JP2009287631A - Eccentric oscillation type gear device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the shaft diameter of an input shaft, while suppressing enlargement in size in a radial direction of a part supporting the input shaft. <P>SOLUTION: An eccentric oscillation type gear device includes: a first bearing 56 constituted of a cylindrical roller bearing, and rotatably supporting the input shaft 16 with respect to an end plate 30; a second bearing 57 constituted of a tapered roller bearing and rotatably supporting the input shaft 16 with respect to a base plate part 32; a third bearing 58 constituted of a tapered roller bearing having an inclination direction receiving a load opposite to that of a second bearing 57, and rotatably supporting the input shaft 16 with respect to the base plate part 32. A part of the second bearing 57 is disposed in a through-hole 50a of an external gear 50 together with the input shaft 16. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an eccentric oscillating gear device.

  Conventionally, as disclosed in Patent Document 1 below, an eccentric oscillating gear having a configuration in which a drive shaft driven by a motor and an input shaft for driving a crankshaft are connected via a bevel gear mechanism. The device is known. Specifically, as shown in FIG. 3, the gear device disclosed in this document is driven via a transmission gear 104 to a drive shaft 101 driven by a motor and a crankshaft 102 of an eccentric oscillating speed reduction mechanism. And an input shaft 103 for transmitting force. One end of the drive shaft 101 is configured as a drive-side bevel gear 105, and one end of the input shaft 103 is configured as a driven-side bevel gear 106 that meshes with the drive-side bevel gear 105. By interposing a bevel gear mechanism, it can be converted into a direction perpendicular to the direction of input rotation and output.

  The crankshaft 102 and the input shaft 103 are arranged in parallel to each other, and the crankshaft 102 and the input shaft 103 are rotatable to the base casing via bearings 110 and 111 at two locations in the axial direction, respectively. It is supported. The base casing has a configuration in which the base 113 and the end plate 114 are fastened with the external gear 112 of the eccentric oscillating speed reduction mechanism being sandwiched, and the bearings are disposed on the base 113 and the end plate 114, respectively. In the base 113, the bearing 110 of the crankshaft 102 and the bearing 111 of the input shaft 103 are arranged adjacent to each other in the radial direction, and the bearing 110 and the input shaft 103 of the crankshaft 102 are similarly arranged in the end plate 114. The bearings 111 are arranged adjacent to each other in the radial direction.

  Since the input shaft 103 receives a driving force from the driving side bevel gear 105, a thrust load is applied to the bearing 111 of the input shaft 103. For this reason, the bearing 111 of the input shaft 103 is an angular contact radial bearing (conical roller bearing). In addition, the two bearings 111 of the input shaft 103 arranged at an interval in the axial direction have the tapered rollers inclined in opposite directions so that they can receive loads in either direction in the axial direction. ing. Similarly, the two bearings 110 of the crankshaft 102 are also angular contact radial bearings (conical roller bearings), and the inclined directions of the tapered rollers are opposite to each other.

Such an eccentric oscillating gear device can rotate the base 113 around an axis orthogonal to the drive shaft 101, and is used, for example, as a joint mechanism of a robot or the like.
JP 2003-205486 A

  In the eccentric oscillating gear device disclosed in Patent Document 1, the bearing 111 that supports the input shaft 103 and the bearing 110 that supports the crankshaft 102 are disposed adjacent to each other in the radial direction. The size of the bearing 111 that supports the crankshaft is restricted by the bearing 110 that supports the crankshaft 102. For this reason, when the shaft diameter is increased in order to increase the allowable stress of the input shaft 103, it is necessary to reduce the radial thickness of the bearing 111 that supports the input shaft 103. However, in consideration of receiving a thrust load, it is necessary to use an angular contact radial bearing such as a tapered roller bearing, and there is a limit to reducing the radial thickness of the bearing.

  Accordingly, an object of the present invention is to increase the shaft diameter of an input shaft while suppressing an increase in the radial dimension of a member supporting the input shaft in an eccentric oscillating gear device having an input shaft that receives a thrust load. There is.

