reducer

Abstract

To provide a speed reducer capable of suppressing the unstable behavior of an internal tooth pin during actuation.SOLUTION: A speed reducer comprises an outer cylinder member, an inner tooth pin 20, a plurality of rocking gears, and a carrier block. The outer cylinder member has a plurality of pin grooves 18 on an inner peripheral surface. The inner tooth pin 20 is rotatably disposed in each pin groove 18 of the outer cylinder member. The rocking gear has external teeth 15Aa and 15Ba with a smaller number of teeth than the number of grooves of the internal tooth pin 20, and rocks and rotates while engaging with the internal tooth pin 20 with the external teeth 15Aa and 15Ba. The carrier block is linked to the rocking gear so as to permit the relative rocking rotation of the rocking gear and regulates the relative self-rotation of the rocking gear. Between outer peripheral edge portions of the adjacent rocking gears, a displacement regulating member 31 is disposed, which regulates the displacement of the internal tooth pin to the inner side in a radial direction of the outer cylinder member.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a reducer that reduces the rotation speed of a rotary drive source. [Background technology]

[0002] BACKGROUND ART In rotating devices such as industrial robots and machine tools, reducers are used to reduce the rotation speed of a rotary drive source (see, for example, Patent Document 1).

[0003] The reducer described in Patent Document 1 includes an outer cylindrical member that also serves as a casing, a carrier block rotatably supported within the outer cylindrical member, multiple crankshafts rotatably supported on the outer peripheral edge of the carrier block, two oscillating gears that oscillate (orbit) in response to rotation of the eccentric portions of the multiple crankshafts, multiple internally toothed pins arranged in an area within the outer cylindrical member facing the outer peripheral surfaces of the two oscillating gears, and an input rotor that inputs rotational power to the multiple crankshafts. In this reducer, the input rotor is connected to a rotary drive source such as a motor, and the carrier block is coupled to a driven body. Each crankshaft is provided with two eccentric portions for oscillating (orbiting) the two oscillating gears in different phases (e.g., phases shifted by 180°).

[0004] A plurality of axially extending pin grooves are formed at predetermined intervals in the circumferential direction in the region of the inner peripheral surface of the outer cylindrical member facing the outer peripheral surfaces of the two oscillating gears. The plurality of internally toothed pins are rotatably arranged in each pin groove. External teeth are formed on the outer peripheral surfaces of each of the two oscillating gears, with the number of teeth being fewer than the number of internally toothed pins. When the two oscillating gears rotate (orbitally rotate) together with the eccentric portion of the crankshaft, each external tooth engages with the internally toothed pin during one oscillating rotation, receiving a reaction force from the internally toothed pin, and rotating (rotating) a predetermined pitch in the direction opposite to the oscillating rotation direction. At this time, the rotation (rotation) of the two oscillating gears is transmitted to the carrier block via the plurality of crankshafts. As a result, the rotation transmitted from the input rotor to the crankshaft and the oscillating gears is reduced at a predetermined reduction ratio and output to the carrier block. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-210843 Summary of the Invention [Problem to be solved by the invention]

[0006] In the reducer described in Patent Document 1, the depth of meshing between the external teeth and the internal pins changes depending on the oscillating rotation position of the oscillating gear, and depending on the oscillating rotation position, some of the internal pins may not receive pressing force from the external teeth. This phenomenon is particularly likely to occur when the number of external teeth of the oscillating gear is made two or more less than the number of internal pins in order to increase the output rotation speed of the reducer. In this case, there is a concern that the internal pins may separate from the pin grooves, causing unstable operation of the reducer.

[0007] The present invention provides a reducer that can suppress unstable behavior of the internal pin during operation. [Means for solving the problem]

[0008] A reducer according to one embodiment of the present invention comprises an outer tube member having a plurality of pin grooves on its inner surface, internally toothed pins rotatably arranged in each of the pin grooves of the outer tube member, a plurality of oscillating gears having external teeth with a number of teeth fewer than the number of the internally toothed pins, which rotate in an oscillating manner while meshing with the internally toothed pins with their external teeth, and a carrier block rotatably supported on the outer tube member, which allows relative oscillating rotation of the oscillating gears and is linked to the oscillating gears so as to regulate the relative rotation of the oscillating gears, and between the outer peripheral edges of adjacent oscillating gears is arranged annular displacement regulating members which regulate displacement of the internally toothed pins radially inward of the outer tube member.

[0009] The width of the displacement restriction member in the axial direction of the outer cylindrical member may be set to be narrower than the width between the outer peripheral edges of adjacent oscillating gears.

[0010] Adjacent oscillating gears may be provided on their inner peripheral edges with bosses that abut against each other in the axial direction of the outer cylindrical member.

