JP2015021555A - Eccentric oscillation type gear device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a degree of freedom in designing the inside of a gear device while easing concentration of stress by force received from a bolt fastening an end plate portion and a shaft portion.SOLUTION: An eccentric oscillation type gear device 1 includes an eccentric portion 10a, an oscillation gear 14 having an external tooth 14a and interlocked with the eccentric portion 10a, an outer cylindrical portion 2 having an internal tooth pin 3 engaged with the external tooth 14a of the oscillation gear 14, and a carrier 4 relatively rotated to the outer cylindrical portion 2 while interlocked with oscillation rotation of the oscillation gear 14. The carrier 4 has a base portion 5 having a base plate portion 4a and a shaft portion 4c extending from the base plate portion 4a, and an end plate portion 7 fastened to the shaft portion 4c by a bolt 9. A fastening hole 4f formed on the shaft portion 4c is provided with a relief portion 30 to be free from contact with a tip portion of the bolt 9.

Description

  The present invention relates to an eccentric oscillating gear device.

  Conventionally, as disclosed in Patent Document 1 below, an eccentric oscillating gear device that reduces the rotational speed at a predetermined reduction ratio between two mating members is known. As shown in FIG. 3, the eccentric oscillating gear device disclosed in Patent Document 1 is provided with an outer cylindrical portion 62 fixed to one counterpart member, an inner cylindrical portion 62 and the other cylindrical portion 62. And a carrier 64 fixed to the mating member. A pair of main bearings 66 is disposed between the outer cylindrical portion 62 and the carrier 64. The carrier 64 has a base portion in which a substrate portion 64a and a shaft portion 64c extending from the substrate portion 64a are integrally formed, and an end plate portion 64b formed separately from the base portion. . Two swing gears 68 are sandwiched between the substrate portion 64a and the end plate portion 64b, and these swing gears 68 are attached to the eccentric portions 70a and 70b of the crankshaft 70. In this state, the shaft portion 64 c and the end plate portion 64 b are fastened to each other by the bolt 72.

JP 2009-14039 A

  In the eccentric oscillating gear device disclosed in Patent Document 1, the shaft portion 64 c and the end plate portion 64 b are fastened to each other by a bolt 72. For this reason, when an external force is applied to the eccentric oscillating gear device, the shaft portion 64c may be bent or twisted with respect to the substrate portion 64a. In this case, since the fastening hole 64d is a screw hole, when the fastening hole 64d is pressed by the thread of the bolt 72, stress concentration is caused. Therefore, in order to ensure sufficient strength against the force received from the tip of the bolt 72, the shaft portion 64c needs to be thick. However, if the shaft portion 64c is thickened, there is a problem that the degree of freedom in designing the gear device is reduced.

  Therefore, the present invention has been made in view of the above-described prior art, and an object of the present invention is to reduce the stress concentration due to the force received from the bolt that fastens the end plate portion and the shaft portion, while reducing the stress concentration inside the gear device. This is to improve the degree of freedom of design.

  To achieve the above object, the present invention provides an eccentric portion, a swing gear having a tooth portion and interlocking with the eccentric portion, and an outer cylinder portion having an inner tooth meshing with the tooth portion of the swing gear. An inner cylinder portion that generates relative rotation with respect to the outer cylinder portion in conjunction with the oscillating rotation of the oscillating gear, and the inner cylinder portion includes a base portion having a substrate portion and a shaft portion extending from the substrate portion; And an end plate portion fastened to the shaft portion by a bolt, and a fastening hole formed in the shaft portion is provided with a relief portion so that the tip end portion of the bolt does not come into contact with the fastening hole. This is an eccentric oscillating gear device.

  In the present invention, an escape portion is provided for avoiding the front end portion of the bolt from coming into contact with a fastening hole into which a bolt for fastening the shaft portion and the end plate portion is screwed. For this reason, when an external force acts on the eccentric oscillating gear device and the shaft portion is bent or twisted with respect to the substrate portion, the tip of the bolt comes into contact with the fastening hole. You can avoid that. For this reason, it can avoid that the stress which arises by the force received from the front-end | tip part of a volt | bolt concentrates in a fastening hole. Therefore, it is not necessary to form the shaft portion thick in order to increase the strength. Therefore, the freedom degree of design inside a gear apparatus can be improved.

