JP2014190517A - Eccentric oscillation type gear device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assure a desired distribution of lubricant oil even if a washer restricting an axial movement of an eccentric bearing is arranged.SOLUTION: An eccentric oscillation type gear device of this invention comprises a crank shaft 20 having eccentric segments 20a; an oscillation gear into which the eccentric segments 20a are inserted and cooperated with the eccentric segments 20a through rotation of the crank shaft 20; eccentric segment bearings 28 allowing a relative rotation between the oscillation gear and the eccentric segments 20a to be attained; and washers 30 for restricting an axial movement of the eccentric segment bearings 28. The eccentric segment bearings 28 include a plurality of rollers 42 and a cage 44 for holding the rollers 42. The washers 30 include a narrow width segment 30b with its outer end being positioned at a more inner side in a radial direction than the inner end of the cage 44, and a wide width segment 30c with its outer end being positioned at a more outside in a radial direction than the inner end of the cage 44 and its shape is formed in elliptical shape.

Description

  The present invention relates to an eccentric oscillating gear device.

  Conventionally, as disclosed in Patent Document 1 below, an oscillating gear device that reduces the rotational speed at a predetermined reduction ratio between a pair of mating members is known. This oscillating gear device includes an outer cylinder fixed to one counterpart member and a carrier fixed to the other counterpart member, and the carrier is an oscillating portion attached to an eccentric portion of the crankshaft. The gear rotates relative to the outer cylinder by the swinging rotation of the gear. As shown in FIG. 6, an eccentric portion bearing 63 is attached to the eccentric portion 61 a of the crankshaft 61, and the eccentric portion bearing 63 attached to the eccentric portion 61 a is disposed in the insertion hole of the swing gear 64. Has been. The eccentric part bearing 63 has a large number of cylindrical rolling elements 63a and a cage 63b that holds the rolling elements 63a. A washer 65 is fitted to the crankshaft 61 so as to sandwich the two eccentric portions 61a. Thereby, the eccentric part bearing 63 is restricted from moving in the axial direction. As shown in FIG. 7, a plurality of through holes 65 a are formed in the washer 65 at equal intervals in the circumferential direction. The through hole 65a is formed at a position where it can communicate with the annular gap 67 between both side walls of the cage 63b and the eccentric portion 61a. As a result, the lubricating oil flows into the retainer 63b through the through hole 65a of the washer 65, and the lubricating oil in the retainer 63b flows out. As a result, the lubricating oil in the cage 63b is replaced, and deterioration of the lubricating performance can be prevented.

JP 2006-29393 A

  However, in the eccentric oscillating gear device disclosed in Patent Document 1, the through hole 65a is formed at a position where it can communicate with the annular gap 67 between the both side walls of the cage 63b and the eccentric portion 61a. In reality, however, only a small part of the through-holes 65a communicate with the annular gap 67, and the other through-holes 65a are displaced from the annular gap 67 so that the eccentric portion 61a or the retainer 63b. It is blocked by. For this reason, even if the plurality of through holes 65a are provided, the through holes 65a are not fully utilized, and the desired flowability of the lubricating oil cannot be ensured.

  Therefore, the present invention has been made in view of the above-described prior art, and an object of the present invention is to achieve the desired lubricating oil even when a washer is provided that restricts axial movement of the eccentric bearing. Is to ensure the distribution of

  In order to achieve the above object, the present invention provides a crankshaft having an eccentric portion and an insertion hole into which the eccentric portion is inserted, and swings in conjunction with the eccentric portion by rotation of the crankshaft. A dynamic gear, an eccentric bearing that is disposed in the insertion hole and allows relative rotation between the swing gear and the eccentric part, and a washer that restricts the eccentric part bearing from moving in the axial direction; The eccentric portion bearing includes a plurality of rolling elements and a cage that holds the rolling elements, and the washer has an outer end portion radially inward of an inner end portion of the cage. An eccentric oscillating gear device having a narrow-width portion positioned and a wide-width portion having an outer end portion positioned radially outward from the inner end portion of the cage.

