JPH0592557U - Resin harmonic drive speed reducer - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To reduce the manufacturing cost by making the entire speed reducer consisting of a harmonic drive mechanism compact. [Structure] The flexspline 4 of the harmonic drive speed reducer is molded of polyamide resin, and the wave generator that rotates by the input shaft is composed of two cylinders 10 integrally molded of polyacetal resin. The flexspline 4 and its rotation transmission are A notch is provided on one side of the receiving output shaft 8 and a protruding arm that engages with the notch is provided on the other side to transmit rotation.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a harmonic drive speed reducer for high speed reduction.

[0002]

[Prior Art]

 A conventional harmonic drive is made by making a ring-shaped flexspline from a metal material, bending it into a non-circular shape with an elliptical wave generator, and rotating it while engaging a fixed internal gear with more teeth than the flexspline. Then, the output shaft integrated with the rotating internal teeth is rotated by engaging with the rotating internal teeth having the same number of teeth as the flexspline.

[0003]

[Problems to be solved by the device]

 When the flexspline of the harmonic drive is made of a metal material such as phosphor bronze, the wave generator has a complicated structure that incorporates a bearing, and it is transmitted that the flexspline that elastically deforms and the rotating internal gear that is integral with the output shaft are engaged. Due to the problems of torque and noise, high precision is required, and the production cost is relatively high.

The present invention has been made to solve this problem, and an object thereof is to provide an inexpensive harmonic drive having a simple structure by utilizing the flexibility and slidability of resin. To provide a speed reducer.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the feature of the present invention is to flexibly rotate a ring-shaped flexspline 4 which rotates while partially meshing with a fixed internal gear of a harmonic drive speed reducer, as shown in FIG. Made of a flexible resin, a notch 14 is provided in the flexspline, and a protruding arm 12 that engages with the notch is formed in the output shaft 8 of FIG. Two cylinders are provided on the rotating body, and the cylinders serve as a wave generator to deform and rotate the flexspline 4 into an elliptical shape.

As shown in FIG. 3, two cylinders 10 are fixed or rotatably provided on an end face of a warm wheel 2 of a speed reduction mechanism including a worm 1 and a worm wheel 2 to form a wave generator. Alternatively, as shown in FIG. 4, the cylinder 10 may be fixed to each planetary gear of the capstan reduction mechanism having the two planetary gears 16 or may be rotatably provided to form a wave generator. It is possible.

[0007]

[Action]

 As shown in FIGS. 3 and 4, the worm wheel 2 or the planetary gear 16 is rotated by the worm 1 or the sun gear 15 as an input shaft, and the cylinder 10 provided on the worm wheel or the planetary gear is the flexspline 4. Deform and rotate at reduced speed. Since the protruding arm 12 of the output shaft 8 is fitted in the notch 14 of the flexspline 4, the rotation of the flexspline 4 that is decelerated while elastically deforming is transmitted to the output shaft 8 via the protruding arm 12. .

The fixed internal gear 5 and the outer tooth 11 of the flexspline 4 are usually used with a large difference of two. However, the flexspline outer tooth 11 is negatively displaced by about ½ of the module to improve the tooth height. It enables smooth rotation and transmission of high torque without shortening.

[0009]

【Example】

 The speed reducer of the present invention will be described based on an embodiment shown in the drawings. FIG. 1 shows an output shaft 8 of the speed reducer of the present invention. A disk 13 is provided at one end of the output shaft 8, and a protruding arm 12 projects from the disk, and these are integrally molded of polyacetal resin.

The flex spline 4 in FIG. 2 is an external gear having a ring-shaped notch 14, and is made of polyamide resin. The external teeth 11 are negatively dislocated by 1/2 of the module. The embodiment of FIG. 3 is a sectional view of a speed reducer combined with a worm. The worm 1 and the worm wheel are housed inside an upper case 6 and a lower case 7. The worm 1 is an input shaft, and its rotation is decelerated and transmitted to the worm wheel 2. Two cylinders 10 are integrally formed on the worm wheel 2 with polyacetal resin. These two cylinders act as a wave generator and bend the flexspline 4 into an elliptical shape for rotation. Since the flexspline 4 rotates by a difference in the number of teeth from the fixed internal gear 5, the rotation of the flexspline 4 is greatly reduced with respect to the rotation of the worm wheel 2.

Since the worm wheel 2 is rotatably inserted into the fixed shaft 3 provided upright on the lower case 7, and the fixed shaft 3 is inserted into the fitting hole 9 provided in the shaft center of the output shaft 8, the worm wheel is provided. 2, the flexible spline 4, and the output shaft 8 can be easily positioned coaxially. Since the cylinder 10 as the wave generator is made of polyacetal resin, the flexspline 4 is made of polyamide resin, and the protruding arm 12 of the output shaft 8 is made of polyacetal resin, mutual slidability is very good.

