JP4925992B2 - Eccentric differential reducer and swivel structure using the eccentric differential reducer - Google Patents

Description

    The present invention relates to an eccentric differential type reduction gear and a turning portion structure in an industrial machine such as a turning drum, an arm joint, or a machine tool of an industrial robot using the eccentric differential type reduction gear.

As conventional eccentric differential reducers, for example, those described in Patent Documents 1, 2, and 3 are known.
JP-A-7-108485 JP-A-7-124883 Japanese Utility Model Publication No. 64-38352

    Here, the thing of patent document 1 is arrange | positioned between a fixing | fixed part and a rotation part, has a hollow hole in the center part, has two or more crankpins, and was given to this crankpin An eccentric differential reduction gear that decelerates and transmits the rotational driving force to the rotating part to rotate the rotating part, a drive motor attached to the rotating part, and a first external gear fixed to the output shaft of the drive motor; The second external gear that is rotatably supported by the speed reducer while maintaining a coaxial relationship with the hollow hole, and is arranged axially away from the second external gear and the second external gear that directly meshes with the first external gear. A cylindrical body that has a third external gear and rotates by receiving a rotational driving force from the first external gear, and is fixed to each crank pin in a state of being directly meshed with the third external gear, and the rotation of the cylindrical body A fourth external gear for transmitting the driving force to each crank pin; It includes those were.

  Further, the one of Patent Document 2 is arranged between a fixed part and a rotating part, has a hollow hole in the center part, and has two or more crank pins, and the rotation applied to the crank pins. An eccentric differential reduction gear that decelerates the driving force and transmits it to the rotating part to rotate the rotating part, a driving motor attached to the rotating part, a first external gear fixed to the output shaft of the driving motor, A cylindrical body having a second external gear and a third external gear, which are rotatably supported by the speed reducer while maintaining a coaxial relationship with the hollow hole, and are disposed apart from each other in the axial direction, and the first external gear And a fourth external gear that meshes directly with both the second external gear and the rotational drive force of the first external gear to the cylindrical body, and is fixed to each crankpin in a state of meshing directly with the third external gear, Transmits the rotational driving force of the cylinder to the crank pins. 5 and the external gear is one with a.

  Furthermore, the thing of patent document 3 is a substantially cylindrical internal gear which has many pins in an inner periphery, the external gear which has an external tooth which is accommodated in an internal gear and meshes with a pin, and an internal gear. A camshaft comprising: a rotatable support member; and two or more camshafts having opposite ends rotatably supported by the support member and having eccentric cams provided at a central portion inserted in external gears. The rotational driving force applied to is reduced and transmitted. In this case, a cylindrical input shaft having a spur gear fixed to a tip projecting from the cam shaft support member toward the axial direction and having a spur gear meshing with the spur gear radially inward of the spur gear. Is arranged.

    However, in the thing like patent document 1, since a 2nd external gear becomes a large diameter, there exists a problem that a big noise generate | occur | produces at the time of turning. The reason for this is that the distance between the output shaft of the drive motor and the center shaft of the speed reducer must be greater than a certain value for reasons such as avoiding interference between the drive motor and the wiring or piping that passes through the hollow hole. This is because the first external gear fixed to the output shaft of the drive motor must have a small diameter in response to a request for downsizing the entire apparatus, and the second external gear inevitably has a large diameter. In order to reduce the diameter of the second external gear, it has also been proposed that a fourth external gear as an idle gear be interposed between the first external gear and the second external gear as in Patent Document 2. However, in this case, in order to rotate the two crank pins synchronously, the first, second, third and fourth external gears and the two fifth external gears corresponding to the two crank pins, Six external gears are required. As a result, there is a problem that the structure is complicated and the manufacturing cost is high.

  The present invention provides an eccentric differential type speed reducer capable of effectively reducing noise during turning while having a simple structure and being inexpensive, and a turning part structure using the eccentric differential type speed reducer. With the goal.

