TW201420923A - Eccentrically oscillating gear device - Google Patents

Abstract

An eccentrically oscillating gear device (1) provided with an eccentric part (10a), an oscillating gear (14) having a through-hole into which the eccentricity part (10a) is inserted and having outer teeth (14a), an outer cylinder (2), and a carrier (4). The carrier (4) has a base part (5) in which a fastening hole (4f) is formed, an end plate part (7) in which a bolt through-hole (7c) is formed, and a bolt (9) inserted into the bolt through-hole (7c) and fastened in the fastening hole (4f). The bolt (9) is made from an iron-based material. The base part (5) is made from a material having a longitudinal elastic modulus lower than that of the iron-based material, such as an aluminum alloy. The outer cylinder (2) and the carrier (4) can be caused to concentrically rotate relative to each other by the oscillation of the oscillating gear (14) associated with the rotation of the eccentric part (10a).

Description

Eccentric swing gear device

The present invention relates to an eccentric oscillating gear device.

Conventionally, as disclosed in Patent Document 1 below, an eccentric oscillating type gear device that decelerates the number of revolutions between two opposing members at a specific reduction ratio is known. The eccentric oscillating gear device includes a carrier that is fixed to a counterpart member and a carrier that is disposed in the outer cylinder and that is fixed to the other partner member. The carrier has a base portion in which a shaft portion is integrally formed, and an end plate portion. A swing gear attached to the eccentric portion of the crankshaft is interposed between the substrate portion and the end plate portion, and in this state, the shaft portion and the end plate portion are fastened to each other by screws. Further, when the swing gear meshes with the inner teeth of the outer cylinder and rotates, the carrier rotates relative to the outer cylinder.

The substrate portion, the shaft portion, and the end plate portion constituting the carrier generally include an iron-based material, and the screws are also the same. The thread formed in the fastening hole of the shaft portion or the thread of the screw has a machining error. Therefore, when the screw is tightened, not all the portions of the screw are engaged. That is, there is a case where the distance between the threads is slightly uneven, and only a part of the threads are engaged. In this case, there is a problem that the tightening of the screw is caused when the carrier is subjected to an impact or the like.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-77980

It is an object of the present invention to prevent the screw provided to the carrier from loosening.

An eccentric oscillating type gear device according to an aspect of the present invention is a gear device that transmits a driving force between a first member and a second member by converting a number of revolutions at a specific number of revolutions. The eccentric oscillating gear device includes an eccentric portion; the oscillating gear has an insertion hole for inserting the eccentric portion, and has a tooth portion; and an outer cylinder that is attachable to one of the first member and the second member And configured to have internal teeth that mesh with the tooth portions of the swing gear; and a carrier that is configured to be attachable to the other of the first member and the second member. The carrier includes a base portion formed with a fastening hole, an end plate portion formed with a through hole, and a screw inserted into the insertion hole and fastened in the fastening hole. The above screw system contains an iron-based material. The base portion includes a material having a longitudinal elastic modulus lower than that of the iron-based material. The carrier and the outer cylinder are rotated by the eccentric portion, and the oscillating gear is oscillated while being engaged with the internal teeth.

1‧‧‧Eccentric swing gear device

2‧‧‧Outer tube

2a‧‧‧ inserted perforation

2b‧‧‧ pin slot

3‧‧‧ internal gear

4‧‧‧Gear rack

4a‧‧‧Substrate Department

4c‧‧‧Axis

4d‧‧‧through hole

4e‧‧‧ mounting holes

4f‧‧‧ fastening holes

4g‧‧‧ fastening holes

5‧‧‧ base

6‧‧‧A pair of main bearings

7‧‧‧End Plate Department

7a‧‧‧through hole

7b‧‧‧ crankshaft mounting holes

7c‧‧‧screw insertion

8‧‧‧ input shaft

8a‧‧‧ input gear

9‧‧‧ screws

10‧‧‧ crankshaft

10a‧‧‧1st eccentric

10b‧‧‧2nd eccentric

10c‧‧‧ axis body

10d‧‧‧Fitting Department

12a‧‧‧1st crank bearing

12b‧‧‧2nd crank bearing

14‧‧‧1st swing gear

14a‧‧‧1st external tooth

14b‧‧‧Central through hole

14c‧‧‧1st eccentric insertion punch

14d‧‧‧Axis insertion and perforation

16‧‧‧2nd swing gear

16a‧‧‧2nd external tooth

16b‧‧‧Central through hole

16c‧‧‧Second eccentric insertion piercing

16d‧‧‧Axis insertion piercing

18a‧‧‧1st roller bearing

18b‧‧‧2nd roller bearing

20‧‧‧Transmission gear

20a‧‧‧ external teeth

Fig. 1 is a cross-sectional view showing the configuration of an eccentric oscillating gear device according to an embodiment of the present invention.

