JPH01164843A - Speed reducing device - Google Patents

Abstract

PURPOSE:To provide a compact speed reduction device having a large speed ratio and to ensure a high load capacity by providing an epicyclic gear mechanism having, as a sun gear, a small diameter gear on a rotor shaft, and a harmonic drive mechanism forming internal teeth in the inner peripheral surface of a flexible gear which is associated with the small diameter gear. CONSTITUTION:The rotation of a motor 1 drives an epicyclic gear A9 engaged with a sun gear 10 so as to rotate an arm 7 through the intermediary of a stationary internal gear 3 as a support member secured to a housing 2, and two epicyclic gears B6 are rotated. Accordingly, the two planetary gears B6 engage with and press internal teeth 5-3 on a flexible gear 5, serving as a wave generator in a harmonic drive mechanism function, and teeth 5-1 meshed with outer peripheral stationary gears engage with the stationary internal gear 3, and teeth meshed with a rotary internal gear engage with a rotary internal gear 4. Further, the flexible internal gear 5 drives an output shaft 12 through the rotary internal gear 4 and an output gear 13 meshed with the latter, the stationary internal gear 3 serving as fulcrum.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Purpose of the Invention [Field of Industrial Application] The present invention relates to the internal structure of a speed reduction device whose input side and output side are coaxial.

[Prior Art] The content and structure of the prior art will be explained with reference to FIGS. 4 and 5.

As is well known, reduction gears with coaxial output shafts require the addition of at least an intermediate position bearing structure to hold the output shaft, making the structure complicated. A planetary gear mechanism (FIG. 4) and a harmonic drive mechanism (FIG. 5), which will be described later, have been devised and put into practical use as speed reducers with a large speed ratio per stage and a simple structure.

FIG. 4 shows an example of a general planetary gear mechanism, in which a sun gear 10 and a planetary gear 9 that engages with the sun gear are in one stage.

In this example, the rotor shaft gear serving as the sun gear 10 is connected to the output shaft 12.
A plurality of planetary gears 9 are rotatably supported by a column 8 which is arranged and fixed on a concentric circle, and is engaged with an arm 7 which is integral with the arm 7 .

The planetary gear 9 also engages with a fixed internal gear 3 fixed to the housing 2 at an outer portion opposite to the sun gear 10, and the sun gear 9 simultaneously engages with the fixed internal gear 3. In this case, it is supported and revolves together with the arm 7, causing the output shaft 12 to rotate.

FIG. 5 shows an example of a so-called harmonic drive mechanism, in which the inner circumferential surface of the flexible gear 5 is suppressed (at this time, the inner peripheral surface of the flexible gear 5 is The shaft D1 portion does not engage due to the difference in the number of teeth between the fixed internal gear 3 and the flexible gear 5.
A spaced apart portion 15 is formed), and the teeth on the outer circumferential side of the suppressing portion are engaged with the fixed internal gear 3, thereby interlocking the fixed internal gear 3.

The flexible gear 5 also engages with a rotary internal gear 4 coaxially adjacent to the fixed internal gear 3 and rotatably disposed, using the fixed internal gear 3 as a support. The shaft output shaft 12 is rotated together with the rotary internal gear 4 via the rotary internal gear support portion 4-1.

This harmonic drive mechanism uses the wave generator 14, which is the key to power transmission, except for low-precision products for hobby use.
However, due to its configuration, it is expensive, and as a general-purpose small speed reduction device, it cannot be said to be practical due to cost constraints.

[Problems to be Solved by the Invention] The present invention provides a reduction gear device in which the input and output shafts are coaxial, which is compact, has a large speed ratio, and can realize a high load capacity without any cost disadvantage. There is something to be gained.

(2) Structure of the Invention [Means for Solving Problems] The speed reduction device of the present invention includes a planetary gear mechanism in which a small diameter gear formed and fixed to the rotor is a sun gear, and a flexible gear mechanism interlocked with the planetary gear mechanism. a harmonic drive mechanism in which internal teeth are formed on the inner circumferential surface of the gear, the planetary gear of the planetary gear mechanism is rotatably supported by a pillar fixed to an arm, and one of the planetary gears has a sun gear; The other gear has two types that mesh with the internal teeth of the flexible gear of the harmonic drive mechanism, and the two types of planetary gears are alternately arranged on one side of the arm or in opposite directions, and one side is interlocked with the output shaft. The rotation-side internal gear of the harmonic drive mechanism has an internal toothed part on its inner surface that meshes with a part of the flexible gear and an output gear that is integral with the output shaft, or has a disc that fixes the output shaft to its end. It is configured such that a shaped support portion is integrally formed therein.

[Function] In the above-mentioned configuration, the planetary gear functions as a wave generator that presses the flexible gear, so effects such as a high speed ratio and high load capacity can be achieved within the compact configuration. bring.

[Embodiments of the invention] The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a cross-sectional view (a) in a direction perpendicular to the direction of arrows and a perspective view (b) from the motor side of an example of a reduction gear device in which the input and output shafts are coaxial according to the present invention. A fixed internal gear 3 is fixed to the inner circumferential surface of the fixed internal gear 3, and a rotatable gear having a number of teeth larger by 2 and having an inner diameter approximately equal to that of the fixed internal gear 3 and coaxially with the fixed internal gear 3. A moving internal gear 4 is installed.

As mentioned above, the number of teeth of both internal gears 3 and 4 is 2 on the rotating side compared to the fixed side.
A flexible gear 5 having the same number of teeth as the fixed internal gear 3 on its outer circumferential surface is coaxially disposed on the inner periphery of the flexible gear 5, and approximately half of the teeth are engaged with both of the internal gears. They are arranged so that they match.

