JP2019203604A - Group of speed reducer, speed reducer and method for designing speed reducer - Google Patents

Abstract

To provide a technology capable of manufacturing a speed reducer under application of a small number of types of bearing.SOLUTION: This patent application discloses a group of speed reducer comprising: a first speed reducer having a first crank assembly for oscillating a first oscillation gear to rotate a first output part around a first main shaft by performing a rotating motion around a first transmitting shaft spaced apart by a first distance only from the first main shaft defined as a rotating central shaft of the first output part; and a second speed reducer having a second crank assembly for oscillating a second oscillation gear to rotate a second output part around a second main shaft by performing a rotating motion around a second transmitting shaft spaced apart by a second distance only different from the first distance from the second main shaft defined as a rotating central shaft of the second output part.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to a reduction gear having a mechanism as an eccentric oscillating gear device.

  Various speed reducers are used in various technical fields such as industrial robots and machine tools (see Patent Document 1). Patent Document 1 discloses a reduction gear including a cylindrical casing, a swing gear that swings within the casing, and a crank assembly that swings the swing gear. Based on the technology disclosed in Patent Document 1, the designer can design various reduction gears so as to meet the performance required by the customer (for example, torque and reduction ratio).

JP 2010-286098 A

  According to Patent Document 1, the crank assembly includes a number of bearings. If the designer designs different reducers according to different customer requirements, the management effort of the logistics department managing the production of reducers can be excessive due to too many bearing types There is also.

  It is an object of the present invention to provide a technique that enables the production of a reduction gear under the use of a small number of types of bearings.

  The reduction gear group according to one aspect of the present invention performs the rotational motion around the first transmission shaft that is separated from the first main shaft that is defined as the rotation center axis of the first output portion by a first distance. A first speed reducer having a first crank assembly for oscillating a first oscillating gear so as to rotate the first output part around the main axis, and a second main axis defined as a rotation center axis of the second output part The second oscillating gear is oscillated so as to rotate the second output portion around the second main shaft by performing a rotational movement around the second transmission shaft separated from the first distance by a second distance different from the first distance. A second reduction gear having a second crank assembly to be moved. The first crank assembly includes a first crankshaft including a first journal and a first eccentric portion eccentric with respect to the first journal; a first shaft support bearing attached to the first journal; A first gear support bearing disposed between the one eccentric portion and the first swing gear. The second crank assembly includes a second crankshaft including a second journal and a second eccentric portion eccentric with respect to the second journal, a second shaft support bearing attached to the second journal, and the second crankshaft. And a second gear support bearing disposed between the second eccentric portion and the second oscillating gear. The first gear support bearing conforms in shape to the second shaft support bearing.

  According to the above configuration, the first gear support bearing conforms in shape to the second shaft support bearing, so that the bearing can be used for each of the first reduction gear and the second reduction gear. Accordingly, the first reducer and the second reducer are manufactured using a small number of types of bearings.

  In the above configuration, each of the first shaft support bearing, the first gear support bearing, the second shaft support bearing, and the second gear support bearing may be a needle bearing.

  According to the above configuration, since the needle bearing is used for the first shaft support bearing, the first gear support bearing, the second shaft support bearing, and the second gear support bearing, the bearing prepared for supporting the gear is It can also be used as a bearing for supporting the crankshaft.

  In the above configuration, the first shaft support bearing may be different in shape from the first gear support bearing. The second shaft support bearing may be different in shape from the second gear support bearing.

  According to the above configuration, the first shaft support bearing is different in shape from the first gear support bearing. Therefore, the designer who designs the first crank assembly can respond to the conditions required for the first reduction gear. Thus, the diameter ratio between the first journal and the first eccentric portion can be set appropriately. Since the second shaft support bearing is different in shape from the second gear support bearing, the designer who designs the second crank assembly can change the second journal according to the conditions required for the second reduction gear. The diameter ratio between the second eccentric portion and the second eccentric portion can be set appropriately.