Figure 2 is a cross-sectional view taken along line II-II of Figure 1.

Hereinafter, the eccentric oscillating gear device according to the embodiment of the present invention will be described in detail with reference to the drawings. The eccentric oscillating gear device (hereinafter referred to as a gear device) 1 of the present embodiment is applied as a reduction gear to, for example, a revolving unit such as a revolver or a wrist joint of a robot, and a revolving portion of various machine tools.

The gear device 1 of the present embodiment is configured such that the crankshaft 10 is rotated by rotating the input shaft 8, and the swing gears 14 and 16 are oscillated and rotated in conjunction with the eccentric portions 10a and 10b of the crankshaft 10, whereby the input is self-input. Rotation produces a decelerated output rotation. Thereby, for example, between the base of the robot (a counterpart member) and the body of revolution (the other partner member), a phase can be generated. Right to rotate. For example, the base member is exemplified by the first member, and for example, the swing system is exemplified by the second member.

As shown in FIGS. 1 and 2, the gear device 1 includes an outer cylinder 2, a carrier 4, an input shaft 8, a plurality of (for example, three) crankshafts 10, a first oscillating gear 14, a second oscillating gear 16, and a plurality of (for example, three) transmission gears 20.

The outer cylinder 2 constitutes the outer surface of the gear unit 1, and has a substantially cylindrical shape. A plurality of pin grooves 2b are formed in the inner circumferential surface of the outer cylinder 2. Each of the pin grooves 2b is disposed to extend 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 2b are arranged on the inner circumferential surface of the outer cylinder 2 at equal intervals in the circumferential direction.

The outer cylinder 2 has a plurality of inner tooth pins 3. Each of the internal tooth pins 3 is attached to the pin groove 2b. Specifically, each of the internal tooth pins 3 is fitted into the corresponding pin groove 2b, and is disposed in a posture extending in the axial direction of the outer tube 2. Thereby, the plurality of internal tooth pins 3 are arranged at equal intervals along the circumferential direction of the outer cylinder 2. In the internal tooth pins 3, the first external teeth 14a of the first oscillating gear 14 and the second external teeth 16a of the second oscillating gear 16 mesh.

The outer cylinder 2 is provided with a flange portion, and the flange portion forms an insertion hole 2a for inserting, for example, a fastening tool (screw) for fixing to the base of the robot.

The carrier 4 is housed in the outer cylinder 2 in a state in which it is disposed coaxially with the outer cylinder 2. The carrier 4 is relatively rotated about the same axis for the outer cylinder 2. Specifically, the carrier 4 is disposed on the inner side in the diameter direction of the outer cylinder 2, and in this state, one of the pair of main bearings 6 is provided to be relatively rotatable with respect to the outer cylinder 2 so as to be spaced apart from each other in the axial direction. .

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.

The substrate portion 4a is disposed in the vicinity of one end portion in the axial direction in the outer tube 2. A circular through hole 4d is provided in a central portion of the substrate portion 4a in the diameter direction. A plurality of (for example, three) crankshaft mounting holes 4e (hereinafter, simply referred to as mounting holes 4e) are provided at equal intervals in the circumferential direction around the through holes 4d.

In the substrate portion 4a, a fastening for fastening the fastening tool (screw) of the drawings is formed. A hole 4g for fixing the carrier 4 to, for example, a rotary body of a robot.

The end plate portion 7 is provided to be spaced apart from the substrate portion 4a in the axial direction, and is disposed in the outer tube 2 in the vicinity of the other end portion in the axial direction. A through hole 7a is provided in a central portion of the end plate portion 7 in the diameter direction. A plurality of (for example, three) crankshaft mounting holes 7b (hereinafter, simply referred to as mounting holes 7b) are provided around the through holes 7a at positions corresponding to the plurality of mounting holes 4e of the substrate portion 4a. In the outer cylinder 2, a closed space surrounded by the inner surfaces of the end plate portion 7 and the substrate portion 4a facing each other and the inner circumferential surface of the outer cylinder 2 is formed.

