JP2014074450A - Wave gear unit with input bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wave gear unit with an input bearing that has an input shaft supported by an easy-to-manufacture and -assemble bearing mechanism.SOLUTION: In a wave gear unit 1, an input shaft 6 of a built-in wave gear mechanism 5 is supported by a first input bearing 7 and a second input bearing 8. Axial positions of the input shaft 6 and a wave generator 16 mounted to it are fixed, and therefore, a motor assembling operation is simple. A bearing housing 21 of the second input bearing 8 supporting the input shaft 6 holds an annular boss 15c of a flexible external tooth gear 15, and is fastened and fixed to an outputting disc 4 by a fastening bolt 22. A stationary mechanism for fixing the bearing mechanism of the input shaft 6 and the flexible external tooth gear 15 to the outputting disc 4 is formed by a simple constitution without applying screw cutting processing, recess processing and the like to the annular boss 15c.

Description

  The present invention relates to a wave gear unit with an input bearing capable of easily assembling a motor.

  As a wave gear unit with an input bearing, a unit-type wave gear device including a cup-shaped flexible external gear disclosed in Patent Document 1 is known. In this unit type wave gear device, an input shaft is formed on one end face of the rigid cam plate of the wave generator, and a shaft portion is formed on the other end face of the rigid cam plate. The input shaft is supported by a first bearing attached to the unit case end plate, and the tip of the opposite shaft portion is supported by a first input bearing attached to a disk-shaped boss of the flexible external gear. .

  The wave generator is fixed in the axial direction by the pair of input bearings, and the rigid internal gear and the wave generator are positioned in the axial direction. Therefore, when the unit type wave gear device is connected to the motor shaft of the motor to constitute the actuator, it is only necessary to connect and fix the motor shaft to the input shaft, and the assembling work is simple.

  In the unit type wave gear device, a concave portion for mounting a bearing is formed on one end surface of a disk-shaped boss of a cup-shaped flexible external gear, and an output shaft is formed integrally on the other end surface. By simplifying the structure and reducing the number of parts, assembly work can be easily performed.

  Patent Document 2 discloses an actuator having a configuration in which a wave gear device and a motor are integrated. In the wave gear device incorporated in this actuator, an annular boss of a cup-shaped flexible external gear is screwed into and fixed to the center through hole of the end plate of the housing from one direction along the device axis, An annular bearing is press-fitted and fixed to the boss from the same direction along the device axis, and the 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 mounted on the bearing bearing, and a portion in the axial direction of the hollow shaft is supported by a bearing attached to a partition wall that partitions the wave gear device and the motor.

JP 2002-21948 A JP 2002-243000 A

  Here, in the unit type wave gear device disclosed in Patent Document 1, a concave portion for mounting a bearing or the like is formed on a boss of a flexible external gear manufactured by cutting. For this reason, the processing man-hour of a flexible external gear increases. In the actuator disclosed in Patent Document 2, an annular boss of a cup-shaped flexible external gear is screwed into a central through hole of the end plate of the housing from the direction along the device axis, and is fixed to the boss. An annular bearing is press-fitted and fixed from the same direction. For this reason, the bearing portion becomes longer in the axial direction, which is disadvantageous for shortening the apparatus in the axial direction. Moreover, since it is necessary to process the boss | hub provided with the screw part screwed and fixed to an end plate, the process man-hour of a flexible external gear also increases.

  An object of the present invention is to propose a wave gear unit with an input bearing in which an input shaft is supported by a bearing mechanism that is easy to manufacture and assemble.