  A reduction gear according to another aspect of the present invention is a distance relationship between a rotation center axis of an output part and a transmission rotation axis of a crank assembly that transmits a driving force for rotating the output part around the rotation center axis. This is different from other reduction gears. The speed reducer includes a first output portion that rotates around a first main axis that is defined as the rotation center axis, and a first swing gear that swings to cause rotation of the first output portion around the first main shaft. And a first crank assembly that performs a rotational motion around the first transmission shaft defined as the transmission rotation shaft that is spaced apart from the first main shaft by a first distance. The other another speed reducer rotates around a second transmission shaft defined as the transmission rotation shaft separated from the second main shaft defined as the rotation center axis by a second distance different from the first distance. A second crank assembly that swings the second swing gear so as to rotate the second output portion around the second main shaft by performing the movement is provided. The first crank assembly includes a first crankshaft including a first journal and a first eccentric portion eccentric with respect to the first journal; a first shaft support bearing attached to the first journal; A first gear support bearing disposed between the one eccentric portion and the first swing gear. The second crank assembly includes a second crankshaft including a second journal and a second eccentric portion eccentric with respect to the second journal, a second shaft support bearing attached to the second journal, and the second crankshaft. And a second gear support bearing disposed between the second eccentric portion and the second oscillating gear. The first gear support bearing conforms in shape to the second shaft support bearing.

  According to the above configuration, the first gear support bearing conforms in shape to the second shaft support bearing, so that the bearing can be used for each of the first reduction gear and the second reduction gear. Accordingly, the first reducer and the second reducer are manufactured using a small number of types of bearings.

  A design method according to still another aspect of the present invention is a distance relationship between a rotation center axis of an output unit and a transmission rotation axis of a crank assembly that transmits a driving force for rotating the output unit around the rotation center axis. Is used for the design of a speed reducer that is different from another speed reducer. The design method includes a step of designing a first output unit that rotates about a first main axis defined as the rotation center axis, and a first swinging unit that causes the first output unit to rotate about the first main axis. Designing a single oscillating gear; designing a first crank assembly that performs rotational movement about a first transmission shaft defined as the transmission rotation shaft spaced from the first main shaft by a first distance; Is provided. The other another speed reducer rotates around a second transmission shaft defined as the transmission rotation shaft separated from the second main shaft defined as the rotation center axis by a second distance different from the first distance. A second crank assembly that swings the second swing gear so as to rotate the second output portion around the second main shaft by performing the movement is provided. The second crank assembly includes a second crankshaft including a second journal and a second eccentric portion eccentric with respect to the second journal, a second shaft support bearing attached to the second journal, and the second crankshaft. And a second gear support bearing disposed between the second eccentric portion and the second oscillating gear. The step of designing the first crank assembly includes: (i) designing a first crankshaft including a first journal and a first eccentric portion eccentric with respect to the first journal; and (ii) the first Determining to use a bearing that conforms in shape to a two-shaft support bearing as a first gear support bearing disposed between the first eccentric portion and the first swing gear.

  According to the above configuration, the design method is such that the first gear support bearing disposed between the first eccentric portion and the first oscillating gear conforms in shape to the second shaft support bearing. Since the step of designing the gear support bearing is included, the bearing can be used for each of the first reduction gear and the second reduction gear. Accordingly, the first reducer and the second reducer are manufactured using a small number of types of bearings.

  The present invention allows the production of a reducer under the use of a small number of bearings.

It is a schematic sectional drawing of the reduction gear of 1st Embodiment. FIG. 1B is a schematic cross-sectional view of the speed reducer along the line AA shown in FIG. 1A. It is a schematic sectional drawing of another reduction gear. It is a table | surface which shows a bearing selection pattern (2nd Embodiment). It is a design conceptual diagram of a crank assembly (third embodiment). It is a conceptual diagram which shows the example design procedure of a reduction gear (4th Embodiment).

  With reference to the accompanying drawings, various embodiments will be described that relate to techniques that enable the manufacture of reducers under the use of a small number of bearings.

<First Embodiment>
In a conventional design technique, a designer has a plurality of reduction gears that are different from each other in a distance relationship between a rotation center axis of an output unit that rotates at a predetermined reduction ratio and a crank assembly that transmits driving force to the output unit. When designing the machine, the designer uses different bearings for each reducer. In the first embodiment, a technique for making a shape-matching bearing available to a plurality of speed reducers will be described.

(Reduction gear structure)
1A and 1B show an exemplary speed reducer 100. FIG. FIG. 1A is a schematic cross-sectional view of the speed reducer 100. FIG. 1B is a schematic cross-sectional view of the speed reducer 100 along the line AA shown in FIG. 1A. The speed reducer 100 will be described with reference to FIGS. 1A and 1B.

  The speed reducer 100 includes a housing cylinder 200, a gear unit 300, and three crank assemblies 400. The housing cylinder 200 accommodates the gear unit 300 and the three crank assemblies 400. In the present embodiment, the first speed reducer is exemplified by the speed reducer 100.

