JP2008014500A - Reduction gear device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reduction gear device of low noise capable of reducing energy loss though it is compact and has a simple structure. <P>SOLUTION: Since this reduction gear device is provided with only gears of two stages, that is, a large-diameter gear 65 and a small-diameter gear 66 of a third external gear 63 supported on a supporting shaft 59, and a second external gear 58 of one stage engaged with the small-diameter gear 66 and disposed on one axial end of a crankshaft 40, the total axial length of the reduction gear device can be reduced, and the device can be miniaturized. Further since the gears are engaged only at two places in transmitting driving force from a first external gear 54 to the crankshaft 40, noise can be reduced, and energy loss can be lowered. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to a reduction gear that combines a front stage reduction gear composed of an external gear and an eccentric oscillating reduction gear.

As a conventional speed reducer, for example, one described in Patent Document 1 below is known.
JP-A-62-2586

  This is supported by an eccentric oscillating speed reducer having a plurality of crankshafts that are rotatably supported by a carrier at both ends in the axial direction and equidistant from each other in the circumferential direction, and attached to the output shaft of the motor. A first external gear that rotates by transmitting a driving force; a second external gear attached to one axial end of all crankshafts; and a second external gear rotatably supported by the output shaft of the motor. And a third external gear having a smaller diameter than the second external gear and a third external gear having a large diameter gear, and coaxial with the second external gear at one axial end of all the crankshafts While maintaining close relationship and meshing with the first external gear, the large-diameter gear having a larger diameter than the first external gear, and meshing with the large-diameter gear of the third external gear, the large-diameter gear Smaller diameter gear with smaller diameter It is obtained by rotatably supporting the fourth external gears that.

    However, in such a conventional speed reducer, three stages of external gears, that is, the second external gear, the large external gear of the fourth external gear, and the small external gear are coaxially arranged at one axial end of all crankshafts. Since it is arranged close to each other while maintaining the relationship, the axial length of the entire speed reducer becomes longer and larger, and three gears are required until the driving force is transmitted from the first external gear to the crankshaft. That is, the first external gear and the large external gear of the fourth external gear, the small external gear of the fourth external gear and the large external gear of the third external gear, the small external gear of the third external gear and the second external gear mesh with each other. As a result, there was a problem that noise was increased and energy loss was increased. Furthermore, since two types of gears (third and fourth external gears) having a large diameter gear and a small diameter gear are used, there is a problem that the structure becomes complicated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a low-noise reduction device that has a simple structure and a small size, and that has little energy loss.

    For this purpose, both ends in the axial direction are rotatably supported by the carrier, and an eccentric oscillating speed reducer having a plurality of crankshafts equidistant from each other in the circumferential direction, and a driving force transmitted from the motor to rotate. A first external gear, a second external gear attached to one axial end of at least one crankshaft, a support shaft supported by a carrier, and a first external gear supported by the support shaft. A large-diameter gear having a larger diameter than the first external gear, and a rotatable third external gear having a small-diameter gear meshing with the second external gear and having a smaller diameter than the second external gear. This can be achieved by the speed reducer provided.

  In the present invention, as described above, the support shaft supported by the carrier supports two-stage gears, that is, the large-diameter gear and the small-diameter gear of the third external gear. Since only one stage of the second external gear meshing with the small-diameter gear is attached, the axial length of the entire reduction gear is shortened, and the size can be reduced. In addition, there are two gears until the driving force is transmitted from the first external gear to the crankshaft, that is, the large-diameter gear of the first external gear and the third external gear, the small-diameter gear of the third external gear, and the second gear. Since it only meshes with the external gear, noise can be reduced and energy loss can be reduced. Furthermore, since only one type of the third external gear has the large-diameter gear and the small-diameter gear, the structure can be simplified.

