JP2009191946A - Eccentric oscillation type gear device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a large reduction ratio in transmitting rotation through a transmission gear even when the transmission gear and external tooth gears rockably rotating while being meshed with an internal tooth pin on the inner surface of an outer cylinder are provided axially adjoining in the outer cylinder. <P>SOLUTION: An eccentric oscillation type gear device comprises the transmission gear 20 provided axially adjoining eccentric parts 10a, 10b of a crankshaft 10 and rotated integrally with the crankshaft 10, and the external tooth gears 14, 16 mounted to the eccentric parts 10a, 10b of the crankshaft 10 and rockably rotating interlocked with the eccentric rotation of the eccentric parts 10a, 10b while being meshed with the internal tooth pin 3 on the inner surface of the outer cylinder 2. The internal tooth pin 3 has mesh parts 3a, 3b meshed with the external tooth gears 14, 16, and a receiving part 3c provided axially adjoining the mesh parts 3a, 3b and recessed to receive the outer peripheral end of the transmission gear 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an eccentric oscillating gear device.

  2. Description of the Related Art Conventionally, an eccentric oscillating gear device is known in which an output rotation decelerated from an input rotation is obtained by oscillating and rotating an external gear while meshing with an internal tooth of an outer cylinder by an eccentric portion of a crankshaft. (For example, refer to Patent Document 1).

  FIG. 7 shows a structure of an eccentric oscillating gear device according to a conventional example disclosed in Patent Document 1. In this conventional eccentric oscillating gear device, a crankshaft 104 having two eccentric portions 104a and 104b arranged in the axial direction in the outer cylinder 102 is provided so as to be rotatable around the axis. External gears 108a and 108b are attached to the eccentric portions 104a and 104b via needle bearings 106a and 106b, respectively. A large number of axial pins 102a extending in the axial direction are provided on the inner surface of the outer cylinder 102 at predetermined intervals over the entire circumference, and the external gears 108a and 108b are engaged with the internal teeth pins 102a. The outer cylinder 102 accommodates a carrier 112 attached to the outer cylinder 102 so as to be relatively rotatable by a pair of bearings 110a and 110b.

When the input rotation is transmitted to the crankshaft 104, the external gears 108a and 108b are oscillated and rotated while meshing with the internal teeth pins 102a on the inner surface of the outer cylinder 102 in conjunction with the eccentric portions 104a and 104b. The carrier 112 is rotated relative to the outer cylinder 102 by transmitting the swinging rotation of the external gears 108a and 108b, and an output rotation is obtained from the carrier 112. Further, the eccentric portion 104a of the crankshaft 104 is arranged so that a transmission gear 118 (intermediate gear) that meshes with a cylindrical gear 116 provided at a radially central portion in the outer cylinder 102 is sandwiched between the external gears 108a and 108b. The rotation of the crankshaft 104 is also transmitted to the cylindrical gear 116 via the transmission gear 118. The cylindrical gear 116 transmits the input rotation to another crankshaft (not shown) disposed around the cylindrical gear 116. As with the crankshaft 104, the other crankshaft includes two eccentric portions for swinging and rotating the external gears 108a and 108b, and a transmission gear meshing with the cylindrical gear 116 between the eccentric portions. Have That is, the transmission gear 118 provided on the crankshaft 104 transmits the input rotation to the transmission gear of another crankshaft via the cylindrical gear 116.
JP-A-9-57678

  However, in the conventional eccentric oscillating gear device, it is difficult to increase the diameter of the transmission gear 118 and another transmission gear (not shown) in order to avoid contact with the internal tooth pin 102a. There is a problem in that it is difficult to obtain a large reduction ratio in the transmission of rotation via the motor.

  That is, in the above-described conventional eccentric oscillating gear device, the transmission gear 118 and another transmission gear (not shown) are sandwiched between the external gears 108a and 108b, and the external gear 108a is disposed around each of the transmission gears. , 108b is provided with an internal tooth pin 102a. Accordingly, when the diameter of each transmission gear is to be increased in order to obtain a large reduction ratio, the size of the diameter is limited in order to avoid contact with the surrounding internal pin 102a.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an external gear that oscillates and rotates while meshing with a transmission gear and an internal pin on the inner surface of the outer cylinder. An eccentric oscillating gear device capable of obtaining a large reduction ratio in transmission of rotation via a transmission gear even when provided adjacent to each other in the axial direction.

  In order to achieve the above object, an eccentric oscillating gear device according to the present invention is provided with an outer cylinder provided with an internal tooth pin extending in the axial direction on the inner surface, and rotatable around the axis in the outer cylinder, A crankshaft having an eccentric portion, a transmission gear provided axially adjacent to the eccentric portion of the crankshaft and rotating integrally with the crankshaft about the same axis as the rotation shaft of the crankshaft, and the crank An external gear that is attached to an eccentric portion of the shaft and meshes with the internal tooth pin and swings and rotates in conjunction with the eccentric rotation of the eccentric portion, and is provided coaxially with the outer cylinder, A carrier that rotates relative to the outer cylinder by transmitting a swinging rotation, and the inner pin is provided with a meshing portion that meshes with the external gear, and adjacent to the meshing portion in the axial direction. Receiving the outer peripheral end of the transmission gear And a receiving portion which is recessed in a direction away from the axis of rotation of the transmission gear to so that.