[0011] Another aspect of the reducer of the present invention comprises an outer tube member having a plurality of pin grooves on its inner surface, internally toothed pins rotatably arranged in each of the pin grooves of the outer tube member, an oscillating gear having external teeth with a number of teeth fewer than the number of the internally toothed pins and which rotates in an oscillating manner while meshing with the internally toothed pins with its external teeth, and a carrier block rotatably supported on the outer tube member, allowing relative oscillating rotation of the oscillating gear and linked to the oscillating gear so as to regulate the relative rotation of the oscillating gear, wherein the carrier block has an adjacent arrangement portion arranged adjacent to the axial outside of the oscillating gear, the internally toothed pins are formed with an axial length that protrudes axially outward more than the oscillating gear, and the adjacent arrangement portion is provided with an annular displacement regulating portion that axially laps the end of the internally toothed pin at a position radially inward of the outer tube member than the internally toothed pins.

[0012] A reducer according to yet another aspect of the present invention comprises an outer tube member having a plurality of pin grooves on its inner surface, internally toothed pins rotatably arranged in each of the pin grooves of the outer tube member, an oscillating gear having external teeth with a number of teeth fewer than the number of the internally toothed pins and which rotates in an oscillating manner while meshing with the internally toothed pins with its external teeth, a carrier block rotatably supported on the outer tube member and connected to the oscillating gear so as to allow relative oscillating rotation of the oscillating gear and regulate the relative rotation of the oscillating gear, and a bearing arranged between the outer tube member and the carrier block, wherein the internally toothed pins are formed with an axial length that protrudes axially outward more than the oscillating gear, and the inner race of the bearing is provided with an annular displacement regulating portion that axially laps the end of the internally toothed pin at a position radially inward of the outer tube member more than the internally toothed pin.

[0013] Another aspect of the present invention provides a reducer comprising an outer tube member having a plurality of pin grooves on its inner circumferential surface, internally toothed pins rotatably arranged in each of the pin grooves of the outer tube member, an oscillating gear having external teeth with a number of teeth fewer than the number of the internally toothed pins and which rotates in an oscillating manner while meshing with the internally toothed pins with its external teeth, a carrier block rotatably supported on the outer tube member and connected to the oscillating gear so as to allow relative oscillating rotation of the oscillating gear and regulate the relative rotation of the oscillating gear, and a bearing arranged between the outer tube member and the carrier block, wherein the internally toothed pins are formed with an axial length that protrudes axially outward more than the oscillating gear, and the outer race of the bearing is provided with an annular displacement regulating portion that axially laps the end of the internally toothed pin at a position radially inward of the outer tube member more than the internally toothed pin. [Effects of the Invention]

[0014] The above-mentioned reducers have an annular portion that restricts displacement of the internal pin radially inward of the outer cylindrical member, and therefore can suppress unstable behavior of the internal pin during operation. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a partial cross-sectional front view of the reducer according to the first embodiment. [Figure 2] 2 is a cross-sectional view of the reducer according to the first embodiment taken along line II-II in FIG. 1. [Figure 3] FIG. 3 is an enlarged view of a portion III in FIG. 2 of the reducer according to the first embodiment. [Figure 4] FIG. 3 is an enlarged view of a portion IV in FIG. 2 of the reducer according to the first embodiment. [Figure 5] FIG. 6 is a cross-sectional view similar to FIG. 2 of a reducer according to a second embodiment. [Figure 6] FIG. 6 is an enlarged view of a portion VI in FIG. 5 of a reducer according to a second embodiment. [Figure 7] FIG. 10 is a cross-sectional view of a portion of a reducer according to a third embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a portion of a reducer according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Next, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, common parts are designated by the same reference numerals, and some overlapping descriptions will be omitted.

[0017] [First embodiment] Fig. 1 is a partial cross-sectional front view of a reducer 10 of this embodiment as seen from the input side, and Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. The cross-sectional portion in Fig. 1 corresponds to the cross-section taken along line II in Fig. 2. The reducer 10 comprises an approximately cylindrical case 11 which is an outer tube member, a first carrier block 13A and a second carrier block 13B which are rotatably held on the inner surface of the case 11, multiple (e.g., three) crankshafts 14 which are rotatably supported on the first carrier block 13A and the second carrier block 13B, and a first oscillating gear 15A and a second oscillating gear 15B which oscillate and rotate (orbitally rotate) together with the two eccentric regions 14b of each crankshaft 14. In this embodiment, the first carrier block 13A and the second carrier block 13B constitute a carrier block that is an output rotating body. The case 11 is fixed to a fixed portion such as a knuckle of an industrial robot, and the first carrier block 13A and the second carrier block 13B output the rotation reduced by the reducer 10 to an external rotated body.

