Lubricant leakage prevention mechanism and gear mechanism

Abstract

A lubricant leakage suppression mechanism (1) according to the embodiment is provided with: an output block body (14) that is provided on at least one surface of both surfaces of a ring gear (4) in the thickness direction and that has an outer peripheral surface (14d) over the whole periphery so as to be adjacent in the thickness direction to external teeth (4a) of the ring gear (4); a cover (15) that is provided over the whole periphery to face the external teeth (4a) in the radial direction and covers the external teeth (4a); and a felt sheet (16) that seals a gap between the output block body (14) and the cover (15).

Description

[Technical field]

[0001] The present invention relates to a lubricant leakage suppression mechanism and a gear mechanism. This application claims priority based on Japanese Patent Application No. 2021-210764, filed in Japan on December 24, 2021, and Japanese Patent Application No. 2022-106001, filed in Japan on June 30, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] Large bearings are used in construction machinery, wind turbines, and the like to support a rotating body so that it can rotate freely. For example, a rolling bearing having an inner ring, an outer ring, and rolling elements provided between the inner ring and the outer ring is used as this bearing. Bearings used in construction machinery, wind turbines, and the like are subjected to large loads. For this reason, various techniques have been disclosed for preventing leakage of the lubricant that lubricates the sliding parts of the bearing.

[0003] For example, a technology has been disclosed in which seal members are attached to both ends of the rolling element holding surfaces of the outer and inner rings that face each other with the rolling elements interposed therebetween, and a space is provided between the seal members. In this technology, pressurized fluid is supplied to the space to press the lip of the seal member against the mating wall surface, thereby improving the sealing performance of the seal member. This makes it possible to prevent leakage of lubricant from the sliding parts of the bearing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent No. 4563510 Summary of the Invention [Problem to be solved by the invention]

[0005] In some cases, a gear is integrally provided on the bearing itself, and the outer or inner ring of the bearing itself is used as a drive wheel by meshing this gear with another gear such as a pinion gear to which power is input. In such cases, a lubricant is often used to mesh the gear provided on the bearing with the other gear. It is desirable to prevent leakage of this lubricant.

[0006] However, while the above-mentioned conventional technology can prevent leakage of lubricant from the sliding parts of the bearings, it is difficult to prevent leakage of the lubricant used for meshing the gears in the immediate vicinity of the gears. If an attempt is made to cover the entire gear with a cover and provide a sealing mechanism therein in order to prevent leakage of the lubricant at a position away from the gears, there is a problem that the entire device becomes large in size.

[0007] The present invention provides a lubricant leakage prevention mechanism and a gear mechanism that can prevent an increase in size of the device by suppressing leakage of lubricant used in the meshing of the gears in the immediate vicinity of the gears. [Means for solving the problem]

[0008] A lubricant leakage prevention mechanism according to one embodiment of the present invention comprises a gear, a block body provided on at least one of the thickness-wise faces of the gear and having a peripheral surface around the entire circumference so as to be adjacent to the tooth portion of the gear in the thickness direction, a cover provided around the entire circumference so as to face the tooth portion in the radial direction of the gear and covering the tooth portion, and a sealing member providing a seal between the block body and the cover.

[0009] In this way, the gap between the block body arranged next to the teeth of the gears and the cover that covers the teeth is sealed with a seal member, which makes it possible to prevent leakage of the lubricant used for meshing the gears in the immediate vicinity of the gears and to prevent the device from becoming large in size.

[0010] In the above configuration, the sealing member may be made of a compressible and deformable porous material.

[0011] In the above configuration, the cover may have a cover protruding portion protruding from the cover toward the tooth portion, and the seal member may be provided between the cover protruding portion and the block body.

[0012] In the above configuration, the block body may have a block body protruding portion that protrudes from the peripheral surface toward the cover, and the seal member may be provided between the block body protruding portion and the cover.

[0013] In the above configuration, the cover may have a cover protrusion portion protruding from the cover toward the tooth portion, and the block body may have a block body protrusion portion protruding from the circumferential surface toward the cover, and the seal member may be sandwiched in the thickness direction between the cover protrusion portion and the block body protrusion portion.

[0014] In the above configuration, the cover has a cover protrusion portion that protrudes from the cover toward the tooth portion, and an auxiliary cover that is provided at a position farther away from the gear in the thickness direction than the cover protrusion portion, and the auxiliary cover may clamp the sealing member in the thickness direction together with the cover protrusion portion.

[0015] In the above configuration, the seal member may be interposed in a gap between the cover protruding portion and the peripheral surface of the block body.

[0016] In the above configuration, the seal member may be in surface contact with the block body and the cover.

[0017] The above-mentioned configuration may include a pressing portion that locally presses the seal member.

[0018] In the above configuration, the pressing portion can be formed continuously or discontinuously in the circumferential direction of the gear.

[0019] In the above configuration, the pressing portion is formed on at least one of the block body and the cover, and can press the seal member in the radial direction of the gear or in the axial direction of the gear.

[0020] In the above configuration, the pressing portion can be formed to be convex or concave in a direction in which the seal member is pressed.

[0021] In the above configuration, the pressing portion may be formed so as to be convex in a direction in which the sealing member is pressed, and the top portion of the pressing portion may be rounded.

[0022] In the above configuration, the pressing portion can be formed so that a distance between opposing surfaces of the block body and the cover is narrowed.

[0023] A lubricant leakage suppression mechanism according to another aspect of the present invention includes a gear having teeth on its outer peripheral surface, a block body provided on at least one of both surfaces in the thickness direction of the gear and having an outer peripheral surface around the entire circumference so as to be adjacent to the teeth in the thickness direction, a cover covering the teeth from the radial outside, and a seal member providing a seal between the block body and the cover, wherein the cover has a cover protrusion protruding radially inward from the cover, and the block body has a block body protrusion protruding radially outward from the outer peripheral surface, and the seal member is sandwiched between the cover protrusion and the block body protrusion in the thickness direction.

[0024] In this way, the gap between the block body arranged next to the teeth of the gear and the cover that covers the teeth is sealed by the seal member, which makes it possible to prevent leakage of the lubricant used for meshing the gears in the immediate vicinity of the gears. The gap between the cover and the block body can be narrowed by providing the cover protrusion and the block body protrusion. Moreover, by sandwiching the seal member in the thickness direction of the gear, the lubricant leakage suppression mechanism can be prevented from becoming large in the radial direction, and the seal member can be made thinner. This allows the lubricant leakage suppression mechanism to be made smaller.

[0025] A lubricant leakage suppression mechanism according to another aspect of the present invention comprises: a block body that is provided on at least one of both faces in a thickness direction of a gear having teeth on its outer peripheral surface and has an outer peripheral surface over the entire circumference so as to be adjacent to the teeth in the thickness direction; a cover that covers the teeth from the radially outside; and a seal member that seals between the block body and the cover, wherein the cover has a cover overhanging portion that overhangs radially inward from the cover, and an auxiliary cover that is provided at a position spaced apart from the gear in the thickness direction than the cover overhanging portion, and the block body has a block body overhanging portion that overhangs radially outward from the outer peripheral surface, the cover overhanging portion and the block body overhanging portion sandwich the seal member in the thickness direction, and the cover overhanging portion and the auxiliary cover sandwich the seal member in the thickness direction between the cover and the block body overhanging portion, and the seal member is interposed in a gap between the cover overhanging portion and the outer peripheral surface of the block body.

[0026] In this way, the seal member is sandwiched in the thickness direction by the cover overhang and the block body overhang, and the seal member is sandwiched in the thickness direction by the cover overhang and the auxiliary cover between the cover and the block body overhang. This makes it possible to prevent the seal member itself from rotating relative to the cover and the block body while suppressing leakage of lubricant used for meshing the gears in the immediate vicinity of the gears. The auxiliary cover prevents dust from entering the cover from the outside.

[0027] A gear mechanism according to another aspect of the present invention comprises: an annular gear that is integrated with an outer ring of a bearing and has teeth on its outer periphery; a block body that is provided on one face in the thickness direction of the annular gear and has an outer periphery over the entire circumference so as to be adjacent to the teeth in the thickness direction; a cover that covers the teeth from the radially outside; and a seal member that provides a seal between the block body and the cover, wherein the cover has a cover protrusion that protrudes radially inward from the cover, and the block body has a block body protrusion that protrudes radially outward from the outer periphery, and the seal member is sandwiched between the cover protrusion and the block body protrusion in the thickness direction.

[0028] In this way, the gap between the block body arranged next to the teeth of the ring gear and the cover that covers the teeth is sealed with a seal member, which makes it possible to prevent leakage of lubricant used for gear meshing in the immediate vicinity of the ring gear. The gap between the cover and the block body can be narrowed by providing the cover protrusion and the block body protrusion. Moreover, by sandwiching the seal member in the thickness direction of the gear, the radial size of the lubricant leakage suppression mechanism can be prevented from increasing, and the seal member can be made thinner. This allows the gear mechanism to be made more compact.

