Rotating device

Abstract

The present invention provides a rotating device that allows lubricant to be distributed without requiring a redesign of the crankshaft, and consequently without compromising productivity. [Solution] In the embodiment of the reduction gear, the journal portion 13d of the crankshaft 13 is rotatably supported on the base portion 7 via a journal bearing 18, and the eccentric portion 13a rotatably supports the external gear 15 via an eccentric portion bearing 19. A first gap G1 is formed in part between the journal ring 65 of the journal cage 64 constituting the journal bearing 18 and the eccentric ring 75 of the eccentric cage 34 constituting the eccentric portion bearing 19.

Description

Technical Field

[0001] The present invention relates to a rotating device.

Background Art

[0002] Conventionally, a so-called eccentric oscillating speed reducer has been known as a rotating device. This type of rotating device includes an internal gear, two carriers that are rotatably supported by the internal gear and arranged opposite to each other in the rotation axis direction, a crankshaft that is rotatably supported by the carriers, and an external gear that is arranged between the respective carriers and meshes with the internal gear. The crankshaft has a journal portion (shaft support portion) supported by the carrier, and an eccentric portion eccentric with respect to the center of rotation.

[0003] The external gear is rotatably supported by the eccentric portion. Therefore, the external gear meshes with the internal gear while oscillating and rotating. For example, a rolling bearing is used as a bearing for rotatably supporting the crankshaft on the carrier or a bearing for rotatably supporting the external gear on the eccentric portion.

[0004] In order to improve the driving efficiency of such a rotating device, various techniques have been proposed to uniformly distribute a lubricant throughout the rotating device. For example, a technique in which a groove portion for guiding a lubricant to the eccentric portion is formed has been disclosed (see, for example, Patent Document 1). According to this, even if rolling bearings provided on the journal portion and the eccentric portion are arranged without gaps in the axial direction, the lubricant can be guided into the rolling bearings through the groove portion. Therefore, insufficient lubrication of the eccentric portion can be improved.

Prior Art Literature

Patent Literature

[0005]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0006] However, the conventional technology described above requires machining the crankshaft to improve the lack of lubrication in the eccentric portion, which necessitates a redesign of the crankshaft and has the drawback of reducing the productivity of rotating devices.

[0007] The present invention provides a rotating device that can distribute lubricant without requiring a redesign of the crankshaft and, consequently, without compromising productivity. [Means for solving the problem]

[0008] A rotating device according to one aspect of the present invention comprises a first member and a second member that rotate relative to each other, a first bearing provided on the first member, a second bearing provided on the second member, and a crankshaft having a journal portion and an eccentric portion eccentric with respect to the axis of the journal portion, wherein the journal portion and the eccentric portion are arranged side by side in the direction of the axis, the journal portion is rotatably supported on the first member via the first bearing, the eccentric portion rotatably supports the second member via the second bearing, the first bearing comprises a plurality of first rolling elements arranged side by side in the circumferential direction of the journal portion and rolling around the journal portion, and a first cage that holds the plurality of first rolling elements, and the second bearing is The first retainer comprises a plurality of second rolling elements arranged in a line in the circumferential direction of the eccentric portion and rolling around the eccentric portion, and a second retainer that holds the plurality of second rolling elements, wherein the first retainer comprises two first rings arranged opposite each other in the axial direction with the first rolling elements in between, and a plurality of first column portions that connect the two first rings and are arranged between adjacent first rolling elements in the circumferential direction, and the second retainer comprises two second rings arranged opposite each other in the axial direction with the second rolling elements in between, and a plurality of second column portions that connect the two second rings and are arranged between adjacent second rolling elements in the circumferential direction, with a gap formed in part between adjacent first and second rings in the axial direction.

[0009] With this configuration, even if the first and second bearings are arranged side by side in the axial direction, lubricant can be guided into the interior of each bearing through the gap between the first and second rings. Therefore, lubricant can be distributed throughout the rotating device without requiring any design changes to the crankshaft and thus without negatively impacting productivity.

[0010] In the above configuration, the overlapping area of ​​the first ring and the second ring is a part of the first ring and the second ring, respectively.

[0011] In the above configuration, the overlapping range of the first ring and the second ring is between 180° and 360° when viewed from the direction of the axis.

[0012] In the above configuration, when the outer diameter of the first ring is Do1, the inner diameter of the second ring is Di2, and the eccentricity of the eccentric portion with respect to the axis is E, the outer diameter Do1, the inner diameter Di2, and the eccentricity E satisfy Di2 / 2 > Do1 / 2 - 2 × E.

[0013] In the above configuration, the first ring has an outer chamfer formed on its outer circumference, and the second ring has an inner chamfer formed on the outer side of its inner circumference in the direction of the axis. The outer diameter of the first ring is Do1, the inner diameter of the second ring is Di2, the eccentricity of the eccentric portion with respect to the axis is E, the radial width between the outer circumference of the first ring and the radial inner edge of the outer chamfer of the first ring as viewed from the direction of the axis is Wo1, and the radial width between the inner circumference of the second ring and the radial outer edge of the inner chamfer of the second ring as viewed from the direction of the axis is Wi2. Then, the outer diameter Do1, the inner diameter Di2, the eccentricity E, and the widths Wo1 and Wi2 satisfy (D2 / 2+Wi2)>(D1 / 2-Wo1)-E.

