JP7149158B2 - Eccentric oscillating reduction gear - Google Patents

Description

The present invention relates to an eccentric oscillating speed reducer.

Patent Document 1 describes an eccentric oscillating gear device. A gear device disclosed in Patent Document 1 includes an outer cylinder and a carrier, and the outer cylinder is fixed to transmit rotation from the carrier to a mating member.

JP 2017-155772 A

In the gear device disclosed in Patent Literature 1, an output shaft portion is press-fitted and fixed in a central hole of a carrier, and rotation is transmitted to a mating member by the output shaft portion. Concavities and convexities are formed on the inner peripheral surface of the center hole of the carrier and the outer peripheral surface of the output shaft portion. However, according to the study of the present inventor, it has been found that in this configuration, the coupling strength between the carrier and the output shaft is low, so that the torque transmitted to the output shaft is insufficient.
Based on these findings, the inventors of the present invention have recognized that the gear device described in Patent Literature 1 has problems to be solved in terms of improving the strength of connection between the carrier and the output shaft portion.

SUMMARY OF THE INVENTION An object of the present invention is to provide an eccentric oscillating speed reducer capable of improving the strength of connection between the protruding shaft and the carrier.

In order to solve the above problems, an eccentric oscillating type reduction gear transmission according to one aspect of the present invention includes an internal gear, an external gear, and an external gear arranged offset from the axis of the internal gear to oscillate the external gear. a first carrier arranged on one side in the axial direction of the external gear and synchronized with the rotation of the external gear; and a second carrier arranged on the other side in the axial direction of the external gear and connected to the first carrier. and an eccentric oscillating type speed reducer. the first carrier has a first central hole in its radial center and the second carrier has a second central hole in its radial center and fits in both the first and second central holes; It has a projecting shaft projecting axially outwardly from at least the first central hole.

Arbitrary combinations of the above constituent elements, and mutually replacing the constituent elements and expressions of the present invention in methods, systems, etc. are also effective as aspects of the present invention.

According to the present invention, it is possible to provide an eccentric oscillating speed reducer capable of improving the connection strength between the projecting shaft and the carrier.

1 is a side cross-sectional view showing an eccentric oscillating speed reducer according to an embodiment; FIG. 2 is a view showing a central hole of a carrier of the eccentric oscillating speed reducer of FIG. 1; FIG. It is a side cross-sectional view showing an eccentric oscillation type reduction gear transmission of a first modification. FIG. 11 is a side cross-sectional view showing an eccentric oscillating reduction gear transmission of a second modified example; FIG. 11 is a side cross-sectional view showing an eccentric oscillating reduction gear transmission of a third modified example;

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on preferred embodiments with reference to the drawings. In the embodiments and modified examples, the same or equivalent constituent elements and members are denoted by the same reference numerals, and duplication of description will be omitted as appropriate. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Also, in each drawing, some of the members that are not important for explaining the embodiments are omitted.
Also, terms including ordinal numbers such as first, second, etc. are used to describe various components, but these terms are used only for the purpose of distinguishing one component from other components, and the terms The constituent elements are not limited by

[Embodiment]
Hereinafter, the configuration of an eccentric oscillation type reduction gear transmission 10 according to an embodiment will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a side cross-sectional view showing an eccentric oscillating speed reducer 10 according to an embodiment. The eccentric oscillating speed reducer 10 of the present embodiment is a so-called distribution type eccentric oscillating speed reducer. The eccentric oscillating speed reducer 10 oscillates the external gear that meshes with the internal gear to cause rotation of one of the internal gear and the external gear, and the generated rotation component is received from the output member. configured to output to a drive;

The eccentric oscillating speed reducer 10 mainly includes an input gear 70, a crankshaft 12, an external gear 14, an internal gear 16, carriers 18, 20, a casing 22, and main bearings 24, 26. , and a projecting shaft 40 . Hereinafter, the direction along the central axis La of the internal gear 16 will be referred to as the "axial direction", and the circumferential direction and the radial direction of a circle centered on the central axis La will be referred to as the "circumferential direction" and the "radial direction", respectively. do. Further, hereinafter, for the sake of convenience, one side in the axial direction (right side in the drawing) will be referred to as the input side, and the other side (left side in the drawing) will be referred to as the anti-input side.