  In order to achieve the above object, the present invention provides an outer cylinder having internal teeth, an input shaft having a base shaft portion and a tip shaft portion having a smaller diameter than the base shaft portion, and the base shaft portion side of the input shaft. A bevel gear provided at an end, an eccentric part, a crankshaft arranged in parallel with the input shaft and interlocked with the rotation of the input shaft, and attached to the eccentric part and meshing with the internal teeth An external gear that rotates while rotating, a base side portion that is disposed on the bevel gear side with respect to the external gear, and a front side portion that is disposed on the opposite side of the bevel gear with respect to the external gear. A carrier that is rotatably supported by the outer cylinder and through which the input shaft and the crankshaft penetrate, a first crank bearing that rotatably supports the crankshaft with respect to the base side portion, and A second clan that rotatably supports the crankshaft with respect to the front side portion A first bearing that comprises a bearing and a radial contact bearing, and that rotatably supports the base shaft portion of the input shaft with respect to the base side portion of the carrier; and an angular contact radial bearing, the front side of the carrier A second bearing that rotatably supports the front shaft portion of the input shaft with respect to a portion, and an angular contact radial bearing in which an inclination direction for receiving a load is opposite to the second bearing. And a third bearing disposed on the opposite side of the first bearing and rotatably supporting the front shaft portion of the input shaft with respect to the front side portion of the carrier. This is an oscillating gear device.

  In the present invention, a bevel gear is provided at an end of the input shaft on the base shaft portion side, and a driving force is input to the bevel gear. With this driving force, the input shaft rotates and the crankshaft rotates. Then, when the external gear rotates while meshing with the internal teeth of the outer cylinder, the carrier rotates relative to the outer cylinder. At this time, the axial load applied to the input shaft is borne by the second bearing and the third bearing, and the radial load applied to the input shaft is shared by the first to third bearings. Since the load in the axial direction applied to the input shaft is borne by the second and third bearings, the first bearing on the bevel gear side can be a radial contact bearing, and the first bearing is a second contact made of an angular contact radial bearing. And it is possible to easily select a thin shape as compared with the third bearing. For this reason, the shaft diameter of the input shaft is equal to the shaft diameter at the base shaft portion supported by the first bearing closer to the bevel gear than the second and third bearings at the front shaft portion supported by the second and third bearings. Even if it is larger than the shaft diameter, it can be made difficult to be restricted by the crank bearing, and the arrangement space of the first crank bearing can be secured without increasing the outer diameter of the carrier. Therefore, on the side close to the bevel gear, the shaft diameter can be increased while suppressing the increase in the radial dimension of the member supporting the input shaft, and the load resistance can be improved. The first bearing can have a smaller radial thickness by using a roller bearing using cylindrical rollers or needle rollers.

  Here, the external gear is formed with a through hole through which the input shaft is inserted, and at least a part of the second bearing is disposed in the through hole together with the input shaft. preferable. In this aspect, the length of the input shaft can be shortened compared to a configuration in which the second bearing is disposed on the outer side in the axial direction with respect to the external gear. Therefore, it can suppress that the dimension of the axial direction of a gear apparatus expands.

  Further, it is preferable that the second bearing and the third bearing are arranged so that the back surfaces of the outer rings contacting the front side portion of the carrier are close to each other. In this aspect, it is possible to suppress an increase in the axial length of the input shaft in the front side portion of the carrier that supports the second bearing and the third bearing. For this reason, it can suppress that the dimension of the axial direction of a gear apparatus expands.

  Moreover, it is preferable that a preload adjusting means for the second bearing and the third bearing is provided at an end of the input shaft on the side of the front shaft. In this aspect, the preload of the second bearing and the third bearing disposed near the other end of the input shaft can be adjusted.

  As described above, according to the present invention, in the eccentric oscillating gear device having the input shaft that receives the thrust load, the shaft diameter of the input shaft is suppressed while suppressing the increase in the radial dimension of the member that supports the input shaft. Can be expanded.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, an eccentric oscillating gear device 10 according to the present embodiment includes an outer cylinder 12, a carrier 14 that can rotate relative to the outer cylinder 12 inside the outer cylinder 12, and An input shaft 16 for applying a driving force for rotating the carrier 14 and a speed reduction mechanism 18 for rotating the carrier 14 at a rotational speed reduced at a predetermined ratio with respect to the rotational speed of the input shaft 16 are provided. .