[0018] The first carrier block 13A has a perforated disk-shaped base plate 13Aa and a plurality of support columns 13Ab extending from an end face of the base plate 13Aa toward the second carrier block 13B. The second carrier block 13B is also formed in a perforated disk shape. The end faces of the support columns 13Ab of the first carrier block 13A abut against the end faces of the second carrier block 13B, and each support column 13Ab is fastened and fixed to the second carrier block 13B with bolts 16. Note that reference numeral 17 in the drawing denotes a positioning pin for positioning the second carrier block 13B to each support column 13Ab before fastening with the bolts 16.

[0019] An axial gap is secured between the base plate portion 13Aa of the first carrier block 13A and the second carrier block 13B, in which a first oscillating gear 15A and a second oscillating gear 15B are disposed. The first oscillating gear 15A and the second oscillating gear 15B are formed with relief holes 19 through which the support pillars 13Ab of the first carrier block 13A pass. The relief holes 19 are formed to be sufficiently larger than the outer surface shape of the support pillars 13Ab so that the support pillars 13Ab do not interfere with the oscillating rotation of the first oscillating gear 15A and the second oscillating gear 15B.

[0020] The case 11 includes a cylindrical case body 11a and a flange 11b that protrudes radially outward from the outer peripheral surface of the case body 11a. A plurality of bolt insertion holes 29 are formed in the flange 11b and extend axially therethrough. A bolt (not shown) is inserted into each bolt insertion hole 29 to fasten the case 11 to a target portion.

[0021] The case body 11a is disposed across the outer peripheral surface of the base plate portion 13Aa of the first carrier block 13A and the outer peripheral surface of the second carrier block 13B. The base plate portion 13Aa of the first carrier block 13A and the second carrier block 13B are rotatably supported via bearings 12 on both axial end edges of the case body 11a. Furthermore, a plurality of pin grooves 18 extending parallel to the rotational center axis c1 of the first and second carrier blocks 13A and 13B are formed on the inner peripheral surface of the axial central region of the case body 11a (region facing the outer peripheral surfaces of the first oscillating gear 15A and the second oscillating gear 15B). Each pin groove 18 has a semicircular cross section. The plurality of pin grooves 18 are formed at equal pitches in the circumferential direction on the inner peripheral surface of the case body 11a. A substantially cylindrical internally toothed pin 20 is rotatably accommodated in each pin groove 18. A plurality of internally toothed pins 20 attached to the inner peripheral surface of the case body 11a face the outer peripheral surfaces of the first oscillating gear 15A and the second oscillating gear 15B.

[0022] The first oscillating gear 15A and the second oscillating gear 15B are formed with an outer diameter slightly smaller than the inner diameter of the case body 11a. External teeth 15Aa and 15Ba are formed on the outer peripheral surfaces of the first oscillating gear 15A and the second oscillating gear 15B, respectively, which come into meshing contact with a plurality of internally toothed pins 20 arranged on the inner peripheral surface of the case body 11a. The number of teeth of the external teeth 15Aa and 15Ba formed on the outer peripheral surfaces of the first oscillating gear 15A and the second oscillating gear 15B is set to be slightly less (for example, two less) than the number of internally toothed pins 20 (pin grooves 18).

[0023] The multiple crankshafts 14 are arranged on concentric circles centered on the rotational central axis c1 of the first carrier block 13A and the second carrier block 13B. Each crankshaft 14 is rotatably supported by the first carrier block 13A and the second carrier block 13B via bearings 21. Each crankshaft 14 has a pair of shaft support regions 14a spaced apart in the axial direction, and two eccentric regions 14b disposed between the pair of shaft support regions 14a. A gear mounting portion 14c is formed at one axial end of the crankshaft 14 adjacent to the shaft support region 14a. Each shaft support region 14a is inserted through a shaft support hole 13Aa-1 formed in the first carrier block 13A (base portion 13Aa) and a shaft support hole 13Ba-1 formed in the second carrier block 13B, and is rotatably supported by these through bearings 21.

[0024] The central axes c3, c4 of the two eccentric regions 14b of the crankshaft 14 are eccentric with respect to the central axis c2 of the shaft support region 14a. The two eccentric regions 14b are eccentric with respect to the central axis c2 of the shaft support region 14a (the central axis of the crankshaft 14) such that they are out of phase with each other by 180° around the central axis c2 of the shaft support region 14a.

[0025] Each eccentric region 14b of the crankshaft 14 passes through the first oscillating gear 15A and the second oscillating gear 15B. Each eccentric region 14b is rotatably supported via an eccentric portion bearing 23 in a support hole 22 formed in each of the first oscillating gear 15A and the second oscillating gear 15B.

