JP6573777B2 - External gear, eccentric oscillating gear device, robot, and method of using eccentric oscillating gear device - Google Patents

Description

  The present invention includes an external gear used in an eccentric oscillating gear device, a robot having an eccentric oscillating gear device, a method of using the eccentric oscillating gear device, and a plurality of eccentric oscillating gear devices. The present invention relates to a gear device group.

  For example, as disclosed in Patent Document 1, an eccentric oscillating gear device is known. The eccentric oscillating gear device includes a crankshaft having an eccentric body, an external gear through which the crankshaft passes, a carrier that holds the crankshaft and the external gear, and a case that holds the carrier. ing. In this eccentric oscillating gear device, when rotation is input from the driving device to the crankshaft, the external gear is driven by the eccentric rotation of the eccentric body, and moves, that is, oscillates on the circumference around the central axis. . At this time, the external teeth of the external gear mesh with the internal teeth of the case, so that the external gear swings and rotates with respect to the case. As a result, the rotation input to the crankshaft is output as the rotation of the other of the carrier and the case by fixing one of the carrier and the case. During operation of such a gear device, particularly when used as a speed reducer, a large load is applied to the external gear.

JP 2014-190451 A

  By the way, depending on the application of the gear device, a load applied to the external gear during one of the rotation operations in one direction and the rotation in the other direction may be reduced during the other rotation operation. In many cases, the tendency to become larger than the load applied to the toothed gear constantly occurs. Specifically, a device that lifts an arm by rotation in one direction and lowers an arm by rotation in another direction, such as a robot, or tightens a fastener by rotation in one direction and loosens the fastener by rotation in another direction. Such a tendency occurs when an eccentric oscillating gear device is applied to the device. A change in the magnitude of the load applied to the external teeth depending on the rotation direction causes generation of a local large stress at a specific position of the external gear, for example, one tooth surface of the external teeth. When a large stress is generated locally at a specific position of the external gear, it is necessary to set the life after considering the stress, so the set life is shorter than when no stress is generated locally. End up.

  The present invention focuses on the above points and aims to extend the life of the external gear.

The external gear of the first eccentric oscillating gear device according to the present invention is:
A plurality of external teeth provided around the central axis,
A plurality of insertion holes through which the crankshaft passes are formed on the circumference centered on the central axis,
It is formed asymmetrically around an axis passing through the center of two insertion holes adjacent along the circumference and the central axis.

  In the external gear of the first eccentric oscillating gear device according to the present invention, a through hole is formed between the two insertion holes, and the through hole is arranged from the center of the two insertion holes to the circumference. May be displaced along.

  In the external gear of the first eccentric oscillating gear device according to the present invention, a through hole is formed between the two insertion holes, and is positioned on one side along the circumference of the two insertion holes. The width of the frame portion positioned between the insertion hole and the through hole is located between the insertion hole positioned on the other side along the circumference of the two insertion holes and the through hole. It may be thicker than the width of the frame.

  In the external gear of the first eccentric oscillating gear device according to the present invention, the thickness of the external gear is asymmetric with respect to the axis passing through the center of the two insertion holes and the central axis. You may make it have.

  In the external gear of the first eccentric oscillating gear device according to the present invention, a reinforcing part is formed between the two insertion holes, and the reinforcing part is an insertion hole located on the other side along the circumference. It may be closer to the insertion hole located on one side along the circumference.

  The external gear of the second eccentric oscillating gear device according to the present invention, when incorporated in the eccentric oscillating gear device, has rigidity against a force applied when rotating in one direction and in the other direction. The external gear has different rigidity with respect to the force applied when rotating.

  The eccentric oscillating gear device according to the present invention includes any one of the first and second external gears according to the present invention described above.

  An eccentric oscillating gear device according to the present invention further includes a case having internal teeth, a carrier supported by the case, and a crankshaft rotatably supported by the carrier and having an eccentric body, The external gear may engage with the eccentric body of the crankshaft and swing and rotate with respect to the case while meshing with the internal teeth.

The robot according to the present invention is
The eccentric oscillating gear device according to the present invention described above, and two arms connected via the eccentric oscillating gear device,
Rigidity of the external gear with respect to the force applied to the external gear when the external gear rotates relative to the case in one direction relative to the case having the internal teeth engaged with the external teeth of the external gear. Is stronger than the rigidity of the external gear against the force applied to the external gear when the external gear rotates in the other direction with respect to the case.

A method of using the eccentric oscillating gear device according to the present invention includes:
A method of using an eccentric oscillating gear device in the robot according to the present invention described above,
When the eccentric oscillating gear device operates to lift the other arm with respect to one of the two arms connected via the eccentric oscillating gear device, the external gear is In this method, an eccentric oscillating gear device is used so as to rotate relative to the case in the one direction.

