JP6721389B2 - Gear device - Google Patents

Description

The present invention relates to a gear device having a mechanism for converting a rotational movement of a gear into a linear movement.

Various gear devices have been developed in various technical fields such as industrial robots, machine tools, and vehicles (see Patent Document 1). Patent Document 1 discloses a gear device having a mechanism for converting rotational movement of a gear into linear movement.

JP, 2005-337412, A

The small size of the gearing in the direction of extension of the rotary shaft is preferred in many technical fields. However, the structure of the gear device of Patent Document 1 has to have a large dimension in the extending direction of the output shaft.

An object of the present invention is to provide a gear device having a small dimension in the extending direction of a rotary shaft.

A gear device according to an aspect of the present invention, a gear, an outer cylinder having an inner peripheral portion in which the inner teeth for meshing the gear are formed, and the center of the gear is rotated around a predetermined rotation axis, A drive mechanism including a crankshaft assembly that gives swinging rotation to the gear, a carrier that rotates around the rotation axis according to swinging rotation of the gear, and a motion that converts the rotary motion of the carrier into a linear motion. And a conversion unit. The crankshaft assembly is arranged in an internal space formed by the outer cylinder and the carrier in which the gear is housed. The motion converting portion is disposed in the internal space, is connected to the tubular body in the internal space so as to receive rotation of the tubular body integrally formed with the carrier, and the tubular body , in response to rotation of the tubular body, including a linear movement portion that moves straight line manner along the extending direction of the rotary shaft.

According to the above configuration, the linear motion section that moves linearly in response to the rotation of the rotating section is connected to the rotating section in the internal space in which the gear is accommodated, so that the internal space needs only to accommodate the gear. Instead, it is also used for accommodating a connecting portion between the rotating portion and the linearly moving portion that linearly moves along the extending direction of the rotating shaft of the rotating portion. Therefore, the designer can give the gear device a small dimension in the extending direction of the rotating shaft.
With regard to the above configuration, the carrier is separated from the first end plate integrally formed with the tubular body in the extending direction of the rotary shaft from the first end plate, and the carrier is attached to the first end plate. And a second end plate to be connected. One end of the tubular body may be inserted into a through hole formed in the second end plate.

With regard to the above configuration, the linear motion section is a rod member extending along the rotation axis.

According to the above configuration, the direct acting part is the rod member extending along the rotation axis of the rotating part, so that the designer can arrange the direct acting part near the rotating part. Since the gear device does not require a large space for accommodating the connecting structure for connecting the linear motion portion to the rotating portion, the designer can give the gear device a small dimension in the radial direction.

With regard to the above configuration, the rod member may be a ball screw. The tubular body may be each other chewing with the ball screw.

According to the above configuration, since the rod member is the ball screw, the gear device can convert the rotational movement of the gear into the linear movement of the ball screw with a small friction loss.

With regard to the above-mentioned configuration, the outer shell has an outer cylinder having an inner peripheral portion formed with inner teeth that mesh with the gear, a first end plate surrounded by the outer cylinder, and the first end plate to the rotary shaft. And a second end plate that is separated in the extending direction of and is surrounded by the outer cylinder. The inner space may be surrounded by the outer cylinder, the first end plate, and the second end plate. The tubular body may be arranged so as not to project from the first end plate and the second end plate.

According to the above configuration, the inner space is surrounded by the outer cylinder, the first end plate, and the second end plate, so that the gear, the drive mechanism, and the motion conversion unit are protected by the outer shell. Since the tubular body is arranged so as not to project from the first end plate and the second end plate, the designer can give the gear device a small dimension in the extending direction of the rotating shaft.

With regard to the above configuration, the drive mechanism may include a crankshaft assembly that imparts oscillating rotation to the gear such that the center of the gear revolves around the rotation axis. The crankshaft assembly may be connected to the first end plate and the second end plate to rotate the first end plate and the second end plate about the rotation axis. The tubular body may rotate around the rotation axis integrally with the first end plate and the second end plate.