  In the present invention, since the outer end portion of the wide portion of the washer is positioned radially outward from the inner end portion of the cage, the wide portion of the washer is regulated so as not to move in the axial direction. Can do. On the other hand, the outer end portion of the narrow portion of the washer is located radially inward from the inner end portion of the cage. For this reason, the annular clearance between the inner end portion and the eccentric portion of the cage is exposed outside the narrow portion. Accordingly, in the narrow portion, the lubricating oil flows into the annular gap from the outside, and the lubricating oil in the cage flows out through the annular gap located outside the narrow portion. In other words, since the annular gap is always exposed outside the narrow part in a part of the circumferential direction, even if a washer that restricts the axial movement of the eccentric bearing is provided, the desired flow of the lubricating oil is ensured. can do.

  Here, the outer end portion of the narrow width portion may be located radially inward from the outer end portion of the eccentric portion. In this aspect, the entire width of the annular gap between the inner end portion of the cage and the eccentric portion is exposed outside the narrow width portion. Therefore, the flowability of the lubricating oil can be improved as compared with the case where only a part of the annular gap in the width direction is exposed.

  The annular gap between the inner end portion of the cage and the eccentric portion may be continuously exposed over a range where a plurality of rolling elements are disposed. In this aspect, the annular gap is continuously exposed in the circumferential direction in a range where a plurality of rolling elements are arranged. Therefore, the flowability of the lubricating oil can be improved as compared with the case where the annular gap is exposed in a limited range in the circumferential direction or the case where the annular gap is exposed intermittently.

  The narrow portion may be formed on both sides of the inner hole of the washer, and the wide portion may be formed on both sides of the inner hole of the washer. In this case, the direction connecting the narrow portions on both sides and the direction connecting the wide portions on both sides may be orthogonal to each other. In this aspect, since the wide portion is formed on both sides of the inner hole, the cage can be stably held. Moreover, since the direction connecting the narrow portions on both sides and the direction connecting the wide portions on both sides are orthogonal to each other, both the holding stability of the cage and the flowability of the lubricating oil can be achieved.

  The washer may be oval. In this aspect, both the holding stability of the cage and the flowability of the lubricating oil can be achieved.

  As described above, according to the present invention, the desired flowability of the lubricating oil can be ensured even when the washer for restricting the axial movement of the eccentric bearing is provided.

It is sectional drawing which shows the whole structure of the eccentric rocking | fluctuation type gear apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the crankshaft provided in the said eccentric rocking | fluctuation type gear apparatus, and its surrounding structural member. It is sectional drawing in the III-III line of FIG. It is a front view of the washer fitted to the crankshaft. It is a front view of the washer provided in the eccentric rocking | fluctuation type gear apparatus which concerns on other embodiment of this invention. It is sectional drawing which shows the principal part of the conventional eccentric rocking | fluctuation type gear apparatus. It is a figure for demonstrating the eccentric part bearing and washer 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.

  The eccentric oscillating gear device according to the present embodiment is a gear device that is applied as a speed reducer to, for example, a turning portion such as a turning barrel or arm joint of a robot or a turning portion of various machine tools. In the following description of the present embodiment, an example in which an eccentric oscillating gear device (hereinafter simply referred to as a gear device) is applied to a revolving drum of a robot will be described.

  As shown in FIG. 1, this gear device transmits a rotational driving force by decelerating at a predetermined reduction ratio between a base 50 (one counterpart member) and a revolving body 52 (the other counterpart member). . The gear device of the present embodiment includes an outer cylinder 2, an internal tooth pin 3, a carrier 4, a main bearing 6, a crankshaft gear 18, a crankshaft 20, a crank bearing 22, and a swing gear 24. I have.

