WO2014069709A1

WO2014069709A1 - Flexspline having toothed gear coupled to elastic bodies and fins, and harmonic drive having same

Info

Publication number: WO2014069709A1
Application number: PCT/KR2012/010348
Authority: WO
Inventors: 이윤규
Original assignee: Lee Yun Gyu
Priority date: 2012-10-31
Filing date: 2012-11-30
Publication date: 2014-05-08
Also published as: KR101280291B1

Abstract

The present invention relates to a harmonic drive and provides: first and second elastic bodies which are formed into a circular ring structure; and a flexspline which includes a plurality of fins in the shape of teeth such that one side portion thereof is coupled to the first elastic body and the other side portion is coupled to the second elastic body in order to symmetrically connect the first and second elastic bodies to each other. Therefore, the flexspline can be prevented from damage caused by excessive torques and repetitive distortion stress.

Description

Flexpline with tooth coupled to elastic body and pin and harmonic drive with same

The present invention relates to a speed reducer, and in particular, industrial robot, humanoid robot, semiconductor (wafer) manufacturing device, electronic component insertion device, ceramic forming device, optical disk manufacturing device, medical device, NC (Numerical Control) lathe, etc. It relates to a flexplane of a reducer used in machinery that requires.

In general, reducers (also called harmonic drives) (hereinafter referred to as harmonic drives) are industrial robots, humanoid robots, semiconductor (wafer) manufacturing devices, electronic component insertion devices, ceramic forming devices, optical disc manufacturing devices, medical devices, and NC (Numerical Control). As a gear reducer widely used in various devices such as lathes, it is small in size, light weight, low in noise during gear rotation, high precision reduction ratio can be obtained, and power transmission efficiency is excellent.

Harmonic drives basically include a wave generator, flexspline and circular spline. In the wave generator, a ball bearing is assembled to an outer circumferential surface of an elliptic cam to which an input shaft is connected, and a flexpline is fitted to the ball bearing outer ring. The flexpline is a circular thin metal elastic body having a first tooth (gear teeth) formed on one outer circumferential surface, and a second spline formed on the inner circumferential surface of the circular spline corresponding to the first tooth of the flexpline.

The harmonic drive transmits power in the order of the input shaft, the wave generator connected to the input shaft, the flexplane, the circular spline meshed with the flexplane, and the output shaft connected to the circular spline. That is, when the wave generator coupled with the input shaft rotates in the clockwise direction, the flexpline gradually generates elastic deformation and some of the first teeth of the flexpline are coupled with some of the second teeth of the circular spline to transmit power. . In this case, a speed reducer having a large reduction ratio may be implemented due to a difference between the dimension of the first tooth formed on the outer circumferential surface of the flexpline and the dimension of the second tooth of the circular spline.

However, in the harmonic drive according to the prior art, in order to elastically deform the flexpline through the wave generated from the wave generator, the flexpline needs to be manufactured with a relatively thin metal elastic body, which requires a relatively expensive manufacturing equipment, which is enormous for initial equipment construction. Cost is required, resulting in an increase in product cost, which lowers the economic feasibility. Furthermore, if excessive torque is applied to the flexplane repeatedly while the wave generator is fixed, plastic deformation occurs in the flexplane formed of a thin metal elastic body, thereby causing a problem such that the first tooth of the flexplane is damaged.

Accordingly, the present invention has been proposed to solve the problems of the prior art, and provides a flexplane and a harmonic drive having the same, which can be prevented from being easily broken by excessive torque and repeated torsional stress while lowering the manufacturing cost. Its purpose is to.

JP 1993-332403 A, December 14, 1993

US 2008-0110287 A1, 2008. 05. 15.

US 2007-0101820 A1, 2007. 05. 10.

US 2010-0319484 A1, December 23, 2010.

US 2010-0288066 A1, November 18, 2010.

According to an aspect of the present invention, there is provided a first and second elastic body having a circular ring structure, and one side of the first elastic body in order to connect the first and second elastic bodies to each other in a symmetrical structure. And a plurality of pins fastened to the second elastic member and coupled to the second elastic member to form a tooth.

Preferably, the first and second elastic bodies may each be made of a thermoplastic elastomer.