[0026] In the reducer 10 of this embodiment, when the multiple crankshafts 14 are rotated in one direction by an external force, the eccentric regions 14b of the crankshafts 14 oscillate and rotate in the same direction at a predetermined radius, and accordingly the first oscillating gear 15A and the second oscillating gear 15B oscillate and rotate in the same direction at the same radius. At this time, the external teeth 15Aa, 15Ba of the first oscillating gear 15A and the second oscillating gear 15B come into contact with and mesh with the multiple internal tooth pins 20 held on the inner circumference of the case body 11a. The gear mounting portion 14c of each crankshaft 14 penetrates the shaft support hole 13Ba-1 of the second carrier block 13B and protrudes axially outward from the second carrier block 13B. A crankshaft gear 28 is attached to the gear mounting portion 14c protruding from the second carrier block 13B. Each crankshaft gear 28 meshes with an input gear (not shown). The input gear rotates by receiving driving force from a drive motor (not shown).

[0027] In the reducer 10 of this embodiment, the number of teeth of each of the external teeth 15Aa, 15Ba of the first oscillating gear 15A and the second oscillating gear 15B is set slightly less than the number of internally toothed pins 20 (pin grooves 18) on the case main body 11a. Therefore, during one oscillating rotation of the first oscillating gear 15A and the second oscillating gear 15B, the first oscillating gear 15A and the second oscillating gear 15B receive a rotational reaction force from the internally toothed pins 20 on the case main body 11a, and rotate a predetermined pitch in the direction opposite to the oscillating rotation direction. As a result, the first and second carrier blocks 13A, 13B, which are connected to the first oscillating gear 15A and the second oscillating gear 15B via the crankshaft 14, rotate in the same direction and at the same pitch together with the first and second oscillating gears 15A, 15B. As a result, the rotation of the crankshaft 14 is decelerated and output as the rotation of the first and second carrier blocks 13A, 13B. In this embodiment, the two eccentric regions 14b of the crankshaft 14 are eccentric so as to be shifted by 180° around the axis, so the oscillating rotation phases of the first oscillating gear 15A and the second oscillating gear 15B are shifted by 180°.

[0028] In the above, an example has been described in which the outer cylindrical member (case 11) is fixed to the fixed part and the carrier blocks (first carrier block 13A and second carrier block 13B) are connected to the rotated body. However, conversely, it is also possible to connect the outer cylindrical member to the rotated body and fix the carrier blocks to the fixed part. In this case, while the first oscillating gear 15A and the second oscillating gear 15B make one revolution, their rotation is restricted by the carrier blocks (first carrier block 13A and second carrier block 13B), and during that time, the outer cylindrical member (case 11) is pushed and moved by a predetermined pitch in the same direction as the oscillating rotation direction of the first oscillating gear 15A and the second oscillating gear 15B. Therefore, in this configuration, the rotation reduced by the reducer 10 can be output to the outside (rotated part) through the outer cylindrical member.

[0029] 3 is an enlarged view of part III in FIG. 2, and FIG. 4 is an enlarged view of part IV in FIG. The first and second oscillatory gears 15A and 15B are formed in the shape of perforated disks, with bosses 30 formed on the opposing inner peripheral side surfaces. Each boss 30 is formed in a radially inner region of the opposing side surfaces of the first and second oscillatory gears 15A and 15B relative to the portion where the support hole 22 (the insertion portion of the crankshaft 14) is formed. Each boss 30 is formed in a circular shape concentric with the outer peripheral shape of the first and second oscillatory gears 15A and 15B. The first and second oscillatory gears 15A and 15B abut against each other via their bosses 30. Because the first and second oscillatory gears 15A and 15B have the abutting bosses 30 formed on their inner peripheral edges, a gap is secured between the outer peripheral edges 15e of the first and second oscillatory gears 15A and 15B, as shown in FIG. 3. That is, a separation width D equal to the sum of the protruding dimensions A and B of the boss portions 30 is secured between the outer peripheral edge portions 15e of the first oscillating gear 15A and the second oscillating gear 15B. The first and second oscillating gears 15A, 15B are subjected to hardening treatment such as carburizing and quenching on the entire surface including the boss portion 30. Therefore, even when the first oscillating gear 15A and the second oscillating gear 15B undergo relative rotational displacement, there is almost no wear between the boss portions 30.