  The outer cylinder 2 is a first fixing member that can be fixed to one counterpart member, and functions as a case constituting the outer surface of the gear device. The outer cylinder 2 is formed in a substantially cylindrical shape, and is fastened to, for example, the base 50 fixed on the installation surface. On the inner surface of the outer cylinder 2, a large number of internal tooth pins 3 are arranged at equal intervals in the circumferential direction. The internal tooth pin 3 functions as an internal tooth with which a swing gear 24 made of an external gear meshes. The number of teeth of the oscillating gear 24 is slightly smaller than the number of internal tooth pins 3. In the present embodiment, two oscillating gears 24 are used, but the present invention is not limited to this.

  The carrier 4 is a second fixing member that can rotate relative to the first fixing member and can be fixed to the other mating member, and is disposed outside the carrier 4 in a state of being coaxial with the outer cylinder 2. Arranged inside the cylinder 2. The carrier 4 rotates relative to the outer cylinder 2 around the same axis. The carrier 4 is fastened to the revolving body 52, and the revolving body 52 revolves with respect to the base 50 when the carrier 4 rotates relative to the outer cylinder 2.

  The carrier 4 is supported so as to be relatively rotatable with respect to the outer cylinder 2 by a pair of main bearings 6 which are provided apart from each other in the axial direction. The carrier 4 includes a base portion 32 and an end plate portion 34. The base portion 32 and the end plate portion 34 are fastened to each other so as to accommodate the rocking gear 24 therebetween.

  The base portion 32 includes a substrate portion 32 a disposed in the outer cylinder 2 in the vicinity of the end portion of the outer cylinder 2, and a shaft portion 32 b extending in the axial direction from the substrate portion 32 a toward the end plate portion 34. The shaft portion 32b is fastened to the end plate portion 34 by a bolt 5 having a head portion 5a and a male screw portion 5b continuous with an end surface of the head portion 5a. Thereby, the base 32 and the end plate part 34 are integrated.

  A plurality of the crankshafts 20 are provided, and each crankshaft 20 is arranged at equal intervals in the circumferential direction. A crankshaft gear 18 is attached to the end of each crankshaft 20. The crankshaft gear 18 meshes with a drive gear (not shown) driven by a drive source (motor) (not shown). Each crankshaft gear 18 transmits the rotation of the drive gear to the crankshaft 20 to which the crankshaft gear 18 is attached. That is, the crankshaft gear 18 functions as an input unit to which a driving force for rotating the crankshaft 20 is input from a driving source.

  Each crankshaft 20 is attached to the carrier 4 via a pair of crank bearings 22 so as to be rotatable about the axis. That is, the crankshaft 20 is rotatably supported by the carrier 4. The crank bearing 22 is disposed in crankshaft holes 32e and 34c formed through the substrate portion 32a and the end plate portion 34, respectively.

  The crankshaft 20 includes a shaft body 20b and a plurality (two in this embodiment) of eccentric portions 20a formed integrally with the shaft body 20b. The plurality of eccentric portions 20 a are arranged so as to be aligned in the axial direction at a position between the pair of crank bearings 22. The eccentric portions 20a are each formed in a cylindrical shape that is eccentric from the axis of the shaft main body 20b of the crankshaft 20 by a predetermined amount of eccentricity. And each eccentric part 20a is formed in the crankshaft 20 so that it may have a phase difference of a predetermined angle mutually. In this embodiment, it has a phase difference of 180 degrees.

  The oscillating gear 24 is attached to the eccentric portion 20a of the crankshaft 20 via an eccentric portion bearing 28, and is disposed so as to be sandwiched between the substrate portion 32a and the end plate portion 34. The oscillating gear 24 is formed to be slightly smaller than the inner diameter of the outer cylinder 2 and meshes with the internal tooth pin 3 on the inner surface of the outer cylinder 2 in conjunction with the eccentric rotation of the eccentric portion 20a when the crankshaft 20 rotates. Oscillates and rotates.

  The oscillating gear 24 has a plurality of eccentric part insertion holes 24c and a plurality of shaft part insertion holes 24d. In the illustrated example, the oscillating gear 24 having a through hole 24b formed in the center is shown, but the central through hole 24b can be omitted.

