KR20160128221A - External gear, eccentric oscillation gear device, robot, method for operating eccentric oscillation gear device and gear device group - Google Patents

Abstract

An external gear (30) comprises multiple external gear teeth (39) installed on the basis of a center axis (ca). Multiple insertion holes (33), through which a crank shaft (25) passes, are formed in the virtual circumference (vl) which uses the central axis (ca) as a center. The external gear (30) is formed to be asymmetrical on the basis of the center (cp) of the two insertion holes (33) adjacent to each other along the virtual circumference and an axis (A) passing through the center axis (ca). Therefore, the present invention extends the service life of the external gear.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eccentric oscillation type gear device, a robot, and a method of using the eccentric oscillation type gear device and a gear device group. More particularly, the present invention relates to an eccentric oscillation type gear device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear unit group including a shout gear used in an eccentric oscillation type gear unit, a robot having an eccentric oscillation type gear unit, a method of using an eccentric oscillation type gear unit, and a plurality of eccentric oscillation type gear units.

For example, as disclosed in JP2014-190451A, an eccentric oscillation type gear device is known. This eccentric oscillating type gear device has a crankshaft having an eccentric body, an external gear having a crankshaft penetrated therethrough, a carrier for holding the crankshaft and external gear, and a case for holding the carrier. In this eccentric oscillating type gear device, when rotation is inputted from the drive device to the crankshaft, the external gear is driven by the eccentric rotation of the eccentric body and moves, that is, oscillates, circumferentially about the central axis. At this time, the external tooth of the external tooth gear is engaged with the internal tooth of the case, so that the external tooth gear rotates about the case. As a result, the rotation input to the crankshaft is outputted as the rotation of the other of the carrier and the case by fixing one of the carrier and the case. In the operation of such a gear device, particularly when it is used as a speed reducer, a large load is applied to the external gear.

Incidentally, depending on the application of the gear device, the load applied to the external gear during one of the rotation in one direction and the rotation in the other direction tends to be larger than the load applied to the external gear during the other rotation operation There are many cases that occur all the time. More specifically, it is possible to use a device for lifting the arm by rotation in one direction and lowering the arm by rotation in the other direction, for example, a robot, or by fastening a fastener by rotation in one direction, This tendency occurs when an eccentric-oscillation-type gear device is applied to a device for loosening a fastener by rotation of the eccentric-oscillation type gear device. The change in the magnitude of the load applied to the external teeth by the rotation direction causes generation of locally large stresses at specific positions of the external teeth, for example, on one tooth surface of the external teeth. When a large locally large stress is generated at a specific position of the external gear, it is necessary to set the life after considering the stress, so that the set life is shortened as compared with the case where no stress is locally generated.

The present invention has been made in view of the above points, and aims to increase the number of gears of the external gear.

The external gear of the first eccentric oscillating type gearing device according to the present invention includes:

And a plurality of external teeth provided around the central axis,

A plurality of insertion holes through which the crankshaft passes are formed on a circumference centered on the central axis,

Symmetrically about the center of two adjacent insertion through holes along the circumference and an axis passing through the center axis.

In the external gear of the first eccentric oscillation type gear device according to the present invention, a through hole is formed between the two insertion through holes, and the arrangement of the through holes is such that the center of the two through- And may be offset.

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

In the external gear of the first eccentric oscillating type gearing device according to the present invention, the center of the two insertion through holes and the axis passing through the center axis line are asymmetric with respect to the thickness of the external gear .

In the external gear of the first eccentric oscillation type gear device according to the present invention, a reinforcing portion is formed between the two insertion through holes, and the reinforcing portion is formed along the circumference of the insertion through hole located on the other side along the circumference. And may be close to the insertion hole located on one side.

The external gear of the second eccentric oscillation type gear device according to the present invention is characterized in that the external gear of the second eccentric oscillation type gear device is configured such that the rigidity against the load applied when rotating in one direction and the load The stiffness to the force is another shout gear.

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

The eccentric oscillation type gear device according to the present invention further includes a case having an internal teeth, a carrier supported by the case, and a crankshaft rotatably supported by the carrier, the crankshaft having an eccentric body, It may engage with the eccentric body of the crankshaft and rock and rotate with respect to the case while engaging with the internal teeth.

In the robot according to the present invention,

The eccentric oscillation type gear device according to the present invention described above and the two arms connected through the eccentric oscillation type gear device,

The stiffness of the external gear relative to the force applied to the external gear when the external gear is relatively rotated with respect to the case having an internal tooth engaging with the external teeth of the external gear, Is stronger than the stiffness of the external gear in relation to the force applied to the external gear.