  In this eccentric oscillating gear device, a receiving portion that is recessed in a direction away from the rotation shaft of the transmission gear is provided so that the outer peripheral end of the transmission gear is received by the internal tooth pin. For this reason, the transmission gear can be provided so that the outer peripheral end enters a recessed space formed by the receiving portion of the internal tooth pin. Therefore, even if the transmission gear and the external gear that oscillates and rotates while meshing with the internal pin on the inner surface of the outer cylinder are provided adjacent to each other in the axial direction, the transmission gear is formed by the receiving portion. It is possible to increase the diameter and increase the number of teeth while avoiding contact with the internal tooth pin in the concave space. As a result, a large reduction ratio can be obtained in the transmission of rotation via this transmission gear.

  In the eccentric oscillating gear device, the inner tooth pin is attached to the inner surface of the outer cylinder so as to be rotatable about an axis, and the meshing portion of the inner tooth pin is formed in a cylindrical shape having a predetermined diameter. On the other hand, it is preferable that the receiving portion of the internal tooth pin is disposed coaxially with the meshing portion and is formed in a columnar shape having a smaller diameter than the meshing portion.

  In this configuration, since the receiving portion of the inner tooth pin is formed in a columnar shape that is coaxial with the meshing portion and smaller in diameter than the meshing portion, even if the inner tooth pin rotates around the axis on the inner surface of the outer cylinder, The amount of dent on the transmission gear side of the receiving portion of the tooth pin can be kept constant. That is, with this configuration, even when the internal tooth pin rotates about the axis on the inner surface of the outer cylinder, contact with the transmission gear can be stably avoided at the receiving portion of the internal tooth pin.

  In the eccentric oscillating gear device, a plurality of the eccentric portions of the crankshaft are provided side by side in the axial direction of the crankshaft, and the external gear is attached to each of the plurality of eccentric portions, The transmission gear is disposed at one position between the external gears, and a plurality of the meshing portions of the internal gear pins are provided side by side in the axial direction so as to mesh with the external gears. And the said receiving part of this internal tooth pin may be provided in the position corresponding to the said transmission gear between these meshing parts.

  In the eccentric oscillating gear device, the transmission gear is externally fitted to the crankshaft so as to be movable in the axial direction, and the transmission gear and the external gear are sandwiched from both sides in the axial direction. It is preferable to provide a pair of regulating members that regulate the axial movement of the two.

  According to this configuration, even if the axial displacement of the crankshaft occurs, the axial movement of the transmission gear and the external gear is restricted between the pair of restricting members. A predetermined position is maintained between the pair of regulating members. For this reason, the axial length of the receiving portion of the internal tooth pin does not need to be increased by estimating the axial movement of the transmission gear, and is set to a minimum length substantially equal to the axial thickness of the transmission gear. can do. When the receiving portion is provided in the internal tooth pin, the axial length of the meshing portion is reduced accordingly, and the contact area between the external gear and the meshing portion is reduced. Since the axial length can be set to the minimum length, it is possible to minimize the reduction in the contact area between the external gear and the meshing portion, and work between the external gear and the meshing portion. An increase in surface pressure can be suppressed. For this reason, it is possible to suppress the progress of wear and the like of the external gear and the meshing portion due to the increase in the surface pressure, and it is possible to suppress the reduction of the life of the external gear and the internal pin.

  As described above, according to the eccentric oscillating gear device of the present invention, the transmission gear and the external gear that oscillates and rotates while meshing with the internal tooth pin on the inner surface of the outer cylinder are adjacent to each other in the axial direction. Even in the case of being provided, a large reduction ratio can be obtained in the transmission of rotation through the transmission gear.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view along the axial direction of an eccentric oscillating gear device according to an embodiment of the present invention, and FIG. 2 is taken along the line II-II of the eccentric oscillating gear device shown in FIG. FIG. 3 is a perspective view of the internal tooth pin 3 used in the eccentric oscillating gear device. First, with reference to FIGS. 1-3, the structure of the eccentric rocking | fluctuation type gear apparatus by one Embodiment of this invention is demonstrated.

  The eccentric oscillating gear device according to the present embodiment (hereinafter simply referred to as a gear device) is applied as a speed reducer to a turning portion of a turning barrel or arm joint of a robot or a turning portion of various machine tools, for example. The first external gear 14 is oscillated and rotated in conjunction with the first eccentric portion 10a of the crankshaft 10, and the second external gear 16 is oscillated and rotated in conjunction with the second eccentric portion 10b of the crankshaft 10. Thus, an output rotation decelerated from the input rotation is obtained. In the following description of the present embodiment, an example in which a gear device is applied to a robot arm joint will be described.