The plurality of shaft portions 4c are integrally provided with the substrate portion 4a, and linearly extend from one main surface (inner side surface) of the substrate portion 4a toward the end plate portion 7 side. The plurality of shaft portions 4c are disposed at equal intervals in the circumferential direction (see FIG. 2). Each of the shaft portions 4c is fastened to the end plate portion 7 by a screw 9 (see Fig. 1). In other words, the end plate portion 7 is formed with a screw insertion hole 7c, and the shaft portion 4c (base portion 4) is formed with a fastening hole 4f so as to extend in the axial direction from the front end surface thereof. Further, a screw 9 is inserted into the screw insertion hole 7c of the end plate portion 7 from the side opposite to the base portion 4. The screw 9 is screwed to the fastening hole 4f of the shaft portion 4c. Thereby, the substrate portion 4a, the shaft portion 4c, and the end plate portion 7 are integrated.

The input shaft 8 functions as an input unit that inputs a driving force of a drive motor (not shown). The input shaft 8 is inserted into the through hole 7a of the end plate portion 7 and the through hole 4d of the substrate portion 4a. The input shaft 8 is disposed such that its axis coincides with the axis of the outer cylinder 2 and the carrier 4, and rotates around the shaft. An input gear 8a is provided on the outer peripheral surface of the front end of the input shaft 8.

A plurality of crankshafts 10 are arranged in the outer cylinder 2, and are arranged at equal intervals around the input shaft 8 (see Fig. 2). Each of the crankshafts 10 is supported by a pair of crank bearings 12a and 12b so as to be rotatable about the carrier 4 (see Fig. 1). Specifically, the first crank bearing 12a is attached to the inner side in the axial direction with a predetermined length from one end of the crankshaft 10 in the axial direction, and the first crank bearing 12a is attached to the mounting hole 4e of the substrate portion 4a. On the other hand, the second crank bearing 12b is attached to the other end portion of the crankshaft 10 in the axial direction, and the second crank bearing 12b is attached to the mounting hole 7b of the end plate portion 7. Thereby, the crankshaft 10 is rotatably supported by the substrate portion 4a and the end Plate section 7.

Each of the crankshafts 10 includes a shaft body 10c and eccentric portions 10a and 10b integrally formed in the shaft body 10c. The first eccentric portion 10a and the second eccentric portion 10b are arranged in the axial direction so as to be arranged between the portions supported by the two crank bearings 12a and 12b. Each of the first eccentric portion 10a and the second eccentric portion 10b has a cylindrical shape and is extended from the shaft main body 10c to the outer side in the radial direction in a state of being eccentric with respect to the axial center of the shaft main body 10c. The first eccentric portion 10a and the second eccentric portion 10b are respectively eccentric from the axial center by a specific eccentric amount, and are disposed so as to have a phase difference of a specific angle.

A fitting portion 10d to which the transmission gear 20 is attached is provided at one end portion of the crankshaft 10, that is, a portion of the portion of the mounting portion 4e that is attached to the mounting hole 4e of the substrate portion 4a.

The first oscillating gear 14 is disposed in the closed space in the outer cylinder 2, and is attached to the first eccentric portion 10a of each of the crankshafts 10 via the first roller bearing 18a. When the first eccentric portion 10a is eccentrically rotated, the first oscillating gear 14 rotates in conjunction with the eccentric rotation while engaging the internal tooth pin 3 in conjunction with the eccentric rotation.

The first oscillating gear 14 has a size slightly smaller than the inner diameter of the outer cylinder 2. The first oscillating gear 14 includes a first outer tooth 14a, a central portion through hole 14b, a plurality of (for example, three) first eccentric portion insertion holes 14c, and a plurality of (for example, three) shaft portion insertion holes 14d. The first outer teeth 14a have a wave shape that is smoothly and continuously continuous throughout the circumferential direction of the swing gear 14.

The center portion through hole 14b is provided at a central portion in the diameter direction of the first swing gear 14. The input shaft 8 is inserted through the center through hole 14b with a margin.

The plurality of first eccentric portion insertion holes 14c are attached to the first oscillating gear 14, and are provided at equal intervals in the circumferential direction around the center portion through hole 14b. The first eccentric portion is inserted into the through hole 14c, and the first eccentric portion 10a of each of the crankshafts 10 is inserted into the first roller bearing 18a.

The plurality of shaft insertion holes 14d are attached to the first swing gear 14, and are disposed at equal intervals in the circumferential direction around the center portion through hole 14b. Each of the shaft insertion holes 14d is disposed at a position between the adjacent first eccentric portion insertion holes 14c in the circumferential direction. Inserting a perforation 14d into each shaft portion to have The state of the margin is inserted through the corresponding shaft portion 4c.

