JP2020063808A - Eccentric oscillation type speed reduction device - Google Patents

Abstract

To provide an eccentric oscillation type speed reduction device that can improve connection strength between a protruding shaft and a carrier.SOLUTION: An eccentric oscillation type speed reduction device 10 comprises: an internal gear 16; an external gear 14; a crankshaft 12 arranged so as to be offset from an axis of the internal gear 16, and for rocking the external gear 14; a first carrier 18 arranged on one side in an axial direction of the external gear 14, and to be synchronized with rotation of the external gear 14; and a second carrier 20 arranged on another side in the axial direction of the external gear 14, and connected to the first carrier 18. The first carrier 18 comprises a first center hole 18j at a center in a radial direction. The second carrier 20 comprises a second center hole 20j at the center in the radial direction. The eccentric oscillation type speed reduction device comprises a protruding shaft 40 fitted in both the first center hole 18j and the second center hole 20j, and protruding outward in the axial direction from at least the first center hole 18j.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an eccentric oscillating speed reducer.

  Patent Document 1 describes an eccentric oscillating gear device. The gear device described in Patent Document 1 includes an outer cylinder and a carrier, and fixes the outer cylinder to transmit rotation from the carrier to a counterpart member.

JP, 2017-155772, A

In the gear device described in Patent Document 1, the output shaft portion is press-fitted and fixed in the center hole of the carrier, and the rotation is transmitted to the 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 by the present inventor, it has been found that in this configuration, the transmission torque to the output shaft portion is not sufficient because the coupling strength between the carrier and the output shaft portion is low.
From these, the present inventor has recognized that the gear device described in Patent Document 1 has a problem to be improved from the viewpoint of improving the coupling strength between the carrier and the output shaft portion.

  The present invention has been made in view of the above problems, and an object thereof is to provide an eccentric oscillating speed reducer capable of improving the coupling strength between a protruding shaft and a carrier.

  In order to solve the above problems, an eccentric oscillating reduction gear according to an aspect of the present invention oscillates an internal gear, an external gear, and an external gear that is arranged offset from the axis of the internal gear. And a first carrier arranged on one axial side of the external gear 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. And an eccentric oscillating speed reducer. The first carrier has a first central hole in the radial center, the second carrier has a second central hole in the radial center, and fits into both the first central hole and the second central hole, It has a projecting shaft projecting axially outward from at least the first central hole.

  It should be noted that any combination of the above constituent elements, and those in which the constituent elements and expressions of the present invention are mutually replaced among methods, systems, etc. are also effective as an aspect of the present invention.

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

It is a side sectional view showing an eccentric rocking type reduction gear transmission of an embodiment. It is a figure which shows the center hole of the carrier of the eccentric oscillating type reduction gear transmission of FIG. It is a side sectional view showing an eccentric rocking | velocity-type speed reducer of a 1st modification. It is a side sectional view showing an eccentric rocking | velocity reduction gear of 2nd modification. It is a side surface sectional view showing the eccentric rocking | fluctuation type reduction gear of a 3rd modification.

Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. In the embodiments and the modified examples, the same or equivalent constituent elements and members are designated by the same reference numerals, and the duplicated description will be omitted as appropriate. Further, the dimensions of the members in each drawing are enlarged or reduced as appropriate for easy understanding. Moreover, in each drawing, some of the members that are not important for explaining the embodiment are omitted.
Also, terms including ordinal numbers such as first and second are used to describe various constituent elements, but this term is used only for the purpose of distinguishing one constituent element from another constituent element. The constituent elements are not limited by.

[Embodiment]
Hereinafter, the configuration of the eccentric rocking type reduction gear transmission 10 according to the embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a side sectional view showing an eccentric rocking type reduction gear transmission 10 of an embodiment. The eccentric oscillating speed reducer 10 of the present embodiment is a so-called distribution type eccentric oscillating speed reducer. This eccentric oscillating reduction gear 10 causes one of the internal gear and the external gear to rotate by oscillating an external gear that meshes with the internal gear, and the generated rotational component is transmitted from the output member. It is configured to output to the driving device.