  Specifically, as shown in FIG. 1, the gear device of the present embodiment includes an outer cylinder 2, an internal tooth pin 3, a carrier 4, a carrier bearing 6, an input shaft 8, a crankshaft 10, A first crank bearing 12a, a second crank bearing 12b, a first external gear 14, a second external gear 16, a first roller bearing 18a, a second roller bearing 18b, and a transmission gear 20 are provided. ing.

  The outer cylinder 2 functions as a case constituting the outer surface of the gear device, and is formed in a substantially cylindrical shape. A flange 2a is provided on the outer surface of the outer cylinder 2, and the flange 2a is fastened to one arm (not shown) at the arm joint of the robot. As shown in FIG. 2, a large number of pin grooves 2 b for attaching the internal tooth pins 3 are formed on the inner surface of the outer cylinder 2. Each pin groove 2b extends in the axial direction of the outer cylinder 2, and has a semicircular cross-sectional shape in a cross section orthogonal to the axial direction. These pin grooves 2 b are provided at equal intervals in the circumferential direction on the entire inner surface of the outer cylinder 2.

  The internal tooth pin 3 meshes with the first external gear 14 and the second external gear 16, and is attached to each pin groove 2 b on the inner surface of the outer cylinder 2. As a result, a large number of internal teeth pins 3 are arranged at equal intervals in the circumferential direction on the inner surface of the outer cylinder 2. And each internal tooth pin 3 is provided in the attitude | position extended in an axial direction by being each engage | inserted by each pin groove | channel 2b, and it is provided rotatably about the axis.

  As shown in FIGS. 1 and 3, each internal tooth pin 3 includes a first meshing portion 3 a, a second meshing portion 3 b, and a receiving portion 3 c. In the present embodiment, the internal tooth pin 3 is formed by integrally forming the meshing portions 3a and 3b and the receiving portion 3c by cutting or the like using a rod-shaped metal material.

  The first meshing portion 3a is a portion where the first external gear 14 meshes. The first meshing portion 3a is provided in a predetermined length from one end portion of the internal tooth pin 3, and is formed in a cylindrical shape having a predetermined diameter.

  The second meshing portion 3b is a portion where the second external gear 16 meshes. The second meshing portion 3b is provided on the internal tooth pin 3 side by side with the first meshing portion 3a in the axial direction. Specifically, the second meshing portion 3b is provided with a length equal to that of the first meshing portion 3a from the other end of the internal tooth pin 3. The second meshing portion 3b is formed in a columnar shape that is coaxial with the first meshing portion 3a and has the same diameter.

  The receiving portion 3 c is a portion for avoiding contact with the transmission gear 20. The receiving portion 3c is provided between the meshing portions 3a and 3b in the internal tooth pin 3 so as to be adjacent to the meshing portions 3a and 3b in the axial direction, and is disposed at a position corresponding to the transmission gear 20. It is installed. And this receiving part 3c is dented in the direction away from the rotating shaft of the transmission gear 20 so that the outer peripheral end of the transmission gear 20 may be received.

  Specifically, the receiving portion 3c is disposed coaxially with the meshing portions 3a and 3b at a position corresponding to the transmission gear 20 between the meshing portions 3a and 3b. It is formed in a cylindrical shape having a smaller diameter than 3b. The axial length of the receiving portion 3c is set to a length substantially equal to the axial thickness of the transmission gear 20. With such a configuration, the outer surface of the receiving portion 3c is recessed by one step with respect to the outer surfaces of the both meshing portions 3a and 3b, and a recessed space is formed around the receiving portion 3c. And the outer peripheral end of the transmission gear 20 is received in a portion on the transmission gear 20 side in the recessed space around the receiving portion 3c. In addition, a gap is formed between the outer surface of the receiving portion 3c and the inner surface of the pin groove 2b by the recessed space formed around the receiving portion 3c, and this gap is used as a lubricant reservoir. Thereby, lubrication between the internal tooth pin 3 and the inner surface of the pin groove 2b can be performed satisfactorily.

  Further, when the internal tooth pin 3 is inserted, the carrier 4 can rotate relative to the outer cylinder 2 around the axis as will be described later, so that the transmission gear 20 is transmitted from the recessed space in the receiving portion 3c. After the crankshaft 10 and the transmission gear 20 are rotated relative to the outer cylinder 2 together with the carrier 4 until the outer teeth 20a of the outer cylinder 2 are removed, the inner tooth pin 3 is axially moved with respect to the pin groove 2b of the outer cylinder 2. It is supposed to be inserted.