  The outer cylinder 12 is formed in a cylindrical shape, and a flange portion 12a is integrally provided on the outer peripheral portion thereof. Bolt insertion holes 12b are provided in the flange portion 12a at equal intervals in the circumferential direction. Bolts 22 for fastening the outer cylinder 12 and the casing 20 are inserted through the bolt insertion holes 12b. The outer cylinder 12 has pin-shaped inner teeth 24 arranged on the inner circumferential surface thereof at regular intervals in the circumferential direction.

  The carrier 14 is supported on the outer cylinder 12 by a pair of main bearings 26 arranged at intervals in the axial direction, and can rotate coaxially with the outer cylinder 12. The main bearings 26 are each constituted by an angular ball bearing.

  The carrier 14 includes an end plate 30 that is a base side portion, and a base portion 31 that is fastened to the end plate 30. The base portion 31 includes a disc-shaped substrate portion 32 that is a front side portion, and a shaft portion 33 that protrudes from one surface of the substrate portion 32. As shown in FIG. 2, the shaft portion 33 has a substantially trapezoidal cross section. In the present embodiment, three shaft portions 33 are provided, and these are arranged at equal intervals in the circumferential direction. The base 31 and the end plate 30 are fastened to each other by a bolt 34 in a state where the tip surface of the shaft portion 33 is in contact with the end plate 30. In this state, a space S having a predetermined width in the axial direction is formed between the substrate portion 32 and the end plate 30. A bolt fastening hole 31a is provided across the shaft portion 33 and the substrate portion 32, and the bolt 34 is screwed into the fastening hole 31a.

  A cover portion 35 is attached to the substrate portion 32. Since the cover part 35 is fastened to the board part 32 with bolts 36, it can be removed from the board part 32. The bolt 36 is screwed into the bolt fastening hole 31a.

  In this embodiment, the base side portion is formed by the end plate 30 and the front side portion is formed by the substrate portion 32. Instead, the base side portion is formed by the substrate portion 32, and the tip portion is formed. The side portion may be formed by the end plate 30. In this case, the cover part 35 is fastened to the end plate 30.

  In the end plate 30 and the substrate portion 32, central through holes 30a and 32a penetrating in the axial direction are formed at the centers. The central through holes 30a and 32a are through holes through which the input shaft 16 is inserted. The input shaft 16 is inserted through the central through holes 30 a and 32 a and is arranged coaxially with the outer cylinder 12.

  The input shaft 16 has a length that can be inserted into the central through holes 30a and 32a of both the end plate 30 and the substrate portion 32, and a step portion 16a is formed in the intermediate portion. The step portion 16a has a step surface perpendicular to the axial direction. A bevel gear 40 is provided at one end 16 b of the input shaft 16. The shaft diameter of the tip shaft portion 16e located on the other end portion 16c side where the bevel gear 40 is not provided with respect to the step portion 16a is equal to that of the base shaft portion 16d located on the one end portion 16b side with respect to the step portion 16a. It is formed smaller than the shaft diameter.

  A drive gear 42 made of an external gear is integrally provided at a portion of the input shaft 16 that protrudes to the outside of the end plate 30, and the bevel gear 40 has an end ahead of the drive gear 42 in the input shaft 16. It is fixed to the part 16b. The bevel gear 40 of the input shaft 16 meshes with the bevel gear 45 of the drive shaft 44. The drive shaft 44 transmits a driving force of a motor (not shown), and the input shaft 16 rotates around an axis perpendicular to the drive shaft 44. Similarly, the rotation axis of the carrier 14 is orthogonal to the drive shaft 44.

  The other end portion 16 c of the input shaft 16 protrudes outward in the axial direction from the end surface 32 b of the substrate portion 32, and is inserted into the central hole 35 a of the cover portion 35. The other end portion 16 c of the input shaft 16 is exposed by removing the cover portion 35.

  The speed reduction mechanism 18 includes a transmission gear 48, a crankshaft 49, and an external gear 50. The transmission gear 48 is fixed to one end portion 16 b of the crankshaft 49 and meshes with a drive gear 42 provided on the input shaft 16. Accordingly, the driving force is transmitted to the crankshaft 49 via the transmission gear 48, whereby the crankshaft 49 is interlocked with the rotation of the input shaft 16.