(input gear)
Three input gears 70 are arranged around the center axis La of the internal gear 16 . The three input gears 70 are arranged at equal intervals of 120° at positions offset from the central axis La. Only one input gear 70 is shown in FIG. Three crankshafts 12 are provided corresponding to the three input gears 70 . The crankshaft 12 is inserted through the center of the input gear 70 and supports the input gear 70 . A pair of crankshaft bearings 34 are provided on both axial sides of the crankshaft 12 . The crankshaft 12 is provided rotatably integrally with the input gear 70 . The three input gears 70 are meshed with external teeth of a rotary shaft (not shown) provided on the center axis La. Rotational power is transmitted to this rotating shaft from a driving device (not shown), and the rotation of the rotating shaft causes the input gear 70 to rotate integrally with the crankshaft 12 . The drive device is, for example, a motor, gear motor, engine, or the like.

(crankshaft)
The crankshaft 12 of this embodiment is an eccentric shaft having a plurality of eccentric portions 12a for swinging the external gear 14 . The axis of the eccentric portion 12 a is eccentric with respect to the rotation center line of the crankshaft 12 . In this embodiment, two eccentric portions 12a are provided, and the eccentric phases of adjacent eccentric portions 12a are shifted by 180°.

The crankshaft 12 has its input side supported by the second carrier 20 via a crankshaft bearing 34 and its counter-input side supported by the first carrier 18 via a crankshaft bearing 34 . The counter-input-side crankshaft bearing 34 is fitted into and supported by the crankshaft hole 18h of the first carrier 18, and the input-side crankshaft bearing 34 is fitted into and supported by the crankshaft hole 20h of the second carrier 20. That is, the crankshaft 12 is rotatably supported with respect to the first carrier 18 and the second carrier 20 . The crankshaft bearing 34 is a roller bearing having cylindrical rolling elements in this example, although there is no particular restriction on its configuration.

(Internal gear)
The internal gear 16 meshes with the external gear 14 . The internal gear 16 of the present embodiment includes an internal gear body 16a integrated with the casing 22, and external gears arranged in a plurality of pin grooves formed in the internal gear body 16a at intervals in the circumferential direction. a pin 17; The outer pin 17 is a cylindrical pin member rotatably supported by the internal gear body 16a. The outer pin 17 may be a hollow member, but is a solid member in this embodiment. The outer pin 17 constitutes the inner teeth of the internal gear 16 . The number of external pins 17 (the number of internal teeth) of the internal gear 16 is slightly greater than the number of external teeth of the external gear 14 (by one in this example).

(external gear)
The external gear 14 is individually provided corresponding to each of the plurality of eccentric portions 12a. The external gear 14 is rotatably supported by the corresponding eccentric portion 12 a via the eccentric rollers 32 . In the external gear 14, three shaft holes 14p and three swing holes 14j are formed at predetermined intervals at positions offset from the axis.

The shaft holes 14p are provided at 120° intervals at the same radial position. The shaft hole 14p penetrates in the axial direction, and the shaft portion 18s is inserted therethrough. The shaft hole 14p is formed larger than the outer diameter of the shaft portion 18s and has a size that does not come into contact with the shaft portion 18s.

The swing holes 14j are provided at 120° intervals at the same radial position. The swing hole 14j penetrates in the axial direction, and the eccentric portion 12a of the crankshaft 12 is inserted therethrough. The swing hole 14j is formed larger than the outer diameter of the eccentric portion 12a, and a plurality of eccentric rollers 34 are interposed between the swing hole 14j and the eccentric portion 12a. The plurality of eccentric rollers 34 are arranged around the eccentric portion 12a at substantially equal intervals, and smoothly transmit the eccentric motion of the eccentric portion 12a to the swing hole 14j.

The external gear 14 is provided with a central hole 14h through which a projecting shaft 40 (to be described later) penetrates. The central hole 14 h is a hole provided in the radial center of the external gear 14 , is formed to be larger than the outermost diameter of the protruding shaft 40 , and has a size that does not come into contact with the protruding shaft 40 . Although the shape of the central hole 14h is not limited, the central hole 14h in this example is circular.

Waveform teeth are formed on the outer periphery of the external gear 14, and the teeth move while being in contact with the internal gear 16, thereby causing the external gear 14 to oscillate within a plane normal to the central axis. It is possible.