  As shown in FIG. 1, the carrier 4 is accommodated in the outer cylinder 2 so as to be coaxial with the outer cylinder 2, and rotates relative to the outer cylinder 2 around the same axis. is there. The carrier 4 is fixed to the other arm portion (not shown) at the arm joint of the robot, and the carrier 4 and the outer cylinder 2 rotate relative to each other to form the one of the arm joints of the robot. The arm portion and the other arm portion pivot on each other on the same axis.

  Specifically, the carrier 4 is supported by the carrier bearing 6 so as to be rotatable relative to the outer cylinder 2. A pair of carrier bearings 6 are provided apart in the axial direction. Each carrier bearing 6 has an outer ring member 6 a fixed to the inner surface of the outer cylinder 2 and an inner ring member 6 b provided integrally on the outer periphery of the carrier 4.

  The carrier 4 includes a base portion 4a, an end plate portion 4b, and three shaft portions 4c.

  The base portion 4a is disposed in the outer cylinder 2 in the vicinity of one end portion in the axial direction. A circular through hole 4d is provided in the central portion of the base portion 4a in the radial direction, and three crankshaft mounting holes 4e (hereinafter simply referred to as mounting holes 4e) are provided around the through hole 4d of the base portion 4a. It is provided at equal intervals in the direction. An inner ring member 6b of the one carrier bearing 6 is integrally provided on the outer peripheral portion of the base portion 4a.

  The end plate portion 4b is provided to be separated from the base portion 4a in the axial direction, and is disposed in the vicinity of the other end portion in the axial direction in the outer cylinder 2. In the outer cylinder 2, a closed space surrounded by both end surfaces of the end plate portion 4 b and the base portion 4 a facing each other and the inner surface of the outer cylinder 2 is formed. Further, a through hole 4f having the same diameter as the through hole 4d of the base portion 4a is provided at the radial center of the end plate portion 4b, and three crankshafts are provided around the through hole 4f of the end plate portion 4b. Mounting holes 4g (hereinafter simply referred to as mounting holes 4g) are provided at positions corresponding to the three mounting holes 4e of the base portion 4a. An inner ring member 6b of the other carrier bearing 6 is integrally provided on the outer peripheral portion of the end plate portion 4b.

  The three shaft portions 4c are integrally provided on the base portion 4a, and are formed in a columnar shape extending linearly from the base portion 4a toward the end plate portion 4b. As shown in FIG. 2, the three shaft portions 4c are arranged at equal intervals in the circumferential direction, and each shaft portion 4c is fastened to the end plate portion 4b by bolts 4h. Thereby, the base part 4a, the shaft part 4c, and the end plate part 4b are integrated.

  The input shaft 8 functions as an input portion to which rotation is input by a drive motor (not shown) provided on one arm portion (not shown), and the end of the input shaft 8 passes through a through hole 4f of the end plate portion 4b. The portion is inserted into the closed space in the outer cylinder 2. The input shaft 8 is arranged such that its axis coincides with the axes of the outer cylinder 2 and the carrier 4 and rotates around its axis. An input gear 8 a is provided on the outer peripheral surface of the end portion of the input shaft 8 inserted into the closed space in the outer cylinder 2.

  Three crankshafts 10 are provided, and each crankshaft 10 is attached to the corresponding mounting hole 4e of the base portion 4a and the mounting hole 4g of the end plate portion 4b, thereby causing the crankshaft 10 to move within the outer cylinder 2. The input shaft 8 is arranged at equal intervals around the input shaft 8.

  Specifically, one end of each crankshaft 10 in the axial direction is attached to the corresponding attachment hole 4e of the base 4a via the first crank bearing 12a, while the other end is an end plate portion. 4b is mounted in the corresponding mounting hole 4g via the second crank bearing 12b. That is, each crankshaft 10 is supported by both crank bearings 12a and 12b so as to be rotatable about the axis with respect to the carrier 4.

  The first crank bearing 12a is a tapered roller bearing in which a truncated cone roller 12e is held between the inner surface of the outer ring member 12c and the outer surface of the inner ring member 12d. In the first crank bearing 12a, the outer surface of the outer ring member 12c is in contact with the inner surface of the mounting hole 4e of the base portion 4a. On the other hand, the inner surface of the inner ring member 12 d is in contact with the outer surface of one end of the crankshaft 10. Further, the end surface of the outer ring member 12c located on the outer side in the axial direction of the crankshaft 10 is in contact with the retaining ring 13a fitted in the groove portion 4k of the inner surface of the mounting hole 4e of the base portion 4a. The first crank bearing 12a is prevented from coming off by the retaining ring 13a. Further, a washer 13b is interposed between the end surface of the inner ring member 12d located on the inner side in the axial direction of the crankshaft 10 and the end surface of the first eccentric portion 10a.

