Axial conversion gear device

Abstract

Axial conversion gear device (X1), comprising: at least one crankshaft (10) with a main shaft body (10c), an eccentric part (10a, 10b) that is eccentric to the main shaft body (10c), and a shaft wheel (10b) that is arranged on the main shaft body (10c); an eccentrically rotating gear (14, 16) with a plurality of external teeth (14a, 16a) which is set into eccentric rotation due to the rotation of the eccentric part (10a, 10b); a transmitting gear shaft (6) with a first gear (6a) which meshes with the shaft gear (10d) of the crankshaft (10) and a second gear (6b) which is spaced apart from the first gear (6a) in an axial direction of the first gear (6a); an axial conversion unit (8) comprising an externally toothed gear (8a) meshing with the second gear (6b), and an axial conversion gear (8b) which converts an input torque applied to an input shaft (20) into a torque in an axial direction of the externally toothed gear (8a); and an outer cylinder (2) with a plurality of internal teeth (3) which each mesh with the external teeth (14a, 16a) of the eccentrically rotating gear (14, 16), wherein the axial conversion gear (8b) is arranged in the axial direction of the externally toothed gear (8a) between the first gear (6a) and the second gear (6b).

Description

Technical area

[0001] The present invention relates to an axial conversion gear device. State of the art

[0002] An axial conversion gear device that converts a first direction of input torque into a second direction is known.

[0003] Fig. 4 shows a gear transmission device described in JP 2010-101366 A and US 2009 / 0 118 050 A1, respectively, as an example of an axial conversion gear device. The gear transmission device includes an axial conversion unit 200 and a reduction unit 300. The axial conversion unit 200 includes a first bevel gear 210, a second bevel gear 220 meshing with the first bevel gear 200, and a drive gear 230 that shares the same axis as the second bevel gear 220 and whose outer diameter is smaller than the second bevel gear 220.The reduction unit 300, on the other hand, has a sun gear with a first external gear 310 and a second external gear 320 whose diameter is larger than that of the first external gear 310, a crankshaft with an external gear 330 that meshes with the first external gear 310 and an eccentric part 340, and an externally toothed gear 350 that oscillates and rotates when the eccentric part 340 oscillates and rotates. The second external gear 320 of the sun gear meshes with the drive gear 230 of the axial conversion unit 200, and the second bevel gear 220 is farther from the first external gear 310 in an axial direction of the drive gear 230 than the drive gear 230. In the gear transmission device, the input torque of an engine is transmitted through the first bevel gear 210 to the second bevel gear 220, so that the input torque is transmitted in the axial direction of the drive gear 230.The torque is transmitted from the drive gear 230 through the sun gear and the crankshaft to the externally toothed gear 350. This causes the externally toothed gear 350 to oscillate and rotate.

[0004] Fig. 5 shows a gear transmission device described in JP 2010-159851 A. In this gear transmission device, a drive gear 230 is located closer to a near-ground side B1 than the second bevel gear 220 in an axial direction of the drive gear 230. The drive gear 230 and an outer gear 330 of a crankshaft are located almost on the same plane.

[0005] In the gear transmission device described in JP 2010-101366 A and US 2009 / 118050 A1, since the second bevel gear 220 and the drive gear 230 have the same axis, the gear transmission device can be prevented from becoming radially excessive. However, in this gear transmission device, the second bevel gear 220 is located farther from the first external gear 310 in the axial direction of the drive gear 230 than the drive gear 230. Thus, the first bevel gear 210 meshes with the second bevel gear 220, and the motor that outputs torque to the first bevel gear 210 is located far from the first external gear 310 in the axial direction of the drive gear 230. The bottom surface B1 of the gear transmission device is designed based on, for example, a height of a side surface of the motor.Thus, when the motor is located far from the first outer gear 310 in the axial direction of the drive gear 230, the bottom surface B1 is far from the first outer gear 310. This creates a dead space between the second bevel gear 220 and the bottom surface B1 of the gear transmission device in the axial direction of the drive gear 230. This is likely to cause the gear transmission device to be oversized in the axial direction. In contrast, in JP 2010-159851 A, since the drive gear 230 is located axially closer to the bottom surface B1 than the second bevel gear 220, the gear transmission device can be prevented from becoming oversized axially.However, in this gear transmission device, since the drive gear 230 and the outer gear 330 are located almost on the same plane, the axes of the second bevel gear 220 and the drive gear 230 must be arranged at a certain distance from the axis of the crankshaft with the outer gear 330 to prevent the drive gear 230 and the outer gear 330 from interfering with each other. This makes it difficult to keep the gear transmission device small in the radial direction. Summary of the invention

[0006] The present invention was conceived in view of the above-mentioned points. An object of the present invention is to provide an axial conversion gear device that can be prevented from becoming too large axially and kept small in the radial direction.

