JP5173139B2 - Reducer structure - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention is suitable for a resin speed reducer, and includes a wave generator roller in which a plurality of rollers are rotatably supported along a circumferential direction on a carrier fixed to an input shaft. External teeth are formed that mesh with the outer periphery of the roller, and the inner peripheral surface is deformable in a radial direction so as to be able to roll relative to the outer periphery of the roller. The present invention relates to a structure of a speed reducer configured to decelerate rotation of an input shaft and transmit it to the output shaft by meshing external teeth of a flex ring with internal teeth fixed to a housing.

A conventionally known flexure-meshing gear device called a so-called harmonic drive mechanism includes a rigid circular internal gear (internal gear) and an internal gear provided inside the internal gear. A flex ring made of an external gear having flexibility that is deformed into an oval shape so as to be meshed at two locations and has a number of teeth that is 2n (n is a positive integer) less than the number of teeth of the internal gear And a wave generator configured to fit inside the flex ring and bend into the flex ring oval shape and includes a carrier and a roller rotatably supported by the carrier.
The wave generator has a structure in which a roller is fixed to a flange-shaped carrier by pins, and is a component that transmits an input rotation operation integrally with an input shaft.

One of the reduction gears equipped with the harmonic drive mechanism is the invention of Patent Document 1 (Japanese Patent Laid-Open No. 2005-188740) relating to the application of the present applicant.
In this invention, the circular spline (internal gear) in which the internal teeth are formed, the input side housing, and the external teeth having the same number of teeth as the internal teeth of the input side housing are formed and have flexibility. A flex spline (flex ring), and a wave generator that fits inside the flex spline and bends the flex spline into a substantially elliptical shape to engage the inner splice and the flex spline at two locations on the long axis thereof. The input shaft integrated with the wave generator and the circular spline integrated with the output shaft are supported and connected to each other by bearings, and the center position accuracy of the input and output shafts Can be maintained with high accuracy, so that the rotational operation becomes smooth and the driving efficiency is improved.

JP 2005-188740 A

  The technique of Patent Document 1 has the effect that the rotational position becomes smooth and the driving efficiency is improved by maintaining the center position accuracy of the input and output shafts with high accuracy. "Gap" of the meshing caused by the swinging of the input shaft and insufficient rigidity of the housing occurs at the meshing part of the internal gear with the internal gear, reducing the number of meshing teeth and increasing backlash, thereby transmitting power. There is a situation where problems tend to occur, such as a decrease in efficiency, and there is a need to solve such problems.

  In view of the problems of the prior art, the present invention prevents backlash at the meshing portion of the flex ring and the internal gear by preventing the occurrence of meshing “backlash” due to the swinging of the input shaft and insufficient rigidity of the housing. Another object of the present invention is to provide a reduction gear that avoids a decrease in the number of meshing teeth and improves power transmission efficiency.

The present invention achieves such an object, and engages a wave generator in which a plurality of rollers are rotatably supported along a circumferential direction on a carrier fixed to an input shaft, and internal teeth fixed to a housing. A flex ring deformable in the radial direction in which outer teeth are formed and an inner peripheral surface is brought into contact with the outer periphery of the roller of the wave generator so as to be capable of relative rolling, and the flex ring is connected to an output shaft; A plurality of rollers of the wave generator are pressed against the flex ring to deform the flex ring and mesh the external teeth of the flex ring with the internal teeth fixed to the housing, thereby rotating the input shaft. In a reduction gear configured to decelerate and transmit to the output shaft, the output shaft is rotatably supported via a bearing. A thrust that receives a thrust load acting on the output shaft between an inner surface perpendicular to the output shaft center of the output side housing and a surface perpendicular to the output shaft center of the flange portion formed on the input side of the output shaft. A bearing is interposed, the output housing is made of a resin material, a metal annular nut is screwed onto the inner periphery of the output housing, and the input shaft is mounted on the inner periphery of the metal nut. An input side housing that is rotatably supported via a spigot portion is fitted, and the output side housing and the input side housing are fixed in a form that sandwiches the metal nut. ).