[0029] A gear mechanism according to another aspect of the present invention includes an annular gear that is integrated with an outer ring of a bearing and has teeth on its outer periphery; a block body that is provided on one surface in a thickness direction of the annular gear and has an outer periphery over the entire circumference so as to be adjacent to the teeth in the thickness direction; a cover that covers the teeth from the outside in the radial direction; and a seal member that seals between the block body and the cover, wherein the cover has a cover overhanging portion that overhangs radially inward from the cover, and an auxiliary cover that is provided at a position spaced apart from the annular gear in the thickness direction than the cover overhanging portion, and the block body has a block body overhanging portion that overhangs radially outward from the outer periphery, and the seal member is sandwiched in the thickness direction by the cover overhanging portion and the block body overhanging portion, and the seal member is sandwiched in the thickness direction between the cover and the block body overhanging portion by the cover overhanging portion and the auxiliary cover, and the seal member is interposed in a gap between the cover overhanging portion and the outer periphery of the block body.

[0030] With this configuration, it is possible to prevent the seal member itself from rotating relative to the cover and the block body while suppressing leakage of the lubricant used for gear meshing in the immediate vicinity of the ring gear. The auxiliary cover prevents dust from entering the cover from the outside. Effect of the Invention

[0031] The above-described lubricant leakage prevention mechanism and gear mechanism can prevent the device from becoming large by preventing leakage of the lubricant used for meshing the gears in the immediate vicinity of the gears. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a perspective view of a positioner according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] 1 is an enlarged sectional perspective view of a lubricant leakage prevention mechanism according to a first embodiment of the present invention. FIG. [Figure 4] FIG. 11 is an enlarged sectional perspective view of a lubricant leakage prevention mechanism according to a second embodiment of the present invention. [Diagram 5] FIG. 11 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a third embodiment of the present invention. [Figure 6] FIG. 11 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a fourth embodiment of the present invention. [Figure 7] FIG. 13 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a fifth embodiment of the present invention. [Figure 8] FIG. 13 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a sixth embodiment of the present invention. [Figure 9] FIG. 13 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a seventh embodiment of the present invention. [Figure 10] FIG. 13 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to an eighth embodiment of the present invention. [Figure 11] FIG. 13 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a ninth embodiment of the present invention. [Figure 12] FIG. 23 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a tenth embodiment of the present invention. [Figure 13] 4 is a perspective view illustrating a compression direction of a seal member in the lubricant leakage prevention mechanism according to the embodiment of the present invention. FIG. [Figure 14] FIG. 23 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to an eleventh embodiment of the present invention. [Figure 15]FIG. 23 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a twelfth embodiment of the present invention. [Figure 16] 4 is a perspective view illustrating a compression direction of a seal member in the lubricant leakage prevention mechanism according to the embodiment of the present invention. FIG. [Figure 17] FIG. 23 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a thirteenth embodiment of the present invention. [Figure 18] FIG. 23 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a fourteenth embodiment of the present invention. [Figure 19] FIG. 23 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a fifteenth embodiment of the present invention. [Figure 20] FIG. 23 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a sixteenth embodiment of the present invention. [Figure 21] FIG. 23 is an enlarged cross-sectional view of a lubricant leakage prevention mechanism according to a seventeenth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Next, an embodiment of the present invention will be described with reference to the drawings.

[0034] [First embodiment] <Positioner> Fig. 1 is a perspective view of a positioner 100, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 1. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. The positioner 100 is used in, for example, construction machinery or industrial machinery (not shown). The positioner 100 is used to adjust the orientation of a rotating body (not shown) attached to the positioner 100.

[0035] 1 and 2, positioner 100 includes a plate-shaped base portion 2, a bearing 3 attached to base portion 2, an annular gear (ring gear, an example of a gear in the claims) 4 provided integrally with the outer circumferential surface of bearing 3, a lubricant leakage suppression mechanism (hereinafter simply referred to as leakage suppression mechanism) 1 provided in the vicinity of annular gear 4, and a power unit 5 that transmits power to annular gear 4. In the following description, unless otherwise specified, the direction of rotation axis L of annular gear 4 will be simply referred to as axial direction, the radial direction of annular gear 4 will be simply referred to as radial direction, and the circumferential direction of annular gear 4 will be simply referred to as circumferential direction.

[0036] The base portion 2 has a bearing mounting portion 6 which is annular when viewed in the thickness direction of the base portion 2, and a power mounting portion 7 which is integrally formed on one side of the bearing mounting portion 6. The bearing 3 is attached to the bearing mounting portion 6. The power unit 5 is attached to the power mounting portion 7.

[0037] <Bearings> The bearing 3 is a rolling bearing including an inner ring 8, an outer ring 9, and rolling elements 10 provided between the inner ring 8 and the outer ring 9. The inner diameter of the inner ring 8 is substantially the same as the inner diameter of the bearing mounting portion 6. The inner ring 8 is formed with a plurality of bolt holes (not shown) penetrating in the axial direction. The bearing mounting portion 6 is formed with a female thread (not shown) at a position corresponding to the bolt hole of the inner ring 8. The inner ring 8 is fixed to the bearing mounting portion 6 by inserting a bolt 11 into the bolt hole from above the inner ring 8 and tightening the bolt 11 into the female thread of the bearing mounting portion 6. As the rolling elements, rolling elements of various shapes such as spherical, cylindrical rollers, and conical rollers can be used.

[0038] The outer ring 9 is slightly offset with respect to the inner ring 8 in a direction away from one surface 6a of the bearing attachment portion 6. That is, a slight gap S is formed between the outer ring 9 and the bearing attachment portion 6. Due to the offset between the outer ring 9 and the inner ring 8, one surface 9a of the outer ring 9 opposite the bearing attachment portion 6 protrudes from the inner ring 8 toward the opposite side to the bearing attachment portion 6. On the side of the one surface 9a of the outer ring 9 protruding from the inner ring 8, an annular first seal portion 12 is provided on an inner circumferential surface 9b. One surface 8a of the inner ring 8 placed on one surface 6a of the bearing attachment portion 6 protrudes from the outer ring 9 toward the bearing attachment portion 6. On the side of the one surface 8a of the inner ring 8 protruding from the outer ring 9, an annular second seal portion 13 is provided on an outer peripheral surface 8b.

[0039] These seal portions 12, 13 provide a seal between the inner ring 8 and the outer ring 9. This prevents leakage of lubricant (not shown) around the rolling elements 10 of the bearing 3 (the bearing sliding portion). An annular gear 4 is provided integrally with the outer peripheral surface of the outer ring 9. The annular gear 4 has external teeth 4a. A leakage suppression mechanism 1 is provided to surround the periphery of the annular gear 4.

[0040] <Leak prevention mechanism> FIG. 3 is an enlarged perspective sectional view of the leakage prevention mechanism 1. As shown in FIG. As shown in Figures 2 and 3, the leakage suppression mechanism 1 comprises an annular output block body (an example of a block body in the claims) 14 provided on one surface 9a of the outer ring 9 (annular gear 4), a cover 15 that covers the annular gear 4 and the power unit, and a felt sheet (an example of a sealing member, porous material in the claims) 16 that seals between the output block body 14 and the cover 15.

[0041] The output block body 14 has a radial cross section formed into a rectangular shape that is long in the radial direction. A lower surface 14a of the output block body 14 on the outer ring 9 side is disposed on one surface 9a of the outer ring 9. A positioning protrusion 17 is integrally formed on the inner peripheral surface 14c of the output block body 14. A lower end 17a of the positioning protrusion 17 on the outer ring 9 side protrudes slightly from the output block body 14 toward the inner peripheral surface 9b of the outer ring 9 in the axial direction.

[0042] The inner peripheral surface 9b of the outer ring 9 abuts against the outer peripheral surface of the lower end 17a of the positioning protrusion 17, thereby positioning the output block body 14 in the radial direction with respect to the outer ring 9. The position of the upper end 17b opposite the lower end 17a of the positioning protrusion 17 is located closer to the outer ring 9 than the upper surface 14b opposite the lower surface 14a of the output block body 14. For this reason, a step is formed between the upper surface 14b of the output block body 14 and the positioning protrusion 17.

[0043] The output block body 14 is formed with a plurality of bolt holes 19 penetrating in the axial direction. The plurality of bolt holes 19 are formed at equal intervals in the circumferential direction. The outer ring 9 of the bearing 3 is formed with a female thread portion (not shown) at a position corresponding to the bolt hole 19. A bolt 20 is inserted into the bolt hole 19 from above the output block body 14. The output block body 14 is fixed to the outer ring 9 by tightening the bolt 20 into the female thread portion of the outer ring 9.

[0044] An attachment hole 24 is formed in the upper surface 14b of the output block body 14. The attachment hole 24 is formed in the upper surface 14b of the output block body 14 between bolt holes 19 adjacent to each other in the circumferential direction. The attachment hole 24 is used to attach a rotating body (mating member) (not shown) to the output block body 14. The attachment hole 24 is, for example, a female threaded portion. When attaching the rotating body (mating member) to the upper surface 14b of the output block body 14, a female threaded portion (not shown) formed in the outer ring 9 and the bolt hole 19 of the output block body 14 that communicates with the female threaded portion may be used. The rotating body (mating member) may be fastened to the upper surface 14b of the output block body 14 by a bolt other than the bolt 20. An output outer flange portion (an example of a block body protrusion portion in the claims) 18 is integrally formed on the outer peripheral surface 14d of the output block body 14. The output outer flange portion 18 protrudes radially outward toward the top surface 14b side from the axial center of the output block body 14. The outer diameter of the output outer flange portion 18 is slightly smaller than the cutting edge circle diameter of the ring gear 4.