(carrier)
The carriers 18 , 20 are arranged on the axial sides of the external gear 14 . The carriers 18 and 20 include a first carrier 18 arranged on the side of the external gear 14 opposite to the input side, and a second carrier 20 arranged on the side of the external gear 14 on the input side. be Hereinafter, when collectively referring to the first carrier 18 and the second carrier 20, they will be referred to as "carriers". The carrier is rotatably supported by casing 22 via first main bearing 24 and second main bearing 26 . The carrier generally has the shape of a hollow disc or cylinder. The carrier rotatably supports crankshaft 12 via crankshaft bearings 34 .

(central hole)
The first carrier 18 has a first central hole 18j formed in the radial center of the first carrier 18 . The second carrier 20 has a first central hole 20j formed in the center of the second carrier 20 in the radial direction. The first central hole 18j is a hole that has a circular shape as a whole and penetrates in the axial direction. The second central hole 20j is a hole that has a circular shape as a whole and penetrates in the axial direction. Hereinafter, the first central hole 18j and the second central hole 20j will be collectively referred to as "central hole".

(connecting groove)
FIG. 2 is a view (viewed from the axial direction) showing the center hole of the carrier of the eccentric oscillation type reduction gear transmission 10. As shown in FIG. The first central hole 18j has a first connecting groove 18k for connecting the projecting shaft 40. As shown in FIG. The first connecting groove 18k is provided over the entire axial length of the first central hole 18j. The second central hole 20j has a second connecting groove 20k for connecting the protruding shaft 40. As shown in FIG. The second connecting groove 20k is provided over the entire axial length of the second central hole 20j. Hereinafter, the first connecting groove 18k and the second connecting groove 20k will be collectively referred to as "connecting groove". The connecting groove may be formed by a gear shaper. In this example, the connecting groove is a spline groove that includes multiple grooves.

The connecting groove of this embodiment includes a plurality of grooves 19m arranged around the center axis La. The number, shape, arrangement, etc. of the plurality of grooves 19m can be set by simulation or experiment according to the desired connection strength. The groove 19m of this embodiment is a groove that has a substantially rectangular cross section and extends in the axial direction. The plurality of grooves 19m may be arranged at regular intervals around the center axis La.

FIG. 2 shows the positional relationship between the first connecting groove 18k and the second connecting groove 20k when the first carrier 18 and the second carrier 20 are connected. The first connecting groove 18k of the first central hole 18j and the second connecting groove 20k of the second central hole 20j may have different shapes, but in this example they have the same shape. As shown in FIG. 2, the first connecting groove 18k and the second connecting groove 20k of this embodiment have the same groove shape phase when the first carrier 18 and the second carrier 20 are connected. I am doing it. That is, the uneven shape of the groove 19m of the first connecting groove 18k substantially overlaps with the uneven shape of the groove 19m of the second connecting groove 20k when viewed in the axial direction.

An example of the process of processing the first connecting groove 18k and the second connecting groove 20k will be described. First, the first carrier 18 and the second carrier 20 are connected. At this time, they may be positioned by positioning pins 18q, which will be described later, and connected by bolts 18p. With the first carrier 18 and the second carrier 20 connected, the first connecting groove 18k and the second connecting groove 20k are simultaneously processed by a gear shaper or the like. By processing in this way, the phases of these groove shapes can be matched. Since the phases of the respective groove shapes are aligned, the first connecting groove 18k and the second connecting groove 20k can be processed at the same time, and the number of processing steps can be reduced compared to the case where they are processed separately.

This processing step may be performed after the eccentric oscillating speed reducer 10 has been assembled to the stage where it does not have the projecting shaft 40, or after the first carrier 18 and the second carrier 20 are temporarily connected. may be done. In the latter case, the eccentric oscillating speed reducer 10 can be assembled after being disassembled after this processing step. In this case, since unnecessary load is hardly applied to the bearing or the like during machining, the accuracy of the bearing can be easily maintained.

(protruding shaft)
As shown in FIG. 1, the protruding shaft 40 fits into both the first central hole 18j and the second central hole 20j, and protrudes axially outward from at least the first central hole 18j. According to this configuration, the protruding shaft 40 fits into the central holes of both the first carrier 18 and the second carrier 20, so that the coupling between the protruding shaft 40 and the carriers is less than when only one of the carriers is fitted. Can improve strength. The protruding shaft 40 in FIG. 1 extends from the end face of the first carrier 18 on the non-input side to the non-input side. In this case, casing 22 can be fixed and rotation can be transmitted from projecting shaft 40 to a driven device (not shown). Also. The projecting shaft 40 can be fixed to transmit rotation from the casing 22 to the driven device.

