JP2010091041A - Eccentric oscillating gear transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eccentric oscillating gear transmission changing a motor position with slight layout change of a gear group. <P>SOLUTION: A transmission 100 is of a type in which an external gear meshed with an internal gear is eccentrically rotated. Input gears 22 are fixed to one end side of two crankshafts 14 for eccentrically rotating the external gear. An idle gear 24 meshed with two input gears 22 and meshed with a pinion gear 26 of a motor is supported by a carrier 8. The idle gear 24 is off-set from an axial line CL of the transmission 100. According to such a structure, the motor position can be radially changed from the axial line CL only by changing the position of the pinion gear 25 within a range S without changing the layout of the other gears. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an eccentric oscillating gear transmission in which any one of an internal gear and an external gear meshing with the internal gear rotates eccentrically with respect to the other gear.

  There is known an eccentric oscillating gear transmission that obtains a predetermined speed ratio by rotating one of an internal gear and an external gear meshing with the internal gear eccentrically with respect to the other gear. ing. The present specification mainly describes a gear transmission in which an external gear rotates eccentrically. Hereinafter, for the sake of simplicity, the “eccentric oscillating gear transmission” may be referred to as “eccentric oscillating transmission” and more simply “transmission”.

  In a transmission device in which the external gear rotates eccentrically, the external gear is supported by the carrier so as to be eccentrically rotatable. The carrier is rotatably supported coaxially on the internal gear. In this transmission, when the internal gear is fixed to another device, the carrier corresponds to the “output shaft” of the transmission. When the carrier is fixed to another device, the internal gear corresponds to the “output shaft”. For example, when the transmission device is applied to a robot joint, when the internal gear is fixed to the base arm of the robot, the carrier is fixed to the distal arm as an output shaft. Alternatively, when the carrier is fixed to the base side arm of the robot, the internal gear is fixed to the tip side arm as an output shaft. Whether the internal gear or the carrier is fixed to another device depends on the use of the transmission device. In the transmission device of the type in which the internal gear rotates eccentrically, the internal gear is supported by the carrier so that it can rotate eccentrically, and the carrier is supported by the external gear so that it can rotate coaxially. In a transmission device in which the internal gear rotates eccentrically, when one of the carrier and the external gear is fixed to the other device, the other corresponds to the “output shaft”.

  For example, Patent Document 1 discloses a transmission device in which an external gear rotates eccentrically. The transmission device has the following configuration. A plurality of crankshafts extending parallel to the carrier axis are supported by the carrier. An eccentric body is fixed to each crankshaft. The eccentric body is fitted in a fitting hole provided in the external gear. As the crankshaft rotates, the external gear engaged with the eccentric body rotates eccentrically. A center gear is arranged coaxially with the carrier, and an input gear fixed to each crankshaft meshes with the center gear. The center gear is also engaged with a pinion gear that transmits the torque of the motor to the crankshaft. The torque of the motor is evenly transmitted from the center gear to the plurality of input gears.

JP 2002-106650 A

  Even if the same transmission device is employed, the desired motor position varies depending on the application. Therefore, it is preferable that the transmission device can change the position of the motor by changing the layout with few gear groups. In the conventional transmission device, the motor position in the axial direction of the transmission device and the motor position along the circumferential direction of the transmission device axis can be easily changed. However, the motor position in the radial direction of the axis of the transmission cannot be easily changed. When changing the motor position in the radial direction, it is necessary to add gears and change the layout of a plurality of gears, such as adding a new idle gear. This specification discloses the transmission which can change the motor position in the radial direction of a transmission with the layout change with few gear groups.

  The transmission device disclosed in this specification is an eccentric oscillating type in which one of an internal gear and an external gear meshing with the internal gear rotates eccentrically with respect to the other gear. This transmission device has a carrier, two crankshafts, and an idle gear. The carrier is rotatably supported coaxially by the other gear (a gear that does not rotate eccentrically) of the internal gear and the external gear. The two crankshafts rotatably supported by the carrier extend parallel to the carrier axis. The two crankshafts are arranged at equidistant positions in the radial direction from the carrier axis. The two crankshafts are fixed with an input gear to which the torque of the motor is transmitted, and an eccentric body that engages with one of the internal gear and the external gear to rotate the gear eccentrically. The idle gear meshes with the input gears of the two crankshafts and meshes with a pinion gear that transmits the torque of the motor to the crankshaft. The idle gear axis is offset radially from the carrier axis.