According to the above configuration, the crankshaft assembly is connected to the first end plate and the second end plate, so that the center of the gear that meshes with the inner teeth of the outer cylinder circulates around the rotation shaft. While the assembly imparts a swinging rotation to the gear, the swinging rotary motion of the gear can be converted into a rotary motion of the first end plate and the second end plate around the rotation axis. The cylindrical body that rotates integrally with the first end plate and the second end plate meshes with the ball screw, so that the ball screw can move linearly during the rotation of the cylindrical body.

With regard to the above configuration, the crankshaft assembly includes a crankshaft having a journal rotating about a transmission shaft extending parallel to the rotation shaft at a position distant from the rotation shaft, and an eccentric portion eccentric from the transmission shaft. May be included. The gear may be attached to the eccentric part.

According to the above configuration, since the gear is attached to the eccentric portion that is eccentric from the transmission shaft, the gear can oscillate around the rotation shaft according to the rotation of the crankshaft around the transmission shaft. The transmission shaft extends parallel to the rotation shaft at a position away from the rotation shaft, so that the designer can place the crankshaft assembly at a position away from the ball screw and the tubular body. Therefore, the gear device can have a simple structure around the motion converting portion.

With regard to the above configuration, the gear may be a trochoidal gear.

According to the above configuration, since the gear is the trochoid gear, the backlash between the outer cylinder and the trochoid gear is very small. Therefore, the gear device may be incorporated in mechanical equipment that requires high accuracy.

The gear device described above may have a small dimension in the extending direction of the rotating shaft.

It is a conceptual diagram of the gear device of 1st Embodiment. It is a conceptual diagram of the gear device of 2nd Embodiment. It is a conceptual diagram of the gear device of 3rd Embodiment. It is a schematic sectional drawing which follows the AA line shown in FIG.

<First Embodiment>
Regarding the conventional gear device, the cylindrical body with which the ball screw meshes is arranged outside the space in which the gear is housed (see Patent Document 1). Therefore, a component for holding the ball screw and the tubular body (for example, a bearing into which the tubular body is inserted or a housing holding the bearing) is also arranged outside the space in which the gear is accommodated. As a result, conventional gear systems have many components located outside the space in which the gears are housed, and have long housing dimensions in the direction of extension of the gear system's axis of rotation (ie, the ball screw axis of rotation). Will have. The present inventors have developed a gear device having a housing size that is short in the extending direction of the rotary shaft. In the first embodiment, the concept of the gear device is explained.

FIG. 1 is a conceptual diagram of a gear device 100 according to the first embodiment. The gear device 100 will be described with reference to FIG. 1.

The gear device 100 includes a housing 200, a drive mechanism 300, a gear 400, and a motion conversion unit 500. The housing 200 forms an internal space 201. The drive mechanism 300, the gear 400, and the motion conversion unit 500 are at least partially housed in the internal space 201. In the present embodiment, the outer shell is exemplified by the housing 200.

The drive mechanism 300 may be partially exposed from the housing 200. In this case, the drive mechanism 300 may be connected to a drive source (for example, a motor: not shown) arranged outside the housing 200. If the drive source is built in the housing 200, the drive mechanism 300 may be entirely housed in the housing 200.

The drive mechanism 300 is connected to the drive source and the gear 400. The drive mechanism 300 may be a shaft member that receives a rotational force from a drive source. When the rotational force is transmitted from the drive source to the shaft member, the shaft member rotates. As a result, the gear 400 connected to the shaft member also rotates. The drive mechanism 300 and the gear 400 may form an oscillating gear mechanism (cycloid gear mechanism) or may form a planetary gear mechanism. Alternatively, drive mechanism 300 and gear 400 may form other gear structures. The principle of this embodiment is not limited to a particular structure formed by the drive mechanism 300 and the gear 400.

The rotary motion of the gear 400 is transmitted to the motion conversion unit 500. The motion conversion unit 500 converts the rotational motion of the gear 400 into a linear motion.

The motion converting section 500 includes a rotating section 510 and a linear moving section 520. The rotating part 510 is arranged in the internal space 201. The rotational movement of the gear 400 is transmitted to the rotating unit 510. As a result, the rotating unit 510 rotates about the rotation axis RAX.

Unlike the rotating part 510, a part of the linear motion part 520 projects from the housing 200. The linear motion part 520 is connected to the rotating part 510 in the internal space 201. When the rotating unit 510 rotates about the rotation axis RAX, the linear moving unit 520 moves linearly.

