TW201414937A - Harmonic gear unit having input bearings - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a harmonic gear unit having input bearings, which is provided with an input shaft supported by a bearing device easy to manufacture and assemble. SOLUTION: A harmonic gear unit (1), which uses a first input bearing (7) and a second input bearing (8) to support the input shaft (6) of a built-in harmonic gear device (5). Since the input shaft (6) is fixed to the position in the axial direction of the harmonic generator (16) installed herein, the assembly work of motor is very simple. The annular convex portion (15c) of a flexible external gear (15) is clamped by the bearing housing (21) of the second input bearing (8) that supports the input shaft (6), and then securely locked and fixed to the output disc (4) by using fastening bolts (22). There is no need to perform processing of cutting threads on the annular convex portion (15c) or processing of recessed portions and the like, a simple structure can be used to constitute the fixation device for fixing the bearing device of the input shaft (6) and the flexible external gear (15) to the output disc (4).

Description

Harmonic gear unit with input bearing

The present invention relates to a harmonic gear unit having an input bearing that can simply assemble a motor.

As a harmonic gear unit having an input bearing, a unit type harmonic gear device having a cup-shaped flexible externally toothed gear disclosed in Patent Document 1 is known. In the unit type harmonic gear device, an end face of the rigid cam plate of the harmonic generator is formed with an input shaft, and a shaft portion is formed at the other end surface of the rigid cam plate. The input shaft is supported by the first bearing attached to the end plate of the unit casing, and the front end of the shaft portion on the opposite side is the first input by the disc-shaped convex surface attached to the flexible externally toothed gear. The bearings are supported.

With the pair of input bearings, the harmonic generator is fixed in the axial direction, and the rigid internal gear and the harmonic generator are positioned in the axial direction. Therefore, when the unit type harmonic gear device is coupled to the motor shaft of the motor to constitute the actuator, the motor shaft only needs to be coupled to the input shaft to be fixed, and the assembly work is very simple.

Further, in the unit type harmonic gear device of Patent Document 1, the end surface of the disk-shaped convex surface of the cup-shaped flexible externally toothed gear has a concave portion for bearing mounting, and the other end surface is integrally formed with the output shaft. . By simplifying the structure and reducing the number of parts, the assembly work can be easily performed.

Patent Document 2 discloses that the wave gear device and the motor are integrated The actuator formed by the chemical. In the wave gear device incorporating the actuator, the annular convex portion of the cup-shaped flexible externally toothed gear is screwed to the center through hole of the outer casing end plate from one direction along the axis of the device. . The annular bearing is press-fitted to the convex portion from the same direction along the axis of the device, and a bearing is mounted on the bearing. Further, the motor shaft and the input shaft of the wave gear device are formed as a single hollow shaft. One end of the hollow shaft is supported by a bearing to which a bearing is mounted. The midway portion of the hollow shaft in the axial direction is supported by a bearing mounted on a partition wall for separating the wave gear device from the motor.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] JP-A-2002-21948

[Patent Document 2] JP-A-2002-243000

In the unit type harmonic gear device disclosed in Patent Document 1, a concave portion for bearing mounting or the like is formed on a convex surface of a flexible externally toothed gear manufactured by cutting. Therefore, the processing time of the flexible externally toothed gear increases. In the actuator disclosed in Patent Document 2, the annular convex portion of the cup-shaped flexible externally toothed gear is spirally fixed to the center through hole of the outer casing end plate in the direction of the device axis, and the ring The bearing is press-fitted to the convex portion from the same direction. Therefore, the bearing portion becomes longer in the axial direction, which is disadvantageous for the configuration in which the device is to be reduced in the axial direction. In addition, due to the need Since the convex portion having the screw portion fixed to the end plate is processed, the processing time of the flexible externally toothed gear is also increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a harmonic gear unit having an input bearing whose input shaft is supported by an input bearing device that is easy to manufacture and assemble.