In order to solve the above problems, the wave gear unit with an input bearing of the present invention is:
A cylindrical casing;
An end plate fixed to the input side opening end of the cylindrical casing;
An output disk attached in a rotatable state to the output side opening end of the cylindrical casing;
A cup-shaped wave gear mechanism incorporated inside the cylindrical casing;
An input shaft extending through a central through hole formed in the end plate;
A fixing mechanism for fastening and fixing the cup-shaped flexible external gear of the wave gear mechanism to the output disk;
A first input bearing and a second input bearing for supporting the input shaft;
The flexible external gear includes an annular boss coaxially stacked on an inner end surface facing the end plate in the output disc,
The fixing mechanism includes an annular bearing housing that is coaxially overlapped on an annular end surface facing the end plate of the annular boss, and the bearing housing is fastened to the output disk with the annular boss interposed therebetween. A plurality of fastening bolts to be fixed,
The input shaft includes a hollow shaft portion having a shaft mounting hole for connecting a motor shaft, and a solid shaft that projects coaxially from the end of the sealed shaft on the bearing housing side of the hollow shaft portion and extends to the inside of the bearing housing. A shaft portion,
The wave generator of the wave gear mechanism includes the input shaft, a rigid cam plate attached to the outer periphery of the hollow shaft portion of the input shaft, and a wave bearing attached to the outer peripheral surface of the rigid cam plate,
The first input bearing is mounted between an inner peripheral surface of the central through hole of the end plate and an outer peripheral surface of the hollow shaft portion,
The second input bearing is mounted between an inner peripheral surface of the bearing housing and an outer peripheral surface of the solid shaft portion.

  The input shaft of the wave generator is supported by the first input bearing and the second input bearing at the input side portion and the output side portion, respectively. Therefore, the wave generator is fixed in the axial direction by the first and second input bearings, and the axial positioning of these members is substantially unnecessary when the motor is assembled.

  The annular boss of the flexible external gear is sandwiched between the output side end plate and the bearing housing. These three members are fastened and fixed by fastening bolts in this state. An annular boss does not require threading or recess processing for a bearing. Therefore, an increase in the number of processing steps for the flexible external gear can be suppressed. Moreover, since the three members are fastened together with fastening bolts, the fixing mechanism for these three members can be configured with a small number of parts. Therefore, a wave gear unit with an input bearing in which the input shaft 6 is supported by a bearing mechanism that is easy to manufacture and assemble is obtained.

  Here, in order to assemble the three members with high accuracy, the following may be performed. The central through hole of the annular boss of the flexible external gear and the central through hole formed in the output disk are defined as through holes having the same inner diameter. Further, a press-fit cylinder that is press-fitted and fixed in the center through hole of the annular boss and the center through hole of the output disk is formed integrally with the bearing housing. In this way, the three members can be fastened and fixed without misalignment by the press-fitting cylinder.

It is the longitudinal cross-sectional view which shows the wave gear unit which concerns on embodiment of this invention, and the end elevation on the output side.

  A wave gear unit according to an embodiment of the present invention will be described below with reference to the drawings. Fig.1 (a) is a longitudinal cross-sectional view which shows the state which assembled | attached the motor to the wave gear unit which concerns on this Embodiment. FIG. 1B is an end view of the output side.

  The wave gear unit 1 is rotatable in a cylindrical casing 2, an end plate 3 fixed to the input side opening end 2 a of the cylindrical casing 2, and an output side opening end 2 b on the opposite side of the cylindrical casing 2. An attached output disk 4 is provided.

  A cup-shaped wave gear mechanism 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 passes through the center through hole 3a in a coaxial state.

  The input shaft 6 is rotatably supported by a first input bearing 7 mounted on the inner peripheral surface of the central through hole 3a of the end plate 3. The input shaft 6 is supported in a rotatable state by a second input bearing 8 inside the wave gear mechanism 5. A motor 10 is coaxially assembled to the outer end surface 3 b of the end plate 3 via an annular mounting flange 9, and the motor shaft 10 a is connected and fixed coaxially to the input shaft 6. The motor 10 and the wave gear unit 1 constitute a rotary actuator A.

  When the motor 10 is driven to rotate, the motor rotation is decelerated by the wave gear mechanism 5 and the decelerated rotation is taken out from the output disk 4. A load side member (not shown) connected and fixed to the output disk 4 is rotationally driven.

  The configuration of each part of the wave gear unit 1 will be described in detail. The cylindrical casing 2 has a large-diameter flange portion at the input-side opening end 2 a, and the outer peripheral portion of the disc-shaped end plate 3 is fixed to the annular end surface by fastening bolts 11. Has been. An output disk 4 is attached to the output side opening end 2b of the cylindrical casing 2 via a cross roller bearing 12 in a rotatable state. The outer ring 12 a of the cross roller bearing 12 is fixed to the annular end surface of the output side opening end 2 b of the cylindrical casing 2 by fastening bolts 13. An outer peripheral edge portion of the output disk 4 that is coaxially disposed inside the outer ring 12 a functions as an inner ring of the cross roller bearing 12. That is, a raceway surface 12c on the inner ring side of the roller 12b is formed on the circular outer peripheral surface of the output disk 4.