The gear device group according to the present invention includes:
A first eccentric oscillating gear device having an external gear whose rigidity against a force applied when rotating in one direction is stronger than a rigidity applied to a force applied when rotating in the other direction;
A second eccentric oscillating gear device having an external gear whose rigidity with respect to the force applied when rotating in one direction is weaker than the rigidity with respect to the force applied when rotating in the other direction; Is provided.

  In the gear device group according to the present invention, the external gear of the first eccentric oscillating gear device and the external gear of the second eccentric oscillating gear device may be a corresponding eccentric oscillating gear device. It may be a gear having the same configuration incorporated with the front and back reversed.

  ADVANTAGE OF THE INVENTION According to this invention, durability of an external gear can be improved and damage to an external tooth can be prevented effectively. Thereby, the lifetime improvement of an external gear is realizable.

It is a figure for demonstrating one embodiment of this invention, Comprising: The figure which shows the eccentric rocking | fluctuation type gear apparatus which has an external gear in the cross section which passes the rotating shaft line. The top view which shows an example of the external gear incorporated in an eccentric rocking | fluctuation type gear apparatus. The top view which shows the other example of the external gear incorporated in an eccentric rocking | fluctuation type gear apparatus. The top view which shows the further another example of the external gear incorporated in an eccentric rocking | fluctuation type gear apparatus. Sectional drawing along the VV line | wire of FIG. The perspective view which shows the robot as an example of application of an eccentric rocking | fluctuation type gear apparatus.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an eccentric oscillating gear device. 2-5 is a figure which shows some specific examples of the external gear by this invention. FIG. 6 is a perspective view showing a robot as an application example of the eccentric oscillating gear device.

As shown in FIG. 1, the eccentric rocking gear device 10 includes a case 15, a carrier 20, a crankshaft 25, and two external gears 30a and 30b. The case 15 has internal teeth 16. The crankshaft 25 drives the two external gears 30 a and 30 b and is supported by the carrier 20. In the eccentrically oscillating gear device 10, the external gear 30a, the external teeth 39 of 30b is, by meshing with the internal teeth 16 of the case 15, the carrier 20 is, relative to the case 15 around the rotational axis _{a m} Rotate.

The carrier 20 includes a first plate 21 and a second plate 22 that are fixed to each other by a fastener. The first plate 21 has a column portion 21a. The 1st plate 21 is connected with the 2nd plate 22 via the pillar part 21a. A space for accommodating the external gears 30a and 30b is formed between the first plate 21 and the second plate 22 by the column portion 21a. The column part 21a has passed through the through-hole 35 mentioned later of the external gear 30a, 30b. Carrier 20 and the case 15, by a pair of angular ball bearings 12 are rotatably connected around a rotation axis a _m.

The carrier 20 is formed with a support hole 23 that penetrates the first and second plates 21 and 22. Support hole 23 is provided three spaced equidistant on about the rotation axis a _m circumference. A crankshaft 25 is rotatably supported in each of the three support holes 23 via first and second cylindrical roller bearings 13a and 13b. Note that the rotation axis a _c of the crankshaft 25 is parallel to the relative rotation axis a _m between the case 15 and the carrier 20. Hereinafter, a direction parallel to the relative rotational axis a _m between the case 15 and the carrier 20 is referred to as “axial direction d _a ”, and a direction orthogonal to the relative rotational axis a _m between the case 15 and the carrier 20 is referred to as “radial direction d”. _r ".

Crankshaft 25 has two eccentrics 26a arranged in the axial direction _{d a,} and 26b, the input gear 27, the. Each eccentric body 26a, 26b has a disk-shaped or columnar outer shape. Two eccentrics 26a, 26b center axis _a ca _{a, a cb} are symmetrically decentered about the rotational axis _{a c} of the crankshaft 25. Two external gears 30a, 30b are in the first and the space formed between the second plate 21, 22 of the carrier 20 are arranged in the axial direction _{d a.} Each external gear 30a, 30b is formed with an insertion hole 33 through which the crankshaft 25 passes. The insertion holes 33 of the external gears 30a and 30b accommodate the corresponding eccentric bodies 26a and 26b together with the third and fourth cylindrical roller bearings 13c and 13d. Three insertion holes 33 are provided in each of the external gears 30 a and 30 b corresponding to the three crankshafts 25. The number of teeth of the external gears 30a and 30b is smaller than the number of teeth of the internal teeth 16 of the case 15 (for example, only one is smaller). Further, the outer diameters of the external gears 30 a and 30 b are slightly smaller than the inner diameter of the internal teeth 16 of the case 15.