[0007] An axial conversion gear device according to the present invention comprises: at least one crankshaft having a shaft main body, an eccentric part eccentric to the shaft main body, and a shaft gear arranged on the shaft main body; an eccentrically rotating gear having a plurality of external teeth, which is driven into eccentric rotation due to the rotation of the eccentric part; a transmitting gear shaft having a first gear meshing with the shaft gear of the crankshaft and a second gear spaced from the first gear in an axial direction of the first gear; an axial conversion unit having an externally toothed gear meshing with the second gear and an axial conversion gear that converts an input torque applied to an input shaft into a torque in an axial direction of the externally toothed gear;and an outer cylinder having a plurality of internal teeth each meshing with the external teeth of the eccentrically rotating gear, wherein the axial conversion gear is arranged between the first gear and the second gear in the axial direction of the externally toothed gear; Short description of the drawings Fig. 1 is a cross-sectional view of a structural outline of an axial conversion gear device according to an embodiment of the present invention; Fig. 2 is a cross-sectional view along the line II-II of Fig. 1; Fig. 3 is a schematic diagram showing a relationship of the outer peripheries of individual elements of the axial conversion gear device according to the present invention; Fig. 4 is a cross-sectional view of a structural sketch of a gear transmission device described in JP 2010-101366 A and US 2009 / 118050 A1, respectively; and Fig. 5 is a cross-sectional view of a structural sketch of a gear transmission device described in JP 2010-159851 A. Description of implementation examples

[0008] An embodiment of the present invention will be described below with reference to the drawings. The following embodiment is merely a concrete implementation of the present invention and is not intended to limit the technical scope of the present invention in any way.

[0009] Furthermore, an embodiment of the present invention will be described with reference to the accompanying drawings. For better understanding, the figures mentioned in the following description only illustrate simplified main elements of components of an axial conversion gear device X1 according to the present embodiment. Thus, the axial conversion gear device X1 according to the present embodiment may also include components that are not illustrated in the figures mentioned in the present description.

[0010] The axial conversion gear device according to the present embodiment is a reduction gear that converts torque from one axial direction into torque in another axial direction. The following will be explained with reference to Fig. 1 and Fig. 2 a structure of the axial conversion transmission device X1 is described in detail.

[0011] The axial conversion transmission device X1 mainly includes an outer cylinder 2, a carrier 4, a crankshaft 10, a first oscillating gear 14, a second oscillating gear 16, a cylindrical member 5, a transmitting gear 6, an axial conversion unit 8, and an input shaft 20.

[0012] According to the present embodiment, the outer cylinder 2 is a rotation-side member of the axial conversion gear device X1. The outer cylinder 2 includes a first member 2A having an axial end surface forming an upper surface S1 of the axial conversion gear device X1, and a second member 2B disposed on one side in an axial direction of the first member (on a lower side of the first member 2A as shown in Fig. 1). The first element 2A has a through-hole in a central portion surrounding a central axis C1. The cylindrical element 5 is inserted into the through-hole. The second element 2B has a cylindrical shape with a cavity adjacent to the through-hole of the first element 2A. The first element 2A and the second element 2B are fastened to each other by means of a plurality of screws B1 arranged at equal intervals in a circumferential direction of the outer cylinder 2.

[0013] Numerous pin grooves 2b are formed on an inner peripheral surface of the second member 2B of the outer cylinder 2. The pin grooves 2b extend in the axial direction of the outer cylinder 2 and have a semicircular cross-sectional shape perpendicular to the axial direction. These pin grooves 2b are located at equal intervals in a circumferential direction in the outer cylinder 2.

[0014] The outer cylinder 2 has numerous internal pins 3. The internal pins 3 are fixed in the pin grooves 2b of the second member 2B. The internal pins 3 are inserted into the corresponding pin grooves 2b such that the internal pins 3 extend in the axial direction of the outer cylinder 2. Thus, the numerous internal pins 3 are arranged at equal intervals in the circumferential direction of the outer cylinder 2. The internal pins 3 mesh with a first externally toothed element 14a of the first oscillating gear 14 and a second externally toothed element 16a of the second oscillating gear 16.

[0015] The carrier 4 is a fixed side member of the axial conversion transmission device X1 according to the present embodiment. The carrier 4 is arranged around the central axis C1 of the outer cylinder 2. A part of the carrier 4 is enclosed in the outer cylinder 2. Between the outer cylinder 2 and the carrier 4 enclosed in the outer cylinder 2 are a pair of main bearings 18a and 18b spaced apart from each other in the axial direction of the axial conversion transmission device X1. Thanks to the main bearings 18a and 18b, the carrier 4 and the outer cylinder 2 can rotate relative to each other.