  The housing cylinder 200 includes an outer cylinder part 210, a carrier part 220, and two main bearings 230. The carrier part 220 is disposed in the outer cylinder part 210. The two main bearings 230 are disposed between the outer cylinder part 210 and the carrier part 220. The two main bearings 230 allow relative rotational movement between the outer cylinder part 210 and the carrier part 220. In the present embodiment, the first output part is exemplified by one of the outer cylinder part 210 and the carrier part 220.

  FIG. 1A shows a main shaft FMX defined as the rotation center axis of two main bearings 230. If the outer cylinder part 210 is fixed, the carrier part 220 rotates around the main axis FMX. If carrier part 220 is fixed, outer cylinder part 210 rotates around main axis FMX. That is, one of the outer cylinder part 210 and the carrier part 220 can rotate around the main axis FMX relative to the other of the outer cylinder part 210 and the carrier part 220. In the present embodiment, the first main axis is exemplified by the main axis FMX.

  The designer can give the outer cylinder part 210 various shapes. Therefore, the principle of the present embodiment is not limited to a specific shape of the outer cylinder part 210.

  The designer can give the carrier portion 220 various shapes. Therefore, the principle of this embodiment is not limited to a specific shape of the carrier part 220.

  The outer cylinder part 210 includes an outer cylinder 211 and a plurality of internal tooth pins 212. The outer cylinder 211 defines a cylindrical internal space in which the carrier part 220, the gear part 300, and the crank assembly 400 are accommodated. Each internal tooth pin 212 is a cylindrical member extending substantially parallel to the main shaft FMX. Each internal tooth pin 212 is fitted into a groove formed in the inner wall of the outer cylinder 211. Therefore, each internal tooth pin 212 is appropriately held by the outer cylinder 211.

  The plurality of internal teeth pins 212 are arranged at substantially constant intervals around the main axis FMX. A half circumferential surface of each internal tooth pin 212 protrudes from the inner wall of the outer cylinder 211 toward the main shaft FMX. Therefore, the plurality of internal teeth pins 212 function as internal teeth that mesh with the gear portion 300.

  The carrier part 220 includes a base part 221, an end plate part 222, positioning pins 223, and fixing bolts 224. The carrier part 220 has a cylindrical shape as a whole. The base part 221 includes a substrate part 225 and three shaft parts 226. Each of the three shaft portions 226 extends from the substrate portion 225 toward the end plate portion 222. A screw hole 227 and a reamer hole 228 are formed in the tip surface of each of the three shaft portions 226. The positioning pin 223 is inserted into the reamer hole 228. As a result, the end plate portion 222 is accurately positioned with respect to the base portion 221. The fixing bolt 224 is screwed into the screw hole 227. As a result, the end plate part 222 is appropriately fixed to the base part 221.

  The gear unit 300 is disposed between the substrate unit 225 and the end plate unit 222. The three shaft portions 226 penetrate the gear portion 300 and are connected to the end plate portion 222.

  The gear unit 300 includes two gears 310 and 320. The gear 310 is disposed between the substrate unit 225 and the gear 320. The gear 320 is disposed between the end plate portion 222 and the gear 310.

  The gear 310 is substantially equal to the gear 320 in shape and size. The gears 310 and 320 rotate around the outer cylinder 211 while meshing with the inner tooth pins 212. Therefore, the centers of the gears 310 and 320 go around the main axis FMX. In the present embodiment, the first oscillating gear is exemplified by one of the gears 310 and 320.

  The rotation phase of the gear 310 is shifted from the rotation phase of the gear 320 by approximately 180 °. While the gear 310 meshes with half of the plurality of internal teeth pins 212 of the outer cylinder portion 210, the gear 320 meshes with the remaining half of the plurality of internal teeth pins 212. Therefore, the gear part 300 can rotate the outer cylinder part 210 or the carrier part 220.

  In the present embodiment, the gear unit 300 includes two gears 310 and 320. Alternatively, the designer may use more than two gears as the gear portion. Further alternatively, the designer may use one gear as the gear portion.

  Each of the three crank assemblies 400 includes a crankshaft 410, four bearings 421, 422, 423, 424, and a transmission gear 430. The transmission gear 430 may be a general spur gear. The principle of this embodiment is not limited to a specific type of transmission gear 430.

  The transmission gear 430 directly or indirectly receives a driving force generated by a driving source (for example, a motor). The designer may appropriately set the transmission path of the driving force from the driving source to the transmission gear 430 according to the usage environment and usage conditions of the reduction gear 100. Therefore, the principle of this embodiment is not limited to a specific drive transmission path from the drive source to the transmission gear 430.