The second oscillating gear 16 is disposed in the closed space in the outer cylinder 2, and is attached to the second eccentric portion 10b of each of the crankshafts 10 via the second roller bearing 18b. The first oscillating gear 14 and the second oscillating gear 16 are arranged in the axial direction in accordance with the arrangement of the first eccentric portion 10a and the second eccentric portion 10b. When the second eccentric portion 10b is eccentrically rotated, the second oscillating gear 16 rotates in conjunction with the eccentric rotation while engaging the internal tooth pin 3 in conjunction with the eccentric rotation.

The second oscillating gear 16 has a size slightly smaller than the inner diameter of the outer cylinder 2, and has the same configuration as that of the first oscillating gear 14. In other words, the second oscillating gear 16 includes the second external teeth 16a, the central portion through hole 16b, a plurality of (for example, three) second eccentric portion insertion through holes 16c, and a plurality of (for example, three) shaft portion insertion through holes 16d. These have the same configuration as the first external teeth 14a of the first oscillating gear 14, the central portion through hole 14b, the plurality of first eccentric portion insertion holes 14c, and the plurality of shaft portion insertion holes 14d. The second eccentric portion 10c is inserted into each of the second eccentric portions, and the second eccentric portion 10b of the crankshaft 10 is inserted through the second roller bearing 18b.

Each of the transmission gears 20 transmits the rotation of the input gear 8a to the corresponding crankshaft 10. Each of the transmission gears 20 is externally fitted to the fitted portion 10d provided at one end of the shaft body 10c of the corresponding crankshaft 10. Each of the transmission gears 20 is rotatable integrally with the crankshaft 10 about the same axis as the rotation axis of the crankshaft 10. Each of the transmission gears 20 has teeth 20a that mesh with the input gear 8a.

Here, the materials constituting the carrier 4 and the outer cylinder 2 will be described.

The base portion 5 of the carrier 4 (i.e., the substrate portion 4a and the shaft portion 4c) and the outer cylinder 2 respectively contain aluminum or an aluminum alloy. Further, the end plate portion 7 of the carrier 4 also contains aluminum or an aluminum alloy. On the other hand, the screw 9 for fastening the base portion 5 and the end plate portion 7 includes an iron-based material such as stainless steel or chrome-molybdenum steel. Further, the base portion 5 is not limited to containing aluminum or an aluminum alloy, and may alternatively include a material having a longitudinal elastic modulus such as a fiber-reinforced plastic or a magnesium alloy that is lower than a longitudinal elastic modulus of the iron-based material.

As described above, in the gear device 1 of the present embodiment, the carrier 4 is configured and The shaft portion 4c of the base portion 5 in which the fastening hole 4f for fastening the screw 9 is formed is made of aluminum or aluminum alloy, and the screw 9 contains an iron-based material. Therefore, the shaft portion 4c of the base portion 5 is softer than the screw 9. Therefore, when the screw 9 inserted into the screw insertion hole 7c of the end plate portion 7 is screwed to the fastening hole 4f of the shaft portion 4c, the thread of the fastening hole 4f is easily elastically deformed. Therefore, even if there is a slightly different portion between the threads due to the machining error, the portion of the thread of the fastening hole 4f can be elastically deformed, and the thread can be integrally formed in the axial direction of the screw. Engage equally with each other. Therefore, it is possible to prevent the thread of the screw 9 and the thread of the fastening hole from being engaged only by the portion, so that the screw 9 can be prevented from being loosened when the carrier 4 is subjected to an impact or the like.

Further, in the present embodiment, since the outer cylinder 2 is also made of aluminum or aluminum alloy, the weight of the gear unit 1 can be reduced. Moreover, it can be less susceptible to magnetic fields. Further, the heat transfer performance of the outer cylinder 2 can be improved, and therefore, the heat inside the outer cylinder 2 can be easily released. Therefore, the temperature rise of the swing gears 14, 16 can be suppressed, and the thermal expansion of the swing gears 14, 16 can be suppressed. As a result, the surface pressure of the tooth portions 14a and 16a of the swing gears 14 and 16 can be suppressed from increasing, so that the service life of the swing gears 14 and 16 can be extended.

The present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the spirit of the invention. For example, the above embodiment is configured such that two swing gears 14 and 16 are provided, but the present invention is not limited thereto. For example, a configuration in which one swing gear is provided or three or more swing gears may be provided.

In the above embodiment, the input shaft 8 is disposed at the center of the carrier 4, and a plurality of the crankshafts 10 are disposed around the input shaft 8, but the present invention is not limited thereto. For example, the crankshaft 10 may be disposed in the middle crank type of the center portion of the carrier 4 in the diameter direction. In this case, if the input shaft 8 is provided to be engageable with the transmission gear 20 mounted on the crankshaft 10, the input shaft 8 can be disposed at any position.