[0016] The carrier 4 includes a base 4a, a plurality of shaft elements 4c, and an end plate element 4b. According to the present embodiment, the base 4a and the shaft elements 4c are integrally formed. The shaft elements 4c and the end plate element 4b are formed separately. The end plate element 4b is fixed to the shaft elements 4c using a plurality of screws B2. Alternatively, the base 4a, the shaft elements 4c, and the end plate element 4b may be independent elements and not integrally formed. In this case, the base 4a, the shaft elements 4c, and the end plate element 4b are fixed using, for example, screws B2.

[0017] The base 4a functions as a base of the carrier 4. The base 4a is arranged opposite the end plate member 4b in the axial direction of the axial conversion gear device X1 through the oscillating gears 14 and 16. The base 4a has a main body member 4d and a protrusion member 4e protruding from a side surface of the main body member 4d.

[0018] The main body member 4d has an axial end surface forming a bottom surface S2 of the axial conversion gear device X1. The main body member 4d encloses a part of the cylindrical member 5, a part of the crankshaft 10, the transmitting gear 6, and the axial conversion unit 8. Specifically, the main body member 4d includes a first space A1, a second space A2, a third space A3, and a crankshaft opening. The first space A1 penetrates the central portion of the main body member 4d in the axial direction of the axial conversion gear device X1. The first space A1 communicates with the through hole of the first member 2A of the outer cylinder 2. The first space A1 encloses a part of the cylindrical member 5. The second space A2 circumferentially surrounds the first space A1 at a central portion in the axial direction of the first space A1.The second space A2 encloses the transmission gear 6 arranged around the cylindrical member 5. The third space A3 extends radially from the second space A2 and is open on the side surface of the main body member 4d. The third space A3 accommodates the axial conversion unit 8. The crankshaft opening is formed around the first space A1. The crankshaft opening extends in the axial direction of the axial conversion gear device X1. The crankshaft opening of the main body member 4d encloses a shaft main body 10c and a shaft gear 10d of the crankshaft 10.

[0019] The main body member 4d has the first space A1, the second space A2, the third space A3, and the crankshaft opening formed as mentioned above. The main body member 4d has a first side part 4f located on one side in the axial direction of the second space A2 (on an upper surface S1, as shown in Fig. 1), a second side part 4g located on another side in the axial direction of the second space A2 (on a lower surface S2 as shown in Fig. 1), and a connecting part 4k connecting the first side part 4f and the second side part 4g. The third space A3, which extends radially, is formed in a part of the connecting part 4k.

[0020] The protrusion element 4e is formed on the side surface of the main body element 4d. Specifically, the protrusion element 4b has a fourth space A4. The fourth space A4 is a space through which the protrusion element 4b extends in a direction perpendicular to the axial direction of the axial conversion gear device X1. The fourth space A4 accommodates the input shaft 20. The fourth space A4 is connected to the third space A3 opening on the side surface of the main body element 4d.

[0021] The end plate member 4b and the base 4a support the crankshaft 10 on both sides of the oscillating gears 14 and 16. The end plate member 4b is positioned opposite the base 4a in the axial direction of the axial conversion gear device X1 through the oscillating gears 14 and 16. Formed in the end plate member 4b are a through hole into which the cylindrical member 5 is inserted, and the crankshaft opening enclosing an end portion of the crankshaft 10 opposite the shaft gear 10d.

[0022] The shaft element 4c extends in the axial direction of the base 4a and the end plate element 4b and connects to the base 4a and the end plate element 4b. Specifically, the shaft elements 4c are located between the base 4a and the end plate element 4b and are inserted into insertion holes 14c and 16c of the oscillating gears 14 and 16. One end of the shaft elements 4c is connected to the base 4a, respectively. The other end of the shaft elements 4c is fixed to an end plate element 4b by means of the screw B2. The shaft elements 4c are arranged in the circumferential direction of the carrier 4 such that the shaft elements 4c space the center axis C1 by a predetermined distance. According to the present embodiment, six shaft elements 4c are arranged. Alternatively, the number of shaft elements 4c can be changed according to the use of the axial conversion gear device X1.

[0023] The crankshafts 10 are evenly arranged in the circumferential direction of the carrier 4 so that the crankshafts 10 space the center axis C1 by a predetermined distance. The crankshafts 10 are inserted into the insertion holes 14b and 16b of the oscillating gears 14 and 16, and are also received in the crankshaft holes of the base 4a and the end plate member 4b. A pair of axially spaced crankshaft bearings 12a and 12b are respectively disposed between the crankshafts 10 and the carrier 4. Thanks to the crankshaft bearings 12a and 12b, the crankshafts 10 can rotate relative to the carrier 4. According to the present embodiment, three crankshafts 10 are arranged. Alternatively, the number of crankshafts 10 can be changed according to the use of the axial conversion gear device X1.

[0024] The crankshafts 10 each have a shaft main body 10c, a first eccentric part 10a, a second eccentric part 10b and a shaft gear 10b.