  The crankshaft 49 is disposed in parallel with the input shaft 16 and has two eccentric portions 49a. The two eccentric parts 49a are arranged adjacent to each other in the axial direction, and they are out of phase with each other. Through holes 30b and 32d are formed in the end plate 30 and the substrate portion 32, and the crankshaft 49 passes through the through holes 30b and 32d. In the present embodiment, three crankshafts 49 are arranged at equal intervals in the circumferential direction.

  Two external gears 50 are provided. Each external gear 50 has a first through hole 50a through which the input shaft 16 can pass, a second through hole 50b through which the shaft portion 33 can pass, and a crank. A third through hole 50c is formed through which the eccentric portion 49a of the shaft 49 can pass. The external gears 50 are respectively attached to the eccentric portions 49a via cylindrical roller bearings, and are arranged in the axial direction. Both external gears 50 are disposed in a space S between the substrate portion 32 and the end plate 30 of the carrier 14. In other words, the end plate 30 of the carrier 14 is disposed on the side of the bevel gear 40 with respect to the external gear 50, and the substrate portion 32 is disposed on the side opposite to the bevel gear 40 with respect to the external gear 50. . The external gear 50 rotates while meshing with the internal teeth 24 of the outer cylinder 12 as the eccentric portion 49 a swings due to the rotation of the crankshaft 49.

  The crankshaft 49 is rotatably supported by the end plate 30 via the first crank bearing 53 and is also rotatably supported by the substrate portion 32 via the second crank bearing 54. In other words, the first crank bearing 53 is disposed between the end plate 30 and the crankshaft 49, and the second crank bearing 54 is disposed between the base plate portion 32 and the crankshaft 49. Both the first crank bearing 53 and the second crank bearing 54 are constituted by tapered roller bearings, and these are arranged in a face-to-face arrangement.

  The input shaft 16 is rotatably supported on the carrier 14 by a first bearing 56, a second bearing 57, and a third bearing 58. The first to third bearings 56 to 58 are arranged in this order from the one end 16 b side of the input shaft 16. The first bearing 56 is configured by a cylindrical roller bearing that is a radial contact bearing, and is disposed between the end plate 30 and the base shaft portion 16 d of the input shaft 16. The first bearing 56 supports the base shaft portion 16 d of the input shaft 16 at a position between the drive gear 42 and the external gear 50.

  The second bearing 57 is configured by a tapered roller bearing that is an angular contact radial bearing, and is disposed between the base plate portion 32 and the front shaft portion 16 e of the input shaft 16. The third bearing 58 is also constituted by a tapered roller bearing that is an angular contact radial bearing, and is disposed between the base plate portion 32 and the front shaft portion 16 e of the input shaft 16. The third bearing 58 is disposed on the opposite side to the first bearing 56 with respect to the second bearing 57, and the third bearing 58 has an inclination direction that receives a load in a direction opposite to that of the second bearing 57. It has become.

  The second bearing 57 and the third bearing 58 support the front shaft portion 16 e of the input shaft 16. And since the 2nd bearing 57 and the 3rd bearing 58 which are located in a line in the axial direction are in a back-to-back arrangement relationship, the outer rings are arranged so as to be closer to each other than the inner rings. The outer ring of the second bearing 57 abuts against a retaining ring 60 fixed to the board portion 32 at the end face on the third bearing 58 side, and protrudes from the end face 32c of the board portion 32 to the external gear 50 side. The inner ring of the second bearing 57 is in contact with the stepped portion 16 a of the input shaft 16 on the end surface opposite to the third bearing 58. Since the step portion 16a is located in the first through hole 50a of the external gear 50 on the other end portion 16c side, a part of the second bearing 57 is connected to the external gear 50 on the other end portion 16c side. It is located in the first through hole 50a.