Further, the present invention is characterized in that, in the speed reducer, two or more rollers rotatably supported by the carrier are provided in directions of 180 ° with respect to each other in the major axis direction of the flex ring. (Claim 2 ).
And in addition to this invention, it is preferable to comprise as follows.
That the plurality of rollers, formed by respectively provided two or more in the direction of 180 ° from each other different outer diameters roller in the long axis direction of the flex-ring (claim 3).

According to the present invention, an inner surface perpendicular to the output shaft center of the output side housing that rotatably supports the output shaft via a bearing, and a right angle to the output shaft center of the flange portion formed on the input side of the output shaft. such between the surface, since the interposed thrust bearing for receiving the thrust load acting on the output shaft (claim 1), an inner surface and an output of the deceleration machine output side housing the thrust load acting on the reducer A thrust bearing is installed using the flange surface formed on the input side of the shaft, and the thrust load is received by the output housing through the thrust bearing with a very simple and compact structure. can do.
This eliminates the need for a special thrust bearing and a space for installing the thrust bearing as in the case of a conventional speed reducer, so that the structure of the speed reducer can be easily and miniaturized.
In addition, since the flange portion of the output shaft adjacent to the flex ring and the gear portion of the internal gear is supported by the thrust bearing, the internal gear can be prevented from being displaced by the thrust load, and the meshing stability in the gear portion is improved. To do.

Further, according to the invention according to claim 1, output side an annular nut is screwed to the inner periphery of the housing, spigot joint input side housing for rotatably supported via a bearing input shaft to the nut In the vicinity of the connecting portion of the output side housing with the input side housing, the outer diameter of which must be relatively thin due to the structure being fixed via the screw connection or the screwed engagement of the annular nut As a result, the rigidity in the vicinity of the coupling portion is increased, which contributes to the improvement in the meshing stability of the flex ring and the gear portion of the internal gear.

Further, according to the present invention, since the plurality of rollers rotatably supported by the carrier are provided in the direction of 180 ° with respect to each other in the longitudinal direction of the flex ring (claim 2 ), the plurality of rollers And flex ring contact area is expanded in the circumferential direction, the radius of curvature of the mesh side of the flex ring, the input side housing and the gear portion of the internal gear is increased, and the number of substantial meshing teeth is increased and meshed. The backlash of the part can be reduced, the meshing rate is increased, high torque can be transmitted, and power transmission efficiency is improved. Further, the meshing noise can be reduced by reducing the backlash.
Further, in Patent Document 1, when the number of meshing teeth of the flex ring, the input side housing, and the gear portion of the internal gear is increased, it can be increased only in accordance with the shape of the roller. The number of meshing teeth cannot be increased beyond a certain level even if the force is increased, but in the present invention, the flex ring shape can be changed to an arbitrary shape by adjusting the number of rollers in the long axis direction. Therefore, adjustments such as increasing the number of meshing teeth can be easily performed.
Furthermore, since the number of rollers increases, the axial width of the rollers can be reduced.

Furthermore, in the invention, if the plurality of rollers are configured by providing two or more rollers having different outer diameters in the direction of 180 ° with respect to each other in the major axis direction of the flex ring (Claim 3 ), By changing the diameter, it becomes possible to adjust the distance between the major axes of the flex ring, and optimize the number of meshing teeth and the tooth height of the gear part of the flex ring and the input side housing and internal gear, It can reduce backlash and improve power transmission efficiency.

  The above effects are more prominent by applying the present invention to a resin speed reducer in which an input shaft, an output shaft, a carrier, a plurality of rollers, a flex ring, an internal gear, and housings are made of a resin material. Become.

  Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this example are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only.

