JP2003194158A - Reduction gear adopting marvelous gear mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optimal support structure for a carrier supporting a plurality of planetary gears, in a reduction gear adopting a so-called 'marvelous' gear mechanism. <P>SOLUTION: In the reduction gear using the so-called 'marvelous' gear mechanism, a sun gear is used as an input and engaged via planetary gears with a fixed gear and a movable gear which have different numbers of internal teeth, and the rotation of the shaft of the movable gear is used as an output. The movements of the movable gear in thrust and radial directions are regulated by the movable gear shaft and an open end face part of the movable gear and a member for supporting the rotation of a carrier supporting the plurality of planetary gears and for regulating the radial movement is provided only on the sun gear side. On the movable gear shaft side of the carrier, regulation of the radial movement is not effected while regulation of the movement in the thrust direction is effected using a convex shape being ring-shaped on an opposite face and circumferentially divided into a plurality of sections. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed reducer to which a so-called mysterious gear mechanism which is small and has a large reduction ratio is applied. 2. Description of the Related Art A reduction gear having a sun gear as an input, meshing with a fixed gear and a movable gear having internal teeth having different numbers of teeth via a planetary gear, and outputting the rotation of the movable gear shaft as an output. 3
It is known as a K-type wonder gear mechanism. The structure is described in detail with reference to the mechanism diagram of FIG. 2. A is a sun gear fixed to a drive shaft such as a motor output shaft, B is a planetary gear, and C is a sun internal gear meshing with the planetary gear. Fixed. D is a sun internal gear that has a different number of teeth from the sun internal gear C and meshes with the planetary gear, and is a movable driven shaft. S is a carrier that holds one or more planetary gears at a predetermined center distance to each sun gear. With the above configuration, the gear meshes with the sun gear A
And the planetary gear B, the planetary gear B and the sun internal gear (fixed) C, and the planetary gear B and the sun internal gear (movable) D by appropriately transposing the standard involute tooth profile. Further, the gear can be designed as a well-known spur gear or helical gear. In particular, a helical gear having an increased mesh ratio is one means for reducing noise. Except for the fixed sun internal gear C, the structure is supported so as to rotate while receiving forces in the radial direction and the thrust direction, respectively. [0006] From the above, there is provided a reduction gear applying a 3K type mysterious gear mechanism at a reduction ratio represented by the following equation. Sun gear A: Number of teeth Z a Sun internal gear C: Number of teeth Zc Sun internal gear D: Number of teeth Zd Reduction ratio = {(1 + Zc / Za) / (1-Zc / Zd)} In the structure of the above-mentioned mechanism, the gears other than the fixed sun internal gear C rotate while receiving the radial and thrust forces, respectively, and hold a plurality of planetary gears. The career to do is
Since the orbit revolves at the support portion in the radial direction and the thrust direction because of its orbit, loss, noise, vibration, and the like are generated. [0008] It is an object of the present invention to provide an optimum radial and thrust rotation support structure for a carrier that revolves while holding a plurality of planetary gears. In order to achieve the above object, the present invention provides a sun gear as an input, and meshes with a fixed gear and a movable gear having internal teeth having different numbers of teeth via a planetary gear. In addition, in a reduction gear applying a so-called mysterious gear mechanism that outputs the rotation of the movable gear shaft, the thrust and radial movement of the movable gear are regulated by the open end surfaces of the movable gear shaft and the movable gear. A member for supporting the rotation of the carrier supporting a plurality of gears and for regulating the movement in the radial direction is the sun gear side, and the movable gear shaft side of the carrier does not perform the regulation in the radial direction, The thrust direction is regulated by using a speed reducer characterized in that the opposing surface is formed in a ring shape and a plurality of circumferentially divided convex