  The eccentric rocking type reduction gear transmission 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 the protruding shaft 40. Hereinafter, the direction along the central axis La of the internal gear 16 is referred to as “axial direction”, and the circumferential direction and the radial direction of a circle centered on the central axis La are referred to as “circumferential direction” and “radial direction”, respectively. To do. Further, hereinafter, for convenience, one side (the right side in the drawing) in the axial direction is referred to as an input side, and the other side (the left side in the drawing) is referred to as a non-input side.

(Input gear)
Three input gears 70 are arranged around the central axis La of the internal gear 16. The three input gears 70 are arranged at positions offset from the central axis La at equal intervals of 120 °. In FIG. 1, only one input gear 70 is shown. Three crankshafts 12 are provided corresponding to the three input gears 70. The crankshaft 12 is inserted through the central portion 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 rotatably provided integrally with the input gear 70. The three input gears 70 mesh with the outer teeth of a rotary shaft (not shown) provided on the central axis La. Rotational power is transmitted to the rotation shaft from a drive device (not shown), and the rotation of the rotation shaft causes the input gear 70 to rotate integrally with the crankshaft 12. The drive device is, for example, a motor, a gear motor, an engine, or the like.

(Crankshaft)
The crankshaft 12 of the present embodiment is an eccentric body shaft having a plurality of eccentric portions 12a for swinging the external gear 14. The shaft center of the eccentric portion 12a 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 the 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 non-input side supported by the first carrier 18 via a crankshaft bearing 34. The non-input side crankshaft bearing 34 is fitted and supported in the crankshaft hole 18h of the first carrier 18, and the input side crankshaft bearing 34 is fitted and supported in the crankshaft hole 20h of the second carrier 20. That is, the crankshaft 12 is rotatably supported by the first carrier 18 and the second carrier 20. The crankshaft bearing 34 is a roller bearing having a cylindrical rolling element in this example, although its structure is not particularly limited.

(Internal gear)
The internal gear 16 meshes with the external gear 14. The internal gear 16 of the present embodiment has an internal gear main body 16a integrated with the casing 22 and external pins arranged in a plurality of pin grooves formed in the internal gear main body 16a at intervals in the circumferential direction. And 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 an inner tooth of the internal gear 16. The number of outer pins 17 of the internal gear 16 (the number of internal teeth) is slightly larger than the number of external teeth of the external gear 14 (in this example, only 1).

(External gear)
The external gear 14 is provided individually 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 roller 32. The external gear 14 is provided with three shaft holes 14p and three rocking holes 14j at predetermined intervals at positions offset from the axis thereof.

  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 therein. The shaft hole 14p is formed larger than the outer diameter of the shaft portion 18s and has a size that does not contact 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 oscillating 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 oscillating 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 movement of the eccentric portion 12a to the swing hole 14j.

  The external gear 14 is provided with a central hole 14h through which a protrusion shaft 40 described later passes. The central hole 14h is a hole provided at the center of the external gear 14 in the radial direction, is formed larger than the outermost diameter of the protruding shaft 40, and has a size that does not contact the protruding shaft 40. The shape of the central hole 14h is not limited, but the central hole 14h in this example is circular.

  Corrugated teeth are formed on the outer periphery of the external gear 14, and the external gear 14 oscillates in a plane with the central axis as the normal line by moving while contacting the internal gear 16. You can do it.

(Carrier)
The carriers 18, 20 are arranged on the axial side of the external gear 14. The carriers 18 and 20 include a first carrier 18 arranged on the side opposite to the input side of the external gear 14 and a second carrier 20 arranged on the input side of the external gear 14. Be done. Hereinafter, the first carrier 18 and the second carrier 20 are collectively referred to as “carrier”. The carrier is rotatably supported by the casing 22 via a first main bearing 24 and a second main bearing 26. The carrier has a hollow disk shape or a cylindrical shape as a whole. The carrier rotatably supports the crankshaft 12 via a crankshaft bearing 34.