The motion conversion section 500 may have a ball screw. Alternatively, the motion conversion unit 500 may include a rack and a pinion. Still alternatively, the motion conversion unit 500 may be another structure designed to convert rotation about the rotation axis RAX into linear motion of the linear motion unit 520. The principle of the present embodiment is not limited to the specific structure of the motion conversion unit 500.

As shown in FIG. 1, the rotating unit 510 may rotate bidirectionally. In this case, the linear motion section 520 can make a linear reciprocating motion. Alternatively, the rotating unit 510 may rotate in one direction. In this case, the linear movement unit 520 can move linearly in one direction.

The gear device 100 may have a connecting structure (for example, a gear train) that connects the rotating unit 510 and the linear motion unit 520. Alternatively, the rotating part 510 and/or the linear motion part 520 itself may have a structure (for example, a screw structure) that connects them. The principle of the present embodiment is not limited to a specific connection structure between the rotating part 510 and the linear motion part 520.

<Second Embodiment>
The linear motion portion of the gear device described in connection with the first embodiment is arranged at a position apart from the rotation axis of the rotation portion. Alternatively, the linear motion section may be a rod member extending along the rotation axis of the rotary section. In this case, a designer who designs the gear device can form a connecting structure for connecting the linear motion section to the rotary section on the linear motion section and/or the rotary section itself. As a result, the designer can give the motion converter a small size. In the second embodiment, an exemplary gearing having a rod member extending along the axis of rotation of the rotating part is described.

FIG. 2 is a conceptual diagram of the gear device 100A of the second embodiment. The gear device 100A is described with reference to FIGS. 1 and 2. The description of the first embodiment is applied to the elements denoted by the same reference numerals as the first embodiment.

Similar to the first embodiment, the gear device 100A includes a housing 200, a drive mechanism 300, and a gear 400. The description of the first embodiment is incorporated into these elements.

The gear device 100A further includes a motion conversion unit 500A. The motion converting portion 500A includes a rotating portion 510A and a rod member 520A. The rotating unit 510A is arranged in the internal space 201. The rotational movement of the gear 400 is transmitted to the rotating unit 510A. As a result, the rotating unit 510A rotates about the rotation axis RAX.

The rod member 520A extends along the rotation axis RAX, and a part of the rod member 520A projects from the housing 200. The rod member 520A is connected to the rotating portion 510A in the internal space 201. When the rotating unit 510A rotates about the rotation axis RAX, the rod member 520A moves linearly. The rod member 520A corresponds to the linear motion section 520 described with reference to FIG. Therefore, the description regarding the linear motion section 520 may be incorporated into the rod member 520A.

The rod member 520A may be a ball screw. In this case, the rotating portion 510A may be a tubular body having an inner peripheral surface formed with a female screw that meshes with the ball screw. Alternatively, the rotating portion 510A may be another component formed so as to surround the outer peripheral surface of the rod member 520A.

The rod member 520A is provided with another structure, instead of the ball screw, which is formed so as to be connected to the rotating portion 510A and which is capable of converting the rotational movement of the rotating portion 510A around the rotation axis RAX into a linear movement. You may be asked. Therefore, the principle of the present embodiment is not limited to the specific structure of the motion conversion unit 500A.

<Third Embodiment>
Designers can design various gear devices based on the design principles described in connection with the above embodiments. In the third embodiment, an exemplary gear device is described.

FIG. 3 is a conceptual diagram of the gear device 100B of the third embodiment. FIG. 4 is a schematic sectional view taken along the line AA shown in FIG. The gear device 100B will be described with reference to FIGS. 2 to 4.

The gear device 100B includes an outer cylinder 210, a carrier 220, three crankshaft assemblies 300B (FIG. 3 shows one of the three crankshaft assemblies 300B), a gear unit 400B, and a motion conversion unit. 500B and two main bearings 610 and 620 are provided. The outer cylinder 210 and the carrier 220 form the housing 200 described with reference to FIG. The description of the housing 200 may be incorporated into the outer cylinder 210 and the carrier 220. The crankshaft assembly 300B corresponds to the drive mechanism 300 described with reference to FIG. The description regarding the drive mechanism 300 may be incorporated into the crankshaft assembly 300B. The gear unit 400B corresponds to the gear 400 described with reference to FIG. The description regarding the gear 400 may be incorporated into the gear unit 400B.