  In this transmission, the axis of the idle gear that uniformly transmits the torque of the motor to the crankshaft is offset from the axis of the carrier (that is, the axis of the transmission). Therefore, the distance between the pinion gear axis and the carrier axis can be changed by changing the position of the pinion gear along the circumferential direction of the idle gear. The “distance between the pinion gear axis and the carrier axis” may be referred to as “the radial position of the pinion gear”. Most simply, the pinion gear is attached to the motor shaft. In that case, being able to change the radial position of the pinion gear means that the motor position can be changed. This transmission device can change the position of the motor only by changing the layout of the pinion gear (the radial position of the pinion gear) without changing the layout of the other gears.

  The number of crankshafts may be any number, but the number of crankshafts having two input gears to which the motor torque is transmitted is two. This is because when there are three or more crankshafts equipped with the input gear, the idle gear meshing with the three or more input gears must be arranged coaxially with the carrier. The transmission device disclosed in the present specification allows the idle gear to be arranged at a position offset from the carrier axis by limiting the number of the crankshafts having the input gears to two.

  In the transmission device disclosed in the present specification, it is preferable that the axis of the pinion gear is offset from a straight line passing through the axis of the carrier and the axis of the idle gear. The position of the pinion gear (that is, the position of the motor) can be brought close to the axis of the transmission.

  In the transmission device disclosed in the present specification, it is also preferable that the two crankshafts are arranged with the carrier axis interposed therebetween, and the axes of the two crankshafts and the carrier are aligned on a straight line. By arranging one crankshaft on both sides of the carrier axis, the balance of torque transmission to the external gear can be improved.

  The gear transmission disclosed in this specification can change the motor position in the radial direction of the transmission with a small layout change of the gear group.

  The characteristics of the transmission device 100 of the embodiment will be outlined. The transmission device 100 is an eccentric oscillating gear transmission in which an external gear 10 meshed with the internal gear 6 rotates eccentrically. The transmission device 100 includes a carrier 8, two crankshafts 14, and an idle gear 24. The carrier 8 is supported by the internal gear 6 so as to be rotatable coaxially. Each crankshaft 14 is rotatably supported by the carrier 8. The two crankshafts 14 are arranged with the axis line CL of the transmission 100 interposed therebetween, and the two crankshafts 14 and the axis line CL are aligned on a straight line. Each crankshaft 14 fixes an eccentric body 20 and an input gear 22. The eccentric body 20 is engaged with a through hole formed in the external gear 10 and rotates the external gear 10 eccentrically. The idle gear 24 meshes with the two input gears 22 and meshes with a pinion gear 26 that transmits the torque of the motor 28 to the crankshaft 14. The pinion gear 26 is fixed to the rotating shaft of the motor. The axis of the idle gear 24 is offset in the radial direction from the axis CL of the carrier 8. Further, the pinion gear 26 is offset from a straight line connecting the axis line CL of the carrier 8 and the axis line of the idle gear 24.

  A transmission device 100 (eccentric oscillation type gear transmission) according to an embodiment will be described with reference to the drawings. This transmission device 100 is applied to a solar power generation device, and rotates a horizontal beam 80 supporting a solar battery panel around a vertical column.

  FIG. 1 is a cross-sectional view of the transmission device 100 along the axis CL. FIG. 2 is a cross-sectional view of the transmission device 100 when viewed along line II-II in FIG. 3 is a cross-sectional view of the transmission device 100 when viewed along line III-III in FIG. 4 is a cross-sectional view of the transmission device 100 when viewed along line IV-IV in FIG. FIG. 1 is a cross-sectional view taken along line II in FIG. FIG. 4 shows only a part of the cross section.

  The gear transmission 100 includes a case 2 in which a plurality of internal teeth pins 4 are arranged on the inner periphery, a carrier 8, and two external gears 10. The plurality of internal teeth pins 4 are arranged at equal intervals along the inner periphery of the case 2 with the axis of the pins parallel to the axis CL of the transmission device 100. The case 2 and the plurality of internal teeth pins 4 constitute an internal gear 6. That is, the plurality of internal teeth pins 4 correspond to the internal teeth of the internal gear 6. The two external gears 10 are supported by the carrier 8 via a crankshaft 14 which will be described later, and mesh with the internal gear 6. The number of teeth of the internal gear 6 (the number of internal teeth pins 4) and the number of teeth of the external gear 10 are slightly different.