[0045] The cover 15 includes a cylindrical cover body 31 that covers the ring gear 4 from the radial outside, and a power unit cover portion 32 that is integrally formed on one side of the cover body 31. A cover outer flange portion 21 that protrudes radially outward is formed by bending a lower end 31a of the cover body 31 on the bearing mounting portion 6 side. This cover outer flange portion 21 is fixed to the bearing mounting portion 6 by bolts 22. This fixes the cover body 31 to the bearing mounting portion 6. The position of an upper end 31b of the cover body 31 opposite the lower end 31a is a position that overlaps with the output outer flange portion 18 when viewed in the radial direction.

[0046] A cover inner flange portion 23 (an example of a cover protruding portion in the claims) that protrudes radially inward is integrally formed slightly below the upper end 31b of the cover main body 31. The cover inner flange portion 23 is joined to the cover main body 31 by, for example, welding. The cover inner flange portion 23 protrudes below the output outer flange portion 18 and to a position slightly short of the outer peripheral surface 14d of the output block body 14. This positions the cover inner flange portion 23 and the output outer flange portion 18 opposite each other in the axial direction.

[0047] A felt sheet 16 is provided so as to be sandwiched between the cover inner flange portion 23 and the output outer flange portion 18, which are opposed in the axial direction. The felt sheet 16 is made of a compressible porous material. The felt sheet 16 is slightly compressively deformed in the axial direction by the cover inner flange portion 23 and the output outer flange portion 18. This ensures sealing between the output block body 14 and the cover main body 31. An upper surface 16a of the felt sheet 16 between the cover main body 31 and the output outer flange portion 18 is exposed to the outside.

[0048] The felt sheet 16 is simply sandwiched between the cover inner flange portion 23 and the output outer flange portion 18, so the output outer flange portion 18 can slide relative to the felt sheet 16. The cover main body 31 is located on the radial outside of the felt sheet 16. The outer peripheral surface 14d of the output block body 14 is located on the radial inside of the felt sheet 16. The cover main body 31 and the outer peripheral surface 14d of the output block body 14 restrict radial movement of the felt sheet 16.

[0049] <Power unit> As shown in Figures 1 and 2, the power unit 5 includes a reduction gear section 25 attached to the other surface 7b of the power mounting section 7 of the base section 2 opposite the bearing 3, a motor section 26 attached to the side of the reduction gear section 25 opposite the power mounting section 7, and a small gear 27 attached to an output shaft (not shown) of the reduction gear section 25.

[0050] The speed reducer 25 reduces the speed of the rotation input from the motor unit 26 and outputs it. As the speed reducer 25, for example, a so-called eccentric oscillating type speed reducer having a crankshaft to which the rotation of the motor unit 26 is input and an external gear (neither shown) that oscillates and rotates in association with the rotation of the crankshaft is used. The eccentric oscillating type speed reducer obtains output rotation that is reduced from the rotation of the motor unit 26 by the oscillating rotation of the external gear.

[0051] This output rotation is transmitted to the pinion 27. The pinion 27 is disposed on the surface 7a of the power mounting portion 7, which is flush with the surface 6a of the bearing mounting portion 6. The output shaft of the reduction gear unit 25 protrudes toward the surface 7a of the power mounting portion 7 through an opening (not shown) formed in the power mounting portion 7. The pinion 27 is fixed to this protruding output shaft. As a result, the pinion 27 rotates integrally with the output shaft of the reduction gear unit 25. That is, the output rotation of the output shaft is transmitted to the pinion 27.

[0052] The pinion 27 has external teeth 27a which mesh with the external teeth 27a of the ring gear 4. A power unit cover portion 32 of the cover 15 is formed so as to cover the pinion 27 configured in this manner from the outside. The portion of the cover body 31 where the power unit cover portion 32 is formed is opened. Therefore, the meshing between the ring gear 4 and the pinion 27 is not hindered by the cover 15.

[0053] <Positioner operation and leakage prevention mechanism action> Next, the operation of the positioner 100 and the function of the leakage suppression mechanism 1 will be described. When the pinion 27 is rotated by driving the power unit 5, the ring gear 4 meshing with the pinion 27 is rotated. The ring gear 4 is integrated with the outer ring 9 of the bearing 3, so the ring gear 4 and the outer ring 9 rotate together. The output block body 14 attached to the outer ring 9 rotates together with the outer ring 9. This adjusts the orientation of the rotating body (not shown) attached to the output block body 14.

[0054] At this time, the output block body 14 is rotated relative to the cover main body 31 fixed to the base portion 2 (bearing attachment portion 6). The felt sheet 16 provided between the cover inner flange portion 23 of the cover main body 31 and the output outer flange portion 18 of the output block body 14 is simply sandwiched between the cover inner flange portion 23 and the output outer flange portion 18. For this reason, the cover inner flange portion 23 and the output outer flange portion 18 slide relative to the felt sheet 16.

[0055] During this sliding, the felt sheet 16 is kept slightly compressed and sandwiched between the cover inner flange portion 23 and the output outer flange portion 18. In other words, the cover main body 31 and the outer peripheral surface 14d of the output block body 14 restrict radial movement of the felt sheet 16. As a result, the seal between the cover inner flange portion 23 (cover 15) and the output outer flange portion 18 (output block body 14) is maintained.

[0056] A lubricant such as grease is used to ensure lubrication when the ring gear 4 and the pinion gear 27 mesh. The lubricant is applied to the entire external teeth 4a of the ring gear 4 and the entire external teeth 27a of the pinion gear 27. A cover body 31 of the cover 15 is provided around the entire circumference of the ring gear 4. The gap between this cover body 31 and the output block body 14 provided directly above the ring gear 4 (one surface 9a of the outer ring 9) is sealed by a leakage suppression mechanism 1. This prevents the lubricant used for meshing between the ring gear 4 and the pinion 27 from leaking out from around the ring gear 4.

[0057] In this manner, the above-described first embodiment includes the output block body 14 provided on one surface of the ring gear 4 (one surface 9a of the outer ring 9) and having an outer circumferential surface 14d, the cover 15 provided around the entire circumference so as to face radially opposite the external teeth 4a of the ring gear 4 and cover the ring gear 4 from the radial outside, and the felt sheet 16 that seals the gap between the output block body 14 and the cover 15. This makes it possible to prevent leakage of lubricant used for meshing between the ring gear 4 and the pinion 27 in the immediate vicinity (directly above) of the ring gear 4. Because leakage of lubricant can be prevented in the immediate vicinity of the ring gear 4, an increase in size of the positioner 100 itself can also be prevented.

[0058] The felt sheet 16, which is a compressible and porous material, is used as the sealing member that seals between the output block body 14 and the cover 15. This allows the sealing member to be manufactured at low cost. The sealing member can be easily made thin. This allows the gap between the cover inner flange portion 23 and the output outer flange portion 18 to be made as narrow as possible. This prevents the positioner 100 from becoming too large in the axial direction.

[0059] A cover inner flange portion 23 is provided on the cover main body 31, and an output outer flange portion 18 is provided on the output block body 14. A felt sheet 16 is provided between the cover inner flange portion 23 and the output outer flange portion 18 to seal the gap between the cover 15 and the output block body 14. By providing the cover inner flange portion 23 and the output outer flange portion 18 in this way, the gap between the cover 15 and the output block body 14 can be narrowed. This allows the sealing member (felt sheet 16) to be made small and simple in structure. The leakage suppression mechanism 1 can also be made smaller.

[0060] Moreover, the cover inner flange portion 23 and the output outer flange portion 18 are disposed opposite each other in the axial direction. The cover inner flange portion 23 and the output outer flange portion 18 sandwich the felt sheet 16 in the axial direction (thickness direction of the annular gear 4 (outer ring 9)). Therefore, compared to a case in which the cover inner flange portion 23 and the output outer flange portion 18 are disposed opposite each other in the radial direction, it is possible to prevent the leakage suppression mechanism 1 from becoming large in the radial direction.

[0061] For example, when attempting to clamp the felt sheet 16 in the radial direction between the cover inner flange portion 23 and the output outer flange portion 18, it is necessary to prevent the felt sheet 16 from moving (slipping out) in the axial direction. For this reason, a separate structure is required to prevent the felt sheet 16 from slipping out in the axial direction. When the felt sheet 16 is sandwiched in the axial direction between the cover inner flange portion 23 and the output outer flange portion 18, it is necessary to prevent the felt sheet 16 from moving in the radial direction (falling out). In this manner, the cover main body 31 and the outer peripheral surface 14d of the output block body 14 can restrict the radial movement of the felt sheet 16. By sandwiching the felt sheet 16 in the axial direction between the cover inner flange portion 23 and the output outer flange portion 18 in this manner, the structure of the leakage suppression mechanism 1 can be simplified.