The driving force generated by a motor (not shown) or another driving source (not shown) is input to each of the three crankshaft assemblies 300B. The driving force input to each of the three crankshaft assemblies 300B is transmitted to the gear portion 400B arranged in the internal space 201B surrounded by the outer cylinder 210 and the carrier 220.

As shown in FIG. 3, the two main bearings 610 and 620 are fitted in the annular space formed between the outer cylinder 210 and the carrier 220 surrounded by the outer cylinder 210. Each of the two main bearings 610 and 620 enables rotational movement of the carrier 220 within the outer cylinder 210. The common central axis of the two main bearings 610 and 620 corresponds to the rotation axis RAX described with reference to FIG. The carrier 220 is rotated around the rotation axis RAX in the outer cylinder 210 by the driving force transmitted to the gear portion 400B.

As shown in FIG. 3, the outer cylinder 210 includes a substantially cylindrical case 211 and a plurality of inner tooth pins 212. The case 211 cooperates with the carrier 220 to define a cylindrical internal space 201B in which the crankshaft assembly 300B, the gear portion 400B, and the motion conversion portion 500B are housed. The plurality of inner tooth pins 212 are arranged in an annular shape along the inner peripheral surface of the case 211 to form an inner tooth ring.

Each of the plurality of internal tooth pins 212 is a substantially columnar member extending in the extending direction of the rotation axis RAX. Each of the plurality of inner tooth pins 212 is fitted into a groove formed on the inner wall of the case 211. Therefore, each of the plurality of inner tooth pins 212 is properly held by the case 211.

As shown in FIG. 3, the plurality of internal tooth pins 212 are annularly arranged around the rotation axis RAX at substantially constant intervals. The half circumferential surface of each of the plurality of inner tooth pins 212 projects from the inner wall of the case 211 toward the rotation axis RAX. Therefore, the plurality of inner tooth pins 212 function as a plurality of inner teeth that mesh with the gear portion 400B. In the present embodiment, the inner teeth are exemplified by each of the plurality of inner tooth pins 212.

As shown in FIG. 3, the carrier 220 includes a base 230 and an end plate 240. The carrier 220 is generally cylindrical. The end plate 240 has a substantially disc shape. The peripheral surface of the end plate 240 is partially surrounded by the outer cylinder 210. The carrier 220 can rotate in the outer cylinder 210 around the rotation axis RAX.

The base portion 230 includes a substantially disk-shaped substrate portion 231 (see FIG. 3) and three shaft portions 232 (see FIG. 4). The peripheral surface of the substrate portion 231 is partially surrounded by the outer cylinder 210. The board portion 231 is separated from the end plate 240 in the extending direction of the rotation axis RAX. The board portion 231 is substantially coaxial with the end plate 240. That is, the rotation axis RAX corresponds to the central axes of the substrate portion 231 and the end plate 240. The internal space 201B is surrounded by the substrate portion 231, the end plate 240, and the case 211. In the present embodiment, the first end plate is exemplified by one of the substrate portion 231 and the end plate 240. The second end plate is exemplified by the other of the substrate portion 231 and the end plate 240.

The substrate portion 231 includes an inner surface 233 and an outer surface 234 opposite to the inner surface 233. The inner surface 233 faces the gear portion 400B. The inner surface 233 and the outer surface 234 are along a virtual plane (not shown) orthogonal to the rotation axis RAX.

The central through hole 235 (see FIG. 3) and the three holding through holes 236 (FIG. 3 shows one of the three holding through holes 236) are formed in the substrate portion 231. The center through hole 235 extends between the inner surface 233 and the outer surface 234 along the rotation axis RAX. The rotation axis RAX corresponds to the central axis of the central through hole 235. The centers of the three holding through holes 236 are arranged at substantially equal intervals on a virtual circle (not shown) centered on the rotation axis RAX.