[0030] As shown in FIGS. 2 and 4, an annular displacement-restricting member 31 is disposed in the gap between the outer peripheral edges 15e of the first and second oscillatory gears 15A and 15B. The displacement-restricting member 31 is formed, for example, in the shape of a short cylinder made of a metal material. The displacement-restricting member 31 has an inner diameter that faces only the radially outer portion of the outer peripheral edges 15e of the first and second oscillatory gears 15A and 15B, which is located further radially outward than the position where the support hole 22 is formed. The axial width C (the width of the outer cylindrical member in the axial direction) is narrower than the separation width (D = A + B) between the outer peripheral edges 15e of the adjacent first and second oscillatory gears 15A and 15B. Therefore, the displacement-restricting member 31 disposed between the outer peripheral edges 15e of the first and second oscillatory gears 15A and 15B can maintain a small axial gap d1 (0.1 to 0.2 mm) between the outer peripheral edges 15e of the first and second oscillatory gears 15A and 15B.

[0031] The displacement restriction member 31, which is disposed between the outer peripheral edge portions 15e of the first and second oscillating gears 15A and 15B, is disposed radially inward of the case 11 relative to the internally toothed pins 20 housed in the pin grooves 18 of the case 11. The outer peripheral surface of the displacement restriction member 31 faces the axial central region of each internally toothed pin 20, and restricts excessive displacement of the internally toothed pins 20 radially inward of the case 11.

[0032] As described above, in the reducer 10 of this embodiment, the annular displacement restriction member 31 that restricts displacement of the internal pin 20 radially inward of the case 11 (outer cylindrical member) is disposed between the outer peripheral edge portions 15e of the adjacent first and second oscillating gears 15A and 15B. Therefore, when the meshing depth between the internal pin 20 and some of the external teeth 15Aa and 15Ba of the first and second oscillating gears 15A and 15B becomes shallow during operation of the reducer 10, the internal pin 20 abuts against the outer peripheral surface of the displacement restriction member 31, thereby preventing the internal pin 20 from separating from the pin groove 18. Therefore, when the reducer 10 of this embodiment is employed, unstable behavior of the internal pin 20 during operation is suppressed, and the operation of the reducer 10 can be made more stable.

[0033] Furthermore, in the reducer 10 of this embodiment, the width C of the displacement restricting member 31 in the axial direction of the case 11 (outer cylindrical member) is set to be narrower than the width (separation width D) between the outer peripheral edge portions 15e of the first and second oscillating gears 15A and 15B. This makes it possible to prevent the outer peripheral edge portions 15e of the first and second oscillating gears 15A and 15B from coming into strong contact with the side surface of the displacement restricting member 31 during oscillating rotation of the first and second oscillating gears 15A and 15B. Therefore, when this configuration is adopted, wear and damage to the displacement restricting member 31 can be suppressed, and the expected performance of the displacement restricting member 31 can be maintained for a long period of time.

[0034] Furthermore, in the reducer 10 of this embodiment, a gap d1 can be secured between the annular displacement restriction member 31 and the outer peripheral edge portions 15e of the first and second oscillating gears 15A and 15B, so that the lubricating liquid filled in the case 11 can efficiently flow through the gap d1 in the direction of the internal pin 20. Therefore, when this configuration is adopted, the lubrication of the internal pin 20 can be improved.

[0035] Furthermore, in the reducer 10 of this embodiment, boss portions 30 are provided on the inner peripheral edges of the first and second oscillating gears 15A and 15B so as to abut against each other in the axial direction of the case 11 (outer cylindrical member). Therefore, by controlling the protruding height of the boss portions 30, the width D between the outer peripheral edges 15e of the first and second oscillating gears 15A and 15B can be easily and accurately set and adjusted.

[0036] [Second embodiment] 5 is a cross-sectional view of the reducer 110 of this embodiment, similar to FIG. 2 of the first embodiment. Also, FIG. 6 is an enlarged view of a portion VI in FIG. Similar to the first embodiment, the reducer 110 of this embodiment includes a case 11, which is an outer cylindrical member, a first carrier block 13A, a second carrier block 13B, a crankshaft 14, a first oscillating gear 15A, and a second oscillating gear 15B. These basic components are similar to those of the first embodiment. However, in the reducer 110 of this embodiment, no displacement restriction member is disposed between the outer peripheral edges of the first oscillating gear 15A and the second oscillating gear 15B.

[0037] In the reducer 110 of this embodiment, a shoulder 35A (adjacent portion) adjacent to the axially outer side of the first oscillating gear 15A is provided on the outer peripheral edge of the base plate portion 13Aa of the first carrier block 13A, and a cylindrical (annular) displacement regulating portion 36A protruding toward the first oscillating gear 15A is integrally formed with the shoulder 35A. Furthermore, a shoulder 35B (adjacent portion) adjacent to the axially outer side of the second oscillating gear 15B is provided on the outer peripheral edge of the second carrier block 13B, and a cylindrical (annular) displacement regulating portion 36B protruding toward the second oscillating gear 15B is integrally formed with the shoulder 35B. The displacement regulating portions 36A, 36B axially overlap each end of the internally toothed pin 20 at a position radially inward of the case 11 from the internally toothed pin 20.