(Connecting part)
The protruding shaft 40 is a cylindrical (columnar) member as a whole, and includes a first connecting portion 40b corresponding to the first connecting groove 18k, a second connecting portion 40c corresponding to the second connecting groove 20k, and a first connecting portion 40c corresponding to the second connecting groove 20k. It has an intermediate connecting portion 40e that connects the connecting portion 40b and the second connecting portion 40c. Hereinafter, the first connecting portion 40b, the second connecting portion 40c, and the intermediate connecting portion 40e will be referred to collectively as "connecting portions." Since the first connecting portion 40b, the second connecting portion 40c, and the intermediate connecting portion 40e can be processed continuously, the number of processing steps can be reduced compared to the case where they are processed separately.

The first connecting portion 40b, the second connecting portion 40c, and the intermediate connecting portion 40e may be formed discontinuously. Consists of 40 m of continuous grooves. In this case, since the first connecting portion 40b, the second connecting portion 40c and the intermediate connecting portion 40e can be processed simultaneously, the number of processing steps can be reduced as compared with the case of forming them separately. Here, since the peaks between the grooves 40m adjacent in the circumferential direction are fitted with the connecting grooves 19m of the carrier, the first connecting portion 40b, the second connecting portion 40c and the intermediate connecting portion 40e are continuous. It can also be said that it is composed of ridges that overlap. The groove 40m is not formed around the tip of the protruding shaft 40 (the portion connected to the driven member).

The outer diameter of the intermediate connecting portion 40e (the outermost diameter of the ridges) may be different from the outer diameter of the first connecting portion 40b and the second connecting portion 40c (the outermost diameter of the ridges). Then, the outer diameter of the intermediate connecting portion 40e is equal to the outer diameters of the first connecting portion 40b and the second connecting portion 40c. Since the outer shape of the intermediate connecting portion 40e can be processed at the same time as the outer shapes of the first connecting portion 40b and the second connecting portion 40c, the number of processing steps can be reduced as compared with the case where they are processed separately.

In this embodiment, the shortest distance Lm to the central hole 14h of the external gear 14 is the distance to the outermost circumference 40d (the outermost diameter of the crest) of the protruding shaft 40 in terms of the distance from the axis of the first carrier 18. greater than Ld. The outermost circumference 40d is the outermost circumference of the peaks of the first connecting portion 40b, the intermediate connecting portion 40e and the second connecting portion 40c. In this example, the axis of the first carrier 18 coincides with the center axis La of the internal gear 16 . Therefore, the shortest distance Lm is the distance from the center axis La to the nearest portion to the center hole 14h, and is the distance to the position on the anti-eccentric side of the center hole 14h. In this case, when the external gear 14 and the protruding shaft 40 rotate relative to each other, the external gear 14 and the protruding shaft 40 can maintain a non-contact state with each other, so smooth rotation can be achieved.

(Retaining mechanism)
If a strong force is applied between the protruding shaft 40 and the carrier, the protruding shaft 40 may come off from the carrier. Therefore, this embodiment has a retaining mechanism 40h that prevents the projecting shaft 40 from coming off from the first carrier 18 and the second carrier 20 (the first central hole 18j and the second central hole 20j). In this case, it becomes difficult for the projecting shaft 40 to come off from the carrier. The retaining mechanism 40h includes a retaining member 40p and a bolt 40q.

The retaining member 40p in FIG. 1 is a disk-shaped member having a bolt hole 40r axially penetrating in the center in the radial direction. The retaining member 40p has an outer diameter larger than the inner diameter of the central hole 20j. A tap hole 40s is provided in the end face of the protruding shaft 40 on the input side. The retaining member 40p is fixed to the projecting shaft 40 by screwing a bolt 40q into the tap hole 40s via the bolt hole 40r. With this configuration, even if force is applied to the protruding shaft 40 in the direction opposite to the input side, the retaining member 40p abuts against the input side end surface of the second carrier 20 to prevent the protruding shaft 40 from coming off the carrier. The shape of the retaining member 40p and the bolt 40q may be set according to desired retaining strength. Further, when the projecting shaft 40 attempts to come off to the input side, the retaining member 40p and the input gear 70 abut to prevent the projecting shaft 40 from coming off.