  The eccentric portion insertion holes 24 c are provided at equal intervals in the circumferential direction around the central through hole 24 b in the swing gear 24. The eccentric portion 20a of each crankshaft 20 is inserted into each eccentric portion insertion hole 24c with the eccentric portion bearing 28 interposed therebetween.

  Each eccentric portion 20a is fitted with an eccentric portion bearing 28, and a pair of washers 30 and 30 are fitted to the shaft body 20b of the crankshaft 20 so as to sandwich the eccentric portion bearings 28 therebetween. That is, all the eccentric part bearings 28 are sandwiched between the pair of washers 30 and 30. Each washer 30 is sandwiched between the crank bearing 22 and the eccentric portion 20a. Both crank bearings 22 and 22 are fixed by a retaining ring 31 so as not to be displaced with respect to the substrate portion 32 a and the end plate portion 34.

  The shaft portion insertion holes 24 d are provided at equal intervals in the circumferential direction around the central through hole 24 b in the swing gear 24. Each shaft portion insertion hole 24d is disposed at a position between the eccentric portion insertion holes 24c in the circumferential direction. In each shaft portion insertion hole 24d, the shaft portion 32b is inserted in a state where a gap is left between the shaft portion 32b and the outer peripheral surface of the shaft portion 32b of the carrier 4.

  As shown in FIG. 2, the eccentric portion bearing 28 is constituted by a radial roller bearing having a plurality of rolling elements 42 and a cage 44 that holds the rolling elements 42. The roller bearing may be a cylindrical roller bearing having a relatively large diameter of the rolling element 42 or a needle roller bearing having a relatively small diameter of the rolling element 42.

  The retainer 44 is provided with a pair of side walls 44a, 44a and a plurality of connecting portions 44b, 44b,... That connect the pair of side walls 44a, 44a.

  Each of the rolling elements 42 is formed in a cylindrical shape, and is held at equal intervals in the circumferential direction by a cage 44.

  The pair of side walls 44a, 44a are arranged at intervals in the axial direction of the rolling element 42 and are parallel to each other. The inner surface of each side wall 44 a faces the end surface of the rolling element 42. Each side wall 44a is formed in an annular flat plate shape, and its radial width is slightly smaller than the diameter of the rolling element 42 (see FIG. 3). For this reason, when the eccentric part bearing 28 is fitted on the eccentric part 20a, a gap (annular gap) having a predetermined width is formed between the inner end of each side wall 44a of the cage 44 and the outer peripheral surface of the eccentric part 20a. 46 is made. The annular gap 46 is formed over the entire outer peripheral surface of the eccentric portion 20a.

  A washer 30 is adjacent to each eccentric part 20a. The washers 30 are respectively arranged on the outer sides in the axial direction of the eccentric parts 20a so as to sandwich the eccentric parts 20a.

  As shown in FIGS. 3 and 4, the washer 30 has an elliptical outer shape in which an inner hole 30 a is formed through the central portion. That is, the washer 30 has a pair of narrow portions 30b and a pair of wide portions 30c.

  The narrow width portion 30b is a portion where the outer end portion is located radially inside the outer end portion of the eccentric portion 20a. Therefore, a gap 48 is formed between the narrow portion 30 b of the washer 30 and the side wall 44 a of the cage 44. Therefore, the outer end portion of the narrow width portion 30 b is located on the radially inner side with respect to the inner end portion of the side wall 44 a of the cage 44. The gap 48 is continuous between the narrow width portion 30b and the side wall 44a of the retainer 44 (the outer peripheral surface of the eccentric portion 20a) over a range where the plurality of rolling elements 42 are disposed. That is, the gap 48 has a length including a range in which the plurality of rolling elements 42 are arranged in the circumferential direction of the cage 44. For this reason, the lubricating oil easily enters between the adjacent rolling elements 42 and 42 through the gap 48.

  The wide width portion 30 c is a portion where the outer end portion is located on the radially outer side than the inner end portion of the side wall 44 a of the cage 44. Therefore, as shown in FIG. 2, the washer 30 is in axial contact with the side wall 44a of the retainer 44 in the wide width portion 30c.