[0025] The shaft main body 10c forms an axis of the crankshaft 10 and extends along the center axis C1 of the axial conversion gear device X1.

[0026] The first eccentric part 10a and the second eccentric part 10b each have a cylindrical shape and are integrally formed with the shaft main body 10c, so that the first eccentric part 10a and the second eccentric part 10b are eccentric from the axis of the shaft main body 10c by a predetermined eccentric amount. The first eccentric part 10a and the second eccentric part 10b are eccentric from the axis of the shaft main body 10c by predetermined eccentric amounts. The first eccentric part 10a and the second eccentric part 10b are arranged to have a phase difference of predetermined angles.

[0027] The shaft gear 10d is fixed at one end portion to the bottom surface S2 in the axial direction of the shaft main body 10c. When the shaft gear 10d rotates, the entire crankshaft 10 rotates.

[0028] The oscillating gears 14 and 16 are arranged in the second member 2B of the outer cylinder 2 and between the base 4a and the end plate member 4b. An outer diameter of the oscillating gears 14 and 16 is each slightly smaller than an inner diameter of the second member 2B of the outer cylinder 2. The oscillating gears 14 and 16 have through holes extending in the axial direction of the axial conversion gear device X1. The cylindrical member 5 is inserted into the through holes.

[0029] The first oscillating gear 14 has a first externally toothed element 14a, a plurality of insertion holes 14b, and a plurality of insertion holes 14c. The first externally toothed element 14a is a member whose consecutive teeth are evenly formed on the entire circumference of the first oscillating gear 14. A number of teeth of the first externally toothed element 14a is smaller than a number of the internal tooth pins 3. The insertion holes 14b are members into which the eccentric parts 10a are inserted. In the insertion holes 14b, the first oscillating gear 14 is fixed to the first eccentric parts 10a through a plurality of first roller bearings. The insertion holes 14c are members into which the shaft elements 4c are inserted. An outer diameter of the insertion holes 14c is each slightly larger than an outer diameter of the individual shaft elements 4c.

[0030] When the first eccentric part 10a rotates eccentrically while the crankshaft 10 rotates, the first oscillating gear 14 oscillates and rotates while the first externally toothed element 14a is engaged with the internal toothed pins 3.

[0031] The second oscillating gear 16 is located closer to the base 4a side than the first oscillating gear 14. The second oscillating gear 16 has the same structure as the first oscillating gear 14. Specifically, the second oscillating gear 16 has a second externally toothed member 16a, a plurality of insertion holes 16b, and a plurality of insertion holes 16c. In the insertion holes 16b, the second oscillating gear 16 is fixed to the second eccentric members 10b through a plurality of second roller bearings.

[0032] When the second eccentric part 10b rotates eccentrically while the crankshaft 10 rotates, the second oscillating gear 16 oscillates and rotates while the second externally toothed member 16a is engaged with the internal toothed pins 3.

[0033] According to the present embodiment, the first oscillating gear 14 and the second oscillating gear 16 are used, which differ in phase. Alternatively, only one oscillating gear or three oscillating gears can be used.

[0034] The cylindrical member 5 is arranged so that it extends in the axial direction of the axial conversion transmission device X1 through the outer cylinder 2, the carrier 4, and the oscillating gears 14 and 16. At this time, the cylindrical member 5 is inserted into the through holes formed in the center portions of the first member 2A of the outer cylinder 2, the end plate member 4b of the carrier 4, and the oscillating gears 14 and 16. Furthermore, a part of the cylindrical member 5 is accommodated in the first space A1 of the base 4a of the carrier 4. Thus, the cylindrical member 5 is arranged so that the center axis of the cylindrical member 5 overlaps with the center axis C1 of the axial conversion transmission device X1. For example, a cable, etc. (not shown) is inserted into the cylindrical member 5.

[0035] The transmission gear 6 transmits torque transmitted from the input shaft 20 (described later) to the axial conversion unit 8 to the crankshafts 10. The transmission gear 6 is arranged around the circumference of the cylindrical member 5. The transmission gear 6 is contained in the second space A2 of the main body member 4d of the base 4a.

[0036] The transmitting gear 6 comprises a first gear 6a, a second gear 6b, a first extension element 6c, a second extension element 6d, a connecting element 6b and a projection element 6f.

[0037] The first gear 6a rotates around the central axis C1. The first gear 6a meshes with the shaft gear 10d of the individual crankshafts 10.

[0038] Like the first gear 6a, the second gear 6b ​​also rotates around the central axis C1. The second gear 6b ​​is spaced apart from the first gear 6a in the axial direction of the axial conversion gear device X1. The second gear 6b ​​is located closer to the bottom surface S2 side than the first gear 6a. In other words, the first gear 6a is farther away from the bottom surface S2 in the axial direction of the axial conversion gear device X1 than the second gear 6b. According to the present embodiment, an outer diameter of the second gear 6b ​​is larger than an outer diameter of the first gear 6a.

