gear mechanism

Abstract

To maintain the state of proper connection between a main body member and a bearing housing.SOLUTION: A gear unit is provided, comprising an input shaft 30, a first input bearing 46 supporting the input shaft, a first bearing housing 44 supporting the first input bearing, a first main body member 41 to which the first bearing housing is connected, an external gear 35, and internal gears 411, 421, wherein the first bearing housing and the first main body member are fitted with each other via a fitting portion P and connected to each other by a first connection member 441, the fitting portion has a first fitting portion P1 far away from a connection portion of the first connection member and a second fitting portion P2 closer to the connection portion than the first fitting portion. The interference of the second fitting portion is larger than the interference of the first fitting portion.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gear device. [Background technology]

[0002] A conventional gear device includes an input shaft, a bearing housing that rotatably supports the input shaft via an input bearing, and a main body member that is connected to the bearing housing and fixedly supported by an external member that serves as the base, and the rotational speed of the input shaft is changed and adjusted by gears and output to a mating member. In the above gear device, the main body member is fitted and supports the bearing housing, and the main body member and the bearing housing are connected to each other by connecting members such as bolts (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-60423 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described gear device, if a load acts on the input bearing due to misalignment caused by an external load applied to the gear device or an external load when power is transmitted to the input shaft, there is a risk that minute slippage will occur on the mating surfaces of the main body member and the bearing housing or on the bolt seating surfaces, causing the bolt to loosen.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to maintain a proper connection between the body member and the bearing housing. [Means for solving the problem]

[0006] The present invention provides An input shaft; a first input bearing that supports the input shaft; a first bearing housing that supports the first input bearing; a first body member to which the first bearing housing is connected; an external gear; an internal gear; A gear train comprising: the first bearing housing is disposed on one axially lateral side of the external gear, the first bearing housing and the first body member are fitted together at a fitting portion and connected together by a first connecting member, the fitting portion has a first fitting portion that is farther from the connection portion formed by the first connection member and a second fitting portion that is closer to the connection portion than the first fitting portion, The interference of the second fitting portion is larger than the interference of the first fitting portion. Ku, Furthermore, the interference of the second fitting portion is larger than the interference of the fitting portion between a second body member and a second bearing housing, which has a second input bearing that supports the input shaft at a position different from the first input bearing and is located on the other axial side of the first bearing housing with the external gear sandwiched therebetween. It is a gear device. Another invention is: An input shaft; a first input bearing that supports the input shaft; a first bearing housing that supports the first input bearing; a first body member to which the first bearing housing is connected; an external gear; an internal gear; A gear train comprising: the first bearing housing and the first body member are fitted together at a fitting portion and connected together by a first connecting member, the fitting portion has a first fitting portion that is farther from the connection portion formed by the first connection member and a second fitting portion that is closer to the connection portion than the first fitting portion, The interference of the second fitting portion is greater than the interference of the first fitting portion, the input shaft is a vibrator shaft having a vibrator that flexibly deforms the external gear, The internal gear is a cylindrical flexible mesh gear device having a first internal gear and a second internal gear, The reduced rotation is output to a mating member via the second internal gear, and the first body member is integrated with the first internal gear, a second bearing housing connected by a second connecting member to a second body member integrated with the second internal gear; a second input bearing disposed in the second bearing housing and supporting the input shaft; The connecting force of the second connecting member is greater than the connecting force of the first connecting member, The fitting portion between the second bearing housing and the second body member has a constant interference. It is a gear device. [Effects of the Invention]

[0007] According to the present invention, it is possible to maintain a proper connection state between the main body member and the bearing housing. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an axial cross-sectional view showing a flexible mesh gear device according to an embodiment of the present invention; [Figure 2] FIG. 3 is an enlarged cross-sectional view of the periphery of a first bearing housing. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0010] [Overall configuration of a flexible mesh gear device] Fig. 1 is an axial cross-sectional view showing a flexible mesh gear device 1 according to an embodiment of the present invention. In Fig. 1, the portion above the rotation axis O1 of the flexible mesh gear device 1 is a cross-sectional view including a direction along the major axis of a vibrator 30A (described later), and the portion below the rotation axis O1 is a cross-sectional view including a direction along the minor axis of the vibrator 30A. In the following description, the direction parallel to the rotation axis O1 described below is referred to as the axial direction, the direction along the circumference centered on the rotation axis O1 is referred to as the circumferential direction, and the direction along the radius of the circumference centered on the rotation axis O1 is referred to as the radial direction.