  The outer ring of the third bearing 58 abuts on a retaining ring 61 fixed to the substrate portion 32 at the end surface on the second bearing 57 side, while the opposite end surface protrudes from the end surface 32b of the substrate portion 32 to the cover portion 35 side. A part of the outer ring enters the central hole 35 a of the cover portion 35. The inner ring of the third bearing 58 slightly protrudes from the end face of the other end portion 16 c of the input shaft 16, and a part of the inner ring enters the central hole 35 a of the cover portion 35.

  The other end portion 16 c of the input shaft 16 is provided with a preload adjusting means 65 for the third bearing 58. The preload adjusting means 65 includes a flat pressing plate 65a having an outer diameter larger than the end surface of the front shaft portion 16e of the input shaft 16, and a bolt 65b for pressing the pressing plate 65a. Since the push plate 65a only needs to press the inner ring of the third bearing 58, the outer diameter of the push plate 65a is smaller than the outer diameter of the inner ring. A bolt hole is provided in the end surface of the front shaft portion 16e, and the preload to the third bearing 58 is adjusted by screwing the bolt 65b inserted into the insertion hole of the push plate 65a into the bolt hole. be able to. Since the head portion of the bolt 65b is disposed in the central hole 35a of the cover portion 35, the preload adjustment can be performed at any time by removing the cover portion 35.

  Here, the operation of the eccentric oscillating gear device according to the present embodiment will be briefly described. In this gear device, the driving force of the motor is transmitted to the input shaft 16 via the driving shaft 44, and the input shaft 16 rotates by receiving this driving force. Since the transmission gear 48 is rotated by the rotation of the input shaft 16, the crankshaft 49 is also rotated integrally. When the crankshaft 49 rotates, the external gear 50 rotates while meshing with the internal teeth 24 as the eccentric portion 49a swings, and has the shaft portion 33 that passes through the second through hole 50b of the external gear 50. The carrier 14 rotates together. The rotational speed of the carrier 14 is a rotational speed that is decelerated at a predetermined ratio with respect to the rotational speed input to the input shaft 16.

  As described above, in the present embodiment, the bevel gear 40 is provided at the one end portion 16b of the input shaft 16, and when the driving force is input to the bevel gear 40, the input shaft 16 is rotated by the driving force. At the same time, the crankshaft 49 rotates. The carrier 14 rotates as the external gear 50 rotates while meshing with the internal teeth 24 of the outer cylinder 12. At this time, the axial load applied to the input shaft 16 is borne by the second bearing 57 and the third bearing 58, and the radial loads applied to the input shaft 16 are the first bearing 56 to the third bearing 58. Shared by. Since the axial load applied to the input shaft 16 is borne by the second and third bearings 57 and 58, the first bearing 56 on the side of the bevel gear 40 can be a cylindrical roller bearing. It becomes thinner than the 2nd and 3rd bearings 57 and 58 which consist of roller bearings. For this reason, the shaft diameter of the input shaft 16 is the tip shaft supported by the second and third bearings 57 and 58 in the base shaft portion 16d closer to the bevel gear 40 than the second and third bearings 57 and 58. Even if it is larger than the shaft diameter at the portion 16e, it can be made difficult to be restricted by the first crank bearing 53, and the arrangement space for the crank bearing 53 can be secured without increasing the outer diameter of the carrier 14. . Accordingly, the input shaft 16 is close to the bevel gear 40, and the shaft diameter can be increased while suppressing the increase in the radial dimension of the member that supports the input shaft 16, and the load resistance can be improved. .

  In the present embodiment, a part of the second bearing 57 is configured to enter the through hole 50 a of the external gear 50, so that the second bearing 57 is positioned outward in the axial direction with respect to the external gear 50. The length of the input shaft 16 can be shortened as compared with the arrangement. Therefore, it can suppress that the dimension of the axial direction of the gear apparatus 10 expands.

  Further, in the present embodiment, the second bearing 57 and the third bearing 58 are arranged in a back-to-back arrangement. Therefore, in the substrate portion 32 of the carrier 14 that supports the second bearing 57 and the third bearing 58, the input shaft 16 An increase in the axial thickness can be suppressed. For this reason, it can suppress that the dimension of the axial direction of the gear apparatus 10 expands.

