JP5973236B2 - Eccentric oscillating gear unit - Google Patents

Description

  The present invention relates to an eccentric oscillating gear device.

  Conventionally, as disclosed in Patent Documents 1 and 2 below, there is known an oscillating gear device that decelerates the rotational speed at a predetermined reduction ratio between a pair of counterpart members. 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 attached to an eccentric portion of the crankshaft. It rotates relative to the outer cylinder by the swinging rotation of the swinging gear. An eccentric part bearing is attached to the eccentric part of the crankshaft, and an insertion hole into which the eccentric part bearing attached to the eccentric part is inserted is formed in the swing gear. The eccentric portion bearing is configured to hold a cylindrical rolling element by a cage. Many cages have a U-shaped or M-shaped cross-sectional shape to prevent deformation, wear, and breakage. By setting it as such a structure, the intensity | strength of a holder | retainer can be ensured and the movement of a rolling element can be controlled. In addition, the structure which controls that a cylindrical rolling element moves to an axial direction with a washer is also known as disclosed by the following patent document 3.

JP 2010-230171 A JP 2009-047294 A JP 2008-202664 A

  The configurations disclosed in Patent Documents 1 to 3 have a problem that the oil permeability of the lubricating oil is deteriorated because the rolling surface of the rolling element and the end surface in the axial direction are covered.

  Then, this invention is made | formed in view of the said prior art, The place made into the objective is to improve the distribution | circulation property of lubricating oil by devising the structure of the holder in an eccentric part bearing. .

In order to achieve the above object, the present invention includes a crankshaft having an eccentric portion, an input portion to which a driving force for rotating the crankshaft is input, and an insertion hole into which the eccentric portion is inserted, An oscillating gear that oscillates in conjunction with the eccentric portion by rotation of a crankshaft, and an eccentric portion bearing that is disposed in the insertion hole and allows relative rotation between the oscillating gear and the eccentric portion. The eccentric part bearing includes a plurality of cylindrical rolling elements and a cage for holding the rolling element, and the cage is formed in an annular shape surrounding the eccentric part and the rolling element. A pair of side walls arranged at intervals in the axial direction of the moving body, a plurality of connecting portions that are positioned between adjacent rolling elements and connect the pair of side walls, and the connecting portions are connected to each side wall. Sectional shape recessed from the outer peripheral edge of the side wall Said to extend in the longitudinal direction of the connecting portion and the cutout portion formed across each connecting portion from each side wall, it is provided, wherein the notch is shallower than the radial thickness of the side wall and having The eccentric oscillating gear device is formed so as to extend from the outer peripheral surface to the inner peripheral surface of the connecting portion while having a radial depth .

  In the present invention, in the cage that holds the rolling element of the eccentric part bearing, a notch having a cross-sectional shape recessed from the outer peripheral edge of the side wall is formed, and the notch extends in the longitudinal direction of the connecting part. Formed in each connecting portion. For this reason, when the crankshaft rotates while at least a part of the crankshaft is immersed in the lubricating oil, and the swinging gear swings, the oil flows through the notch portion of the cage. For this reason, the flow of oil from the outside of the cage into the cage and the flow of oil from the inside of the cage to the outside of the cage are likely to occur. Therefore, it is possible to easily distribute the oil when the crankshaft rotates forward and backward. In addition, since the notch has a cross-sectional shape that is recessed from the outer peripheral edge of the side wall, a washer is provided when the gap between the insertion hole formed in the rocking gear and the cage is small or adjacent to the side wall. Even in such a case, it is possible to ensure the oil permeability of the lubricating oil to the rolling surfaces and end surfaces of the rolling elements.

  Here, the said notch part may be formed in the diagonal position in each connection part. In this aspect, the rolling elements can be held in a balanced manner. Further, since the lubricating oil is directly supplied to the rolling surface of the rolling element, it is possible to effectively prevent wear or breakage due to poor lubrication.

On the other hand, the said notch part may be formed so that the outer peripheral surface and inner peripheral surface of the said connection part may be penetrated in the center of the width direction of each connection part. In this aspect, it is possible to ensure the inflow of the lubricating oil into the cage by the notch while maintaining the configuration in which the entire length of the connecting portion is in contact with the rolling surface of the rolling element.
You may further provide the washer arrange | positioned at the side of the said eccentric part bearing. In this case, the cutout portion may have a shape that is not blocked by the washer even in a portion where the projecting width of the crankshaft from the shaft main body is the smallest in the eccentric portion.