Further, another internal tooth 5-3 having an even number of teeth is formed on the inner peripheral surface of the flexible gear 5, and an arm 7 forming a planetary gear mechanism is fixed to the internal tooth 5-3. One planetary gear B, 6 is rotatably supported by pillar 8 at a position shifted by 180 degrees.
are engaged.

Further, on the back side of the arm 7 is the one planetary gear B.

6, two further planetary gears A in a circumferentially alternating arrangement;
9 is arranged.

The other planetary gears A and 9 are connected to a part of the fixed internal gear 3 on the outer periphery side and to a rotor shaft gear which is the output shaft of the electric motor 1, ie, the sun gear 10 in the planetary gear mechanism, on the inner periphery side. match.

Further, an output gear 13 that is integrated with an output shaft 12 that is rotatably supported by a bearing 11 mounted on the housing 2 is engaged with a part of the internal teeth of the rotary internal gear 4.

The rotation of the electric motor 1 drives planetary gears A and 9 that engage with a sun gear (rotor shaft gear) 10;

9 rotates the arm 7 using the fixed internal gear 3 fixed to the housing 2 as a support, and together with the arm 7, the planetary gears B and 6
, the two planetary gears B and 6 engage and press the internal teeth 5-3 of the flexible gear 5 to function as the wave generator 14 of the harmonic drive mechanism, as described above. The tooth portion 5-1 that meshes with the fixed gear formed on its outer periphery is the fixed internal gear 3.
and the tooth portions that mesh with the rotary internal gear engage with the rotary internal gear 4, respectively.

Using the fixed internal gear 3 as a fulcrum, the flexible gear 5 drives the output shaft 12 via the rotary internal gear 4 and the output gear 13 engaged therewith.

As mentioned above, its structure and function include forming internal teeth 5-3 on the inner peripheral surface of the flexible gear 5, which engage with the planetary gears B and 6, and suppressing the wave generator in the harmonic drive mechanism by this engagement. It is characterized by its functionality.

In addition, Fig. 2 shows that the pillar 8 fixed to the arm 7 of the planetary gear mechanism is
Each of these is another example of being disposed on one side of the arm 7. Therefore, as shown in the figure, a hole is formed in the center of the arm, and the rotor shaft gear 10 is inserted through the hole. Consists of.

FIG. 3 shows yet another example, in which a support portion 4-1 corresponding to the output gear 13 of the above example is integrally formed on the rotary internal gear 4.

-8= [Effects of the Invention] Since the speed reduction device of the present invention has the above-described structure, it has the advantage of being able to easily secure a high speed ratio and a high load capacity in a compact structure.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view (a) of an example of the reduction gear according to the present invention taken in the direction perpendicular to the direction of arrows, and a perspective view (b) of the reduction gear from the electric motor side. FIGS. 2 and 3 are cross-sectional views taken in the right angle direction of another example Figure 4 is a cross-sectional view of an example of a conventional planetary gear mechanism, and Figure 5 is a cross-sectional view (a) of an example of a conventional harmonic drive mechanism in the direction perpendicular to the direction of the arrow (a) and a perspective view from the motor side. It is. Explanation of symbols 1...Electric motor, 1-1...Rotor shaft, 2...Housing. 3... Fixed internal gear, 4... Rotating internal gear, 4-1... Support part, 5... Flexible gear. 5-1...Gear that engages with the fixed internal gear. 5-2...Gear that engages with the rotating internal gear. 5-3 ・Another internal tooth, 6 ・Planetary gear B, 7...arm. 8...Pillar, 9...Planetary gear A, 10...Sun gear. 11... Bearing, 12... Output shaft, 13. Output gear,
14... Wave generator, 15... Separated portion. Di/Wave generator long axis Dj... wave generator short axis Patent applicant Nippon Servo Co., Ltd. = 11- (~r- Procedural amendment form) February 2, 1999

Claims (7)

[Claims] (1) In a speed reduction device that is directly connected to a rotating machine and has an output shaft coaxially arranged with the rotor axis of the rotating machine, a planetary gear whose sun gear is a small diameter gear formed and fixed to the rotor axis. A speed reduction device comprising a gear mechanism and a harmonic drive mechanism in which internal teeth are formed on the inner peripheral surface of a flexible gear for interlocking with the planetary gear mechanism. (2) The planetary gear rotatably supported by the arm of the planetary gear mechanism is characterized by having two types, one of which meshes with the sun gear, and the other meshes with the internal teeth of the flexible gear of the harmonic drive mechanism. A speed reduction device according to claim 1. (3) Claim 1, wherein the two types of planetary gears are alternately relocated along the circumference of the arm.
The speed reduction device according to item 2. (4) Claims 1 to 3, characterized in that the two types of planetary gears are disposed on opposite sides of the arm.
Reduction device as described in Section. (5) The speed reduction device according to any one of claims 1 to 3, wherein the two types of planetary gears are arranged on one surface of the arm. (6) The rotation-side internal gear of the harmonic drive mechanism that interlocks with the output shaft has a disc-shaped support portion integrally fixed to its end. The reduction gear device according to items 5 to 6. (7) The rotation-side internal gear of the harmonic drive mechanism that interlocks with the output shaft is characterized in that the inner gear on its inner surface meshes with a part of the flexible gear and also with the output gear that is integral with the output shaft. A speed reduction device according to claims 1 to 5.