KR200494613Y1 - Eccentric drive mechanism of a gear reducer - Google Patents

Abstract

The eccentric drive mechanism of the gear reducer includes an input shaft 2 having an outer section 21 , a coupling section 22 and an inner section 23 adjacent to each other in the axial direction. An annular groove 212 is formed in the outer peripheral surface 211 of the outer section 21 for mounting the radially projecting peripheral ring 41 . A plurality of rollers 31 are in rollable contact with the coupling peripheral surface 221 of the coupling section 22 , and are formed between the peripheral ring 41 and the inner section 23 .

Description

Eccentric drive mechanism of gear reducer {ECCENTRIC DRIVE MECHANISM OF A GEAR REDUCER}

The present invention relates to an eccentric gear reducer, and more particularly, to an eccentric drive mechanism of the gear reducer.

Referring to FIG. 1 , the conventional gear reducer disclosed in US Pat. No. 7,901,317 includes an input shaft 111 , first and second gears 118 and 119 surrounding the input shaft 111 , and an input shaft 111 . ) and a plurality of first rollers 112 that are in rollable contact with the first gear 118 and are angularly displaced from each other, and the input shaft 111 and the second gear 119 in rollable contact with each other at an angle a first retainer disposed to support the first roller 112 thereon to maintain a gap between the plurality of second rollers 113 displaced in the circumferential direction and two adjacent first rollers 112 in the circumferential direction; 114 , and a second retainer 115 arranged to support the second roller 113 thereon to maintain a gap between two adjacent second rollers 113 in the circumferential direction. The input shaft 111 has first and second annular grooves 116 and 117 formed in its circumferential surface for rollably receiving and retaining the first and second rollers 112 and 113, respectively. The axial lengths of the first and second annular grooves 116 , 117 are similar to the axial lengths of the corresponding first and second rollers 112 , 113 , so that the axial movement of the rollers 112 , 113 is limited. . When the input shaft 111 is rotated, the first and second rollers 112 , 113 rotate in corresponding first and second annular grooves 116 , 117 to allow torque transmission to thereby engage the gears 118 , 119 . vibrate

However, the correct formation of the first and second annular grooves 116 and 117 in the input shaft 111 not only suppresses the axial movement of the rollers 112 and 113 but also permits their rolling, increasing the manufacturing cost. In addition, wear on the two sides of the annular grooves 116 and 117 can easily occur during use, thereby damaging the speed reducer due to shock and vibration.

Referring to FIG. 2 , another conventional gear reducer disclosed in Japanese Patent Laid-Open No. 2006-071017 A is mounted with an input shaft 121 and inner races 1221 and 1231 in contact with each other in the axial direction. To support the first bearing 122 and the second bearing 123, a plurality of rollers 124 in rollable contact with the inner race 1231 and angularly displaced from each other, and the rollers 124 thereon. and a retainer 125 disposed thereon. An annular groove 126 is formed in the inner race 1231 to receive and hold the roller 124 in a rollable manner. The axial length of the annular groove 126 is similar to the length of the roller 124 , so that the axial movement of the roller 124 is limited. When the input shaft 121 rotates, the first bearing 122 and inner race 1231 rotate, causing the roller 124 to rotate within the annular groove 126 for torque transmission. Similarly, the correct formation of the annular groove 126 in the inner race 1231 not only inhibits the axial movement of the roller 124 but also allows its rolling, and wear of the inner race 1231 can easily occur during use. have. Also, the inner race 1231 needs to be assembled to the input shaft 121, increasing the cost of assembly.

Accordingly, it is an object of the present disclosure to provide an eccentric drive mechanism of a gear reducer that can alleviate at least one of the disadvantages of the prior art.

