CN116838767A - Circumference split cam waveform generator - Google Patents

Abstract

The invention relates to a waveform generator, which is characterized in that: as a waveform generator for a harmonic reducer, a single cam is formed by alternately abutting a plurality of long-diameter side split cams and a number of short-diameter side split cams equal thereto in the circumferential direction, wherein the outer circumferential surface of the long-diameter side split cams has a constant circumferential surface with a smaller radius, and the outer circumferential surface of the short-diameter side split cams has a constant circumferential surface with a larger radius, and the circumferential surfaces of the long-diameter side split cams and the short-diameter side split cams have a common tangent line at a position where the circumferential surfaces intersect each other. Thereby, the shape of the cam surface of the waveform generator can be easily processed.

Description

Circumference split cam waveform generator

Technical Field

The present invention relates to a waveform generator which is one of the components of a harmonic reducer mainly applied to joints of an industrial robot, and more particularly, to an improved waveform generator capable of preventing occurrence of backlash or friction torque drop.

Background

In general, a harmonic reducer 10 applied to an industrial robot transmits high-speed rotation of a servo motor to an output shaft at a high reduction ratio of 1:30 to 1:320, and as shown in fig. 1, the core of the reduction is that when an elliptical waveform generator 11 rotates, a position where a flexible gear 12 surrounding the elliptical waveform generator is engaged with an outer rigid gear 13 moves in a circumferential direction and rotates in an opposite direction according to a difference in the number of teeth.

However, in the harmonic reducer according to the principle described above, backlash may occur due to tooth form design and machining errors, and gaps between tooth forms caused by wear of parts such as bearings.

In particular, since the waveform generator 11 has an elliptical cam shape, the precise machining of the outer shape thereof is very difficult, and thus, there is a problem in that it is difficult to realize mass production and the production unit price is excessively high. In addition, there is a problem in that a very expensive device is required also in precisely measuring the cam shape of the waveform generator 11. Further, since the flexible gear 12 is assembled to the waveform generator 11 in an elastically deformed state, there is a problem in that a skilled technique is required and productivity is low.

Further, in order to solve the problems as described above, the applicant has proposed inventions disclosed in korean patent No. 10-2303050 (publication date: 2021.09.16), korean patent No. 10-2345641 (publication date: 2021.12.31), and korean patent publication No. 10-2021-0155587 (publication date: 2021.12.23).

As shown in fig. 2, the core is to solve the tooth design and thus the backlash problem by converting the bond between the flexible gear 22 and the just-awake gear 23 into a friction structure.

However, even in the case described above, there is still a great problem in terms of processing of the cam-type waveform generator 21. In particular, when the vertical surface pressure V of the waveform generator 21 is not sufficiently transmitted to the flexible gear 22 side due to machining errors, abrasion of the friction surface, abrasion of the bearing, and the like, a sufficient friction torque cannot be generated due to a decrease in the friction force f with the rigid gear 23, and there is a further problem that the performance as a speed reducer cannot be ensured.

Disclosure of Invention

A first object of the present invention is to provide an improved waveform generator that is easy to shape.

A second object of the present invention is to provide a waveform generator capable of preventing occurrence of backlash not only in a toothed reduction gear but also in a non-toothed reduction gear, in which the transmitted vertical surface is depressed.

In order to achieve the above object, the present invention provides a waveform generator, which is characterized in that: as a waveform generator for a harmonic reducer, a single cam is formed by alternately abutting a plurality of long-diameter side split cams and a number of short-diameter side split cams equal thereto in the circumferential direction, wherein the outer circumferential surface of the long-diameter side split cams has a constant circumferential surface with a smaller radius, and the outer circumferential surface of the short-diameter side split cams has a constant circumferential surface with a larger radius, and the circumferential surfaces of the long-diameter side split cams and the short-diameter side split cams have a common tangent line at a position where the circumferential surfaces intersect each other.

Wherein the circumferential surfaces of the long-diameter side dividing cams and the short-diameter side dividing cams are connected to each other in the circumferential direction to form V-grooves and form a track along which a plurality of balls can be placed.