A method of using an eccentric-pivotal-motion type gear device according to the present invention includes:

In the above-described robot according to the present invention, a method of using an eccentric-

When said eccentric oscillation type gear device is operated so as to lift the other arm with respect to one of the two arms connected via said eccentric oscillation type gear device, said shout gear is rotated relative to said case in said one direction A method of using an eccentric oscillating type gear device.

In the gear device group according to the present invention,

A first eccentric oscillation type gear device having an external gear whose stiffness with respect to a load applied when rotating in one direction is stronger than the stiffness with respect to a force applied when rotating in the other direction,

And a second eccentric oscillation type gear device having an external gear whose rigidity with respect to the load applied when rotating in one direction is weaker than the rigidity with respect to the force applied when rotating in the other direction.

In the gear unit group according to the present invention, the external gears of the first eccentric oscillatory gear device and the external gear of the second eccentric oscillatory gear device are assembled by reversing the front and back of the corresponding eccentric oscillatory gear device And may be a gear having the same configuration.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to improve the durability of external gears and effectively prevent damage to the external teeth. As a result, it is possible to realize the longevity improvement of the external gear.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view for explaining an embodiment of the present invention, showing an eccentric oscillation type gear device having external gears in a cross section passing through its rotation axis; Fig.
Fig. 2 is a plan view showing an example of the external gear incorporated in the eccentric oscillatory gear device; Fig.
3 is a plan view showing another example of the external gear incorporated in the eccentric oscillatory gear device;
4 is a plan view showing still another example of the external gear which is assembled in the eccentric oscillatory gear device;
5 is a sectional view taken along the line VV in Fig.
6 is a perspective view showing a robot as one application example of the eccentric oscillation type gear device.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view showing an eccentric oscillation type gear device. Figs. 2 to 5 are diagrams showing some concrete examples of the external gear according to the present invention. Fig. Fig. 6 is a perspective view showing the robot as one application example of the eccentric-pivotal-motion type gear device.

As shown in Fig. 1, the eccentric oscillatory gear device 10 has a case 15, a carrier 20, a crankshaft 25, and two external gears 30a and 30b. The case 15 has an internal tooth 16. The crankshaft 25 drives the two external gears 30a and 30b and is supported by the carrier 20. This by the eccentric oscillating-type gear 10, the external tooth outer tooth 39 of the gear (30a, 30b), engaged with the internal teeth 16 of the case 15, the carrier 20, the axis of rotation (a _m) So as to rotate relative to the case 15.

The carrier (20) has a first plate (21) and a second plate (22) fixed to each other by fasteners. The first plate 21 has a columnar portion 21a. The first plate 21 is connected to the second plate 22 through the columnar portion 21a. A space for receiving the external gears 30a and 30b is formed between the first plate 21 and the second plate 22 by the column portion 21a. The post 21a passes through a through hole 35 described later of the external gears 30a and 30b. The carrier 20 and the case 15 are rotatably connected to each other by a pair of angular ball bearings 12 around a rotation axis a _m .

The carrier 20 is provided with a support hole 23 through which the first and second plates 21 and 22 are passed. Three support holes 23 are formed on the circumference centered on the axis of rotation a _m at regular intervals. A crankshaft 25 is rotatably supported on each of the three support holes 23 through first and second cylindrical roller bearings 13a and 13b. The rotation axis a _c of the crankshaft 25 is parallel to the relative rotation axis a _m of the case 15 and the carrier 20. Hereinafter, a direction parallel to the relative rotation axis a _{m of the} case 15 and the carrier 20 is referred to as an "axial direction d _a ", and a relative rotation axis a (a) between the case 15 and the carrier 20 _m is referred to as " diameter direction d _{r &} quot ;.

The crankshaft 25 has two eccentric bodies 26a and 26b arranged in the axial direction d _a and an input gear 27. Each of the eccentric bodies 26a, 26b has a disk-like or cylindrical outer shape. The center axes a _ca and a _{cb of the} two eccentric bodies 26a and 26b are symmetrically eccentrically centered on the rotational axis a _c of the crankshaft 25. The two external gears 30a and 30b are arranged in the axial direction d _a in the space formed between the first and second plates 21 and 22 of the carrier 20. An insertion through hole 33 through which the crankshaft 25 passes is formed in each of the external gears 30a and 30b. The insertion through holes 33 of the respective external gears 30a and 30b accommodate the corresponding eccentric bodies 26a and 26b together with the third or fourth cylindrical roller bearings 13c and 13d. Three insertion through holes 33 are formed in each of the external gears 30a and 30b 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 (only one is provided). The outside diameter of the external gears 30a and 30b is slightly smaller than the inside diameter of the internal teeth 16 of the case 15. [

