JP2019044813A - Planetary gear mechanism, and geared motor with this planetary gear mechanism - Google Patents

Abstract

To reduce rotational resistance.SOLUTION: In a rotation center side of at least one of a front end surface of a first sun gear 11 and a rear end surface of a first carrier 31 in a front side of the first sun gear 11, a convex curve part 10a a rotation center side of which protrudes like a convex curve surface is provided. The convex curve part 10a is brought into contact with the other surface opposite to the one surface.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a planetary gear mechanism and a geared motor provided with the planetary gear mechanism.

Conventionally, in this type of invention, as described in, for example, Patent Document 1, a sun gear integrally having a shaft portion on the front side of a central portion, and a plurality of planetary gears meshed with outer teeth of the sun gear; A planetary gear mechanism comprising: a carrier engaged with and rotated on a shaft portion on the front side of the sun gear, and a carrier rotatably supporting the plurality of planet gears, and an internal gear meshing with the plurality of planet gears on the periphery side Are connected in a multistage manner, and there is a geared motor in which a sun gear (drive gear) located on the most input side is fixed to the rotation shaft of the motor.
In this conventional geared motor, a bottomed hole (boss) is provided on the center side of the rear end surface of the carrier, and the shaft portion on the front side of the sun gear is inserted into the bottomed hole. Lubricating grease is applied to sliding parts such as the shaft part.

JP, 2016-15794, A

  However, according to the above-mentioned prior art, the rotational resistance due to the friction between the shaft portion on the front side of the sun gear and the carrier in which the bottomed hole is fitted to this shaft portion is large. The grease clay accumulated in the bottom holes may be high, and the rotational resistance may be significantly increased.

In order to solve such a subject, the present invention comprises the following composition.
A sun gear, a planetary gear meshed with an outer peripheral tooth portion of the sun gear, a carrier that rotates on the front side of the sun gear and rotatably supports the plurality of planetary gears, and the plurality of planetary gears In a planetary gear mechanism provided with an internal gear meshing on the peripheral side thereof, at least one of the front end surface of the sun gear and the rear end surface of the carrier on the front side of the sun gear, What is claimed is: 1. A planetary gear mechanism, comprising: a convex curved portion that protrudes in a substantially convex curved surface shape, wherein the convex curved portion is in contact with the other surface with respect to the one surface.

It is principal part sectional drawing which shows an example of the geared motor provided with the planetary gear mechanism which concerns on this invention. It is the II section enlarged view of FIG. It is the III section enlarged view of FIG. It is the IV section enlarged view of FIG. It is the V section enlarged view of FIG. It is a disassembled perspective view of the same planetary gear mechanism. It is a perspective view showing an example of a career. It is an enlarged view which shows an example of a recessed part. (A) is an electronic device provided with a geared motor according to the present invention, (b) is a robot provided with the same geared motor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings denote portions having the same functions, and redundant description in each drawing will be appropriately omitted. In the following description, the output side (upper side according to FIG. 1) may be expressed as “front” and the input side (lower side according to FIG. 1) as “rear”.

1 and 6 show an example of a geared motor provided with a planetary gear mechanism according to the present invention.
The geared motor A includes a motor 1 and a planetary gear mechanism 2 rotated by the driving force of the motor 1. The planetary gear mechanism 2 reduces the rotational speed of the rotation shaft 10 of the motor 1 to, for example, about 40 to 60 rpm. Do.

  The motor 1 is an electric motor configured to drive and rotate a rotating shaft 10 projecting forward. For example, a DC motor capable of controlling the rotation angle of the rotary shaft 10 can be applied to the motor 1.

  The rotation shaft 10 is formed in a long cylindrical shaft shape, and its front end portion is a hemispherical convex curved portion 10 a. The convex curved portion 10 a is located on the rotation center side of the front end surface of the first sun gear 11 described later, and protrudes forward than the front end surface of the first sun gear 11.

  The planetary gear mechanism 2 includes first to third sun gears 11, 12, and 13, and first to third planet gears 21, 22, and 23 meshed with outer teeth of each of the sun gears 11, 12 or 13. The first to third carriers 31, 32 rotate concentrically on the front side of the sun gears 11, 12, or 13 and rotatably support the first to third planetary gears 21, 22, 23 respectively. , 33 and the internal gear 41 meshing with the first to third planetary gears 21, 22 and 23 on the periphery side, and the first to third sun gears 11, 12 and 13 A multistage planetary gear mechanism is configured to rotate the first to third carriers 31, 32, and 33.