Alternatively, a plurality of rollers may be in rolling contact with the circumferential surface of the long-diameter side split cam and the circumferential surface of the short-diameter side split cam.

In this case, the circumferential surfaces of the long-diameter side split cam and the short-diameter side split cam are connected to each other in the circumferential direction at both sides thereof to form a partition wall that guides the rollers to prevent them from coming off the track, and form a single track along which the plurality of rollers can be placed.

Alternatively, a single flexible bearing inner race may be coupled to the circumferential surfaces of the plurality of long-diameter side split cams and the circumferential surfaces of the plurality of short-diameter side split cams, and a plurality of balls or rollers may be placed on the flexible bearing inner race.

In this case, a flexible bearing outer race may also be incorporated on the plurality of balls or rollers.

Further, a center shaft is attached to the inner sides of the plurality of long-diameter side split cams and short-diameter side split cams, tapered grooves inclined in the axial direction are formed between the inner peripheral surfaces of the plurality of long-diameter side split cams and short-diameter side split cams and the outer peripheral surface of the center shaft so as to extend in the circumferential direction, and a plurality of balls are inserted into the tapered grooves, and the plurality of balls are pressed in the axial direction by lock nuts coupled to the outer peripheral surface of the center shaft, whereby the positions of the plurality of long-diameter side split cams and short-diameter side split cams can be finely adjusted to the outside.

In this case, the long-diameter side split cam has a long hole formed adjacent to the outer peripheral surface of the long-diameter side split cam and extending in the circumferential direction, and the pressing force can be exerted in the radial direction by elastic deformation in which the width of the long hole is narrowed by a plurality of balls that press in the axial direction.

Alternatively, a center shaft is attached to the inner sides of the plurality of long-diameter side split cams and short-diameter side split cams, tapered grooves inclined in the axial direction are formed in the inner peripheral surfaces of the plurality of long-diameter side split cams and short-diameter side split cams, respectively, balls are inserted into the tapered grooves, and the positions of the plurality of long-diameter side split cams and short-diameter side split cams can be finely adjusted to the outside by pressing the balls in the axial direction by lock nuts coupled to the outer peripheral surfaces of the center shaft.

In this case, a flange for supporting the plurality of long-diameter side split cams and the short-diameter side split cams in the axial direction is formed to extend in the radial direction from one end of the center shaft, and the flange is elastically deformed in the axial direction by the plurality of long-diameter side split cams and the short-diameter side split cams pressed by the ball, so that it is possible to prevent excessive force from being transmitted in the radial direction by the plurality of long-diameter side split cams and the short-diameter side split cams.

As described above, according to the waveform generator to which the present invention is applied, since each of the outer peripheral surfaces of the long-diameter side split cam and the short-diameter side split cam has a circumferential surface of a certain radius, the outer peripheral surface of the split cam can be precisely machined simply, quickly and accurately by turning or grinding by means of simple rotation.

Further, by the configuration in which the balls are inserted into the tapered grooves between the split cams and the center shaft and pressed by the lock nuts, the split cams can be finely adjusted to the outside, and the flexible gears and the rigid gears coupled to the outside can be made to abut against each other, so that backlash can be prevented not only in the case of tooth-shaped coupling but also in the case of non-tooth-shaped coupling, vertical surface depression transmitted can be prevented.

Drawings

Fig. 1 is a front view and a detailed view of a toothed harmonic reducer to which the prior art is applied.

Fig. 2 is a front view and a detailed view of a non-toothed harmonic reducer applicable to the prior art.

Fig. 3 is a front view of a waveform generator to which an embodiment of the present invention is applied.

Fig. 4 is a front view illustrating a modification of the waveform generator of fig. 3.

Fig. 5 is a left side view of the waveform generator of fig. 3.

Fig. 6 to 8 are left side views illustrating a modification of the waveform generator of fig. 5.

Fig. 9 is a cross-sectional view of fig. 5.

Fig. 10 is a cross-sectional view illustrating a modification of fig. 9.