FIG. 3 shows the transmission axis TAX in addition to the rotation axis RAX. The transmission axis TAX is defined at a position apart from the rotation axis RAX. The transmission axis TAX is substantially parallel to the rotation axis RAX. The holding through hole 236 extends between the inner surface 233 and the outer surface 234 along the transmission axis TAX. The transmission shaft TAX corresponds to the rotation center axis of the crankshaft assembly 300B and the center axis of the holding through hole 236. A part of the crankshaft assembly 300B is arranged in the holding through hole 236.

The end plate 240 includes an inner surface 243 and an outer surface 244 opposite to the inner surface 243. The inner surface 243 faces the gear portion 400B. The inner surface 243 and the outer surface 244 are along an imaginary plane (not shown) orthogonal to the rotation axis RAX.

A central through hole 245 (see FIG. 3) and three holding through holes 246 (FIG. 3 shows one of the three holding through holes 246) are formed in the end plate 240. The central through hole 245 extends between the inner surface 243 and the outer surface 244 along the rotation axis RAX. The rotation axis RAX corresponds to the central axis of the central through hole 245. The centers of the three holding through holes 246 are arranged at substantially equal intervals on a virtual circle (not shown) centering on the rotation axis RAX. Each of the three holding through holes 246 extends between the inner surface 243 and the outer surface 244 along the transmission axis TAX. The transmission axis TAX corresponds to the central axis of the holding through hole 246. A part of the crankshaft assembly 300B is arranged in the holding through hole 246. The three holding through holes 246 formed in the end plate 240 are substantially coaxial with the three holding through holes 236 formed in the substrate portion 231.

Each of the three shaft portions 232 extends from the inner surface 233 of the base plate portion 231 toward the inner surface 243 of the end plate 240. The end plate 240 is connected to the tip surface of each of the three shaft portions 232. The end plate 240 may be connected to the tip surface of each of the three shaft portions 232 by reamer bolts, locating pins or other suitable fastening techniques. The principles of this embodiment are not limited to a particular connection technique between the end plate 240 and each of the three shaft portions 232.

As shown in FIG. 3, the gear portion 400B is disposed between the inner surface 233 of the base plate portion 231 and the inner surface 243 of the end plate 240. The three shaft portions 232 penetrate the gear portion 400B and are connected to the end plate 240.

As shown in FIG. 3, the gear unit 400B includes two trochoid gears 410 and 420. The trochoid gear 410 is arranged between the end plate 240 and the trochoid gear 420. The trochoidal gear 420 is arranged between the substrate portion 231 and the trochoidal gear 410. The trochoidal gears 410 and 420 may be formed based on a common design drawing.

Each of the trochoid gears 410 and 420 includes a plurality of external teeth 430 (see FIG. 4) protruding toward the inner wall of the case 211. When the crankshaft assembly 300B rotates around the transmission axis TAX, the trochoid gears 410 and 420 move in a circular manner (that is, swing) in the case 211 while engaging the plurality of outer teeth 430 with the plurality of inner tooth pins 212. Rotate. During this time, the centers of the trochoid gears 410 and 420 revolve around the rotation axis RAX. The rotation of the carrier 220 in the outer cylinder 210 is caused by the swinging rotation of the trochoid gears 410 and 420.

The central through hole 411 is formed at the center of the trochoid gear 410. The central through hole 421 is formed at the center of the trochoid gear 420. The central through hole 411 communicates with the central through hole 245 of the end plate 240 and the central through hole 421 of the trochoid gear 420. The central through hole 421 communicates with the central through hole 235 of the substrate portion 231 and the central through hole 411 of the trochoid gear 410. The central through holes 411, 421 of the trochoid gears 410, 420 may be larger in diameter than the central through holes 235, 245 of the substrate portion 231 and the end plate 240.

As shown in FIG. 4, three circular through holes 422 are formed in the trochoid gear 420. Similarly, three circular through holes are formed in the trochoid gear 410. The circular through hole 422 of the trochoid gear 420 and the circular through hole of the trochoid gear 410 cooperate with the holding through holes 236 and 246 of the base plate 231 and the end plate 240 to form an accommodation space in which the crankshaft assembly 300B is accommodated. Form.

Three trapezoidal through holes 413 (FIG. 3 shows one of the three trapezoidal through holes 413) are formed in the trochoid gear 410. Three trapezoidal through holes 423 (see FIG. 4) are formed in the trochoid gear 420. The shaft portion 232 of the carrier 220 penetrates the trapezoidal through holes 413 and 423. The sizes of the trapezoidal through holes 413 and 423 are determined so as not to interfere with the shaft portion 232.