When the torque from the drive device 5 such as a motor is transmitted to the input gear 27 in the eccentric oscillatory gear device 10 having the above configuration, the crankshaft 25 rotates the rotation axis a _c . At this time, the first and second eccentric bodies 26a and 26b eccentrically rotate. As a result, each external tooth gears (30a, 30b) is moved around the relative axis of rotation (a _m). At this time, the external teeth 39 of the external gears 30a and 30b are engaged with the internal teeth 16 of the case 15. As a result, the carrier 20, which rotates the shout gears 30a and 30b against the case 15 and supports the shout gears 30a and 30b through the crankshaft 25, (a _m ), and rotates with respect to the case 15.

This eccentric oscillating type gear device 10 is configured to be used as a speed reducer for turning parts 2a, 2b and 2c (see Fig. 6) constituting a turning body or an arm joint of the robot 1 and turning parts of various machine tools . In the example shown in Fig. 6, one of the proximal side arms (base end side arms) 2ap, 2bp, 2cp and the distal side arm (distal end side arms) 2ad, 2bd, 2cd, 2bp and 2cp with respect to the proximal side arms 2ap, 2bp and 2cp by fixing the case 15 of the gear device 10 and fixing the carrier 20 of the eccentric oscillatory gear device 10 to the other side. The relative positions of the distal arms 2ad, 2bd, and 2cd relative to the proximal arms 2ap, 2bp, and 2cp can be controlled with high accuracy while rotating the distal arms 2ad, 2bd, and 2cd with high torque.

When the carrier 20 and the case 15 relatively rotate, the external gears 30a and 30b receive a load from the internal teeth 16 engaged with the external teeth 39 around the external teeth 39 . The external gears 30a and 30b also receive a load from the crankshaft 25 passing through the insertion through hole 33 around the insertion hole 33. [ Particularly, in the eccentric oscillation type gear device 10 used as the transmission, the load becomes relatively large. The load applied to the external gears 30a and 30b causes deformation of the external gears 30a and 30b and further damage to the external gears 30a and 30b. In the application of the eccentric oscillatory gear device 10 as described in the prior art, the eccentric oscillatory gear device 10 is loaded on the external gears 30a and 30b during one of the rotation in one direction and the rotation in the other direction The load tends to become larger than the load applied to the external gears 30a and 30b during the other operation.

6, when the carrier 20 and the case 15 are relatively rotated in the one direction d _ax , the weight of the distal arm 2ad So that the distal arm 2ad is lifted with respect to the proximal arm 2ap. On the other hand, when the carrier 20 and the case 15 relatively rotate in the other direction d _ay , the distal arm 2ad is lowered with respect to the proximal arm 2ap. When the carrier 20 and the case 15 relatively rotate in the one direction d _bx , the distal side arm 2bd is lifted and the carrier 20 and the case 15 15 are relatively rotated in the other direction d _by , the lower arm 2bd is lowered. Therefore, in the eccentric oscillatory gear device 10 applied to the first swivel portion 2a and the second swivel portion 2b, when the carrier 20 and the case 15 relatively rotate in the one direction d _ax , d _bx The load applied to the external gears 30a and 30b becomes larger than the load applied to the external gears 30a and 30b when the carrier 20 and the case 15 relatively rotate in the other direction d _ay and d _by .

When the tool for fastening the fastening tool is mounted on the distal end portion of the robot 1, the carrier 20 and the case 15 in the third swivel portion 2c of the robot 1 are _opposed in the one direction d _cx By rotating, the fastener can be fastened. On the other hand, when the carrier 20 and the case 15 are relatively rotated in the other direction d _cx , the fastener can be released. Therefore, in the eccentric oscillatory gear device 10 applied to the third swivel portion 2c, when the case 15 and the carrier 20 relatively rotate in the one direction d _cy , the load (load) applied to the external gears 30a and 30b 30b becomes larger than the load applied to the external gears 30a, 30b when the case 15 and the carrier 20 relatively rotate in the other direction d _cy .

The change in the load applied to the external gear in the rotational direction in this way means that a large stress concentrates on a specific position of the external gear, for example, one tooth surface of the external teeth. In the case where a large stress is locally generated in the external gear, it is necessary to set the life after considering the stress, so that the set life is shortened as compared with the case where no stress occurs locally.

In the application of the gear device 10, the time during which the carrier 20 and the case 15 relatively rotate in one direction may be significantly longer than the time during which the carrier 20 and the case 15 relatively rotate in the other direction. In this case, stress acts on a specific position of the external gear, for example, a tooth surface of the external gear, for a long time. Also in this example, since it is necessary to set the life after considering the stress, the set life is shortened as compared with the case where no stress occurs over a long period of time.