[0062] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to Fig. 4. The same aspects as those in the first embodiment are given the same reference numerals and the description thereof will be omitted (the same applies to the following embodiments). FIG. 4 is an enlarged cross-sectional perspective view of a leakage prevention mechanism 201 according to the second embodiment of the present invention. As shown in FIG. 4, in the second embodiment, a positioner 200 includes a plate-shaped base portion 2, a bearing 3 attached to the base portion 2, an annular gear (a ring gear, an example of a gear in the claims) 4 integrally formed on the outer peripheral surface of the bearing 3, a leakage suppression mechanism (hereinafter simply referred to as the leakage suppression mechanism) 201 provided in the vicinity of the annular gear 4, and a power unit 5 that transmits power to the annular gear 4, which is similar to the first embodiment described above (the same applies to the following embodiments).

[0063] <Leak prevention mechanism> The difference between the first and second embodiments described above is that the leakage prevention mechanism 1 of the first embodiment is different from the leakage prevention mechanism 201 of the second embodiment. More specifically, the cover 215 of the leakage suppression mechanism 201 includes an auxiliary cover 41 that covers from above the upper surface 16a of the felt sheet 16 that is exposed to the outside from between the cover body 31 and the output outer flange portion 18. The auxiliary cover 41 has an L-shaped cross section along the axial and radial directions. That is, the auxiliary cover 41 includes a horizontal wall (cover inner upper flange portion) 41a that covers the felt sheet 16 from above, and a vertical wall 41b that is bent and extended from the radial outer end of the horizontal wall 41a toward the base portion 2 and along the axial direction.

[0064] The horizontal wall 41a is formed in an annular shape when viewed from the axial direction. The horizontal wall 41a extends from the outer peripheral surface of the output outer flange portion 18 to slightly protrude radially outward from the cover body 31. The vertical wall 41b covers the periphery of the upper end 31b of the cover body 31 from the radially outer side. In the second embodiment, the position in the height direction at the upper end 31b of the cover main body 31 is substantially the same as the upper surface 16a of the felt sheet 16. Therefore, the felt sheet 16 is not only sandwiched in the axial direction between the cover inner flange portion 23 and the output outer flange portion 18. The felt sheet 16 is also sandwiched in the axial direction between the cover inner flange portion 23 and the side wall 41a of the auxiliary cover 41.

[0065] The outer diameter of the outer peripheral surface 14d of the output block body 14 (the outer peripheral surface of the output block body 14 closer to the outer ring 9 of the bearing 3 than the output outer flange portion 18 of the output block body 14) gradually decreases axially toward the outer ring 9. In other words, the outer peripheral surface 14d of the output block body 14 is formed to be inclined (tapered) so as to taper toward the outer ring 9.

[0066] The inner peripheral portion 16b of the felt sheet 16 extends along the outer peripheral surface 14d of the output block body 14 to one surface 9a of the outer ring 9. That is, the inner peripheral portion 16b of the felt sheet 16 is bent toward the outer ring 9 by the outer peripheral surface 14d of the output block body 14, with the inner peripheral edge of the cover inner flange portion 23 as a fulcrum. The inner peripheral portion 16b of the felt sheet 16 is pressed by the outer peripheral surface 14d of the output block body 14 so as to be interposed in the gap between the cover inner flange portion 23 and the outer peripheral surface 14d of the output block body 14.

[0067] In this way, the second embodiment described above has the same effects as the first embodiment described above. In addition to this, the felt sheet 16 is not only sandwiched in the axial direction between the cover inner flange portion 23 and the output outer flange portion 18. The felt sheet 16 is sandwiched in the axial direction between the cover inner flange portion 23 and the side wall 41a of the auxiliary cover 41. This makes it possible to prevent the felt sheet 16 itself from rotating relative to the cover main body 31 and the output block body 14 (output outer flange portion 18). The side wall 41a completely covers the upper surface 16a of the felt sheet 16. This makes it possible to more reliably suppress leakage of the lubricant used for meshing between the pinion 27 and the ring gear 4 in the immediate vicinity (directly above) of the ring gear 4, and to prevent dust from entering the cover 15 from the outside.

[0068] The outer peripheral surface 14d of the output block body 14 is formed with an inclination (tapered shape) so that it tapers in the axial direction toward the outer ring 9. The inner peripheral portion 16b of the felt sheet 16 is pressed by the outer peripheral surface 14d of the output block body 14 so as to be interposed in the gap between the cover inner flange portion 23 and the outer peripheral surface 14d of the output block body 14. This further improves the sealing performance between the cover 15 (cover main body 31) and the output block body 14.

[0069] In the above-described second embodiment, the cover 215 is provided separately from the auxiliary cover 41. However, this is not limited to the above, and the cover 215 and the auxiliary cover 41 may be integrally formed.

[0070] [Third embodiment] Hereinafter, a third embodiment of the lubricant leakage prevention mechanism and gear mechanism according to the present invention will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 301 according to the third embodiment. The third embodiment differs from the above-described first embodiment in terms of the pressing portion (the same applies to the following fourth to eleventh embodiments).

[0071] <Leak prevention mechanism> As shown in FIG. 5, the leakage suppression mechanism 301 is formed with a protrusion 18s as a pressing portion. The pressing portion improves the sealing performance between the output block body 14 and the cover 15. The pressing portion locally presses and compresses the felt sheet 16, which is in surface contact with the output block body 14 and the cover 15, between the output block body 14 and the cover 15. Surface contact means that the contact is not a localized point or a linear contact, but that flat surfaces are in contact with each other. For example, in the third embodiment, the flat surface of the output block body 14 and the flat surface of the felt sheet 16 facing the flat surface are in contact with each other over the entire flat surface. The flat surface of the inner cover flange portion 23 of the cover 15 and the flat surface of the felt sheet 16 are in contact with each other over the entire flat surface.

[0072] The felt sheet 16 provides a seal between the output block body 14 and the cover 15 so that the lubricant used for the ring gear 4 does not leak to the outside through the felt sheet 16. At this time, the felt sheet 16 is sandwiched between the output outer flange portion 18 and the cover inner flange portion 23 and is in surface contact with each other. The felt sheet 16 is pressed from the lower surface 18a of the output outer flange portion 18 and the upper surface 23a of the cover inner flange portion 23 at the surface contact portion. The felt sheet 16 is pressed so as to be sandwiched in the axial direction. In this manner, the felt sheet 16, which is a compressible and deformable porous material, exhibits a sealing property so that the lubricant does not leak to the outside by being compressed.

[0073] In the first embodiment shown in Fig. 3, the axial distances are formed to be substantially equal over the entire circumferential and radial lengths at the opposing positions of the output outer flange portion 18 and the cover inner flange portion 23, which are in the vertical direction in the figure. In contrast, in the protrusion portion 18s of the third embodiment, the axial distance is smaller even in the portion where the output outer flange portion 18 and the cover inner flange portion 23 are in surface contact with the felt sheet 16. In other words, in the area where the protrusion portion 18s is in surface contact with the felt sheet 16, the protrusion portion 18s as a pressing portion locally compresses the felt sheet 16 more strongly than other portions. The protrusion portion 18s locally applies an axial thickness direction compressive force Pq1 shown in Fig. 13, which will be described later, to the felt sheet 16, thereby strongly compressing it.

[0074] The felt sheet 16 in contact with the protrusions 18s is pressed more strongly than the other portions. The felt sheet 16 in contact with the protrusions 18s is compressed more strongly than the other portions. This allows the felt sheet 16 to exhibit higher sealing properties that prevent the lubricant from leaking out from the inside to the outside in the radial direction, compared to a case where there is no pressing portion.

[0075] The protrusion portion 18s is formed so as to reduce the axial distance between the output outer flange portion 18 and the cover inner flange portion 23. The protrusion portion 18s is formed on the lower surface 18a of the output outer flange portion 18 facing the cover inner flange portion 23. The protrusion portion 18s protrudes from the output outer flange portion 18 toward the cover inner flange portion 23 in a direction in which the axial distance between the output outer flange portion 18 and the cover inner flange portion 23 becomes smaller.

[0076] The protrusion 18s is formed continuously around the entire radial circumference of the output outer flange portion 18. The protrusion 18s has a substantially uniform radial cross-sectional shape around the entire circumference. The protrusion 18s has a substantially uniform axial convex shape around the entire circumference. The apex of the protrusion 18s is located radially outward of the inner peripheral end 23t of the cover inner flange portion 23. The apex of the protrusion 18s is located radially outward of the outer peripheral surface 14d of the output block body 14. The apex of the protrusion 18s is located radially outward of the inner peripheral end 16t of the felt sheet 16. The apex of the protrusion 18s is radially inward of the outer peripheral surface 18r of the output outer flange portion 18. As a result, the protrusion portion 18s is formed at a position facing the upper surface 23a of the cover inner flange portion 23.