In eccentrically oscillating gear device 10 having the above configuration, when the torque from the driving device 5 such as a motor is transmitted to the input gear 27, the crankshaft 25 rotates about the rotation axis a _c. At this time, the first and second eccentric bodies 26a and 26b rotate eccentrically. Thus, external tooth gears 30a, 30b is moved around the relative rotation axis _{a m.} At this time, the external teeth 39 of the external gears 30 a and 30 b mesh with the internal teeth 16 of the case 15. As a result, the external gears 30a, 30b swings rotates with respect to the case 15, the external gear 30a via a crank shaft 25, the carrier 20 supporting the 30b also its central axis as a rotation axis _{a m,} Case Rotate with respect to 15.

  The eccentric oscillating gear device 10 can be used as a speed reducer in the revolving parts 2a, 2b, 2c (see FIG. 6) that form the revolving body and arm joints of the robot 1, and the revolving parts of various machine tools. In the example shown in FIG. 6, one of a proximal arm (base arm) 2ap, 2bp, 2cp and a distal arm (tip arm) 2ad, 2bd, 2cd connected in a pivotable manner. By fixing the case 15 of the eccentric oscillating gear device 10 to the other side and the carrier 20 of the eccentric oscillating gear device 10 to the other side, the distal arm 2ad is fixed with respect to the proximal arms 2ap, 2bp, 2cp. , 2bd, 2cd can be rotated with high torque, and the relative positions of the distal arms 2ad, 2bd, 2cd with respect to the proximal arms 2ap, 2bp, 2cp can be controlled with high accuracy.

  By the way, when the carrier 20 and the case 15 rotate relative to each other, the external gears 30 a and 30 b receive a load from the internal teeth 16 that mesh with the external teeth 39 around the external teeth 39. The external gears 30 a and 30 b also receive a load from the crankshaft 25 that passes through the insertion hole 33 around the insertion hole 33. In particular, in the eccentric oscillating gear device 10 used as a transmission, the load is relatively large. The load applied to the external gears 30a and 30b causes deformation of the external gears 30a and 30b and further causes damage to the external gears 30a and 30b. As described in the section of the prior art, in the application of the eccentric oscillating gear device 10, the external gear 30a, during the operation of one of the rotation in one direction and the rotation in the other direction. The load applied to 30b tends to be larger than the load applied to the external gears 30a and 30b during the other operation.

For example, in the first turning unit 2a of the robot 1 shown in FIG. 6, when the carrier 20 and the case 15 rotate relative to each other in one direction d _ax , the distal arm against the dead weight of the distal arm 2ad is detected. 2ad is lifted with respect to the proximal arm 2ap. On the other hand, when the carrier 20 and the case 15 are relatively rotated in the other direction d _ay, so down lowering the distal arm 2ad against proximal arm 2ap. In the second pivoting portion 2b of the robot 1, the carrier 20 and the case 15 are relatively rotated in one direction _{d bx,} lifting the distal arm 2bd, the carrier 20 and the case 15 are relatively rotated in the other direction _{d By,} Lower and lower the distal arm 2bd. Therefore, in the eccentric oscillating gear device 10 applied to the first swivel unit 2a and the second swivel unit 2b, when the carrier 20 and the case 15 rotate relative to each other in one direction d _ax , d _bx , the external gear 30a, the load applied to 30b, the carrier 20 and the case 15 is the other direction _{d ay,} larger than the load applied to the external gear 30a, 30b at the time of relative rotation _{d by.}

In addition, when a tool for fastening the fastener is attached to the tip of the robot 1, the carrier 20 and the case 15 are relatively rotated in one direction d _cx in the third turning portion 2c of the robot 1 so that the fastener is removed. Can be tightened. On the other hand, the fastener can be loosened by the relative rotation of the carrier 20 and the case 15 in the other direction _dcx . Therefore, in the eccentric oscillating gear device 10 applied to the third swivel unit 2c, the load applied to the external gears 30a and 30b when the case 15 and the carrier 20 relatively rotate in one direction d _cy is: When the case 15 and the carrier 20 are relatively rotated in the other direction d _cy , the load is larger than the load applied to the external gears 30a and 30b.

  Thus, a change in the load applied to the external gear in the rotation direction means that a large stress is concentrated on a specific position of the external gear, for example, one tooth surface of the external gear. To do. When a large stress is locally generated in the external gear, the life needs to be set in consideration of the stress, so that the set life is shortened as compared with a case where no stress is locally generated.

  Furthermore, in the application of the gear device 10, the time during which the carrier 20 and the case 15 are relatively rotated in one direction may be significantly longer than the time during which the carrier 20 and the case 15 are relatively rotated in the other direction. In this case, stress acts on a specific position of the external gear, for example, one tooth surface of the external tooth for a long time. Even in such an example, since it is necessary to set the life in consideration of the stress, the set life is shortened as compared with the case where no stress is generated for a long time.