Such an object is as follows. First, a substantially cylindrical case having a large number of pin teeth on the inner periphery, a pinion housed in the case and having external teeth meshing with the pin teeth, and the axial direction of the pinion One side flange disposed on one side, another side flange disposed on the other axial side of the pinion, and a plurality of connecting rods extending in the axial direction connecting the one side flange and the other side flange; A carrier that is rotatably supported by the case, and two or more crank parts provided at the center of the carrier that are rotatably supported by the carrier and inserted into the pinion. Each of the crank pins is further provided with a gear, and each of the crank pins is rotated in the same direction at the same rotational speed by meshing with each of the gears radially inward of the gear. In an eccentric differential speed reducer arranged a cylindrical gear that,
Two crank portions are provided at the center of each crank pin, and each gear is provided between the two crank portions, while being fixed to the carrier radially inward of the cylindrical gear and the pinion . By providing a cylindrical body, a hollow hole is formed in the central portion of the eccentric differential reduction gear, the cylindrical gear is supported by the carrier via a bearing, and each gear and the cylindrical shape are further supported. A meshing portion with a gear is sandwiched between the one side flange and the other side flange, and is disposed in a radially inner space of each connecting rod , and the entire cylindrical body and the entire cylindrical gear Can be achieved by an eccentric differential reducer arranged both within the axial width of the carrier ,
2ndly, in the turning part structure provided with the reduction gear arrange | positioned between a fixing | fixed part and a rotation part, and the drive motor which transmits rotational drive force to this reduction gear, the said reduction gear is an eccentric difference of Claim 1. This can be achieved by the swivel structure that is composed of a dynamic speed reducer.

  In the present invention, the structure is simple and the manufacturing cost is low. Furthermore, since the gear is provided at the axially central portion of the crank pin supported at both ends, noise due to meshing with the cylindrical gear is reduced, and noise during turning can be effectively reduced.

  As the first and second transmission members, an external gear or a pulley around which a belt is stretched can be used.

Hereinafter, an eccentric differential reduction gear will be described with reference to the drawings.
1 and 2, reference numeral 11 denotes a main body (base) of an industrial robot as a fixed portion, and a space 12 in which wiring and piping are accommodated is formed in the main body 11. A swiveling body 13 serving as a rotating portion that rotates around a vertical axis is installed above the main body 11, and a hole 14 that extends vertically is formed on the rotating shaft of the swiveling body 13.

  Reference numeral 17 denotes an eccentric differential type speed reducer disposed between the main body 11 and the swivel body 13. The speed reducer 17 has a substantially cylindrical case 19 fixed to the upper end of the main body 11. On the inner periphery of the case 19, a large number of cylindrical pin teeth 20 are provided in a state where only half are embedded in the central portion in the axial direction. These pin teeth 20 extend in the axial direction and are spaced equidistantly in the circumferential direction. Reference numeral 21 denotes two disk-shaped pinions housed in the case 19, and a large-diameter through hole 22 is formed in the center of these pinions 21. Further, external teeth 23 having a smaller number of teeth than the pin teeth 20 of the case 19 are formed on the outer periphery of the pinions 21, and these external teeth 23 mesh with the pin teeth 20. 26 is a carrier disposed in the case 19, and this carrier 26 is disposed on one side flange 27 disposed on one side (lower side) of the pinion 21 and on the other side (upper side) of the pinion 21 in the axial direction. A plurality of axially extending flanges disposed on and fixed to the revolving body 13 and having a lower end integrally connected to the first flange 27 and an upper end detachably connected to the other flange 28 The connecting rods 29 are loosely fitted into loose fitting holes 30 formed in the pinion 21. Reference numeral 32 denotes a pair of bearings interposed between the one and other flanges 27 and 28 and the case 19, and the carrier 26 is rotatably supported by the case 19 by these bearings 32. Further, seal members 33 are interposed between the one-side and other-side flanges 27 and 28 and both ends of the case 19 in the axial direction. Reference numeral 37 denotes two or more axially extending crankshafts arranged here at equal distances in the circumferential direction, here two crankpins. Each crankpin 37 has one axial end (lower end) on one side via a bearing 38. The other end of the flange 27 is rotatably supported by the other flange 28 via a bearing 39. Each crank pin 37 has two crank portions 40 that are eccentric at the center, and these crank portions 40 are inserted into through holes 41 formed in the pinion 21 with needle bearings 42 interposed therebetween. Yes. Reference numeral 43 denotes a cylindrical body. The cylindrical body 43 has one axial end portion (lower end portion) inserted and fixed in the one-side flange 27, and its axial central portion is loose in the through hole 22. Further, the other axial end portion (upper end portion) is loosely fitted in the hole 14 of the swivel body 13. Reference numeral 44 denotes a seal member interposed between the other axial end of the cylindrical body 43 and the swivel body 13. The case 19, the pinion 21, the carrier 26, the crank pin 37, and the cylindrical body 43 as a whole are arranged so that the rotational driving force applied to the crank pin 37 is decelerated and transmitted to the revolving body 13 so that the revolving body 13 is vertically The speed reducer 17 is configured to rotate around a certain axis, and the speed reducer 17 is provided with the cylindrical body 43 as described above, so that a hollow hole 45 communicating the inside of the revolving body 13 and the space 12 at the center. Is formed. The hollow hole 45 is used for passing cables, pipes, etc. here, such as cables 46.