Therefore, in the eccentric oscillation type gear device 10 described herein, the rigidity of the external gears 30a and 30b with respect to the external force applied when the relative rotation is performed in the one direction d _ax , d _bx , and d _cx , The stiffness of the external gears 30a and 30b with respect to the external force applied when the external gears 30a and 30b are different is different. That is, the stiffness of the cogs 30a and 30b is not simply improved as a whole, but the load that causes unexpected damage, that is, the rigidity against the large stress generated in the one rotation direction is improved. By improving the rigidity, the stress generated in the external gears 30a and 30b can be reduced. This makes it possible to prevent the gears 30a and 30b and the eccentric rocking type gear device 10 from becoming significantly large in size while preventing the striking gears 30a and 30b So that the longevity of the external gears 30a and 30b is increased.

Hereinafter, the external gears 30a and 30b will be described in more detail. The phases of the first external gear 30a and the second external gear 30b in the assembled state of the eccentric oscillatory gear device 10 are only 180 degrees (eccentric from the relative rotational axis a _m ) The direction is reversed) and can be formed as the same gear. Therefore, for the description common to the first external gear 30a and the second external gear 30b, reference numeral 30 is used to distinguish the first external gear 30a and the second external gear 30b .

2 to 5 to be described later, the shout gear 30 includes an annular main body portion 31 and an outer tooth portion 39 arranged along the periphery of the annular main body portion 31, . As described above, the external teeth 39 are engaged with the internal teeth 16 of the case 15. The annular main body portion 31 of the external gear 30 is provided with three insertion through holes 33 through which the crankshaft 25 is inserted. The three insertion through holes 33 are arranged on an imaginary circumference vl centered on the central axis ca of the external gear 30 at regular intervals. The shout gear 30 has an axis A passing through the center cp and the central axis ca of the two adjacent insertion through holes 33 along the virtual circumference vl And is formed asymmetrically with respect to the center.

Also, the center axis ca of the external gear 30 forms the center of the array of the external teeth 39. External tooth gear 30 is in a state assembled in the eccentric oscillating-type gear device 10, the center axis (ca), is parallel to the casing 15 and the relative axis of rotation of the carrier (20), (a _m). However, the external tooth center axis (ca) of the gear (30), as the eccentricity of the eccentric element (26a, 26b) of the crank shaft 25, are offset from the relative axis of rotation (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 embodiment, the through hole 35 is formed in the annular main body portion 31 of the external gear 30. The through hole 35 is a portion through which the columnar portion 21a of the carrier 20 passes (see Fig. 1). The through hole 35 is normally provided in the carrier 20 adopting the structure in which the first plate 21 and the second plate 22 are coupled through the columnar portion 21a. 2, the through hole 35 is formed at a position between two adjacent insertion through holes 33 (33a, 33b) along the virtual circumference v1. Particularly, in the first specific example shown in Fig. 2, first through holes 35a and second through holes 35b are formed between adjacent two through-holes 33, respectively. The arrangement of the two through holes 35a and 35b is offset from the center cp of the two insertion through holes 33 (33a and 33b) along the virtual circumference v1. That is, the two through holes 35a and 35b are formed in the other side through hole 33b located on the other side along the virtual circumference vl, rather than the one side through hole 33a located on one side along the virtual circumference vl ). However, in the annular main body portion 31 of the external gear 30, the configuration between any two insertion through holes 33 adjacent to each other along the virtual circumference vl becomes equal to each other. That is, the annular main body portion 31 of the shout gear 30 is generally rotationally symmetric with respect to the central axis ca, more specifically, three times symmetrical.

2, in the external gear 30 having such a configuration, the annular main body portion 31 has the virtual circumference vl (the right side in the figure) than the one side of the insertion through hole 33 along the virtual circumference vl A large portion is provided on the other side of the insertion hole 33 corresponding to the insertion hole 33. [ In other words, the other frame portion 37b partitioned by one through hole 33 and the through hole 35 (35a) located on the other side of the through hole 33 along the virtual circumference v1, The width w _b of the through hole 33 is formed along one of the through holes 35 and 35b formed in one side of the insertion through hole 33 along the virtual through hole 33 and the virtual circumference vl 37a) it is wider than the width w _a of.