  As described above, according to the present invention, the flowability of the lubricating oil in the cage of the eccentric part bearing can be improved.

It is sectional drawing which shows the structure of the eccentric rocking | fluctuation type gear apparatus which concerns on embodiment of this invention. It is a perspective view of the eccentric part bearing provided in the said eccentric rocking | fluctuation type gear apparatus. (A) It is a front view of the holder | retainer which comprises the said eccentric part bearing, (b) It is sectional drawing in the IIIb-IIIb line | wire of (a). It is a figure for demonstrating the connection part and notch part of the said holder | retainer. It is a perspective view of the holder | retainer provided in the eccentric rocking | fluctuation type gear apparatus which concerns on other embodiment of this invention. It is a perspective view of the holder | retainer provided in the eccentric rocking | fluctuation type gear apparatus which concerns on other embodiment of this invention. It is a perspective view of the holder | retainer provided in the eccentric rocking | fluctuation type gear apparatus which concerns on other embodiment of this invention. It is a perspective view of the holder | retainer provided in the eccentric rocking | fluctuation type gear apparatus which concerns on other embodiment of this invention.

  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 force by decelerating at a predetermined reduction ratio between a base 50 (one mating member) and a revolving body 52 (the other mating 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. And.

  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 is rotatable relative to the first fixing member, and is disposed inside the outer cylinder 2 in a state of being coaxially disposed with the outer cylinder 2. Yes. 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 that 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. That is, the first coupling hole 34a is formed in the end plate portion 34 so as to penetrate in the thickness direction. The first coupling hole 34a is configured by a stepped hole, and the head 5a of the bolt 5 is disposed in the large diameter portion of the first coupling hole 34a.

  A second coupling hole 32c and a positioning hole 32d are formed on the front end surface of the shaft portion 32b (the contact surface with the end plate portion 34). The second coupling hole 32c is constituted by a screw hole, and the male thread portion 5b of the bolt 5 inserted through the first coupling hole 34a is screwed into the second coupling hole 32c. The base portion 32 and the end plate portion 34 are coupled to each other by the bolt 5. On the other hand, the pin 36 is press-fitted into the positioning hole 32d. By inserting the pin 36 inserted into the pin hole 34b of the end plate portion 34 into the positioning hole 32d, the end plate portion 34 is positioned with respect to the base portion 32.

  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 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.

  An oil supply hole 40 is formed in the crankshaft 20. The oil supply hole 40 includes a main portion 40a extending in the axial direction of the shaft body 20b of the crankshaft 20, a branch portion 40b extending in a radial direction from an intermediate position of the main portion 40a, and opening between the two eccentric portions 20a and 20a. ,have. One end of the main portion 40a opens at one end portion of the shaft body 20b of the crankshaft 20, and the other end of the main portion 40a opens at the other end portion of the shaft body 20b of the crankshaft 20.

  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. 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 FIGS. 2, 3 (a) and 3 (b), 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 these rolling elements 42. Has been. 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 includes a pair of side walls 44a, 44a, a plurality of connecting portions 44b, 44b,... That connect the pair of side walls 44a, 44a, and side walls 44a, 44a to connecting portions 44b, 44b,. Notched portions 44c, 44c,... Formed over are provided.

  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 44 a is formed in an annular flat plate shape, and its radial width is slightly smaller than the diameter of the rolling element 42. For this reason, when the eccentric part bearing 28 is fitted on the eccentric part 20a, the outer end part of the rolling element 42 protrudes radially outward from the side wall 44a. Therefore, a gap having a predetermined width is formed between each side wall 44 a of the cage 44 and the inner peripheral surface of the eccentric portion insertion hole 24 c in the swing gear 24.

  The connecting portions 44b, 44b,... Are arranged along the outer peripheral portion of the side wall 44a at equal intervals in the circumferential direction of the side wall 44a, and each connecting portion 44b extends in a direction orthogonal to the main surface of the side wall 44a. It is formed as follows. Each connecting portion 44b has one end connected to the inner surface of the outer peripheral portion of one side wall 44a, and the other end connected to the inner surface of the outer peripheral portion of the other side wall 44a. That is, each side wall 44a projects radially inward from the connecting portion 44b. For this reason, the retainer 44 has a U-shaped cross section. And the rolling element 42 is arrange | positioned so that a longitudinal direction may become a direction parallel to the longitudinal direction of the connection part 44b.