In order to solve the above problems, a harmonic gear unit having an input bearing of the present invention has a cylindrical casing, an end plate fixed to an input side open end of the cylindrical casing, and an output disc for The freely rotating state is mounted on the output side open end of the cylindrical casing; the cup type harmonic gear device is incorporated in the inside of the cylindrical casing; and the input shaft extends through the center through hole formed in the end plate a fixing device for locking and fixing the cup-shaped flexible externally toothed gear of the harmonic gear device to the output disk; and a first input bearing and a second input bearing for supporting the input shaft; The flexible externally toothed gear includes a ring-shaped convex surface that is superposed on the inner end surface of the output disk toward the end plate side, and the fixing device includes a bearing housing facing the aforementioned An annular end surface on the end plate side of the annular convex surface overlaps the coaxial circle And a plurality of fastening bolts that are locked to the output disc by the bearing housing, and the input shaft includes a hollow shaft portion and a motor shaft connection a shaft mounting hole; a solid shaft portion protruding from the blocking shaft end portion of the hollow bearing portion on the bearing housing side toward the inside of the bearing housing, and the harmonic generator of the harmonic gear device has: The input shaft, a rigid cam plate attached to an outer circumference of the hollow shaft portion of the input shaft, and a wave bearing attached to an outer peripheral surface of the rigid cam plate, wherein the first input bearing is attached to the center through hole of the end plate Between the inner circumferential surface and the outer circumferential surface of the hollow shaft portion, the second input bearing is mounted between the inner circumferential surface of the bearing housing and the outer circumferential surface of the solid shaft portion.

The input shaft of the harmonic generator is supported by the first input bearing and the second input bearing on the input side portion and the output side portion. Therefore, the harmonic generator is fixed to the axial direction by the first and second input bearings. When the motor is assembled, it is not necessary to substantially perform the work of positioning the harmonic generator in the axial direction.

Further, the annular convex surface of the flexible externally toothed gear is sandwiched between the output disk and the bearing housing. The above three members are locked and fixed by fastening bolts in this state. The annular convex surface does not require thread cutting or machining of the concave portion of the bearing. Therefore, it is possible to suppress an increase in the processing time of the flexible externally toothed gear. Further, since the three members are locked together by the fastening bolts, the three-member fixing device can be configured with a small number of parts. Therefore, it can be obtained by being easy to make and The assembled bearing device supports the input shaft 6 with a harmonic gear unit of the input bearing.

Here, the three members can be assembled with good precision by the following procedure. The center through hole of the annular convex surface of the flexible externally toothed gear and the center through hole formed in the output disk are formed as through holes having the same inner diameter. Further, the press-fit cylinder that is press-fitted to the center through-hole of the annular convex surface and the center through-hole of the output disk is integrally formed with the bearing housing. As described above, the three members can be locked and fixed by pressing the cylinder so as not to form an eccentric core.

Hereinafter, a harmonic gear unit according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1(a) is a longitudinal sectional view showing a state in which the harmonic gear unit of the present embodiment is assembled with a motor. Fig. 1(b) is an end view of the output side.

The harmonic gear unit 1 includes a cylindrical casing 2, an end plate 3 fixed to the input side open end 2a of the cylindrical casing 2, and an output disc 4 that is rotatably mounted. The output side open end 2b on the opposite side of the cylindrical casing 2.

A cup-type harmonic gear device 5 is incorporated in the cylindrical casing 2, the end plate 3, and the output disk 4. Further, a center through hole 3a is formed in the end plate 3, and the input shaft 6 is inserted into the center through hole 3a in a coaxial state.

The input shaft 6 is freely rotatable by the first input bearing 7 The state is supported. The first input bearing 7 is attached to the inner peripheral surface of the center through hole 3a of the end plate 3. Further, the input shaft 6 is supported inside the harmonic gear unit 5 by the second input bearing 8 in a freely rotatable state. The motor 10 is assembled coaxially by the annular assembly flange 9 on the outer end surface 3b of the end plate 3. The motor shaft 10a of the motor 10 is coupled and fixed coaxially with the input shaft 6. The rotary actuator A is constituted by the motor 10 and the harmonic gear unit 1.

When the motor 10 is rotationally driven, the motor rotation is decelerated by the harmonic gear device 5, and the deceleration rotation is extracted by the output disk 4. A member (not shown) that is fixed to the load side of the output disk 4 is rotationally driven.