[0077] The protrusion 18s is formed as an inclined surface 18f from the top to the radially outer side of the output outer flange portion 18. The inclined surface 18f is continuous as an annular, approximately conical surface from the top of the protrusion 18s to the outer peripheral surface 18r of the output outer flange portion 18. The inclined surface 18f is not limited to this as long as it is a tapered surface. The inclined surface 18f may be continuous from the top of the protrusion portion 18s to the outer peripheral surface 18r of the output outer flange portion 18, or may be configured to be continuous from the top of the protrusion portion 18s to a position radially inward of the outer peripheral surface 18r.

[0078] The protrusion portion 18s is formed as a cylindrical surface that rises in the axial direction from the apex to the radially inner side of the output outer flange portion 18. The protrusion portion 18s may be formed as an inclined surface from the apex to the radially inner side, similar to the inclined surface 18f. The protrusions 18s are formed so that their tops are rounded. The rounded tops of the protrusions 18s are curved surfaces having a radius of curvature in a radial cross section. The tops of the protrusions 18s are also formed to have a smooth shape in the circumferential direction.

[0079] The axial distance between the top of the protrusion 18s and the upper surface 23a of the cover inner flange portion 23 is smaller than the thickness dimension of the felt sheet 16 in an unassembled state. At a radial position different from the protrusion portion 18s, the axial distance between the lower surface 18a of the output outer flange portion 18 and the upper surface 23a of the cover inner flange portion 23 may be smaller than the thickness dimension of the felt sheet 16 in an unassembled state, or may be slightly larger.

[0080] The felt sheet 16 is locally compressed in the axial direction by the ridges 18s. As a result, the lubricant used for meshing between the ring gear 4 and the pinion 27 is hindered from flowing axially from immediately adjacent (directly above) the ring gear 4 along the outer peripheral surface 14d of the output block body 14. Furthermore, the lubricant is hindered from flowing radially outward along the lower surface 18a of the output outer flange portion 18. At the same time, the lubricant is hindered from flowing axially from immediately adjacent (directly above) the ring gear 4 along the outer peripheral surface 14d of the output block body 14. The lubricant is hindered from flowing radially outward along the upper surface 23a of the cover inner flange portion 23.

[0081] The protrusions 18s can prevent the lubricant from soaking into the felt sheet 16 and leaking outward. That is, the protrusions 18s locally compress the felt sheet 16 more strongly, thereby blocking the leakage of the lubricant toward the outside. This can efficiently prevent the leakage of the lubricant in the immediate vicinity of the ring gear 4. This can also prevent the positioner 100 itself from becoming too large.

[0082] The output block body 14 is rotated relative to the cover main body 31 fixed to the base portion 2 (bearing attachment portion 6). The felt sheet 16 is simply sandwiched between the cover inner flange portion 23 and the output outer flange portion 18. Therefore, the cover inner flange portion 23 and the output outer flange portion 18 slide relative to the felt sheet 16.

[0083] Therefore, the felt sheet 16 rotates relative to the output outer flange portion 18 at a smaller rotational speed than the output outer flange portion 18. The felt sheet 16 rotates while sliding relative to the cover inner flange portion 23 fixed to the base portion 2. The felt sheet 16 locally compressed by the protrusions 18s is more likely to maintain a sandwiched state due to compression between the cover inner flange portion 23 and the output outer flange portion 18 than in the case where the protrusions 18s are not present. By providing the protrusions 18s, the gap between the cover 15 and the output block body 14 can be further narrowed. This allows the seal member (felt sheet 16) to be made small and simple in structure. The leakage suppression mechanism 301 can also be made even smaller.

[0084] Moreover, the cover inner flange portion 23, the output outer flange portion 18, and the protrusion portion 18s are disposed opposite to each other in the axial direction. The cover inner flange portion 23, the output outer flange portion 18, and the protrusion portion 18s sandwich the felt sheet 16 in the axial direction (thickness direction of the annular gear 4 (outer ring 9)). Therefore, compared to a case in which the cover inner flange portion 23 and the output outer flange portion 18 are disposed opposite to each other in the radial direction, it is possible to improve the sealing performance and further prevent the leakage suppression mechanism 301 from becoming large in the radial direction.

[0085] The rounded top of the protrusion 18s can prevent the protrusion 18s from getting caught on the felt sheet 16 between the output outer flange portion 18 and the felt sheet 16, which slide against each other in the circumferential direction. As a result, the felt sheet 16 can be prevented from being torn.

[0086] The protrusions 18s can be formed simultaneously with the outer peripheral surface 14d of the output block body 14 when manufacturing the output block body 14 and the output outer flange portion 18. In other words, when forming the output outer flange portion 18 as the step portion of the output block body 14, assuming cutting processing with a vertical lathe, for example, if the protrusions 18s are continuous around the circumference, they can be machined at the same time as the step portion. For this reason, it is preferable that the protrusions 18s have a shape that is continuous over the entire length in the circumferential direction.

[0087] In the third embodiment, the bearing 3 and the ring gear 4 are attached to the base portion 2, and then the cover 15 is attached. The felt sheet 16, which is an annular plate, is placed on the cover inner flange portion 23. Then, the output block body 14 is attached to the ring gear 4 so that the outer peripheral surface 14d is within the inner peripheral end 16t of the annular felt sheet 16.

[0088] Alternatively, the bearing 3, the ring gear 4, and the cover 15 are attached to the base portion 2. Then, the annular felt sheet 16 is attached so that the inner peripheral end 16t contacts the outer peripheral surface 14d of the output block body 14, and the felt sheet 16 is combined with the output block body 14. The output block body 14 and the felt sheet 16 are then attached to the ring gear 4.

[0089] At this time, the axial distance between the output outer flange portion 18 and the cover inner flange portion 23 is approximately the same as the thickness dimension of the felt sheet 16. The felt sheet 16, which is a compressible and deformable porous material, is sandwiched between the output outer flange portion 18 and the cover inner flange portion 23. The felt sheet 16 extends along the upper surface 23a of the cover inner flange portion 23 around its entire circumference in the radial direction.

[0090] This allows easy assembly without having to worry about the dimensional tolerances of the protruding portions 18s, thus improving the efficiency of the assembly work and shortening the assembly time while improving the sealing performance. When assembling, no fine adjustment regarding the seal is required, and sufficient sealing performance can be achieved in the leakage suppression mechanism 301 simply by sandwiching the felt sheet 16 therebetween. By forming the protrusion portion 18s integrally with the output outer flange portion 18, it is possible to reduce the number of parts and improve sealing performance.

[0091] The third embodiment has the same effects as the first embodiment described above. It is possible to improve the sealing performance of the felt sheet 16. Since the protrusions 18s can press the felt sheet 16 ahead (downstream) of the leakage flow from the outer circumferential surface 14d, which serves as a detour for the lubricant, it is possible to efficiently suppress leakage of the lubricant.

[0092] In the third embodiment, the protrusion portion 18s is formed continuously around the entire circumference in the radial direction of the outer output flange portion 18, but it may also be formed discontinuously in the circumferential direction. Alternatively, the cross-sectional shape of the protrusions 18s in the radial direction may vary in the circumferential direction. In other words, the axial projection dimension of the protrusions 18s may vary in the circumferential direction. In this case, it is preferable that the top shape of the protrusions 18s is smooth in the circumferential direction as well so that it does not get caught on the felt sheet 16 and tear the felt sheet 16.

[0093] [Fourth embodiment] A fourth embodiment of the lubricant leakage prevention mechanism and gear mechanism according to the present invention will now be described with reference to FIG. FIG. 6 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 301 according to the fourth embodiment.

[0094] <Leak prevention mechanism> As shown in Fig. 6, the leakage suppression mechanism 301 includes a ring groove 18m and an O-ring 18o as a convex shape serving as a pressing portion. The O-ring 18o as a pressing portion presses the felt sheet 16 so as to locally compress it more strongly than other portions. The O-ring 18o locally applies an axial thickness direction compressive force Pq1 shown in Fig. 13 described later, to compress the felt sheet 16 strongly. The ring groove 18m is formed in the lower surface 18a of the output outer flange portion 18. The ring groove 18m is formed around the entire circumference of the lower surface 18a of the output outer flange portion 18. The ring groove 18m is disposed radially outward of the outer peripheral surface 14d. The ring groove 18m is formed so as to be equidistant from the outer peripheral surface 14d in the radial direction.

[0095] The O-ring 18o is housed in the ring groove 18m. The O-ring 18o protrudes from the ring groove 18m toward the upper surface 23a of the cover inner flange portion 23. Therefore, the O-ring 18o presses and compresses the felt sheet 16 between the O-ring 18o and the upper surface 23a of the cover inner flange portion 23, in the same manner as the protrusion portion 18s shown in Fig. 5 as the third embodiment. The diameter of the O-ring 18o is the same as the diameter of the top of the protrusion 18s shown in Fig. 5 as the third embodiment. The shape of the ring groove 18m is not particularly limited as long as the O-ring 18o can exhibit sealing properties as a pressing part.