Fig. 11 is a partially exploded perspective view illustrating another modification of fig. 10.

Fig. 12 is a front view of a waveform generator to which another embodiment of the present invention is applied.

Fig. 13 is a front view for explaining the elastic portion of the long-diameter side split cam of fig. 12.

Fig. 14 is an oblique view illustrating a cut state of the waveform generator of fig. 12.

Fig. 15 is a front view and a cross-sectional view of a non-toothed harmonic reducer to which the waveform generator of fig. 3 is applied.

Fig. 16 is a front view and a cross-sectional view of a tooth harmonic reducer to which the waveform generator of fig. 12 is applied.

[ PREPARATION ] A method for producing a polypeptide

100: waveform generator

110: cam

111: long-diameter side dividing cam

111a: circumferential surface

111b: v-shaped groove

111c: partition wall

111d: an inner peripheral surface

111e: inner peripheral surface (taper surface)

111f: cone-shaped groove

111g: long hole

112: short-diameter side dividing cam

112a: circumferential surface

112b: v-shaped groove

112f: cone-shaped groove

120: ball with ball body

130: flexible bearing inner ring

140: flexible bearing outer ring

150: roller

160: center shaft

161: conical surface

162: flange

162a: notch

170: ball with ball body

180: lock nut

Detailed Description

As shown in fig. 3, the waveform generator 100 to which the embodiment of the present invention is applied is configured such that two long-diameter side split cams 111 and two short-diameter side split cams 112 are alternately abutted in the circumferential direction to form one cam 110.

The long-diameter side split cam 111 and the short-diameter side split cam 112 have circumferential surfaces 111a, 112a of a certain radius, that is, circular circumferential surfaces, respectively, wherein the long-diameter side split cam 111 has a circumferential surface 111a having a smaller radius r1, and the short-diameter side split cam 112 has a circumferential surface 112a having a larger radius r 2.

At this time, the long-diameter side split cam 111 and the short-diameter side split cam 112 have different centers O1, O2, respectively, and have a common tangent L to each other at the position where the respective circumferential surfaces 11a and 112a intersect, so that the circumferential surfaces 111a, 112a are smoothly connected. In this way, one cam circumferential surface composed of the four divided cams 111, 112 can be formed.

As shown in fig. 4, the cam using the combination of the split cams as described above may be realized by a combination of six split cams, that is, three long-diameter side split cams 111 'and three short-diameter side split cams 112', and the like may be applied to eight split cams.

In addition, in the combination of all the split cams, the circumferential surfaces 111a, 111a 'of the long-diameter side split cams 111, 111' will become the acting surfaces for the outer flexible gear (see 12 in fig. 1) or the rigid gear 13.

The plurality of balls 120 are to be in rolling contact along the circumferential surfaces 111a, 112a of the long-diameter side dividing cam 111 and the short-diameter side dividing cam 112, and for this purpose, V-shaped grooves 111b, 112b are formed in connection in the circumferential direction in the circumferential surfaces 111a, 112a as shown in fig. 5, so that the balls 120 can be placed along the track.

Alternatively, as shown in fig. 6, the flexible bearing inner ring 130 may be bonded to the circumferential surfaces 111a and 112a and the ball 120 may be placed thereon, or as shown in fig. 7, the flexible bearing outer ring 140 may be additionally bonded. The balls 120 and the inner and outer races 130 and 140 of fig. 6 and 7 may be replaced with rollers (not shown) and corresponding inner and outer races of the flexible bearings (not shown).

As another modification, as shown in fig. 8, a configuration may be adopted in which a plurality of rollers 150 are in rolling contact with the circumferential surfaces 111a, 112a of the long-diameter side dividing cam 111 and the short-diameter side dividing cam 112, and for this purpose, partition walls 111c having a constant width are formed on the circumferential surfaces 111a, 112a so as to be connected in the circumferential direction for ensuring smooth track circulation of the rollers 150, thereby ensuring that the mounted rollers 150 do not come off from the tracks on the circumferential surfaces 111a, 112a.