The shout gear 30 is rotated in the first direction (in Fig. 2) with the one side along the virtual circumference v1 forward and the other along the virtual circumference vl backward with respect to the fixed case 15 Let the counterclockwise direction) rotated hayeotdago d _x. At this time, the shout gear 30 operates together with the carrier 20 through the crankshaft 25 located in the insertion through hole 33. Therefore, the external gear 30 receives a reaction force from the crankshaft 25 in the direction opposite to the rotating direction. That is, when rotating in the first direction d _x , the shout gear 30 is located in the region located on the other side of the insertion hole 33 along the virtual circumference vl, that is, in the other frame portion 37b, (25). Conversely, when the shout gear 30 rotates in the second direction (Fig. 2 (b)) in which the other side along the imaginary circumference vl is forward with respect to the fixed case 15 and the other side along the virtual circumference vl is rearward When clockwise) rotated by d _y in, outer tooth gear 30 is a crank shaft in an area, that is, one side of the frame portion (37a) which is located on one side of the through hole 33 along a virtual circumference (vl) ( 25).

In the outer tooth gear 30, shown in Figure 2, the width w _b of the other side frame member (37b), it is wider than the width w _a of the one side frame member (37a). Therefore, the external gear 30 shown in Fig. 2 is configured such that when the case 15 is rotated in the first direction d _x with respect to the load applied to the external gear 30, And has a stiffness higher than that for the load applied to the external gear 30 when it rotates in the direction d _y .

Accordingly, the external tooth gear 30 is, referring to Figure 6 the one-way d _ax, d _bx, d _cx relative rotation of the eccentric oscillating-type gear set 10 to the above with, by rotating in the first direction d _x for the case 15 So that the eccentric pivotal gear device 10 having the external gear 30 is lifted up by the robot 20 so as to lift the distal arm 2ad against the proximal arm 2ap or to fasten the fastener. It is preferable to assemble them to the main body 1. In other words, when the external gear 30 rotates in the second direction d _y with respect to the case 15, the relative rotation to the other directions d _ay , d _by , d _cy described with reference to Fig. 6 is _{detected by the} eccentric- It is preferable to assemble the eccentric oscillation type gear device 10 having the external gear 30 to the robot 1 so that the eccentric oscillation type gear device 10 is caused within the robot 10. In applying the eccentric oscillatory gear device 10 to the robot 1, the external gear 30 exhibits high rigidity at the time of lifting the distal arm 2ad to which the high load is applied or when fastening the fastener. On the other hand, when the lower arm 2ad is lowered or the fastener is loosened, the external gear 30 exhibits the minimum rigidity suitable for the low load.

As described above, in the external gear 30 and the eccentric oscillatory gear device 10 according to the first embodiment, the external gear 30 is rotated in the direction of rotation of the external gear 30 with respect to the case 15, Have different stiffness. Therefore, with this external gear 30 and the eccentric oscillation type gear device 10, it is possible to effectively prevent the large-sized weight due to the strengthening of the whole rigidity and to secure sufficient rigidity according to the application of the eccentric- . As a result, unexpected damage of the external gear 30 and the eccentric oscillation type gear device 10 can be effectively prevented, and the reliability of the external gear 30 and the eccentric oscillation type gear device 10 can be effectively improved.

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 through holes 33. In the external tooth gear 30 according to the second specific example, Only one through hole 35 is formed between the two insertion through-holes 33. [ The external gear 30 according to the second specific example differs from that of the first specific example in the number of the through holes 35 and can be otherwise configured in the same manner. Therefore, in the external gear 30 relating to the second specific example, the through hole 35 is formed on the other side along the virtual circumference vl than the one side through hole 33a located on one side along the virtual circumference vl And is formed in the vicinity of the other side insertion through hole 33b. The width w _b of the other side frame portion 37b located between one through hole 35 and one side through hole 33a located on one side of the through hole 35 along the virtual circumference vl is, than the width w _a of the art through-hole 35 and the virtual circumferential side frame portion (37a) positioned between the other side through holes (33b) which is located at the other side of the through hole 35, the art according to (vl) It is bold.

The external gear 30 according to the second specific example shown in Fig. 3 having the above-described configuration is configured so that the load applied to the case 15 when the case 15 is rotated in the first direction d _x It exhibits higher rigidity than the load applied when rotating in two directions d _y . When the external gear 30 according to the second specific example is used, the same operational effects as those obtained 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 concrete example shown in Figs. 4 and 5, the first through hole 35a and the second through hole 35b are formed between adjacent two through holes 33, Two through holes 35 are 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 through holes 33 along the virtual circumference v1. Therefore, in the external gear 30 according to the third specific example, the width w _b of the other side frame portion 37 _b is equal to the width w _a of the one side frame portion 37 _a . The outer contour of the external gear 30 as seen in the plane shown in Fig. 4 is defined by the center cp of the two adjacent insertion through holes 33 along the virtual circumference vl and the center axis ca And is symmetrical with respect to the axis A passing therethrough.