[0011] The flexible mesh gear device 1 is, for example, a reduction gear device. The use of the flexible mesh gear device 1 is not particularly limited, and it can be used in a variety of applications. This flexible mesh gear device 1 comprises an exciter shaft 30 (input shaft), an exciter bearing 31, an external gear 35, a first internal tooth portion 411, a second internal tooth portion 421, a casing 43, a first bearing housing 44, a second bearing housing 45, a first input bearing 46, a second input bearing 47, a main bearing 48, and stopper rings 51 and 52.

[0012] The vibrator shaft 30 is a hollow cylindrical shaft that rotates around the rotation axis O1, and includes a vibrator 30A whose cross section perpendicular to the rotation axis O1 has a non-circular (e.g., elliptical) outer shape, and shaft portions 30B and 30C provided on both sides of the vibrator 30A in the axial direction. The elliptical shape does not need to be a strict geometric ellipse and includes an approximate ellipse. The elliptical shape referred to here may be an oblong shape having a major axis perpendicular to the rotation axis O1 and a minor axis perpendicular to the major axis. The shaft portions 30B and 30C are shafts whose cross section perpendicular to the rotation axis O1 has a circular outer shape. The vibrator shaft 30 may be a solid shaft.

[0013] The first internally toothed portion 411 is a first internally toothed gear having rigidity, and is configured by internal teeth provided on a part of the inner circumference of the first main body member 41. The second internally toothed portion 421 is a second internally toothed gear having rigidity, and is configured by internal teeth provided on a part of the inner circumference of the second main body member .

[0014] The first external toothed portion 32 and the second external toothed portion 33 are integrally provided side by side in the axial direction on the outer periphery of a single flexible metallic cylindrical base portion 34. The first external toothed portion 32, the second external toothed portion 33, and the base portion 34 constitute an external gear 35. The first external teeth portion 32 meshes with the first internal teeth portion 411 , and the second external teeth portion 33 meshes with the second internal teeth portion 421 .

[0015] The vibrator bearing 31 is, for example, a roller bearing, and is arranged between the vibrator 30A and a base 34 on which the first external toothed portion 32 and the second external toothed portion 33 are formed. The vibrator 30A and the first external toothed portion 32 and the second external toothed portion 33 are rotatable relative to each other via the vibrator bearing 31. The vibrator bearing 31 has an outer ring 31a fitted inside the base 34, a plurality of rolling elements (rollers) 31b, and a cage 31c that holds the plurality of rolling elements 31b. The multiple rolling elements 31b include a first group of rolling elements 31b arranged radially inward of the first external tooth portion 32 and the first internal tooth portion 411 and aligned in the circumferential direction, and a second group of rolling elements 31b arranged radially inward of the second external tooth portion 33 and the second internal tooth portion 421 and aligned in the circumferential direction. These rolling elements 31b roll with the outer periphery of the vibrator 30A as their inner rolling surface and the inner periphery of the outer ring 31a as their outer rolling surface.

[0016] The vibrator bearing 31 may have an inner ring separate from the vibrator 30A. Furthermore, the vibrator bearing 31 may not have the outer ring 31a, and the inner circumference of the base 34 may serve as the outer rolling surface. The type of rolling elements is not particularly limited, and may be balls, for example. Furthermore, the number of rows of rolling elements is not limited to two, and may be one row, or three or more rows.

[0017] The stopper ring 51 is arranged between one axial end of the external gear 35 and the vibrator bearing 31 and the first input bearing 46, and the stopper ring 52 is arranged between the other axial end of the external gear 35 and the vibrator bearing 31 and the second input bearing 47. These stopper rings 51 and 52 restrict the axial movement of the external gear 35 and the vibrator bearing 31 .