(shaft part)
The first carrier 18 and the second carrier 20 are connected via a shaft portion 18s. The shaft portion 18 s is provided at a position radially offset from the axis of the external gear 14 . The shaft portion 18 s in FIG. 1 is a portion extending axially from the first carrier 18 toward the second carrier 20 and is integrally formed with the first carrier 18 . The shaft portion 18s is inserted through a shaft hole 14p formed through the external gear 14 with a gap therebetween.

The shaft portion 18 s is fixed to the second carrier 20 with its distal end in contact with the end surface of the second carrier 20 on the opposite side to the input side. When the shaft portion 18s is fixed to the second carrier 20, it is positioned by a positioning pin 18q and fixed by a bolt 18p. The shaft portion 18 s functions as a connecting portion that contributes to the connection between the first carrier 18 and the second carrier 20 .

(casing)
The casing 22 has a hollow cylindrical shape as a whole, and the internal gear 16 is provided on the inner periphery thereof. A flange 22 f is provided on the outer peripheral portion of the casing 22 . The flange 22f is provided with through holes 22h and tap holes 22j spaced apart in the circumferential direction. These holes are used to connect casing 22 with external members or driven devices.

The casing 22 is provided with a recess 22m for housing the outer ring of the first main bearing 24 and a recess 22n for housing the outer ring of the second main bearing 26 . The casing 22 and the carrier are rotatable relative to each other via a first main bearing 24 and a second main bearing 26 .

(main bearing)
The main bearings 24 , 26 include a first main bearing 24 located between the first carrier 18 and casing 22 and a second main bearing 26 located between the second carrier 20 and casing 22 . The main bearings 24, 26 of this embodiment comprise a plurality of rolling elements 28 and a retainer (not shown). A plurality of rolling elements 28 are provided at intervals in the circumferential direction. The rolling element 28 of this embodiment is a sphere. The retainer holds the relative positions of the plurality of rolling elements 28 and rotatably supports the plurality of rolling elements 28 . The main bearings 24, 26 may be roller bearings or cross roller bearings.

The main bearings 24, 26 of this embodiment comprise an outer ring 30 having a rolling surface of the rolling element 28 and do not comprise an inner ring. The inner rolling surfaces of the main bearings 24,26 are provided on the outer peripheral surfaces of the carriers 18,20 instead of the inner rings. The outer ring 30 is fixed to the casing 22 by a fit such as a clearance fit, an interference fit, or an intermediate fit. An oil seal 22 s is provided between the first carrier 18 and the casing 22 . The oil seal 22s is arranged on the non-input side of the first main bearing 24 .

One of the first carrier 18 and the casing 22 functions as an output member that outputs rotational power to the driven device, and the other functions as a fixed member that is fixed to an external member for supporting the eccentric oscillation type reduction gear transmission 10. Function. In this embodiment, the output member is the first carrier 18 and the fixed member is the casing 22 . The casing 22 may be the output member and the first carrier 18 may be the fixed member.

The operation of the eccentric oscillation type reduction gear transmission 10 configured as described above will be described. When rotational power is transmitted from the driving device to the rotating shaft, the rotating power is distributed from the rotating shaft to the plurality of input gears 70, and each input gear 70 rotates in the same phase. When each input gear 70 rotates, the eccentric portion 12a of the crankshaft 12 rotates around the rotation center line passing through the crankshaft 12, and the external gear 14 oscillates due to the eccentric portion 12a. When the external gear 14 oscillates, the meshing positions of the external pin 17 of the external gear 14 and the internal gear 16 are sequentially displaced. As a result, each time the crankshaft 12 makes one rotation, one of the external gear 14 and the internal gear 16 is rotated by the difference between the number of teeth of the external gear 14 and the number of the external pins 17 of the internal gear 16. rotation occurs. In this embodiment, the external gear 14 rotates, and reduced rotation is output from the projecting shaft 40 via the first carrier 18 .

Exemplary embodiments of the present invention have been described above in detail. All of the above-described embodiments merely show specific examples for carrying out the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as changes, additions, and deletions of constituent elements can be made without departing from the spirit of the invention defined in the claims. It is possible. In the above-described embodiment, descriptions such as "of the embodiment", "in the embodiment", etc. are attached to the contents that allow such design changes. Changes are not unacceptable. In addition, the hatching attached to the cross section of the drawing does not limit the material of the hatched object.

Modifications will be described below. In the drawings and description of the modified example, the same reference numerals are given to the same or equivalent components and members as the embodiment. Explanations that overlap with the embodiment will be omitted as appropriate, and the explanation will focus on the configuration that is different from the embodiment.