  FIG. 1A shows the transmission shaft FTX. The transmission shaft FTX is substantially parallel to the main shaft FMX. The crankshaft 410 rotates around the transmission shaft FTX. FIG. 1A shows the distance between the transmission shaft FTX and the main shaft FMX with the symbol “L1”. In the present embodiment, the first crank assembly is illustrated by one of the three crank assemblies 400. The first transmission shaft is exemplified by the transmission shaft FTX. The first distance is exemplified by the distance L1.

  The crankshaft 410 includes two journals 411 and 412 and two eccentric portions 413 and 414. The journals 411 and 412 extend along the transmission axis FTX. The central axes of the journals 411 and 412 coincide with the transmission axis FTX. The eccentric parts 413 and 414 are formed between the journals 411 and 412. Each of the eccentric portions 413 and 414 is eccentric from the transmission shaft FTX. In the present embodiment, the first crankshaft is exemplified by the crankshaft 410. The first journal is exemplified by one of the journals 411 and 412. The first eccentric portion is exemplified by one of the eccentric portions 413 and 414.

  The journal 411 is inserted into the bearing 421. The bearing 421 is disposed between the journal 411 and the end plate portion 222. Therefore, the journal 411 is supported by the end plate portion 222 and the bearing 421. The journal 412 is inserted into the bearing 422. The bearing 422 is disposed between the journal 412 and the base 221. Therefore, the journal 412 is supported by the base 221 and the bearing 422. In the present embodiment, the first shaft support bearing is exemplified by one of the bearings 421 and 422.

  The eccentric part 413 is inserted into the bearing 423. The bearing 423 is disposed between the eccentric portion 413 and the gear 310. The eccentric part 414 is inserted into the bearing 424. The bearing 424 is disposed between the eccentric portion 414 and the gear 320. In the present embodiment, the first gear support bearing is exemplified by one of the bearings 423 and 424.

  When a driving force is input to the transmission gear 430, the crankshaft 410 rotates around the transmission axis FTX. As a result, the eccentric portions 413 and 414 rotate eccentrically around the transmission shaft FTX. The gears 310 and 320 connected to the eccentric parts 413 and 414 via the bearings 423 and 424 oscillate in a circular space defined by the outer cylinder part 210. Since the gears 310 and 320 mesh with the inner tooth pin 212, a relative rotational motion is caused between the outer cylinder part 210 and the carrier part 220.

(Another reduction gear)
Based on the design principle of the speed reducer 100 described with reference to FIGS. 1A and 1B, the designer can design another speed reducer that is different in dimension.

  FIG. 2 shows another reduction gear 100A constructed based on the design principle described with reference to FIGS. 1A and 1B. FIG. 2 is a schematic cross-sectional view of the speed reducer 100A. A reduction gear 100A will be described with reference to FIGS. 1A and 2.

  The speed reducer 100A includes a casing cylinder 200A, a gear portion 300A, and a crank assembly 400A. The casing cylinder 200A accommodates the gear portion 300A and the crank assembly 400A. In the present embodiment, the second speed reducer is exemplified by a speed reducer 100A.

  The housing cylinder 200A includes an outer cylinder part 210A, a carrier part 220A, and two main bearings 230A. The carrier part 220A is disposed in the outer cylinder part 210A. The two main bearings 230A are arranged between the outer cylinder part 210A and the carrier part 220A. The two main bearings 230A allow relative rotational movement between the outer cylinder part 210A and the carrier part 220A. In the present embodiment, the second output part is exemplified by one of the outer cylinder part 210A and the carrier part 220A.

  FIG. 2 shows the main shaft SMX defined as the rotation center axis of the two main bearings 230A. If outer cylinder part 210A is fixed, carrier part 220A rotates around main axis SMX. If carrier part 220A is fixed, outer cylinder part 210A rotates around main axis SMX. That is, one of the outer cylinder part 210A and the carrier part 220A can be rotated around the main axis SMX relative to the other of the outer cylinder part 210A and the carrier part 220A. In the present embodiment, the second main axis is exemplified by the main axis SMX.

  The designer can give various shapes to the outer cylindrical portion 210A. Therefore, the principle of the present embodiment is not limited to a specific shape of the outer cylinder portion 210A.

  The designer can give various shapes to the carrier part 220A. Therefore, the principle of this embodiment is not limited to a specific shape of the carrier portion 220A.