[0038] In this embodiment, the outer peripheral surface of the shoulder 35A of the first carrier block 13A forms an inner race of one bearing 112, and the outer peripheral surface of the shoulder 35B of the second carrier block 13B forms an inner race of the other bearing 112. One bearing 112 is disposed between the first carrier block 13A and one axial end of the case 11, and the other bearing 112 is disposed between the second carrier block 13B and the other axial end of the case 11. An outer race 112o of one bearing 112 abuts against an inner peripheral surface of the one axial end of the case 11 and one end face 18e of the portion where the pin groove 18 is formed, which is axially outward. Similarly, an outer race 112o of the other bearing 112 abuts against an inner peripheral surface of the other axial end of the case 11 and the other end face 18e of the portion where the pin groove 18 is formed, which is axially outward.

[0039] The cylindrical displacement restriction portions 36A, 36B of the first and second carrier blocks 13A, 13B are disposed radially inward of the case 11 relative to the internally toothed pins 20 housed in the pin grooves 18 of the case 11. As shown in Fig. 6, the displacement restriction portion 36B protrudes axially inward (toward the second oscillating gear 15B) by a predetermined length E from the other end face 18e of the portion where the pin groove 18 is formed. Although not shown here, the displacement restriction portion 36A on the opposite side protrudes axially inward (toward the first oscillating gear 15A) by a predetermined length E from one end face 18e of the portion where the pin groove 18 is formed.

[0040] Furthermore, the internally toothed pins 20 housed in the pin grooves 18 of the case 11 are formed with an axial length that protrudes axially outward beyond the first and second oscillating gears 15A and 15B. In other words, the axial length of the internally toothed pins 20 is longer than the combined axial width of the first oscillating gear 15A and the second oscillating gear 15B. However, the axial length of the internally toothed pins 20 is set shorter than the axial width of the portion of the case 11 where the pin grooves 18 are formed. Therefore, the axial ends of the internally toothed pins 20 housed in the pin grooves 18 do not interfere with the ends of the outer race 112o of the bearing 112, preventing them from becoming unable to rotate.

[0041] 6, the annular displacement regulating portions 36A, 36B of the first and second carrier blocks 13A, 13B overlap a predetermined amount in the axial direction with the axial end of the internally toothed pin 20 housed in the pin groove 18. Therefore, when the internally toothed pin 20 attempts to come out of the pin groove 18 during oscillating rotation of the first and second oscillating gears 15A, 15B, the axial end of the internally toothed pin 20 comes into contact with the outer peripheral surface of the annular displacement regulating portions 36A, 36B, thereby regulating the displacement of the internally toothed pin 20 from coming out of the pin groove 18. Note that the protruding length E in the lapping direction of the displacement restricting portions 36A and 36B with respect to the end face 18e of the formation portion of the pin groove 18 is set to be shorter (E < F) than the length F from the end faces on the outer sides in the axial direction of the first and second oscillating gears 15A and 15B to the end face of the outer race 112o of the bearing 112 (up to the end face 18e of the formation portion of the pin groove 18). For this reason, the displacement restricting portions 36A and 36B do not interfere with the end faces in the axial direction of the first and second oscillating gears 15A and 15B, and the oscillating rotation of the first and second oscillating gears 15A and 15B is not hindered.

[0042] As described above, in the speed reducer 110 of the present embodiment, the internal tooth pin 20 is formed to have an axial length that protrudes outward in the axial direction from the first and second oscillating gears 15A and 15B, and cylindrical displacement restricting portions 36A and 36B that lap with the end portions of the internal tooth pin 20 in the axial direction at positions radially inside the case 11 with respect to the internal tooth pin 20 are provided at the respective shoulder portions 35A and 35B (adjacent arrangement portions) of the first and second carrier blocks 13A and 13B. For this reason, when the meshing depth of a part of the external teeth 15Aa and 15Ba of the first and second oscillating gears 15A and 15B and the internal tooth pin 20 becomes shallow during the operation of the speed reducer 110, the internal tooth pin 20 abuts against the outer peripheral surface of the displacement restricting portions 36A and 36B, and thus the separation of the internal tooth pin 20 from the pin groove 18 can be suppressed. Therefore, when the speed reducer 110 of the present embodiment is adopted, the unstable behavior of the internal tooth pin 20 during operation can be suppressed, and the operation of the speed reducer 110 can be made more stable.