[First modification]
In the description of the embodiment, an example of having a retaining mechanism 40h that prevents the protruding shaft 40 from coming off from the first carrier and the second carrier was shown, but the present invention is not limited to this. It is not essential to have a retaining mechanism. FIG. 3 is a side cross-sectional view showing an eccentric oscillation type reduction gear transmission 10 of a first modified example, and corresponds to FIG. The eccentric oscillating speed reducer 10 of FIG. 3 differs from the embodiment in that it does not have a retainer mechanism 40h, and the rest of the configuration is the same.

The first modified example has the same functions and effects as the embodiment. In addition, since the first modified example does not have the retainer mechanism 40h, the number of parts is reduced, and the machining of the projecting shaft 40 is partially eliminated, thereby reducing the number of machining steps. This facilitates the manufacture of the eccentric oscillating speed reducer 10 and reduces the manufacturing cost.

[Second modification]
In the description of the embodiments, an example in which the central hole has a connecting groove has been shown, but the present invention is not limited to this. It is not essential that the central hole have a connecting groove. FIG. 4 is a side cross-sectional view showing an eccentric oscillating reduction gear transmission 10 of a second modification, and corresponds to FIG. The eccentric oscillating type reduction gear transmission 10 of FIG. 4 differs from the embodiment in that it does not have a retainer mechanism 40h, a connecting groove in the central hole, and a connecting portion of the protruding shaft 40. The configuration is similar. The projecting shaft 40 may be fixed to the central hole by press fitting, shrink fitting, adhesion, or the like.

The second modified example has the same actions and effects as the embodiment. In addition, the second modified example does not have the retaining mechanism 40h, the connecting groove of the central hole, and the connecting portion having the groove (mountain) of the protruding shaft 40, thereby reducing the number of parts and Since the shape of 40 and the central hole is simplified, the number of processing steps is reduced. This facilitates the manufacture of the eccentric oscillating speed reducer 10 and further reduces the manufacturing cost.

[Third Modification]
Although the example in which the outer diameter of the projecting shaft 40 is constant has been shown in the description of the embodiment, the present invention is not limited to this. It is not essential that the outer diameter of the projecting shaft 40 is constant. FIG. 5 is a side cross-sectional view showing an eccentric oscillating reduction gear transmission 10 of a third modification, and corresponds to FIG. The eccentric oscillating speed reducer 10 of FIG. 5 differs from the embodiment in that the projecting shaft 40 has a stepped portion 40k, and the rest of the configuration is the same. In this modified example, the input side of the stepped portion 40k provided on the protruding shaft 40 is brought into contact with the first carrier 18 to prevent the protruding shaft 40 from coming off to the input side. The diameter of the outer circumference 40j of the protruding portion protruding from the first central hole 18j of the protruding shaft 40 is larger than the diameters of the outermost circumferences 40d of the first connecting portion 40b, the intermediate connecting portion 40e and the second connecting portion 40c.

In this modification, the shortest distance Lm to the central hole 14h of the external gear 14 in the distance from the axis of the first carrier 18 is the first connecting portion 40b, the intermediate connecting portion 40e, and the second connecting portion of the projecting shaft 40. It is larger than the distance Ld to the outermost periphery 40d of the portion 40c. That is, in this modification, "the distance to the outermost circumference of the projecting shaft" is exemplified by the distance Ld to the outermost circumference 40d of the first connecting portion 40b, the intermediate connecting portion 40e, and the second connecting portion 40c.

[Other Modifications]
Although the second central hole 20j is a through hole in the description of the embodiment, the present invention is not limited to this. The second central hole 20j may be a non-through hole whose input side is closed. For example, the second central hole 20j may be a recess axially recessed from the non-input side of the second carrier 20 .

Although the example in which the grooves 19m are arranged at equal intervals in the circumferential direction has been described in the description of the embodiment, the present invention is not limited to this. The grooves 19m may be arranged at uneven intervals. For example, the central hole may have, in the circumferential direction, an uneven portion in which several grooves 19m are continuously provided and a non- uneven portion in which the grooves 19m are not provided and extend smoothly. In the first central hole 18j, uneven portions and non- uneven portions may be alternately arranged in the circumferential direction. In this case, the connecting portion of the protruding shaft is also provided with an uneven portion corresponding to the central hole. In addition, in the embodiment, the protrusion shaft 40 is provided with the same number of ridges as the grooves 19m, but the present invention is not limited to this, and some of the ridges may be omitted.