[0039] Fig. Figure 3 is an axial view of the axial conversion gear device X1, wherein the outer peripheries of the outer cylinder 2, the cylindrical member 5, the shaft gears 10d, and the externally toothed gear 8a are schematically indicated by solid lines, and the outer peripheries of the first gear 6a and the second gear 6b ​​are schematically indicated by dashed lines. In addition, Fig. 3, a shaft gear contact circle O2, whose radius extends from the central axis C1 to the outermost circumference of the shaft gears 10d, is represented by a line broken by two points. In this description, the outermost circumference of the shaft gears 10d represents an outer circumference farthest from the central axis C1 of the shaft gears 10d.

[0040] As in Fig. As shown in Figure 3, an outer diameter of the second gear 6b ​​is smaller than an outer diameter of the shaft gear contact circle O2. In other words, a distance between the center axis C1 and the outermost circumference of the second gear 6b ​​is smaller than a distance between the center axis C1 and the outermost circumference of the shaft gears 10d.

[0041] The first extension member 6c is tubular and extends from an inner peripheral portion of the first gear 6a to the second gear 6b ​​side (in Fig. 1 shown on a lower side) in the axial direction of the axial conversion gear device X1.

[0042] The second extension member 6d is tubular and extends from an inner peripheral portion of the second gear 6b ​​to the side of the first gear 6a (in Fig. 1 shown on an upper side) in the axial direction of the axial conversion gear device X1. An outer diameter of the second extension member 6d is larger than an outer diameter of the first extension member 6c.

[0043] The connecting element 6e connects an end portion opposite the first gear 6a of the first extension element 6c with an end portion opposite the second gear 6b ​​of the second extension element 6d. The connecting element 6e extends in the radial direction of the first gear 6a and the second gear 6b.

[0044] The first projection member 6f protrudes from the inner peripheral portion of the first gear 6a on the opposite side of the second gear 6b ​​(in Fig. 1 shown on the upper side) in the axial direction of the axial conversion gear device X1.

[0045] According to the present embodiment, the first gear 6a, the first extension member 6c, the connecting member 6e, and the projection member 6f are integrally formed. Furthermore, the second gear 6b ​​and the second extension member 6d are integrally formed. The connecting member 6e and the second extension member 6d are fixed to each other by a plurality of screws B3, thus forming the transmission gear 6.

[0046] Between the transmission gear 6 and the carrier 4 is a pair of bearings 7a and 7b, which are spaced apart from each other in the axial direction of the transmission gear 6. Thanks to the bearings 7a and 7b, the transmission gear 6 can rotate relative to the carrier 4 about the central axis C1.

[0047] The bearing 7a is mounted on a mounting surface of the first side member 4f in the axial direction of the main body member 4d. The mounting surface is arranged opposite the projection member 6f in a direction perpendicular to the center axis C1 of the first side member 4f. Thus, the bearing 7a is located between the mounting surface of the first side member 4f and the projection member 6f of the transmission gear 6.

[0048] The bearing 7a is mounted on a mounting member 4h formed on the second side portion 4g in the axial direction of the main body member 4d. The mounting member 4h extends axially into a space formed between the cylindrical member 5 and the second extension member 6d of the transmission gear 6 in the second side portion 4g. Thus, the bearing 7b is located between the mounting member 4h of the second side portion 4g and the second extension member 6d of the transmission gear 6.

[0049] According to the present embodiment, the bearing 7a is located outside the radial direction of the transmission gear 6. Furthermore, the bearing 7b is located inside the radial direction of the transmission gear 6. These bearings 7a and 7b allow the transmission gear 6 to rotate.

[0050] The axial conversion unit 8 converts a torque transmitted from the input shaft 20 (described later) into a torque in the axial direction of the axial conversion gear device X1. The axial conversion unit 8 is arranged in the third space A3 of the main body member 4d of the base 4a.

[0051] The bearings 9a and 9b are arranged between the axial conversion unit 8 and the carrier 4. The first side part 4f has on one side (in Fig. 1 on the upper surface S1) in the axial direction of the third space A3 of the main body element 4d has a mounting element 4i to which the bearing 9a is mounted. The second side part 4g on the other side (in Fig. 1 on the lower surface S2) in the axial direction of the third space A3 of the main body element 4d has a mounting element 4j on which the bearing 9b is mounted. The bearings 9a and 9b, mounted on the mounting elements 4i and 4j, enable the rotation of the axial conversion unit 8 relative to the carrier 4 about the central axis C2. The central axis C2 extends parallel to the central axis C1 of the transmitting gear 6.