The structure of each part of the harmonic gear unit 1 will be described in detail. The portion of the cylindrical casing 2 whose input side open end 2a is formed is a large diameter flange portion. An outer peripheral side portion of the end plate 3 having a disk shape as a whole is fixed to the annular end surface of the large-diameter flange portion by a fastening bolt 11. The output disk 4 is attached to the output side open end 2b of the cylindrical casing 2 in a freely rotatable state by the crossed roller bearing 12. The outer ring 12a of the crossed roller bearing 12 is fixed to the annular end surface of the output side open end 2b of the cylindrical casing 2 by a fastening bolt 13. Inside the outer ring 12a, the output disk 4 is disposed coaxially. The outer peripheral portion of the output disk 4 functions as an inner wheel of the crossed roller bearing 12. That is, the circular outer peripheral surface of the output disk 4 is integrally formed with the inner wheel side raceway surface 12c of the roller 12b.

The harmonic gear device 5 includes a ring-shaped rigid internally toothed gear 14, a cup-shaped flexible externally toothed gear 15, and a harmonic generator 16. just The internal tooth gear 14 is fixed to an inner peripheral surface portion of the input side open end 2a of the cylindrical casing 2. The flexible externally toothed gear 15 includes a cylindrical body portion 15a, an annular diaphragm 15b extending radially inward from one end of the cylindrical body portion 15a, and an annular convex portion 15c. The inner circumference of the diaphragm 15b is continuous and extends inward. The other end portion of the cylindrical body portion 15a is formed as an open end, and the outer peripheral surface portion of the open end is formed with external teeth 15d.

The flexible externally toothed gear 15 is in a state in which the opening end side on which the external teeth 15d are formed is disposed on the input side (motor assembly side). The outer teeth 15d are positioned opposite the inner teeth 14a of the rigid internally toothed gear 14 and are engageable with the inner teeth 14a.

The harmonic generator 16 is provided with an input shaft 6, a rigid cam plate 16a attached to the outer peripheral surface of the input shaft 6, and a wave bearing 16b attached to the outer peripheral surface of the rigid cam plate 16a. The rigid cam plate 16a is mounted on the input shaft 6 by a aligning device composed of an OLDHAM coupler 16c. The wave bearing 16b is provided with a ball bearing having an outer wheel and an inner wheel that are deflectable in a radial direction. The rigid cam plate 16a of the present embodiment has an elliptical contour, and the wave bearing 16b is attached to the rigid cam plate 16a and the outer tooth forming portion of the cylindrical body portion 15a of the flexible externally toothed gear 15. Between the inner circumferences. Therefore, the external tooth forming portion of the flexible externally toothed gear 15 is bent into an elliptical shape, and the portion of the external tooth 15d which is located at both ends of the elliptical shape in the long axis direction is the internal tooth 14a of the rigid internally toothed gear 14. Partially bite.

The flexible externally toothed gear 15 is fixed to be coaxial with the output disk 4. In other words, the annular end surface on the output side of the annular convex surface portion 15c of the flexible externally toothed gear 15 is fixed to the inner end surface of the output disk 4. The fixing device for fixing the annular convex portion 15c to the output disk 4 is provided with an annular bearing housing 21 which is coaxial with the annular end surface located inside the annular convex portion 15c. And a plurality of fastening bolts 22, which are clamped and fixed to the output disk 4 by the annular shape of the annular convex portion 15c. A second input bearing 8 for supporting the shaft end portion of the input shaft 6 is attached to the inner peripheral surface of the bearing housing 21.

As described above, the input shaft 6 of the harmonic generator 16 is supported by the first input bearing 7 and the second input bearing 8. Therefore, the harmonic generator 16 is fixed at a position in the axial direction. When the motor is assembled, it is not necessary to substantially perform the work of positioning the harmonic generator 16 in the axial direction. Therefore, the motor assembly work is very easy.