  The second crank bearing 12b is a tapered roller bearing similar to the first crank bearing 12a. In the second crank bearing 12b, the outer surface of the outer ring member 12f is in contact with the inner surface of the mounting hole 4g of the end plate portion 4b. On the other hand, the inner surface of the inner ring member 12g is in contact with the outer surface of the other end portion of the crankshaft 10. An end surface of the outer ring member 12f located on the outer side in the axial direction of the crankshaft 10 is in contact with a retaining ring 13c fitted in a groove portion 4m on the inner surface of the mounting hole 4g of the end plate portion 4b. The second crank bearing 12b is prevented from coming off by the retaining ring 13c. Further, a washer 13d is interposed between the end surface of the inner ring member 12g located on the inner side in the axial direction of the crankshaft 10 and the end surface of the second eccentric portion 10b.

  The crankshaft 10 is provided with a first eccentric portion 10a and a second eccentric portion 10b so as to be arranged at predetermined intervals in the axial direction between both end portions supported by the crank bearings 12a and 12b. The first eccentric portion 10a and the second eccentric portion 10b are each formed in a cylindrical shape eccentric from the axis of the crankshaft 10 by a predetermined amount of eccentricity, and have a predetermined angle phase difference therebetween. Has been placed.

  Further, a fitted portion 10c to which the transmission gear 20 is fitted is provided at a portion of the crankshaft 10 located between the first eccentric portion 10a and the second eccentric portion 10b. A spline groove extending in the axial direction is formed on the outer surface of the fitted portion 10c.

  The first external gear 14 is disposed in the closed space in the outer cylinder 2 and is attached to the first eccentric portion 10a of the crankshaft 10 via the first roller bearing 18a. When the 10 rotates, the first eccentric portion 10a rotates in a swinging manner while meshing with the first meshing portion 3a of the inner tooth pin 3 on the inner surface of the outer cylinder 2 in conjunction with the eccentric rotation of the first eccentric portion 10a.

  Specifically, the first external gear 14 is formed to be slightly smaller than the inner diameter of the outer cylinder 2, and includes an external tooth 14a, a central through hole 14b, and three first eccentric portion insertion holes 14c. Three shaft portion insertion holes 14d are provided.

  The external teeth 14 a mesh with the first meshing portion 3 a of the internal tooth pin 3, and are provided in a number slightly smaller than the number of internal tooth pins 3.

  The central through hole 14b is provided in the central portion in the radial direction of the first external gear 14.

  The three first eccentric portion insertion holes 14c are provided at equal intervals in the circumferential direction around the central portion through hole 14b in the first external gear 14. The first eccentric portion 10a of each crankshaft 10 is inserted into each first eccentric portion insertion hole 14c in a state where the first roller bearing 18a is interposed. The first external gear 14 can be moved relative to the first eccentric portion 10a of the crankshaft 10 in the axial direction.

  The three shaft portion insertion holes 14d are provided at equal intervals in the circumferential direction around the central portion through hole 14b in the first external gear 14, and each of the shaft portion insertion holes 14d has the three first first gears 14d. It is arrange | positioned in the position between the eccentric part insertion holes 14c, respectively. Each shaft portion insertion hole 14d is formed in a circular shape, and each shaft portion 4c of the carrier 4 is inserted into each shaft portion insertion hole 14d with play.

  The second external gear 16 is disposed in the closed space in the outer cylinder 2 and is attached to the second eccentric portion 10b of the crankshaft 10 via the second roller bearing 18b. That is, the first external gear 14 and the second external gear 16 are provided side by side in the axial direction corresponding to the first eccentric portion 10 a and the second eccentric portion 10 b of the crankshaft 10. The second external gear 16 oscillates while meshing with the second meshing portion 3b of the internal pin 3 on the inner surface of the outer cylinder 2 in conjunction with the eccentric rotation of the second eccentric portion 10b when the crankshaft 10 rotates. It is designed to rotate dynamically. The second external gear 16 has the same structure as the first external gear 14.

  Specifically, the second external gear 16 includes an external tooth 14a of the first external gear 14, a central through hole 14b, three first eccentric part insertion holes 14c, and three shaft part insertion holes 14d. Similar external teeth 16a, a central through hole 16b, three second eccentric portion insertion holes 16c, and three shaft portion insertion holes 16d are provided. However, the external teeth 16a mesh with the second meshing portion 3b of the internal tooth pin 3, and the input shaft 8 is inserted into the central through hole 16b with play. Further, the second eccentric portion 10b of the crankshaft 10 is inserted in each second eccentric portion insertion hole 16c with the second roller bearing 18b interposed therebetween, and the second external gear 16 is It can move relative to the eccentric portion 10b in the axial direction.

  The transmission gear 20 transmits the rotation of the input gear 8 a to each crankshaft 10, and three transmission gears 20 are provided corresponding to each crankshaft 10. These three transmission gears 20 are disposed between the first external gear 14 and the second external gear 16 in the closed space in the outer cylinder 2. That is, the first external gear 14, the transmission gear 20, and the second external gear 16 are arranged in this order in the closed space in the axial direction. Each transmission gear 20 is configured to rotate while sliding in contact with the axial end surface of the first external gear 14 or the axial end surface of the second external gear 16 at each end surface in the axial direction. .

