rotating device

Abstract

The present application provides a rotating device. In the reduction gear of the embodiment, the journal portion (13d) of the crankshaft (13) is rotatably supported to the base plate portion (7) by means of the journal bearing (18), and the eccentric portion (13a) rotatably supports the outer gear (15) by means of the eccentric bearing (19). Between the journal ring (65) of the journal retainer (64) constituting the journal bearing (18) and the eccentric ring (75) of the eccentric retainer (34) constituting the eccentric bearing (19), a first gap (G1) is locally formed.

Description

Technical Field

[0001] This invention relates to a rotating device. Background Technology

[0002] Previously, as a rotating device, there was a so-called eccentric oscillating type speed reduction device.

[0003] This rotating device includes: an internal gear; two gear carriers rotatably supported on the internal gear and arranged opposite to each other in the direction of the rotation axis; a crankshaft rotatably supported on the gear carriers; and an external gear disposed between the gear carriers and meshing with the internal gear. The crankshaft has a journal (shaft support portion) supported on the gear carriers and an eccentric portion eccentric relative to the center of rotation.

[0004] The external gear is rotatably supported on the eccentric part. Therefore, the external gear oscillates and rotates while meshing with the internal gear.

[0005] Bearings used to rotatably support the crankshaft on the gear carrier, and bearings used to rotatably support the external gear on the eccentric part, such as rolling bearings.

[0006] To improve the driving efficiency of such rotating devices, various techniques have been proposed for uniformly distributing lubricant within the rotating device. For example, a technique has been disclosed in which grooves for guiding lubricant are formed in the eccentric portion (see, for example, Patent Document 1).

[0007] According to this technology, even when the rolling bearings located on the journal and eccentric portion are arranged axially without clearance, lubricant can be guided into the interior of the rolling bearing through the groove. Therefore, insufficient lubrication in the eccentric portion can be improved.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2024-86064 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] However, in the aforementioned prior art, the crankshaft needs to undergo machining to improve insufficient lubrication of the eccentric portion. Therefore, there is a problem of requiring crankshaft design changes, which leads to a decrease in the productivity of the rotating device.

[0013] The present invention provides a rotating device that does not require changes to the crankshaft design, thereby not degrading productivity, and enables lubricant to be distributed to the desired parts.

[0014] Solution for solving the problem

[0015] (1) A rotating device according to a technical solution of the present invention comprises: a first member and a second member that rotate relative to each other; a first bearing disposed on the first member; a second bearing disposed on the second member; and a crankshaft having a journal and an eccentric portion eccentric relative to the axis of the journal. The journal and the eccentric portion are arranged in the direction of the axis. The journal is rotatably supported on the first member by means of the first bearing. The eccentric portion supports the second member for rotation by means of the second bearing. The first bearing comprises: a plurality of first rolling elements arranged in the circumferential direction of the journal and rolling about the journal; and a first retainer holding the plurality of first rolling elements. The second bearing comprises: a plurality of second rolling elements arranged in the circumferential direction of the eccentric portion and rolling about the eccentric portion; and a second retainer holding the plurality of second rolling elements. The first retainer comprises: two first rings arranged opposite each other in the direction of the axis, spaced apart from the first rolling elements; and a plurality of first columns connecting the two first rings and disposed between adjacent first rolling elements in the circumferential direction. The second retainer includes: two second rings disposed opposite each other in the direction of the axis, spaced apart from the second rolling elements; and a plurality of second columns connecting the two second rings and disposed between adjacent second rolling elements in the circumferential direction. A gap is locally formed between adjacent first and second rings in the direction of the axis.

[0016] With this configuration, even if the first and second bearings are arranged axially, lubricant can be guided into the interior of each bearing from the gap between the first and second rings. Therefore, without requiring changes to the crankshaft design and thus without degrading productivity, lubricant can be distributed throughout the interior of the rotating device.

[0017] (2) In the above structure, the overlapping range of the first ring and the second ring may be a local part of the first ring and the second ring respectively.

[0018] (3) In the above structure, when viewed from the direction of the axis, the overlap between the first ring and the second ring is more than 180° and less than 360° with the axis as the center.

[0019] (4) In the above structure, it is also possible that when the outer diameter of the first ring is defined as Do1, the inner diameter of the second ring is defined as Di2, and the eccentricity of the eccentric part relative to the axis is defined as E, the outer diameter Do1, the inner diameter Di2 and the eccentricity E satisfy Di2 / 2>Do1 / 2-2×E.

[0020] (5) In the above structure, it may also have: a first ring outer chamfer portion formed on the outer periphery of the first ring; and a second ring inner chamfer portion formed on the outer side of the axis direction in the inner periphery of the second ring. Alternatively, when the outer diameter of the first ring is defined as Do1, the inner diameter of the second ring is defined as Di2, the eccentricity of the eccentric portion relative to the axis is defined as E, the radial width between the outer periphery of the first ring and the radial inner edge of the first ring outer chamfer portion when viewed from the direction of the axis is defined as Wo1, and the radial width between the inner periphery of the second ring and the radial outer edge of the second ring inner chamfer portion when viewed from the direction of the axis is defined as Wi2, the outer diameter Do1, the inner diameter Di2, the eccentricity E, and the widths Wo1 and Wi2 satisfy (Di2 / 2+Wi2)>(Do1 / 2-Wo1)-E.