[0018] The casing 43 covers the outer peripheral side of the second body member 42. An outer ring portion of a main bearing 48 is formed on the inner peripheral portion of the casing 43, and the second body member 42 is rotatably supported via the main bearing 48. The casing 43 is connected to the first body member 41 via a connecting member 431 such as a bolt, for example.

[0019] The main bearing 48 is, for example, a cross roller bearing, and has a plurality of rolling elements arranged between an inner ring portion integrated with the second body member 42 and an outer ring portion integrated with the casing 43. Note that the main bearing 48 may also be composed of a plurality of bearings (angular contact ball bearings, tapered bearings, etc.) spaced apart in the axial direction between the second body member 42 and the casing 43. Furthermore, an oil seal 541 is provided between the casing 43 and the second body member 42, on the output side of the main bearing 48, to prevent the lubricant from leaking outward in the axial direction (toward the output side).

[0020] The first bearing housing 44 is connected to the first main body member 41 via a first connecting member 441 such as a bolt. The first bearing housing 44 covers the first external tooth portion 32 and the first internal tooth portion 411 from the axially opposite side to the output side. The first main body member 41 and the casing 43 are directly or indirectly connected to an external member.

[0021] In this embodiment, the side that is connected to a mating member 56 (for example, one of the members (driven member) of a main device in which power is transmitted between the mating member 56 and the first main body member 41, i.e., the mating member 56 is a member that rotates relative to an external member to which the first main body member 41, etc., is connected) and outputs decelerated motion to the mating member 56 is called the output side (left side in FIG. 1), and the side opposite the output side in the axial direction is called the anti-output side (right side in FIG. 1). A first input bearing 46 is disposed between the first bearing housing 44 and the shaft portion 30B of the vibrator shaft 30, and the vibrator shaft 30 is rotatably supported by the first bearing housing 44. Although a ball bearing is shown as the first input bearing 46, other radial bearings may also be used. In addition, an oil seal 542 is provided between the first bearing housing 44 and the shaft portion 30B of the vibrator shaft 30, on the anti-output side of the first input bearing 46, to prevent lubricant from leaking outward in the axial direction (anti-output side).

[0022] The second bearing housing 45 is connected to the mating member 56 and the second main body member 42 via a second connecting member (A) 561 such as a bolt, and is also connected to the second main body member 42 via a second connecting member (B) 533 such as a bolt. In other words, the second bearing housing 45 and the second main body member 42 are connected to the mating member 56 that outputs decelerated motion. The second bearing housing 45 covers the second external tooth portion 33 and the second internal tooth portion 421 from the output side in the axial direction.

[0023] A second input bearing 47 is disposed between the second bearing housing 45 and the shaft portion 30C of the vibrator shaft 30, and the vibrator shaft 30 is rotatably supported by the second bearing housing 45. Although a ball bearing is shown as an example of the second input bearing 47, other radial bearings may also be used. An oil seal 543 is provided between the second bearing housing 45 and the shaft portion 30C of the vibrator shaft 30, on the output side of the second input bearing 47, to prevent the lubricant from leaking outward in the axial direction (toward the output side). The second bearing housing 45 may be formed integrally with the second main body member 42.

[0024] Furthermore, an O-ring 551 for sealing is interposed between the first main body member 41 and the casing 43. Similarly, a sealing O-ring 552 is interposed between the first main body member 41 and the first bearing housing 44, and a sealing O-ring 553 is interposed between the second main body member 42 and the second bearing housing 45. Therefore, the internal space of the flexible meshing gear device 1 (the meshing portion between the first external tooth portion 32 and the first internal tooth portion 411, the meshing portion between the second external tooth portion 33 and the second internal tooth portion 421, the space where the main bearing 48, the first input bearing 46, the second input bearing 47, the vibrator bearing 31, etc. are present) is a lubricant-filled space in which a lubricant is filled, and is sealed by oil seals 541-543 and O-rings 551-553.