[0096] The ring groove 18m and the O-ring 18o are continuously formed around the entire radial circumference of the output outer flange portion 18. The ring groove 18m and the O-ring 18o have a substantially equal radial cross-sectional shape around the entire circumference. The ring groove 18m has a substantially equal axial concave shape around the entire circumference. The O-ring 18o has a substantially equal axial convex shape around the entire circumference.

[0097] The ring groove 18m and the O-ring 18o are arranged such that the top of the O-ring 18o is located outside the inner circumferential end 23t of the cover inner flange portion 23 in the radial direction. The ring groove 18m and the O-ring 18o are arranged such that the top of the O-ring 18o is located outside the outer circumferential surface 14d of the output block body 14 in the radial direction. The ring groove 18m and the O-ring 18o are arranged such that the top of the O-ring 18o is located outside the inner circumferential end 16t of the felt sheet 16 in the radial direction.

[0098] The ring groove 18m and the O-ring 18o are arranged such that the top of the O-ring 18o is located on the inner side of the outer peripheral surface 18r of the output outer flange portion 18 in the radial direction. As a result, the ring groove 18m and the O-ring 18o are formed at a position facing the upper surface 23a of the cover inner flange portion 23.

[0099] The dimension by which the O-ring 18o protrudes from the ring groove 18m toward the upper surface 23a of the cover inner flange portion 23 can be set to be similar to the dimension by which the top of the protrusion portion 18s shown in Figure 5 as the third embodiment protrudes in the axial direction from the lower surface 18a. The O-ring 18o needs to have a hardness that allows it to press and compress the felt sheet 16. The dimension by which the O-ring 18o protrudes from the ring groove 18m toward the upper surface 23a of the cover inner flange portion 23 can be increased or decreased depending on the hardness of the O-ring 18o, that is, the degree of compression of the pressed felt sheet 16.

[0100] For this reason, in the fourth embodiment, the ring groove 18m and the O-ring 18o function in the same manner as the protrusion portion 18s in which the inclined surface 18f shown in Figure 5 as the third embodiment is a curved surface and the radially inner side is also the same curved surface. In the fourth embodiment, the O-ring 18o also functions as an original sealing member.

[0101] In the fourth embodiment, the bearing 3 and the ring gear 4 are attached to the base portion 2, and then the cover 15 is attached. The felt sheet 16, which is an annular plate, is placed on the cover inner flange portion 23. The O-ring 18o is placed in the ring groove 18m of the output block body 14. After that, the output block body 14 is attached to the ring gear 4 so that the outer peripheral surface 14d is within the inner peripheral end 16t of the annular felt sheet 16.

[0102] Alternatively, the bearing 3, the ring gear 4, and the cover 15 are attached to the base portion 2. Then, the O-ring 18o is placed in the ring groove 18m of the output block body 14. The annular felt sheet 16 is attached so that the inner peripheral end 16t contacts the outer peripheral surface 14d of the output block body 14, and the felt sheet 16 is combined with the output block body 14. The output block body 14, the O-ring 18o, and the felt sheet 16 are attached to the ring gear 4.

[0103] The fourth embodiment has the same effects as the first embodiment. In addition to the felt sheet 16, the O-ring 18o can improve the sealing performance.

[0104] [Fifth embodiment] Hereinafter, a fifth embodiment of the lubricant leakage prevention mechanism and gear mechanism according to the present invention will be described with reference to FIG. FIG. 7 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 301 according to the fifth embodiment.

[0105] <Leak prevention mechanism> As shown in Fig. 7, the leakage suppression mechanism 301 has a ball protrusion (pressing portion) 23s as a convex shape serving as a pressing portion. The ball protrusion 23s as a pressing portion locally compresses the felt sheet 16 more strongly than other portions. The ball protrusion 23s locally applies an axial thickness direction compressive force Pq1 shown in Fig. 13 described later, and strongly compresses the felt sheet 16. The ball protrusions 23s are formed so as to protrude in the axial direction from the upper surface 23a of the cover inner flange portion 23 toward the lower surface 18a of the output outer flange portion 18. The ball protrusions 23s are formed intermittently around the entire radial circumference of the cover inner flange portion 23, spaced apart from each other in the circumferential direction.

[0106] Each ball protrusion 23s is formed to protrude in the axial direction from the upper surface 23a of the cover inner flange portion 23 toward the lower surface 18a of the output outer flange portion 18 in a semispherical shape. That is, the top of the ball protrusion 23s as a pressing portion is formed as a curved surface. The curved surface here is smooth in both the circumferential and radial directions. The multiple ball protrusions 23s can all be formed to have the same axial height dimension protruding from the upper surface 23a of the cover inner flange portion 23. The multiple ball protrusions 23s can all be formed to have substantially the same outer surface shape on the upper surface 23a of the cover inner flange portion 23. Specifically, they can be formed on the upper surface 23a of the cover inner flange portion 23 like a welded ball.

[0107] The position of the apex of each of the plurality of ball projections 23s in the radial direction is the same as or slightly outward from the position of the apex of the protrusion 18s shown in FIG. 5 as the third embodiment. The top of the ball protrusion 23s is located radially outward from the inner peripheral end 23t of the cover inner flange portion 23. The top of the ball protrusion 23s is located radially outward from the outer peripheral surface 14d of the output block body 14. The top of the ball protrusion 23s is located radially outward from the inner peripheral end 16t of the felt sheet 16. The top of the ball protrusion 23s is located radially inward from the outer peripheral surface 18r of the output outer flange portion 18. As a result, the ball protrusion portion 23s is formed at a position facing the lower surface 18a of the output outer flange portion 18.

[0108] Each of the ball protrusions 23s locally compresses the felt sheet 16 more strongly, thereby blocking the leakage of the lubricant toward the outside. The leakage of the lubricant can be effectively suppressed in the immediate vicinity of the ring gear 4. The ball protrusions 23s are formed intermittently in the circumferential direction. This acts as a rotation stopper for the felt sheet 16 slid by the output outer flange portion 18. In other words, the cover inner flange portion 23 and the felt sheet 16 do not slide, but the output outer flange portion 18 and the felt sheet 16 slide. This makes it possible to efficiently suppress leakage of the lubricant radially outward toward the outside along the upper surface 23a of the cover inner flange portion 23. The ball protrusion 23s is integrally formed with the cover inner flange 23, thereby reducing the number of parts and improving sealing performance. The ball protrusion 23s can be formed more easily than the protrusion 18s shown in Fig. 5 as the third embodiment. This improves workability in the manufacturing process and reduces manufacturing costs.

[0109] In the fifth embodiment, the ball protrusions 23s are formed intermittently in the circumferential direction, but the ball protrusions 23s can also be formed as circumferentially continuous ridges on the upper surface 23a of the cover inner flange portion 23. In this case, the felt sheet 16 is compressed as a pressing portion to block the flow of lubricant moving in the axial direction from immediately adjacent (directly above) the ring gear 4 along the outer circumferential surface 14d of the output block body 14. The felt sheet 16 blocks the flow of lubricant moving radially outward along the upper surface 23a of the cover inner flange portion 23.

[0110] At the same time, it is possible to inhibit the flow of lubricant moving axially from immediately adjacent (directly above) the ring gear 4 along the outer peripheral surface 14d of the output block body 14. It is also possible to inhibit the flow of lubricant moving radially outward along the lower surface 18a of the output outer flange portion 18. In this case, it is preferable that the shape of the top portion serving as the pressing portion is smooth even in the circumferential direction so that it does not get caught on the felt sheet 16 and tear it.

[0111] The fifth embodiment provides the same effects as the first embodiment described above.

[0112] [Sixth embodiment] Hereinafter, a sixth embodiment of the lubricant leakage prevention mechanism and gear mechanism according to the present invention will be described with reference to FIG. FIG. 8 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism including a lubricant leakage prevention mechanism 301 according to the sixth embodiment.

[0113] <Leak prevention mechanism> As shown in Fig. 8, the leakage suppression mechanism 301 has a folded end portion (pressing portion) 23st as a convex shape serving as a pressing portion. The folded end portion 23st as a pressing portion locally compresses the felt sheet 16 more strongly than other portions. The folded end portion 23st locally applies an axial thickness direction compressive force Pq1 shown in Fig. 13 described later, and strongly compresses the felt sheet 16.

[0114] The folded end 23st is formed by folding back the inner peripheral end 23t of the cover inner flange portion 23 so as to protrude in the axial direction beyond the upper surface 23a toward the lower surface 18a of the output outer flange portion 18. The folded end 23st is formed continuously in the circumferential direction around the entire radial circumference of the cover inner flange portion 23.

[0115] The folded end 23st is formed so that the axial height dimension of the axial projection from the upper surface 23a of the cover inner flange portion 23 is substantially the same as the axial height dimension of the protruding portion 18s shown in FIG. 5 as the third embodiment of the present invention that protrudes from the lower surface 18a. The folded end 23st as the pressing portion has a curved apex. The curved surface here is smooth even in the radial direction.

[0116] The folded end 23st is formed continuously around the entire radial circumference of the cover inner flange portion 23. The folded end 23st has a substantially uniform radial cross-sectional shape around the entire circumference. The folded end 23st has a substantially uniform axial convex shape around the entire circumference. The apex of the folded end 23st in the radial direction substantially coincides with the inner peripheral end 23t of the cover inner flange portion 23. The apex of the folded end 23st in the radial direction is located outside the outer peripheral surface 14d of the output block body 14.