  The outer cylinder portion 210A includes an outer cylinder 211A and a plurality of internal tooth pins 212A. There may be more internal tooth pins 212A in the speed reducer 100A than the internal tooth pins 212 in the speed reducer 100. The outer cylinder 211A defines a cylindrical inner space in which the carrier part 220A, the gear part 300A, and the crank assembly 400A are accommodated. Each internal tooth pin 212A is a cylindrical member extending substantially parallel to the main shaft SMX. Each internal tooth pin 212A is fitted into a groove formed on the inner wall of the outer cylinder 211A. Therefore, each internal tooth pin 212A is appropriately held by the outer cylinder 211A.

  The plurality of internal teeth pins 212A are arranged at substantially constant intervals around the main axis SMX. The half circumferential surface of each internal tooth pin 212A protrudes from the inner wall of the outer cylinder 211A toward the main shaft SMX. Accordingly, the plurality of internal teeth pins 212A function as internal teeth that mesh with the gear portion 300A.

  The carrier portion 220A includes a base portion 221A and an end plate portion 222A. The carrier part 220A has a cylindrical shape as a whole. The base portion 221A includes a substrate portion 225A and a shaft portion 226A. The shaft portion 226A extends from the substrate portion 225A toward the end plate portion 222A. Similarly to the speed reducer 100A, the end plate portion 222A may be fixed to the distal end surface of the shaft portion 226A with screws and pins.

  The gear portion 300A is disposed between the substrate portion 225A and the end plate portion 222A. The shaft portion 226A passes through the gear portion 300A and is connected to the end plate portion 222A.

  The gear unit 300A includes two gears 310A and 320A. The gear 310A is disposed between the board portion 225A and the gear 320A. The gear 320A is disposed between the end plate portion 222A and the gear 310A.

  The gear 310A is similar to the gear 320A in shape and size. The gears 310A and 320A move around the outer cylinder 211A while meshing with the inner tooth pins 212A. Therefore, the centers of the gears 310A and 320A go around the main axis SMX. In the present embodiment, the second rocking gear is exemplified by one of the gears 310A and 320A.

  The rotation phase of the gear 310A is shifted by approximately 180 ° from the rotation phase of the gear 320A. While the gear 310A meshes with half of the plurality of internal teeth pins 212A of the outer cylinder portion 210A, the gear 320A meshes with the remaining half of the plurality of internal teeth pins 212A. Therefore, the gear part 300A can rotate the outer cylinder part 210A or the carrier part 220A.

  In the present embodiment, the gear unit 300A includes two gears 310A and 320A. Alternatively, the designer may use more than two gears as the gear portion. Further alternatively, the designer may use one gear as the gear portion.

  The crank assembly 400A includes a crankshaft 410A, four bearings 421A, 422A, 423A, and 424A, and a transmission gear 430A. The transmission gear 430A may be a general spur gear. The principle of this embodiment is not limited to a specific type of transmission gear 430A.

  FIG. 2 shows the transmission shaft STX. The transmission axis STX is substantially parallel to the main axis SMX. The crankshaft 410A rotates around the transmission shaft STX. FIG. 2 shows the distance between the transmission shaft STX and the main shaft SMX with the symbol “L2”. The distance L2 is larger than the distance L1. In the present embodiment, the second crank assembly is exemplified by the crank assembly 400A. The second transmission shaft is exemplified by the transmission shaft STX. The second distance is exemplified by the distance L2.

  The crankshaft 410A includes two journals 411A and 412A and two eccentric portions 413A and 414A. The journals 411A and 412A extend along the transmission axis STX. The central axes of the journals 411A and 412A coincide with the transmission axis STX. The eccentric portions 413A and 414A are formed between the journals 411A and 412A. Each of the eccentric portions 413A and 414A is eccentric from the transmission shaft STX. In the present embodiment, the second crankshaft is exemplified by the crankshaft 410A. The second journal is exemplified by one of the journals 411A and 412A. The second eccentric portion is exemplified by one of the eccentric portions 413A and 414A.

  The journal 411A is inserted into the bearing 421A. The bearing 421A is disposed between the journal 411A and the end plate portion 222A. Therefore, the journal 411A is supported by the end plate portion 222A and the bearing 421A. The journal 412A is inserted into the bearing 422A. The bearing 422A is disposed between the journal 412A and the base 221A. Therefore, the journal 412A is supported by the base 221A and the bearing 422A. In the present embodiment, the second shaft support bearing is exemplified by one of the bearings 421A and 422A.