[0021] (6) Another rotating device according to the present invention includes: a first member and a second member that rotate relative to each other; a first bearing disposed on the first member; a second bearing disposed on the second member; and a crankshaft having a journal and two eccentric portions eccentric to the axis of the journal. The two eccentric portions are arranged in the direction of the axis and staggered by 180° phase. The journal is rotatably supported on the first member by means of the first bearing. The eccentric portions support the second member for rotational rotation by means of the second bearing. The second bearing has: a plurality of second rolling elements arranged in the circumferential direction of the eccentric portions and rolling about the eccentric portions; and a second retainer that retains the plurality of second rolling elements. The second retainer includes: two second rings arranged opposite each other in the direction of the axis, spaced apart from the second rolling elements; and a plurality of second columns connecting the two second rings and disposed between adjacent second rolling elements in the circumferential direction. A gap is partially formed between two adjacent second rings in the direction of the axis in each of the two second bearings.

[0022] With this configuration, even if the two second bearings are arranged axially, lubricant can be guided from the gap between the axially adjacent second bearings into the interior of each second bearing. Therefore, without requiring changes to the crankshaft design and thus without degrading productivity, lubricant can be distributed throughout the interior of the rotating device.

[0023] (7) In the above structure, the gaps may also be formed on both sides of the radial direction centered on the axis.

[0024] (8) In the above structure, it is also possible that when the inner diameter of the second ring is defined as Di2, the outer diameter of the second ring is defined as Do2, and the eccentricity of the eccentric part relative to the axis is defined as E, the inner diameter Di2, the outer diameter Do2, and the eccentricity E satisfy Di2 / 2>Do2 / 2-2×E.

[0025] (9) In the above structure, it may also have: an inner chamfer portion of the second ring, which is formed on the outer side of the direction of the axis in the inner circumference of the second ring; and an outer chamfer portion of the second ring, which is formed on the outer circumference of the second ring. Alternatively, when the inner diameter of the second ring is defined as Di2, the outer diameter of the second ring is defined as Do2, the eccentricity of the eccentric portion relative to the axis is defined as E, the radial width between the inner circumference of the second ring and the radial outer edge of the inner chamfer portion of the second ring when viewed from the direction of the axis is defined as Wi2, and the radial width between the outer circumference of the second ring and the radial inner edge of the outer chamfer portion of the second ring when viewed from the direction of the axis is defined as Wo2, the inner diameter Di2, the outer diameter Do2, the eccentricity E, and the widths Wi2 and Wo2 satisfy (Di2+Wi2)>(Do2-Wo2)-E.

[0026] (10) The above structure may also include: a cylindrical housing having an internal gear; two gear carriers rotatably supported on the radially inner side of the housing and arranged in the direction of the axis; and an external gear disposed between the two gear carriers and meshing with the internal gear. Alternatively, the first component may include the two gear carriers, and the second component may include the external gear.

[0027] The effects of the invention

[0028] The rotating device according to the invention does not require changes to the crankshaft design, thus avoiding a deterioration in productivity, and enables lubricant to be distributed throughout the interior. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view of the deceleration device in an embodiment of the present invention.

[0030] Figure 2 yes Figure 1 Enlarged view of Part II.

[0031] Figure 3 yes Figure 2 Enlarged view of Part III.

[0032] Figure 4 This is a top view of the journal ring and eccentric ring in the embodiment of the present invention, viewed from the outside along the axial direction.

[0033] Figure 5 This is a top view of the two eccentric rings in an embodiment of the present invention, viewed from the axial direction.

[0034] Figure 6 This is a top view of the journal ring and eccentric ring in a modified embodiment of the present invention, viewed from the outside along the axial direction.

[0035] Figure 7 This is a top view of two eccentric rings in a modified embodiment of the present invention, viewed from the axial direction.

[0036] Explanation of reference numerals in the attached figures

[0037] 1. Reduction gear (rotating device); 2. Housing; 3. Gear carrier (first component); 7. Base plate (gear carrier, first component); 8. End plate (gear carrier, first component); 13. Crankshaft; 13a. First eccentric portion (eccentric portion); 13b. Second eccentric portion (eccentric portion); 13d. Journal shaft; 15. First external gear (external gear, second component); 16. Second external gear (external gear, second component); 18. Journal shaft bearing (first bearing); 19. Eccentric bearing (second bearing); 33. Eccentric rolling element (second rolling element); 34. Eccentric retainer (second retainer); 63. Journal shaft rolling element (first rolling element); 64. Journal shaft retainer (first retainer); 65. Journal shaft ring (first ring) ; 66. Journal column portion (first column portion); 75. Eccentric ring (second ring); 76. Eccentric column portion (second column portion); Di2. Inner diameter of eccentric ring (inner diameter of second ring); Do1. Outer diameter of journal ring (outer diameter of first ring); Do2. Outer diameter of eccentric ring (outer diameter of second ring); E. Eccentricity; G1. First clearance (gap); G2. Second clearance (gap); Wi2. Width of eccentric inner chamfer portion (radial width between the inner chamfer portion of the second ring and the radial outer edge); Wo1. Width of journal outer chamfer portion (radial width between the outer chamfer portion of the first ring and the radial inner edge); Wo2. Width of eccentric outer chamfer portion (radial width between the outer chamfer portion of the second ring and the radial inner edge). Detailed Implementation

[0038] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0039] <Speeding device>

[0040] Figure 1 This is a cross-sectional view of the speed reduction device 1, which is a rotating device.