Therefore, in the eccentric oscillating gear device 10 described here, the rigidity of the external gears 30a and 30b with respect to the external force applied when rotating relative to one direction d _ax , d _bx and d _cx and relative to the other direction. The rigidity of the external gears 30a and 30b with respect to the external force applied when rotating is different. That is, instead of simply improving the rigidity of the external gears 30a and 30b as a whole, the rigidity against a load causing unexpected damage, that is, a large stress generated in one rotation direction is improved. By improving the rigidity, the stress generated in the external gears 30a and 30b can be reduced. Accordingly, the external gears 30a and 30b have appropriate rigidity according to the application of the eccentric oscillating gear device 10 while avoiding a significant increase in weight of the external gears 30a and 30b and the eccentric oscillating gear device 10. Thus, the life of the external gears 30a and 30b is extended.

  Hereinafter, the external gears 30a and 30b will be described in detail. It should be noted that the first external gear 30a and the second external gear 30b differ only in phase by 180 ° when incorporated in the eccentric oscillating gear device 10 (the eccentric directions from the relative rotation axis am are reversed). Only) can be formed as the same gear. Accordingly, the description common to the first external gear 30a and the second external gear 30b will be described without distinguishing the first external gear 30a and the second external gear 30b by using the reference numeral “30”. .

  First, in the specific examples shown in FIGS. 2 to 5 described below, the external gear 30 has an annular main body 31 and external teeth 39 arranged along the periphery of the annular main body 31. doing. As described above, the external teeth 39 mesh with the internal teeth 16 of the case 15. Three annular holes 33 through which the crankshaft 25 is respectively inserted are formed in the annular main body 31 of the external gear 30. The three insertion holes 33 are arranged at equal intervals on a virtual circumference vl centered on the central axis ca of the external gear 30. The external gear 30 is formed asymmetrically about the axis A passing through the center cp and the center axis ca of the two insertion holes 33 adjacent along the virtual circumference vl in plan view. .

The central axis ca of the external gear 30 forms the center of arrangement of the external teeth 39. In a state where the external gear 30 is incorporated into the eccentrically oscillating gear device 10, the center axis ca is parallel relative rotational axis a _m between the case 15 and the carrier 20. However, the center axis ca of the external gear 30, the eccentric member 26a of the crank shaft 25, the eccentric amount of 26b only, is offset from the relative rotational axis _{a m.}

  First, a first specific example of the external gear 30 shown in FIG. 2 will be described. In the external gear 30 according to the first specific example, a through hole 35 is formed in the annular main body 31 of the external gear 30. The through hole 35 is a portion through which the column portion 21a of the carrier 20 passes (see FIG. 1). The through-hole 35 is usually provided in the carrier 20 adopting a configuration in which the first plate 21 and the second plate 22 are coupled via the column portion 21a. As shown in FIG. 2, the through hole 35 is formed at a position between the two insertion holes 33 (33 a and 33 b) adjacent to each other along the virtual circumference vl. In particular, in the first specific example shown in FIG. 2, a first through hole 35 a and a second through hole 35 b are formed between two adjacent insertion holes 33, respectively. The arrangement of the two through holes 35a and 35b is offset from the center cp of the two insertion holes 33 (33a and 33b) along the virtual circumference vl. That is, the two through holes 35a and 35b are closer to the other side insertion hole 33b located on the other side along the virtual circumference vl than the one side insertion hole 33a located on the one side along the virtual circumference vl. doing. However, in the annular main body 31 of the external gear 30, the configuration between any two insertion holes 33 adjacent to each other along the virtual circumference vl is the same. That is, the annular main body 31 of the external gear 30 is generally rotationally symmetric about its central axis ca, more specifically, three-fold symmetric.

As shown in FIG. 2, in the external gear 30 having such a configuration, the annular main body 31 has an insertion hole 33 along the virtual circumference vl rather than one side of the insertion hole 33 along the virtual circumference vl. On the other side, it has a large part. In other words, the width w _b of the other side frame portion 37b defined by one insertion hole 33 and the through hole 35 (35a) located on the other side of the insertion hole 33 along the virtual circumference vl is than the width w _a of the one side frame portion 37a defined by the through-hole 35 (35b) located on one side of the insertion hole 33 and the insertion hole 33 along the virtual circular vl, is wider.

The external gear 30 is fixed to the case 15 in a first direction (the opposite direction in FIG. 2) with one side along the virtual circumference vl as the front and the other side along the virtual circumference vl as the back. and rotated clockwise) d _x. At this time, the external gear 30 operates together with the carrier 20 via the crankshaft 25 located in the insertion hole 33. Therefore, the external gear 30 receives a reaction force in the direction opposite to the rotation direction from the crankshaft 25. That is, when the external gear 30 rotates in the first direction d _x , the region opposite the crankshaft 25 in the region located on the other side of the insertion hole 33 along the virtual circumference vl, that is, the other side frame portion 37b. You will receive power. On the other hand, the external gear 30 is in a second direction with respect to the fixed case 15 with the other side along the virtual circumference vl as the front and the one side along the virtual circumference vl as the rear (see FIG. When rotated in the clockwise direction) d _y in 2, the external gear 30, the reaction force from the crankshaft 25 region located on one side of the insertion hole 33 along the virtual circular vl, i.e. at a side frame portion 37a Will receive.