  The eccentric portion 413A is inserted into the bearing 423A. The bearing 423A is disposed between the eccentric portion 413A and the gear 310A. The eccentric portion 414A is inserted into the bearing 424A. The bearing 424A is disposed between the eccentric portion 414A and the gear 320A. In the present embodiment, the second gear support bearing is exemplified by one of the bearings 423A and 424A.

  When driving force is input to the transmission gear 430A, the crankshaft 410A rotates around the transmission shaft STX. As a result, the eccentric portions 413A and 414A rotate eccentrically around the transmission shaft STX. The gears 310A and 320A connected to the eccentric portions 413A and 414A via the bearings 423A and 424A swing within a circular space defined by the outer cylinder portion 210A. Since the gears 310A and 320A mesh with the internal tooth pin 212A, a relative rotational motion is caused between the outer cylinder portion 210A and the carrier portion 220A.

  The designer may select a bearing that conforms in shape to the bearings 423 and 424 of the speed reducer 100 as the bearings 421A and 422A of the speed reducer 100A.

Second Embodiment
The designer may select a bearing to be used for the speed reducer based on a model number given by a supplier supplying the bearing. In the second embodiment, various bearing selection patterns are described.

  FIG. 3 is a table showing bearing selection patterns for the speed reducers 100 and 100A. The bearing selection pattern will be described with reference to FIGS. 1A, 2 and 3.

  In this embodiment, the supplier attaches model numbers “NDL-1”, “NDL-2”, and “NDL-3” to the needle bearings. A plurality of bearings with the same model number have substantially the same shape and substantially the same performance. On the other hand, a plurality of bearings with different model numbers have different shapes (for example, different inner diameter dimensions, different outer dimensions and / or different thickness dimensions) and different performances. Have.

  The phrase “the plurality of bearings are geometrically equal” does not mean that the actual shapes of the plurality of bearings completely match. Even if a manufacturing error of a plurality of bearings causes a minute error in the dimensions of the plurality of bearings, the plurality of bearings are included in the concept of bearings having the same shape. For example, if multiple bearings are built based on a common design drawing, these bearings are geometrically equivalent (ie, multiple bearings are equal in inner diameter dimension, outer dimension, thickness, and other dimensions) ).

  The phrase “several bearings are equal in performance” does not only mean that the actual performance of the plurality of bearings is a perfect match. Even if there is a slight difference in the performance actually exhibited by the plurality of bearings, the plurality of bearings are included in the concept of bearings that are equal in performance. For example, if multiple bearings are built based on a common design drawing, these bearings are equal in performance (for example, multiple bearings are subject to allowable loads and other performance parameters). ,equal).

  FIG. 3 shows that the designer has selected a needle bearing with the model number “NDL-1” for the bearings 421 and 422. Since the needle bearings with the model number “NDL-1” are used as the bearings 421 and 422, the bearings 421 and 422 are equal in shape and performance.

  FIG. 3 shows that the designer has selected a needle bearing with the model number “NDL-2” for the bearings 423, 424, 421 A, and 422 A. Since the needle bearing with the model number “NDL-2” is used as the bearings 423, 424, 421A, 422A, the bearings 423, 424, 421A, 422A are equal in shape and performance.

  FIG. 3 shows that the designer has selected a needle bearing with the model number “NDL-3” for the bearings 423A and 424A. Since the needle bearing with the model number “NDL-3” is used as the bearings 423A and 424A, the bearings 423A and 424A are equal in shape and performance.

<Third Embodiment>
The designer can change the distance between the main shaft and the transmission shaft and set various values for the torque that can be output by the reduction gear. If a large torque is required for the reduction gear, the designer may increase the distance between the main shaft and the transmission shaft. In this case, the designer may incorporate a thick crankshaft into the speed reducer so that the speed reducer has sufficient mechanical strength. The design principles described in connection with the first and second embodiments make it possible to assemble a crank assembly by attaching a small number of bearings to crankshafts that differ in thickness. In the third embodiment, a technique for constructing various crank assemblies having different thicknesses by using a small number of bearings will be described.

  FIG. 4 is a design conceptual diagram of the crank assembly. The design concept of the crank assembly is described with reference to FIG.

  FIG. 4 shows three crank assemblies 400B, 400C, 400D. The crank assemblies 400B, 400C, and 400D are different from each other in thickness.