[0014] Another aspect of the present invention relates to a rotating device comprising a first member and a second member that rotate relative to each other, a first bearing provided on the first member, a second bearing provided on the second member, and a crankshaft having a journal portion and two eccentric portions eccentric to the axis of the journal portion, wherein the two eccentric portions are arranged side by side in the direction of the axis and are 180° out of phase, the journal portion is rotatably supported on the first member via the first bearing, and the eccentric portions rotatably support the second member via the second bearing. The second bearing comprises a plurality of second rolling elements arranged in the circumferential direction of the eccentric portion and rolling around the eccentric portion, and a second cage that holds the plurality of second rolling elements, the second cage comprising two second rings arranged opposite each other in the axial direction with the second rolling elements in between, and a plurality of second column portions connecting the two second rings and positioned between adjacent second rolling elements in the circumferential direction, a gap formed in part between two adjacent second rings in the axial direction of each of the two second bearings.

[0015] With this configuration, even if the two second bearings are arranged side by side in the axial direction, lubricant can be guided into the interior of each second bearing through the gap between adjacent second bearings in the axial direction. Therefore, lubricant can be distributed throughout the rotating device without requiring any design changes to the crankshaft, and consequently without negatively impacting productivity.

[0016] In the above configuration, the gaps are formed on both sides in the radial direction with respect to the axis.

[0017] In the above configuration, when the inner diameter of the second ring is Di2, the outer diameter of the second ring is Do2, and the eccentricity of the eccentric portion with respect to the axis is E, the inner diameter Di2, the outer diameter Do2, and the eccentricity E satisfy Di2 / 2 > Do2 / 2 - 2 × E.

[0018] In the above configuration, the second ring comprises: a second ring inner chamfer formed on an outer side in the axial direction among the inner circumference of the second ring; and a second ring outer chamfer formed on the outer circumference of the second ring; where Di2 represents an inner diameter of the second ring, Do2 represents an outer diameter of the second ring, E represents an eccentricity amount of the eccentric portion with respect to the axis, Wi2 represents a radial width between the inner circumference of the second ring and a radially outer edge of the second ring inner chamfer as viewed from the axial direction, and Wo2 represents a radial width between the outer circumference of the second ring and a radially inner edge of the second ring outer chamfer as viewed from the axial direction, the inner diameter Di2, the outer diameter Do2, the eccentricity amount E, and the widths Wi2 and Wo2 satisfy (Di2+Wi2)>(Do2-Wo2)-E.

[0019] In the above configuration, the device comprises: a cylindrical case having an internal gear; two carriers rotatably supported radially inside the case and arranged side by side in the axial direction; and an external gear arranged between the two carriers and meshed with the internal gear, wherein the first member includes the two carriers, and the second member includes the external gear. Effects of the Invention

[0020] The rotating device described above does not require design changes to a crankshaft, and thus can allow a lubricant to spread throughout the inside thereof without deteriorating productivity. Brief Description of the Drawings

[0021] [Figure 1] Fig. 1 is a cross-sectional view of a reduction gear according to an embodiment of the present invention. [Figure 2] Fig. 2 is an enlarged view of section II in Fig. 1. [Figure 3] Fig. 3 is an enlarged view of section III in Fig. 2. [Figure 4] Fig. 4 is a plan view of a journal ring and an eccentric ring according to an embodiment of the present invention, as viewed from the outer side in the axial direction. [Figure 5] Fig. 5 is a plan view of two eccentric rings according to an embodiment of the present invention, as viewed from the axial direction. [Figure 6]It is a plan view of a journal ring and an eccentric ring in a modification of an embodiment of the present invention, viewed from the axially outer side. [Figure 7] It is a plan view of two eccentric rings in a modification of an embodiment of the present invention, viewed in the axial direction.

Mode for Carrying Out the Invention

[0022] Next, embodiments of the present invention will be described with reference to the drawings.

[0023] <Speed Reducer> Figure 1 is a cross-sectional view of a speed reducer 1 that is a rotating device. As shown in Figure 1, the speed reducer 1, for example, reduces the rotation of an unillustrated electric motor and outputs the reduced rotation. The speed reducer 1 is a so-called eccentric oscillation type speed reducer. The speed reducer 1 includes a cylindrical case 2, a carrier 3 rotatably provided radially inward of the case 2, and a speed reduction mechanism 4 connected to the carrier 3. The central axis of the case 2 coincides with the rotation axis of the carrier 3. In the following description, the common name for these central axis and rotation axis is referred to as the first rotation axis A1. A direction parallel to the first rotation axis A1 is referred to as the axial direction. The rotation direction of the carrier 3 is referred to as the circumferential direction. The radial direction of the case 2 orthogonal to both the axial direction and the circumferential direction is simply referred to as the radial direction.

[0024] <Case> On the outer peripheral surface of the case 2, an outer flange portion 2a projecting radially outward is integrally formed. A plurality of bolt holes 2b into which unillustrated bolts are inserted are formed in the outer flange portion 2a. The bolt holes 2b are arranged at equal intervals in the circumferential direction. Unillustrated bolts are inserted into the bolt holes 2b, and the speed reducer 1 is fixed by tightening the bolts to, for example, an arm of an industrial robot.