In the external gear 30 shown in FIG. 2, the width w _b of the other side frame portion 37b is wider than the width w _a of the one side frame portion 37a. Therefore, the external gear 30 shown in FIG. 2, with respect to the load applied to the external gear 30 in rotation relative to the case 15 in the first direction d _x, the relative casing 15 2 than for the load applied to the external gear 30 when rotated in the direction d _y of, it will have a high stiffness.

Therefore, by the external gear 30 is rotated in the first direction _{d x} with respect to the case 15, the one-way _d ax described with reference to FIG. _6, d _bx, relative rotation eccentric oscillating to _{d cx} The eccentric oscillating gear device 10 having the external gear 30 is caused to lift up the distal arm 2ad relative to the proximal arm 2ap or tighten the fastener. It is preferable to incorporate the robot 1. In other words, by the external gear 30 rotates relative to the case 15 in the second direction _{d y,} another direction _d ay described with reference to FIG. _6, d _By, relative rotation of the _{d cy} eccentric rocking The eccentric oscillating gear device 10 having the external gear 30 is preferably incorporated in the robot 1 so as to be caused in the dynamic gear device 10. In the application of the eccentric oscillating gear device 10 to the robot 1, the external gear 30 exhibits high rigidity when the distal arm 2 ad subjected to a high load is lifted or a fastener is tightened. On the other hand, the external gear 30 exhibits a minimum rigidity commensurate with a low load when the distal arm 2ad is lowered or lowered or when the fastener is loosened.

  As described above, in the external gear 30 and the eccentric oscillating gear device 10 in the first specific example, the external gear 30 has different rigidity depending on the rotation direction of the external gear 30 with respect to the case 15. Become. Therefore, according to the external gear 30 and the eccentric oscillating gear device 10, according to the application of the eccentric oscillating gear device 10 while effectively avoiding the increase in weight due to the enhancement of the overall rigidity. Sufficient rigidity can be exhibited. Thereby, the unexpected damage of the external gear 30 and the eccentric oscillating gear device 10 can be effectively prevented, and the reliability of the external gear 30 and the eccentric oscillating gear device 10 can be effectively improved. it can.

Next, a second specific example of the external gear 30 shown in FIG. 3 will be described. In the first specific example shown in FIG. 2, two through holes 35 are formed between two adjacent insertion holes 33. However, in the external gear 30 according to the second specific example, two adjacent through holes 35 are formed. Only one through hole 35 is formed between the two insertion holes 33. The external gear 30 according to the second specific example differs from the first specific example in the number of through-holes 35, and can be configured identically in other respects. Therefore, in the external gear 30 according to the second specific example, the through hole 35 is located on the other side along the virtual circumference vl than the one side insertion hole 33a located on one side along the virtual circumference vl. It is provided close to the other side insertion hole 33b. Further, the width w _b of the other side frame portion 37b located between one through hole 35 and the one side insertion hole 33a located on one side of the through hole 35 along the virtual circumference vl is the through hole. 35 that is thicker than the width w _a of the one side frame portion 37a which is located between the other side through hole 33b located on the other side of the through hole 35 along the virtual circular vl.

External gear 30 of the second embodiment shown in FIG. 3 having the above configuration, compared load applied at the time of rotating relative to the case 15 in the first direction d _x, with respect to the case 15 than for the load applied at the time of rotation in the second direction d _y Te, so it exhibits a high rigidity. When such an external gear 30 according to the second specific example is used, the same operational effects as when the external gear according to the first specific example is used can be obtained.

Next, a third specific example of the external gear 30 shown in FIGS. 4 and 5 will be described. In the external gear 30 according to the third specific example shown in FIGS. 4 and 5, two through holes 35, a first through hole 35 a and a second through hole 35 b, are provided between two adjacent through holes 33. Is formed. However, as shown in FIG. 4, the arrangement of the two through holes 35a and 35b is located in the middle of the two insertion holes 33 along the virtual circumference vl. Therefore, the external gear 30 of the third embodiment, the width w _a width w _b and one side frame portion 37a of the other side frame portion 37b are the same. The outer contour of the external gear 30 in plan view shown in FIG. 4 is centered on the axis A passing through the center cp and the center axis ca of the two insertion holes 33 adjacent along the virtual circumference vl. It is symmetrical.