[0025] [Regarding the fit between the first and second bearing housings] Here, the fitting of the first bearing housing 44 and the second bearing housing 45 in the flexible mesh gear device 1 will be described in detail.

[0026] FIG. 2 is an enlarged cross-sectional view of the first bearing housing 44 and its surroundings. As shown in the figure, the first bearing housing 44 is an approximately cylindrical body whose entire body is centered on the rotation axis O1, and has a flange portion 442 extending radially outward from the outer periphery of the cylindrical body, and a protrusion portion 443 protruding in the axial direction (output side) from the flange portion 442. The protrusion 443 is inserted into the counter-output end of the cylindrical first main body member 41 and fitted with a spigot. In this fitted state, the counter-output end face of the first main body member 41 abuts against the output end face of the flange portion 442.

[0027] The flange portion 442 has a plurality of insertion holes 442a formed axially at uniform intervals around the circumference, and the first connecting member 441 inserted into these insertion holes 442a is screwed into a screw hole formed on the end face of the first main body member 41 on the non-output side, connecting the first bearing housing 44 to the first main body member 41 through the flange portion 442. In the following description, the mating surface formed by the anti-output side end face of the first main body member 41 and the output side end face of the flange portion 442 is referred to as the connecting portion J of the first connecting member 441. A spacer or the like may be interposed between the mating surface formed by the anti-output side end face of the first main body member 41 and the output side end face of the flange portion 442.

[0028] An O-ring groove 444 is formed around the entire outer periphery of the protruding portion 443 of the first bearing housing 44, and the above-mentioned O-ring 552 is housed therein. A fitting portion P is formed by spigot fitting between the outer periphery of the protruding portion 443 and the inner periphery of the first main body member 41, and within the fitting portion P, a portion that is farther from the connecting portion J than the O-ring groove 444 is defined as a first fitting portion P1, and a portion that is closer to the connecting portion J than the O-ring groove 444 is defined as a second fitting portion P2. In other words, the first fitting portion P1 is provided on the tip side of the protruding portion 443, and the second fitting portion P2 is provided on the base side of the protruding portion 443 (the side closer to the flange portion 442 and the connecting portion J). The "fitting portion" here refers to the range in which the outer periphery of the protruding portion 443 and the inner periphery of the first main body member 41 are approximately parallel to each other in the axial direction and face each other in the radial direction. Therefore, the range of the inclined surface that is clearly not parallel to the axial direction, such as the chamfered portion of the output side end of the protruding portion 443, is not included in the range of the fitting portion P.

[0029] Regarding the fit between the outer periphery of the protrusion 443 and the inner periphery of the first main body member 41, the interference of the second fitting portion P2 is set to be larger than the interference of the first fitting portion P1. Note that the term "interference" as used herein means that a positive value indicates a state in which tightness has occurred, and a negative value indicates a state in which a gap has occurred. Therefore, when it is said that "the interference of the second fitting portion P2 is greater than the interference of the first fitting portion P1," it does not necessarily mean that both the second fitting portion P2 and the first fitting portion P1 are "tight fit," but also includes cases in which the second fitting portion P2 is "tight fit" and the first fitting portion P1 is "intermediate fit" or "loose fit," or cases in which the second fitting portion P2 is "intermediate fit" and the first fitting portion P1 is "loose fit," and further, depending on the numerical value of the interference, cases in which both the second fitting portion P2 and the first fitting portion P1 are "intermediate fit," or cases in which both the second fitting portion P2 and the first fitting portion P1 are "loose fit." Here, an example is shown in which the second fitting portion P2 is an "interference fit" and the first fitting portion P1 is an "intermediate fit" or "loose fit".