[0025] Multiple pin grooves 2c are formed on the inner circumferential surface of case 2, oriented along the axial direction. The pin grooves 2c are arranged at equal intervals in the circumferential direction. An internal tooth pin 5 is fitted into each pin groove 2c. The internal tooth pin 5 functions as an internal tooth that meshes with the external gears 15 and 16 of the reduction mechanism 4, which will be described later. Main bearings 6 are provided on both sides of the inner circumferential surface of case 2 in the axial direction. The carrier 3 is rotatably supported by case 2 via the main bearings 6. The main bearings 6 are, for example, tapered roller bearings.

[0026] <Career> The carrier 3 comprises a disc-shaped base portion 7 and an end plate portion 8 arranged opposite each other in the axial direction, and three column portions 9 that protrude from the base portion 7 toward the end plate portion 8. Each column portion 9 is arranged at equal intervals in the circumferential direction. An end plate portion 8 is placed on the tip 9a of each column portion 9. The end plate portion 8 is fixed to the column portion 9 by bolts 10. In this state, a space having a constant width in the axial direction is formed between the base portion 7 and the end plate portion 8. A pin hole 12a is formed radially inward from the bolt 10 of the column portion 9. A pin 11 is inserted or press-fitted into the pin hole 12a. The pin 11 positions the end plate portion 8 relative to the base plate portion 7. The pin 11 is also inserted or press-fitted into a pin hole 12b provided in the end plate portion 8.

[0027] The outer circumferential surfaces of the base plate portion 7 and the end plate portion 8 are rotatably supported by the case 2 via corresponding main bearings 6. Shaft insertion holes 7a and 8a are formed at the radial center of the base plate portion 7 and the radial center of the end plate portion 8, respectively. The two shaft insertion holes 7a and 8a are arranged coaxially.

[0028] On one surface 7c of the base plate portion 7 on the end plate portion 8 side, three crank insertion recesses 7b are formed between adjacent column portions 9 in the circumferential direction. The crank insertion recesses 7b are formed in a circular shape when viewed from the axial direction. Through holes 7d are formed at the bottom of the crank insertion recesses 7b. The through holes 7d are arranged coaxially with the crank insertion recesses 7b.

[0029] The end plate portion 8 has three crank insertion holes 8b formed coaxially with each crank insertion recess 7b. That is, the central axis A2 of the axially opposing crank insertion recesses 7b and crank insertion holes 8b is parallel to the first rotation axis A1. Each of these crank insertion recesses 7b and crank insertion holes 8b is provided with a journal bearing (an example of the first bearing in the claim) 18. The axial movement of the journal bearing 18 is restricted by corresponding positioning rings 25 and 26. Details of the journal bearing 18 will be described later.

[0030] <Deceleration mechanism> The reduction mechanism 4 rotates the carrier 3 at a rotational speed reduced by a constant ratio to the rotational speed of the motor shaft of an electric motor (not shown), for example. The reduction mechanism 4 comprises three crankshafts 13 inserted into each crank insertion recess 7b and each crank insertion hole 8b, a transmission spur gear 14 provided at the axial end of each crankshaft 13, and two external gears 15, 16 (first external gear 15, second external gear 16) provided between the base plate portion 7 and the end plate portion 8.

[0031] The transmission spur gear 14 meshes with a motor shaft (not shown). This transmits the rotation of the electric motor to the transmission spur gear 14, causing the transmission spur gear 14 to rotate.

[0032] Each crankshaft 13 is rotatably supported on the carrier 3 (base plate portion 7 and end plate portion 8) via each journal bearing 18. The crankshaft 13 has a shaft body 13c that rotates about a central axis A2, a first eccentric portion 13a and a second eccentric portion 13b formed in the axial center of the shaft body 13c, and journal portions 13d formed on both sides in the axial direction, flanking each eccentric portion 13a and 13b.

[0033] The axial diameter of the journal section 13d is larger than the axial diameter of the shaft body 13c. The journal section 13d is arranged coaxially with the shaft body 13c. The journal section 13d is rotatably supported by the carrier 3 (base plate section 7 and end plate section 8) via the journal bearing 18. In the following explanation, both sides of the shaft body 13c in the axial direction will be referred to as the axial outer side. The axial central side of the shaft body 13c where each eccentric portion 13a, 13b is located will simply be referred to as the axial central side.

[0034] The outer axial end face of the journal portion 13d on the substrate portion 7 side abuts against a positioning ring 25 provided in the crank insertion recess 7b of the substrate portion 7. The outer axial end face of the journal portion 13d on the end plate portion 8 side abuts against a positioning ring 26 provided in the crank insertion hole 8b of the end plate portion 8. This allows for axial positioning of the crankshaft 13.

[0035] The shaft body 13c and the transmission spur gear 14 are arranged coaxially and integrated. That is, the crankshaft 13 and the transmission spur gear 14 rotate together around the central axis A2. Hereinafter, the central axis A2 will be referred to as the second rotation axis A2 of the crankshaft 13. The second rotation axis A2 is an example of an axis in the claim.

[0036] The shaft diameters of the first eccentric portion 13a and the second eccentric portion 13b are equivalent to the shaft diameter of the journal portion 13d. The first eccentric portion 13a and the second eccentric portion 13b are eccentric from the second rotation axis A2. The first eccentric portion 13a and the second eccentric portion 13b are positioned adjacent to each other in the axial direction between the two journal bearings 18. The first eccentric portion 13a and the second eccentric portion 13b are positioned with a phase angle offset of 180°.