The first sun gear 11 is formed in a spur gear shape having teeth along the entire circumference thereof. The first sun gear 11 is annularly fitted on the front end side of the rotating shaft 10 so as to rotate integrally with the rotating shaft 10.
A plurality of (three according to the illustrated example) first planetary gears 21 are disposed around the first sun gear 11 at intervals in the circumferential direction.

The plurality of first planetary gears 21 are arranged at substantially equal intervals around the first sun gear 11.
Each first planetary gear 21 is formed in a spur gear shape having a tooth portion along the entire circumference, and meshes with the first sun gear 11 and also with the internal gear 41 on the inner peripheral surface of the gear case 40.

  The first carrier 31 has a plurality of shaft portions 31 b rotatably supporting the first planetary gear 21 at intervals in the circumferential direction on the rear surface of the disk-shaped base portion 31 a, and The second sun gear 12 is integrally rotatably fixed at a central portion of the front surface.

  The shaft portion 31 b is formed in a cylindrical shape that protrudes rearward, and according to the illustrated example, is integrally formed with the base portion 31 a. On the rear end face of the shaft portion 31b, a convex-curved protrusion 31c which protrudes rearward and is smaller in outer diameter than the shaft portion 31b is formed (see FIG. 3).

  A clearance s1 is provided between the end of the projection 31c and the opposing surface 50a (in the illustrated example, the front surface of the rear end plate 50) of the end. The gap s1 is held by the abutment of the front end of the rotary shaft 10 and the rear end face of the first carrier 31.

Further, the dimension from the base of the shaft portion 31 b to the end of the projection 31 c is set to be longer than the axial dimension of the first planetary gear 21. Further, the axial dimension of the shaft portion 31 b is set to be shorter than the axial dimension of the first planetary gear 21.
Accordingly, an annular gap s2 is secured around the protrusion 31c between the rear end surface of the shaft 31b and the facing surface 50a (see FIG. 3). The gap s2 functions as a grease (lubricant) storage space.

Further, as shown in FIG. 2, a concave portion 31d is provided on the center side of the rear surface of the base portion 31a, and in this concave portion 31d, an opposing convex curved portion facing and contacting the convex curved portion 10a at the front end of the rotary shaft 10. 31d1 is provided.
The recess 31 d is a space having a cylindrical peripheral wall surface, and the oppositely convexly curved portion 31 d 1 is provided so as to protrude rearward from the bottom of the recess 31 d (see FIGS. 2 and 8).

The oppositely convexly curved portion 31 d 1 is formed in a convex curved shape having an apex on the rotation center line of the rotation shaft 10. According to the illustrated example, the projecting end (apex) of the oppositely convexly curved portion 31d1 and the rear end surface (the outer surface of the recess 31d) of the base portion 31a are flush with each other.
The oppositely convexly curved portion 31d1 is in point contact with the convexly curved portion 10a at the front end of the rotary shaft 10.

  Then, an annular gap s3 is secured around the facing convexly curved portion 31d1 in the concave portion 31d. The gap s3 functions as a grease (lubricant) storage space.

In addition, the second sun gear 12 is provided integrally rotatably with the first carrier 31 at the center of the front surface of the base portion 31a (see FIG. 6).
According to the illustrated example, the second sun gear 12 is configured of a fixed shaft 31e projecting forward from the center of the front surface of the base portion 31a, and a gear member 12a integrally formed on the outer periphery of the fixed shaft 31e. Be done. The fixed shaft 31e is integrally formed with the base portion 31a. Further, the gear member 12a has a spur gear-like tooth portion over the entire circumference thereof.
The second sun gear 12 can use the fixed shaft 31e and the gear member 12a as one member or separate members.

Then, on the front end surface of the second sun gear 12 (the front end surface of the fixed shaft 31e according to the illustrated example), a convex curved portion 12b is provided which protrudes forward (see FIG. 4).
The convexly curved portion 12b, as described in detail, is composed of a flat surface portion 12b1 having a relatively small area and a curved surface portion 12b2 provided around the flat surface portion.
The flat surface portion 12b1 is a flat surface having a circular shape in a plan view.
The curved surface portion 12b2 is a convex curved surface which is gradually reduced in diameter toward the front and connected to the flat surface portion 12b1.