  On the other hand, as shown in FIGS. 4 and 5, a reinforcing portion 38 is formed between the two insertion holes 33. The reinforcing portion 38 is closer to the insertion hole located on one side along the virtual circumference vl than the other insertion hole 33b located on the other side along the virtual circumference vl between the two insertion holes 33. ing. In the example shown in FIG. 4, the reinforcing portion 38 is provided on the other side frame portion 37b. The reinforcing part 38 is a part for reinforcing the rigidity of the external gear 30. As shown in FIG. 5, the reinforcing portion 38 can be formed as a bulging portion for increasing the thickness. That is, in the third specific example shown in FIGS. 4 and 5, the thickness of the external gear 30 is asymmetric with respect to the axis A passing through the center cp and the center axis ca of the two insertion holes 33. ing.

As shown in FIG. 5, the external gear 30 of the third embodiment, the thickness t _b of the other side frame portion 37b, is larger than the thickness t _a of one side frame portion 37a. Therefore, in the external gear 30 shown in FIG. 4 and FIG. 5, the external gear 30 is applied to the case 15 with respect to the load applied when rotating in the first direction d _x with respect to the case 15. than for the load applied at the time of rotation in the second direction d _y Te, so it exhibits a high rigidity. When such an external gear 30 according to the third specific example is used, the same operational effects as when the external gear according to the first specific example is used can be obtained.

  In the present embodiment described above, a plurality of insertion holes 33 through which the crankshaft 25 passes are formed on a virtual circumference vl centered on the central axis ca. The external gear 30 has an asymmetric configuration with respect to the axis A passing through the center cp of the two insertion holes 33 adjacent to each other along the virtual circumference vl and the center axis ca of the external gear 30. According to such an external gear 30, the rigidity of the external gear 30 with respect to the external force applied when rotating in one direction and the external gear 30 with respect to the external force applied when rotating in the other direction. Stiffness will be different. Therefore, by incorporating the external gear 30 into the eccentric oscillating gear device 10 so that the external gear 30 has higher rigidity in the rotational direction in which a larger load is applied to the external gear 30, The durability of the external gear 30 can be effectively improved. As a result, the deformation of the external gear 30 can be effectively prevented without depending on the magnitude of the load that is applied to the eccentric oscillating gear device 10 according to the rotation direction. Thereby, the unexpected damage of an external gear can be prevented effectively and the lifetime improvement of the external gear 30 is realizable.

  In the specific example shown in FIG. 2 or FIG. 3, the external gear 30 is formed with a through hole 35 between two insertion holes 33 through which the crankshaft 25 passes. The arrangement of the through holes 35 is shifted from the center cp of the two insertion holes 35. In other words, the through hole 35 is located on the other side along the virtual circumference vl than the one side insertion hole 33a located on the one side along the virtual circumference vl where the insertion holes 33 are arranged. It is located close to the insertion hole 33b. Therefore, by using the through hole 35, the external gear 30 having different rigidity depending on the rotation direction can be realized with a very simple configuration. In addition, as the through hole 35, a hole through which the pillar portion 21a of the carrier 20 passes can be used. In this case, it is possible to prevent a decrease in rigidity of the external gear as a whole caused by newly forming a dedicated hole.

In other words, in the specific example shown in FIG. 2 or FIG. 3, it is located between the one side insertion hole 33 a located on one side along the virtual circumference vl of the two insertion holes 33 and the through hole 35. And the width w _b of the other side frame portion 37b extending in the radial direction to the virtual circumference vl passes through the other side insertion hole 33b located on the other side along the virtual circumference vl of the two insertion holes 33. which is thicker than the width w _a of the virtual circumference vl one side frame portion 37a extending and radially located between the hole 35. That is, the width w _b of the other side frame portion 37b located between the through hole 35 and the one side insertion hole 33a located on one side along the virtual circumference vl is along the through hole 35 and the virtual circumference vl. and it is thicker than the width w _a of the one side frame portion 37a which is located between the other side through hole 33b located on the other side. By adjusting the widths w _a and w _b of the frame portions 37 a and 37 b using the through holes 35, the external gear 30 having different rigidity depending on the rotation direction can be realized with a very simple configuration. . Moreover, as the through hole 35, a hole through which the column portion 21a of the case 20 passes can be used. In this case, it is possible to prevent a decrease in rigidity of the external gear as a whole caused by newly forming the dedicated through hole 35.

Further, in the specific examples shown in FIGS. 4 and 5, the external gear 30 is related to the thickness of the external gear 30 around the axis A passing through the center cp of the two insertion holes 33 and the central axis ca. , Has an asymmetric configuration. By changing the thickness asymmetrically around the predetermined axis A, the external gear 30 having different rigidity depending on the rotation direction can be realized with a very simple configuration. For example, the thickness t _{b of the} region 37b on the other side of the insertion hole 33 along the virtual circumference vl where the insertion holes 33 are arranged is set to be greater than the thickness t _{a of the} region 37a on one side of the insertion hole 33. Increase. In this example, when the case 15 is fixed, the external gear 30 is inserted through the crankshaft 25 when the external gear 30 rotates with the one side of the virtual circumference vl as the front and the other side as the rear. The thick portion reinforces the peripheral portion of the insertion hole 33 from the rear in the moving direction. That is, the external gear 30 is efficiently given high rigidity to the force applied from the crankshaft 25 with such rotation. On the other hand, when the external gear 30 rotates with the other side of the virtual circumference vl as the front and one side as the rear, the rigidity against the load applied to the external gear 30 can be maintained.