[0030] Furthermore, the inner diameter of the inner periphery of the first bearing housing 44 is larger on the output side than on the non-output side via a step. The inner periphery on the output side of this first bearing housing 44 forms a bearing fitting portion 445, and the outer ring of the above-mentioned first input bearing 46 is fitted into the inside of this bearing fitting portion 445 by a spigot. The fit between this bearing fitting portion 445 and the outer ring of the first input bearing 46 is exemplified as an "intermediate fit" or an "interference fit". Furthermore, the fit between the inner ring of the first input bearing 46 and the outer periphery of the shaft portion 30B of the vibrator shaft 30 is a "loose fit" as an example.

[0031] 2, the range A0 of the fitting portion P in the axial direction and the range A3 of the bearing fitting portion 445 overlap when viewed from the radial direction. As shown in the figure, the range A0 of the fitting portion P may overlap so that the entire range A0 is included in the range A3 of the bearing fitting portion 445, or a portion of the range A0 of the fitting portion P and a portion of the range A3 of the bearing fitting portion 445 may overlap when viewed from the radial direction. In that case, however, of the range A1 of the first fitting portion P1 and the range A2 of the second fitting portion P2 in the axial direction, it is preferable that at least the range A2 of the second fitting portion P2 overlaps with the range A3 of the bearing fitting portion 445 when viewed from the radial direction. As shown in FIG. 2, it is preferable that the range A2 of the second fitting portion P2 in the axial direction be set wider than the range A1 of the first fitting portion P1.

[0032] On the other hand, the second bearing housing 45 is an approximately cylindrical body whose entire body is centered on the rotation axis O1, and has a flange portion 451 extending radially outward from the outer periphery of the output side end, and a protrusion portion 452 protruding in the axial direction (opposite the output side) from the flange portion 451. The second bearing housing 45 has the protrusion 452 inserted into the inside of the output-side end of the second main body member 42 and fitted with a spigot. In this fitted state, the output-side end face of the second main body member 42 abuts against the non-output-side end face of the flange portion 451 of the second bearing housing 45.

[0033] As described above, the second bearing housing 45 is connected to the mating member 56 and the second main body member 42 via the flange portion 451 by the second connecting member (A) 561, and is connected to the second main body member 42 by the second connecting member (B) 533. The second connecting member (B) 533 is a bolt having the same outer diameter as the first connecting member 441 described above, and the second connecting member (A) 561 is a bolt having an outer diameter larger than that of the first connecting member 441. Furthermore, the total number of second connecting members (A) 561 and second connecting members (B) 533 for connecting the second bearing housing 45 to the second main body member 42, etc. is greater than the number of first connecting members 441 for connecting the first bearing housing 44 to the first main body member 41. With these configurations, the overall connecting force between the second bearing housing 45 and the second main body member 42 by the second connecting member (A) 561 and the second connecting member (B) 533 is set to be greater than the overall connecting force between the first bearing housing 44 and the first main body member 41 by the first connecting member 441.

[0034] An O-ring groove is formed around the entire outer periphery of the protruding portion 452 of the second bearing housing 45, and the above-mentioned O-ring 553 is stored in the groove. Between the outer periphery of the protruding portion 452 and the inner periphery of the second main body member 42, a fitting portion Q is formed by spigot fitting. The fit between the outer periphery of the protrusion 452 and the inner periphery of the second main body member 42 is constant over the entire axial length of the fitting portion Q, except for the portion that becomes the O-ring groove. The fit of the fitting portion Q is exemplified as an "intermediate fit" or a "loose fit."

[0035] The inner diameter of the second bearing housing 45 is larger on the non-output side than on the output side via a step. The inner periphery on the non-output side of the second bearing housing 45 forms a bearing fitting portion, and the outer ring of the second input bearing 47 described above is fitted into the inside of this bearing fitting portion by a spigot. The fit between this bearing fitting portion and the outer ring of the second input bearing 47 is an "intermediate fit" or "interference fit." The fit between the inner ring of the second input bearing 47 and the outer periphery of the shaft portion 30C of the vibrator shaft 30 is a "loose fit."