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

(Connecting groove)
FIG. 2 is a diagram (a diagram viewed from the axial direction) showing the center hole of the carrier of the eccentric rocking type reduction gear transmission 10. The first central hole 18j has a first connecting groove 18k for connecting the protruding shaft 40. The first connection 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. The second connection 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 are collectively referred to as "connecting groove". The connection groove may be formed by a gear shaper. In this example, the connecting groove is a spline groove including a plurality of grooves.

  The connection groove of the present embodiment includes a plurality of grooves 19m arranged around the central 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 the present embodiment is a groove having a substantially rectangular cross section and extending in the axial direction. The plurality of grooves 19m may be arranged at equal intervals around the central 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 they have the same shape in this example. As shown in FIG. 2, the first connecting groove 18k and the second connecting groove 20k of the present 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 connection groove 18k and the uneven shape of the groove 19m of the second connection groove 20k substantially overlap with each other when viewed in the axial direction.

  An example of a 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, the positioning pin 18q described later may be used for positioning and the bolt 18p may be used for connection. In a state where the first carrier 18 and the second carrier 20 are connected, the first connection groove 18k and the second connection 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 as compared with the case of processing them separately.

  It should be noted that this processing step may be performed in a state where the eccentric rocking type reduction gear transmission 10 is assembled up to a stage where the protruding shaft 40 is not provided, or in a state where the first carrier 18 and the second carrier 20 are temporarily connected. May be done. In the latter case, the eccentric rocking type speed reducer 10 can be assembled after being disassembled after this processing step. In this case, since an unnecessary load is hardly applied to the bearing or the like during processing, the accuracy of the bearing can be easily maintained.

(Protruding shaft)
As shown in FIG. 1, the projecting shaft 40 is fitted in both the first central hole 18j and the second central hole 20j, and projects from at least the first central hole 18j outward in the axial direction. According to this structure, the protruding shaft 40 fits into the central holes of both the first carrier 18 and the second carrier 20, so that the protruding shaft 40 and the carrier are connected as compared with the case where only one fits. Strength can be improved. The protruding shaft 40 in FIG. 1 extends from the end surface on the non-input side of the first carrier 18 to the non-input side. In this case, the casing 22 can be fixed, and the rotation can be transmitted from the protruding shaft 40 to the driven device (not shown). Also. By fixing the protruding shaft 40, the rotation can be transmitted from the casing 22 to the driven device.

(Connecting part)
The protruding shaft 40 is a cylindrical (cylindrical) 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. It has the connection part 40b and the intermediate connection part 40e which connects the 2nd connection part 40c. Hereinafter, the first connecting portion 40b, the second connecting portion 40c, and the intermediate connecting portion 40e are collectively referred to as "connecting portion". Since the first connecting portion 40b, the second connecting portion 40c, and the intermediate connecting portion 40e can be continuously processed, the number of processing steps can be reduced as compared with the case where they are separately processed.

  The first connecting portion 40b, the second connecting portion 40c, and the intermediate connecting portion 40e may be formed discontinuously, but the first connecting portion 40b, the second connecting portion 40c, and the intermediate connecting portion 40e of the present embodiment are It is composed of continuous grooves 40m. In this case, since the first connecting portion 40b, the second connecting portion 40c, and the intermediate connecting portion 40e can be processed at the same time, the number of processing steps can be reduced as compared with the case where they are formed separately. Here, since the mountain portion between the grooves 40m adjacent to each other in the circumferential direction fits with the connecting groove 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 a mountain portion. 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 mountain portion) may be different from the outer diameter of the first connecting portion 40b and the second connecting portion 40c (the outermost diameter of the mountain portion), but the present embodiment. Then, the outer diameter of the intermediate connecting portion 40e is equal to the outer diameter 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 the present embodiment, in the distance from the axis of the first carrier 18, the shortest distance Lm to the central hole 14h of the external gear 14 is the distance to the outermost circumference 40d (outermost diameter of the mountain portion) of the protruding shaft 40. 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 central axis La of the internal gear 16. Therefore, the shortest distance Lm is the distance from the central axis La to the closest portion to the central hole 14h, and is the distance to the position on the anti-eccentric side of the central hole 14h. In this case, when the external gear 14 and the projecting shaft 40 rotate relative to each other, the external gear 14 and the projecting shaft 40 can be kept in non-contact with each other, so that smooth rotation can be realized.