  Each transmission gear 20 has an external tooth 20a that meshes with the input gear 8a and a fitting portion 20b that fits into the fitted portion 10c of the crankshaft 10.

  Each transmission gear 20 is provided so as to enter the recessed space formed by the receiving portion 3 c of the internal tooth pin 3 at the outer peripheral end thereof, that is, at a position where the external teeth 20 a are close to the inner surface of the external cylinder 2. That is, each transmission gear 20 rotates while its outer teeth 20a pass through the recessed space formed by the receiving portion 3c. With this configuration, each transmission gear 20 has a maximum diameter in which the adjacent external teeth 20a are not in contact with each other and the external teeth 20a are not in contact with the receiving portion 3c in the recessed space of the receiving portion 3c. It is formed to become.

  In the present embodiment, each transmission gear 20 is externally fitted to the fitted portion 10c of the corresponding crankshaft 10 in the fitting portion 20b so as to be movable in the axial direction, and is the same as the rotating shaft of the crankshaft 10. The crankshaft 10 is rotated integrally with the crankshaft.

  Specifically, the fitting portion 20b is formed by forming a spline groove extending in the axial direction on the inner surface of a circular through-hole provided in the radial center portion of the transmission gear 20. The fitting portion 20b is splined to the fitted portion 10c of the crankshaft 10. Thus, the transmission gear 20 is externally fitted to the fitted portion 10c of the crankshaft 10 so as to be movable in the axial direction.

  In the present embodiment, the first external gear 14, the transmission gear 20, and the second external gear 16 are sandwiched between the outer ring members 6 a and 6 a of the pair of carrier bearings 6 and 6 from both sides in the axial direction. The axial movement of these gears 14, 20, 16 is restricted. That is, in this embodiment, the outer ring member 6a of the carrier bearing 6 functions as a regulating member.

  Further, the outer ring members 6 a and 6 a of the pair of carrier bearings 6 and 6 also restrict the axial movement of the internal tooth pin 3. That is, of the outer ring member 6a of the one carrier bearing 6, the end surface located on the inner side in the axial direction of the crankshaft 10 abuts the corresponding axial end surface of the first meshing portion 3a of each internal tooth pin 3, and the other Of the outer ring member 6 a of the carrier bearing 6, the end surface located on the axially inner side of the crankshaft 10 abuts the corresponding axial end surface of the second meshing portion 3 b of each internal tooth pin 3, and the shaft of each internal tooth pin 3. Directional movement is restricted.

  Next, the operation of the gear device according to the present embodiment will be described.

  First, rotation is input to the input shaft 8 of the gear device by driving a drive motor (not shown). Thereby, the input gear 8 a rotates together with the input shaft 8, and the rotation of the input gear 8 a is transmitted to each crankshaft 10 via each transmission gear 20. At this time, each transmission gear 20 rotates while its outer teeth 20a pass through the recessed space formed by the receiving portion 3c of the inner tooth pin 3, and the contact between the outer teeth 20a and the inner tooth pin 3 is made. Avoided.

  Each crankshaft 10 rotates, and the first eccentric portion 10a and the second eccentric portion 10b of the crankshaft 10 rotate eccentrically, thereby interlocking with the eccentric rotation of the first eccentric portion 10a. The gear 14 oscillates and rotates while meshing with the internal tooth pin 3 on the inner surface of the outer cylinder 2, and the second external gear 16 interlocks with the eccentric rotation of the second eccentric portion 10 b and the inner tooth pin on the inner surface of the outer cylinder 2. Oscillating and rotating while meshing with 3. The oscillating rotation of the first external gear 14 and the second external gear 16 is transmitted to the carrier 4 through the shaft portion 4c, and the entire carrier 4 is rotated with respect to the outer cylinder 2 at a speed reduced from the input rotation. Relative rotation.

  As described above, in the present embodiment, the receiving portion 3 c that is recessed in the direction away from the rotation shaft of the transmission gear 20 is provided so that the inner tooth pin 3 receives the outer peripheral end of the transmission gear 20. For this reason, the transmission gear 20 can be provided so that the outer peripheral end enters the recessed space formed by the receiving portion 3 c of the internal tooth pin 3. Therefore, even if the transmission gear 20, the first external gear 14, and the second external gear 16 are provided adjacent to each other in the axial direction in the outer cylinder 2, the transmission gear 20 is formed by the receiving portion 3c. The diameter can be increased and the number of teeth can be increased while avoiding contact with the internal tooth pin 3 in the recessed space. As a result, a large reduction ratio can be obtained in the rotation transmission via the transmission gear 20.