shapes. FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIGS. Reference numeral 2 denotes a spacer formed with the fixed internal teeth 2c, which is a coupling member centered on an output shaft 3 of a motor (not shown) which corresponds to an input. Reference numeral 4 denotes a sun gear, which is fixed as a pinion gear to a substantially end portion of the output shaft 3 by press-fitting, bonding, or the like. Reference numeral 6 denotes a plurality of planetary gears, and reference numerals 5 and 7 denote intermediate plates A and B, respectively, on which the planetary gears are arranged and supported. In the embodiment of the present invention, the same components are arranged in three equal parts, but two to four components may be used. An intermediate plate support 7b for holding the planetary gear 6 so as to be sandwiched between the intermediate plate B and the intermediate plate A is formed on the intermediate plate B,
The whole constitutes a carrier. Reference numeral 8 denotes a substantially cup-shaped movable internal tooth, which has an internal tooth 8a formed on an inner peripheral portion thereof so as to mesh with a meshing gear 6b of the planetary gear 6, and supports an axial end in an open end face in a radial thrust direction. Receiving portion 8b is provided. Reference numeral 9 denotes a gear output shaft, one end of which is fixed to the center of the movable gear by press-fitting or insert molding, and transmits the rotation and torque of the movable gear 8 to the outside. Reference numeral 1 denotes a gear cover having a bearing 1a for supporting the gear output shaft 9 and an engaging portion 1b for positioning and fixing the gear output shaft 9 to the spacer 2. The movable gear is shielded to prevent foreign matter from entering. In addition, it has holes and taps for mounting engagement portions and mounting screws (not shown). With the above-mentioned components, the carrier rotates (revolves) in a space surrounded by the spacer 2 and the movable internal teeth 8. The support of the carrier requires the radial and thrust directions, and in particular, a minimum necessary and optimum support structure in consideration of mechanical loss, noise, vibration, and the like will be described below. First, in the radial direction, if the meshing portions of the respective gears are removed, specifically, the intermediate plate A on the spacer side between the spacer 2 and the carrier, and the intermediate plate A between the movable internal teeth 8 and the movable internal teeth side of the carrier. This is a support structure for the plate B. First, the accuracy of the center distance between the meshing gear 6a of the sun gear 4 and the planetary gear 6, and the center distance between the meshing gear 6a and the fixed internal teeth 2c, that is, the positioning of the carrier in the radial direction is determined by the sun gear 4 formed on the spacer 2. The intermediate plate receiving portion 2b having a diameter larger than the tooth tip circle diameter and the intermediate plate A spigot portion 5a provided on the intermediate plate A are used. Next, the planetary gear 6
The radial engagement between the meshing gear 6b of the movable gear 8 and the internal teeth 8a of the movable gear 8 is determined at the portion having a diameter larger than the root circle diameter of the fixed internal teeth 2c and the internal teeth 8a. This is performed by providing the receiving portion 8b. In addition to the above, the spigot portion 7c of the intermediate plate B
FIG. 3 shows another configuration example in which the spigot portion 8d of the movable gear 8 corresponding to the above is provided to form a radial receiver. Compared with FIG. 1 which is an embodiment of the present invention, the configuration is intended to further stabilize the revolving motion of the carrier by increasing the number of radial receiving portions. However, when a prototype was actually evaluated, it was confirmed that the variation in the efficiency was about 3.5 times and the variation in the noise was about 1.1 times, and the effect of stabilizing the orbital motion was not seen. In the prototype, the voltage, load, and rotation speed were changed, and 100 or more measurements were performed, and the results of obtaining the variation (standard deviation) are shown in Table 1 below. [Table 1] This is because the meshing gear 6b of the planetary gear 6