(Prevention mechanism)
When a strong force is applied between the protruding shaft 40 and the carrier, the protruding shaft 40 may come off from the carrier. Therefore, the present embodiment has a retaining mechanism 40h that prevents the protruding 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, the protruding shaft 40 is less likely to come off 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 penetrating in the axial direction at the center in the radial direction. The outer diameter of the retaining member 40p is larger than the inner diameter of the central hole 20j. A tap hole 40s is provided on the end surface of the protruding shaft 40 on the input side. The retaining member 40p is fixed to the protruding shaft 40 by screwing a bolt 40q into the tap hole 40s via the bolt hole 40r. With this configuration, even if a force is applied to the protruding shaft 40 on the side opposite to the input side, the retaining member 40p abuts on the input-side end surface of the second carrier 20 and prevents the protruding shaft 40 from coming off the carrier. The shapes of the retaining member 40p and the bolt 40q may be set according to desired retaining strength. Further, when the protruding shaft 40 is about to come out to the input side, the coming-off preventing member 40p and the input gear 70 come into contact with each other, so that the protruding shaft 40 is prevented from coming off.

(Shaft part)
The first carrier 18 and the second carrier 20 are connected via the shaft portion 18s. The shaft portion 18s is provided at a position radially offset from the axis of the external gear 14. The shaft portion 18s of FIG. 1 is a portion that extends in the axial direction 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 with a gap in a shaft hole 14p formed through the external gear 14.

  The tip portion of the shaft portion 18s is in contact with the end surface of the second carrier 20 on the side opposite to the input side, and is fixed to the second carrier 20. When the shaft portion 18s is fixed to the second carrier 20, the shaft portion 18s is positioned by the positioning pin 18q and fixed by the bolt 18p. The shaft portion 18s 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 peripheral portion thereof. A flange 22f is provided on the outer peripheral portion of the casing 22. The flange 22f is provided with a through hole 22h and a tap hole 22j that are separated from each other in the circumferential direction. These holes are used to connect the casing 22 to an external member or a driven device.

  The casing 22 is provided with a recess 22m for accommodating the outer ring of the first main bearing 24 and a recess 22n for accommodating the outer ring of the second main bearing 26. The casing 22 and the carrier are configured to be 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 arranged between the first carrier 18 and the casing 22, and a second main bearing 26 arranged between the second carrier 20 and the casing 22. The main bearings 24 and 26 of the present embodiment include a plurality of rolling elements 28 and a retainer (not shown). The 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 and 26 may be roller bearings or cross roller bearings.

  The main bearings 24, 26 of the present embodiment include the outer ring 30 having the rolling surface of the rolling element 28 and no 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 ring. 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 22s 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 serves as a fixed member that is fixed to an external member for supporting the eccentric oscillating reduction device 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 oscillating reduction gear transmission 10 configured as described above will be described. When the rotary power is transmitted from the drive device to the rotary shaft, the rotary power is distributed from the rotary shaft to the plurality of input gears 70, and the respective input gears 70 rotate 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 eccentric portion 12a causes the external gear 14 to swing. When the external gear 14 swings, the meshing positions of the external pin 14 of the external gear 14 and the internal gear 16 are sequentially displaced. As a result, each time the crankshaft 12 makes one revolution, one of the external gear 14 and the internal gear 16 is equivalent to the difference between the number of teeth of the external gear 14 and the number of external pins 17 of the internal gear 16. Rotation occurs. In the present embodiment, the external gear 14 rotates, and the decelerated rotation is output from the protruding shaft 40 via the first carrier 18.