  The crank assembly 400B includes a crankshaft 410B and four needle bearings 421B, 422B, 423B, and 424B. The crankshaft 410B includes two journals 411B and 412B and two eccentric portions 413B and 414B. The eccentric portions 413B and 414B are formed between the journals 411B and 412B. The journals 411B and 412B are coaxial, while the eccentric portions 413B and 414B are different axes. The eccentric portions 413B and 414B are eccentric with respect to the journals 411B and 412B, respectively. The eccentric portions 413B and 414B are thicker than the journals 411B and 412B, respectively. Needle bearings 421B and 422B are attached to journals 411B and 412B, respectively. Needle bearings 423B and 424B are attached to eccentric portions 413B and 414B, respectively.

  The crank assembly 400C includes a crankshaft 410C and four needle bearings 421C, 422C, 423C, and 424C. The crankshaft 410C includes two journals 411C and 412C and two eccentric portions 413C and 414C. The eccentric portions 413C and 414C are formed between the journals 411C and 412C. The journals 411C and 412C are coaxial, while the eccentric portions 413C and 414C are off-axis. The eccentric portions 413C and 414C are eccentric with respect to the journals 411C and 412C, respectively. The eccentric portions 413C and 414C are thicker than the journals 411C and 412C, respectively. Needle bearings 421C and 422C are attached to journals 411C and 412C, respectively. Needle bearings 423C and 424C are attached to eccentric portions 413C and 414C, respectively.

  The crank assembly 400D includes a crankshaft 410D and four needle bearings 421D, 422D, 423D, and 424D. The crankshaft 410D includes two journals 411D and 412D and two eccentric portions 413D and 414D. The eccentric portions 413D and 414D are formed between the journals 411D and 412D. The journals 411D and 412D are coaxial, while the eccentric portions 413D and 414D are off-axis. The eccentric portions 413D and 414D are eccentric with respect to the journals 411D and 412D, respectively. The eccentric portions 413D and 414D are thicker than the journals 411D and 412D, respectively. Needle bearings 421D and 422D are attached to journals 411D and 412D, respectively. Needle bearings 423D and 424D are attached to the eccentric portions 413D and 414D, respectively.

  The designer may make the diameters of the eccentric portions 413B and 414B of the crankshaft 410B coincide with the diameters of the journals 411C and 412C of the crankshaft 410C. In this case, needle bearings with common model numbers are selected as bearings attached to the eccentric portions 413B and 414B and the journals 411C and 412C.

  The designer may make the diameters of the eccentric portions 413C and 414C of the crankshaft 410C coincide with the diameters of the journals 411D and 412D of the crankshaft 410D. In this case, needle bearings with common model numbers are selected as bearings attached to the eccentric portions 413C and 414C and the journals 411D and 412D.

<Fourth embodiment>
The designer can design the speed reducer based on various methods. In the fourth embodiment, an exemplary design procedure is described.

  FIG. 5 is a conceptual diagram illustrating an exemplary design procedure of the speed reducer. With reference to FIG. 5, an exemplary design procedure for a reducer is described.

  FIG. 5 shows three blocks. Each of the three blocks indicates a design object of the reduction gear. The design shown in each of the three blocks may be done in parallel. Alternatively, the design shown in each of the three blocks may be performed sequentially. The principle of this embodiment is not limited to a specific execution order of the three blocks.

  A designer designs a housing cylinder (an outer cylinder part or a carrier part), a gear part, and a crank assembly. The housing cylinder and the gear portion may be designed based on conditions relating to the reduction ratio, torque, and size required for the reduction gear.

  The crank assembly may be designed with reference to design data of another reduction gear that has already been designed. The dimension value of the eccentric part shown in the design data of the other speed reducer is assigned to the diameter of the journal. The designer can select a bearing having the same model number as the bearing used for the other speed reducer for the bearing attached to the journal. Therefore, the design principle described in connection with the above-described embodiment can reduce not only the logistics work related to the management of the bearing but also the work of the design work for designing a new speed reducer.

  The principles of the various embodiments described above may be combined to meet the requirements for a reducer.

  The principle of the above-described embodiment is suitably used for various speed reducer designs.