In addition, the present invention according to another aspect for achieving the above object is to connect the wave generator, the first and second elastic body made of a circular ring structure, and the first and second elastic body in a mutually symmetric structure One side is coupled to the first elastic body and the other side includes a plurality of pins are fastened to the second elastic body to form a first tooth, the way part generator is inserted into the inner peripheral surface and fastened to the wave generated in the wave generator And a body having a flexpline having a shape deformation of the first and second elastic bodies and a circular ring structure having a second tooth formed on an inner circumferential surface into which the flexpline is inserted. And a circular spline that partially engages the pin forming the first tooth of the flexpline by shape deformation of the first and second elastic bodies. It provides a harmonic drive.

Preferably, the wave generator is coupled to the input shaft, the elliptical cam member is rotated in conjunction with the input shaft to generate the wave, the inner ring in contact with the outer peripheral surface of the cam member, and the inner peripheral surface of the flexplane It may include a bearing including an outer ring, and a movable body provided between the inner ring and the outer ring to press the outer ring in accordance with the rotation of the cam member.

Preferably, the dimension of the second tooth may be 2n (n is a natural number) more than the number of the pins.

As described above, according to the present invention, the first and second elastic body, and the flexplane including a plurality of pins that interconnect the first and second elastic body to partially engage the teeth of the circular supply; By providing a harmonic drive having the same, it is possible to prevent the flexpline from being damaged by excessive torque and repeated torsional stress while significantly lowering the manufacturing cost as compared with the conventional thin metal elastomer.

1 is an exploded perspective view showing a harmonic drive according to an embodiment of the present invention.

FIG. 2 is an assembled cross sectional view showing a cross section in an assembled state of the harmonic drive shown in FIG.

3 is a perspective view showing a cross section in an assembled state of the harmonic drive shown in FIG.

4 is a side perspective view of a wave generator according to the present invention;

FIG. 5 is a front view of the wave generator shown in FIG. 4 as viewed from the front; FIG.

6 is an assembled perspective view showing the flexpline according to the present invention.

FIG. 7 is an exploded perspective view showing the flexpline shown in FIG. 6. FIG.

8 is a perspective view of a circular spline according to the present invention;

FIG. 9 is a front view of the circular spline shown in FIG. 8. FIG.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms.

In this specification, the embodiments are provided so that the disclosure of the present invention may be completed and the scope of the present invention may be completely provided to those skilled in the art. And the present invention is only defined by the scope of the claims. Thus, in some embodiments, well known components, well known operations and well known techniques are not described in detail in order to avoid obscuring the present invention.

Also, like reference numerals refer to like elements throughout. In addition, the terms used (discussed) herein are for the purpose of describing particular embodiments only and are not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. In addition, components and operations referred to as 'includes (or includes)' do not exclude the presence or addition of one or more other components and operations.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. Also, the terms defined in the commonly used dictionaries are not ideally or excessively interpreted unless they are defined.

Hereinafter, technical features of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view showing a harmonic drive according to an embodiment of the present invention, Figure 2 is an assembled cross-sectional view showing a cross section of the assembled state of the harmonic drive shown in Figure 1, Figure 3 is A perspective view showing a cross section of the harmonic drive shown in FIG.

1 to 3, a harmonic drive according to an embodiment of the present invention includes a wave generator 10 for generating waves and a flexpline whose shape is deformed by waves generated by the wave generator 10. 20 and the circular spline 30 which decelerates and rotates by interaction with the flexpline 20. The wave generator 10 may further include a house 40 in which the wave generator 10, the flexpline 20, and the circular spline 30 are accommodated.

4 is a side perspective view illustrating the wave generator according to the present invention, and FIG. 5 is a front view of the wave generator shown in FIG.

4 and 5, the wave generator 10 according to the present invention includes a cam member 11, a cam member 11, and a flexpline 20, in which an input shaft (not shown) is coupled to generate a wave. Interposed between the) includes a bearing 12 to facilitate the relative rotation.