On the other hand, as shown in Figs. 4 and 5, reinforcing portions 38 are formed between the two insertion through-holes 33. As shown in Fig. The reinforcing portion 38 is located between the two insertion through holes 33 on one side along the imaginary circumference vl than the other insertion through hole 33b located on the other side along the virtual circumference vl And is close to the insertion hole. In the example shown in Fig. 4, the reinforcing portion 38 is provided on the other side frame portion 37b. The reinforcing portion 38 is a portion for reinforcing the rigidity of the external gear 30. As shown in Fig. 5, the reinforcing portion 38 may be formed as a bulging portion for increasing the thickness. That is, in the third specific example shown in Figs. 4 and 5, the axis line A passing through the center cp of the two through-holes 33 and the central axis ca is the center, 30 are asymmetric with respect to the thickness.

As shown in Fig. 5, it is in the external tooth gear 30 of the third embodiment, thicker than the thickness t _a of the other side frame member thickness t _b is, one frame part (37a) of (37b). Therefore, in the external gear 30 shown in Figs. 4 and 5, the external gear 30 is configured so that the load applied to the case 15 when rotating in the first direction d _x Which is higher than that of the load applied when rotating in the second direction d _y . When the external gear 30 according to the third specific example is used, the same operational effects as those obtained when the external gear according to the first specific example is used can be obtained.

In the above-described embodiment, a plurality of insertion through holes 33 through which the crankshaft 25 passes are formed on the imaginary circumference v1 centered on the central axis ca. With respect to the axis A passing through the center cp of the two adjacent insertion through holes 33 along the virtual circumference vl and the central axis ca of the external gear 30, Asymmetric configuration. With this external gear 30, the rigidity of the external gear 30 with respect to the external force applied when rotating in one direction and the rigidity of the external gear 30 with respect to the external force applied when rotating in the other direction, Different. Therefore, by assembling the external gear 30 to the eccentric oscillation type gear device 10 so that the external gear 30 has a higher rigidity in the rotating 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 imposed on the eccentric oscillating type gear device 10 in accordance with the rotational direction. Thereby, unexpected breakage of the external gear can be effectively prevented, and the longevity of the external gear 30 can be increased.

2 or 3, a through hole 35 is formed in the external gear 30 between the two insertion through holes 33 through which the crankshaft 25 passes have. The arrangement of the through holes 35 is shifted from the center cp of the two insertion through holes 35. [ In other words, the through hole 35 is located on the other side along the virtual circumference vl, rather than the one side through hole 33a located on one side along the virtual circumference vl on which the insertion through hole 33 is arranged The other side insertion through-hole 33b is formed. Therefore, by using this through hole 35, the external gear 30 having a different rigidity in the rotating direction can be realized by an extremely simple structure. In addition, as the through hole 35, a hole through which the columnar portion 21a of the carrier 20 passes can be used. In this case, it is possible to prevent the overall rigidity of the external gear from deteriorating due to the formation of a dedicated hole.

In other words, in the embodiment shown in Fig. 2 or Fig. 3, one of the two insertion through holes 33, which is located at one side along the virtual circumference vl, And the width w _b of the other side frame portion 37b extending in the radial direction to the imaginary circumference vl is smaller than the width wb of the other side insertion portion 33 located on the other side along the virtual circumference vl of the two insertion through holes 33 Is larger than the width w _a of the imaginary circumference v 1 of one frame portion 37 a located between the through hole 33 b and the through hole 35 and extending in the radial direction. That is, the width w _b of the other side frame portion 37b positioned between the through hole 35 and one side through hole 33a located on one side along the virtual circumference vl is smaller than the width w _b of the through hole 35 the width w _a of the side frame portion (37a) which is located between the other side through holes (33b) which is located at the other side along a virtual circumference (vl) than are in bold. By adjusting the widths w _a and w _b of the frame portions 37a and 37b using the through holes 35, the external gear 30 having a different rigidity in the rotating direction can be realized by an extremely simple structure . In addition, as the through hole 35, a hole through which the columnar portion 21a of the case 20 passes can be used. In this case, it is possible to prevent the overall rigidity of the external gear from deteriorating due to the formation of the dedicated through-hole 35.