  The narrow portion 30b is formed on both sides of the inner hole 30a through which the shaft main body 20b is inserted as seen in the axial direction (see FIGS. 3 and 4). Therefore, the width of the washer 30 in the direction connecting the pair of narrow portions 30b is smaller than the outer diameter of the eccentric portion 20a.

  The wide portion 30c is formed on both sides of the inner hole 30a through which the shaft main body 20b is inserted as viewed in the axial direction. Therefore, the width of the washer 30 in the direction connecting the pair of wide portions 30 c is larger than the inner diameter of the side wall 44 a of the cage 44.

  The narrow portions 30b and the wide portions 30c are alternately positioned in the circumferential direction, and the direction D1 connecting the narrow portions 30b on both sides and the direction D2 connecting the wide portions 30c on both sides are orthogonal to each other. . For this reason, even in the configuration in which the retainer 44 is retained by the washer 30 so as not to move in the axial direction, oil permeability is ensured.

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

  When each crankshaft gear 18 receives a rotational driving force from a driving source (not shown), each crankshaft gear 18 rotates around its axis to rotate each crankshaft 20. As a result, the eccentric portions 20a, 20a of the crankshaft 20 are rotated eccentrically, and the swing gears 24, 24 are interlocked with the eccentric rotation of the eccentric portions 20a, 20a so Oscillates while meshing with. The swing rotation of the swing gear 24 is transmitted to the carrier 4 through each crankshaft 20. As a result, the carrier 4 and the revolving structure 52 rotate relative to the outer cylinder 2 and the base 50 at a rotational speed decelerated from the input rotation. The crankshaft 20 can rotate forward and backward, and the rotation direction of the carrier 4 is determined according to which direction the crankshaft 20 rotates. Lubricating oil is sealed in the space between the base plate portion 32a and the end plate portion 34, so that the crankshaft 20 rotates when the turning cylinder of the robot changes its posture (the direction of the gear device changes) or Occasionally, the lubricating oil flows back and forth inside the cage 44. At this time, part of the lubricating oil flows into the retainer 44 through the gap 48 and the annular gap 46 between the washer 30 and the side wall 44 a of the retainer 44, and flows out from the retainer 44.

  As described above, in the present embodiment, since the outer end portion of the wide portion 30c of the washer 30 is located radially outside the inner end portion of the retainer 44, the washer 30 is held by the wide portion 30c of the washer 30. The device 44 can be restricted from moving in the axial direction. On the other hand, the outer end portion of the narrow portion 30 b of the washer 30 is located on the radially inner side of the inner end portion of the cage 44. For this reason, a part of the circumferential direction of the annular gap 46 between the inner end portion of the cage 44 and the eccentric portion 20a is exposed outside the narrow width portion 30b. Therefore, in the narrow width portion 30b, the lubricating oil flows into the annular gap 46 from the outside, and the lubricating oil in the cage 44 flows out through the outside of the narrow width portion 30b. That is, since the annular gap 46 is necessarily exposed outside the narrow portion 30b in a part in the circumferential direction, even if the washer 30 for restricting the axial movement of the eccentric portion bearing 28 is provided, the desired lubricant oil is provided. Distribution can be ensured.

  Moreover, in the present embodiment, the outer end portion of the narrow portion 30b is positioned radially inward from the outer end portion of the eccentric portion 20a, so that the outer end portion of the cage 44 and the outer end portion of the narrow portion 30b The entire width of the annular gap 46 between the eccentric part 20a is exposed. Therefore, the flowability of the lubricating oil can be improved as compared with the case where only a part of the annular gap 46 in the width direction is exposed.

  In the present embodiment, the annular gap 46 is continuously exposed in the circumferential direction in a range where the plurality of rolling elements 42 are arranged. Therefore, the flowability of the lubricating oil can be improved as compared with the case where the annular gap 46 is exposed in a limited range in the circumferential direction or the case where it is exposed intermittently.