  The example of the embodiment of the present invention has been described above in detail. Each of the above-described embodiments is merely a specific example 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 modification of components, addition, deletion, etc. are possible within a range not departing from the idea of the invention defined in the claims. It is possible. In the above-described embodiment, the contents such as the design change are described with the notations such as “of the embodiment” and “in the embodiment”, but the contents without such notation are designed. Change is not unacceptable. Further, the hatching attached to the cross section of the drawing does not limit the material to which the hatching is attached.

  Hereinafter, modified examples will be described. In the drawings and description of the modified example, the same or equivalent components and members as those of the embodiment are designated by the same reference numerals. Descriptions that overlap with the embodiments will be omitted as appropriate, and configurations different from the embodiments will be mainly described.

[First Modification]
In the description of the embodiment, the example in which the protruding shaft 40 has the retaining mechanism 40h that prevents the protruding shaft 40 from coming off from the first carrier and the second carrier is shown, but the present invention is not limited to this. It is not essential to have a retaining mechanism. FIG. 3 is a side sectional view showing an eccentric rocking type reduction gear transmission 10 of a first modified example, and corresponds to FIG. 1. The eccentric oscillating reduction gear transmission 10 of FIG. 3 is different from the embodiment in that it does not have a retaining mechanism 40h, and other configurations are the same.

  The first modified example has the same actions and effects as the embodiment. In addition, in the first modified example, since the retaining mechanism 40h is not provided, the number of parts is reduced, and since the protrusion shaft 40 is not partially processed, the processing man-hour is reduced. This facilitates the manufacture of the eccentric rocking type speed reducer 10 and reduces the manufacturing cost.

[Second Modification]
In the description of the embodiment, the example in which the central hole has the connecting groove is 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 sectional view showing an eccentric rocking type reduction gear transmission 10 of a second modified example, and corresponds to FIG. 1. The eccentric oscillating speed reducer 10 of FIG. 4 differs from the embodiment in that it does not have a retaining mechanism 40h, a connecting groove of the central hole, and a connecting portion of the projecting shaft 40, and other parts. The configuration is similar. The protruding 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 operations and effects as the embodiment. In addition, the second modification does not include the retaining mechanism 40h, the connecting groove of the central hole, and the connecting portion having the groove (mountain portion) of the protruding shaft 40, so that the number of parts is reduced and the protruding shaft is reduced. Since the shapes of 40 and the central hole are simplified, the number of processing steps is reduced. This facilitates the manufacture of the eccentric rocking type speed reducer 10 and further reduces the manufacturing cost.

[Third Modification]
In the description of the embodiment, an example in which the outer diameter of the protruding shaft 40 is constant has been shown, but the present invention is not limited to this. It is not essential that the outer diameter of the protruding shaft 40 be constant. FIG. 5 is a side sectional view showing an eccentric rocking type reduction gear transmission 10 of a third modified example, and corresponds to FIG. 1. The eccentric oscillating reduction gear transmission 10 of FIG. 5 differs from the embodiment in that the protruding shaft 40 has a step portion 40k, and other configurations are the same. In this modification, the input side of the step 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 projecting portion of the projecting shaft 40 projecting from the first central hole 18j is larger than the diameter of the outermost circumference 40d of the first connecting portion 40b, the intermediate connecting portion 40e, and the second connecting portion 40c.

  In this modification, in the distance from the axis of the first carrier 18, the shortest distance Lm to the central hole 14h of the external gear 14 is the first connecting portion 40b, the intermediate connecting portion 40e, and the second connecting portion 40e of the protruding shaft 40. It is larger than the distance Ld to the outermost periphery 40d of the portion 40c. That is, in the present modification, the "distance to the outermost circumference of the protruding 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]
In the description of the embodiment, an example in which the second central hole 20j is a through hole is shown, but 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 concave portion that is recessed in the axial direction from the non-input side of the second carrier 20.