According to the second aspect of the present invention, the diameter of the large-diameter gear of the third external gear can be further increased, whereby the reduction ratio of the reduction gear can be easily increased. .
Furthermore, if comprised as claimed in claim 3, the fastening member can be shared for both the fastening of the carrier and the support of the third external gear, thereby simplifying the structure and reducing the production cost. You can also

Embodiment 1 of the present invention will be described below with reference to the drawings.
In FIGS. 1, 2, and 3, reference numeral 11 denotes a proximal end arm as a first member of the industrial robot 12, and the proximal end arm 11 can swing around the proximal end portion. A fixed portion of an eccentric oscillating speed reducer 13, here a case 14 is fixed by a plurality of bolts 15 on one side surface of the distal end portion of the base side arm 11, and a rotating portion of the eccentric oscillating speed reducer 13 Here, at one side end of the carrier 16, a base end portion of a distal end side arm 17 as a second member of the industrial robot 12 is fixed by a plurality of bolts 18.

  As a result, the distal end side arm 17 can rotate (swing) with respect to the proximal end side arm 11 around the proximal end portion. As described above, when the case 14 is on the fixed side and the carrier 16 is on the rotating side, it is the same as the conventional type and can be used in the same manner as in the past. Here, the case 14 has a substantially cylindrical shape, and a plurality of pin teeth 21 as inner teeth that are equidistant from each other in the circumferential direction are provided on the inner periphery of the central portion in the axial direction.

  A plurality (two) of pinions 22 are accommodated in the case 14 so as to be arranged in the axial direction, and outer teeth 23 each having a large number of trochoidal teeth are formed on the outer periphery of the pinions 22. Here, the number of teeth of the external teeth 23 of the pinion 22 is slightly smaller than the number of teeth of the pin teeth 21, and here, only one, and the external teeth 23 are in contact with the pinion 22 and the case 14. Although the pin teeth 21 are engaged with each other, the phase of the maximum engagement portion (the deepest engagement portion) of the two pinions 22 is shifted by 180 degrees.

  A central hole 24 penetrating on the central axis of the pinion 22 and a plurality of (three) through holes (not shown) penetrating in the axial direction in the intermediate portion between the outer circumferences are circumferentially provided. Are formed equidistant from each other. Further, the carrier 16 is inserted into the case 14, and this carrier 16 has a pair of end plate portions 28 and 29 disposed on both outer sides in the axial direction of the pinion 22, and one end thereof is connected to the end plate portion 28. It is composed of a plurality of (the same number of through-holes) pillars (not shown) that are integrally formed and the other end fastened to the end plate part 29, and these pillars are loosely fitted in the through-holes, respectively. . Further, center holes 32 and 33 having substantially the same diameter as the center hole 24 are formed on the center axis of the carrier 16, specifically, the end plate portions 28 and 29.

  36 is a pair of bearings interposed between the outer periphery of the carrier 16, more specifically, the end plate portions 28 and 29 and the inner periphery of both ends in the axial direction of the case 14, and the carrier 16 is attached to the case 14 by these bearings 36. It is supported so as to be relatively rotatable. Reference numeral 37 denotes a plurality of (three) penetrating crank holes formed in each pinion 22 extending in the axial direction. These crank holes 37 are equidistant from each other in the circumferential direction and are alternately arranged with the through holes. .

  Reference numeral 40 denotes a plurality of crankshafts (the same number as the crank holes 37), and these crankshafts 40 are arranged equidistantly in the circumferential direction. A pair of bearings 41 separated in the axial direction are interposed between the crankshaft 40 and the carrier 16, more specifically, the end plate portions 28 and 29. The carrier 16 is rotatably supported via a pair of bearings 41.

  In addition, the crankshaft 40 has the same number (two) of eccentric portions 44 as the pinions 22 eccentrically spaced from the central axis of the crankshaft 40 at the axially central portion, and these eccentric portions 44 are adjacent to each other in the axial direction. And are out of phase with each other by 180 degrees. The eccentric portion 44 of the crankshaft 40 is inserted into the crank hole 37 of the pinion 22 via a roller bearing 45, respectively. As a result, the pinion 22 and the crankshaft 40 are allowed to rotate relative to each other. . Reference numeral 46 denotes an oil seal interposed between the inner periphery of the case 14 on the one side in the axial direction with respect to the bearing 36 disposed on one side in the axial direction and the outer periphery of the carrier 16, more specifically the end plate portion 28.