[0037] Each eccentric portion 13a, 13b is provided with an eccentric portion bearing (an example of a second bearing in the claim) 19. The two eccentric portion bearings 19 are arranged side by side in the axial direction, as well as side by side with the journal bearing 18 in the axial direction. The arrangement of the bearings 18, 19 side by side in the axial direction restricts the axial movement of each bearing 18, 19. A first external gear 15 and a second external gear 16 are rotatably supported on each crankshaft 13 via an eccentric bearing 19. Details of the eccentric bearing 19 will be described later.

[0038] The first external gear 15 and the second external gear 16 are positioned in the space between the base plate portion 7 and the end plate portion 8. The first external gear 15 and the second external gear 16 oscillate in conjunction with the rotation of the crankshaft 13. Specifically, the first external gear 15 and the second external gear 16 have through holes 15a and 16a formed therein, through which eccentric bearings 19 are provided. As a result, when the first eccentric portion 13a and the second eccentric portion 13b oscillate due to the rotation of the crankshaft 13, the first external gear 15 and the second external gear 16 oscillate via the eccentric bearings 19.

[0039] The first external gear 15 and the second external gear 16 each have openings 15b and 16b, respectively, to avoid interference with the column portion 9. Shaft insertion holes 15c and 16c are formed in the radial center of the first external gear 15 and the second external gear 16. External teeth 15d and 16d are formed on the outer circumference of the first external gear 15 and the outer circumference of the second external gear 16, respectively. The number of teeth on each external tooth 15d and 16d is, for example, one less than the number of internal tooth pins 5 of case 2.

[0040] <Journal bearings and eccentric bearings> Figure 2 is an enlarged view of part II of Figure 1. Figure 3 is an enlarged view of part III of Figure 2. As shown in Figures 1 to 3, the journal bearing 18 and the eccentric bearing 19 are needle roller bearings.

[0041] Each of the two journal bearings 18 comprises an annular journal inner ring 61 integrated with the journal portion 13d of the crankshaft 13, an annular journal outer ring 62 integrated with the base portion 7 and the end plate portion 8, a plurality of journal rolling elements (an example of the first rolling element in the claim) 63 arranged between the journal inner ring 61 and the journal outer ring 62, and a journal retainer (an example of the first retainer in the claim) 64 that holds the journal rolling elements 63. The journal rolling elements 63 are needle rollers arranged parallel to the axial direction.

[0042] The journal rolling elements 63 are arranged in the circumferential direction of the journal inner ring 61 and the journal outer ring 62. In other words, the journal rolling elements 63 roll around the journal portion 13d.

[0043] The journal holder 64 is integrally molded with two annular journal rings (an example of the first ring in the claim) 65 arranged opposite each other in the axial direction, sandwiching the journal rolling elements 63, and a journal column (the first column in the claim) 66 connecting the two journal rings 65. The journal column 66 extends in the axial direction and is arranged at equal intervals in the circumferential direction. Each journal rolling element 63 is housed in one of several journal pockets 67, each partitioned by the journal column 66 and the two journal rings 65. As a result, the journal rolling elements 63 are held in the journal holder 64.

[0044] Each of the two eccentric bearings 19 comprises an annular eccentric inner ring 31 integrated with each eccentric portion 13a, 13b of the crankshaft 13, an annular eccentric outer ring 32 integrated with each external gear 15, 16, a plurality of eccentric rolling elements (an example of the second rolling element in the claim) 33 positioned between the eccentric inner ring 31 and the eccentric outer ring 32, and an eccentric cage (an example of the second cage in the claim) 34 that holds the eccentric rolling elements 33. The eccentric rolling elements 33 are needle rollers arranged parallel to the axial direction.

[0045] The eccentric rolling elements 33 are arranged in the circumferential direction of the eccentric inner ring 31 and the eccentric outer ring 32. In other words, the eccentric rolling elements 33 roll around the eccentric portions 13a and 13b.

[0046] The eccentric retainer 34 is integrally molded with two annular eccentric rings (an example of the second ring in the claim) 75 arranged opposite each other in the axial direction, sandwiching the eccentric rolling element 33, and an eccentric column portion (the second column portion in the claim) 76 connecting the two eccentric rings 75. The eccentric column portion 76 extends in the axial direction and is arranged at equal intervals in the circumferential direction. Each eccentric rolling element 33 is housed in one of a plurality of eccentric pocket portions 77, each partitioned by the respective eccentric column portion 76 and the two eccentric rings 75. As a result, the eccentric rolling element 33 is held in the eccentric retainer 34.

[0047] Each of these retainers 34, 64 is formed of resin. For example, a glass-containing nylon resin can be used as the resin. However, it is not limited to this, and various resins can be used. The retainers 34, 64 are not limited to resin; they can also be formed from metal.

[0048] <Regarding the gap structure between each retainer> Here, a first gap G1 is formed in part between two axially adjacent journal retainers 64 and eccentric retainers 34. A second gap G2 is formed in part between two axially adjacent eccentric retainers 34. The configurations in which these gaps G1 and G2 are formed will be described in detail below.

[0049] First, let's explain the first gap G1. Figure 4 is a plan view of the journal ring 65 and the eccentric ring 75 as seen from the outside in the axial direction. As shown in Figure 4, the journal ring 65 and the eccentric ring 75 are in contact in part (see the first region Ar1 shown by hatching in Figure 4). In other words, the journal ring 65 and the eccentric ring 75 overlap only in part when viewed from the axial direction. As a result, the first gap G1 is formed in the area where the journal ring 65 and the eccentric ring 75 are not in contact when viewed from the axial direction.