Each of the three crankshaft assemblies 300B includes an input gear 310, a crankshaft 320, two journal bearings 331 and 332, and two crank bearings 341 and 342. The input gear 310 meshes with a gear portion (not shown) formed on a shaft (not shown) of a motor (not shown). When the motor rotates the shaft, the input gear 310 rotates about the transmission axis TAX.

The crankshaft 320 includes a first journal 321, a second journal 322, a first eccentric portion 323, and a second eccentric portion 324. The first journal 321 is inserted into the holding through hole 246 of the end plate 240. The second journal 322 is inserted into the holding through hole 236 of the board portion 231. The journal bearing 331 is fitted in the annular space between the first journal 321 and the inner wall of the end plate 240 forming the holding through hole 246. As a result, the first journal 321 is connected to the end plate 240. The journal bearing 332 is fitted in the annular space between the second journal 322 and the inner wall of the base plate portion 231 forming the holding through hole 236. As a result, the second journal 322 is connected to the board portion 231.

The first eccentric portion 323 is located between the first journal 321 and the second eccentric portion 324. The second eccentric portion 324 is located between the second journal 322 and the first eccentric portion 323. The crank bearing 341 is fitted in the annular space between the first eccentric portion 323 and the inner wall of the trochoid gear 410 forming the circular through hole. As a result, the trochoid gear 410 is attached to the first eccentric portion 323. The crank bearing 342 is fitted in the annular space between the second eccentric portion 324 and the inner wall of the trochoid gear 420 that forms the circular through hole 422. As a result, the trochoid gear 420 is attached to the second eccentric portion 324. In the present embodiment, the gear is exemplified by one of the trochoid gears 410 and 420.

The first journal 321 is substantially coaxial with the second journal 322 and rotates about the transmission axis TAX. Each of the first eccentric portion 323 and the second eccentric portion 324 is formed in a cylindrical shape and is eccentric from the transmission shaft TAX. Each of the first eccentric portion 323 and the second eccentric portion 324 eccentrically rotates with respect to the transmission shaft TAX, and imparts oscillating rotation to the trochoid gears 410 and 420. Since the trochoid gears 410 and 420 mesh with the inner toothed ring of the fixed outer cylinder 210, the swinging rotation of the trochoid gears 410 and 420 is converted into the orbital motion of the crankshaft 320 around the rotation axis RAX. Since the end plate 240 and the base plate portion 231 are connected to the first journal 321 and the second journal 322, respectively, the revolving motion of the crankshaft 320 is the rotational motion of the end plate 240 and the base plate part 231 around the rotation axis RAX. To be converted. The orbital phase difference between the trochoid gears 410 and 420 is determined by the difference in the eccentric direction between the first eccentric portion 323 and the second eccentric portion 324. In the present embodiment, the journal is exemplified by the first journal 321 or the second journal 322. The eccentric portion is exemplified by the first eccentric portion 323 or the second eccentric portion 324.

The motion converting section 500B includes a female screw cylinder 510B and a ball screw 520B. The female screw cylinder 510B has a generally cylindrical shape. The central axis of the female screw cylinder 510B substantially coincides with the rotation axis RAX. A female screw is formed on the inner peripheral surface of the female screw cylinder 510B. In the present embodiment, the female screw cylinder 510B is formed integrally with the board portion 231. Therefore, the female screw cylinder 510B can rotate integrally with the carrier 220 around the rotation axis RAX.

The female screw cylinder 510B extends from the inner surface 233 of the substrate portion 231 toward the end plate 240. The front end portion of the female screw cylinder 510B is inserted into the central through hole 245 of the end plate 240. The front end surface of the female screw cylinder 510B is substantially flush with the outer surface 244 of the end plate 240. The female screw cylinder 510B corresponds to the rotating portion 510A described with reference to FIG. The description of the rotating portion 510A may be incorporated into the female screw cylinder 510B.