  Reference numeral 50 denotes a drive motor (servo motor) attached to the swivel body 13, and an output shaft 51 of the drive motor 50 is arranged in the radial direction from the center of the hollow hole 45 in order to avoid interference with the cables 46. The predetermined distance is larger than the distance from the center of the hollow hole 45 to the rotating shaft of the crankpin 37. As a result, the crank pin 37 is positioned between the output shaft 51 of the drive motor 50 and the cylindrical body 43. An external gear 52 as a first transmission member is fixed to the tip of the output shaft 51, and the other axial end (upper end) of the crank pin 37 protruding from the carrier 26 of one particular crank pin 37a. An external gear 53 as a second transmission member is fixed, and the external gear 53 and the external gear 52 are directly meshed with each other. As a result, the rotational driving force of the external gear 52 is directly transmitted to the external gear 53 to first rotate the specific crank pin 37a. If the external gears 52 and 53 are directly meshed with each other in this way, the drive motor 50 can be arranged in a wide range around the crankpin 37a. A cylindrical gear 55 coaxial with the hollow hole 45 is disposed in the speed reducer 17, specifically between the external gear 53 and the cylindrical body 43, and one end (lower end) in the axial direction of the cylindrical gear 55 is The bearing 56 is rotatably supported on the other flange 28 of the speed reducer 17. Note that the other axial end portion (upper end portion) of the cylindrical gear 55 is rotatably supported by the swing body 13 via a bearing 57. The cylindrical gear 55 is directly meshed with the external gear 53. As a result, the cylindrical gear 55 is rotated by directly receiving the rotational driving force from the external gear 53. An external gear 58 that meshes directly with the cylindrical gear 55 is fixed to the other axial end (upper end) protruding from the carrier 26 of the crankpin 37b other than the specific crankpin 37a, and the external gear 58 is fixed to the cylindrical gear 55. The crank pin 37 b is rotated by directly receiving the rotational driving force from 55, and the rotational torque is distributed to the two crank pins 37. The drive motor 50 may be attached to the main body (fixed part) 11 or the fixed part of the case 19.

Next, the operation of such an eccentric differential type speed reducer will be described.
When the swivel body 13 is swung with respect to the main body 11, the drive motor 50 is operated to rotate the output shaft 51 and the external gear 52 integrally. At this time, since the external gear 53 is directly meshed with the external gear 52, the rotational drive force is directly received from the external gear 52, and the specific crank pin 37a is first rotated. As a result, the pinion 21 rotates eccentrically (revolves) at the same rotational speed as the crank pin 37a. At this time, the external teeth 23 of the pinion 21 are smaller in number of teeth than the pin teeth 20 of the case 19 and mesh with the pin teeth 20 of the case 19, and the case 19 is fixed to the main body 11 so that the case 19 cannot rotate. Therefore, the rotational driving force applied to the specific crank pin 37 a is decelerated at a high ratio by the case 19 and the pinion 20, taken out by the carrier 26, and transmitted to the revolving body 13. As a result, the revolving structure 13 rotates at a low speed and a large torque around the vertical axis. At this time, the rotational driving force from the external gear 53 is transmitted to the crank pins 37b other than the specific crank pin 37a via the cylindrical gear 55 and the external gear 58 that are directly meshed with each other. 37b also rotates in the same manner as the specific crank pin 37a. Here, since the external gear 53 fixed to the crankpin 37a is located between the external gear 52 (the output shaft 51 of the drive motor 50) and the cylindrical gear 55, these external gears 52 and 53 and the cylindrical gear Any of the gears 55 can have a small diameter, which can effectively reduce noise during turning. Moreover, in order to rotate the two crank pins 37a and 37b described above, the four gears of the external gears 52, 53 and 58 and the cylindrical gear 55 may be used. As a result, the structure is simplified and the manufacturing is possible. Cost is also low.