[0117] The apex of the folded end 23st is located radially outward from the inner circumferential end 16t of the felt sheet 16. The apex of the folded end 23st is located radially inward from the outer circumferential surface 18r of the output outer flange portion 18. The apex of the folded end 23st is located radially inward from the apex of the protrusion portion 18s shown in FIG. 5 as the third embodiment. As a result, the folded end portion 23st is formed at a position facing the lower surface 18a of the output outer flange portion 18.

[0118] The folded end 23st functions as a pressing portion and compresses the felt sheet 16, inhibiting the flow of lubricant moving axially from immediately adjacent (directly above) the ring gear 4 along the outer circumferential surface 14d of the output block body 14. The folded end 23st inhibits the flow of lubricant moving radially outward along the upper surface 23a of the cover inner flange portion 23. In particular, leakage of the lubricant can be suppressed before (upstream of) the lubricant reaches the upper surface 23a of the cover inner flange portion 23.

[0119] The sixth embodiment provides the same effects as the first embodiment described above.

[0120] Although the folded end 23st is formed continuously in the circumferential direction, it can also be formed intermittently in the circumferential direction, like the ball protrusion 23s. In this case, the folded end 23st functions as a rotation stopper for the felt sheet 16. In this case, it is preferable that the top shape as the pressing part is smooth in the circumferential direction as well, so that it does not get caught on the felt sheet 16 and tear it.

[0121] [Seventh embodiment] Hereinafter, a seventh embodiment of a lubricant leakage prevention mechanism and a gear mechanism according to the present invention will be described with reference to FIG. FIG. 9 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 301 according to the seventh embodiment.

[0122] <Leak prevention mechanism> As shown in Fig. 9, the leakage suppression mechanism 301 has a convex shape as a pressing part, which has a configuration equivalent to the protrusion 18s (pressing part) shown in Fig. 5 as the third embodiment and the ball protrusion 23s (pressing part) shown in Fig. 7 as the fifth embodiment. The protrusion 18s and the ball protrusion 23s as the pressing parts locally compress the felt sheet 16 more strongly than other parts. The protrusion 18s (pressing part) and the ball protrusion 23s (pressing part) locally apply an axial thickness direction compressive force Pq1 shown in Fig. 13 described later, and strongly compress the felt sheet 16.

[0123] The pressing portion has a ball protrusion 23s that protrudes in the axial direction from the upper surface 23a at the inner peripheral end 23t of the cover inner flange portion 23. The pressing portion has a protrusion 18s that protrudes in the axial direction from the lower surface 18a of the output outer flange portion 18. In other words, the protrusion 18s and the ball protrusion 23s protrude toward the felt sheet 16 in opposing directions, compressing it.

[0124] Moreover, the apex of the protrusion 18s is located radially outward from the outer peripheral surface 14d of the output block body 14. The apex of the protrusion 18s is located radially outward from the inner peripheral end 16t of the felt sheet 16. The apex of the protrusion 18s is located radially outward from the inner peripheral end 23t of the cover inner flange portion 23. The top of the ball protrusion 23s is located radially outward of the top of the protrusion 18s. The top of the ball protrusion 23s is located radially inward of the outer peripheral surface 18r of the output outer flange portion 18.

[0125] As a result, the protrusion 18s is formed at a position facing the upper surface 23a of the cover inner flange portion 23. The ball protrusion 23s is formed at a position facing the lower surface 18a of the output outer flange portion 18. Moreover, the protrusion 18s and the ball protrusion 23s are at different positions in the radial direction. Therefore, the felt sheet 16 is pressed and compressed in opposite directions at two points in the radial direction. Therefore, the flow of the lubricant moving radially outward can be obstructed at two points in the radial direction. Moreover, the ball projection 23s has its top located outside the inner circumferential end 16t of the felt sheet 16, and therefore functions as a rotation stopper for the felt sheet 16.

[0126] The seventh embodiment has the same effects as the first embodiment. The protrusion 18s presses the felt sheet 16 to suppress leakage of the lubricant along the lower surface 18a. The ball protrusion 23s presses the felt sheet 16 to efficiently suppress leakage of the lubricant along the upper surface 23a. At the same time, the ball protrusion 23s exerts a rotation prevention function for the felt sheet 16. Therefore, leakage of the lubricant along the upper surface 23a can be more efficiently suppressed. Therefore, the sealing performance of the felt sheet 16 can be further improved.

[0127] [Eighth embodiment] An eighth embodiment of the lubricant leakage prevention mechanism and gear mechanism according to the present invention will be described below with reference to Fig. 10 . FIG. 10 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 301 in this embodiment.

[0128] <Leak prevention mechanism> As shown in Fig. 10, the leakage suppression mechanism 301 is provided with an inclined surface (pressing portion) 18as in which the lower surface 18a of the output outer flange portion 18 is tapered rather than having a locally convex shape as a pressing portion. The inclined surface 18as as a pressing portion presses the felt sheet 16 so as to locally compress it more strongly at a portion closer to the outer peripheral surface 14d of the output block body 14 than at a portion closer to the outer peripheral surface 18r of the output outer flange portion 18. The inclined surface 18as as a pressing portion locally applies an axial thickness direction compressive force Pq1 shown in Fig. 13 described later to a portion closer to the outer peripheral surface 14d of the output block body 14 than at a portion closer to the outer peripheral surface 18r of the output outer flange portion 18, thereby compressing the felt sheet 16 more strongly.

[0129] The inclined surface 18as is inclined radially outward from the outer peripheral surface 14d of the output block body 14 to the outer peripheral surface 18r of the output outer flange portion 18. The inclined surface 18as is inclined from the outer side to the inner side in the radial direction so that the axial distance between the lower surface 18a of the output outer flange portion 18 and the upper surface 23a of the cover inner flange portion 23 becomes smaller. In other words, the force with which the inclined surface 18as compresses the felt sheet 16 gradually increases from the outer side to the inner side in the radial direction from the outer peripheral surface 18r to the inner peripheral end 23t. The force with which the inclined surface 18as compresses the felt sheet 16 in the axial direction is strongest at the position of the inner peripheral end 23t of the cover inner flange portion 23.

[0130] The axial distance between the lower surface 18a of the output outer flange portion 18 and the upper surface 23a of the cover inner flange portion 23 is determined by the inclination of the inclined surface 18as. However, at the position of the inner circumferential end portion 23t of the cover inner flange portion 23, which is the innermost portion, it is preferable that the axial distance be approximately the same as or smaller than the axial distance between the top of the protrusion portion 18s and the upper surface 23a shown in Fig. 5 as the third embodiment. Compared with the protrusion 18s shown in FIG. 5 as the third embodiment, the inclined surface 18as having a simple tapered shape can be easily manufactured and processed integrally with the output block body 14.

[0131] The eighth embodiment provides the same effects as the first embodiment described above. The inclined surface 18as is configured to be inclined radially outward from the outer peripheral surface 14d of the output block body 14 to the outer peripheral surface 18r of the output outer flange portion 18. However, the inclined surface 18as may be configured to be inclined toward the outer peripheral surface 18r from a position radially outer than the outer peripheral surface 14d. The inclined surface 18as may be configured to be inclined toward the outer peripheral surface 14d from a position radially inner than the outer peripheral surface 18r.

[0132] [Ninth embodiment] Hereinafter, a ninth embodiment of the lubricant leakage prevention mechanism and the gear mechanism according to the present invention will be described with reference to FIG. FIG. 11 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 301 according to the ninth embodiment.

[0133] <Leak prevention mechanism> As shown in FIG. 11, the leakage prevention mechanism 301 has, as a pressing portion, an inclined flange portion (pressing portion) 23A inside the cover that is inclined in the radial direction. The cover inner inclined flange portion (cover inner flange portion) 23A is inclined so that the inner side is closer to the lower surface 18a of the output outer flange portion 18 in the axial direction than the radial outer side. The cover inner inclined flange portion 23A is inclined so that the inner peripheral end portion 23At is closer to the lower surface 18a of the output outer flange portion 18 in the axial direction than the radial outer peripheral end portion 23Ae connected to the inner peripheral surface 31n of the cylindrical cover main body 31.

[0134] That is, the cover inner inclined flange portion 23A is inclined so that the axial distance between the inner peripheral end portion 23At and the lower surface 18a of the output outer flange portion 18 is smaller than the axial distance between the upper surface 23Aa of the cover inner inclined flange portion 23A and the outer peripheral surface 18r of the output outer flange portion 18. In this manner, the upper surface 23Aa of the cover inner inclined flange portion 23A forms a tapered surface. In the cover inner inclined flange portion 23A, the apex, which is the boundary between the upper surface 23Aa and the inner circumferential end portion 23At, is formed as a curved surface.