  The carrier 8 is rotatably supported by the case 2 (that is, the internal gear 6) via a pair of angular ball bearings 30. The carrier 8 is disposed coaxially with the internal gear 6, and its axis coincides with the axis CL of the transmission device 100. In the following description, the axis CL may be referred to as the axis of the carrier 8. The carrier 8 supports two crankshafts 14 so as to be rotatable. Each crankshaft 14 extends parallel to the axis CL and is supported by the carrier 8 via a pair of tapered roller bearings 16. As shown in FIGS. 2 and 3, the two crankshafts 14 are arranged with the axis line CL of the transmission device 100 interposed therebetween, and the axis line of the two crankshafts 14 and the axis line CL of the transmission device 100 are linear. Are lined up. In the center of the carrier 8, a central through hole 50 penetrating along the axis CL is provided.

  Two eccentric bodies 20 and one input gear 22 are fixed to each crankshaft 14. As shown in FIG. 3, the input gear 22 is splined to the crankshaft 14. Each of the two eccentric bodies 20 is engaged with a hole provided in each of the two external gears 10 via a needle roller bearing 18. The two external gears 10 rotate eccentrically around the axis CL while meshing with the internal gear 6 as the crankshaft 14 rotates.

  As shown in FIG. 1, the input gear 22 is fixed to one end of the crankshaft 14. In other words, the input gear 22 is located at one end of the carrier 8. Further, as shown in FIG. 3, the idle gear 24 meshes with the two input gears 22. Further, as shown in FIG. 4, the idle gear 24 is supported at one end of the shaft 23 press-fitted into the carrier 8 via a deep groove ball bearing 25. The input gear 22 and the idle gear 24 are external gears. As shown in FIG. 3, the idle gear 24 is also engaged with a pinion gear 26. The pinion gear 26 is fixed to the output shaft of the motor 28.

  When the radial movement of the idle gear 24 is restricted by the two input gears 22 and the pinion gear 26, that is, the axis of the pinion gear 26, the axis CL of the carrier 8, and the axis of the idle gear 24 are straight. When the pinion gears 26 are arranged so as to be aligned on a line, the structure shown in FIG. 5 may be adopted instead of the structure shown in FIG. FIG. 5 shows an alternative structure to that shown in FIG. In the structure shown in FIG. 5, thrust plates 225a and 225b are arranged on the respective sides of the idle gear 224 in the axial direction. The idle gear 224 is restricted from moving in the axial direction by the thrust plates 225a and 225b. The thrust plate 225 a is fitted in a recess provided in the horizontal beam 80 at a position facing one surface of the idle gear 224. The thrust plate 225 b is fitted in a recess provided in the carrier 8 at a position facing the other surface of the idle gear 224.

  The operation of the transmission device 100 will be described. The torque of the motor 28 is transmitted to the two input gears 22 (that is, the crankshaft 14) via the pinion gear 26 and the idle gear 24. Since the torque of the motor is transmitted from the one idle gear 24 to the two crankshafts 14, the torque of the motor is transmitted equally to the two crankshafts 14. When the two crankshafts 14 rotate, the eccentric gear 20 rotates eccentrically around the axis line CL while the external gear 10 meshes with the internal gear 6. The number of teeth of the external gear 10 and the number of teeth of the internal gear 6 are slightly different. When the eccentric body 20 rotates once, that is, when the axis of the external gear 10 moves around the axis CL, the external gear 10 The carrier 8 rotates by an angle corresponding to the difference in the number of teeth between the tooth gear 10 and the internal gear 6. One rotation of the crankshaft 14 is decelerated to an angle corresponding to the difference in the number of teeth between the external gear 10 and the internal gear 6. Note that the gear ratio between the pinion gear 26 and the input gear 22 does not depend on the number of teeth or the size of the idle gear 24. In other words, the idle gear 24 does not affect the gear ratio between the pinion gear 26 and the input gear 22.

  The case 2 (that is, the internal gear 6) is fixed to a column 92 of a solar power generation device 90 described later. A horizontal beam 80 that supports the solar cell panel is fixed to the carrier 8. The transmission device 100 and the motor 28 rotate the solar battery panel. That is, the carrier 8 corresponds to the output shaft of the transmission device 100.