  In addition, it is also possible to set it as the convex-shaped curved surface diameter-reduced gradually toward the center as another example of the convex curve part 12b, without having the flat surface part 12b1.

The second carrier 32 is provided with a base portion 32a in the same manner as the first carrier 31, and on the rear surface side of the base portion 32a, a plurality of shaft portions 32b (see FIG. 6) projecting backward, A protrusion (the same configuration as the protrusion 31c) at the end of the portion 32b, a recess 32d on the central portion side (see FIG. 4), and an opposing convexly curved portion 32d1 in the recess 32d (see FIG. 4) A gap s4 is secured around the portion 32d1.
The oppositely convexly curved portion 32d1 is in point contact with the flat surface portion 12b1 of the convexly curved portion 12b, as shown in FIG.

Further, a third sun gear 13 (see FIG. 6) on the center side is provided on the front side of the base portion 32a.
Similar to the second sun gear 12, the third sun gear 13 is integrally formed of a fixed shaft 32e protruding from the base portion 32a and a gear member 13a formed on the outer periphery of the fixed shaft 32e (see FIG. See Figure 6).
Then, similarly to the second sun gear 12, a convex curved portion 13b composed of a flat surface portion 13b1 and a curved surface portion 13b2 is formed on the center side of the front surface of the third sun gear 13 (see FIG. 5).

  In addition, the third carrier 33 includes a disk-shaped base portion 33a, and on the rear surface side of the base portion 33a, a plurality of shaft portions 33b that project rearward similarly to the first and second carriers 31 and 32 ( 6) and protrusions (the same configuration as the protrusion 31c) at the end of each shaft 33b. An output shaft 34 is integrally fitted to a central portion of the base portion 33a.

The output shaft 34 is formed in a substantially elongated cylindrical shape, penetrates the front end wall portion 42 of the gear case 40, and exposes the front end side to the outside.
The rear end face of the output shaft 34 is formed in a flat surface shape, and as shown in FIG. 5, contacts with a relatively small area to the convexly curved portion 13b (specifically, the flat surface portion 13b1) of the third sun gear 13. doing.
Then, a gap s5 is secured between the rear end surface of the output shaft 34 and the front end surface of the third sun gear 13 (fixed shaft 32e) around the convex curved portion 13b.

  In FIGS. 1 and 6, reference numeral 35 denotes a sealing material (for example, an O-ring or the like) made of an elastic material, reference numeral 36 denotes a washer, and reference numeral 37 denotes a retaining ring.

The gear case 40 is a substantially bottomed cylindrical member having a front end wall portion 42, and has an inner gear 41 on its inner circumferential surface that meshes with the first to third planetary gears 21, 22, and 23.
An end plate 50 is fitted to the rear end opening of the gear case 40.

  The end plate 50 is a disk-like member for inserting the rotation shaft 10 of the motor 1 loosely in the central portion, and connects the gear case 40 and the case of the motor 1 coaxially and integrally. In FIG. 1, reference numeral 51 denotes a sealing material (for example, an O-ring or the like) made of an elastic material.

Next, the characteristic effects of the planetary gear mechanism 2 configured as described above will be described in detail.
If the rotation shaft 10 of the motor 1 is driven to rotate, this rotational force becomes the first to third sun gears 11, 12, 13, the first to third planetary gears 21, 22, 23, the first to third The speed is reduced by the carriers 31, 32, 33, the internal gear 41, etc., and transmitted to the output shaft 34.
At this time, the front end of the rotary shaft 10 (first sun gear 11) contacts the rear end of the first carrier 31 (see FIG. 2), the front end of the second sun gear 12 and the rear end of the second carrier 32 (see FIG. 4) Contact, the third sun gear 13 front end and the output shaft 34 rear end (see FIG. 5) contact is a relatively small area contact or point contact, and moreover, in the gaps s2 to s5 between them. Since a suitable amount of grease (lubricating oil) is stored, the rotational resistance due to these contacts can be significantly reduced.

Moreover, as shown in FIG. 3, a gap s1 is secured between the backward shaft portion 31b and the opposing surface 50a of each carrier by the above-mentioned contact, and a suitable amount of grease (s2) is provided around s3c. Since lubricating oil) is stored, these can further reduce frictional resistance.
Even if the protrusion 31c at the rear end of the shaft 31b contacts the front surface of the end plate 50 due to wear of each part, a load in the thrust direction, etc., the contact is approximately point contact by the convex curved surface 31c. Thus, the frictional resistance can be reduced to stabilize the rotation.