In order to obtain the accuracy of the center-to-center distance between the movable gear 8 and the internal teeth 8a, it is necessary to reduce the positional accuracy (coaxiality) at the time of rotation in the radial fitting, but in the configuration shown in FIG. The increase in the number of the radial receiving portions, in addition to the accuracy of the coaxiality of the internal teeth 8a of the movable gear 8 and the receiving portion 8b, also increases the movable gear 8
As in the receiving portion 8b, the coaxiality accuracy of the spigot portion 8d and the coaxiality accuracy of the meshing gear 6b of the planetary gear 6 and the coaxiality accuracy of the spigot portion 7c of the intermediate plate B are added. Had become worse. Next, in the thrust direction, the planetary gear 6
It is desirable to reduce the mechanical sliding loss by a structure in which the shaft of the sun gear does not tilt with respect to the shaft of the sun internal gear. In the present invention, each of the spacer 2 facing the thrust direction surface of the carrier and the movable gear 8 has a carrier receiving convex portion 2f and a carrier receiving convex portion 8c each having a ring shape and divided into a plurality of pieces in the circumferential direction. 1 is shown in the embodiment of FIG. FIGS. 4 and 5 show an embodiment in which these protrusions are provided on the intermediate plate A and the intermediate plate B on the thrust surface of the carrier itself to obtain the same effect. Further, the above-described intermediate plate A spigot portion 5a is provided with a plurality of recesses as shown in FIG. 5 to reduce the contact portion with the intermediate plate receiving portion 2b, thereby reducing the mechanical loss in the radial direction. it can. The sun gear is input, the fixed gear and the movable gear having internal teeth having different numbers of teeth are meshed with each other via a planetary gear, and the rotation of the movable gear shaft is output as a so-called mystery. In a reduction gear to which a gear mechanism is applied, the movement of the movable gear in the radial direction is restricted by the movable gear shaft and the opening end face of the movable gear, and the member that regulates the movement in the thrust direction is a thrust surface on the outer periphery of the fixed gear. At the same time, the carrier for supporting the plurality of planetary gears is limited only to the sun gear side for regulating the movement in the radial direction, and the carrier is not regulated in the radial direction on the movable gear shaft side of the carrier. To prevent the position accuracy from deteriorating at the time of revolution, the thrust direction can be regulated by providing a ring-shaped and circumferentially divided convex shape on the opposing surface to reduce mechanical loss, noise, vibration, etc. It becomes an optimal support structure.

[Brief description of the drawings] FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2 is a mechanical diagram of a mysterious gear. FIG. 3 is a cross-sectional view showing another embodiment. FIG. 4 is a longitudinal sectional view of a carrier. FIG. 5 is a plan view of a carrier. [Explanation of symbols] A sun gear B planetary gear C Sun internal gear (fixed) D Sun gear (movable) 1 Gear cover 1a Bearing part 1b Engagement part 2 room 2a Spacing part 2b Intermediate plate receiving part 2c fixed internal teeth 2d cover receiving part 2e Movable gear receiving part 2f Carrier receiving projection 3 Motor shaft 4 Pinion (sun gear) 5 Intermediate plate A 5a Intermediate plate A spigot part 5b Intermediate plate A convex 6 planetary gear 6a meshing gear 6b mesh gear 7 Intermediate plate B 7a Intermediate plate B hole 7b Intermediate plate support 7c Intermediate plate B spigot part 7d Intermediate plate B projection 8 Movable internal teeth 8a Internal teeth 8b Receiving part 8c Carrier receiving projection 8d Movable gear spigot 9 Gear output shaft

Claims (1)

Claims: 1. A sun gear is input, meshed with a fixed gear having internal teeth having different numbers of teeth and a movable gear via a planetary gear, and the rotation of the movable gear shaft is output. In a reduction gear applying a so-called mysterious gear mechanism, the thrust and radial movement of the movable gear are restricted by the open end surfaces of the movable gear shaft and the movable gear, and the rotation of the carrier supporting a plurality of the planetary gears is supported. The member for regulating the movement in the radial direction is the sun gear side, and the radial direction is not restricted on the movable gear shaft side of the carrier. A speed reduction device characterized in that the reduction is performed in a convex shape divided into a plurality in the circumferential direction.