[0041] like Figure 1As shown, the reduction gear 1, for example, reduces the rotational speed of an electric motor (not shown) and outputs a speed reduction. The reduction gear 1 is a so-called eccentric oscillating type reduction gear. The reduction gear 1 includes a cylindrical housing 2, a gear carrier 3 rotatably disposed on the radial inner side of the housing 2, and a reduction mechanism 4 connected to the gear carrier 3. The central axis of the housing 2 is aligned with the rotational axis of the gear carrier 3.

[0042] In the following description, the common name for these central axes and axes of rotation is defined as the first axis of rotation A1. The direction parallel to the first axis of rotation A1 is defined as the axial direction. The direction of rotation of the gear carrier 3 is defined as the circumferential direction. The radial direction of the housing 2, which is orthogonal to the axial and circumferential directions, is simply defined as the radial direction.

[0043] <Shell>

[0044] An outer flange 2a extending radially outward is integrally formed on the outer peripheral surface of the housing 2. A plurality of bolt holes 2b (not shown) are formed in the outer flange 2a for inserting bolts. The bolt holes 2b are arranged at equal intervals in the circumferential direction. Bolts (not shown) are inserted into these bolt holes 2b, for example, to fasten bolts to the arm of an industrial robot, thereby securing the reduction gear 1.

[0045] Multiple pin grooves 2c are formed along the axial direction on the inner circumferential surface of the housing 2. The pin grooves 2c are arranged at equal intervals in the circumferential direction. An internal toothed pin 5 is embedded in each pin groove 2c. The internal toothed 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.

[0046] On the inner circumferential surface of the housing 2, main bearings 6 are respectively provided on both sides in the axial direction. The gear carrier 3 is rotatably supported on the housing 2 by means of the main bearings 6. The main bearings 6 are, for example, tapered roller bearings.

[0047] <Gear Carrier>

[0048] The gear carrier 3 includes a circular plate-shaped base plate portion 7 and an end plate portion 8 arranged opposite each other in the axial direction, and three column portions 9 formed in such a way that they protrude from the base plate portion 7 toward the end plate portion 8.

[0049] Each column portion 9 is arranged at equal intervals in the circumferential direction. An end plate portion 8 is disposed on the top end 9a of the column portion 9 in such a way that it contacts the top end 9a of the column portion 9. The end plate portion 8 is combined with the base plate portion 7 by fixing it to the column portion 9 with bolts 10. When the base plate portion 7 and the end plate portion 8 are combined, a space with a certain width in the axial direction is formed between the base plate portion 7 and the end plate portion 8.

[0050] A pin hole 12a is formed in the column portion 9, located radially inward of the bolt 10. A pin 11 is inserted or pressed 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 pressed into the pin hole 12b provided in the end plate portion 8.

[0051] The outer peripheral surfaces of the base plate 7 and the end plate 8 are rotatably supported on the housing 2 by corresponding main bearings 6. Shaft insertion holes 7a and 8a are formed at the radial center of the base plate 7 and the radial center of the end plate 8, respectively. The two shaft insertion holes 7a and 8a are arranged coaxially.

[0052] On the side 7c of the base plate portion 7 facing the end plate portion 8, three crankshaft insertion recesses 7b are formed between adjacent pillar portions 9 in the circumferential direction. The crankshaft insertion recesses 7b are circular when viewed from the axial direction. A through hole 7d is formed at the bottom of the crankshaft insertion recesses 7b. The through hole 7d and the crankshaft insertion recesses 7b are arranged coaxially.

[0053] In the end plate portion 8, three crankshaft insertion holes 8b are formed coaxially with each crankshaft insertion recess 7b. Therefore, the central axis A2 of the crankshaft insertion recesses 7b and crankshaft insertion holes 8b, which are axially opposite, is parallel to the first rotation axis A1. Journal bearings (an example of the first bearing in the claim) 18 are respectively provided in these crankshaft insertion recesses 7b and crankshaft insertion holes 8b. The journal bearings 18 are restricted from axial movement by corresponding locating rings 25 and 26. Details regarding the journal bearings 18 will be described later.

[0054] <Speed ​​reduction mechanism>

[0055] The reduction mechanism 4, for example, causes the gear carrier 3 to rotate at a speed reduced by a certain ratio relative to the speed of the motor shaft of the electric motor (not shown).

[0056] The reduction mechanism 4 includes: three crankshafts 13 inserted into each crankshaft insertion recess 7b and each crankshaft insertion hole 8b; a transmission spur gear 14 disposed at the axial end of each crankshaft 13; and two external gears 15 and 16 (first external gear 15 and second external gear 16) disposed between the base plate portion 7 and the end plate portion 8.

[0057] The transmission spur gear 14 meshes with a motor shaft (not shown). Thus, the rotation of the electric motor is transmitted to the transmission spur gear 14, causing the transmission spur gear 14 to rotate.

[0058] Each crankshaft 13 is rotatably supported on the gear carrier 3 (base plate portion 7 and end plate portion 8) by means of each journal bearing 18. The crankshaft 13 has a shaft body 13c that rotates around the central axis A2, a first eccentric portion 13a and a second eccentric portion 13b formed at the center of the shaft body 13c in the axial direction, and journals 13d formed on both sides of the axial direction apart from each eccentric portion 13a, 13b.

[0059] The journal 13d has a larger diameter than the shaft body 13c. The journal 13d and the shaft body 13c are mounted coaxially. The journal 13d is rotatably supported on the gear carrier 3 (base plate 7 and end plate 8) by means of a journal bearing 18.