According to the disclosure, an eccentric drive mechanism is mounted on a gear reducer comprising a first gear. The eccentric drive mechanism includes an input shaft, a roller assembly and a motion limiting assembly. The input shaft extends in an axial direction of a first axis and has a first outer section, a first coupling section and a first inner section adjacent to each other in the axial direction. The first outer section has a first outer peripheral surface surrounding the first axis and a first annular groove formed in the first outer peripheral surface and adjacent the first coupling section. The first coupling section has a first coupling peripheral surface surrounding a first axis and penetrating a first gear, the first inner section defining an outer diameter greater than an outer diameter of the first coupling peripheral surface . The roller assembly includes a plurality of first rollers in rollable contact with the first coupling peripheral surface and the first gear and angularly displaced from each other about a first axis, the plurality of first rollers surrounding the first coupling peripheral surface; and a first retainer supporting the first roller therearound to maintain a gap between adjacent two of the first rollers in the circumferential direction and permit rolling of the first roller. Each of the first rollers defines a first length in the axial direction that is less than and different from the length of the first coupling peripheral surface in the axial direction by a first distance. The first distance is greater than 0.005 times the first length and less than 0.05 times the first length. The motion limiting member includes an inner peripheral ring portion disposed in the first annular groove, and an outer projecting radially and outwardly of the first annular groove and having an outer diameter greater than an outer diameter of the first coupling peripheral surface. and a peripheral ring portion such that movement of the first roller in the axial direction is limited by the first peripheral ring and the first inner section.

Other features and advantages of the present disclosure will become apparent from the following detailed description of embodiments with reference to the accompanying drawings.
1 is a schematic diagram of a conventional gear reducer.
2 is a schematic diagram of another conventional gear reducer.
3 is a perspective view illustrating an embodiment of an eccentric drive mechanism mounted on a gear reducer according to the present disclosure;
4 is a perspective view of the gear reducer taken from another angle;
5 and 6 are exploded perspective views of the gear reducer.
7 is a partial cross-sectional view of an embodiment.

3 to 5 , one embodiment of an eccentric drive mechanism according to the present disclosure is shown to be mounted on a gear reducer. The gear reducer is a first gear 91, a first Oldham coupler 92 driven and rotated by the first gear 91, and a first flange coupler 93 driven and rotated by a first Oldham coupler 92 , a second gear 94, a second Oldham coupler 95 driven and rotated by the second gear 94, and a second flange coupler 96 driven and rotated by a second Oldham coupler 95 include

4 to 6, when the first and second gears 91 and 94 are driven to have a cycloidal motion, the first and second Oldham couplers 92 and 95 are coupled to the first and second flange couplers ( 93 and 96 respectively rotated at reduced speeds to correspondingly transmit torque from them. This gear reducer with Oldham coupling is of the pneumatic type, and a detailed description of its structure is omitted herein.

5-7 , the eccentric drive mechanism includes an input shaft 2 , a roller assembly 3 and a motion limiting assembly 4 .

The input shaft 2 extends in the axial direction of the first axis L1 and has a first outer section 21 , a first coupling section 22 and a first inner section 23 adjacent to each other in the axial direction. do. Further, the input shaft 2 extends towards the first inner section 23 in the axial direction of a second axis L2 parallel to the first axis L1 and non-coaxial with the first axis L1, It has a second outer section 24 , a second coupling section 25 and a second inner section 26 adjacent to each other in the axial direction.

The first outer section 21 has a first outer peripheral surface 211 surrounding the first axis L1 , and a first formed on the first outer peripheral surface 211 and adjacent to the first coupling section 22 . An annular groove 212 is provided. The first coupling section 22 has a first coupling peripheral surface 221 surrounding the first axis L1 and passing through the first gear 91 . The first inner section 23 defines an outer diameter greater than the outer diameter of the first coupling peripheral surface 221 .

The second outer section 24 has a second outer peripheral surface 241 surrounding the second axis L2 and a second formed on the second outer peripheral surface 241 and adjacent the second coupling section 25 . An annular groove 242 is provided. The second coupling section 25 has a second coupling peripheral surface 251 surrounding the second axis L2 and passing through the second gear 94 . The second inner section 26 is adjacent to the first inner section 23 and defines an outer diameter greater than the outer diameter of the second coupling peripheral surface 251 .

The roller assembly 3 comprises a plurality of first rollers in rollable contact with the first coupling peripheral surface 221 and the first gear 91 and angularly displaced from each other about the first axis L1 . (31) and surrounding the first coupling peripheral surface (221) and to maintain a gap between two adjacent ones of the first roller (31) in the circumferential direction and to allow rolling of the first roller (31) A first retainer 32 supporting a first roller 31 therearound, a second coupling peripheral surface 251 and a second gear 94 in rollable contact, and a second axis L2 a plurality of second rollers 33 angularly displaced from each other about the center, and a gap between two adjacent ones of the second rollers 33 surrounding the second coupling peripheral surface 251 and in the circumferential direction and a second retainer (34) for holding and supporting the second roller (33) therearound to permit rolling of the second roller (33). In this embodiment, each first roller 31 has a cylindrical shape and is rotated about its axis parallel to the first axis L1 . Each second roller 33 has a cylindrical shape and is rotated about its axis parallel to the second axis L2.