[0052] In addition, Fig. 3 an internal tooth contact circle O1, the radius of which is determined by the Fig. 2, extending to the outermost periphery of the inner tooth pins 3, is represented by a line broken by a dot. In the present description, the outermost periphery of the inner tooth pins 3 represents an outer periphery that is furthest from the central axis C1 of the outer peripheries of the inner tooth pins 3.

[0053] As in Fig. As shown in Figure 3, the center axis C2 of the axial conversion unit 8 is located within the internal gear contact circle O1. In other words, a distance between the center axis C1 and the center axis C2 is smaller than a distance between the center axis C1 and the outermost periphery of the internal toothed pins 3.

[0054] The axial conversion unit 8 has the externally toothed gear 8a and an axial conversion gear 8b.

[0055] The externally toothed gear 8a is located closer to the bottom surface S2 side than the axially toothed gear 8b in the axial direction of the axially conversion gear device X1. An outer diameter of the externally toothed gear 8a is smaller than an outer diameter of the axially conversion gear 8b. The externally toothed gear 8a meshes with the second gear 6b ​​of the transmitting gear 6 in the radial direction of the externally toothed gear 8a.

[0056] The axial conversion gear 8b is located closer to the first gear 6a side than the external gear 8a in the axial direction of the axial conversion transmission device X1. According to the present embodiment, the axial conversion gear 8b is composed of a bevel gear. The outer diameter of the axial conversion gear 8b is larger than the outer diameter of the external gear 8. The axial conversion gear 8b is located between the first gear 6a and the second gear 6b ​​in the axial direction of the axial conversion transmission device X1. In addition, an outer peripheral portion 8c of the axial conversion gear 8b has a portion that overlaps with the second gear 6b ​​in the axial direction of the axial conversion transmission device X1.

[0057] The input shaft 20 is, for example, a member to which torque is transmitted from an external motor. The input shaft 20 is arranged in the fourth space A4 formed in the protrusion 4e of the base 4a. The input shaft 20 extends in a direction perpendicular to the axial direction of the axial conversion gear device X1. A pair of bearings 22a and 22b, spaced apart from each other in the axial direction of the input shaft 20, are arranged between the input shaft 20 and the protrusion 4e. Thanks to the bearings 22a and 22b, the input shaft 20 can rotate relative to the carrier 4 about the central axis C3.

[0058] The input shaft 20 has an input gear 20a and an input opening 20b.

[0059] The input gear 20a is arranged at one end portion of the input shaft 20. According to the present embodiment, the input gear 20a is composed of a bevel gear. The input gear 20a meshes with the axial conversion gear 8b of the axial conversion unit 8 through the third space A3 open on a side surface of the main body member 4d of the base 4a.

[0060] The input port 20b, for example, is a port into which an output shaft of an external motor is inserted. The torque of the output shaft of the external motor is transmitted through the input port 20b to the input shaft 20 in a direction perpendicular to the axial direction of the axial conversion gear device X1. This causes the input shaft 20 to rotate around the central axis C3.

[0061] In the axial conversion gear device X1 having the above-described structure, for example, the input torque of an external motor causes the input shaft 20 to rotate about the central axis C3. As the axial conversion gear 8b rotates in mesh with the input gear 20a, the external gear 8a rotates about the central axis C2. Thus, the input torque about the central axis C3 is converted into a torque about the central axis C2. The transmitting gear 6, in which the second gear 6b ​​meshes with the external gear 8a, rotates about the central axis C1. Thus, the wave gears 10d meshing with the first gear 6a rotate. As the wave gears 10d rotate, the eccentric parts 10a and 10b rotate eccentrically, and the oscillating gears 14 and 16 oscillate and rotate.The first oscillating gear 14 and the second oscillating gear 16, which mesh with the inner pins 3, rotate while the meshing points shift. Thus, the outer cylinder 2 and the carrier 4 rotate relatively around the central axis C1.

[0062] As described above, in the axial conversion gear device X1, the axial conversion gear 8b is located closer to the first gear 6a side in the axial direction of the axial conversion gear device X1 than the externally toothed gear 8a. Thus, the externally toothed gear 8a can be arranged in the dead space existing between the axial conversion gear 8b and the bottom surface S2 in the axial direction of the axial conversion gear device X1. This can effectively utilize the dead space and prevent the axial conversion gear device X1 from becoming excessively large in the axial direction. In addition, the axial conversion gear 8b is arranged between the first gear 6a and the second gear 6b ​​in the axial direction of the axial conversion gear device X1. Thus, there is no radial obstruction of the first gear 6a and the shaft gears 10d, which are in engagement with the first gear 6, by the axial conversion gear 8b.As a result, the center axis C1 of the transmitting gear 6 can be arranged close to the center axis C2 of the axial conversion unit 8 in the radial direction of the axial conversion gear device X1. Consequently, the axial conversion gear device X1 can be made radially small.