  In the present embodiment, the receiving portion 3c of the internal tooth pin 3 is coaxial with the first meshing portion 3a and the second meshing portion 3b and is formed in a columnar shape having a smaller diameter than both the meshing portions 3a and 3b. Even if the internal tooth pin 3 rotates about the axis in the pin groove 2b on the inner surface of the outer cylinder 2, the amount of recess on the transmission gear 20 side of the receiving portion 3c of the internal tooth pin 3 can be kept constant. That is, even when the internal tooth pin 3 rotates around the axis, contact with the transmission gear 20 can be stably avoided at the receiving portion 3c of the internal tooth pin 3.

  In the present embodiment, the transmission gear 20 is externally fitted to the crankshaft 10 so as to be movable in the axial direction, and the transmission gear 20, the first external gear 14, and the second external gear 16 are a pair. Since the axial movement between the outer ring members 6a and 6a of the carrier bearings 6 and 6 is restricted, even if the crankshaft 10 is displaced in the axial direction, the transmission gear 20 has both the external gears 14 and 16. In place. For this reason, it is not necessary to increase the axial length of the receiving portion 3c of the internal tooth pin 3 by estimating the amount of axial movement of the transmission gear 20, and the minimum length substantially equal to the axial thickness of the transmission gear 20 Can be set to length. The displacement of the crankshaft 10 in the axial direction includes an error in the installation position of the crankshaft 10, washers 13b and 13d for holding the crankshaft 10 with respect to the carrier 4, the first crank bearing 12a, and the second crank. This is caused by respective dimensional errors of the bearing 12b and the retaining rings 13a and 13b, processing errors of the grooves 4k and 4m into which the retaining rings 13a and 13c are fitted, and the like.

  If the receiving part 3c is provided in the internal tooth pin 3, the axial direction length of the 1st meshing part 3a and the 2nd meshing part 3b will become small, and both the external gears 14 and 16 and both the meshing parts 3a and 3b However, in this embodiment, the axial length of the receiving portion 3c can be set to the minimum length as described above, so that both the external gears 14 and 16 and the both meshing portions can be set. A decrease in the contact area with 3a, 3b can be suppressed to a minimum, and an increase in surface pressure acting between both external gears 14, 16 and both meshing portions 3a, 3b can be suppressed. For this reason, it is possible to suppress the progress of wear and the like of the external gears 14 and 16 and the meshing portions 3a and 3b due to the increase in the surface pressure, and the external gears 14 and 16 and the internal pin 3 A reduction in lifetime can be suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

  For example, as in the first modification of the above-described embodiment shown in FIG. 4, the inner tooth pin 3 includes two straight tubular members 23 a and 23 b each formed separately and a columnar connecting member 23 c. The internal tooth pin 3 may be formed by press-fitting the connecting member 23c into the pipe members 23a, 23b and integrating the members 23a, 23b, 23c.

  Further, as in the second modification of the above-described embodiment shown in FIG. 5, the internal tooth pin 3 includes two straight tubular members 33 a and 33 b each formed separately and a stepped pin 33 c, The internal tooth pin 3 may be formed by fitting the pipe members 33a and 33b to the respective end portions of the stepped pin 33c.

  Further, as in the third modification of the embodiment shown in FIG. 6, the transmission gear 20 has one end in the axial direction of the crankshaft 10 rather than the first external gear 14 and the second external gear 16 aligned in the axial direction. You may arrange | position near the part. In the internal tooth pin 43, the receiving portion 43c may be provided at a position corresponding to the transmission gear 20 closer to one end portion in the axial direction than the first meshing portion 43a and the second meshing portion 43b arranged in the axial direction.

  Specifically, in the third modification, the transmission gear 20, the first external gear 14, and the second external gear 16 are arranged in this order in the axial direction in the closed space in the outer cylinder 2. Yes. The crankshaft 10 is provided with a first eccentric portion 10a and a second eccentric portion 10b adjacent to each other in the axial direction, and is positioned closer to one end portion in the axial direction than both the eccentric portions 10a and 10b. A fitted portion 10c is provided. The fitting portion 20b of the transmission gear 20 is externally fitted to the fitted portion 10c by spline coupling, and the first external gear 14 is attached to the first eccentric portion 10a via the first roller bearing 18a. The second external gear 16 is attached to the second eccentric portion 10b via the second roller bearing 18b.

  Further, the inner tooth pin 43 is provided with a first meshing portion 43a and a second meshing portion 43b continuously in the axial direction, and the first meshing portion 43a on the side opposite to the second meshing portion 43b. The receiving part 43c protrudes from the end surface so as to extend in the axial direction. Similarly to the above embodiment, the receiving portion 43c is coaxial with both the meshing portions 43a and 43b, and is formed in a columnar shape having a smaller diameter than both the meshing portions 43a and 43b. The outer peripheral end of the transmission gear 20 enters the recessed space formed by the receiving portion 43c.