(First Reference Example)
1 is a longitudinal sectional view taken along the rotational axis of a resin speed reducer according to a first reference example of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1 in the first reference example, and FIG. FIG. 4 is a cross-sectional view taken along line BB of FIG. 3 in the first reference example.
1 to 4, the resin speed reducer according to this reference example includes an internal gear 5 that is connected to the output shaft 2 and forms internal teeth 5 a, and external teeth having the same modules as the internal teeth 5 a and the same number of teeth. The flex ring 4 formed with 4a and having flexibility and meshed with the external teeth 4a of the flex ring 4, 2n (n is a positive integer), for example, 2 more than the number of teeth of the external teeth 4a The input side housing 6 in which the inner teeth 6a are formed and the flex ring 4 are fitted into the flex ring 4 and bent into a substantially elliptical shape via a roller, and the flex ring 4 is formed at two locations on the long axis portion thereof. A so-called harmonic drive mechanism comprising a wave generator 70 that meshes the external teeth 4a with the internal teeth 6a of the input side housing 6 and the internal teeth 5a of the internal gear 5 is configured.

Reference numeral 3 denotes an output side housing which is fitted to the input side housing 6 by an inlay portion 6z. The output shaft 2 is rotatably supported at the center of the output side housing 3 through two bearings 10 and 23. Has been. A disk-like flange portion 2b is formed on the input side of the output shaft 2, and the internal gear 5 is fixed to the inner peripheral portion of the flange portion 2b as shown in FIGS.
Reference numeral 1 denotes an input shaft rotatably supported at the center of the input side housing 6 via a bearing 11. A pair of carriers 12 before and after the wave generator 70 are integrally provided on the outer periphery of the input shaft 1. ing. The output shaft 2 and the input shaft 1 are arranged coaxially in the output side housing 3 and the input side housing 6.

As shown in FIGS. 2 to 3, the wave generator 70 includes the pair of carriers 12 in which two pairs of rollers 7 are integrally formed on the input shaft 1 at point-symmetrical positions orthogonal to the axis 1 z of the input shaft 1. , 12, and is rotatably supported on a roller shaft 8 installed between the carriers 12, 12 via a bearing 24.
The resin speed reducer presses two points on the inner side of the flex ring 4 by a pair of rollers 7, and the outer teeth 4 a of the flex ring 4 and the inner teeth 6 a and inner teeth of the input side housing 6 are pressed at the pressing points. By meshing with the internal teeth 5a of the toothed gear 5, following the rotation of the wave generator 70 on the input side, moving the pressing point, and meshing the teeth of the flex ring 4 with each gear, the flex ring 4 The output shaft 2 is decelerated and rotated at a reduction ratio determined by the difference in the number of teeth between the outer teeth 4a and the inner teeth 6a of the input side housing 6.

  Further, as shown in FIG. 2, another pair of rollers 7 is rotatably supported between the carriers 12 and 12 with a phase difference of approximately 90 ° from the pair of rollers 7. The elliptical shape of the flex ring 4 is stably maintained by the other pair of rollers 7, and the outer teeth 4 a of the flex ring 4 and the inner teeth 6 a of the input-side housing 6 are in a non-engaged state and become regular. The state can be shifted to the engaged state in a stable manner.

The output shaft 2 includes two bearings 10 and 23 that support the output shaft 2 on the output housing 3.
The hollow part 2a perforated to the outside, that is, the inside of the output-side bearing 10 is formed.
An extension shaft portion 1a is connected to an end portion of the input shaft 1 on the output shaft 2 side so as to extend from the end portion into the hollow portion 2, and the extension shaft portion 1a is connected to the output side. The output shaft 2 is supported so as to be relatively rotatable by an end bearing 9 installed in an inner portion of the bearing 10.

According to the first reference example, the output shaft 2 is formed with the hollow portion 2a drilled to the inside of the outer bearing 10 that supports the output shaft 2 on the output side housing 3, and the output shaft of the input shaft 1 is formed. An extension shaft portion 1a having two side end portions extending into the hollow portion 2a is provided, and the shaft end portion of the extension shaft portion 1a is provided by an end bearing 9 installed at an inner portion of the bearing 10 of the hollow portion 2a. Since the output shaft 2 is supported so as to be relatively rotatable, the end shaft 9 supports the small-diameter extension shaft portion 1a that extends into the hollow portion 2a of the output shaft 2 that extends to the inside of the outer bearing 10 and is drilled. The support shaft at the end of the output shaft 2 side of the input shaft 1 is long and the small-diameter extension shaft portion 1a suppresses the swinging associated with the rotation of the input shaft 1, and the flex ring 4 and the internal gear 5 are made of resin material. Even in this case, the input shaft 1 The occurrence of "play" in the engagement of the gear portion of the flex ring 4 and the internal gear 5 can be suppressed. Further, the rotation of the output shaft 2 is stabilized with the suppression of the swinging of the input shaft 1 due to the formation of the extension shaft portion 1a.
Thereby, the extension shaft portion 1a is provided at the output shaft 2 side end portion of the input shaft 1 and is supported by the hollow portion 2a of the output shaft 2 with the bearing. The number of teeth is maintained normally, and the rotation of the output shaft 2 is stabilized, so that power transmission efficiency can be improved.