  The wave gear mechanism 5 includes an annular rigid internal gear 14, a cup-shaped flexible external gear 15, and a wave generator 16. The rigid internal gear 14 is fixed to the inner peripheral surface portion of the input side opening end 2 a of the cylindrical casing 2. The flexible external gear 15 is continuous with a cylindrical body 15a, an annular diaphragm 15b extending radially inward from one end of the cylindrical body 15a, and an inner peripheral edge of the diaphragm 15b. An annular boss 15c extending inward is provided. The other end of the cylindrical body portion 15a is an open end, and external teeth 15d are formed on the outer peripheral surface portion of the open end.

  The flexible external gear 15 is arranged in a state where the open end side where the external teeth 15d are formed faces the input side (motor assembly side). The external teeth 15d are in positions facing the internal teeth 14a of the rigid internal gear 14, and can mesh with the internal teeth 14a.

  The wave generator 16 includes 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 attached to the input shaft 6 via an alignment mechanism comprising an Oldham coupling 16c. The wave bearing 16b is a ball bearing having an outer ring and an inner ring that can be bent in the radial direction. The rigid cam plate 16a of this example has an elliptical outline, and the wave bearing 16b includes a rigid cam plate 16a and an inner peripheral surface of an outer tooth forming portion of the cylindrical body portion 15a of the flexible external gear 15. It is installed between. Therefore, the external tooth forming portion of the flexible external gear 15 is bent in an elliptical shape, and the external tooth portions located at both ends in the major axis direction of the elliptical shape are the internal teeth of the rigid internal gear 14. It meshes with teeth.

  The flexible external gear 15 is coaxially fixed to the output disk 4. That is, the annular end surface on the output side of the annular boss 15 c of the flexible external gear 15 is fixed to the inner end surface of the output disk 4. The fixing mechanism for fixing the annular boss 15c to the output disc 4 includes an annular bearing housing 21 coaxially stacked on the inner annular end face of the annular boss 15c, and the bearing housing 21 is connected to the annular boss 15c. A plurality of fastening bolts 22 that are fastened and fixed to the output disk 4 with 15c interposed therebetween are provided. A second input bearing 8 that supports the shaft end of the input shaft 6 is mounted on the inner peripheral surface of the bearing housing 21.

  As described above, the annular boss 15 c of the flexible external gear 15 is sandwiched between the output disk 4 and the bearing housing 21. Further, these three members are fastened and fixed by fastening bolts 22 in this state. The annular boss 15c of the flexible external gear 15 does not require a threading process, a recess process for a bearing, or the like, and can suppress an increase in the number of processing steps for the flexible external gear. Further, since the three members are fastened together with the fastening bolts 22, the fixing mechanism for these three members can be configured with a small number of parts. Therefore, a wave gear unit in which the input shaft 6 is supported by a bearing mechanism that is easy to manufacture and assemble is obtained.

  Here, the output disk 4 is formed with a central through hole 4a having the same inner diameter as the central through hole 15e of the annular boss 15c of the flexible external gear 15. A press-fit cylinder 21 a is formed in the bearing housing 21. The press-fit cylinder 21 a protrudes coaxially from the inner peripheral edge portion of the annular end surface on the output side of the bearing housing 21 to the output side. The press-fit cylinder 21a is press-fitted and fixed in the center through hole 15e of the annular boss 15c and the center through hole 4a of the output disk 4. The three members 15, 21, 4 can be fastened and fixed by the press-fitting cylinder 21 a without misalignment.

  Next, the input shaft 6 includes a hollow shaft portion 6b having a shaft mounting hole 6a for connecting a motor shaft, and a solid shaft portion 6c having a smaller diameter than the hollow shaft portion 6b. The solid shaft portion 6c projects coaxially from the end of the sealing shaft on the bearing housing 21 side in the hollow shaft portion 6b. The shaft end portion of the solid shaft portion 6 c extends coaxially inside the bearing housing 21. The second input bearing 8 mounted inside the bearing housing 21 supports the shaft end portion of the solid shaft portion 6 c of the input shaft 6.

