JP4372063B2 - Eccentric differential reducer - Google Patents

Description

    The present invention relates to an eccentric differential reduction gear having two or more crankshafts and rotating a pinion eccentrically by rotating the crankshaft.

    As conventional eccentric differential reducers, for example, those shown in FIGS. 4 and 5 are known. This is a rotating case 14 provided with a large number of teeth 13 on the inner periphery, and is provided in the rotating case 14 with a slightly smaller number of teeth than the teeth 13 of the rotating case 14 on the outer periphery, and on the teeth 13 of the rotating case 14. A pinion 16 provided with meshing external teeth 15, two or more crankshafts 19 having a crank portion 18 inserted into the pinion 16, a carrier 17 for rotatably supporting the crankshaft 19, an external gear 21 on the outer periphery, And an external gear 25 fixed to one end of the output shaft 24 of the drive motor 26 meshes with the external gear 22, and the external gear 21 is the other end of each crankshaft 19. Is engaged with the two external gears 23 fixed to each other.

However, in such a conventional eccentric differential speed reducer, it is to be transmitted to the crank shaft 19 the rotation of the drive motor 26 via the external gear 25,22,21,23.

This invention aims at providing an eccentric differential speed reducer capable of a manufacturing operation costs and low cost.

The purpose of this is to provide a rotating case with a large number of teeth on the inner periphery and external teeth that are provided in the outer case and have slightly fewer teeth than the teeth of the rotating case and mesh with the teeth of the rotating case. In an eccentric differential reduction gear comprising: a pinion arranged in the circumferential direction, two or more crankshafts arranged equidistantly in the circumferential direction and having a crank portion inserted into the pinion, and a carrier that rotatably supports the crankshaft The rotation of the output shaft of the drive motor is transmitted to one of the two or more crankshafts and rotated, and the remaining crankshaft is rotated in synchronization with the one crankshaft. Can be achieved.

According to this eccentric differential reduction gear, the rotation of the output shaft of the drive motor is transmitted to any one of the two or more crankshafts and rotated, and the remaining crankshaft is moved to the one crankshaft. since then pivot in synchronism with a crankshaft, a manufacturing operation costs can be less expensive.

  According to a second aspect of the present invention, a drive motor is disposed on any one of the two or more crankshafts, and the one crankshaft and the output shaft of the drive motor are connected to each other. If it is directly connected and the driving force from the drive motor is directly applied to the crankshaft without going through the gears, backlash and noise based on the meshing of the gears will not occur, thereby rotating with low noise. The case can be decelerated and rotated with high accuracy. In addition, as described above, the gears are omitted and the output shaft of the drive motor and the crankshaft are directly connected, so that the manufacturing cost can be reduced.

Embodiments of the present invention will be described below with reference to the drawings.
In FIGS. 1, 2, and 3, reference numeral 29 denotes a flange member (not shown) fixed to an apparatus body such as an industrial robot body or an index device. In the hole (passage) provided near the center of the flange member 29, Cylindrical bodies 32 and 33 are inserted and fixed. These cylinders 32 and 33 have holes 32a and 33a in the vicinity of the center, and these holes 32a and 33a are used as passages 30 through which piping and wiring are passed. The flange member 29 and the cylinders 32 and 33 described above constitute a fixing member 31 having a passage near the center as a whole.

A rotating case 36 that is cylindrical and coaxial with the fixing member 31 is loosely fitted on the outer side of the fixing member 31, and a plurality of pin teeth that are cylindrical in the axially central portion of the inner periphery of the rotating case 36. 37 is provided with almost half buried. These pin teeth 37 extend in the axial direction and are spaced equidistantly in the circumferential direction. Reference numeral 39 denotes two disk-shaped pinions, and a through hole 40 having a diameter larger than that of the cylindrical body 32 is formed at the center of these pinions 39. These pinions 39 are provided between the fixing member 31 and the rotating case 36 in a state where the cylindrical body 32 is loosely fitted in the through hole 40. Further, external teeth 41 having a slightly smaller number of teeth than the pin teeth 37 of the rotating case 36 are formed on the outer periphery of these pinions 39, and these external teeth 41 are composed of cycloid teeth, and all the teeth are connected to the pin teeth 37. Are engaged. 44 is a carrier provided between the fixing member 31 and the rotating case 36 and attached to the fixing member 31, and this carrier 44 is composed of a one-side flange 45 disposed on one side in the axial direction of the pinion 39, and a pinion 39. The other side flange 46 arranged on the other side in the axial direction, and a plurality of connecting rods 47 extending in the axial direction loosely fitted in the pinion 39 and connecting these one side, the other side flanges 45, 46 to each other, It is composed of One end portion of the cylindrical body 32 is attached to one side flange 45 of the carrier 44, and a flange member 29 is attached to the other side flange. Reference numeral 49 denotes a pair of bearings interposed between the one-side and other-side flanges 45 and 46 and the rotary case 36, and these bearings 49 enable the carrier 44 and the rotary case 36 to be relatively rotated. Reference numeral 50 denotes two or more, in this case, two crankshafts that are arranged at equal distances in the circumferential direction, and here are two crankshafts. One end of each crankshaft 50 is connected to one flange 45 via a bearing 51, The end is rotatably supported by the other flange 46 via the bearing 52. Each crankshaft 50 has two crank portions 53 eccentric to the center, and each crank portion 53 is inserted into a through hole 54 formed in the pinion 39 with a needle bearing 55 interposed therebetween. Yes. The rotating case 36, the pinion 39, the carrier 44, and the crankshaft 50 described above constitute an eccentric differential reducer 56 that can decelerate the input rotation at a high ratio.