Further, in consideration of machining errors of the waveform generator 100, mounting errors in the decelerator, wear occurring during use, and the like, as shown in fig. 9, fine adjustment of the positions of the split cams 111, 112 in the radial direction can be performed by interposing the balls 170 between the split cams 111, 112 and the center shaft 160 thereof.

Specifically, the ball 170 may be inserted by forming a tapered groove H between the tapered surface 161 inclined on the outer peripheral surface of the center shaft 160 and the inner peripheral surfaces 111d of the split cams 111, 112. Further, by screwing the lock nut 180 to the outer peripheral surface of the center shaft 160, the ball 170 can be pressurized to the inside of the tapered groove H via the washer 181. Thereby, the positions of the outside, i.e., the radial direction, of the dividing cams 111, 112 can be adjusted by means of the balls 170 inserted inside the tapered grooves H.

As shown in fig. 10, the tapered groove H may be formed such that the outer peripheral surface of the central shaft 160' is formed with a circumferential surface having a constant radius, and the inner peripheral surfaces 111e of the split cams 111 and 112 are formed with tapered surfaces.

Alternatively, as shown in fig. 11, a configuration may be adopted in which tapered grooves 111f, 112f inclined in the axial direction are formed in the inner peripheral surfaces of the split cams 111, 112, and balls 170 'are inserted into the respective tapered grooves 111f, 112f to press with lock nuts (see 180' in fig. 10).

Further, in fig. 3, when a phenomenon in which a vertical surface is depressed or backlash occurs due to wear of a ball 120 or a roller and its bearing that circulate on the circumferential surfaces 111a, 112a of the split cams 111, 112 and/or wear of a flexible paper wheel (see 12 in fig. 1) or a rigid gear (see 13) coupled to the outside of the waveform generator 100, as a configuration in which compensation can be automatically performed, as shown in fig. 12 to 14, a long hole 111g formed to extend in the circumferential direction may be provided at an inner position adjacent to the circumferential surface 111a of the long-diameter side split cam 111.

In fig. 14, the split cam 111, which is forced outward by the ball 170 pressed by the lock nut 180, exerts pressing force on the ball 120 on the circumferential surface 111a by elastic deformation in which the width of the long hole 111g is narrowed. Thereby, the ball 120 will be more closely attached to the outer flexible gear (see 12 in fig. 1) and the rigid gear 13, thereby preventing the transmitted vertical surface from being depressed or from being kicked back.

At this time, in order to support the split cams 111 and 112, the notch 162a is formed in the base portion of the flange 162 formed by extending in the radial direction from the one end portion of the central shaft 160, and when the force of pressing the ball 170 by the lock nut 180 is excessive, the flange 162 can be elastically deformed in the axial direction (left direction in fig. 14), so that the excessive force can be prevented from being directly transmitted to the split cams 111 and 112.

In the present embodiment, the configuration in which the notch 162a is formed for elastic deformation in the axial direction of the flange 162 is adopted, but the present invention is not limited to the configuration described above, and various means such as a method in which elastic deformation is more easily achieved by reducing the thickness of the flange 162 may be applied instead of the configuration described above.

The structure in which the flange 160 is elastically deformed as described above may be applied to a structure in which the long hole 111g is not formed in the dividing cam 111 as shown in fig. 10.

Fig. 15 shows a non-toothed harmonic reducer 200 to which the waveform generator 100 of fig. 3 and 10 is applied, in which a flexible gear 210 is rotated in a reverse direction by rolling motion on the inner peripheral surface of a rigid gear 220 by vertical surface pressure of a ball 120 outside split cams 111, 112, and the driven shaft 230 is driven to rotate at a high reduction ratio with respect to a drive shaft (i.e., a central shaft 160).

Fig. 16 shows a tooth harmonic reducer 300 to which the waveform generator of fig. 12 and 14 is applied, in which a flexible gear 310 is rotated in a reverse direction by a difference in the number of teeth of the flexible gear 310 while being brought into close engagement with a rigid gear 320 by the pressing action of a ball 120 outside the split cams 111 and 112, and the driven shaft 330 is driven to rotate at a high reduction ratio.