[0050] The range θ1 of the first region Ar1 as viewed from the axial direction is between 180° and 360° (hereinafter referred to as Condition 1). Range θ1 refers to the angle between two first lines L1 that connect the second rotation axis A2 and the two circumferential ends in the first region Ar1. To satisfy condition 1, more specifically, the predetermined dimensions are determined as follows. That is, as shown in Figure 2, when the outer diameter of the journal ring 65 is Do1, the inner diameter of the eccentric ring 75 is Di2, and the eccentricity of each eccentric part 13a, 13b with respect to the second rotation axis A2 is E, then the outer diameter Do1 of the journal ring 65, the inner diameter Di2 of the eccentric ring 75, and the eccentricity E are: Di2 / 2>Do1 / 2-2×E ···(1) It satisfies the condition.

[0051] To satisfy condition 1, it is also possible to configure it as follows. Specifically, as shown in Figure 3, a journal outer chamfer (an example of the first ring outer chamfer in the claim) 65a is formed on the outer circumference of the journal ring 65. An eccentric inner chamfer 75a is formed on the outer corner in the axial direction of the inner circumference of the eccentric ring 75, that is, on the corner on the journal ring 65 side. Each chamfer 65a, 75a is formed flat.

[0052] Under this configuration, when the radial width of the journal outer bevel portion 65a as viewed from the axial direction (hereinafter simply referred to as the width of the journal outer bevel portion 65a) is Wo1, and the radial width of the eccentric inner bevel portion 75a (hereinafter simply referred to as the width of the eccentric inner bevel portion 75a) is Wi2, then the outer diameter Do1 of the journal ring 65, the inner diameter Di2 of the eccentric ring 75, the eccentricity E, the width Wo1 of the journal outer bevel portion 65a, and the width Wi2 of the eccentric inner bevel portion 75a are: (D2 / 2+Wi2)>(D1 / 2-Wo1)-E ···(2) It satisfies the condition.

[0053] The width Wo1 of the journal outer bevel 65a refers, more specifically, to the radial width between the outer circumference of the journal ring 65 and the inner edge of the journal outer bevel 65a as viewed from the axial direction. The width Wi2 of the eccentric inner bevel 75a refers, more specifically, to the radial width between the inner circumference of the eccentric ring 75 and the radial outer edge of the eccentric inner bevel 75a as viewed from the axial direction. If the above equation (1) is satisfied, the journal outer planar section 65a and the eccentric inner planar section 75a are not required components.

[0054] Next, we will explain the second gap G2. Figure 5 is a plan view of the two eccentric rings 75 as seen from the axial direction. As shown in Figure 5, the two eccentric rings 75 each have a second gap G2 formed on both radial sides around the second rotation axis A2. In other words, the two eccentric rings 75 are in contact on a portion of both radial sides around the second rotation axis A2 (second region Ar2 shown by hatching in Figure 5). To put it another way, the two eccentric rings 75 overlap only on both radial sides around the second rotation axis A2 when viewed from the axial direction.

[0055] In order to satisfy the conditions for the formation of the second gap G2 (referred to as condition 2), more specifically, the predetermined dimensions are determined as follows. That is, as shown in Figure 2, when the outer diameter of the eccentric ring 75 is Do2, the outer diameter Do2 of the eccentric ring 75, the inner diameter Di2 of the eccentric ring 75, and the eccentricity E are: Di2 / 2>Do2 / 2-2×E ···(3) It satisfies the condition.

[0056] To satisfy condition 2, it is also possible to configure it as follows. Specifically, as shown in Figure 3, an eccentric inner flat surface portion 75a is formed on the eccentric ring 75, and an eccentric outer flat surface portion 75b is formed on the outer circumference of the eccentric ring 75. The eccentric outer flat surface portion 75b is also formed flat, similar to the eccentric inner flat surface portion 75a.

[0057] Under this configuration, when the radial width of the eccentric outer planar portion 75b as viewed from the axial direction (hereinafter simply referred to as the width of the eccentric outer planar portion 75b) is Wo2, the outer diameter Do2 of the eccentric ring 75, the inner diameter Di2 of the eccentric ring 75, the amount of eccentricity E, the width Wi2 of the eccentric inner planar portion 75a, and the width Wo2 of the eccentric outer planar portion 75b are: (Di2+Wi2)>(Do2-Wo2)-E ···(4) It satisfies the condition.

[0058] The width Wo2 of the eccentric outer bevel portion 75b refers, more specifically, to the radial width between the outer circumference of the eccentric ring 75 and the radial inner edge of the eccentric outer bevel portion 75b as viewed from the axial direction. If the above equation (3) is satisfied, the eccentric inner planar section 75a and the eccentric outer planar section 75b are not required components.

[0059] <Operation of the speed reducer> Next, the operation of the reduction gear 1 will be explained. An electric motor (not shown) causes the transmission spur gear 14 and the crankshaft 13 to rotate together. Furthermore, the first external gear 15 and the second external gear 16 are rotated in an oscillating motion. As a result of this oscillating motion, some of the external teeth 15d and 16d of each external gear 15 and 16 engage with the internal tooth pin 5 of case 2. The number of teeth on each external tooth 15d and 16d is, for example, one less than the number of internal tooth pins 5. Therefore, each external gear 15 and 16 rotates such that the engagement points of each external tooth 15d and 16d with respect to the internal tooth pin 5 (case 2) are sequentially shifted in the circumferential direction. This rotation is decelerated relative to the rotation of the crankshaft 13.