  The notch 44c is provided to improve the flowability of the lubricating oil between the outer side and the inner side of the retainer 44, and the outer side of the side wall 44a is connected to the side wall 44a where the connecting portion 44b is connected. It has a cross-sectional shape (substantially inverted triangular shape) recessed from the periphery (see FIG. 4). And the notch part 44c is formed ranging from the side wall 44a to each connection part 44b so that it may extend in the longitudinal direction of the connection part 44b. For this reason, the connecting portion 44b has a trapezoidal cross section in which the upper side (outer side) is wider than the lower side (inner side) at the central portion in the longitudinal direction, while the width at both ends in the longitudinal direction. At least a part of the direction end portion (side portion) is formed in a cross-sectional shape that is cut off in an inclined manner.

  A washer 30 is disposed on the side of the eccentric portion bearing 28 attached to the eccentric portion 20a (see FIG. 1), but the notch portion 44c formed in the side wall 44a of the retainer 44 is formed in the eccentric portion 20a. Even when the overhanging width from the shaft body 20b is the smallest, it is not blocked by the washer 30. That is, the notch 44 c is always located on the radially outer side of the washer 30. Therefore, even when the retainer 44 is held by the washer 30 so as not to move in the axial direction, oil permeability through the notches 44c, 44c,... Is ensured.

  In the present embodiment, the notches 44c and 44c are arranged at diagonal positions in the connecting portion 44b. Specifically, the outer surface (radially outer surface) of the connecting portion 44b is formed in a rectangular shape, and the notches 44c and 44c are formed at positions including the corner portions at the diagonal positions among the four corners of the rectangle. Is formed. Therefore, in the end portion connected to one side wall 44a among the end portions of the connecting portion 44b, the notch portion 44c is formed on one end side in the circumferential direction, while the notch portion 44c is formed on the other end side in the circumferential direction. Not formed. Moreover, in the edge part connected with the other side wall 44a among the edge parts of the connection part 44b, the notch part 44c is not formed in the one end side of the circumferential direction, and a notch part is formed in the other end side of the circumferential direction. 44c is formed.

  The range of the length direction in which the notch part 44c is formed among the side surfaces of the connection part 44b is one half or less of the length of the connection part 44b. Of the outer peripheral surface of the rolling element 42, the central portion in the axial direction (the portion where the notches 44c and 44c are not formed) is in contact with the side surfaces of the connecting portions 44b and 44b located on both sides. Thereby, the rolling element 42 located between adjacent connection parts 44b and 44b can be hold | maintained stably.

  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 that the internal teeth pins 3, 3 on the inner surface of the outer cylinder 2 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, a part of the lubricating oil flows into the retainer 44 through the notches 44c, 44c,... And flows out from the retainer 44. Lubricating oil is also supplied between the eccentric portions 20 a through the oil supply holes 40 formed in the crankshaft 20.

  As described above, in this embodiment, the retainer 44 that holds the rolling element 42 of the eccentric portion bearing is formed with the notch 44c having a cross-sectional shape that is recessed from the outer peripheral edge of the side wall 44a. The notch portion 44c is formed in each connecting portion 44b so as to extend in the longitudinal direction of the connecting portion 44b. Therefore, when the crankshaft 20 rotates with at least a part of the crankshaft 20 immersed in the lubricating oil and the swing gear 24 swings, the notches 44c, 44c,.・ Oil flows through. For this reason, the flow of oil from the outside of the retainer 44 into the retainer 44 and the flow of oil from the inside of the retainer 44 to the outside of the retainer 44 are likely to occur. Therefore, it is possible to easily distribute the oil when the crankshaft 20 rotates forward and backward. In addition, since the cutout portion 44c has a cross-sectional shape that is recessed from the outer peripheral edge of the side wall 44a, the gap between the eccentric portion insertion hole 24c formed in the rocking gear 24 and the retainer 44 is small, or the side wall 44a. Even when the washer 30 is disposed adjacent to the rolling element 42, the oil permeability of the rolling oil to the rolling surface and the end surface of the rolling element 42 can be ensured.