Further, the annular convex surface portion 15c of the flexible externally toothed gear 15 is sandwiched between the output disk 4 and the bearing housing 21. The three members 15c, 4, and 21 are locked and fixed by the fastening bolts 22 in this state. It is not necessary to perform a thread cutting process on the annular convex surface portion 15c of the flexible externally toothed gear 15, or a concave portion for a bearing, and the like, and it is possible to suppress an increase in the number of processing steps of the flexible externally toothed gear. Further, since the three members are locked together by the fastening bolts 22, the three-member fixing device can be configured with a small number of components. Therefore, a harmonic gear unit that supports the input shaft 6 by a bearing device that is easy to manufacture and assemble can be obtained.

Here, the output disk 4 is formed with a center through hole 4a. The inner diameter of the center through hole 4a is formed in an annular shape formed on the flexible externally toothed gear 15 The inner diameter of the center through hole 15e of the convex portion 15c is the same. The bearing housing 21 is formed with a press-in cylinder 21a. The press-in cylinder 21a protrudes from the inner peripheral edge portion of the annular end surface on the output side of the bearing housing 21 in a coaxial state toward the output side. The press-fitting cylinder 21a is press-fitted into the center through hole 15e fixed to the annular convex surface portion 15c and the center through hole 4a of the output disk 4. By pressing the cylinder 21a, the three members 15, 21, 4 can be locked and fixed so as not to form an eccentric core.

Next, the input shaft 6 includes a hollow shaft portion 6b including a shaft attachment hole 6a for connecting the motor shaft, and a solid shaft portion 6c having a smaller diameter than the hollow shaft portion 6b. The solid shaft portion 6c protrudes coaxially from the end of the lock shaft of the bearing housing 21 side of the hollow shaft portion 6b. The shaft end portion of the solid shaft portion 6c extends coaxially toward the inside of the bearing housing 21. The second input bearing 8 attached to the inside of the bearing housing 21 supports the shaft end portion of the solid shaft portion 6c of the input shaft 6.

A rigid cam plate 16a is attached to the hollow shaft portion 6b of the input shaft 6. The hollow shaft portion 6b is provided with a shaft end portion that penetrates the center through hole 3a of the end plate 3 and protrudes toward the input side. The end of the shaft end is open and formed as a motor shaft mounting hole. The motor shaft 10a is inserted into the motor shaft mounting hole in the axial direction, and is coupled and fixed to the hollow shaft portion 6b coaxially. The first input bearing 7 is attached to the inner peripheral surface of the center through hole 3a of the end plate 3. The first input bearing 7 supports the hollow shaft portion 6b of the input shaft 6. Further, an oil seal 23 is attached to the outside of the first input bearing 7.

1‧‧‧Harmonic Gear Unit

2‧‧‧Cylindrical shell

2a‧‧‧ input side open end

2b‧‧‧ output side open end

3‧‧‧End board

3a‧‧‧Center through hole

3b‧‧‧Outside end face

4‧‧‧Output disc

4a‧‧‧Center through hole

5‧‧‧Harmonic gear unit

6‧‧‧ Input shaft

6a‧‧‧Axis mounting holes

6b‧‧‧ hollow shaft

6c‧‧‧solid shaft

7‧‧‧1st input bearing

8‧‧‧2nd input bearing

9‧‧‧Assembled flange

10‧‧‧ motor

10a‧‧‧Motor shaft

A‧‧‧Rotary actuator

11‧‧‧ fastening bolts

12‧‧‧ Crossed Roller Bearings

12a‧‧‧Outside

12b‧‧‧Roller

12c‧‧‧Inner wheel side track surface

13‧‧‧ fastening bolts

14‧‧‧Rigid internal gear

14a‧‧‧ internal teeth

15‧‧‧Flexible external gear

15a‧‧‧Cylindrical body

15b‧‧‧Separator

15c‧‧‧Ringed convex face

15d‧‧‧ external teeth

15e‧‧‧Center through hole

16‧‧‧Harmonic Generator

16a‧‧‧Rigid cam plate

16b‧‧‧ Wave bearing

16c‧‧‧OLDHAM coupling

21‧‧‧ bearing housing

21a‧‧‧ pressed into the cylinder

22‧‧‧ fastening bolts

23‧‧‧ oil seal

Fig. 1 is a longitudinal sectional view showing a harmonic gear unit according to an embodiment of the present invention, and an end surface view on the output side.