[0036] [Deceleration operation] The above-mentioned flexible mesh gear device 1 is a cylindrical flexible mesh gear device having a first internal tooth portion 411 and a second internal tooth portion 421 as an internal gear, and the reduced rotation is output to the mating member 56 via the second internal tooth portion 421. That is, when rotational motion is input from a motor (not shown) or the like and the vibrator shaft 30 rotates, the motion of the vibrator 30A is transmitted to the first external toothed portion 32 and the second external toothed portion 33. At this time, the first external toothed portion 32 and the second external toothed portion 33 are restricted to a shape that follows the outer circumferential surface of the vibrator 30A and are bent into an elliptical shape having a major axis portion and a minor axis portion when viewed from the axial direction. Furthermore, the first external toothed portion 32 is engaged with the first internal toothed portion 411 of the fixed first main body member 41 at the major axis portion. Therefore, the first external toothed portion 32 and the second external toothed portion 33 do not rotate at the same rotational speed as the vibrator 30A, and the vibrator 30A rotates relatively inside the first external toothed portion 32 and the second external toothed portion 33. As a result of this relative rotation, the first external toothed portion 32 and the second external toothed portion 33 are flexibly deformed such that the major axis position (a position on an extension of the major axis of the vibrator 30A) and the minor axis position (a position on an extension of the minor axis of the vibrator 30A) move in the circumferential direction. The period of this deformation is proportional to the rotation period of the vibrator shaft 30.

[0037] When the first external toothed portion 32 and the second external toothed portion 33 flexibly deform, their major axis positions move, causing the meshing position between the first external toothed portion 32 and the first internal toothed portion 411 to change in the rotational direction. If the number of teeth of the first external toothed portion 32 is 100 and the number of teeth of the first internal toothed portion 411 is 102, the meshing teeth of the first external toothed portion 32 and the first internal toothed portion 411 will shift each time the meshing position makes one rotation, causing the first external toothed portion 32 to rotate (spin on its axis). With the above number of teeth, the rotational motion of the vibrator shaft 30 is decelerated at a reduction ratio of 100:2 and transmitted to the first external toothed portion 32.

[0038] Meanwhile, the second external toothed portion 33, which shares the base 34 with the first external toothed portion 32, meshes with the second internal toothed portion 421, and therefore the meshing position between the second external toothed portion 33 and the second internal toothed portion 421 also changes in the rotational direction as the vibrator shaft 30 rotates. Meanwhile, because the number of teeth of the second internal toothed portion 421 matches the number of teeth of the second external toothed portion 33, the second external toothed portion 33 and the second internal toothed portion 421 do not rotate relative to each other, and the rotational motion of the second external toothed portion 33 is transmitted to the second internal toothed portion 421 at a reduction ratio of 1:1. As a result, the rotational motion of the vibrator shaft 30 is decelerated at a reduction ratio of 100:2 and transmitted to the second main body member 42 and the second bearing housing 45. This decelerated rotational motion is then output to an external member.

[0039] [Technical Effects of the Embodiments of the Invention] In the flexible mesh gear device 1, the interference of the second fitting portion P2 is set to be larger than that of the first fitting portion P1 at the fitting portion P between the first bearing housing 44 and the first main body member 41. The first fitting portion P1 is provided on the tip side of the protruding portion 443 of the first bearing housing 44, and the second fitting portion P2 is provided on the base side of the protruding portion 443. Therefore, when inserting the protrusion 443 of the first bearing housing 44 into the first main body member 41, the interference of the first fitting portion P1 at the tip side is smaller than that of the second fitting portion P2, making insertion easy and enabling smooth assembly of the device.

[0040] Furthermore, since the second fitting portion P2 has a larger interference fit than the first fitting portion P1, even if a load acts on the first input bearing 46 due to misalignment caused by an external load on the device or an external load when transmitting power to the vibrator shaft 30, slippage at the connecting portion J, which is the mating surface between the first main body member 41 and the first bearing housing 44, and at the seat surface of the first connecting member 441 is reduced, thereby suppressing loosening of the first connecting member 441 and making it possible to maintain the proper connection state between the first main body member 41 and the first bearing housing 44. In particular, by providing a tight fit for the second mating portion P2 and a clearance fit or intermediate fit for the first mating portion P1, the above assembly can be performed more effectively, and the proper connection state between the first main body member 41 and the first bearing housing 44 can be maintained more effectively.