  Moreover, in this embodiment, since the wide part 30c is each formed in both sides on both sides of the inner hole 30a, the holder | retainer 44 can be hold | maintained stably. Moreover, since the direction D1 connecting the narrow portions 30b on both sides and the direction D2 connecting the wide portions 30c on both sides are orthogonal to each other, both the holding stability of the cage 44 and the flowability of the lubricating oil are compatible. be able to.

  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 two eccentric portions 20a are provided on the crankshaft 20, and the two washers 30 and 30 are provided so as to sandwich the eccentric portions 20a and 20a. However, the present invention is not limited to this. . The structure in which three or more eccentric parts 20a are provided may be sufficient. Moreover, the structure by which only one eccentric part 20a is provided may be sufficient. In this case, washers 30 are provided on both axial sides of one eccentric portion 20a.

  In the above embodiment, the washer 30 is sandwiched between the eccentric portion 20a and the crank bearing 22. However, the present invention is not limited to this. For example, the washer 30 may be sandwiched between the eccentric portion 20a and a retaining ring (not shown).

  Moreover, in the said embodiment, although the washer 30 was set as the structure which has an elliptical external shape, it is not restricted to this. For example, as shown in FIG. 5, it may be formed in a polygonal shape elongated in one direction. In the illustrated example, it is formed in an octagonal shape, but may be formed in a hexagonal shape. In the form shown in FIG. 5 as well, the washer 30 has a pair of narrow portions 30b and a pair of wide portions 30c. When viewed in the axial direction, the narrow portion 30b is formed on both sides of the inner hole 30a through which the shaft body 20b is inserted, and the wide portion 30c is formed on both sides of the inner hole 30a. .

  In the above embodiment, the plurality of crankshafts 20 are arranged around the central through hole formed in the central portion of the carrier 4. However, the present invention is not limited to this. For example, the crankshaft 20 may be a center crank type in which the crankshaft 20 is disposed in the central through hole of the carrier 4.

2 Outer cylinder 3 Internal tooth pin 4 Carrier 6 Main bearing 20 Crankshaft 20a Eccentric part 20b Shaft body 22 Crank bearing 24 Oscillating gear 24c Eccentric part insertion hole 28 Eccentric part bearing 30 Washer 30a Inner hole 30b Narrow part 30c Wide part 32 Base part 32a Substrate part 32b Shaft part 34 End plate part 42 Rolling element 44 Cage 44a Side wall 46 Annular gap 48 Gap

Claims (5)

A crankshaft having an eccentric portion;
An oscillating gear that is formed with an insertion hole into which the eccentric part is inserted, and oscillates in conjunction with the eccentric part by rotation of the crankshaft,
An eccentric bearing disposed in the insertion hole and allowing relative rotation between the swing gear and the eccentric part;
A washer for restricting movement of the eccentric part bearing in the axial direction,
The eccentric part bearing has a plurality of rolling elements, and a cage that holds the rolling elements,
The washer includes a narrow width portion having an outer end portion positioned radially inward of the inner end portion of the cage, and a wide width portion having an outer end portion positioned radially outward of the inner end portion of the cage. And an eccentric oscillating gear device.   2. The eccentric oscillating gear device according to claim 1, wherein an outer end portion of the narrow width portion is located radially inward from an outer end portion of the eccentric portion.   The eccentric rocking | fluctuation type | mold of Claim 1 or 2 with which the annular clearance between the inner end part of the said holder | retainer and the said eccentric part is continuously exposed over the range in which the several rolling element is arrange | positioned. Gear device. The narrow portion is formed on both sides of the inner hole of the washer,
The wide portion is formed on both sides of the inner hole of the washer,
The eccentric oscillating gear device according to any one of claims 1 to 3, wherein a direction connecting the narrow portions on both sides and a direction connecting the wide portions on both sides are orthogonal to each other.   The eccentric oscillating gear device according to any one of claims 1 to 4, wherein the washer has an elliptical shape.

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