[0043] Also, in the speed reducer 110 of the present embodiment, cylindrical displacement restricting portions 36A and 36B that protrude inward in the axial direction are integrally formed at the respective shoulder portions 35A and 35B (adjacent arrangement portions) of the first and second carrier blocks 13A and 13B, and the displacement restricting portions 36A and 36B suppress the separation of the internal tooth pin 20 from the pin groove 18. For this reason, unlike the case of adding a dedicated part for suppressing the separation of the internal tooth pin 20 from the pin groove 18, the number of parts can be reduced, and the axial length of the speed reducer 110 can be shortened.

[0044] [Third Embodiment] FIG. 7 is a view showing a part of a cross section similar to FIG. 2 of the first embodiment of the speed reducer 210 of the present embodiment. The reducer 210 of this embodiment differs from that of the second embodiment only in the configuration of the displacement regulating sections 236A, 236B that regulate the displacement of the internal tooth pin 20 from the pin groove 18, and the other configurations are the same as those of the second embodiment.

[0045] In the reducer 210 of this embodiment, the bearing 212 interposed between the case 11 and the first and second carrier blocks 13A, 13B includes an outer race 212o and an inner race 212i, and the inner race 212i is fixed to the outer peripheral edge portions of the first and second carrier blocks 13A, 13B. The outer race 212o abuts against the inner peripheral surface of the axial end of the case 11 and the axially outer end surface of the portion where the pin groove 18 is formed. The inner race 212i of each bearing 212 is integrally formed with cylindrical (annular) displacement restriction portions 236A, 236B that extend linearly axially inward of the outer race 212o (on the side facing the first and second oscillating gears 15A, 15B).

[0046] The internal pins 20 housed in the pin grooves 18 of the case 11 are formed with an axial length that protrudes axially outward beyond the first and second oscillating gears 15A, 15B. In the present embodiment as well, the axial length of the internal pins 20 is set shorter than the axial width of the portion of the case 11 where the pin grooves 18 are formed. The cylindrical displacement regulating portions 236A, 236B of each bearing 212 axially overlap the end of the internal pin 20 at a position radially inward of the case 11 relative to the internal pin 20.

[0047] Furthermore, in this embodiment, the protruding length in the wrap direction of the displacement regulating portions 236A, 236B from the end face of the pin groove forming portion of the case 11 is set to be shorter than the length from the axially outer end faces of the first and second oscillating gears 15A, 15B to the end face of the outer race 212o of the bearing 212 (to the end face of the forming portion of the pin groove 18). Therefore, in this embodiment as well, the displacement regulating portions 236A, 236B do not interfere with the axial end faces of the first and second oscillating gears 15A, 15B, and the oscillating rotation of the first and second oscillating gears 15A, 15B is not hindered.

[0048] As described above, in the reducer 210 of this embodiment, the internal tooth pin 20 is formed with an axial length that protrudes axially outward beyond the first and second oscillating gears 15A and 15B, and cylindrical displacement restriction portions 236A and 236B that axially overlap the end of the internal tooth pin 20 are formed integrally with the inner race 212i of the bearing 212 at a position radially inward of the case 11 relative to the internal tooth pin 20. Therefore, even in a situation where the meshing depth of the internal tooth pin 20 with some of the external teeth 15Aa and 15Ba of the first and second oscillating gears 15A and 15B becomes shallow during operation of the reducer 110, the internal tooth pin 20 abuts against the outer peripheral surfaces of the displacement restriction portions 236A and 236B, thereby preventing the internal tooth pin 20 from separating from the pin groove 18. Therefore, when the reducer 210 of this embodiment is employed, unstable behavior of the internal tooth pin 20 during operation is prevented, and the operation of the reducer 210 can be made more stable.

[0049] Furthermore, in the reducer 210 of this embodiment, cylindrical displacement restriction portions 236A, 236B that protrude axially inward are formed integrally with the inner race 212i of the bearing 212. Therefore, unlike when a dedicated part is added to suppress separation of the internal tooth pin 20 from the pin groove 18, it is possible to reduce the number of parts and shorten the axial length of the reducer 110.

[0050] [Fourth embodiment] FIG. 8 is a view showing a part of a cross section of a reducer 310 of this embodiment, similar to FIG. 2 of the first embodiment. The reducer 310 of this embodiment differs from that of the second embodiment only in the configuration of the displacement regulating section 336B that regulates the displacement of the internal tooth pin 20 from the pin groove 18, and the other configurations are the same as those of the second embodiment.

[0051] In the reducer 310 of this embodiment, a displacement restriction portion 336B is formed integrally with an outer race 312o of a bearing 312 interposed between the case 11 and the first and second carrier blocks (only the second carrier block 13B is shown in FIG. 8). In this embodiment, the inner race of the bearing 212 is formed by a part of the carrier block (13B). The outer race 312o abuts against the inner peripheral surface of the axial end of the case 11 and the axially outer end face of the portion where the pin groove 18 is formed.