  Here, the escape portion may be formed so as to be connected to an end portion of the fastening hole, and a tip portion of the bolt may enter the escape portion. In this aspect, the front-end | tip part of the volt | bolt inserted in the fastening hole passes over the fastening hole, and has entered into the escape part. Therefore, it can prevent reliably that the front-end | tip part of a volt | bolt contacts a fastening hole.

  The escape portion may be expanded in diameter with respect to the fastening hole. In this aspect, since the escape portion is enlarged in diameter with respect to the fastening hole, even when an external force that bends the shaft portion is applied, the tip of the bolt is prevented from contacting the escape portion. be able to.

  The peripheral surface of the escape portion may be formed by a peripheral surface without unevenness. In this aspect, since the peripheral surface of the relief portion is formed by a peripheral surface without unevenness, it is possible to prevent the processing for forming the relief portion from becoming complicated. Moreover, when the shaft portion is deformed, it is possible to prevent stress concentration due to the unevenness of the peripheral surface from occurring.

  The escape portion and the fastening hole may be formed to be continuous with each other and penetrate the base portion. In this aspect, since the relief portion and the fastening hole are formed so as to be continuous and pass through the base portion, it is possible to prevent the processing for forming the relief portion from becoming complicated.

  As described above, according to the present invention, it is possible to alleviate the stress concentration due to the force received from the bolt that fastens the end plate portion and the shaft portion, and to improve the degree of freedom of design inside the gear device. it can.

It is a figure which shows the structure of the eccentric rocking | fluctuation type gear apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the eccentric rocking | fluctuation type gear apparatus which concerns on other embodiment of this invention. It is a figure which shows the structure of the conventional eccentric rocking | fluctuation type gear apparatus.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. An eccentric oscillating gear device (hereinafter referred to as a gear device) 1 according to this embodiment is applied as a speed reducer to, for example, a revolving part of a revolving trunk or arm joint of a robot, a revolving part of various machine tools, or the like. is there.

  The gear device 1 according to the present embodiment rotates the oscillating gear 14 by rotating the eccentric portion 10a of the crankshaft 10 so as to obtain an output of the rotational speed reduced from the input rotational speed. It is configured. Thereby, for example, relative rotation can be caused between the base (first mating member) of the robot and the turning drum (second mating member).

  As shown in FIG. 1, the gear device 1 includes an outer cylinder portion 2, a carrier 4 as an inner cylinder portion, a plurality of (for example, three) crankshafts 10, and a swing gear 14.

  The outer cylinder part 2 comprises the outer surface of the gear apparatus 1, and has a substantially cylindrical shape. A large number of pin grooves 2 b are formed on the inner peripheral surface of the outer cylindrical portion 2. Each pin groove 2b is disposed so as to extend in the axial direction of the outer cylindrical portion 2, and has a semicircular cross-sectional shape in a cross section orthogonal to the axial direction. These pin grooves 2 b are arranged on the inner peripheral surface of the outer cylinder portion 2 at equal intervals in the circumferential direction.

  The outer cylinder portion 2 has a large number of internal tooth pins 3. Each internal tooth pin 3 is attached to a pin groove 2b. Specifically, each internal tooth pin 3 is fitted in the corresponding pin groove 2 b and is arranged in a posture extending in the axial direction of the outer cylinder portion 2. Thereby, the many internal tooth pins 3 are arranged at equal intervals along the circumferential direction of the outer cylinder part 2. The external teeth (tooth portions) 14 a of the swing gear 14 mesh with these internal tooth pins 3.

  The outer cylinder portion 2 is provided with a flange portion. The flange portion is formed with an insertion hole 2a for inserting a fastener (bolt) for fixing to the base of the robot, for example.

  The carrier 4 is accommodated in the outer cylinder part 2 in a state of being arranged coaxially with the outer cylinder part 2. The carrier 4 rotates relative to the outer cylinder portion 2 around the same axis. Specifically, the carrier 4 is disposed on the radially inner side of the outer cylinder portion 2, and in this state, the carrier 4 is relatively opposed to the outer cylinder portion 2 by a pair of main bearings 6 provided to be separated from each other in the axial direction. It is rotatably supported. An annular seal member 25 is provided between the outer cylinder portion 2 and the carrier 4.

  The carrier 4 includes a base portion 5 having a substrate portion 4a and a plurality of (for example, three) shaft portions 4c, and an end plate portion 7 formed separately from the base portion 5.