[0060] In the following description, the two sides of the shaft body 13c along the axial direction are defined as the outer sides of the axial direction. The central side of the shaft body 13c, where the eccentric portions 13a and 13b are arranged, is simply defined as the central side of the axial direction.

[0061] The outer end face of the journal 13d located on the base plate 7 side abuts axially against the positioning ring 25 provided in the crankshaft insertion recess 7b. The outer end face of the journal 13d located on the end plate 8 side abuts axially against the positioning ring 26 provided in the crankshaft insertion hole 8b. Thus, the crankshaft 13 is positioned axially.

[0062] The crankshaft body 13c and the transmission spur gear 14 are arranged coaxially and integrated. Therefore, the crankshaft 13 and the transmission spur gear 14 rotate integrally about the central axis A2. Hereinafter, the central axis A2 is defined as the second rotation axis A2 of the crankshaft 13. The second rotation axis A2 is an example of the axis in the claims.

[0063] The shaft diameters of the first eccentric portion 13a and the second eccentric portion 13b are equal to the shaft diameter of the journal bearing 13d. The first eccentric portion 13a and the second eccentric portion 13b are eccentric relative to the second rotation axis A2. The first eccentric portion 13a and the second eccentric portion 13b are axially adjacent between the two journal bearings 18. The first eccentric portion 13a and the second eccentric portion 13b are arranged with a 180° phase angle offset.

[0064] Each eccentric portion 13a, 13b is provided with an eccentric bearing (an example of the second bearing in the claim) 19. The two eccentric bearings 19 are arranged axially and are also arranged axially with the journal bearing 18. The axial arrangement of the bearings 18, 19 restricts the axial movement of each bearing 18, 19.

[0065] The first external gear 15 and the second external gear 16 are rotatably supported on each crankshaft 13 by means of an eccentric bearing 19. Details of the eccentric bearing 19 will be described later.

[0066] The first external gear 15 and the second external gear 16 are disposed 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 and rotate with the rotation of the crankshaft 13. Through holes 15a and 16a are formed in the first external gear 15 and the second external gear 16 for the eccentric bearing 19 to be provided. Thus, when the first eccentric portion 13a and the second eccentric portion 13b oscillate and rotate due to the rotation of the crankshaft 13, the first external gear 15 and the second external gear 16 oscillate and rotate with the aid of the eccentric bearing 19.

[0067] The first external gear 15 and the second external gear 16 are respectively provided with openings 15b and 16b to avoid interference with the column portion 9. Shaft insertion holes 15c and 16c are formed at the radial center of the first external gear 15 and the second external gear 16. External teeth 15d and 16d are respectively formed on the outer periphery of the first external gear 15 and the outer periphery of the second external gear 16. The number of teeth on each external tooth 15d and 16d is, for example, one less than the number of internal toothed pins 5 in the housing 2.

[0068] <Journal bearings and eccentric bearings>

[0069] Figure 2 yes Figure 1 Enlarged view of Part II. Figure 3 yes Figure 2 Enlarged view of Part III.

[0070] like Figures 1 to 3 As shown, the journal bearing 18 and the eccentric bearing 19 are needle roller bearings.

[0071] The two journal bearings 18 include: an annular inner journal ring 61, which is integrated with the journal 13d of the crankshaft 13; an annular outer journal ring 62, which is integrated with the base plate 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, which are disposed between the inner journal ring 61 and the outer journal ring 62; and a journal retainer (an example of the first retainer in the claim) 64, which retains the journal rolling elements 63. The journal rolling elements 63 are needle rollers arranged parallel to the axial direction.

[0072] The journal rolling elements 63 are arranged circumferentially on the inner journal ring 61 and the outer journal ring 62. Therefore, the journal rolling elements 63 roll about the journal neck 13d.

[0073] The journal retainer 64 includes two annular journal rings (an example of the first ring in the claim) 65 arranged axially opposite to each other with respect to the journal rolling elements 63, and a journal post portion (the first post portion in the claim) 66 connecting the two journal rings 65. The two journal rings 65 and the journal post portion 66 are integrally formed.

[0074] The journal post portion 66 is formed to extend axially and is arranged at equal intervals in the circumferential direction. Each journal rolling element 63 is respectively housed in a plurality of journal groove portions 67 divided by each journal post portion 66 and two journal rings 65. Thus, the journal rolling element 63 is held by the journal retainer 64.

[0075] The two eccentric bearings 19 include: 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 disposed between the eccentric inner ring 31 and the eccentric outer ring 32; and an eccentric retainer (an example of the second retainer 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.

[0076] The eccentric rolling elements 33 are arranged circumferentially on the eccentric inner ring 31 and the eccentric outer ring 32. Therefore, the eccentric rolling elements 33 roll around the eccentric portions 13a and 13b.

[0077] The eccentric retainer 34 includes two annular eccentric rings (an example of the second ring in the claim) 75 arranged axially opposite each other with the eccentric rolling element 33 between them, and an eccentric column portion (the second column portion in the claim) 76 connecting the two eccentric rings 75. The two eccentric rings 75 and the eccentric column portion 76 are integrally formed.

[0078] The eccentric column portions 76 are formed to extend axially and are arranged at equal intervals in the circumferential direction. Each eccentric rolling element 33 is respectively housed in a plurality of eccentric grooves 77 divided by each eccentric column portion 76 and two eccentric rings 75. Thus, the eccentric rolling elements 33 are held by the eccentric retainer 34.