[0060] As each external gear 15 and 16 rotates, each crankshaft 13 also rotates on its own axis around the second rotation axis A2 while revolving around the first rotation axis A1. Each crankshaft 13 is rotatably supported on the carrier 3 (base plate portion 7, end plate portion 8). Therefore, the carrier 3 rotates in conjunction with the revolution of each crankshaft 13. As a result, the reduction gear 1 reduces the rotation of an electric motor (motor shaft) (not shown) and outputs it from the carrier 3. If the carrier 3 is fixed to the arm of an industrial robot, the reduction gear 1 can reduce the rotation of the electric motor and output it from the case 2.

[0061] Incidentally, each bearing 18, 19 attached to the crankshaft 13 is filled with sufficient lubricant to improve the driving efficiency of the reduction gear 1. When the crankshaft 13 rotates, centrifugal force acts on this lubricant. As a result, the lubricant tends to accumulate on the outer circumference of each bearing 18, 19. Also, if the journal cages 64 and eccentric cages 34 that are aligned in the axial direction are in contact, or if two eccentric cages 34 are in contact with each other, the space between each cage 64, 34 tends to fill up. Therefore, it is difficult for the lubricant that has accumulated on the outer circumference to flow back into each bearing 18, 19.

[0062] However, in each of the cages 64, 34 in the reduction gear 1 described above, a first gap G1 is formed in part between the journal ring 65 and the eccentric ring 75. Therefore, lubricant can be guided into the interior of each bearing 18, 19 through the first gap G1. As a result, lubricant can be distributed throughout the interior of the reduction gear 1. No additional machining or redesign of the crankshaft 13 is required to guide lubricant into the interior of each bearing 18, 19. This prevents a decrease in the productivity of the reduction gear 1.

[0063] The overlapping area between the journal ring 65 and the eccentric ring 75 is a portion of both the journal ring 65 and the eccentric ring 75. This configuration allows for the easy formation of a first gap G1 between the journal ring 65 and the eccentric ring 75. The area where the journal ring 65 and the eccentric ring 75 overlap satisfies condition 1. Therefore, when the journal ring 65 and the eccentric ring 75 come into contact, it is possible to prevent the load on each ring 65 and 75 from being unevenly distributed and causing each ring 65 and 75 to tilt.

[0064] To satisfy condition 1, the journal ring 65 and the eccentric ring 75 satisfy the above formula (1). Therefore, there is no need to make the journal ring 65 or the eccentric ring 75 have complex shapes, and the journal ring 65 and the eccentric ring 75 can be easily formed. Another way to satisfy condition 1 is to form an outer journal surface 65a on the journal ring 65 and an eccentric inner surface 75a on the eccentric ring 75. In this case, the above equation (2) is satisfied. Even in this case, it is not necessary to make the journal ring 65 or the eccentric ring 75 into a complex shape. For this reason, the journal ring 65 and the eccentric ring 75 can be easily formed.

[0065] A second gap G2 is formed between the two eccentric retainers 34 in the reduction gear 1 described above. Therefore, lubricant can be guided into the interior of the two eccentric retainers 34 through the second gap G2. Thus, lubricant can be distributed throughout the interior of the reduction gear 1. To guide lubricant into the eccentric bearing 19, no additional machining or redesign of the crankshaft 13 is required. This prevents a decrease in the productivity of the reduction gear 1.

[0066] The second gap G2 is formed on both sides of the crankshaft 13 in the radial direction, centered on the second rotation axis A2. This allows the lubricant to be guided evenly in the circumferential direction into the interior of the eccentric bearing 19. Furthermore, the two eccentric bearings 19 can be made to contact each other evenly when viewed from the axial direction. This prevents the eccentric bearings 19 from tilting due to uneven contact when they come into contact with each other.

[0067] In order to satisfy condition 2 for forming the second gap G2, the eccentric ring 75 satisfies the above equation (3). Therefore, there is no need to make the eccentric ring 75 a complex shape, and it can be easily formed. Another way to satisfy condition 2 is to form an eccentric inner planar portion 75a and an eccentric outer planar portion 75b on the eccentric ring 75. In this case, the above equation (4) is satisfied. Even in this case, it is not necessary to make the eccentric ring 75 a complex shape, and it can be easily formed.

[0068] The reduction gear 1 is a so-called oscillating gear reduction gear. Because such a reduction gear has little internal clearance, the configuration of each retainer 34, 64 as described above is preferable.

[0069] [Differentiation] In the embodiments described above, the case where formulas (1) and (2) above are satisfied in order to form a first gap G1 in a portion between the journal ring 65 and the eccentric ring 75 was explained. The case where formulas (3) and (4) above are satisfied in order to form a second gap G2 in a portion between the two eccentric rings 75 was explained. However, the invention is not limited to these, and the journal ring 65 and the eccentric ring 75 may be configured to form the first gap G1 and the second gap G2. An example will be described in detail below.

[0070] Figure 6 is a plan view of the journal ring 65 and eccentric ring 75 in the modified example, viewed from the outside in the axial direction. Figure 6 corresponds to Figure 4 mentioned above. Figure 7 is a plan view of the two eccentric rings 75 in the modified example, viewed from the axial direction. Figure 7 corresponds to Figure 5 mentioned above. As shown in Figures 6 and 7, the modified eccentric ring 75 has a plurality of recesses 75c formed on its inner circumference. The plurality of recesses 75c are arranged at equal intervals in the circumferential direction. The plurality of recesses 75c are formed in a semicircular shape. However, it is not limited to this, and the shape of the recesses 75c can be arbitrarily determined, for example, a triangular shape or a square shape.