  The substrate portion 4a is disposed in the vicinity of one end portion in the axial direction in the outer cylinder portion 2. A through hole 4d having a circular cross section is provided in the central portion in the radial direction of the substrate portion 4a. Around the through hole 4d, a plurality (for example, three) of crankshaft holes 4e are provided at equal intervals in the circumferential direction.

  A fastening hole 4g for fastening a fastener (bolt) (not shown) for fixing the carrier 4 to, for example, a revolving drum of the robot is formed in the substrate portion 4a.

  The end plate portion 7 is provided to be separated from the substrate 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 portion 2. A through hole 7 a having a circular cross section is provided in the radial center of the end plate portion 7. Around the through hole 7a, a plurality of (for example, three) crankshaft holes 7b are provided at positions corresponding to the plurality of crankshaft holes 4e of the substrate portion 4a.

  The plurality of shaft portions 4c are provided integrally with the substrate portion 4a, and linearly extend from one main surface (inner surface) of the substrate portion 4a to the end plate portion 7 side. The plurality of shaft portions 4c are arranged at equal intervals in the circumferential direction.

  The end plate portion 7 is fastened to the base portion 5 by bolts 9. That is, a bolt insertion hole 7c is formed in the end plate portion 7, and a fastening hole 4f is formed in the shaft portion 4c (base portion 5) so as to extend in the axial direction from the distal end surface. A bolt 9 is inserted into the bolt insertion hole 7c of the end plate portion 7 from the side opposite to the base portion 5 (substrate portion 4a). The bolt 9 is screwed into the fastening hole 4f of the shaft portion 4c. Thereby, the board | substrate part 4a, the shaft part 4c, and the end plate part 7 are integrated. That is, the end plate portion 7 is detachably coupled to the substrate portion 4a.

  The fastening hole 4f formed in the shaft part 4c (base part 5) is formed with a relief part 30 for preventing the tip of the bolt 9 from coming into contact with the fastening hole 4f. The escape portion 30 is formed so as to be continuous with the end portion on the back side of the fastening hole 4f and to extend straight from the end portion in the axial direction of the fastening hole 4f.

  The escape portion 30 is formed by a bottomed hole that is expanded with respect to the fastening hole 4f, and the inner diameter of the escape portion 30 is substantially constant in the axial direction. That is, the space in the escape portion 30 is a columnar space with rounded corners.

  The escape portion 30 is formed in such a size that the end opposite to the fastening hole 4f is located in the shaft portion 4c. That is, the escape portion 30 is located not in the substrate portion 4a but in the shaft portion 4c. And in the escape part 30, the edge part on the opposite side to the fastening hole 4f is located in the vicinity of the root of the shaft part 4c in the axial direction. The escape portion 30 may be formed so as to extend from the shaft portion 4c to the substrate portion 4a.

  The axial length of the fastening hole 4 f is shorter than the length of the male thread portion of the bolt 9. For this reason, when the bolt 9 is screwed into the fastening hole 4 f, the tip portion enters the escape portion 30. That is, the front end portion of the male screw portion of the bolt 9 is not screwed into the fastening hole 4f.

  As described above, when the escape portion 30 is expanded in diameter with respect to the fastening hole 4f and the front end portion of the bolt 9 enters the escape portion 30, an external force that bends the shaft portion 4c is applied. In addition, it is possible to prevent the peripheral surface 30 a of the escape portion 30 from being pressed by the thread of the bolt 9.

  Furthermore, unlike the fastening hole 4f, the escape portion 30 is not a hole with an uneven surface like a screw hole, but is a hole without an uneven surface on the peripheral surface 30a. Since unevenness is not formed on the peripheral surface 30a of the escape portion 30, it is possible to prevent stress concentration due to the unevenness of the peripheral surface 30a from occurring when the shaft portion 4c is deformed.

  A pin hole 22 is formed in the base part 5 and the end plate part 7, and the positioning pin 11 is inserted into the pin hole 22 from the end plate part 7 to the base part 5. Thereby, the position of the end plate part 7 with respect to the base part 5 is determined with high accuracy.

  The plurality of crankshafts 10 are arranged at equal intervals around the central through holes 4d and 7a in the outer cylinder portion 2. Each crankshaft 10 is supported by a pair of crank bearings 12a and 12b so as to be rotatable about the axis with respect to the carrier 4.