[0079] Each of these retainers 34 and 64 is formed of resin. For example, a nylon resin containing glass can be used as the resin. However, it is not limited to this; various resins can be used.

[0080] In addition, cages 34 and 64 are not limited to resin, but can also be made of metal.

[0081] <Regarding the construction of the gaps between the retainers>

[0082] A first gap G1 is locally formed between adjacent journal retainers 64 and eccentric retainers 34 in the axial direction. A second gap G2 is locally formed between two adjacent eccentric retainers 34 in the axial direction. The structure forming these gaps G1 and G2 will be described in detail below.

[0083] First, let's explain the first gap G1.

[0084] Figure 4This is a top view of the journal ring 65 and eccentric ring 75 viewed from the outer side along the axial direction. (Example) Figure 4 As shown, the journal ring 65 and the eccentric ring 75 are in partial contact (refer to...). Figure 4 The shaded area in the image shows the first region Ar1. Therefore, the journal ring 65 and the eccentric ring 75 only partially overlap when viewed from the axial direction.

[0085] As a result, a first gap G1 is formed at the part where the journal ring 65 and the eccentric ring 75 do not contact when viewed from the axial direction.

[0086] When viewed from the axial direction, the range θ1 of the first region Ar1 is greater than 180° and less than 360° (hereafter, this condition is defined as condition 1). The range θ1 refers to the angle between the two first straight lines L1 that connect the second axis of rotation A2 to the two ends of the first region Ar1 in the circumferential direction.

[0087] To satisfy condition 1, more specifically, the specified dimensions are determined as follows. That is, as... Figure 2 As shown, when the outer diameter of journal ring 65 is defined as Do1, the inner diameter of eccentric ring 75 is defined as Di2, and the eccentricity of each eccentric part 13a, 13b relative to the second rotation axis A2 is defined as E, the outer diameter Do1 of journal ring 65, the inner diameter Di2 of eccentric ring 75 and the eccentricity E satisfy the following equation (1).

[0088] Di2 / 2>Do1 / 2-2×E……Equation (1)

[0089] To satisfy condition 1, it can also be configured as follows.

[0090] That is, such as Figure 3 As shown, an outer flat chamfered portion 65a (an example of the outer chamfered portion of the first ring in the claim) is formed on the outer periphery of the journal ring 65. An eccentric inner flat chamfered portion 75a is formed on the outer corner of the axial direction of the inner periphery of the eccentric ring 75, that is, on the corner of the journal ring 65 side. Each flat chamfered portion 65a, 75a is formed flat.

[0091] Based on this structure, when the radial width of the outer flat chamfer 65a of the journal (hereinafter referred to as the width of the outer flat chamfer 65a) is defined as Wo1 and the radial width of the eccentric inner flat chamfer 75a (hereinafter referred to as the width of the eccentric inner flat chamfer 75a) is defined as Wi2, 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 outer flat chamfer 65a and the width Wi2 of the eccentric inner flat chamfer 75a satisfy the following equation (2).

[0092] (Di2 / 2+Wi2)>(Do1 / 2-Wo1)-E...Formula (2)

[0093] More specifically, the width Wo1 of the outer flat chamfer 65a of the journal corresponds to the radial width between the outer periphery of the journal ring 65 and the inner periphery of the outer flat chamfer 65a when viewed axially. More specifically, the width Wi2 of the eccentric inner flat chamfer 75a corresponds to the radial width between the inner periphery of the eccentric ring 75 and the radially outer edge of the eccentric inner flat chamfer 75a when viewed axially.

[0094] Furthermore, if the above formula (1) is satisfied, the outer flat chamfer 65a and the eccentric inner flat chamfer 75a of the journal are not necessary structures.

[0095] Next, the second gap G2 will be explained.

[0096] Figure 5 This is a top view of the two eccentric rings 75 viewed from the axial direction.

[0097] like Figure 5 As shown, two eccentric rings 75 have second gaps G2 formed on both sides of the radial direction centered on the second rotation axis A2. Therefore, the two eccentric rings 75 have local contact on both sides of the radial direction centered on the second rotation axis A2. Figure 5 The second region Ar2 is shown in the shaded area. That is, when viewed from the axial direction, the two eccentric rings 75 overlap only radially on both sides centered on the second axis of rotation A2.

[0098] To satisfy the condition for forming the second gap G2 (defined as condition 2), more specifically, the specified dimensions are determined as follows. That is, as Figure 2 As shown, when the outer diameter of the eccentric ring 75 is defined as Do2, the outer diameter Do2 of the eccentric ring 75, the inner diameter Di2 of the eccentric ring 75, and the eccentricity E satisfy the following equation (3).

[0099] Di2 / 2>Do2 / 2-2×E……Equation (3)

[0100] To satisfy condition 2, it can also be configured as follows.

[0101] That is, such as Figure 3 As shown, an eccentric inner flat chamfered portion 75a is formed in the eccentric ring 75, and an eccentric outer flat chamfered portion 75b is formed on the outer periphery of the eccentric ring 75. The eccentric outer flat chamfered portion 75b also has a flat topography similar to the eccentric inner flat chamfered portion 75a.

[0102] Based on this structure, when the radial width of the eccentric outer flat chamfer 75b viewed from the axial direction (hereinafter referred to as the width of the eccentric outer flat chamfer 75b) is defined as Wo2, the outer diameter Do2 of the eccentric ring 75, the inner diameter Di2 of the eccentric ring 75, the eccentricity E, the width Wi2 of the eccentric inner flat chamfer 75a, and the width Wo2 of the eccentric outer flat chamfer 75b satisfy the following equation (4).