Each first roller 31 defines in the axial direction a first length X1 of a length different and smaller than the length of the first coupling peripheral surface 221 in the axial direction by a first distance G1 . The first distance G1 is greater than 0.005 times the first length X1 and less than 0.05 times the first length X1. The first retainer 32 has an inner retainer peripheral surface 321 facing the first axis L1 . Each second roller 33 defines in the axial direction a second length X2 of a different length which is smaller than the length of the second coupling peripheral surface 251 in the axial direction by a second distance G2 . The second distance G2 is greater than 0.005 times the second length X2 and less than 0.05 times the second length X2. The second retainer 34 has an inner retainer peripheral surface 341 facing the second axis L2 .

The motion restriction assembly 4 comprises a first perimeter ring 41 and a second perimeter ring 42 . The first peripheral ring 41 has an inner peripheral ring portion 411 disposed in the first annular groove 212 , and projects radially and outwardly of the first annular groove 212 and includes a first coupling peripheral surface and an outer peripheral ring portion 412 having an outer diameter greater than the outer diameter of 221 . Similarly, the second peripheral ring 42 has an inner peripheral ring portion 421 disposed in the second annular groove 242, radially and outwardly of the second annular groove 242, and a second couple and an outer perimeter ring portion 422 having an outer diameter greater than the outer diameter of the ring perimeter surface 251 .

Accordingly, the movement of the first roller 31 in the axial direction is limited by the first peripheral ring 41 and the first inner section 23 , and the movement of the second roller 33 in the axial direction is limited by the second peripheral ring (42) and a second inner section (26). In other words, a first roller 31 having a first length X1 that is less than the length of the first coupling peripheral surface 221 along a first axis L1 and a second roller 31 along a second axis L2 With the second roller 33 having a second length X2 that is smaller than the length of the coupling peripheral surface 251 , wear of the ends of each of the first and second rollers 31 , 33 is minimized. Also, the first and second distances G1 and G2 are provided to allow thermal expansion of the first and second rollers 31 and 33 .

The outer diameter of the outer peripheral ring portion 412 of the first peripheral ring 41 is smaller than the inner diameter of the inner retainer peripheral surface 321 of the first retainer 32 , and the outer peripheral ring portion of the second peripheral ring 42 . The outer diameter of 422 is less than the inner diameter of the inner retainer peripheral surface 341 of the second retainer 34 . In this embodiment, each of the first and second peripheral rings 41 , 42 is made of an elastomeric material to be formed as a single piece.

When the input shaft 2 is driven and rotated, the first and second coupling sections 22 , 25 cause the first and second rollers to cause a cycloidal motion of the first and second gears 91 , 94 . (31, 33) rotated eccentrically to roll respectively.

Since the axial length of each roller 31 is less than the length of the first coupling peripheral surface 221 along the first axis L1 and the axial length of each second roller 33 is equal to the length of the second axis L2 ), the first roller 31 is rollable within the zone formed by the first inner section 23 and the first peripheral ring 41, The second roller 33 is rollable in the zone formed by the second inner section 26 and the second peripheral ring 42 , so that on two sides of the first and second rollers 31 , 33 different parts It is possible to avoid their wear and impact by not interfering with the parts.

Also, it is only necessary that the first and second coupling peripheral surfaces 221 , 251 of the input shaft 2 have an extended length longer than that of the first and second rollers 31 , 33 , which is precision machining. This makes manufacturing easy and convenient without the need, thereby reducing manufacturing costs.

The eccentric drive mechanism of the present disclosure may be mounted on a gear reducer having an Oldham coupling, but may be applied to other types of gear reducers. Also, the roller assembly 3 may include only a selected one of the first and second rollers 31 and 33 .

As shown, a first roller 31 having an axial length less than the first coupling peripheral surface 221 along a first axis L1 and a second coupling perimeter along a second axis L2 With the second roller 33 having an axial length smaller than the length of the surface 251 , the wear of the first and second rollers 31 , 33 respectively is minimized.

While the present disclosure has been described with respect to what are considered exemplary embodiments, this disclosure is not limited to the described embodiments, but it is intended to embrace various configurations included within the spirit and scope of the broadest interpretation to embrace all such modifications and equivalent arrangements. It is understood that it is intended to cover.