  A fitted portion 10c is provided adjacent to the second external gear 16 on the opposite side of the first external gear 14 with respect to the second external gear 16 in the crankshaft 10, and the transmission gear 20 is externally connected to the fitted portion 10c. The first external gear 14, the second external gear 16, and the transmission gear 20 may be arranged in this order from one end side in the axial direction of the crankshaft 10. In this case, corresponding to the arrangement order of the gears 14, 16, and 20, the first meshing portion 43 a, the second meshing portion 43 b, and the receiving portion 43 c are provided in this order from the one end side in the axial direction in the internal tooth pin 43. It may be done.

  Further, the external fitting of the transmission gear 20 with respect to the crankshaft 10 is not limited to the spline coupling, but may be any other form of external fitting in which the transmission gear 20 is movable in the axial direction with respect to the crankshaft 10. For example, a key groove extending in the axial direction is formed in one of the fitted portion of the crankshaft 10 and the fitting portion of the transmission gear 20, and a key extending in the axial direction is formed in the other. The fitting portion of the transmission gear 20 may be externally fitted to the fitted portion of the crankshaft 10 so that the keyway and the key are fitted. Further, the transmission gear 20 may be fixed without moving in the axial direction with respect to the crankshaft 10.

  The number of external gears is not limited to two, and one or three or more external gears may be provided. In this case, the meshing portion of the internal pin that meshes with the external gear may be provided in the number and arrangement corresponding to the external gear.

  Further, as in the conventional gear device shown in FIG. 7, the configuration is such that the input rotation is transmitted from the transmission gear 118 provided on the crankshaft 104 to another crankshaft (not shown) via the cylindrical gear 116. The present invention can be applied.

It is sectional drawing along the axial direction of the eccentric rocking | fluctuation type gear apparatus by one Embodiment of this invention. It is sectional drawing along the II-II line of the eccentric rocking | fluctuation type gear apparatus shown in FIG. It is a perspective view of the internal tooth pin used for the eccentric rocking | fluctuation type gear apparatus shown in FIG. It is sectional drawing along the axial direction of the internal tooth pin by the 1st modification of one Embodiment of this invention. It is sectional drawing along the axial direction of the internal tooth pin by the 2nd modification of one Embodiment of this invention. It is a fragmentary sectional view along the axial direction of the eccentric rocking | fluctuation type gear apparatus by the 3rd modification of one Embodiment of this invention. It is sectional drawing along the axial direction of the eccentric rocking | fluctuation type gear apparatus by an example of the past.

Explanation of symbols

2 Outer cylinders 3, 43 Inner tooth pins 3a, 43a First engagement portions 3b, 43b Second engagement portions 3c, 43c Receiving portion 4 Carrier 4a Base portion (regulating member)
4b End plate (regulating member)
6 Carrier bearing 6a Outer ring member (regulating member)
6b Inner ring member (regulating member)
8a Input gear 10 Crankshaft 10a First eccentric portion 10b Second eccentric portion 14 First external gear 16 Second external gear 20 Transmission gear

Claims (4)

An outer cylinder provided with an inner tooth pin extending in the axial direction on the inner surface;
A crankshaft rotatably provided around the axis in the outer cylinder and having an eccentric part;
A transmission gear that is provided adjacent to the eccentric portion of the crankshaft in the axial direction and rotates integrally with the crankshaft about the same axis as the rotation shaft of the crankshaft;
An external gear attached to the eccentric portion of the crankshaft and oscillating and rotating in conjunction with the eccentric rotation of the eccentric portion while meshing with the internal tooth pin;
A carrier that is provided coaxially with the outer cylinder, and that rotates relative to the outer cylinder by transmitting the swing rotation of the external gear,
The internal tooth pin is provided adjacent to the meshing portion that meshes with the external gear and the meshing portion in the axial direction, and is recessed in a direction away from the rotation shaft of the transmission gear so as to receive the outer peripheral end of the transmission gear. An eccentric oscillating gear device having a receiving portion. The inner tooth pin is attached to the inner surface of the outer cylinder so as to be rotatable about an axis,
The meshing portion of the internal tooth pin is formed in a cylindrical shape having a predetermined diameter, while the receiving portion of the internal tooth pin is arranged coaxially with the meshing portion and has a smaller diameter than the meshing portion. The eccentric oscillating gear device according to claim 1, which is formed in a cylindrical shape. A plurality of the eccentric portions of the crankshaft are provided side by side in the axial direction of the crankshaft,
The external gear is attached to each of these eccentric parts,
The transmission gear is arranged in one place between the external gears,
A plurality of the meshing portions of the internal tooth pin are provided in the axial direction so as to mesh with the external gears, respectively, and the receiving portion of the internal tooth pin transmits the transmission between the meshing portions. The eccentric oscillating gear device according to claim 1 or 2, which is provided at a position corresponding to the gear. The transmission gear is externally fitted to the crankshaft so as to be movable in the axial direction,
The eccentric rocking | fluctuation type gearwheel of any one of Claims 1-3 provided with a pair of control member which pinches | interposes the said transmission gear and the said external gear from both axial directions, and controls the axial movement of these gears. apparatus.

Images