[0103] (Di2+Wi2)>(Do2-Wo2)-E...Formula (4)

[0104] More specifically, the width Wo2 of the eccentric outer flat chamfer 75b is equivalent to the radial width between the outer periphery of the eccentric ring 75 and the radial inner edge of the eccentric outer flat chamfer 75b when viewed from the axial direction.

[0105] Furthermore, if the above formula (3) is satisfied, the eccentric inner flat chamfer 75a and the eccentric outer flat chamfer 75b are not necessary structures.

[0106] <Operation of the deceleration device>

[0107] Next, the operation of the deceleration device 1 will be explained.

[0108] An electric motor (not shown) rotates the transmission spur gear 14 and crankshaft 13 as a single unit. This causes the first external gear 15 and the second external gear 16 to oscillate and rotate. As this oscillating rotation occurs, a portion of the external teeth 15d and 16d of each external gear 15 and 16 meshes with the internal toothed pins 5 of the housing 2. The number of teeth on each external tooth 15d and 16d is, for example, one less than the number of internal toothed pins 5. Therefore, each external gear 15 and 16 rotates in a manner where the meshing portions of each external tooth 15d and 16d relative to the internal toothed pins 5 (housing 2) are sequentially staggered circumferentially. This rotation is decelerated relative to the rotation of the crankshaft 13.

[0109] As the external gears 15 and 16 rotate, each crankshaft 13 also rotates on its own axis about the second rotation axis A2 and revolves around the first rotation axis A1. Each crankshaft 13 is rotatably supported on the gear carrier 3 (base plate portion 7 and end plate portion 8). Therefore, the gear carrier 3 rotates along with the revolution of each crankshaft 13.

[0110] As a result, the reduction gear 1 slows down the rotation of the electric motor (motor shaft), which is not shown, and outputs the speed from the gear carrier 3. Assuming that the gear carrier 3 is fixed to the arm of an industrial robot, the reduction gear 1 can slow down the rotation of the electric motor and output the speed from the housing 2.

[0111] In addition, to improve the driving efficiency of the reduction gear 1, each bearing 18 and 19 mounted on the crankshaft 13 is filled with sufficient lubricant. When the crankshaft 13 rotates, centrifugal force acts on the lubricant. As a result, the lubricant tends to move towards the outer periphery of each bearing 18 and 19.

[0112] Furthermore, when the journal retainers 64 arranged axially are in contact with the eccentric retainers 34, or when the two eccentric retainers 34 are in contact with each other, the gaps between the retainers 64 and 34 are easily filled. Therefore, the lubricant that is close to the outer periphery of each bearing 18 and 19 is difficult to flow back into each bearing 18 and 19.

[0113] However, in the reduction gear 1 according to this embodiment, each retainer 64, 34 has a first gap G1 partially formed 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. Thus, lubricant can be distributed throughout the interior of the reduction gear 1.

[0114] To guide the lubricant into the interior of each bearing 18, 19, neither additional machining of the crankshaft 13 nor design changes to the crankshaft 13 are required. Therefore, it is possible to prevent the productivity of the reduction gear 1 from deteriorating.

[0115] The overlap between journal ring 65 and eccentric ring 75 is a localized area of ​​each of journal ring 65 and eccentric ring 75. With this configuration, a first gap G1 can be easily formed between journal ring 65 and eccentric ring 75.

[0116] The overlap between journal ring 65 and eccentric ring 75 satisfies condition 1. Therefore, when journal ring 65 and eccentric ring 75 are in contact, it is possible to prevent the load applied to each ring 65 and 75 from being biased to one side and causing each ring 65 and 75 to tilt.

[0117] To satisfy condition 1, journal ring 65 and eccentric ring 75 satisfy the above equation (1). Therefore, there is no need to make journal ring 65 and eccentric ring 75 into complex shapes, and journal ring 65 and eccentric ring 75 can be easily formed.

[0118] As another method to satisfy condition 1, an outer flat chamfered portion 65a is formed in the journal ring 65, and an inner flat chamfered portion 75a is formed in the eccentric ring 75. Based on this, the above equation (2) is satisfied. In this case, it is not necessary to make the journal ring 65 and the eccentric ring 75 into complex shapes. Therefore, the journal ring 65 and the eccentric ring 75 can be easily formed.

[0119] Furthermore, a second gap G2 is partially formed between the two eccentric retainers 34 in the deceleration device 1 of this embodiment. 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 deceleration device 1.

[0120] To guide the lubricant into the interior of the eccentric bearing 19, neither additional machining of the crankshaft 13 nor design changes to the crankshaft 13 are required. Therefore, it is possible to prevent the deterioration of the productivity of the reduction gear 1.

[0121] The second clearance G2 is formed on both radial sides of the crankshaft 13 with the second rotation axis A2 as the center. Therefore, it is possible to guide the lubricant into the interior of the eccentric bearing 19 in a well balanced manner in the circumferential direction.

[0122] Furthermore, the two eccentric bearings 19 can be made to contact equally from the left and right when viewed from the axial direction. Therefore, it is possible to prevent unilateral collisions that could cause the eccentric bearings 19 to tilt when they are in contact with each other.

[0123] In order to satisfy condition 2 for forming the second gap G2, the eccentric ring 75 satisfies the above equation (3). Therefore, it is not necessary to make the eccentric ring 75 a complex shape, and it can be easily formed.