  The eccentric oscillating speed reducer that decelerates the rotation input to the crankshaft 40 and outputs it to the case 14 or the carrier 16, here the carrier 16, as a whole, the case 14, the carrier 16, the pinion 22, and the crankshaft 40. Configure 13 48 is a motor attached to the other side surface by a plurality of bolts 49 at the distal end portion of the base end side arm 11, and the rotating shaft 50 of this motor 48 is coaxial with the central axis of the eccentric oscillating speed reducer 13. . Thus, if the motor 48 and the eccentric oscillating speed reducer 13 are coaxial, compared with the case where the motor is installed at a predetermined distance in the radial direction from the central axis of the eccentric oscillating speed reducer, the turning portion The entire structure can be reduced in size.

  A transmission shaft 53 that passes through center holes 24, 32, 33 formed in the central portion of the eccentric oscillating speed reducer 13 in the axial direction is fixed to the rotary shaft 50, and the tip (one end) of the transmission shaft 53 is fixed. Is provided with one first external gear 54. The rotary shaft 50 and the transmission shaft 53 described above constitute the output shaft 55 of the motor 48 that extends in the central holes 24, 32, 33 toward one side in the axial direction, and the first shaft provided on the output shaft 55 is provided. When the driving force from the motor 48 is transmitted, the external gear 54 rotates around the axis.

  58 is a second external gear attached to at least one of them, here, one end of each crankshaft 40 in the axial direction (one end in the axial direction) by spline coupling. Reference numeral 59 denotes at least one support shaft extending in parallel with the output shaft 55, here three support shafts, which is the same number as the second external gear 58. These support shafts 59 are equidistant from each other in the circumferential direction. The side portion is supported by the carrier 16 by being inserted and fixed to the carrier 16, specifically, the end plate portion 28.

  The support shaft 59 is disposed at a position apart from the crankshaft 40 to which the second external gear 58 is attached, here, as described above, in the circumferential direction. It is arranged close to one side in the circumferential direction, and is arranged radially outside the virtual circle 60 passing through the central axis of all crankshafts 40. Reference numeral 63 denotes a third external gear coaxial with the support shaft 59 rotatably supported on one axial side portion of each support shaft 59 via a bearing 64. These third external gears 63 are on one axial side. A large-diameter gear 65 having a larger diameter than the first external gear 54 is provided, and all the large-diameter gears 65 are arranged around the one first external gear 54 and the one first gear. It meshes with the external gear 54.

  Here, the large-diameter gear 65 has a maximum diameter that does not interfere with each other. As a result, a large reduction ratio can be obtained by meshing the first external gear 54 and the large-diameter gear 65. The third external gear 63 has a small-diameter gear 66 on the other side in the axial direction, and the small-diameter gear 66 is disposed close to the large-diameter gear 65 in a coaxial relationship. These small-diameter gears 66 are smaller in diameter than the second external gear 58 and mesh with the corresponding second external gears 58, respectively.

  The first external gear 54 and the large diameter gear 65 of the third external gear 63 as a whole are the first stage gear reduction mechanism 67, and the small diameter gear 66 and the second external gear 58 of the third external gear 63 are as a whole. A second-stage gear reduction mechanism 68 is configured, and the first and second-stage gear reduction mechanisms 67 and 68 as a whole configure a front-stage reduction gear 69 disposed in the front stage of the eccentric oscillating reduction gear 13. Here, as described above, since the support shaft 59 is disposed radially outward from the virtual circle 60 passing through the central axis of all the crankshafts 40, the diameter of the large-diameter gear 65 of the third external gear 63 is further increased. Thereby, the reduction ratio of the reduction gear can be easily increased. The aforementioned support shaft 59 is disposed on or in the vicinity of the intermediate position in the circumferential direction of the adjacent crankshaft 40, so that the small-diameter gear 66 can be placed on the adjacent second external gear 58 or on the one side of the second external gear 58. The two external gears 58 may be engaged with each other. In this way, the second external gear 58 has a larger diameter, and the reduction ratio of the second stage gear reduction mechanism 68 can be further increased.