In the present embodiment, the cylindrical body is exemplified by the female screw cylinder 510B. As described above, the female screw cylinder 510B is formed integrally with the board portion 231. Alternatively, the tubular body may be an internally threaded tube integrally formed with the end plate 240. Further alternatively, the cylindrical body may be a female screw cylinder formed separately from the base plate portion 231 and the end plate 240. In this case, the female screw cylinder is arranged between the base plate 231 and the end plate 240, and is connected to at least one of the base plate 231 and the end plate 240 by an appropriate fixing tool such as a screw or a pin.

The ball screw 520B includes a screw rod 521 and a plurality of balls 522. The screw rod 521 extends along the rotation axis RAX. A spiral groove is formed on the outer peripheral surface of the screw rod 521. Each of the plurality of balls 522 is fitted into the space between the female screw groove formed in the female screw cylinder 510B and the spiral groove. As a result, when the female screw cylinder 510B rotates integrally with the carrier 220, the screw rod 521 can linearly move along the extending direction of the rotation axis RAX with a small friction loss. The ball screw 520B corresponds to the rod member 520A described with reference to FIG. The description regarding the rod member 520A may be incorporated into the ball screw 520B.

The design principles described in connection with the various embodiments above are applicable to various gear devices. Some of the various features described in connection with one of the various embodiments described above may be applied to the gear arrangement described in connection with another of the other embodiments. The design principle described above can also be applied to a center crank type gear device.

The principles of the above-described embodiments are preferably applied to various gear devices.

100, 100A, 100B... Gear device 200... 201, 201B... Internal space 210...・External cylinder 231...・・・・・・・・・End plate 300 ・・・・・・・Drive mechanism 300B ・・・・Crankshaft assembly 320... Crankshaft 321...・・・・・・・First Journal 322 ・・・・・・・・・2 Journal 323...First eccentric part 324...・・・・・・・・Second eccentric part 400 ・・・・・・・・Gear 400B・・・··········Gear portion 410, 420 ····· trochoidal gear 500, 500A, 500B...・・・・・・・・・Motion converters 510, 510A ・・・・Rotator 510B ・・・・・・・・・・・・ Female threaded cylinder 520 ・・・・・・・・・・・Direct-acting part 520A・・・・・・・・・・Rod member 520B・・・・・・・・Ball screw RAX・・・・・・・・・Rotation axis TAX・・・・・・・・....Transmission shaft

Claims (8)

Gears,
An outer cylinder having an inner peripheral portion formed with inner teeth for meshing the gears,
A drive mechanism including a crankshaft assembly that imparts oscillating rotation to the gear such that the center of the gear revolves around a predetermined rotation axis ;
A carrier that rotates around the rotation axis according to the swinging rotation of the gear,
A motion conversion unit that converts the rotary motion of the carrier into a linear motion,
The crankshaft assembly is arranged in an internal space formed by the outer cylinder and the carrier, in which the gear is accommodated,
The motion conversion unit is disposed in the internal space, is connected to the tubular body in the internal space so as to receive rotation of the tubular body integrally formed with the carrier, and the tubular body , in response to rotation of the tubular body, including a linear movement portion that moves straight line manner along the extending direction of said rotary shaft,
Gear device. The carrier is separated from the first end plate integrally formed with the tubular body in the extending direction of the rotating shaft from the first end plate, and is connected to the first end plate. Including two end plates,
One end of the tubular body is inserted into a through hole formed in the second end plate,
The gear device according to claim 1. The linearly moving portion is a rod member extending along the rotation axis.
The gear device according to claim 1 or 2 . The rod member is a ball screw,
Said tubular body, cormorants if chewing with the ball screw,
The gear device according to claim 3 . The inner space is surrounded by the outer cylinder, the first end plate and the second end plate,
The tubular body is arranged so as not to project from the second end plate,
The gear device according to claim 2 . The crankshaft assembly rotates the first end plate and the second end plate around the rotation axis,
The tubular body rotates integrally with the first end plate around the rotation axis,
The gear device according to claim 5 . The crankshaft assembly includes a crankshaft having a journal that rotates about a transmission shaft that extends parallel to the rotation shaft at a position apart from the rotation shaft, and an eccentric portion that is eccentric from the transmission shaft.
The gear is attached to the eccentric part,
The gear device according to any one of claims 1 to 6 . The gear is a trochoidal gear,
The gear device according to any one of claims 1 to 7.

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