58 is disposed outside the fixing member 31 on the other side of the other flange 46, more specifically, one drive motor (servo motor) fixed to the outer periphery of the cylindrical body 33. The output shaft 59 of the drive motor 58 is one end is directly connected to the other end of Tei displacement or single crankshaft 50a via a joint 60. As a result, when the driving motor 58 is operated and a driving force is directly applied from the output shaft 59 to the crankshaft 50a, the crankshaft 50a rotates and the pinion 39 rotates eccentrically (revolves). 61 is disposed outside the fixing member 31 on the other side of the other flange 46, more specifically, is fixed to the outer periphery of the cylindrical body 33, and overlaps with the drive motor 58 (the axial position coincides and is arranged in parallel). The encoder 61 is disposed 180 degrees away from the drive motor 58, and the detection shaft 62 has a joint 63 at one of the remaining crankshafts 50, that is, the other end of the crankshaft 50b. Are connected through. The encoder 61 detects the amount of rotation of the crankshaft 50 that rotates in synchronization, and controls the drive motor 58 based on the detection result. 65 is a bottomed cylindrical cover that is connected to the flange member 29 and the other end of the cylinder 33 and covers the drive motor 58 and the encoder 61, and 66 is between the rotating case 36 and the one-side flange 45 and rotates. Oil seals interposed between the case 36 and the flange member 29, respectively.

Next, the operation of the embodiment of the present invention will be described.
Now, the drive motor 58 is actuated and the rotation of the output shaft 59 is transmitted to the crankshaft 50a. As a result, the pinion 39 rotates eccentrically (revolves) at the same rotational speed as the crankshaft 50a. Suppose that they are rotating at the same rotation speed. At this time, the number of teeth 41 of the pinion 39 is slightly smaller than that of the pin teeth 37 of the rotating case 36 and is engaged with all the pin teeth 37 of the rotating case 36 so that the carrier 44 cannot rotate. Since it is fixed to the fixing member 31, the rotation of the drive motor 58 is decelerated to a high ratio and taken out from the rotating case 36 .

  Here, as described above, the output shaft 59 of the drive motor 58 is directly connected to the crankshaft 50a, and the driving force from the drive motor 58 is directly applied to the crankshaft 50a without using a gear as in the prior art. Therefore, there is no backlash or noise due to the meshing of the gears, and the rotating case 36 can be rotated at a reduced speed with high accuracy while reducing noise. Moreover, as described above, by omitting the gears and directly connecting the output shaft 59 of the drive motor 58 and the crankshaft 50a, the drive motor 58 is brought close to the crankshaft 50a and the encoder 61 is separated from the drive motor 58. Since it is connected to another crankshaft 50b distant from the drive motor 58, the drive motor 58 and the encoder 61 are arranged so as to overlap each other (a side-by-side arrangement in which the axial positions are matched). As a result, the axial length of the entire apparatus can be drastically shortened. Further, as described above, the encoder 61 is disposed apart from the drive motor 58 that generates heat, thereby reducing the thermal influence from the drive motor 58 on the encoder 61 and preventing the detection accuracy of the encoder 61 from being lowered. Further, since the gear is omitted as described above, the manufacturing cost can be reduced.

  The present invention can be applied to an eccentric differential reduction gear.

It is front sectional drawing which shows one Example of this invention. It is II sectional view taken on the line of FIG. It is a front sectional view explaining the outline. It is front sectional drawing which shows the outline | summary of the conventional eccentric differential reduction gear. It is sectional drawing similar to the FIG.

31 ... Fixing member 36 ... Rotating case
37 ... Teeth 39 ... Pinion
41 ... external teeth 44 ... carrier
50 ... Crankshaft 53 ... Crank part
58 ... Drive motor 59 ... Output shaft

Claims (2)

A rotating case a large number of teeth on the inner periphery are provided, disposed in the rotating case, a pinion external teeth provided to teeth than teeth of the rotating case to the outer circumference meshes with the teeth of slightly less and the rotary case, the circumferential An output shaft of a drive motor in an eccentric differential reduction gear including two or more crankshafts arranged equidistantly in a direction and having a crank portion inserted in a pinion, and a carrier that rotatably supports the crankshaft The rotation of the crankshaft is transmitted to any one of the two or more crankshafts and rotated, and the remaining crankshaft is rotated in synchronization with the one crankshaft. Eccentric differential reducer.     The eccentric differential reduction gear according to claim 1, wherein a drive motor is arranged on a rotation axis of any one of the crankshafts, and the one crankshaft and an output shaft of the drive motor are directly connected.

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