  Further, when the large-diameter gear 65 is formed to have the maximum diameter that does not interfere with each other as described above, the case 14 is provided on one side of the end plate portion 28 in the axial direction so as to surround the large-diameter gear 65 from the outside. An outer flange 71 projecting radially outward from the outer periphery of the central portion of the oil seal 46 is formed, but when the outer flange 71 is formed in this way, the open side of the oil seal 46, that is, one side in the axial direction is the outer flange 71. Nearly closed by the side flange 71, the entry of dust into the eccentric oscillating speed reducer 13 is effectively suppressed. Further, since the bolt 18 described above is fastened together with the outer flange 71 and the distal arm 17, the radial distance from the central axis of the eccentric oscillating speed reducer 13 to the bolt 18 is increased, and the eccentric oscillation is increased. The transmission torque from the dynamic reduction gear 13 to the distal arm 17 can be increased.

Next, the operation of the first embodiment will be described.
When the distal arm 17 is rotated (oscillated) with respect to the proximal arm 11 in the industrial robot 12 as described above, the motor 48 is operated to rotate the output shaft 55. The rotation of the output shaft 55 is decelerated one after another by the large diameter gear 65 of the first external gear 54 and the third external gear 63 and then by the small diameter gear 66 and the second external gear 58 of the third external gear 63. The crankshaft 40 is transmitted to all the crankshafts 40, and these crankshafts 40 are rotated around the central axis in the same direction at the same rotational speed.

  At this time, the eccentric portion 44 of the crankshaft 40 eccentrically rotates in the crank hole 37 of the pinion 22 to rotate the pinion 22 eccentrically, and the number of teeth of the external teeth 23 of the pinion 22 is the pin teeth 21 of the case 14. Therefore, the carrier 16 is greatly decelerated by the eccentric oscillating rotation of the pinion 22 and rotated at a low speed, and the distal arm 17 is rotated (oscillated) around the base end portion.

  Here, as described above, the support shaft 59 supported by the carrier 16 supports the two-stage gears, that is, the large-diameter gear 65 and the small-diameter gear 66 of the third external gear 63, while the shaft of the crankshaft 40 is supported. Since only one stage of the second external gear 58 meshing with the small-diameter gear 66 is attached to one side end (one side end) in the direction, the axial length of the entire reduction gear can be shortened and the size can be reduced. Become.

  In addition, until the driving force is transmitted from the first external gear 54 to the crankshaft 40, there are two gears, that is, the large external gear 65 of the first external gear 54 and the third external gear 63, and the third external gear 63. Since only the small-diameter gear 66 and the second external gear 58 mesh with each other, noise can be reduced and energy loss can be reduced. Further, since only one type of the third external gear 63 has the large diameter gear 65 and the small diameter gear 66, the structure can be simplified.

Embodiment 2 of the present invention will be described below with reference to the drawings.
4, 5 and 6 are views showing Embodiment 2 of the present invention. In this embodiment, the motor 48 is attached to the end plate portion 28 of the carrier 16 by a plurality of bolts 49, and at the tip (the other end side) of the output shaft 55 extending from the motor 48 toward the other side in the axial direction. A first external gear 54 is provided, and a second external gear 58 is attached to one axial end (the other axial end) of the crankshaft 40 of the eccentric oscillating speed reducer 13.

  Further, in this embodiment, similarly to the above embodiment, the carrier 16 is loosely fitted into the end plate portions 28 and 29 and the through hole 72 formed integrally with the end plate portion 28 and formed in the pinion 22. 73 and at least two members, here, three members. Among these, a plurality of fastening members (the column member 73 and the end plate portion 29 are screwed toward one side in the axial direction ( The bolts 74 of the same number as the column portions 73) are fastened and fastened together. The column portion 73 and the end plate portion 29 are usually fastened by bolts and pins other than the bolt 74 as the fastening member described above.

  These bolts 74 constitute a support shaft 76. On the outside of these support shafts 76 (bolts 74), there are a large-diameter gear 65 located on the other side in the axial direction and a small-diameter gear 66 located on one side in the axial direction. A third external gear 63 is supported rotatably through a cylindrical intermediate member 75 and a bearing 64, and the large-diameter gear 65 is connected to one first external gear 54 as described above. The small diameter gear 66 meshes with the second external gear 58, respectively. The intermediate member 75 and the bearing 64 described above can be omitted, but in this case, it is preferable to integrally form a bearing metal or the like on the outer periphery of the bolt 74 supporting the third external gear 63. .