  Moreover, in this embodiment, the notches 44c and 44c are formed at diagonal positions in the respective connecting portions 44b, so that the rolling elements 42 can be held in a balanced manner. Further, since the lubricating oil is directly supplied to the rolling surface of the rolling element 42 through the notches 44c, 44c,..., Wear or breakage due to poor lubrication can be effectively prevented.

  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 embodiment illustrated in FIG. 2 has been described as an example in which the notched portions 44c and 44c of the cage 44 are formed at diagonal positions in the connecting portion 44b. However, the embodiment is not limited to this embodiment. Absent. As shown in FIG. 5, the cutout portions 44c, 44c,... May be formed in all four corner portions of the connecting portion 44b. Even in this case, the notches 44c, 44c,... Are formed at diagonal positions in the connecting portion 44b. In this configuration, since the number of notches 44c, 44c,... Is increased as compared with the configuration of FIG. 2, the amount of lubricating oil can be increased accordingly. Also in this configuration, if the range of the length direction in which the cutout portion 44c is formed on the side surface of the connecting portion 44b is equal to or less than one half of the length of the connecting portion 44b, the adjacent connecting portions 44b and 44b. The rolling elements 42 positioned therebetween can be stably held.

  The notches 44c, 44c,... Are not limited to the configuration formed at the diagonal position of the connecting portion 44b. For example, as shown in FIGS. 6 and 7, the cutout portions 44c and 44c may be formed at the center portion in the width direction of the connecting portion 44b. In this configuration, the notches 44c and 44c are formed so as to penetrate the outer peripheral surface and the inner peripheral surface of the connecting portion 44b. In the embodiment shown in FIG. 6, notches 44c and 44c are formed on both sides of the connecting portion 44b except for the central portion in the length direction. In the embodiment shown in FIG. A notch 44c is formed over the whole.

  In this embodiment, the inflow of the lubricating oil into the cage 44 is secured by the notches 44c and 44c while maintaining a configuration in which the entire length of the connecting portion 44b is in contact with the rolling surface of the rolling element 42. be able to.

  In the embodiment, the example in which the connecting portions 44b, 44b,... Of the retainer 44 are formed in a linearly extending shape has been described, but the present invention is not limited to this. As shown in FIG. 8, even when the central portion of the connecting portions 44b, 44b,... Is bent so as to protrude inward, the cage 44 has a substantially M-shaped cross section. Good. The retainer 44 shown in FIG. 8 shows an example in which notches 44c and 44c are formed at diagonal positions of the connecting portion 44b as in FIG. 2, but the notches are shown in FIGS. 44c, 44c,... May be formed.

2 Outer cylinder 3 Internal tooth pin 4 Carrier 6 Main bearing 18 Crankshaft gear 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 31 Retaining ring 32 Base 32a Substrate Part 32b shaft part 34 end plate part 42 rolling element 44 cage 44a side wall 44b connecting part 44c notch part

Claims (4)

A crankshaft having an eccentric portion;
An input unit for inputting a driving force for rotating the crankshaft;
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 oscillating gear and the eccentric part, and
The eccentric part bearing has a plurality of cylindrical rolling elements, and a cage that holds the rolling elements,
The cage is formed in an annular shape surrounding the eccentric portion and is disposed between the pair of side walls disposed at intervals in the axial direction of the rolling elements, and the pair of rolling elements. A plurality of connecting portions that connect the side walls, and each side wall has a cross-sectional shape that is recessed from the outer peripheral edge of the side wall at a portion where the connecting portion is connected, and extends from the side walls to extend in the longitudinal direction of the connecting portion A notch formed across the connecting portion, and
The eccentric oscillating gear device , wherein the notch has a radial depth shallower than a radial thickness of the side wall, and is formed so as to extend from the outer peripheral surface to the inner peripheral surface of the connecting portion .   The eccentric oscillating gear device according to claim 1, wherein the notch is formed at a diagonal position in each connecting portion.   2. The eccentric oscillating gear device according to claim 1, wherein the notch is formed so as to penetrate an outer peripheral surface and an inner peripheral surface of the connecting portion at a center in a width direction of each connecting portion.   Further comprising a washer disposed on a side of the eccentric bearing;
  The said notch part is a shape which is a shape which is not obstruct | occluded by the said washer even in the place where the protrusion width | variety from the axial main body of the said crankshaft is the smallest in the said eccentric part. An eccentric oscillating gear device.

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