1‧‧‧Harmonic Gear Unit

2‧‧‧Cylindrical shell

2a‧‧‧ input side open end

2b‧‧‧ output side open end

3‧‧‧End board

3a‧‧‧Center through hole

3b‧‧‧Outside end face

4‧‧‧Output disc

4a‧‧‧Center through hole

5‧‧‧Harmonic gear unit

6‧‧‧ Input shaft

6a‧‧‧Axis mounting holes

6b‧‧‧ hollow shaft

6c‧‧‧solid shaft

7‧‧‧1st input bearing

8‧‧‧2nd input bearing

9‧‧‧Assembled flange

10‧‧‧ motor

10a‧‧‧Motor shaft

A‧‧‧Rotary actuator

11‧‧‧ fastening bolts

12‧‧‧ Crossed Roller Bearings

12a‧‧‧Outside

12b‧‧‧Roller

12c‧‧‧Inner wheel side track surface

13‧‧‧ fastening bolts

14‧‧‧Rigid internal gear

14a‧‧‧ internal teeth

15‧‧‧Flexible external gear

15a‧‧‧Cylindrical body

15b‧‧‧Separator

15c‧‧‧Ringed convex face

15d‧‧‧ external teeth

15e‧‧‧Center through hole

16‧‧‧Harmonic Generator

16a‧‧‧Rigid cam plate

16b‧‧‧ Wave bearing

16c‧‧‧OLDHAM coupling

21‧‧‧ bearing housing

21a‧‧‧ pressed into the cylinder

22‧‧‧ fastening bolts

23‧‧‧ oil seal

Claims (2)

A harmonic gear unit (1) having an input bearing, characterized by: a cylindrical casing (2); an end plate (3) fixed to an input side open end (2a) of the cylindrical casing (2) : The output disc (4) is rotatably mounted on the output side open end (2b) of the cylindrical casing (2); the cup type harmonic gear device (5) is incorporated in the aforementioned cylinder An inner side of the casing (2); an input shaft (6) extending through a central through hole (3a) formed in the end plate (3); and a fixing device for cupping the harmonic gear device (5) a flexible external gear (15), locked and fixed to the output disc (4); and a first input bearing (7) and a second input bearing (8) for supporting the input shaft (6); The flexible externally toothed gear (15) of the harmonic gear device (5) is provided so as to be superposed on the inner end surface of the end plate (3) side of the output disk (4). a ring-shaped convex surface portion (15c), wherein the harmonic generator (16) of the harmonic gear device (5) includes the input shaft (6) and the hollow shaft portion attached to the input shaft (6) ( 6b) the outer peripheral rigid cam plate (16a), and mounted on This rigidity a wave bearing (16b) on the outer peripheral surface of the cam plate (16a), wherein the fixing device includes a bearing housing (21) and an annular shape facing the end plate (3) side of the annular convex surface portion (15c) The end surface is superposed on the coaxial annular shape; and a plurality of fastening bolts (22) are mounted on the annular convex portion (15c) by the bearing housing (21), and are locked and fixed to the output disc (4) The input shaft (6) includes a hollow shaft portion (6b) including a shaft mounting hole (6a) for coupling the motor shaft, and a solid shaft portion (6c) from the hollow shaft portion (6b) The blocking shaft end portion on the side of the bearing housing (21) protrudes coaxially and extends into the bearing housing (21), and the first input bearing (7) is mounted on the center through hole of the end plate (3). Between the inner circumferential surface of (3a) and the outer circumferential surface of the hollow shaft portion (6b), the second input bearing (8) is attached to the inner circumferential surface of the bearing housing (21) and the solid shaft portion (6c) ) between the outer perimeters. The harmonic gear unit (1) having an input bearing according to the first aspect of the invention, wherein the output disc (4) is provided with a central through hole (4a) having an inner diameter and the circle The center through hole (15e) of the annular convex surface portion (15c) is the same, and the bearing housing (21) is provided with a press-in cylinder (21a) that is press-fitted and fixed to the annular convex surface portion (15c). The center through hole (15e) and the center of the output disk (4) Through hole (4a).