[0124] As another method to satisfy condition 2, an eccentric inner flat chamfered portion 75a and an eccentric outer flat chamfered portion 75b are formed in the eccentric ring 75. Based on this, the above equation (4) is satisfied. In this case, it is not necessary to make the eccentric ring 75 a complex shape, and it can be easily formed.

[0125] The reduction gear 1 is a so-called oscillating gear reduction gear. Such a reduction gear has less internal clearance, so the structure of each retainer 34, 64 as described above is preferred.

[0126] [Variation Example]

[0127] In the above embodiments, the cases in which the above equations (1) and (2) are satisfied in order to locally form a first gap G1 between the journal ring 65 and the eccentric ring 75 are described. Furthermore, the cases in which the above equations (3) and (4) are satisfied in order to locally form a second gap G2 between the two eccentric rings 75 are described.

[0128] However, it is not limited to this; the journal ring 65 and the eccentric ring 75 can also be constructed with a first gap G1 and a second gap G2. A specific example will be described below.

[0129] Figure 6 This is a top view of the journal ring 65 and eccentric ring 75 in the modified example, viewed from the outside along the axial direction. Figure 6 Corresponding to Figure 4 . Figure 7 This is a top view of the two eccentric rings 75 in the deformed example, viewed from the axial direction. Figure 7 Corresponding to Figure 5 .

[0130] like Figure 6 , Figure 7 As shown, a plurality of recesses 75c are formed on the inner circumference of the eccentric ring 75 in the modified example. The plurality of recesses 75c are arranged at equal intervals in the circumferential direction. The plurality of recesses 75c are formed in a semi-circular shape. However, it is not limited to this, and the shape of the recesses 75c can be arbitrarily determined, for example, to be a triangular shape, a quadrilateral shape, etc.

[0131] like Figure 6 As shown, by forming a recess 75c, the journal ring 65 and the eccentric ring 75 are in partial contact (see reference). Figure 6 The shaded area (Ar1) is shown in the diagram. Therefore, the journal ring 65 and the eccentric ring 75 only partially overlap when viewed axially. That is, when viewed axially, the portions of the journal ring 65 and the eccentric ring 75 with the recesses 75c are not in contact. A first gap G1 is formed at this non-contact portion.

[0132] like Figure 7 As shown, by forming a recess 75c, the two eccentric rings 75 respectively form a second gap G2 on both sides of the radial direction centered on the second rotation axis A2. Therefore, the two eccentric rings 75 partially contact each other on both sides of the radial direction centered on the second rotation axis A2. Figure 7 The second region Ar2 is shown in the shaded area. That is, when viewed from the axial direction, the portions of the two eccentric rings 75 with the recesses 75c are partially not in contact. A second gap G2 is formed at this non-contact portion.

[0133] Therefore, the modified examples described above achieve the same effect as the embodiments described above.

[0134] [Other variations]

[0135] This invention is not limited to the embodiments described above, but includes embodiments in which various modifications are made to the embodiments described above without departing from the spirit of this invention.

[0136] For example, in the above embodiment, the eccentric swing type speed reduction device 1 is described as an example of the rotating device, and the case where the speed reduction device 1 is provided with a journal bearing 18 and an eccentric bearing 19 is described.

[0137] However, it is not limited to this. In various rotating devices that use crankshaft 13 and crankshaft 13 bearings, the bearing can adopt the structure of journal bearing 18 and eccentric bearing 19.

[0138] Alternatively, the inner ring 61 of the journal may not be integrally formed on the journal 13d, or the eccentric inner ring 31 may not be integrally formed on the eccentric portions 13a and 13b. Similarly, the outer ring 62 of the journal may not be integrally formed on the gear carrier 3 (base plate portion 7, end plate portion 8), or the eccentric outer ring 32 may not be integrally formed on the external gears 15 and 16. The journal rolling element 63 can roll around the journal 13d. The eccentric rolling element 33 can roll around the eccentric portions 13a and 13b.

[0139] In the above embodiments, the case where the journal bearing 18 and the eccentric bearing 19 are needle roller bearings has been described. However, it is not limited to this, and the structure of the journal bearing 18 and the eccentric bearing 19 can be used for various bearings having rolling elements and cages.

[0140] In the above embodiment, the case where the reduction device 1 has multiple (e.g., 3) crankshafts 13 was described as an eccentric oscillating type reduction device. However, it is not limited to this; in such a reduction device, there may also be only one crankshaft 13. In this case, the crankshaft 13 is arranged coaxially with the first rotation axis A1.

[0141] In the above embodiment, the reduction gear 1 was described with two external gears 15 and 16. However, it is not limited to this; having at least one external gear is sufficient. It may also have three or more external gears. The number of eccentric portions can be varied depending on the number of external gears. With such a configuration, it can still function as an eccentric oscillating type reduction gear.

[0142] In the above embodiment, the case where the inner journal ring 61 of the journal bearing 18 and the journal 13d of the crankshaft 13 are integrated has been described. However, it is not limited to this, and the inner journal ring 61 may also be separately constructed from the journal 13d.

[0143] The case where the journal outer ring 62 of the journal bearing 18 is integrated with the base plate portion 7 and the end plate portion 8 has been described. However, it is not limited to this case; the journal outer ring 62 may also be separately constructed from the base plate portion 7 and the end plate portion 8.