[0041] Furthermore, in the fitting portion P, an O-ring groove 444 is provided on the outer periphery of the protruding portion 443 between the first fitting portion P1 and the second fitting portion P2, and an O-ring 552 is disposed therein as a sealing member. Meanwhile, because the interference of the first fitting portion P1 is set smaller than that of the second fitting portion P2, when inserting the protruding portion 443 of the first bearing housing 44 into the first body member 41, the insertion operation can proceed smoothly at least up to the range of the first fitting portion P1 and the O-ring groove 444 on the tip side. This minimizes damage to the sliding surface of the O-ring 552 during insertion, and by protecting the O-ring 552, it is possible to effectively reduce leakage of internal lubricant in the device. Furthermore, by suppressing leakage of internal lubricant, the flexible mesh gear device 1 can operate stably for a long period of time.

[0042] Furthermore, the first bearing housing 44 is set so that the fitting portion P and the bearing fitting portion 445 overlap when viewed from the radial direction. In this case, the second fitting portion P2 included in the fitting portion P can more effectively reduce slippage along the radial direction of the connecting portion J between the first main body member 41 and the first bearing housing 44 and the seat surface of the first connecting member 441 due to the load transmitted from the first input bearing 46, making it possible to more effectively maintain the connected state between the first main body member 41 and the first bearing housing 44.

[0043] Furthermore, on the output side, the flexible mesh gear device 1 is configured so that the overall connecting force between the second main body member 42 and the second bearing housing 45 by the second connecting member (A) 561 and the second connecting member (B) 533 is greater than the overall connecting force between the first main body member 41 and the first bearing housing 44 by the first connecting member 441. Therefore, unlike the case of the first main body member 41 and the first bearing housing 44, slippage is less likely to occur between the mating surfaces of the second main body member 42 and the second bearing housing 45 and the seating surfaces of the second connecting member (A) 561 and the second connecting member (B) 533, and loosening is less likely to occur. Therefore, at the fitting portion Q between the second main body member 42 and the second bearing housing 45, it is not necessary to change the interference between the downstream side and the upstream side in the fitting direction of the second bearing housing 45, and it can be kept constant. This makes it easier to process the second main body member 42 or the second bearing housing 45, making it possible to facilitate the manufacture of the flexible mesh gear device 1 and reduce processing costs.

[0044] [others] The details shown in the above embodiment can be modified as appropriate without departing from the spirit of the invention. For example, in the flexible mesh gear device 1 shown in the above embodiment, the protrusion 443 of the first bearing housing 44 is inserted into the inside of the first main body member 41 to achieve spigot fitting, but the present invention is not limited to this. For example, the first bearing housing 44 may have a cylindrical portion with a larger inner diameter on the output side, into which the end of the first main body member 41 on the non-output side can be inserted, and the first main body member 41 may be spigot fitted. In this case, the inner periphery of the first bearing housing 44 and the outer periphery of the first body member 41 form a fitting portion, and the interference is greater on the base side than on the tip side in the insertion direction at the end of the first body member 41 on the anti-output side.

[0045] Furthermore, in the above embodiment, an example was shown in which the gear device was a flexible mesh gear device, but the gear device according to the present invention may be any type of gear device as long as it has a gear mechanism including an internal gear and an external gear. For example, the gear device according to the present invention may be a center crank type eccentric oscillating gear device, a so-called distribution type eccentric oscillating gear device in which two or more shafts having eccentric bodies are arranged offset from the axis of the gear device, or a simple planetary gear device. Furthermore, in the above embodiment, an example was shown in which the gear device was a so-called cylindrical type flexible mesh gear device, but the reduction gear according to the present invention may also be a so-called cup type or top hat type flexible mesh gear device. In the above embodiment, the connecting member is a bolt, but the type of the connecting member is not particularly limited, and it may be, for example, a connecting pin. In the above embodiment, the number of second connecting members is greater than the number of first connecting members, so the connecting force of the second connecting members is greater than the connecting force of the first connecting members. However, this is not limited to this, and the connecting force may be increased by, for example, increasing the bolt diameter, increasing the pitch circle diameter of the bolt, or using different types of connecting members. [Explanation of symbols]