The waveform generator described in the foregoing is merely to aid in understanding an embodiment of the present invention, and thus the scope of the claims and technical scope of the present invention defined by the appended claims should not be limited to the description described in the foregoing.

Claims (10)

1. A waveform generator, characterized by:

as a waveform generator for a harmonic reducer,

a cam is formed by alternately abutting a plurality of long-diameter side divided cams and a same number of short-diameter side divided cams along the circumferential direction,

wherein the outer circumferential surface of the long-diameter side dividing cam has a certain circumferential surface with a smaller radius,

the outer circumferential surface of the short-diameter side dividing cam has a certain circumferential surface with a larger radius,

the circumferential surfaces of the long-diameter side split cams and the short-diameter side split cams have a common tangent line at a position where they intersect with each other.

2. The waveform generator of claim 1, wherein:

the circumferential surfaces of the long-diameter side dividing cams and the short-diameter side dividing cams are connected to each other in the circumferential direction to form a V-shaped groove and form a track,

a plurality of balls are positioned along the track.

3. The waveform generator of claim 1, wherein:

a plurality of rollers are in rolling contact with the circumferential surface of the long-diameter side split cam and the circumferential surface of the short-diameter side split cam.

4. A waveform generator as claimed in claim 3, wherein:

the two sides on the circumference of the long-diameter side dividing cam and the short-diameter side dividing cam are connected with each other along the circumference direction to form a dividing wall which prevents the roller from separating from the track by guiding the roller and form a track,

the plurality of rollers are disposed along the track.

5. The waveform generator of claim 1, wherein:

a flexible bearing inner ring is combined on the circumferential surfaces of the long-diameter side dividing cams and the short-diameter side dividing cams,

a plurality of balls or rollers are disposed on the flexible bearing inner race.

6. The waveform generator of claim 5, wherein:

a flexible bearing outer race is also coupled to the plurality of balls or rollers.

7. The waveform generator of claim 1, wherein:

a central shaft is mounted on the inner side of the plurality of long-diameter side dividing cams and the short-diameter side dividing cams,

tapered grooves inclined in the axial direction are formed between the inner peripheral surfaces of the plurality of long-diameter side dividing cams and the short-diameter side dividing cams and the outer peripheral surface of the center shaft so as to extend in the circumferential direction,

a plurality of balls are inserted into the tapered groove,

the positions of the plurality of long-diameter side dividing cams and the short-diameter side dividing cams are finely adjusted to the outside by pressing the plurality of balls in the axial direction by a lock nut coupled to the outer peripheral surface of the center shaft.

8. The waveform generator of claim 7, wherein:

the long-diameter side split cam has a long hole formed adjacent to an outer peripheral surface of the long-diameter side split cam and extending in a circumferential direction, so that a pressing force is exerted in a radial direction by elastic deformation in which a width of the long hole is narrowed by a plurality of balls that press in the axial direction.

9. The waveform generator of claim 1, wherein:

a central shaft is mounted on the inner side of the plurality of long-diameter side dividing cams and the short-diameter side dividing cams,

tapered grooves inclined in the axial direction are formed in the inner peripheral surfaces of the plurality of long-diameter side split cams and the short-diameter side split cams,

a ball is inserted into the conical groove,

the positions of the plurality of long-diameter side dividing cams and the plurality of short-diameter side dividing cams are finely adjusted to the outside by pressing the ball in the axial direction by a lock nut coupled to the outer peripheral surface of the center shaft.

10. The waveform generator of claim 7, wherein:

a flange extending radially from one end of the central shaft to support the plurality of long-diameter side split cams and the short-diameter side split cams in the axial direction,

the flange is elastically deformed in the axial direction by the plurality of long-diameter side split cams and short-diameter side split cams pressed by the ball, thereby preventing excessive force from being transmitted in the radial direction by the plurality of long-diameter side split cams and short-diameter side split cams.