100, 100A ... Reducer 210, 210A ... Outer cylinder Part 220, 220A ... Carrier part 310, 310A ... Gear 320, 320A ... Gears 400, 400A, 400B, 400C, 400D ... Crank assemblies 410, 410A ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Crankshaft 411,411A, 411B, 411C, 411D ・ ・ ・ Journal 412 and 412A ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・.... Journals 413, 413A, 413B, 413C, 413D ... Eccentric parts 414, 414A, 414B 414C, 414D Eccentric part 421, 421A ... Bearings 421B, 421C, 421D ... ... Needle bearings 422, 422A ......... Bearings 422B, 422C, 422D ... Needle bearings 423, 423A ......... Bearings 423B, 423C, 423D ... Needle bearings 424, 424A・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Bearings 424B, 424C, 424D ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Needle bearings FMX, SMX ・ ・ ・ ・ ・ ・············ Main spindle FTX, STX ... Axis

Claims (5)

The first output unit is rotated about the first main axis by performing a rotational movement around the first transmission shaft that is separated from the first main axis defined as the rotation center axis of the first output unit by a first distance. A first speed reducer having a first crank assembly for swinging the first swing gear;
By performing a rotational movement around a second transmission shaft that is separated from the second main shaft defined as the rotation center axis of the second output portion by a second distance that is different from the first distance, the second main shaft rotates about the second main shaft. A second reduction gear having a second crank assembly for swinging the second swing gear so as to rotate the two output portions;
The first crank assembly includes a first crankshaft including a first journal and a first eccentric portion eccentric with respect to the first journal; a first shaft support bearing attached to the first journal; A first gear support bearing disposed between one eccentric portion and the first swing gear,
The second crank assembly includes a second crankshaft including a second journal and a second eccentric portion eccentric with respect to the second journal, a second shaft support bearing attached to the second journal, and the second crankshaft. A second gear support bearing disposed between the two eccentric portions and the second swing gear,
The first gear support bearing is a reduction gear group that conforms in shape to the second shaft support bearing. The reduction gear group according to claim 1, wherein each of the first shaft support bearing, the first gear support bearing, the second shaft support bearing, and the second gear support bearing is a needle bearing. The first shaft support bearing is different in shape from the first gear support bearing,
The reduction gear group according to claim 2, wherein the second shaft support bearing is different in shape from the second gear support bearing. The distance relationship between the rotation center axis of the output unit and the transmission rotation axis of the crank assembly that transmits the driving force for rotating the output unit around the rotation center axis is different from that of the other reduction device. A reduction gear,
A first output section that rotates around a first main axis defined as the rotation center axis;
A first oscillating gear that oscillates to cause rotation of the first output portion around the first main axis;
A first crank assembly that performs a rotational motion about a first transmission shaft defined as the transmission rotation shaft that is spaced apart from the first main shaft by a first distance;
The other another speed reducer rotates around a second transmission shaft defined as the transmission rotation shaft separated from the second main shaft defined as the rotation center axis by a second distance different from the first distance. Having a second crank assembly that oscillates the second oscillating gear so as to rotate the second output portion around the second main shaft by performing a movement;
The first crank assembly includes a first crankshaft including a first journal and a first eccentric portion eccentric with respect to the first journal; a first shaft support bearing attached to the first journal; A first gear support bearing disposed between one eccentric portion and the first swing gear,
The second crank assembly includes a second crankshaft including a second journal and a second eccentric portion eccentric with respect to the second journal, a second shaft support bearing attached to the second journal, and the second crankshaft. A second gear support bearing disposed between the two eccentric portions and the second swing gear,
The first gear support bearing is a reduction gear that conforms in shape to the second shaft support bearing. The distance relationship between the rotation center axis of the output unit and the transmission rotation axis of the crank assembly that transmits the driving force for rotating the output unit around the rotation center axis is different from that of the other reduction device. A reduction gear design method,
Designing a first output portion that rotates about a first main axis defined as the rotation center axis;
Designing a first oscillating gear that oscillates to cause rotation of the first output portion about the first main axis;
Designing a first crank assembly that performs a rotational motion about a first transmission shaft defined as the transmission rotation shaft spaced from the first main shaft by a first distance;
The other another speed reducer rotates around a second transmission shaft defined as the transmission rotation shaft separated from the second main shaft defined as the rotation center axis by a second distance different from the first distance. Having a second crank assembly that oscillates the second oscillating gear so as to rotate the second output portion around the second main shaft by performing a movement;
The second crank assembly includes a second crankshaft including a second journal and a second eccentric portion eccentric with respect to the second journal, a second shaft support bearing attached to the second journal, and the second crankshaft. A second gear support bearing disposed between the two eccentric portions and the second swing gear,
Designing the first crank assembly comprises:
(I) designing a first crankshaft including a first journal and a first eccentric portion eccentric to the first journal;
(Ii) determining to use a bearing that conforms to the second shaft support bearing as a first gear support bearing disposed between the first eccentric portion and the first swing gear. And a reduction gear design method.