[0063] Furthermore, in the axial conversion gear device X1, the outer diameter of the externally toothed gear 8a is smaller than the outer diameter of the axial conversion gear 8b. In the axial conversion unit 8, the outer peripheral portion 8c of the axial conversion gear 8b overlaps with the second gear 6b ​​in the axial direction of the axial conversion gear device X1. Thus, since the center axis C1 of the transmitting gear 6 in the radial direction of the axial conversion gear device X1 is located close to the center axis C2 of the axial conversion unit 8, the axial conversion gear device X1 can be downsized in the radial direction.

[0064] In the axial conversion gear device X1, the outer diameter of the second gear 6b ​​is smaller than the outer diameter of the shaft gear contact circle O2. Thus, the axial conversion unit 8, whose externally toothed gear 8a meshes with the second gear 6b, can be arranged near the center axis C1 of the transmitting gear 6. Consequently, the axial conversion gear device X1 can be designed to be radially small.

[0065] In the axial conversion gear device X1, the center axis C2 of the axial conversion unit 8 is located within the internal gear contact circle O1. This prevents the main body element 4d of the carrier 4, which supports the axial conversion unit 8, from becoming radially excessive.

[0066] As those skilled in the art will appreciate, the present embodiment is merely a non-limiting example. The scope of the present invention is determined by the appended claims, not by the description of the aforementioned embodiment. Furthermore, numerous modifications, combinations, sub-combinations, and alternatives are possible within the scope of the appended claims or their equivalents.

[0067] For example, in the axial conversion gear device X1 according to the present embodiment, the center axis C3 of the input shaft 20 intersects the center axis C2 of the axial conversion unit 8. Thus, the torque is converted orthogonally. Alternatively, the axial conversion unit 8 can also convert torque transmitted from a direction other than the axial direction of the axial conversion unit 8 into the axial direction.

[0068] In the axial conversion gear device X1 according to the present embodiment, the input gear 20a and the axial conversion gear 8b are bevel gears. Alternatively, the input gear 20a and the axial conversion gear 8b need not be bevel gears, as long as the axial conversion unit 8 can convert one axial direction of the input torque to another axial direction.

[0069] In the axial conversion gear device X1 according to the present embodiment, a plurality of crankshafts 10 are arranged, and a transmission gear 6 is engaged with a plurality of shaft gears 10d. Alternatively, only one crankshaft 10 may be arranged. In this case, a transmission gear 6 is engaged with a shaft gear 10d.

[0070] In the axial conversion gear device X1 according to the present embodiment, the transmitting gear 6 is a hollow member, and the cylindrical member 5 is inserted into the hollow space of the transmitting gear 6. If the cylindrical member 5 is not provided, the transmitting gear 6 does not need to be a hollow member.

[0071] In the axial conversion gear device X1 according to the present embodiment, the outer cylinder 2 is a rotation-side member of the axial conversion gear device X1, while the carrier 4 is a fixed side member of the axial conversion gear device X1. Alternatively, the outer cylinder 2 may be a fixed side member of the axial conversion gear device X1, while the carrier 4 is a rotation-side member of the axial conversion gear device X1. In this case, the first member 2A of the outer cylinder 2 forms the bottom surface S2 of the axial conversion gear device X1, while the base 4a of the carrier 4 forms the top surface S1 of the axial conversion gear device X1.

[0072] It should be noted that the specific embodiment described above includes an invention having the following configurations.

[0073] The axial conversion gear device according to the present invention has the following configurations: a crankshaft having a shaft main body, an eccentric part eccentric to the shaft main body, and a shaft gear arranged on the shaft main body; an oscillating gear having a plurality of external teeth and oscillating and rotating due to the rotation of the eccentric part; a transmitting gear having a first gear meshing with the shaft gear of the crankshaft and a second gear spaced apart from the first gear in an axial direction of the first gear; an axial conversion unit having an externally toothed gear meshing with the second gear and an axial conversion gear that converts the input torque into torque in an axial direction of the externally toothed gear;and an outer cylinder having a plurality of internal teeth each meshing with the external teeth of the oscillating gear, wherein the axial conversion gear is arranged between the first gear and the second gear in the axial direction of the externally toothed gear;

[0074] In the above axial conversion gear device, the axial conversion gear is located closer to the first gear side than the external gear. Thus, the external gear of the axial conversion unit is located in the area corresponding to the dead space found in the gear transmission device described in Japanese Patent Unexamined Publication No. 2010101366. This can prevent the axial conversion gear device from becoming excessively large in the axial direction. Furthermore, in the axial conversion gear device, the axial conversion gear is located between the first gear and the second gear in the axial direction of the external gear. As a result, the axial conversion gear does not interfere with the first gear and the axial gear meshing with the first gear in the radial direction of the external gear.This allows the center axis of the transmitting gear to be positioned close to the center axis of the axial conversion unit in the radial direction of the external gear. Consequently, the axial conversion transmission device can be designed to be radially small.