In the description of the embodiments, an example in which the connecting groove is a spline groove including a plurality of grooves was shown, but the present invention is not limited to this. The connecting groove may include one or more known grooves. For example, the connecting grooves may be key grooves, D-cuts, or knurled grooves.

In the description of the embodiment, an example in which the retaining member 40p is fixed to the protruding shaft 40 with the bolt 40q has been shown, but the present invention is not limited to this. The retaining member 40p may be fixed to the protruding shaft 40 by a fastener other than the bolt 40q. Also, the retaining member may be a C-ring engaged with a groove provided around the end of the projecting shaft 40 .

Although the number of crankshafts 12 and input gears 70 is three in the description of the embodiment, the present invention is not limited to this. The number of crankshafts 12 and input gears 70 may be one, two, four or more.

Although the description of the embodiment has shown an example in which two external gears 14 are provided, the present invention is not limited to this. Three or more external gears 14 may be provided. For example, the crankshaft may be provided with three eccentric portions 12a that are out of phase with each other by 120°, and may be provided with three external gears 14 that are oscillated by the three eccentric portions 12a. Also, the number of external gears 14 may be one.

Although the second main bearing 26 and the first main bearing 24 have no inner ring in the description of the embodiment, the present invention is not limited to this. One or both of the second main bearing 26 and the first main bearing 24 may be bearings having inner rings.

Each of the modifications described above has the same functions and effects as the above-described embodiment.

Any combination of the above-described embodiments and modifications is also useful as embodiments of the present invention. A new embodiment resulting from the combination has the effects of each of the combined embodiments and modifications.

Reference Signs List 10 Eccentric oscillating type speed reducer 12 Crankshaft 14 External gear 16 Internal gear 18 First carrier 18j First central hole 18k First Connection groove 19m Groove 20 Second carrier 20j Second central hole 20k Second connection groove 40 Protruding shaft 40b First connection part 40c Second Connecting portion 40d Outer diameter 40e Intermediate connecting portion 40h Retaining mechanism 70 Input gear.

Claims (7)

a casing provided with an internal gear; an external gear; a crankshaft arranged offset from the axial center of the internal gear to oscillate the external gear; An eccentric oscillating type reduction gear including a first carrier arranged and synchronized with the rotation of the external gear, and a second carrier arranged on the other axial side of the external gear and connected to the first carrier There is
a first bearing disposed between the first carrier and the casing;
a second bearing disposed between the second carrier and the casing;
the first carrier on which the first bearing is arranged has a first central hole in the center in the radial direction;
the second carrier on which the second bearing is arranged has a second central hole in the center in the radial direction;
having a protruding shaft that fits in both the first central hole and the second central hole and protrudes axially outward from at least the first central hole;
Rotation is transmitted from the projecting shaft to the driven device by connecting the projecting shaft to the driven device, or the first carrier and the first carrier are connected by fixing the projecting shaft to the driven device. 2 carriers are non-rotatably fixed to the driven device. The first central hole has a first connecting groove for connecting the protruding shaft, the second central hole has a second connecting groove for connecting the protruding shaft, and the first carrier and the 2. The eccentric oscillating type reduction gear transmission according to claim 1, wherein the phases of the first connecting groove and the second connecting groove match when the second carrier is connected. The projecting shaft includes a first connecting portion corresponding to the first connecting groove, a second connecting portion corresponding to the second connecting groove, and an intermediate connecting portion connecting the first connecting portion and the second connecting portion. 3. The eccentric oscillating type reduction gear transmission according to claim 2, characterized by comprising: 4. The eccentric oscillating type reduction gear transmission according to claim 3, wherein the first connecting portion, the second connecting portion and the intermediate connecting portion are composed of continuous mountain portions. 5. The eccentric oscillating type reduction gear transmission according to claim 1, wherein no bearing is arranged in the projecting portion projecting axially outward from the first central hole of the projecting shaft. 6. Any one of claims 1 to 5, wherein the shortest distance to the central hole of the external gear is greater than the distance to the outermost periphery of the protruding shaft in the distance from the axis of the first carrier. The eccentric oscillating type speed reducer as described. a retaining mechanism for preventing the projecting shaft from coming off from the first and second central holes to the projecting side of the projecting shaft ; 7. The eccentric oscillating type reduction gear transmission according to any one of claims 1 to 6, wherein the .

Images