  The advantages of the transmission device 100 will be described. As shown in FIG. 3, the idle gear 24 meshed with the pinion gear 26 and the two input gears 22 is disposed at a position offset in the radial direction from the axis CL of the carrier 8. On the other hand, the distance between the axis CL and the motor 28 is defined by the position of the pinion gear 26. Therefore, the mounting position of the motor 28 can be changed by changing the position of the pinion gear 26 along the circumference of the idle gear 24. Specifically, the distance between the axis CL and the motor 28 can be changed by changing the position of the pinion gear 26 within the range indicated by the symbol S in FIG. This transmission device 100 can change the mounting position of the motor without changing the layout of the gear group arranged downstream of the torque transmission path with respect to the idle gear 24. Here, “downstream of the torque transmission path” means downstream of the flow of torque transmitted from the motor to the carrier. The transmission device 100 can change the position of the motor along the radial direction of the transmission device 100 only by changing the layout of the pinion gears. The transmission device 100 can be applied to various devices with a slight layout change of the gear group.

  Further, as shown in FIG. 3, in the transmission device 100, the axis of the pinion gear 26 is offset from a straight line PL <b> 1 that connects the axis CL of the carrier 8 and the axis of the idle gear 24. With this configuration, the position of the motor 28 can be arranged at a position not far from the axis CL of the transmission device 100. The size (radial size) of the transmission device 100 including the motor can be reduced.

  With reference to FIG.1, FIG6 and FIG.7, the solar power generation device 90 provided with the transmission apparatus 100 is demonstrated. FIG. 6 shows a side view of the solar power generation device 90, and FIG. 7 shows a rear view of the solar power generation device 90. The case 2 of the transmission device 100 is fixed to the support column 92. The axis CL of the carrier 8 of the transmission device 100 extends along the vertical direction. A horizontal beam 80 is fixed to the carrier 8 of the transmission device 100. Solar cell panels 94 are fixed on both sides of the horizontal beam 80. The transmission device 100 rotates the horizontal beam 80 (that is, the solar cell panel 94) around the vertical axis.

  As described above, since the motor 28 is arranged offset from the axis CL of the transmission device 100, the solar power generation device 90 can bring the horizontal beam 80 closer to the axis CL of the transmission device 100. Thereby, the solar power generation device 90 can reduce the load moment which acts on the transmission device 100 due to the weight of the horizontal beam 80 including the solar battery panel 94.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. For example, the transmission device 100 according to the embodiment is a type in which the external gear 10 rotates eccentrically, but the present invention can also be applied to a transmission device in which the internal gear rotates eccentrically.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

Sectional drawing of a transmission is shown. Sectional drawing of the transmission device along the II-II line | wire of FIG. 1 is shown. Sectional drawing of the transmission device along the III-III line of FIG. 1 is shown. Sectional drawing of the transmission device along the IV-IV line of FIG. 3 is shown. 4 shows an alternative structure to that shown in FIG. The side view of the solar power generation device provided with the power transmission device is shown. The rear view of the solar power generation device provided with the transmission is shown.

Explanation of symbols

2: Case 4: Internal pin 6: Internal gear 8: Carrier 10: External gear 14: Crankshaft 20: Eccentric body 22: Input gear 24: Idle gear 26: Pinion gear 28: Motor 100: Transmission device

Claims (3)

An eccentric oscillating gear transmission in which any one of an internal gear and an external gear meshing with the internal gear rotates eccentrically with respect to the other gear,
A carrier rotatably supported coaxially on the other gear of the internal gear and the external gear;
An eccentric body that engages with one of the internal gear and the external gear to rotate eccentrically and the input gear are fixed, and two crankshafts that are rotatably supported by the carrier;
An idle gear that meshes with the input gear of the two crankshafts and meshes with a pinion gear that transmits the torque of the motor to the crankshaft;
An eccentric oscillating gear transmission characterized in that the axis of the idle gear is offset from the axis of the carrier.   2. The gear transmission according to claim 1, wherein an axis of the pinion gear is offset from a straight line passing through the axis of the carrier and the axis of the idle gear.   3. The gear according to claim 1, wherein two crankshafts are arranged across the carrier axis, and the two crankshaft axes and the carrier axis are aligned in a straight line. Transmission device.

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