(Second reference example)
FIG. 5 is a view corresponding to FIG. 1 showing a second reference example of the present invention, and FIG. 3 is an enlarged view of a portion Z in FIG.
In the second reference example , the output shaft 2 is formed on the input side of the output shaft 2 and the inner surface 3a perpendicular to the output shaft center of the output side housing 3 that rotatably supports the output shaft 2 via bearings 10 and 23. A thrust bearing 20 for receiving a thrust load acting on the output shaft 2 is interposed between the disk-shaped flange portion 2b and a surface 2c perpendicular to the output shaft center. An input shaft 1 is rotatably supported by the input side housing 6 via a bearing 11, and an end of the shaft is rotatably supported inside the output shaft 2 by an end bearing 27.

According to the second reference example , the inner surface 3a perpendicular to the output shaft center of the output side housing 3 and the surface 2c perpendicular to the output shaft center of the disc-shaped flange portion 2b formed on the input side of the output shaft 2 are used. Since the thrust bearing 20 is interposed between the inner surface 3a of the output side housing 3 in the speed reducer and the surface 2c of the flange portion 2b formed on the input side of the output shaft 2 in the speed reducer. A thrust load can be received by the output-side housing 3 via the thrust bearing 20 with a very simple and compact structure in which the thrust bearing 20 is interposed by using the.
This eliminates the need for a special thrust bearing such as a conventional speed reducer and the installation space for the thrust bearing, and allows the structure of the speed reducer to be simplified and miniaturized, thereby reducing the cost of the apparatus.
Further, since the flange portion 2b of the output shaft 2 adjacent to the flex ring 4, the internal gear 5 and the gear portion of the input side housing 6 is supported by the thrust bearing 20, the displacement of the internal gear 5 due to the thrust load can be prevented. Thus, the meshing stability in the gear portion is improved.

In the second reference example , a screw is formed on the outer periphery of the input side housing 6 that rotatably supports the input shaft 1 via the bearing 11, and the inner end of the output side housing 3 is connected to the inner periphery of the end portion. A screw is formed, and the input side housing 6 and the output side housing 3 are fixed by a screw portion 22 in which the male screw and the female screw are screwed together.
By configuring in this manner, the vicinity of the coupling portion between the output side housing 3 and the input side housing 6, which must be relatively thin with a large outer diameter, is structurally coupled by the screw portion 22. The rigidity in the vicinity of the coupling portion is increased, which contributes to improvement in the stability of the meshing between the flex ring 4 and the internal gear 5 and the gear portion of the input side housing 6.
Other configurations are the same as those of the first reference example shown in FIG. 1, and the same members are denoted by the same reference numerals.

(First Embodiment)
FIG. 6 is a view corresponding to FIGS. 1 and 5 showing the first embodiment of the present invention, and FIG. 3 is an enlarged view of a portion Z in FIG.
In the first embodiment, a female screw is formed on the inner peripheral portion of the output-side housing 3, and a male screw of an annular metal nut 25 (the rigidity of the output shaft is improved by using a metal) is formed on the female screw. The nut 25 is fixed by the threaded screw portion 26, the input side housing 6 is fitted to the inner periphery of the metal nut 25 by the spigot portion 6 a, and the input side housing 6 is connected by a plurality of bolts 61. And the output side housing 3 are fixed in such a manner that the metal nut 25 is sandwiched between them.