  Further, in one embodiment shown in FIGS. 4 and 5, a reinforcing portion 38 is formed in the external gear 30 between two insertion holes 33 through which the crankshaft 25 passes. The reinforcing portion 38 is disposed closer to the one-side insertion hole 33a located on one side along the virtual circumference vl than the other-side insertion hole 33b located on the other side along the virtual circumference vl. . That is, the reinforcing portion 38 is offset from the axis A passing through the center cp and the center axis ca of the two insertion holes 33. According to the installation of the reinforcing portion 38, the external gear 30 having different rigidity depending on the rotation direction can be realized with a very simple configuration. For example, in the state where the case 15 is fixed, the external gear 30 is inserted through the crankshaft 25 when the external gear 30 rotates with the one side of the virtual circumference vl as the front and the other side as the rear. The reinforcing portion 38 reinforces the peripheral portion 33 from the rear in the movement direction of the crankshaft 25. That is, the external gear 30 is efficiently imparted with high rigidity to the force from the crankshaft 25 loaded with such rotation. On the other hand, when the external gear 30 rotates with the other side of the virtual circumference vl as the front and one side as the rear, the rigidity against the load applied to the external gear 30 can be maintained.

In the present embodiment, the robot 1 includes an eccentric oscillating gear device 10 and a pair of arms 2ap, 2bp, 2cp, 2ad, 2bd, 2cd connected via the eccentric oscillating gear device 10; have. The external force applied when the external gear 30 rotates relative to the case 15 having the internal teeth 16 engaged with the external teeth 39 of the external gear 30 in one direction d _ax , d _bx , d _cx. The rigidity of the external gear 30 with respect to the case 15 is stronger than the rigidity of the external gear 30 with respect to the external force applied when the external gear 30 rotates relative to the case 15 in the other directions d _ay , d _by , d _cy. ing. In this robot 1, during the operation of lifting the other arm 2ad, 2bd, 2cd with respect to the one arm 2ap, 2bp, 2cp, the other arm 2ad, 2bd, 2cd is lowered with respect to the one arm 2ap, 2bp, 2cp. A larger load is applied to the external gear 30 than during the lowering operation. Accordingly, the eccentric oscillating gear device 10 operates so as to lift the other arm 2ad, 2bd, 2cd against the weight of the other arm 2ad, 2bd, 2cd with respect to one arm 2ap, 2bp, 2cp. At this time, the external gear 30 preferably rotates relative to the case 15 in one direction d _ax , d _bx , d _cx . According to the application of the eccentric oscillating gear device 10 to the robot 1, the external gear 30 of the eccentric oscillating gear device 10 seems to exhibit stronger rigidity during an operation in which a larger load is applied. become. Therefore, the durability of the eccentric oscillating gear device 10 can be improved, and the life of the eccentric oscillating gear device 10 can be extended.

By the way, the rigidity with respect to the external force applied when rotating relative to one direction d _ax , d _bx , d _cx is more than the rigidity with respect to the external force applied when rotating relative to other directions d _ay , d _by , d _cy. The first eccentric oscillating gear device 10 having the strengthened external gear 30 and the rigidity against the external force applied when rotating relative to d _ax , d _bx , and d _cx in one direction are different from each other. a gear unit group including a second eccentric oscillating gear device 10 having an external gear 30 that is weaker than rigidity against an external force applied when rotating relative to d _ay , d _by , and d _cy. It is preferable to possess. By holding a gear device group including the first eccentric oscillating gear device 10 and the second eccentric oscillating gear device 10, the first eccentric oscillating gear device 10 and the second eccentric oscillating gear device 10 are provided. An appropriate eccentric oscillating gear device 10 can be selected from the dynamic gear device 10. Thereby, damage to the eccentric rocking | fluctuation type gear apparatus 10 which is not intended can be avoided effectively.

  In addition, regarding such a gear device group, the external gear 30 of the first eccentric oscillating gear device 10 and the external gear 30 of the second eccentric oscillating gear device 10 correspond to the eccentric oscillating type. It is preferable that they are gears of the same configuration incorporated in the gear device 10 with the front and back reversed. That is, the first eccentric oscillating gear device 10 and the second eccentric oscillating gear device 10 are prepared by changing the front and back directions of the same external gear 30 as in the embodiment described above. Preferably it can be done. In this case, between the first eccentric oscillating gear device 10 and the second eccentric oscillating gear device 10, the external gear 30 has the same front and back symmetry when the front and back directions are changed, and all configurations are configured. Elements can be common.