  A wave generator 16 is attached to the hollow shaft portion 6 b of the input shaft 6. The hollow shaft portion 6b includes a shaft end portion that passes through the central through hole 3a of the end plate 3 and protrudes toward the input side. The end of the shaft end is open and serves as a motor shaft mounting hole. The motor shaft 10a is inserted in the axial direction from the motor shaft mounting hole, and is coaxially connected and fixed to the hollow shaft portion 6b. A first input bearing 7 is mounted on the inner peripheral surface of the center through hole 3 a of the end plate 3 and supports the hollow shaft portion 6 b of the input shaft 6. An oil seal 23 is attached to the outside of the first input bearing 7.

  Thus, the input shaft 6 on which the wave generator 16 is mounted is supported by the first input bearing 7 and the second input bearing 8. Therefore, the position of the wave generator 16 in the axial direction is fixed. When the motor is assembled, positioning of the wave generator 16 in the axial direction is substantially unnecessary. Therefore, the motor assembling work is easy.

DESCRIPTION OF SYMBOLS 1 Wave gear unit 2 Cylindrical casing 2a Input side opening end 2b Output side opening end 3 End plate 3a Center through-hole 3b Outer end surface 4 Output disk 4a Center through-hole 5 Wave gear mechanism 6 Input shaft 6a Shaft mounting hole 6b Hollow shaft Part 6c Solid shaft part 7 First input bearing 8 Second input bearing 9 Mounting flange 10 Motor 10a Motor shaft A Rotating actuator 11 Fastening bolt 12 Cross roller bearing 12a Outer ring 12b Roller 12c Inner ring side raceway surface 13 Fastening bolt 14 Rigidity Internal gear 14a Internal gear 15 Flexible external gear 15a Cylindrical body 15b Diaphragm 15c Annular boss 15d Outer gear 15e Center through hole 16 Wave generator 16a Rigid cam plate 16b Wave bearing 16c Oldham coupling 21 Bearing housing 21a Press-fit cylinder 22 Fastening bolt 23 Oil seal

Claims (2)

A cylindrical casing (2);
An end plate (3) fixed to the input side open end (2a) of the cylindrical casing (2);
An output disc (4) attached to the output side open end (2b) of the cylindrical casing (2) in a rotatable state;
A cup-shaped wave gear mechanism (5) incorporated inside the cylindrical casing (2);
An input shaft (6) extending through a central through hole (3a) formed in the end plate (3);
A fixing mechanism for fastening and fixing the cup-shaped flexible external gear (15) of the wave gear mechanism (5) to the output disk (4);
A first input bearing (7) and a second input bearing (8) for supporting the input shaft (6);
The flexible external gear (15) includes an annular boss (15c) coaxially stacked on an inner end surface facing the end plate (3) side of the output disc (4),
The fixing mechanism includes an annular bearing housing (21) coaxially stacked on an annular end surface facing the end plate (3) side of the annular boss (15c), and the bearing housing (21). A plurality of fastening bolts (22) sandwiching and fixing the annular boss (15c) to the output disk (4);
The input shaft (6) includes a hollow shaft portion (6b) having a shaft mounting hole (6a) for connecting a motor shaft, and a sealed shaft end on the bearing housing (21) side of the hollow shaft portion (6b). A solid shaft portion (6c) protruding coaxially from the portion and extending to the inside of the bearing housing (21),
The wave generator (16) of the wave gear mechanism (5) includes a rigid cam plate (16a) mounted on the outer periphery of the input shaft (6) and the hollow shaft portion (6b) of the input shaft (6). And a wave bearing (16b) mounted on the outer peripheral surface of the rigid cam plate (16a),
The first input bearing (7) is mounted between an inner peripheral surface of the central through hole (3a) of the end plate (3) and an outer peripheral surface of the hollow shaft portion (6b),
The second input bearing (8) is mounted between the inner peripheral surface of the bearing housing (21) and the outer peripheral surface of the solid shaft portion (6c). Unit (1). In claim 1,
The output disk (4) includes a central through hole (4a) having the same inner diameter as the central through hole (15e) of the annular boss (15c),
The bearing housing (21) includes a press-fit cylinder (21a) that is press-fitted and fixed to the center through hole (15e) of the annular boss (15c) and the center through hole (4a) of the output disk (4). A wave gear unit (1) with an input bearing.

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