  Specifically, each crankshaft 10 has a first crank bearing 12a attached to a portion on the side of the substrate portion 4a in the axial direction, and the first crank bearing 12a is placed in the crankshaft hole 4e of the substrate portion 4a. Has been placed. Further, each crankshaft 10 is provided with a second crank bearing 12b at a position on the end plate portion 7 side in the axial direction, and the second crank bearing 12b is placed in the crankshaft hole 7b of the end plate portion 7. Has been placed. Thereby, the crankshaft 10 is rotatably supported by the board | substrate part 4a and the end plate part 7. FIG.

  Each crankshaft 10 includes a shaft main body 10c and an eccentric portion 10a formed integrally with the shaft main body 10c. In the present embodiment, the two eccentric portions 10a are arranged so as to be aligned in the axial direction between the portions supported by both the crank bearings 12a and 12b. The eccentric part 10a has a cylindrical shape, and protrudes radially outward from the shaft body 10c in a state of being eccentric with respect to the axis of the shaft body 10c. The two eccentric portions 10a are each eccentric from the shaft center by a predetermined amount of eccentricity, and are arranged so as to have a phase difference of a predetermined angle.

  The shaft main body 10c has a first journal portion 10f on the substrate portion side with respect to the eccentric portion 10a and a second journal portion 10g on the end plate portion side with respect to the eccentric portion 10a. A first crank bearing 12a is attached to the first journal portion 10f, and a second crank bearing 12b is attached to the second journal portion 10g.

  The second journal portion 10g extends in the axial direction, and the transmission gear 20 is attached to this portion. The transmission gear 20 meshes with an input gear (not shown) and transmits a rotational driving force input through the input gear to the crankshaft 10.

  The oscillating gear 14 is attached to the eccentric portion 10a of the crankshaft 10 via a roller bearing 18a. Therefore, in this embodiment, the two rocking gears 14 are provided so as to be aligned in the axial direction. When each crankshaft 10 rotates and the eccentric portion 10a rotates eccentrically, the oscillating gear 14 oscillates and rotates while meshing with the internal tooth pin 3 in conjunction with the eccentric rotation.

  The oscillating gear 14 has a size slightly smaller than the inner diameter of the outer cylinder portion 2. The oscillating gear 14 has external teeth 14a, a central through hole 14b, a plurality (for example, three) of eccentric portion insertion holes 14c, and a plurality of (for example, three) shaft portion insertion holes 14d. . The external teeth 14 a have a wave shape that smoothly continues over the entire circumferential direction of the oscillating gear 14. The central through hole 14 b is provided in the central portion in the radial direction of the rocking gear 14.

  The plurality of eccentric portion insertion holes 14 c are provided at equal intervals in the circumferential direction around the central portion through hole 14 b in the swing gear 14. The eccentric portions 10a of the respective crankshafts 10 are inserted into the respective eccentric portion insertion holes 14c with the roller bearings 18a interposed therebetween.

  The plurality of shaft portion insertion holes 14 d are provided at equal intervals in the circumferential direction around the central portion through hole 14 b in the swing gear 14. Each shaft portion insertion hole 14d is disposed at a position between adjacent eccentric portion insertion holes 14c in the circumferential direction. The corresponding shaft portion 4c is inserted into each shaft portion insertion hole 14d with play.

  In this gear device 1, when each crankshaft 10 is rotated by the rotation of the transmission gear 20, the swing gear 14 attached to the eccentric portion 10a is engaged with the internal tooth pin 3 as the eccentric portion 10a rotates. Swing. As the meshing position changes sequentially, the carrier 4 and the outer cylinder part 2 rotate relative to each other. Thereby, the output of the rotation speed decelerated from the input rotation speed is obtained.

  As described above, in the present embodiment, the bolt 9 for fastening the shaft portion 4c and the end plate portion 7 is screwed into the fastening hole 4f, and the tip of the bolt 9 is on the inner peripheral surface of the fastening hole 4f. An escape portion 30 for avoiding contact is provided. For this reason, when an external force acts on the gear device 1 and the shaft portion 4c is deformed so as to be bent or twisted with respect to the substrate portion 4a, the tip end portion of the bolt 9 contacts the fastening hole 4f. It is possible to avoid contact. For this reason, in the fastening hole 4f, it is possible to avoid the concentration of stress caused by the force received from the tip of the bolt 9. Therefore, it is not necessary to form the base of the shaft portion 4c thick in order to increase the strength. Therefore, the freedom degree of design inside the gear apparatus 1 can be improved.

  Moreover, in the present embodiment, the tip end portion of the bolt 9 inserted into the fastening hole 4f passes through the fastening hole 4f and enters the escape portion 30. Therefore, it can prevent reliably that the front-end | tip part of the volt | bolt 9 contacts the fastening hole 4f.