  Note that various modifications can be made to the above-described embodiment.

  First, in the third specific example of FIGS. 4 and 5, the reinforcing portion 38 as the bulging portion is formed so that the rigidity of the external gear 30 varies depending on the rotation direction. However, the present invention is not limited to this example, and a reinforcement such as a rib is provided as a reinforcing portion 38 at a portion which is one side or the other side of the insertion hole 33 along the virtual circumference 98 where the insertion holes 33 are arranged. A structure may be provided. Moreover, the weight reduction of the external gear 30 is realized by reducing the thickness of the portion which is one of the insertion hole 33 and the other side along the virtual circumference vl where the insertion holes 33 are arranged. However, the rigidity of the external gear 30 may be varied depending on the rotation direction.

  In the above-described embodiment, the eccentric oscillating gear device 10 includes the two external gears 30 of the first external gear 30a and the second external gear 30b. However, the present invention is not limited to this example, and the eccentric oscillation gear device 10 may include only one external gear 30 or may include three or more external gears 30.

  Further, in the above-described embodiment, the example in which the eccentric oscillating gear device 10 has the three crankshafts 25 is shown, but the present invention is not limited to this example, and the crankshaft 25 may have two crankshafts 25. Four or more crankshafts 25 may be provided.

d _a- axis direction d _r- radial direction a _c rotation axis a _m rotation axis ca center axis vl virtual circumference A axis 1 robot 5 driving device 10 eccentric oscillating gear device 15 case 16 internal teeth 20 carrier 21 first plate 21a column Part 22 second plate 23 support hole 25 crankshaft 26a first eccentric body 26b second eccentric body 27 input gear 30 external gear 30a first external gear 30b second external gear 31 annular main body 33 insertion hole 33a one side Insertion hole 33b Other side insertion hole 35 Through hole 35a First through hole 35b Second through hole 37 Frame part 37a One side frame part 37b Other side frame part 38 Reinforcing part 39 External tooth

Claims (10)

An annular body configured to be rotationally symmetric about a central axis;
And a plurality of external teeth provided along the periphery of the annular body portion about said central axis,
A plurality of insertion holes through which the crankshaft passes are formed in the annular main body portion along a circumference centered on the central axis,
An external gear of an eccentric oscillating gear device, wherein the annular main body is formed asymmetrically around an axis passing through the center of two insertion holes adjacent along the circumference and the central axis. A through hole is formed between the two insertion holes,
The external gear of the eccentric oscillating gear device according to claim 1, wherein the arrangement of the through holes is shifted from the center of the two insertion holes along the circumference. A through hole is formed between the two insertion holes,
Of the two insertion holes, the width of the frame portion located between the insertion hole located on one side along the circumference and the through hole is along the circumference of the two insertion holes. The external gear of the eccentric oscillating gear device according to claim 1 or 2 , wherein the external gear is thicker than a width of a frame portion located between the insertion hole located on the other side and the through hole.   The eccentric oscillation according to any one of claims 1 to 3, which has an asymmetric configuration with respect to the thickness of the external gear, with the axis passing through the center of the two insertion holes and the central axis as the center. External gear of a dynamic gear device. A reinforcing part is formed between the two insertion holes,
The reinforcing portion is closer to an insertion hole located on one side along the circumference than an insertion hole located on the other side along the circumference. External gear of the eccentric oscillating gear device described. An external gear of an eccentric oscillating gear device,
An annular body configured to be rotationally symmetric about a central axis;
A plurality of external teeth provided along the periphery of the annular main body centered on the central axis,
In the state incorporated in the eccentric oscillating gear device, the rigidity with respect to the force applied when rotating in one direction is different from the rigidity with respect to the force applied when rotating in the other direction. External gear of gear device.   The said annular main-body part WHEREIN: The structure between the arbitrary two penetration holes adjacent along the periphery centering on the said center axis line is mutually the same, The any one of Claims 1-6. External gear of the eccentric oscillating gear device. An eccentric oscillating gear device comprising the external gear according to any one of claims 1 to 7 . An eccentric oscillating gear device according to claim 8,
Two arms connected via the eccentric oscillating gear device,
The rigidity of the external gear with respect to the force applied to the external gear when the external gear rotates in one direction relative to the case having the internal teeth engaged with the external teeth of the external gear is The robot is stronger than the rigidity of the external gear against the force applied to the external gear when the external gear rotates in the other direction with respect to the case. A method of using an eccentric oscillating gear device in a robot according to claim 9 ,
When the eccentric oscillating gear device operates to lift the other arm with respect to one of the two arms connected via the eccentric oscillating gear device, the external gear is A method of using an eccentric oscillating gear device to rotate relative to the case in the one direction.

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