[0052] The internally toothed pins 20 housed in the pin grooves 18 of the case 11 are formed with an axial length that protrudes axially outward beyond the first and second oscillating gears 15A, 15B. The axial length of the internally toothed pins 20 is set shorter than the axial width of the portion of the case 11 where the pin grooves 18 are formed.

[0053] The outer race 312o of the bearing 312 has an outer race body 40 that abuts against the inner circumferential surface of the axial end of the case 11 and the axially outer end face of the portion where the pin groove 18 is formed, an inward flange 41 that extends radially inward from the axially inner end of the outer race body 40, and a short-axis cylindrical displacement restricting portion 336B that protrudes and extends axially inward from the radially inner end of the inward flange 41. The displacement restricting portion 336B of the outer race 312o axially overlaps the end of the internal pin 20 at a position radially inward of the case 11 relative to the internal pin 20.

[0054] Furthermore, the length of protrusion of the displacement regulating portion 336B in the wrap direction relative to the end face of the pin groove forming portion of the case 11 is set to be shorter than the length from the axially outer end faces of the first and second oscillating gears 15A and 15B to the end face of the outer race body 40 (to the end face of the forming portion of the pin groove 18). Therefore, in the case of this embodiment as well, the displacement regulating portion 336B does not interfere with the axial end faces of the first and second oscillating gears 15A and 15B to hinder the oscillating rotation of the first and second oscillating gears 15A and 15B.

[0055] As described above, in the reducer 310 of this embodiment, the internal tooth pin 20 is formed with an axial length that protrudes axially outward beyond the first and second oscillating gears 15A and 15B, and a cylindrical displacement restricting portion 336B that axially overlaps the end of the internal tooth pin 20 is formed integrally with the outer race 312o of the bearing 312 at a position radially inward of the case 11 relative to the internal tooth pin 20. Therefore, even in a situation where the meshing depth of the internal tooth pin 20 with some of the external teeth 15Aa and 15Ba of the first and second oscillating gears 15A and 15B becomes shallow during operation of the reducer 110, the internal tooth pin 20 abuts against the outer peripheral surface of the displacement restricting portion 336B, thereby preventing the internal tooth pin 20 from separating from the pin groove 18. Therefore, when the reducer 310 of this embodiment is employed, unstable behavior of the internal tooth pin 20 during operation is prevented, and the operation of the reducer 310 can be made more stable.

[0056] Furthermore, in the reducer 310 of this embodiment, the displacement restriction portion 336B is formed integrally with the outer race 312i of the bearing 312. Therefore, unlike when a dedicated part is added to suppress the separation of the internal tooth pin 20 from the pin groove 18, the number of parts can be reduced and the axial length of the reducer 110 can also be shortened.

[0057] The present invention is not limited to the above-described embodiment, and various design modifications are possible without departing from the spirit of the present invention. For example, in each of the above embodiments, two oscillating gears are arranged inside the outer cylindrical member (case), but the number of oscillating gears arranged inside the outer cylindrical member is not limited to two. In the first embodiment, the number of oscillating gears may be two or more. Furthermore, in the second to fourth embodiments, the number of oscillating gears may be one, or three or more. [Explanation of symbols]

[0058] 10, 110, 210, 310... reducer, 11... case (external cylindrical member), 13A... first carrier block (carrier block), 13B... second carrier block (carrier block), 15A... first oscillating gear (oscillating gear), 15B... second oscillating gear (oscillating gear), 15Aa, 15Ba... external teeth, 15e... outer peripheral edge portion 15e, 18... pin groove, 20... internal tooth pin, 31... displacement control member, 35A, 35B... shoulder portion (adjacent arrangement portion), 36A, 36B, 236A, 236B, 326B... displacement control portion, 212, 312... bearing, 212i... inner race, 312o... outer race.

Claims

[Claim 1] an outer cylindrical member having a plurality of pin grooves on its inner circumferential surface; an internally toothed pin rotatably disposed in each of the pin grooves of the outer cylindrical member; a plurality of oscillating gears each having a number of external teeth less than the number of the internal pins, the external teeth of which mesh with the internal pins and which oscillate and rotate; a carrier block that is rotatably supported by the outer cylindrical member, allows relative oscillating rotation of the oscillating gear, and is linked to the oscillating gear so as to restrict relative rotation of the oscillating gear, an annular displacement restriction member is disposed between the outer peripheral edges of the adjacent oscillating gears to restrict displacement of the internal tooth pin radially inward of the outer cylindrical member; The reducer has boss portions provided on inner peripheral edges of adjacent oscillating gears, the boss portions abutting against each other in the axial direction of the outer cylindrical member.

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