4 and 5, the shout gear 30 is configured so that the axis A passing through the center cp and the central axis ca of the two insertion through holes 33 is a center And has an asymmetrical configuration with respect to the thickness of the external gear 30. By changing the thickness asymmetrically about the predetermined axis A, the external gear 30 having different rigidity according to the rotational direction can be realized by an extremely simple configuration. For example, the thickness t _b of the region 37b serving as the other side of the insertion through hole 33 along the virtual circumference vl in which the insertion through hole 33 is arranged is set to be larger than the thickness t _b of the other side of the insertion through hole 33 Is greater than the thickness t _a of the region 37a. In this example, when the external gear 30 rotates one side of the imaginary circumference vl forward and the other side backward while the case 15 is fixed, the crankshaft 25) of the insertion hole (33), the back portion is reinforced from the rear side in the moving direction. That is, the external gear 30 is efficiently given high rigidity to the force applied from the crankshaft 25 in accordance with such rotation. On the other hand, when the external gear 30 rotates with the other side of the virtual circumference v1 forward and the other side rearward, the rigidity against the load applied to the external gear 30 can be maintained.

4 and 5, the reinforcing portion 38 is formed in the external gear 30 between the two insertion through holes 33 through which the crankshaft 25 passes. In the embodiment shown in Figs. 4 and 5, . The reinforcing portion 38 is disposed closer to one side insertion through hole 33a located on one side along the virtual circumference vl than the other side insertion through hole 33b located on the other side along the virtual circumference vl have. That is, the reinforcing portion 38 is offset from the axis A passing through the center cp of the two through-holes 33 and the central axis ca. With the provision of the reinforcing portion 38, the external gear 30 having different rigidity in the rotating direction can be realized by an extremely simple structure. For example, when the shout gear 30 rotates one side of the virtual circumference vl forward and the other shunt rearward with the case 15 fixed, the crankshaft < RTI ID = 0.0 & The reinforcing portion 38 reinforces the peripheral portion of the insertion through hole 33 through which the reinforcing portion 25 is inserted from behind the moving direction of the crankshaft 25. [ That is, the shout gear 30 is efficiently provided with high rigidity against the force from the crankshaft 25 which is loaded with such rotation. On the other hand, when the external gear 30 rotates with the other side of the virtual circumference v1 forward and the other side rearward, the rigidity against the load applied to the external gear 30 can be maintained.

In this embodiment, the robot 1 includes a pair of arms 2ap, 2bp, 2cp, 2ad, and 2bd connected to the eccentric oscillation type gear unit 10 via the eccentric oscillation type gear unit 10, , And 2cd. The external force to be applied when the external gear 30 relatively rotates in the one direction d _ax , d _bx , d _cx with respect to the case 15 having the internal teeth 16 engaged with the external teeth 39 of the external gear 30, external tooth rigidity of the gear 30 on the, outer tooth on the casing 15 gear 30, the second direction d _ay, d _by, external tooth rigidity of the gear 30 with respect to the external force load when the rotation relative to the d _cy . 2bp and 2cp in the operation of lifting the other arm 2ad, 2bd and 2cd with respect to one arm 2ap, 2bp and 2cp, A large load is loaded on the external gear 30, as compared with the operation of lowering the arms 2ad, 2bd, 2cd on the side of the external gear. Therefore, the eccentric-pivotal-type gear device (2d, 2bd, 2cd) is configured so as to lift the other arm (2ad, 2bd, 2cd) against one arm (2ap, 2bp, 2cp) against the self weight of the other arm It is preferable that the shout gear 30 relatively rotate in one direction d _ax , d _bx , d _cx with respect to the case 15 when the shout gear 10 operates. By applying the eccentric oscillatory gear device 10 to the robot 1, the external gear 30 of the eccentric oscillatory gear device 10 exhibits stronger rigidity during operation in which a larger load is applied . Therefore, the durability of the eccentric-pivotal-type gear device 10 can be improved and the life of the eccentric-pivotal-type gear device 10 can be increased.

However, the outer tooth in the rigidity against an external force that the load upon relative rotation in one direction d _ax, d _bx, d _cx, is stronger than the rigidity against an external force that the load upon rotation relative to the second direction d _ay, d _by, d _cy and a first eccentric oscillating-type gear set 10 having a gear 30, the one-way d _ax, d _bx, the rigidity against an external force that the load upon rotation relative to the d _cx, second direction d _ay, d _by, d _cy And a second eccentric oscillation type gear device (10) having an external gear (30) that is weaker than the external force applied when an external force is applied to the first eccentric oscillation type gear device (10). The first eccentric oscillation type gear device 10 and the second eccentric oscillation type gear device 10 are provided so that the first eccentric oscillation type gear device 10 and the second eccentric oscillation type gear device 10, It becomes possible to select an appropriate eccentric oscillating type gear device 10 from the apparatus 10. [ Thus, damage to the unintentional eccentrically oscillating type gear device 10 can be effectively avoided.