3 and 4 show the first embodiment of the present invention. In this embodiment, the pulley 60 is used as the first transmission member fixed to the output shaft 51 of the drive motor 50, and the pulley 61 is also used as the second transmission member fixed to the specific crank pin 37a. The timing belt 62 is stretched over the belts 60 and 61 so that the rotational driving force is directly transmitted from the pulleys 60 to 61. In this embodiment, an intermediate gear 63 is provided between the two crank portions 40 in the axial center of a specific crank pin 37a, and the pinion 21 and the intermediate gear 63 are entirely connected to the shaft of the carrier 26. Between the cylindrical body 43 disposed within the width in the direction , both ends are rotatably supported by the carrier 26 via the bearings 64, and the cylindrical gear 65 disposed entirely within the axial width of the carrier 26 is provided. Provided. By directly meshing the intermediate gear 63 and the cylindrical gear 65, the rotational driving force of the pulley 61 is transmitted to the cylindrical gear 65 via a specific crank pin 37a and the intermediate gear 63. The cylindrical gear 65 is directly meshed with an external gear 66 provided at the center in the axial direction of the other crank pin 37b. As a result, the crank pin 37b has the same rotational speed in the same direction as the crank pin 37a. Rotate. Further, the meshing portion of the intermediate gear 63, the external gear 66 and the cylindrical gear 65 is sandwiched between the one side flange 27 and the other side flange 28, and in the space inside the radial direction of each connecting rod 29. It is arranged. Since the intermediate gear 63 is provided at the axial center of the crank pin 37a supported at both ends, noise due to meshing with the cylindrical gear 65 is reduced, and the rotational force of the crank pin 37a is reduced. Since it is merely transmitted to the crankpin 37b via the cylindrical gear 65 and the external gear 66, a narrow width is sufficient. In this embodiment, the pulleys 60 and 61, the intermediate gear 63, the cylindrical gear 65, and the five gears of the external gear 66 may be used to rotate the two crank pins 37a and 37b. As a result, the structure is simple and the production cost is low. Further, as described above, the cylindrical gear 65 is housed in the speed reducer 17, and the seal member 67 is provided between the crank pin 37 and the other flange 28, so that the oil and grease in the speed reducer 17 are sealed. Accordingly, the pulleys 60 and 61 can be used as the first and second transmission members. Other configurations and operations are the same as those of the above-described eccentric differential reduction gear.

  The present invention can be applied to the industrial field of an eccentric differential type speed reducer and a swivel structure using the same.

It is a front sectional view showing an example of an eccentric differential type reduction gear. It is II sectional view taken on the line of FIG. It is front sectional drawing which shows Example 1 of this invention. It is II-II arrow sectional drawing of FIG.

11 ... Fixed part 13 ... Rotating part
17… Eccentric differential reducer 37… Crank pin
37a ... Specific crank pin 45 ... Hollow hole
50 ... Drive motor 51 ... Output shaft
52 ... 1st transmission member 53 ... 2nd transmission member
55 ... Cylindrical gear 58 ... External gear

Claims (3)

A substantially cylindrical case having a large number of pin teeth on the inner periphery, a pinion housed in the case and having external teeth meshing with the pin teeth, and a one side flange disposed on one side in the axial direction of the pinion; The other side flange disposed on the other side in the axial direction of the pinion, and a plurality of connecting rods extending in the axial direction for connecting the one side flange and the other side flange, and is rotatable to the case Each of the crank pins includes a supported carrier, and two or more crank pins inserted into the pinion, and a crank portion provided at a center portion of the carrier so that both ends thereof are rotatably supported by the carrier. In addition, gears are further provided on the inner side of each of the gears, and cylindrical gears are arranged in which the crank pins rotate in the same direction at the same rotational speed by meshing with the gears on the radially inner side of the gears. In the heart differential speed reducer,
Two crank portions are provided at the center of each crank pin, and each gear is provided between the two crank portions, while being fixed to the carrier radially inward of the cylindrical gear and the pinion . By providing a cylindrical body, a hollow hole is formed in the central portion of the eccentric differential reduction gear, the cylindrical gear is supported by the carrier via a bearing, and each gear and the cylindrical shape are further supported. A meshing portion with a gear is sandwiched between the one side flange and the other side flange, and is disposed in a radially inner space of each connecting rod , and the entire cylindrical body and the entire cylindrical gear An eccentric differential reducer characterized in that both are arranged within the axial width of the carrier .     The eccentric differential reduction gear according to claim 1, wherein the reduction gear is provided with a reduction gear disposed between the fixed portion and the rotation portion and a turning portion structure including a drive motor that transmits a rotational driving force to the reduction gear. The swivel part structure comprised from.     The swivel structure according to claim 2, wherein the drive motor is installed at a predetermined distance in the radial direction from the center of the hollow hole formed at the center of the eccentric differential reduction gear.

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