  Further, in this embodiment, since the escape portion 30 is formed by a hole whose diameter is increased with respect to the fastening hole 4f, the tip of the bolt 9 can be used even when an external force is applied to bend the shaft portion 4c. It is possible to reliably prevent the portion from coming into contact with the escape portion 30. Moreover, since the peripheral surface 30a of the escape portion 30 is formed by a peripheral surface without unevenness, and the escape portion 30 extends straight in the axial direction of the fastening hole 4f, the processing for forming the escape portion 30 becomes complicated. Can be prevented. Moreover, when the shaft part 4c deform | transforms, it can prevent that the stress concentration resulting from the unevenness | corrugation of the surrounding surface 30a generate | occur | produces.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention. For example, as shown in FIG. 2, the relief portion 30 and the fastening hole 4 f may be formed so as to be continuous, and the relief portion 30 may penetrate the base portion 5. That is, one end portion of the escape portion 30 is connected to the fastening hole 4f, and the other end portion opens to the outer surface 4h of the substrate portion 4a. The escape portion 30 is formed in a shape extending straight in the axial direction of the fastening hole 4f. In this case, in order to perform the processing for forming the escape portion 30, a hole can be formed from the outer surface 4h side of the substrate portion 4a.

  In this aspect, since the escape portion 30 and the fastening hole 4f penetrate the base portion 5, it is possible to prevent the process of forming the escape portion 30 from becoming complicated.

  In the above-described embodiment, the crankshaft 10 has a portion protruding toward the end plate portion 7 and the transmission gear 20 is disposed on the end plate portion 7 side. However, the present invention is not limited thereto. The crankshaft 10 may have a portion that protrudes toward the substrate portion 4a, and the transmission gear 20 may be disposed on the substrate portion 4a side.

  In the above embodiment, the two oscillating gears 14 are provided. However, the present invention is not limited to this. For example, a configuration in which one oscillating gear is provided or a configuration in which three or more oscillating gears are provided may be employed.

  In the above embodiment, the plurality of crankshafts 10 are arranged around the central through holes 4d and 7a. However, the present invention is not limited to this. For example, a center crank type in which one crankshaft 10 is disposed at the center of the carrier 4 may be used.

  In the above-described embodiment, an example is shown in which the carrier 4 is fastened to the revolving cylinder and revolved, and the outer cylinder portion 2 is fixed to the base of the robot so as to be immovable. That is, the outer cylinder part 2 may be fastened to the revolving drum and the carrier 4 may be fastened to the base of the robot. In this case, the outer cylinder portion 2 rotates relative to the carrier 4 so that the turning cylinder of the robot turns with respect to the base.

DESCRIPTION OF SYMBOLS 1 Eccentric rocking gear apparatus 2 Outer cylinder part 3 Internal tooth pin 4 Carrier 4a Base plate part 4c Shaft part 4f Fastening hole 4h Outer surface 5 Base 6 Main bearing 7 End plate part 9 Bolt 10 Crankshaft 10a Eccentric part 10c Shaft body 14 Shaking Dynamic gear 14a External tooth 30 Escape part 30a Circumferential surface

Claims (5)

An eccentric part,
A swing gear having a tooth portion and interlocking with the eccentric portion;
An outer cylinder portion having an inner tooth meshing with the tooth portion of the swing gear;
An inner cylinder portion that generates relative rotation with respect to the outer cylinder portion in conjunction with the oscillating rotation of the oscillating gear,
The inner cylinder portion has a base portion having a substrate portion and a shaft portion extending from the substrate portion, and an end plate portion fastened to the shaft portion by a bolt,
An eccentric oscillating gear device in which an escape portion is provided in a fastening hole formed in the shaft portion so that a tip portion of the bolt does not contact.   The eccentric oscillating gear device according to claim 1, wherein the escape portion is formed so as to be connected to an end portion of the fastening hole, and a tip portion of the bolt enters the escape portion.   The eccentric oscillating gear device according to claim 1, wherein the escape portion has a diameter enlarged with respect to the fastening hole.   The eccentric oscillating gear device according to claim 3, wherein a peripheral surface of the relief portion is formed by a peripheral surface having no unevenness.   The eccentric oscillating gear device according to any one of claims 1 to 4, wherein the relief portion and the fastening hole are formed so as to be continuous and penetrate the base portion.

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