In the embodiment, the rotation of the input shaft is decelerated and transmitted to the rotating body on which the cylinder as the wave generator is projected. However, the rotation of the input shaft is directly transmitted to the rotating body on which the cylinder as the wave generator is projected. You may inform. The embodiment shown in FIGS. 4 and 5 is a speed reducer in which a capstan mechanism is combined, and a brass sun gear 15 is fixed to an input shaft. A cylinder 10 having a radius obtained by subtracting the thickness of the flexspline 4 from the radius of the planetary gear tooth circle is integrally formed on the planetary gears 16 of two sets by polyacetal resin. The flexspline 4 is the same as that shown in FIG. 2, and the wall thickness excluding the teeth is thinned to about 0.5 to 1.0 mm for flexibility. In order to make the entire device compact, the fixed internal gear 5 of the capstan mechanism and the harmonic mechanism is common and molded with polyacetal resin. The cylinder 10 provided on the end faces of the two planetary gears 16 functions as a wave generator, and bends the flexspline 4 into an elliptical shape to rotate it. Since the flexspline 4 rotates by the number of teeth difference from the fixed internal gear 5, the rotation of the flexspline 4 is significantly reduced with respect to the revolution of the planetary gear 16. The flexspline 4, the fixed internal gear 5, the sun gear 15, and the planetary gear 16 are accommodated inside the upper case 6 and the lower case 7, and the rotation of the flexspline 4 is transmitted to the output shaft 8 via the protruding arm 12. introduce. This embodiment is a combination with a capstan mechanism, and the input shaft 20 and the output shaft 8 can be arranged on the same axis.

[0013]

[Effect of the device]

 As described above, the present invention utilizes the slidability and flexibility of the resin and replaces the conventional wave generator with a ball bearing with a complicated structure with a complicated structure with a resin made of two cylinders. Since members are used, the structure of the entire device is simple and compact, the manufacturing cost is greatly reduced, and a high reduction ratio can be obtained by combining another reduction mechanism and harmonic drive reduction mechanism. Play.

[Brief description of drawings]

FIG. 1 is a perspective view of an output shaft of the present invention,

FIG. 2 is a perspective view of the flexspline of the present invention,

FIG. 3 is a sectional view of an apparatus according to an embodiment of the present invention,

FIG. 4 is a view corresponding to FIG. 3 of a device according to another embodiment of the present invention,

5 is a sectional view taken along line VV of FIG.

[Explanation of symbols]

1: worm, 2: worm wheel, 3: fixed shaft,
4: Flexspline, 5: Fixed internal gear, 6: Upper case, 7: Lower case, 8: Output shaft, 9: Fitting hole, 10: Cylinder (wave generator), 11: External tooth, 12: Protrusion Arm, 14:
Notch, 15: sun gear, 16: planetary gear, 20: input shaft

Claims (5)

[Scope of utility model registration request] 1. A case comprising a fixed internal gear (5) fixed to a case (6, 7) and external teeth (11) having fewer teeth meshing with the fixed internal gear than the fixed internal gear. A rotating body comprising a ring-shaped resin flexspline (4) and two cylinders (10) arranged inside the flexspline and bending the flexspline into a non-circular shape as a wave generator (10) ( 2), an input shaft (1, 20) for rotating the rotating body in the previous period, and an output shaft (8) that is received by the case and receives rotation transmission from the flexspline. A resin harmonic drive reduction gear characterized in that a notch (14) is formed on one side of the output shaft, and a protruding arm (12) that engages with the notch is formed on the other side. 2. The involute tooth profile of the intermeshing fixed internal gear (5) and the flexspline external tooth (11), and the flexspline external tooth has a negative shift of 1/2 of the module. 1. The resin harmonic drive reduction gear described in 1. 3. A worm (1) as an input shaft and a worm wheel (2) that meshes with the worm are provided, and two cylinders (10) are fixed or rotatable on the end face of the worm wheel in the previous period. The resin-made harmonic drive speed reducer according to claim 1. 4. A sun gear (1) fixed to an input shaft (20).
5), two planetary gears (16) that mesh with both the first-term fixed internal gear (5) and the first-term sun gear are provided, and the columnar (10) is fixedly or rotatably provided on the first-stage planetary gear. The resinous harmonic drive speed reducer according to claim 1. 5. A flexspline (4) and a planetary gear (1)
5. A resin harmonic drive reduction gear according to claim 4, wherein 6) is engaged with a common fixed internal gear (5).