[0075] An outer diameter of the externally toothed gear is preferably smaller than an outer diameter of the axial conversion gear. In the axial conversion unit, a part of the outer peripheral portion of the axial conversion gear preferably overlaps with the second gear in the axial direction of the externally toothed gear.

[0076] Furthermore, in the aforementioned axial conversion gear device, the axial conversion gear is located between the first gear and the second gear in the axial direction of the external gear. Since the outer diameter of the external gear is smaller than the outer diameter of the axial conversion gear, the outer peripheral portion of the axial conversion gear and the second gear can be arranged so that the outer peripheral portion and the second gear overlap each other. This minimizes the distance between the center axis of the transmitting gear and the center axis of the axial conversion gear. Consequently, the axial conversion gear device can be designed to be radially small.

[0077] An outer diameter of the second gear is preferably smaller than a diameter of a shaft gear contact circle whose radius extends from a center axis of the transmitting gear to an outermost circumference of the shaft gear.

[0078] In the aforementioned axial conversion gear device, the outer diameter of the second gear is smaller than the diameter of the shaft gear contact circle. Since the outer diameter of the second gear can be reduced, the axial conversion unit, whose external gear meshes with the second gear, can be arranged closer to the center axis of the transmitting gear. Consequently, the axial conversion gear device can be designed to be radially small.

[0079] The axial conversion gear device preferably further includes a carrier that rotatably supports the crankshaft, the transmitting gear, and the axial conversion unit, and rotates relative to the outer cylinder about the center axis of the transmitting gear due to the oscillation and rotation of the oscillating gear. A center axis of the axial conversion unit is preferably arranged in an internal gear contact circle whose radius extends from the center axis of the transmitting gear to an outermost periphery of the internal teeth.

[0080] Since the aforementioned axial conversion gear device minimizes the distance between the center axis of the transmitting gear and the center axis of the axial conversion unit, the center axis of the axial conversion unit can be positioned within the internal gear contact circle. Consequently, the carrier supporting the axial conversion unit can be prevented from becoming radially excessive.

[0081] This application is based on JP 2015-215034 A, the contents of which are incorporated herein by reference in their entirety.

[0082] While the present invention has been fully described by way of example with reference to the accompanying drawings, it will be apparent to those skilled in the art that various changes and modifications may be made. Thus, unless such changes and modifications depart from the scope of the present invention, they are to be construed as included therein.

Claims

[1] Axial conversion gear device (X1), comprising: at least one crankshaft (10) having a shaft main body (10c), an eccentric part (10a, 10b) which is eccentric to the main shaft body (10c), and a shaft gear (10b) which is arranged on the shaft main body (10c); an eccentrically rotating gear (14, 16) having a plurality of external teeth (14a, 16a) which is caused to rotate eccentrically due to the rotation of the eccentric part (10a, 10b); a transmitting gear shaft (6) having a first gear (6a) meshing with the shaft gear (10d) of the crankshaft (10) and a second gear (6b) spaced apart from the first gear (6a) in an axial direction of the first gear (6a); an axial conversion unit (8) having an externally toothed gear (8a) meshing with the second gear (6b) and an axial conversion gear (8b) converting an input torque applied to an input shaft (20) into a torque in an axial direction of the externally toothed gear (8a); and an outer cylinder (2) having a plurality of internal teeth (3) which mesh with the external teeth (14a, 16a) of the eccentrically rotating gear (14, 16), wherein the axial conversion gear (8b) is arranged in the axial direction of the externally toothed gear (8a) between the first gear (6a) and the second gear (6b). [2] Axial conversion gear device (X1) according to claim 1, wherein an outer diameter of the externally toothed gear (8a) is smaller than an outer diameter of the axial conversion gear (8b), and the axial conversion unit (8) is arranged such that a part of an outer peripheral portion (8c) of the axial conversion gear (8b) overlaps with the second gear (6b) in the axial direction of the externally toothed gear (8a). [3] The axial conversion gear device (X1) according to claim 1 or 2, wherein an outer diameter of the second gear (6b) is smaller than a diameter of a shaft gear contact circle (O2) whose radius ranges from a center axis (C1) of the transmitting gear shaft (6) to an outermost circumference of the shaft gear (10d). [4] Axial conversion gear device (X1) according to one of claims 1 to 3, further comprising: a carrier (4) which rotatably supports the crankshaft (10), the transmitting gear shaft (6) and the axial conversion unit (8) and rotates relative to the outer cylinder (2) about the central axis (C1) of the transmitting gear shaft (6) due to the eccentrically rotating gear (14, 16), wherein a central axis (C2) of the axial conversion unit (8) is arranged in an internal toothing contact circle (O1) whose radius extends from the central axis (C1) of the transmitting gear shaft (6) to an outermost circumference of the internal teeth (3).

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