  Therefore, the geared motor A having the above configuration is suitable for rotating, for example, a wireless antenna and other devices installed outdoors at a relatively low speed in a cold region or the like.

  According to the above embodiment, the three-stage planetary gear mechanism is configured, but as another example, it is possible to configure a single-stage, two-stage, four-stage or more planetary gear mechanism. .

  Further, according to the above embodiment, the convex curved portions 10a and 12b are provided on the front end surface of the sun gear, and the concave portions 31d and 32d and the opposing convex curved portions 31d1 and 32d1 are provided on the rear end surface of the opposing carrier. As the configuration, the configuration may be reversed, and a concave portion and an oppositely convex curved portion may be provided on the front end surface of the sun gear, and a convex curved portion may be provided on the rear end surface of the opposing carrier.

  Further, according to the above embodiment, the rear end surface of the output shaft 34 is formed on the flat surface, but as another example, the rear end surface is also provided with the same configuration as the concave portion 31 d and the oppositely convexly curved portion 31 d 1 Is possible.

  Further, according to the above embodiment, the rotary shaft 10 penetrates the first sun gear 11, and the convex curved portion 10a at the front end of the rotary shaft 10 is in point contact with the opposing convex curved portion 31d1. It is also possible to form the sun gear of the present invention in a bottomed shape so as not to penetrate the rotation shaft, and to provide a convex curved portion at the front end of the bottomed wall portion.

  FIG. 9 shows an application example of the geared motor A according to the embodiment of the present invention. As shown in FIG. 9A, the geared motor A is an electronic device, and can be incorporated in a drive unit (camera unit, open / close cover unit, etc.) of a portable information terminal 100 such as a smartphone. As shown in b), it can be incorporated into the joint drive unit of the robot 200 or the like. The portable information terminal 100 or the robot 200 including the geared motor A according to the embodiment of the present invention can reduce the frictional resistance and can operate smoothly.

  As mentioned above, although the embodiment of the present invention has been described in detail, the specific configuration is not limited to these embodiments, and even if there is a design change or the like within the scope of the present invention. Included in the invention. In addition, the respective embodiments described above can be combined with each other by utilizing the techniques of each other unless there is a contradiction or a problem in particular in the purpose, the configuration, and the like.

1: Motor 2: Planetary gear mechanism 11, 12, 13: first to third sun gears 21, 22, 23: first to third planetary gears 31, 32, 33: first to third carrier 10a , 12b, 13b: convex curved portion 31b: shaft portion 31c: projection 31d, 32d: concave portion 31d1, 32d1: opposing convex curved portion 41: internal gear 50a: opposing surface A: geared motor s1 to s5: gap

Claims (8)

A sun gear, a planetary gear meshed with an outer peripheral tooth portion of the sun gear, a carrier that rotates on the front side of the sun gear and rotatably supports the plurality of planetary gears, and the plurality of planetary gears In a planetary gear mechanism provided with an internal gear meshing on its peripheral side,
A convex curved portion is formed in a substantially convex curved shape on the rotation center side of at least one of the front end surface of the sun gear and the rear end surface of the carrier on the front side of the sun gear. The planetary gear mechanism characterized in that the part is in contact with the other surface with respect to the one surface.   The planetary gear mechanism according to claim 1, wherein an opposing convexly curved portion facing and contacting the convexly curved portion is provided on the other surface.   The planet according to claim 2, wherein a concave portion is provided on the rotation center side of the other surface, and the oppositely convexly curved portion is provided in the concave portion to secure a gap around the oppositely convexly curved portion. Gear mechanism.   The carrier is provided with a shaft portion rotatably supporting the planetary gear, and a gap is secured between a tip end of the shaft portion and a surface opposed to the tip end. Planetary gear mechanism of any one of -3.   The planetary gear mechanism according to claim 4, wherein a protrusion having a substantially convex curved surface shape is provided at a tip end of the shaft portion.   The motor is provided so that rotational force may be transmitted to the said sun gear, The geared motor provided with the planetary gear mechanism in any one of the Claims 1-5 characterized by the above-mentioned.   The electronic device provided with the geared motor in any one of Claims 1-6.   A robot comprising the geared motor according to any one of claims 1 to 6.

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