2: input shaft 21: first outer section
22: first coupling section 23: first inner section
24: second outer section 25: second coupling section
26: second inner section 31: first roller
32: first retainer 33: third roller
34: second retainer 41: first peripheral ring
42: second peripheral ring 91: first gear
94: second gear 212: first annular groove
221: first coupling peripheral surface 242: second annular groove
251: second coupling peripheral surface

Claims (6)

An eccentric drive mechanism for a gear reducer, the gear reducer comprising a first gear, the eccentric drive mechanism comprising:
an input shaft extending in an axial direction of a first axis and having a first outer section, a first coupling section and a first inner section adjacent to each other in the axial direction, wherein the first outer section is a first outer section surrounding the first axis a first annular groove formed in the first outer peripheral surface and adjacent the first coupling section, the first coupling section surrounding the first axis and passing through the first gear a coupling peripheral surface, the first inner section defining an outer diameter greater than an outer diameter of the first coupling peripheral surface;
a plurality of first rollers in rollable contact with the first coupling peripheral surface and the first gear and angularly displaced from each other about a first axis, surrounding the first coupling peripheral surface and circumferentially a roller assembly having a first retainer supporting the first roller therearound to maintain a gap between adjacent two of the first rollers in direction and permit rolling of the first roller, the first roller each defining in the axial direction a first length of a different length and less than the length of the first coupling peripheral surface in the axial direction by a first distance, the first distance greater than 0.005 times the first length, and 0.05 of the first length smaller than a ship ―; and
an inner peripheral ring portion disposed in the first annular groove and an outer peripheral ring portion projecting radially and outwardly of the first annular groove and having an outer diameter greater than an outer diameter of the first coupling peripheral surface; and a motion limiting assembly having a first peripheral ring such that motion of the first roller in an axial direction is limited by the first peripheral ring and the first inner section.
Eccentric drive mechanism. The method of claim 1,
wherein said first retainer has an inner retainer peripheral surface facing a first axis, wherein an outer diameter of said outer peripheral ring portion of said first peripheral ring is less than an inner diameter of said inner retainer peripheral surface.
Eccentric drive mechanism. The method of claim 1,
wherein said first peripheral ring is made of an elastomeric material to be formed as a single piece.
Eccentric drive mechanism. The method of claim 1,
The gear reducer further comprises a second gear,
The input shaft also extends in an axial direction of a second axis parallel to the first axis and non-coaxial with the first axis towards the first inner section, a second outer section adjacent to each other in the axial direction, a second coupling a section and a second inner section, the second outer section having a second outer peripheral surface surrounding a second axis and a second annular groove formed in the second outer peripheral surface and adjacent the second coupling section wherein the second coupling section has a second coupling peripheral surface surrounding a second axis and penetrating a second gear, the second inner section adjacent the first inner section, and 2 to form an outer diameter greater than the outer diameter of the surface around the coupling;
The roller assembly includes a plurality of second rollers in rollable contact with the second coupling peripheral surface and the second gear and angularly displaced from each other about a second axis, the second coupling peripheral surface; and a second retainer surrounding the second roller and supporting the second roller therearound to maintain a gap between adjacent two of the second rollers in the circumferential direction and permit rolling of the second roller; each of the second rollers defines in the axial direction a second length of a different length and less than the length of the second coupling peripheral surface in the axial direction by a second distance, the second distance being greater than 0.005 times the second length; 2 less than 0.05 times the length,
wherein the motion limiting assembly has an inner peripheral ring portion disposed in the second annular groove and an outer diameter projecting radially and outwardly of the second annular groove and greater than an outer diameter of the second coupling peripheral surface; and a second peripheral ring having an outer peripheral ring portion such that movement of the second roller in the axial direction is limited by the second peripheral ring and the second inner section.
Eccentric drive mechanism. 5. The method of claim 4,
the first retainer has an inner retainer peripheral surface facing a first axis, wherein an outer diameter of the outer peripheral ring portion of the first peripheral ring is less than an inner diameter of the inner retainer peripheral surface of the first retainer, wherein the second retainer has an inner retainer peripheral surface facing a second axis, wherein an outer diameter of the outer peripheral ring portion of the second peripheral ring is smaller than an inner diameter of the inner retainer peripheral surface of the second retainer.
Eccentric drive mechanism. 5. The method of claim 4,
wherein each of said first and second peripheral rings is made of an elastomeric material to be formed as a single piece.
Eccentric drive mechanism.

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