[0144] In the embodiments disclosed in this specification, a component composed of multiple objects can be integrated into one object; conversely, a component composed of a single object can be divided into multiple objects. Whether integrated or not, it is acceptable as long as the configuration achieves the purpose of the invention.

Claims

1. A rotating device, wherein The rotating device has the following features: The first and second components rotate relative to each other; A first bearing is disposed on the first component; A second bearing, disposed on the second component; and A crankshaft having a journal and an eccentric portion offset from the axis of the journal. The journal and the eccentric portion are arranged in the direction of the axis. The journal is rotatably supported on the first component by means of the first bearing. The eccentric portion supports the second component for free rotation via the second bearing. The first bearing comprises: A plurality of first rolling elements are arranged circumferentially on the journal and roll about the journal; and A first retainer holds the plurality of first rolling elements. The second bearing comprises: A plurality of second rolling elements are arranged circumferentially around the eccentric portion and roll about the eccentric portion; and A second retainer holds the plurality of second rolling elements. The first holder includes: Two first rings are arranged opposite each other in the direction of the axis, separated by the first rolling element; and A plurality of first pillars connect the two first rings and are disposed between the first rolling elements that are adjacent in the circumferential direction. The second holder includes: Two second rings are arranged opposite each other in the direction of the axis, spaced apart from the second rolling element; and A plurality of second columns connect the two second rings and are disposed between adjacent second rolling elements in the circumferential direction. A gap is locally formed between the first ring and the second ring that are adjacent to each other in the direction of the axis.

2. The rotating device according to claim 1, wherein, The overlapping area between the first ring and the second ring is a local portion of each of the first ring and the second ring.

3. The rotating device according to claim 2, wherein, When viewed from the direction of the axis, the overlap between the first ring and the second ring is more than 180° and less than 360° centered on the axis.

4. The rotating device according to any one of claims 1-3, wherein, When the outer diameter of the first ring is defined as Do1, the inner diameter of the second ring as Di2, and the eccentricity of the eccentric portion relative to the axis is defined as E, the outer diameter Do1, the inner diameter Di2, and the eccentricity E satisfy the following conditions: Di2 / 2>Do1 / 2-2×E.

5. The rotating device according to any one of claims 1-3, wherein, The rotating device has: The outer chamfer portion of the first ring is formed on the outer periphery of the first ring; and The inner chamfer of the second ring is formed on the outer side of the axis in the inner circumference of the second ring. When the outer diameter of the first ring is defined as Do1, the inner diameter of the second ring as Di2, the eccentricity of the eccentric portion relative to the axis is defined as E, the radial width between the outer periphery of the first ring and the radial inner edge of the outer chamfer of the first ring (viewed from the direction of the axis) is defined as Wo1, and the radial width between the inner periphery of the second ring and the radial outer edge of the inner chamfer of the second ring (viewed from the direction of the axis) is defined as Wi2, the outer diameter Do1, the inner diameter Di2, the eccentricity E, and the widths Wo1 and Wi2 satisfy the following conditions: (Di2 / 2+Wi2)>(Do1 / 2-Wo1)-E.

6. A rotating device, wherein, The rotating device has the following features: The first and second components rotate relative to each other; A first bearing is disposed on the first component; A second bearing is disposed on the second component; as well as A crankshaft having a journal and two eccentric portions offset from the axis of the journal. The two eccentric portions are arranged in the direction of the axis and are staggered by 180° in phase. The journal is rotatably supported on the first component by means of the first bearing. The eccentric portion supports the second component for free rotation via the second bearing. The second bearing comprises: A plurality of second rolling elements are arranged circumferentially around the eccentric portion and roll about the eccentric portion; and A second retainer holds the plurality of second rolling elements. The second holder includes: Two second rings are arranged opposite each other in the direction of the axis, spaced apart from the second rolling element; and A plurality of second columns connect the two second rings and are disposed between adjacent second rolling elements in the circumferential direction. A gap is locally formed between two adjacent second rings in the direction of the axis in each of the two second bearings.

7. The rotating device according to claim 6, wherein, The gaps are formed on both sides of the radial direction centered on the axis.

8. The rotating device according to claim 6 or 7, wherein, When the inner diameter of the second ring is defined as Di2, the outer diameter of the second ring is defined as Do2, and the eccentricity of the eccentric portion relative to the axis is defined as E, the inner diameter Di2, the outer diameter Do2, and the eccentricity E satisfy the following conditions: Di2 / 2>Do2 / 2-2×E.

9. The rotating device according to claim 6 or 7, wherein, The rotating device has: The inner chamfer of the second ring is formed on the outer side of the direction of the axis within the inner circumference of the second ring; and The outer chamfer of the second ring is formed on the outer periphery of the second ring. When the inner diameter of the second ring is defined as Di2, the outer diameter of the second ring as Do2, the eccentricity of the eccentric portion relative to the axis is defined as 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 when viewed from the direction of the axis is defined as 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 when viewed from the direction of the axis is defined as Wo2, The inner diameter Di2, the outer diameter Do2, the eccentricity E, and the widths Wi2 and Wo2 satisfy the following conditions: (Di2+Wi2)>(Do2-Wo2)-E.

10. The rotating device according to claim 1 or 6, wherein, The rotating device has the following features: A cylindrical shell with internal gears; Two gear carriers are rotatably supported on the radially inner side of the housing and are arranged in the direction of the axis. as well as The external gear, positioned between the two gear carriers, meshes with the internal gear. The first component includes the two gear carriers. The second component includes the external gear.

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