According to the first embodiment, the annular nut 25 is screwed in the vicinity of the coupling portion between the output side housing 3 and the input side housing 6, which must be structurally thin and relatively thin. By fixing and reinforcing, the rigidity in the vicinity of the coupling portion is increased, which contributes to the improvement of the meshing stability between the flex ring 4 and the internal gear 5 and the gear portion of the input side housing 6.
The other configuration is the same as that of the second reference example (FIG. 5) except for the screw portion 22, and the same members are denoted by the same reference numerals.

( Second embodiment)
FIG. 7 is a front view (viewed in a direction perpendicular to the rotation axis) of the vicinity of the roller support portion of the resin speed reducer according to the second embodiment of the present invention.
In this second embodiment, two rollers 7b and 7b that are rotatably supported by the carrier 12 of the wave generator 70 (see FIG. 1) are arranged in directions of 180 ° with respect to each other in the major axis direction of the flex ring 4. Provided (each may be 3 or more). Further, in the minor axis direction as with the first real施例, it provided one each of the rollers 7a.

According to the second embodiment, the contact range between the two rollers 7b, 7b and the flex ring 4 provided in the direction of 180 ° in the major axis direction is expanded in the circumferential direction, and the flex ring 4 and The radius of curvature on the meshing side of the gear portion of the input side housing 6 and the internal gear 5 is increased, the number of meshing teeth is increased, the backlash of the meshing portion can be reduced, and the number of meshing teeth is increased to transmit power. Efficiency is improved and high torque can be transmitted. Further, the meshing noise can be reduced by reducing the backlash.
In Patent Document 1, although it is possible to increase the number of meshing teeth of the flex ring, the input-side housing, and the gear portion of the internal gear, it can be increased only in accordance with the shape of the roller. However, even if the pressing force of the roller is increased, the number of meshing teeth cannot be increased beyond a certain level.
On the other hand, in the second embodiment, the flex ring 4 can have any shape by adjusting the number of the roller rollers 7b, 7b in the long axis direction. Adjustments such as increasing the number of meshing teeth can be made easily.

( Third embodiment)
FIG. 8 is a front view (corresponding to FIG. 7) in the vicinity of the roller support portion of the resin speed reducer according to the third embodiment of the present invention.
In the third embodiment, rollers having different outer diameters, that is, rotatably supported by the carrier 12 of the wave generator 70 (see FIG. 1), that is, a large-diameter roller 7a and two small-diameter rollers 7b and 7b are combined. Thus, two pairs are provided in the direction of 180 ° with respect to each other in the major axis direction. Further, one roller 7c is provided in the minor axis direction as in the first to second embodiments.

According to the third embodiment, by changing the outer diameter of two pairs of rollers (the large diameter roller 7a and the two small diameter rollers 7b and 7b) provided in the direction of 180 ° with respect to each other in the major axis direction, The distance between the major axes of the ring 4 can be adjusted, and the number of gear teeth and the tooth height of the flex ring 4 and the input side housing 6 and the internal gear 5 can be optimized to reduce backlash. The power transmission efficiency can be improved.
Further, by adjusting the outer diameters of the rollers 7a and 7b in the long axis direction, the range of adjustment of the shape of the flex ring 4 is expanded, thereby making it easy to make adjustments such as increasing the number of meshing teeth.
Other configurations are the same as those of the second embodiment (FIG. 7), and the same members are denoted by the same reference numerals.

( Third reference example)
FIG. 9 is a view corresponding to FIG. 1 showing a third reference example of the present invention.
In this third reference example , the output side portion of the output shaft 2 is rotatably supported on one end side of the output side housing 3 via two bearings 10 and 23, and the input side portion of the output shaft 2 is cylindrical on the input side portion. A cylindrical flange portion 2y is formed and fixed to the outer periphery of the internal gear 5, and the outer periphery of the cylindrical flange portion 2y is rotatable to the other end of the output side housing 3 via a bearing 30 (preferably a thin bearing). I support it.