  In the present embodiment, since the preload adjusting means 65 for the third bearing 58 is provided, the preload for the third bearing 58 can be adjusted. In particular, in the present embodiment, the second bearing 57 and the third bearing 58 are arranged in a back-to-back arrangement. In the third bearing 58, the inner ring protrudes outward in the axial direction from the outer ring. . For this reason, the size of the push plate 65a can be reduced.

  In the present embodiment, the bolts 65b of the preload adjusting means 65 can be exposed by removing the cover portion 35 from the substrate portion 32. Therefore, the preload adjustment of the second bearing 57 and the third bearing 58 is performed even after use. Can be made easier.

  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, in the above-described embodiment, the second bearing 57 and the third bearing 58 are arranged in a back-to-back arrangement, but instead, the second bearing 57 and the third bearing 58 may be arranged in a front-to-face arrangement.

  Moreover, in the said embodiment, although it was set as the structure which a part of 2nd bearing 57 approachs into the 1st through-hole 50a of the external gear 50, it is not restricted to this, The 2nd bearing 57 is an external gear. It is good also as a structure which does not approach in 50 1st through-hole 50a.

  In the above embodiment, the input shaft 16 has the stepped portion 16a and the inner ring of the second bearing 57 contacts the stepped surface of the stepped portion 16a. However, the present invention is not limited to this. For example, in the input shaft 16, the base shaft portion 16d and the front shaft portion 16e having a smaller diameter than the base shaft portion 16d are smoothly connected, and the second bearing 57 is a retaining ring fixed to the front shaft portion 16e of the input shaft 16. It is good also as a structure contact | abutted (illustration omitted).

It is sectional drawing of the eccentric rocking | fluctuation type gear apparatus which concerns on embodiment of this invention. It is a figure when it sees in the arrow direction in the II-II line | wire of FIG. It is sectional drawing of the conventional eccentric rocking | fluctuation type gear apparatus.

Explanation of symbols

12 outer cylinder 14 carrier 16 input shaft 16b one end portion 16c other end portion 16d base shaft portion 16e front shaft portion 24 internal teeth 30 end plate 31 base portion 32 substrate portion 35 cover portion 40 bevel gear 49 crankshaft 49a eccentric portion 50 external gear 50a First through hole 53 First crank bearing 54 Second crank bearing 56 First bearing 57 Second bearing 58 Third bearing 65 Preload adjusting means

Claims (4)

An outer cylinder having internal teeth;
An input shaft having a base shaft portion and a tip shaft portion having a diameter smaller than that of the base shaft portion;
A bevel gear provided at an end of the input shaft on the base shaft side;
A crankshaft having an eccentric portion, arranged in parallel with the input shaft and interlocked with the rotation of the input shaft;
An external gear attached to the eccentric portion and rotating while meshing with the internal teeth;
A base side portion disposed on the bevel gear side with respect to the external gear, and a front side portion disposed on the opposite side of the bevel gear with respect to the external gear, A carrier that is rotatably supported and through which the input shaft and the crankshaft pass;
A first crank bearing that rotatably supports the crankshaft with respect to the base side portion;
A second crank bearing that rotatably supports the crankshaft with respect to the front side portion;
A first bearing comprising a radial contact bearing, and rotatably supporting the base shaft portion of the input shaft with respect to the base side portion of the carrier;
A second bearing comprising an angular contact radial bearing, and rotatably supporting the front shaft portion of the input shaft with respect to the front side portion of the carrier;
An angular contact radial bearing whose load is inclined in a direction opposite to that of the second bearing is disposed on the side opposite to the first bearing with respect to the second bearing, and the front side portion of the carrier. And a third bearing that rotatably supports the front shaft portion of the input shaft. The external gear has a through hole through which the input shaft is inserted,
The eccentric oscillating gear device according to claim 1, wherein at least a part of the second bearing is disposed in the through hole together with the input shaft.   3. The eccentric oscillating gear device according to claim 1, wherein the second bearing and the third bearing are arranged such that back surfaces of the outer rings contacting the front side portion of the carrier are close to each other. .   The eccentric rocking | fluctuation type of any one of Claim 1 to 3 with which the preload adjustment means of the said 2nd bearing and the said 3rd bearing is provided in the edge part by the side of the said front shaft part in the said input shaft. Gear device.

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