[0071] As shown in Figure 6, the formation of the recess 75c causes the journal ring 65 and the eccentric ring 75 to be in contact in part (see the first region Ar1 shown by hatching in Figure 6). In other words, the journal ring 65 and the eccentric ring 75 overlap only in part when viewed from the axial direction. In other words, the journal ring 65 and the eccentric ring 75 are not in contact in part when viewed from the axial direction where the recess 75c is formed. The first gap G1 is formed in this non-contact area.

[0072] As shown in Figure 7, the formation of the recess 75c creates a second gap G2 on each of the two eccentric rings 75 in the radial direction around the second rotation axis A2. In other words, the two eccentric rings 75 are in contact on parts of both radial sides around the second rotation axis A2 (second region Ar2 shown by hatching in Figure 7). To put it another way, the two eccentric rings 75 are not in contact when viewed from the axial direction in parts where the recess 75c is formed. The second gap G2 is formed in these non-contacting areas. Therefore, according to the above modification, the same effects as those of the previously described embodiment are achieved.

[0073] [Other variations] The present invention is not limited to the embodiments described above, and includes various modifications to the embodiments described above, without departing from the spirit of the invention.

[0074] For example, in the above-described embodiment, an eccentric oscillating type reduction gear 1 was described as an example of a rotating device, and the case in which journal bearings 18 and eccentric bearings 19 are provided in this reduction gear 1 was described. However, it is not limited to this, and the configuration of journal bearings 18 and eccentric bearings 19 can be adopted for the crankshaft 13 and various rotating devices that use bearings in the crankshaft 13.

[0075] It is not necessary for the journal inner ring 61 to be integrally molded with the journal portion 13d, nor for the eccentric inner ring 31 to be integrally molded with the eccentric portions 13a and 13b. It is not necessary for the journal outer ring 62 to be integrally molded with the carrier 3 (base portion 7, end plate portion 8), nor for the eccentric outer ring 32 to be integrally molded with the external gears 15 and 16. It is sufficient that the journal rolling elements 63 roll around the journal portion 13d. It is sufficient that the eccentric rolling elements 33 roll around the eccentric portions 13a and 13b.

[0076] In the embodiments described above, the journal bearing 18 and the eccentric bearing 19 were described as needle roller bearings. However, the configuration of the journal bearing 18 and the eccentric bearing 19 can be adopted for various bearings having rolling elements and cages.

[0077] In the above-described embodiment, the reduction gear 1 was described as having multiple (for example, three) crankshafts 13 as an eccentric oscillating reduction gear. However, it is not limited to this, and in this type of reduction gear, there may be only one crankshaft 13. In this case, the crankshaft 13 is arranged coaxially with the first rotation axis A1.

[0078] In the above-described embodiment, the case in which the reduction gear 1 is equipped with two external gears 15 and 16 was explained. However, it is not limited to this, and it is sufficient to have at least one external gear. It may also be equipped with three or more external gears. The number of eccentric parts can be changed according to the number of external gears. Even in this configuration, it is possible to satisfy the function of an eccentric oscillating type reduction gear.

[0079] In the embodiments described above, the journal inner ring 61 of the journal bearing 18 was described as being integrated with the journal portion 13d of the crankshaft 13. However, the invention is not limited to this, and the journal inner ring 61 may be configured separately from the journal portion 13d. The case described above involves the journal outer ring 62 of the journal bearing 18 being integrated with the base plate portion 7 and the end plate portion 8. However, the case is not limited to this, and the journal outer ring 62 may be constructed separately from the base plate portion 7 and the end plate portion 8.

[0080] Among the embodiments disclosed herein, those composed of multiple objects may be integrated, and conversely, those composed of a single object may be divided into multiple objects. Whether or not they are integrated, the invention can be constructed in a way that achieves its objective. [Explanation of Symbols]

[0081] 1…Reduction gear (rotating wheel device) 2…case 3…Carrier (first component) 7… Circuit board section (carrier, first component) 8…End plate section (carrier, first member) 13…Crankshaft 13a...First eccentric part (eccentric part) 13b…Second eccentric part (eccentric part) 13d...Journal Department 15…First external gear (external gear, second component) 16…Second external gear (external gear, second component) 18…Journal bearing (first bearing) 19…Eccentric bearing (second bearing) 33...Eccentric rolling element (second rolling element) 34...Eccentric cage (second cage) 63…Journal rolling element (first rolling element) 64…Journal holder (first holder) 65…Journaling ring (first ring) 66…Journal column (first column) 75…Eccentric ring (second ring) 76...Eccentric column part (second column part) Di2…Inner diameter of the eccentric ring (inner diameter of the second ring) Do1…Outer diameter of the journal ring (outer diameter of the first ring) Do2…Outer diameter of the eccentric ring (outer diameter of the second ring) E... Eccentricity G1...First gap (gap) G2... Second gap Wi2…Width of the eccentric inner planar section (radial width between the radial outer edge of the inner surface section of the second ring) Wo1…Width of the journal outer chamfer (radial width between the radial inner edge of the first ring outer chamfer) Wo2…Width of the eccentric outer chamfer (radial width between the radial inner edge of the outer chamfer of the second ring)