The gear teeth group 30 of the first eccentric oscillatory gear device 10 and the gear teeth 30 of the second eccentric oscillatory gear device 10 are connected to the corresponding eccentric oscillating gears 10, It is preferable that gears having the same configuration are assembled with the front and back of the device 10 reversed. That is, the first eccentric oscillation type gear device 10 and the second eccentric fluctuation type gear device 10 can be prepared by changing the front and back directions of the same external gear 30 as in the above-described one embodiment desirable. In this case, between the first eccentric oscillation type gear device 10 and the second eccentric oscillation type gear device 10, the external gear 30 is symmetrical in the front and rear direction when the direction of the front and back is changed, Elements can be common.

It is also possible to make various modifications to the above-described embodiment.

First, in the third specific example shown in Figs. 4 and 5, by forming the reinforcing portion 38 as the swelling portion, the stiffness of the external gear 30 is made to be different according to the rotating direction. However, the reinforcing portion 38 is not limited to this example, and may be formed as a reinforcing portion 38 at a portion of one side or the other of the insertion through hole 33 along the virtual circumference 98 on which the insertion through- , Ribs, or the like may be provided. In addition, by reducing the thickness of the portion of one side or the other side of the insertion through hole 33 along the virtual circumference vl on which the insertion through holes 33 are arranged, the weight of the external tooth gear 30 can be reduced , And the stiffness of the external gear 30 may vary according to the rotating direction.

The eccentric rocking type gear device 10 shown in the above embodiment has an example in which the two external gears 30 of the first external gear 30a and the second external gear 30b are included. However, the present invention is not limited to this example, and the eccentric oscillatory gear device 10 may include only one external gear 30, or three or more external gears 30.

Although the eccentric oscillatory gear device 10 has three crankshafts 25 in the above-described embodiment, the present invention is not limited to this example. Even if the eccentric oscillatory gear device 10 has two crankshafts 25 And four or more crankshafts 25 may be provided.

Claims (11)

And a plurality of external teeth provided around the central axis,
A plurality of insertion holes through which the crankshaft passes are formed along a circumference centered on the central axis,
Wherein said gear is formed asymmetrically about the center of two adjacent insertion through holes along said circumference and an axis passing through said center axis. The method according to claim 1,
A through hole is formed between the two insertion through holes,
Wherein the arrangement of the through holes is shifted from the center of the two insertion through holes along the circumference of the eccentric oscillation type gear device. The method according to claim 1,
A through hole is formed between the two insertion through holes,
And a width of the frame portion located between the through-hole and the through-hole located on one side of the two through-holes, the through-hole being located on the other of the two through- And the width of the frame portion located between the through holes is larger than the width of the frame portion located between the through holes. The method according to claim 1,
And a center axis of the two insertion through holes and a center axis passing through the center axis, and having an asymmetrical configuration with respect to a thickness of the external gear. The method according to claim 1,
A reinforcing portion is formed between the two insertion through holes,
Wherein the reinforcing portion is closer to the insertion through hole located on one side along the circumference than the insertion through hole located on the other side along the circumference. An external gear of an eccentric oscillating type gear device,
Wherein the stiffness with respect to the force applied when rotating in one direction and the stiffness with respect to the force applied when rotating in the other direction are different from each other in the assembled state of the eccentric oscillatory gear device. An eccentric oscillating type gear device comprising the external gear according to any one of claims 1 to 6. An eccentric oscillation type gear device according to claim 7,
And two arms connected through the eccentric oscillation type gear unit,
The stiffness of the external gear relative to the force applied to the external gear when the external gear is relatively rotated with respect to the case having an internal tooth engaging with the external teeth of the external gear, Is stronger than the stiffness of the external gear in relation to the force applied to the external gear. A method of using an eccentric-pivotal-motion type gear device in a robot according to claim 8,
When said eccentric oscillation type gear device is operated so as to lift the other arm with respect to one of the two arms connected via said eccentric oscillation type gear device, said shout gear is rotated relative to said case in said one direction Using an eccentric oscillating type gear device. A first eccentric oscillation type gear device having an external gear whose stiffness with respect to a load applied when rotating in one direction is stronger than the stiffness with respect to a force applied when rotating in the other direction,
And a second eccentric oscillation type gear device having a gear having a stiffness with respect to a force applied when rotating in one direction is weaker than a stiffness with respect to a force applied when rotating in the other direction. 11. The method of claim 10,
Wherein said external gear of said first eccentric oscillation type gear device and said external gear of said second eccentric oscillating type gear device are gears of the same configuration assembled with the corresponding eccentric oscillation type gear device reversed front and rear, .

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