According to the third reference example, the internal teeth of the output shaft 2 that are easily swayed away from the output side portion of the output shaft 2 supported on the one end side of the output side housing 3 via the bearings 10 and 23. By forming a cylindrical flange portion 2y fixed to the outer periphery of the internal gear 5 at the input side portion of the output shaft 2 in the vicinity of the gear 5 connecting portion, and supporting it on the output side housing 2 via the bearing 30, The support rigidity in the vicinity of the coupling portion of the output shaft 2 to the internal gear 5 is increased, so that the deformation of the internal gear 5 can be suppressed, the rotation of the internal gear 5, the rotation of the internal gear 5 and the flex ring 4. The meshing of the gear portion is stabilized and the power transmission efficiency is improved.
Other configurations are the same as those of the first reference example (FIG. 1), and the same members are denoted by the same reference numerals.

  According to the present invention, the backlash at the meshing portion of the flex ring and the internal gear is reduced and the meshing rate is reduced by preventing the occurrence of meshing “play” due to the swinging of the input shaft and insufficient rigidity of the housing. Can be provided, and a reduction gear with improved power transmission efficiency can be provided.

It is a longitudinal cross-sectional view which follows the rotating shaft center of the resin speed reducer which concerns on the 1st reference example of this invention. It is sectional drawing which follows the AA line of FIG. 1 in the said 1st reference example. FIG. 10 is an enlarged view of a Z portion in FIGS. 1, 5, 6, and 9 in the first reference example. It is sectional drawing which follows the BB line of FIG. 3 in the said 1st reference example. FIG. 3 is a diagram corresponding to FIG. 1 illustrating a second reference example of the present invention. FIG. 6 is a view corresponding to FIGS. 1 and 5 showing a first embodiment of the present invention. It is a front view (figure looked at right angle to the rotating shaft center) of the roller support part vicinity of the resin speed reducer which concerns on 2nd Example of this invention. FIG. 8 is a view corresponding to FIG. 7 showing a third embodiment of the present invention. FIG. 6 is a diagram corresponding to FIG. 1 and showing a third reference example of the present invention.

DESCRIPTION OF SYMBOLS 1 Input shaft 1a Extension shaft part 2 Output shaft 2a Hollow part 2b Flange part 2y Cylindrical flange part 3 Output side housing 4 Flex ring 4a External tooth 5 Internal gear 5a Internal tooth 6 Input side housing 6a Internal tooth 6z Inner part 7, 7a, 7b, 7c Roller 9 End bearing 10, 11, 23 Bearing 12 Carrier 20 Thrust bearing 22, 26 Threaded portion 24 Bearing 25 Nut 30 Bearing 70 Wave generator

Claims (3)

A wave generator that rotatably supports a plurality of rollers along the circumferential direction on a carrier fixed to the input shaft, outer teeth that mesh with inner teeth fixed to the housing, and an inner peripheral surface A flex ring that is deformable in a radial direction is brought into contact with an outer periphery of the roller of the wave generator so as to be capable of relative rolling. The flex ring is connected to an output shaft, and the plurality of rollers of the wave generator are connected to the flex generator. The rotation of the input shaft is decelerated and transmitted to the output shaft by engaging the outer teeth of the flex ring and the inner teeth fixed to the housing while deforming the flex ring by being pressed against the ring. In the configured reducer,
Between an inner surface perpendicular to the output shaft center of the output side housing that rotatably supports the output shaft via a bearing, and a surface perpendicular to the output shaft center of the flange portion formed on the input side of the output shaft. A thrust bearing for receiving a thrust load acting on the output shaft is interposed, the output housing is made of a resin material, and a metal annular nut is screwed to the inner periphery of the output housing, An input side housing that rotatably supports the input shaft via a bearing is fitted to an inner periphery of the metal nut via an inlay portion, and the output side housing and the input side housing are sandwiched by the metal nut. A structure of a speed reducer characterized by being fixed in form . 2. The structure of a speed reducer according to claim 1, wherein a plurality of rollers rotatably supported by the carrier are provided in a direction of 180 degrees with respect to each other in the major axis direction of the flex ring . The speed reducer structure according to claim 2, wherein the plurality of rollers are provided with two or more rollers having different outer diameters in a direction of 180 ° with respect to each other in the longitudinal direction of the flex ring .

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