted into the phasing holes. The arrangement relationship between the stepped planetary gear and the phasing jig, the phasing hole and the phasing pin may be reversed.

  In the above embodiment, if the first gear portion 21 and the second gear portion 22 are equivalent to a standard gear and are in the same module, the teeth of the first gear portion 21 and the teeth of the second gear portion 22 are stepped. It may be arranged so as to overlap the axial direction of the attached planetary gear 20.

-In the said embodiment, the setting of the number of teeth of a sun gear, a fixed ring gear, a 1st gear part, a 2nd gear part, and a movable ring gear is an example.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.

(A) In the planetary gear reduction mechanism according to claim 1 or 2,
The planetary gear speed reduction mechanism, wherein the number of teeth of the sun gear, the fixed ring gear, the first gear portion, the second gear portion, and the movable ring gear is set to an integral multiple of “4”. According to this configuration, “2” or “4” can be selected as the number of the stepped planetary gears. When “2” is selected as the number of the stepped planetary gears, the number of parts can be reduced. When “4” is selected, the four stepped planetary gears cooperate with each other. The strength of the can be ensured.

(B) In the planetary gear reduction mechanism according to claim 1 or 2,
The number of teeth of the sun gear, the fixed ring gear, the first gear portion, the second gear portion, and the movable ring gear is set to an integer multiple of “2” (non-integer multiple of “4”). Planetary gear reduction mechanism characterized by this. According to this configuration, the number of stepped planetary gears is “2”, and the number of parts can be reduced.

  DESCRIPTION OF SYMBOLS 10 ... Planetary gear reduction mechanism, 11 ... Sun gear, 12 ... Fixed ring gear, 14 ... Movable ring gear, 20 ... Stepped planetary gear, 21 ... First gear part, 22 ... Second gear part, 23, 24 ... Carrier, 27 ... phase determining hole (engaged portion), 30 ... phase determining jig, 31 ... phase determining pin (engaging portion).

Claims (4)

A sun gear as an input shaft,
A fixed ring gear arranged coaxially with the sun gear;
A stepped planetary gear having a first gear portion meshing with the sun gear and the fixed ring gear, and a second gear portion having a smaller diameter than the first gear portion;
A carrier that rotatably supports the stepped planetary gear and supports the stepped planetary gear so as to revolve around the sun gear;
A movable ring gear disposed coaxially with the sun gear and meshing with the second gear portion to serve as an output shaft;
A planetary gear reduction mechanism, wherein a difference in the number of teeth of the first gear portion and the second gear portion is set to “4”. The planetary gear reduction mechanism according to claim 1,
The planetary gear speed reduction mechanism, wherein a diameter of a root circle of the first gear portion is set to be equal to or larger than a diameter of a tip circle of the second gear portion. In the planetary gear reduction mechanism according to claim 1 or 2,
The planetary gear speed reduction mechanism, wherein the number of stepped planetary gears is “2” or “4”. The planetary gear reduction mechanism according to claim 3,
The number of teeth of the first gear portion and the number of teeth of the second gear portion are both set to an integer multiple of “4”,
At least one of the four positions arranged at equiangular intervals in the circumferential direction centering on the axis of the stepped planetary gear, the phases of the teeth of the first gear portion and the teeth of the second gear portion match. A planetary gear reduction mechanism characterized in that an engaged portion for phase alignment at the time of assembly is provided.