Here, the above embodiment will be outlined.

(1) In the present embodiment, the carrier is formed and a fastening hole for fastening the screw is formed. The base includes a material having a lower longitudinal modulus than the iron-based material, and the screw contains an iron-based material. Therefore, the base is softer than the screw. Therefore, when the screw inserted into the insertion hole of the end plate portion is fastened to the base, the thread of the fastening hole is easily elastically deformed. Therefore, even if there is a slightly different portion between the threads due to the machining error, the portion of the thread of the fastening hole can be elastically deformed by the strong portion of the thread of the fastening hole, and the threads can be made equal to each other throughout the axial direction of the thread. Ground engagement. Therefore, it is possible to prevent the thread of the screw and the thread of the fastening hole from being engaged only in the part, thereby preventing the screw from being loosened when the carrier is subjected to an impact or the like.

(2) Further, in the material having a lower longitudinal elastic modulus than the iron-based material, for example, aluminum or an aluminum alloy may be used as the base material. Aluminum alloys are lightweight and market accessibility is also preferred.

(3) The outer cylinder may be made of aluminum or aluminum alloy. In this aspect, the weight reduction of the eccentric oscillating gear device can be further achieved. Moreover, it can be less susceptible to magnetic fields. Further, the heat transfer performance of the outer cylinder can be improved, and therefore, the heat inside the outer cylinder can be easily released. Therefore, the temperature rise of the swing gear can be suppressed, and the thermal expansion of the swing gear can be suppressed. As a result, the increase in the surface pressure of the tooth portion of the swing gear can be suppressed, so that the service life of the swing gear can be extended.

As described above, according to the present embodiment, it is possible to prevent the screw provided on the carrier from being loosened.

1‧‧‧Eccentric swing gear device

2‧‧‧Outer tube

2a‧‧‧ inserted perforation

2b‧‧‧ pin slot

3‧‧‧ internal gear

4‧‧‧Gear rack

4a‧‧‧Substrate Department

4c‧‧‧Axis

4d‧‧‧through hole

4e‧‧‧ mounting holes

4f‧‧‧ fastening holes

4g‧‧‧ fastening holes

5‧‧‧ base

6‧‧‧A pair of main bearings

7‧‧‧End Plate Department

7a‧‧‧through hole

7b‧‧‧ crankshaft mounting holes

7c‧‧‧screw insertion

8‧‧‧ input shaft

8a‧‧‧ input gear

9‧‧‧ screws

10‧‧‧ crankshaft

10a‧‧‧1st eccentric

10b‧‧‧2nd eccentric

10c‧‧‧ axis body

10d‧‧‧Fitting Department

12a‧‧‧1st crank bearing

12b‧‧‧2nd crank bearing

14‧‧‧1st swing gear

14a‧‧‧1st external tooth

14b‧‧‧Central through hole

14c‧‧‧1st eccentric insertion punch

14d‧‧‧Axis insertion and perforation

16‧‧‧2nd swing gear

16a‧‧‧2nd external tooth

16b‧‧‧Central through hole

16c‧‧‧Second eccentric insertion piercing

16d‧‧‧Axis insertion piercing

18a‧‧‧1st roller bearing

18b‧‧‧2nd roller bearing

20a‧‧‧ external teeth

Claims (3)

An eccentric oscillating type gear device is a gear device that transmits a driving force between a first member and a second member by a specific number of revolutions, and includes: an eccentric portion; a swing gear having the above The eccentric portion is inserted into the through hole and has a tooth portion; and the outer tube is configured to be attachable to one of the first member and the second member, and has a meshing engagement with the tooth portion of the swing gear The internal gear; and the carrier are configured to be attachable to the other of the first member and the second member; the carrier includes: a base portion formed with a fastening hole, and an end formed with a through hole a plate portion and a screw inserted into the insertion hole and fastened in the fastening hole, wherein the screw comprises an iron-based material, and the base portion comprises a material having a longitudinal elastic modulus lower than a longitudinal elastic modulus of the iron-based material The carrier and the outer cylinder are rotated by the eccentric portion, and the oscillating gear is oscillated while being engaged with the internal teeth to rotate relative to each other. The eccentric oscillating gear device of claim 1, wherein the base is made of aluminum or aluminum alloy. The eccentric oscillating gear device according to claim 1 or 2, wherein the outer cylinder is made of aluminum or aluminum alloy.