Claims

1. A first member and a second member that rotate relative to each other, The first bearing provided on the first member, The second bearing provided on the second member, A crankshaft having a journal portion and an eccentric portion that is eccentric with respect to the axis of the journal portion, Equipped with, The journal portion and the eccentric portion are arranged side by side in the direction of the axis. The journal portion is rotatably supported on the first member via the first bearing. The eccentric portion rotatably supports the second member via the second bearing, The first bearing is, A plurality of first rolling elements are arranged in the circumferential direction of the journal portion and roll around the journal portion, A first retainer that holds the plurality of first rolling elements, Equipped with, The second bearing is, A plurality of second rolling elements are arranged in the circumferential direction of the eccentric portion and roll around the eccentric portion, A second retainer that holds the plurality of second rolling elements, Equipped with, The first retainer is, Two first rings are arranged opposite each other in the direction of the aforementioned axis, with the first rolling element in between. The two first rings are connected, and a plurality of first column portions are arranged between the first rolling elements that are adjacent to each other in the circumferential direction, Equipped with, The second retainer is, Two second rings are arranged opposite each other in the direction of the aforementioned axis, with the second rolling element in between. The two second rings are connected, and a plurality of second column portions are arranged between the circumferentially adjacent second rolling elements, Equipped with, A gap is formed between the first ring and the second ring, which are adjacent to each other in the direction of the aforementioned axis. Rotating device.

2. The overlapping area of ​​the first ring and the second ring is a part of the first ring and the second ring, respectively. The rotating device according to claim 1.

3. The overlapping range of the first ring and the second ring is 180° to 360° when viewed from the direction of the axis. The rotating device according to claim 2.

4. When the outer diameter of the first ring is Do1, the inner diameter of the second ring is Di2, and the eccentricity of the eccentric portion with respect to the axis is E, then the outer diameter Do1, the inner diameter Di2, and the eccentricity E are: Di2 / 2>Do1 / 2-2×E Satisfying The rotating device according to any one of claims 1 to 3.

5. The first ring outer chamfer portion formed on the outer circumference of the first ring, The inner surface portion of the second ring, formed on the outer side of the inner circumference of the second ring in the direction of the axis, It has, When the outer diameter of the first ring is Do1, the inner diameter of the second ring is Di2, the eccentricity of the eccentric portion with respect to the axis is E, the radial width between the outer circumference of the first ring and the radially inner edge of the outer chamfer of the first ring as viewed from the direction of the axis is Wo1, and the radial width between the inner circumference of the second ring and the radially outer edge of the inner chamfer of the second ring as viewed from the direction of the axis is Wi2, then the outer diameter Do1, the inner diameter Di2, the eccentricity E, and the widths W1 and Wi2 are, (D2 / 2+Wi2)>(D1 / 2-Wo1)-E Satisfying The rotating device according to any one of claims 1 to 3.

6. A first member and a second member that rotate relative to each other, The first bearing provided on the first member, The second bearing provided on the second member, A crankshaft having a journal portion and two eccentric portions that are eccentric with respect to the axis of the journal portion, Equipped with, The two eccentric portions are arranged side by side in the direction of the axis and are positioned with a 180° phase difference. The journal portion is rotatably supported on the first member via the first bearing. The eccentric portion rotatably supports the second member via the second bearing, The second bearing is, A plurality of second rolling elements are arranged in the circumferential direction of the eccentric portion and roll around the eccentric portion, A second retainer that holds the plurality of second rolling elements, Equipped with, The second retainer is, Two second rings are arranged opposite each other in the direction of the aforementioned axis, with the second rolling element in between. The two second rings are connected, and a plurality of second column portions are arranged between the circumferentially adjacent second rolling elements, Equipped with, In each of the two second bearings, a gap is formed between two adjacent second rings in the axial direction. Rotating device.

7. The gaps are formed on both sides in the radial direction with respect to the aforementioned axis. The rotating device according to claim 6.

8. When the inner diameter of the second ring is Di2, the outer diameter of the second ring is Do2, and the eccentricity of the eccentric portion with respect to the axis is E, then the inner diameter Di2, the outer diameter Do2, and the eccentricity E are, Di2 / 2>Do2 / 2-2×E Satisfying The rotating device according to claim 6 or claim 7.

9. The inner surface portion of the second ring, formed on the outer side of the inner circumference of the second ring in the direction of the axis, The second ring outer chamfer portion formed on the outer circumference of the second ring, It has, When the inner diameter of the second ring is Di2, the outer diameter of the second ring is Do2, the eccentricity of the eccentric portion with respect to the axis is E, the radial width between the inner circumference of the second ring and the radial outer edge of the inner chamfer of the second ring as viewed from the direction of the axis is Wi2, and the radial width between the outer circumference of the second ring and the radial inner edge of the outer chamfer of the second ring as viewed from the direction of the axis is Wo2, The inner diameter Di2, the outer diameter Do2, the eccentricity E, and the widths Wi2, Wo2 are, (Di2+Wi2)>(Do2-Wo2)-E Satisfying The rotating device according to claim 6 or claim 7.

10. A cylindrical case having an internal gear, Two carriers are rotatably supported radially inward of the case and are arranged side by side in the direction of the axis, An external gear is positioned between the two carriers and meshes with the internal gear, Equipped with, The first member includes the two carriers, The second member includes the external gear, The rotating device according to claim 1 or claim 6.

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