[0046] 1. Flexible mesh gear system (gear system) 30 Vibrator shaft (input shaft) 30A vibrator 31 Vibrator bearing 35 External gear 56 Counterpart 41 first body member 411 First internal tooth part (internal gear) 42 second body member 421 Second internal tooth part (internal gear) 44 First bearing housing 441 First connecting member 442 Flange 443 Protrusion 444 O-ring groove 445 Bearing fitting part 45 Second bearing housing 451 Flange 452 Protrusion 551~553 O-ring (sealing material) J connection part O1 Rotational Axis P,Q fitting part P1 First fitting part P2 Second mating part

Claims

1. An input shaft; a first input bearing supporting the input shaft; a first bearing housing that supports the first input bearing; a first body member to which the first bearing housing is connected; an external gear; an internal gear; A gear train comprising: the first bearing housing is disposed on one axially lateral side of the external gear, the first bearing housing and the first body member are fitted together at a fitting portion and connected together by a first connecting member, the fitting portion has a first fitting portion that is farther from the connection portion formed by the first connection member and a second fitting portion that is closer to the connection portion than the first fitting portion, The interference of the second fitting portion is greater than the interference of the first fitting portion, Furthermore, the interference of the second fitting portion is larger than the interference of the fitting portion between a second body member and a second bearing housing, which has a second input bearing that supports the input shaft at a position different from the first input bearing and is located on the other axial side of the first bearing housing with the external gear sandwiched therebetween. Gearing.

2. A seal member is disposed between the first fitting portion and the second fitting portion.

2. The gear device of claim 1.

3. the first bearing housing has a flange portion connected by the first connecting member and a protrusion protruding in the axial direction from the flange portion, The first fitting portion is provided on the tip side of the protrusion, and the second fitting portion is provided on the base side of the protrusion.

3. A gear device according to claim 1 or 2.

4. The second fitting portion is an interference fit, and the first fitting portion is a clearance fit or an intermediate fit. A gearing according to any one of claims 1 to 3.

5. The first bearing housing has a bearing fitting portion that fits with the first input bearing, and the fitting portion and the bearing fitting portion overlap when viewed in a radial direction. A gearing according to any one of claims 1 to 4.

6. The input shaft is a vibrator shaft having a vibrator that causes the external gear to flexibly deform. A gearing according to any one of claims 1 to 5.

7. The internal gear is a cylindrical flexible mesh gear device having a first internal gear and a second internal gear, The reduced rotation is output to a mating member via the second internal gear, and the first body member is integrated with the first internal gear.

7. The gearing of claim 6.

8. An input shaft, a first input bearing supporting the input shaft; a first bearing housing that supports the first input bearing; a first body member to which the first bearing housing is connected; an external gear; an internal gear; A gear train comprising: the first bearing housing and the first body member are fitted together at a fitting portion and connected together by a first connecting member, the fitting portion has a first fitting portion that is farther from the connection portion formed by the first connection member and a second fitting portion that is closer to the connection portion than the first fitting portion, The interference of the second fitting portion is greater than the interference of the first fitting portion, the input shaft is a vibrator shaft having a vibrator that flexibly deforms the external gear, The internal gear is a cylindrical flexible mesh gear device having a first internal gear and a second internal gear, The reduced rotation is output to a mating member via the second internal gear, and the first body member is integrated with the first internal gear, a second bearing housing connected by a second connecting member to a second body member integrated with the second internal gear; a second input bearing disposed in the second bearing housing and supporting the input shaft; The connecting force of the second connecting member is greater than the connecting force of the first connecting member, The fitting portion between the second bearing housing and the second body member has a constant interference. Gearing.

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