  In the description of the embodiment, an example in which the grooves 19m are arranged at equal intervals in the circumferential direction has been shown, but the present invention is not limited to this. The grooves 19m may be arranged at unequal intervals. For example, the central hole may have a convex / concave portion in which several grooves 19m are continuously provided in the circumferential direction, and a non-concave / convex portion in which the groove 19m is not provided and smoothly extends. In the first central hole 18j, convex and concave portions and non-concave and convex 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. Further, in the embodiment, the protrusion shaft 40 has the same number of peaks as the grooves 19m, but the present invention is not limited to this, and some peaks may be omitted.

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

  In the description of the embodiment, the example in which the retaining member 40p is fixed to the protruding shaft 40 by 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. Further, the retaining member may be a C ring that engages with a groove provided around the outer periphery of the end of the protruding shaft 40.

  Although the number of the crankshaft 12 and the number of the input gears 70 are 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 1, 2 or 4 or more.

  In the description of the embodiment, an example in which two external gears 14 are provided has been shown, but 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 each having a phase difference of 120 °, and three external gears 14 that are swung by the three eccentric portions 12a. Further, the external gear 14 may be one.

  In the description of the embodiment, the example in which the second main bearing 26 and the first main bearing 24 have no inner ring has been shown, but 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 a bearing having an inner ring.

  The above-described modified examples have the same operations and effects as the above-described embodiment.

  Any combination of the above-described embodiment and modifications is also useful as an embodiment of the present invention. The new embodiment generated by the combination has the effects of the respective combined embodiments and modifications.

  10 ... Eccentric oscillating speed reducer, 12 ... crankshaft, 14 ... external gear, 16 ... internal gear, 18 ... first carrier, 18j ... first central hole, 18k ... 1st Connection groove, 19m .. groove, 20 .. second carrier, 20j .. second central hole, 20k .. second connecting groove, 40 .. protruding shaft, 40b .. first connecting portion, 40c .. second Connection part, 40d ... Outer diameter, 40e ... Intermediate connection part, 40h ... Detachment prevention mechanism, 70 ... Input gear.

Claims (7)

An internal gear, an external gear, a crankshaft that is arranged offset from the axis of the internal gear to oscillate the external gear, and the external gear that is arranged on one axial side of the external gear. An eccentric oscillating speed reducer comprising a first carrier synchronized with rotation of a gear and a second carrier arranged on the other axial side of the external gear and connected to the first carrier,
The first carrier has a first central hole in the radial center,
The second carrier has a second central hole in the radial center,
An eccentric oscillating reduction gear transmission characterized in that it has a protruding shaft that is fitted in both the first central hole and the second central hole and projects at least axially outward from the first central hole.   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 first carrier. The eccentric oscillating speed reducer according to claim 1, wherein the first connecting groove and the second connecting groove are in phase with each other when the second carrier is connected.   The protrusion 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. The eccentric oscillating speed reducer according to claim 2, further comprising:   The eccentric oscillating speed reducer according to claim 3, wherein the first connecting portion, the second connecting portion, and the intermediate connecting portion are formed by continuous mountain portions.   The eccentric oscillating speed reducer according to claim 3 or 4, wherein an outer diameter of the intermediate connecting portion is equal to an outer diameter of the first connecting portion and the second connecting portion.   The distance from the axial center of the first carrier, the shortest distance to the central hole of the external gear is greater than the distance to the outermost circumference of the protruding shaft. The eccentric rocking type reduction gear described.   The eccentric oscillating speed reducer according to any one of claims 1 to 6, further comprising a retaining mechanism that prevents the protruding shaft from coming off from the first central hole and the second central hole.

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