  As described above, when the carrier 16 is composed of two or more members (end plate portions 28 and 29, column portion 73), the support shaft 76 (bolt 74) supports the third external gear 63 rotatably. If the column portion 73 and the end plate portion 29 are fastened, the support shaft 76 can be shared for both the fastening of the carrier 16 and the support of the third external gear 63, thereby simplifying the structure. Therefore, the production cost can be reduced. Other configurations and operations are the same as those in the first embodiment.

    In the embodiment described above, the second external gear 58 is attached to all (three) crankshafts 40, and the third external gear 63 is attached to the same number (three) of support shafts 59 as the crankshaft 40. The large-diameter gears 65 of the three third external gears 63 are meshed with the single first external gear 54, while the small-diameter gears 66 of the three third external gears 63 are associated with the corresponding second external gears 58. In this invention, the second external gear is attached to only one of the crankshafts, and is installed between the crankshaft and the crankshaft adjacent to the crankshaft. One third external gear is supported by only one support shaft, the large-diameter gear of the third external gear is supported on the first external gear, and the small-diameter gear of the third external gear is 1: 1 on the second external gear. May be engaged with each other. At this time, the motor may be arranged at a predetermined distance in the radial direction from the central axis of the eccentric oscillating speed reducer.

  In the above-described embodiment, the other side portion of the support shaft 59 in the axial direction is fixed to the carrier 16 (end plate portion 28), and the third side of the support shaft 59 is fixed to the one side portion in the axial direction via the bearing 64. Although the external gear 63 is rotatably supported, in the present invention, the support shaft is rotatably supported by the carrier via the bearing, while the third external gear is fixed to the support shaft. In any case, the third external gear can be rotated. Furthermore, in the above-described embodiment, the support shaft 59 is supported by the carrier 16 (end plate portion 28). However, in the present invention, the second member of the industrial robot that is integrally connected to the carrier. You may make it support on (tip side arm). In the above-described embodiment, the support shaft 59 is supported by the carrier 16 (the end plate portion 28 or 29) so as to protrude toward the arm (the front end side arm 17 or the base end side arm 11). In the invention, the support shaft may be supported by the carrier (end plate portion) so as to protrude to the pinion side.

  In the above-described embodiment, the difference in the number of teeth between the pin teeth 21 of the eccentric oscillating speed reducer 13 and the number of external teeth 23 of the pinion 22 is 1, but in the present invention it is 2 or more. May be. Further, in the above-described embodiment, the case 14 which is the fixed portion of the eccentric oscillating speed reducer 13 is attached to the proximal end arm 11 which is the first member of the industrial robot 12, and the second member of the industrial robot 12 is attached. Although the carrier 16 as the rotating part is attached to the distal arm 17 as the first part, the carrier as the fixing part of the eccentric oscillating speed reducer is attached to the first member of the industrial robot as the second member. You may make it attach the case which is a rotation part to.

  The present invention can be applied to a turning part structure of an industrial robot using an eccentric oscillating speed reducer.

It is front sectional drawing which shows Example 1 of this invention. It is the II arrow directional view of FIG. It is explanatory drawing which shows the transmission path | route of a driving force. It is front sectional drawing which shows Example 2 of this invention. It is the II-II arrow line view of FIG. It is explanatory drawing which shows the transmission path | route of a driving force.

Explanation of symbols

13 ... Eccentric oscillation type reducer 16 ... Carrier
40 ... Crankshaft 48 ... Motor
54 ... 1st external gear 58 ... 2nd external gear
59 ... support shaft 63 ... third external gear
65 ... Large gear 66 ... Small gear
74 ... Fastening member 75 ... Intermediate member
76 ... Support shaft

Claims (1)

    An eccentric oscillating speed reducer having a plurality of crankshafts that are rotatably supported by the carrier at both ends in the axial direction and spaced equidistantly in the circumferential direction, and a first external gear that is rotated by a driving force transmitted from the motor, A second external gear attached to one end in the axial direction of at least one crankshaft, a support shaft supported by the carrier, supported by the support shaft, meshed with the first external gear, and A large-diameter gear having a larger diameter than one external gear, and a rotatable third external gear that meshes with the second external gear and has a small-diameter gear that is smaller in diameter than the second external gear. To reduce the speed.

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