The cam member 11 includes an insertion hole 11a into which the input shaft is inserted. For example, the input shaft may be a driving shaft before deceleration as an output shaft of the driving motor. The cam member 11 may be formed in an elliptical shape having a long axis and a short axis. The flexpline 20 of the portion corresponding to the long axis of the cam member 11 is engaged with the circular spline 30, and the flexpline 20 of the portion corresponding to the short axis is spaced apart from the circular spline 30. do.

The bearing 12 is deformed in accordance with the shape of the cam member 11 when coupled to the outside of the cam member 11, in conjunction with the shape deformation of the cam member 11, the flexpline 20 also cam member 11 The shape is deformed in correspondence with the deformed shape. Here, the bearing 12 may be made of engineering plastic, thereby making it easy to deform the shape according to the wave generated by the cam member 11 as compared to the bearing made of a conventional metal material. The bearing 12 includes a plurality of movable bodies 12b and an inner ring 12a and an outer ring 12c that support the movable body 12b in a rolling motion. Here, the movable body 12b may be either a ball or a needle.

In addition, the wave generator 10 according to the present invention may further include a bearing 13 and a snap ring 14 interposed between the inner ring 12a and the cam member 11 of the bearing 12. The bearing 13 buffers the radial load and thrust load transmitted from the input shaft to the cam member 11 to block the transmission to the bearing 12 of the wave generator 10 coupled with the flexplane 20. The snap ring 14 prevents the cap member 11 from interfering with the house 40.

6 is an assembled perspective view for explaining the flexplane according to the present invention, Figure 7 is an exploded perspective view.

6 and 7, the flexpline 20 according to the present invention is coupled to the cam member 11 with the bearing 12 of the wave generator 10 interposed therebetween. Through this, the flexpline 20 is deformed by the wave generated by the cam member 11.

The flexpline 20 includes a first elastic body 21 having a circular ring structure, a second elastic body 22 having a circular ring structure similar to the first elastic body 21, and first and second elastic bodies. A plurality of pins 23 having one side fastened to the first elastic body 21 and the other side fastened to the second elastic body 22 to form a tooth (hereinafter, referred to as a first tooth) to connect the 21 and 22 to each other. ).

Coupling grooves (not shown) in which one side of the plurality of pins 23 is inserted into one side of the first elastic body 21 to face the second elastic body 22 to be stably coupled to the plurality of pins 23, for example. (Hereinafter, referred to as a first coupling groove), and correspondingly, the coupling groove into which the second elastic member 22 and the other side of the pin 23 is inserted into one side facing the first elastic body 21 ( (Not shown) (hereinafter referred to as a second coupling groove) may be provided. As a result, the plurality of pins 23 connect the first and second

elastic bodies

21 and 22 to each other so that the first and second

elastic bodies

21 and 22 are symmetrical with each other so that the first and second

elastic bodies

21 and 22 are connected to each other. The first tooth is formed therebetween.

The pin 23 forming the first tooth is partially engaged with the tooth of the circular spline 30 (hereinafter referred to as the second tooth). The number of such pins 23 differs from the dimensions of the second tooth of the circular spline 30. For example, the number of the pins 23 is 2n (n is a natural number) smaller than the dimension of the second tooth of the circular spline 30. In other words, the dimension of the second tooth of the circular spline 30 may be formed by 2n more than the number of the pins 23.

The first and second

elastic bodies

21 and 22 have a simple manufacturing process and can be manufactured through a molding process, for example, a thermoplastic elastomer, in order to stably shape the shape due to the waveform of the wave generator 10. It is preferable to form. For example, thermoplastic elastomers include SBC (styrene), Styrenic Block Copolymer (styrene), TPO (Thermoplastic Olefinic Elastomer), an olefin, TPU (Thermoplastic Polyurethane), and amide (urethane). amide) TPAE (Thermoplastic Polyamide), polyester-based (TPEE) polyester-based Thermoplastic Engineering Elastomer (TPEE) can be used. In addition, TPV (Thermoplastic Vulcanizates), TPR (Thermoplastic Rubber) and the like can be used.

8 is a perspective view illustrating a circular spline according to the present invention, and FIG. 9 is a front view.

8 and 9, the circular spline 30 according to the present invention includes a body 31 having a circular ring structure in which the flexpline 20 is inserted into an inner circumferential surface thereof. On the inner circumferential surface of the body 31 is formed a second tooth 32 which partially engages with the plurality of pins 23 of the flexpline 20.

The size of the second teeth 32 formed on the inner circumference of the body 31 of the circular spline 30 is formed by 2n more than the number of the pins 23, through which the deceleration rotation can be implemented. For example, when the number of the pins 23 forming the first tooth of the flexpline 20 is 100 and the dimensions of the second tooth of the circular spline 30 are 102, the reduction ratio is 100: 2 (50). It becomes: 1). That is, when the cam member 11 rotates 50 turns, the circular spline 30 rotates one turn.

Meanwhile, the harmonic drive according to the present invention may further include a rear ring 51, an oil sealing 52, and a rear cover 60 coupled to the rear side of the house 40 as shown in FIGS. 1 to 3. have. As shown in FIG. 2, the rear ring 51 fixes a part of the cross roller bearing 53 fitted to the groove provided in the center of the outer circumferential surface of the circular spline 30 together with the house 40. The rear cover 60 is bolted to the rear of the circular spline 30.

Referring to the operation characteristics of the harmonic drive according to an embodiment of the present invention having such a configuration, first, when the elliptical cam member 11 is rotated by the input shaft, a wave is generated by the cam member 11, thus generated The wave causes shape deformation of the first and second

elastic bodies

21, 22 of the flexpline 20. In this process, the first teeth of the flexpline 20, that is, the plurality of pins 23 and the second teeth 32 formed on the body 31 of the circular spline 30 are partially engaged with each other. As the phase is deformed due to the difference between the number of pins 23 and the dimensions of the second tooth 32, the decelerated output through the circular spline 30 is transmitted to the output stage.

As described above, although the technical idea of the present invention has been described in detail in the preferred embodiments, this is for illustrative purposes, and in particular, the structure and shape of the wave generator and the circular spline except for the flexpline are not limited to the above-described embodiments. The structures and shapes applied to various types of harmonic drives, for example, component types of harmonic drives, unit types, gear head types or differential gear types, are applicable. As such, those skilled in the art may understand that various embodiments are possible through the combination of the embodiments of the present invention within the scope of the technical idea of the present invention.

10: wave generator 20: flexpline

30: Circular Spline 40: House

51: rear ring 52: oil sealing

53: cross roller bearing 60: rear cover

11

cap member

12, 13 bearing

14 snap ring 21 first elastic body

22: second elastic body 23: pin (first tooth type)

31 body 32: second tooth

Claims

First and second elastic bodies having a circular ring structure; And

In order to connect the first and second elastic bodies to each other in a mutually symmetrical structure, a plurality of pins having one side fastened to the first elastic body and the other side fastened to the second elastic body to form teeth.

Flexpline comprising a.
The method of claim 1,

The first and second elastic bodies are each made of a thermoplastic elastomer.
Wave generator;

In order to connect the first and second elastic bodies having a circular ring structure and the first and second elastic bodies to each other in a symmetrical structure, one side is fastened to the first elastic body and the other is fastened to the second elastic body. A flexpline including a plurality of pins forming a first tooth shape, wherein the way generator is inserted into and fastened to an inner circumferential surface thereof so as to deform the first and second elastic bodies by a wave generated from the wave generator; And

And a body having a circular ring structure in which a second tooth is formed on an inner circumferential surface into which the flexpline is inserted, wherein the second tooth is a first tooth of the flexpline by deformation of the first and second elastic bodies. Splines partially engaged with pins forming

Harmonic drive that includes.
The method of claim 3, wherein

The first and second elastic bodies are each harmonic drive made of a thermoplastic elastomer.
The method of claim 3, wherein

The wave generator,

An elliptical cam member coupled to the input shaft and interlocked with the input shaft to generate the wave; And

A bearing including an inner ring contacting the outer circumferential surface of the cam member, an outer ring contacting the inner circumferential surface of the flexplane, and a movable body provided between the inner ring and the outer ring to press the outer ring according to the rotation of the cam member.

Harmonic drive that includes.
The method of claim 3, wherein

And the second tooth has 2n (n is a natural number) more than the number of pins.