[0135] In the ninth embodiment, the upper surface 23Aa of the inclined flange portion 23A in the cover acts in the same manner as the inclined surface 18as as the pressing portion shown in FIG. 10 as the eighth embodiment. The inclined flange portion 23A in the cover presses the felt sheet 16 so that the portion close to the outer peripheral surface 14d of the output block body 14 locally compresses the felt sheet 16 most strongly. In other words, the force with which the upper surface 23Aa presses the felt sheet 16 between the lower surface 18a and the felt sheet 16 to compress it becomes larger toward the inside in the radial direction compared to the vicinity of the outer peripheral surface 18r. The force with which the upper surface 23Aa presses the felt sheet 16 between the lower surface 18a and the felt sheet 16 to compress it increases to be strongest at the inner peripheral end 23At. With the inclination of the upper surface 23Aa, the portion of the inclined flange portion 23A in the cover close to the outer peripheral surface 14d of the output block body 14 locally applies an axial thickness direction compressive force Pq1 shown in FIG. 13 described later. As a result, the inclined flange portion 23A in the cover strongly compresses the felt sheet 16.

[0136] The cover inner inclined flange portion 23A is connected and fixed at an incline relative to the inner peripheral surface 31n of the cylindrical cover main body 31 along the axial direction in correspondence with the inclination of the upper surface 23Aa. The cover inner inclined flange portion 23A has a constant thickness dimension in the radial direction, i.e., an axial dimension, from the outer peripheral end portion 23Ae to the inner peripheral end portion 23At. The thickness of the cover inner inclined flange portion 23A may vary in the radial direction from the outer peripheral end portion 23Ae to the inner peripheral end portion 23At.

[0137] An upper surface 23Aa of the cover inner inclined flange portion 23A is inclined as a tapered surface as shown in Fig. 11. That is, the upper surface 23Aa is inclined in a state in which the felt sheet 16 and the output block body 14 are assembled.

[0138] In this way, the upper surface 23Aa of the in-cover inclined flange portion 23A must be inclined as a tapered surface when the felt sheet 16 and the output block body 14 are assembled. In this case, the upper surface 23Aa of the in-cover inclined flange portion 23A can form a tapered surface inclined at an inclination angle equal to the inclination angle shown in FIG. 11 when the felt sheet 16 and the output block body 14 are not assembled.

[0139] When the felt sheet 16 and the output block body 14 are not attached, the upper surface 23Aa of the inclined flange portion 23A inside the cover can form a tapered surface inclined at a larger inclination angle than the inclination angle shown in Figure 11. In this case, the felt sheet 16 and the output block body 14 are assembled. As a result, the inclination angle at which the cover inner inclined flange portion 23A is connected to the cover main body 31 may be changed.

[0140] In this case, the cover inner inclined flange portion 23A elastically deforms relative to the cover main body 31 so as to curve from the outer peripheral end portion 23Ae. As a result, the pressing force compressing the felt sheet 16 is greatest near the inner peripheral end portion 23At. The elastic deformation of the cover inner inclined flange portion 23A relative to the cover main body 31 increases the compressive force of the felt sheet 16. As a result, the cover inner inclined flange portion 23A efficiently presses and compresses the felt sheet 16 as if it were an elastic member like a spring.

[0141] The outer peripheral end 23Ae of the cover inner inclined flange portion 23A connected to the inner peripheral surface 31n of the cover body 31 may be configured not to be inclined but to be curved in the axial direction toward the inside in the radial direction. In this case, the cover body 31 may be configured so that the upper surface 23Aa is concave. In this case, it is possible to increase the force that presses and compresses the felt sheet 16 near the inner circumferential end portion 23At, compared to a configuration that does not elastically deform.

[0142] In the ninth embodiment, leakage of the lubricant along the upper surface 23Aa can be more efficiently suppressed, and the sealing performance of the felt sheet 16 can be further improved.

[0143] [Tenth embodiment] A tenth embodiment of the lubricant leakage prevention mechanism and gear mechanism according to the present invention will now be described with reference to FIG. FIG. 12 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 301 according to the tenth embodiment.

[0144] <Leak prevention mechanism> As shown in Fig. 12, the leakage suppression mechanism 301 does not function as a pressing portion to locally compress the felt sheet 16 in the axial direction. The leakage suppression mechanism 301 compresses the felt sheet 16 in the radial direction along the lower surface 18a of the output outer flange portion 18. In other words, as shown in Fig. 12, the leakage suppression mechanism 301 does not function as a pressing portion to locally compress the felt sheet 16 with a convex shape or a tapered surface shape. The leakage suppression mechanism 301 includes an outer peripheral groove (pressing portion) 14m that is a concave shape that compresses the felt sheet 16 in the radial direction.

[0145] The outer circumferential groove 14m serving as a pressing portion is formed on the outer circumferential surface 14d of the output block body 14. The outer circumferential groove 14m is formed at a position close to the lower surface 18a in the axial direction of the outer circumferential surface 14d. The outer circumferential groove 14m is formed continuously around the entire circumference of the outer circumferential surface 14d. The outer circumferential groove 14m has a radial cross-sectional shape that is approximately uniform around the entire circumference of the outer circumferential surface 14d.

[0146] The radial depth dimension of the outer peripheral groove 14m is set as follows: The outer circumferential groove 14m is formed so that the sum of the dimension from the outer circumferential surface 14d of the output block body 14 to the outer circumferential end 23e connected to the inner circumferential surface 31n of the cover main body 31 and the radial depth dimension of the outer circumferential groove 14m is shorter than the radial dimension of the felt sheet 16 in an unassembled state. The radial dimension of the felt sheet 16 is the dimension from the inner circumferential end 16t to the outer circumferential end 16tr.

[0147] That is, the sum of the radial dimension of the cover inner flange portion 23, the radial distance between the inner peripheral end portion 23t and the outer peripheral surface 14d, and the radial depth dimension of the outer peripheral groove 14m is formed to be shorter than the radial dimension of the felt sheet 16 in an unassembled state. In other words, the sum of the radial dimension from the inner peripheral surface 31n of the cover main body 31 to the outer peripheral surface 14d of the output block body 14 and the radial depth dimension of the outer peripheral groove 14m is formed to be shorter than the radial dimension of the felt sheet 16 in an unassembled state.

[0148] The outer peripheral groove 14m is formed so that the radial opening width dimension is larger than the thickness dimension of the felt sheet 16 in an unassembled state. The radial opening width dimension of the outer peripheral groove 14m is a dimension into which the inner peripheral end 16t of the felt sheet 16 in an unassembled state can be inserted. The radial opening width dimension of the outer peripheral groove 14m is not particularly limited as long as the felt sheet 16 can maintain a shape along the upper surface 23a.

[0149] FIG. 13 is a perspective view illustrating the compressive force of the felt sheet 16. As shown in FIG. As shown in Fig. 13, an inner peripheral end 16t of a felt sheet 16 is housed in the outer peripheral groove 14m. The inner peripheral end 16t of the felt sheet 16 is in contact with the outer peripheral groove 14m. An outer peripheral end 16tr of the felt sheet 16 is in contact with an inner peripheral surface 31n of the cover body 31 at a position close to and above the upper surface 23a. The felt sheet 16 is present, extending in the radial direction along the upper surface 23a. The felt sheet 16 is sandwiched between the inner peripheral surface 31n and the radial surface of the outer peripheral groove 14m.

[0150] The unassembled felt sheet 16 is formed as an annular plate with a substantially uniform thickness. In this state, the radial width of the felt sheet 16, i.e., the width from the inner peripheral surface 31n of the cover body 31 to the radial surface of the outer peripheral groove 14m, is smaller than the width from the inner peripheral end 16t to the outer peripheral end 16tr of the felt sheet 16.

[0151] Due to these dimensional differences in the width direction, when the cover body 31 and the output block body 14 are assembled, a radial width direction compressive force Pq2 is applied to the felt sheet 16. When the cover body 31 and the output block body 14 are assembled, the felt sheet 16 is compressed in the radial direction by the radial width direction compressive force Pq2. At this time, the radial width direction compressive force Pq2 shown in Fig. 13 acts uniformly on the felt sheet 16 in the circumferential direction. The circumferential dimensions of the outer peripheral end 16tr and the inner peripheral end 16t of the felt sheet 16 are set so that the radial width direction compressive force Pq2 acts stronger at the inner peripheral end 16t than at the outer peripheral end 16tr of the felt sheet 16 in the radial direction.

[0152] In this way, the compressed felt sheet 16 can prevent the lubricant leaking out from between the inner peripheral end 23t and the outer peripheral surface 14d from seeping out further. In particular, due to the magnitude of the radial width direction compressive force Pq2 in the radial direction, the sealing performance of the felt sheet 16 is stronger at the inner peripheral end 16t than at the outer peripheral end 16tr. In other words, the radial width direction compressive force Pq2 acts so as to locally compress the felt sheet 16 more strongly in the portion close to the outer peripheral surface 14d of the output block body 14 than in the portion close to the outer peripheral surface 18r of the output outer flange portion 18. This makes it possible to suppress leakage of the lubricant before it reaches the upper surface 23a of the cover inner flange portion 23 (upstream).

[0153] In the tenth embodiment, the axial thickness direction compressive force Pq1 shown in Fig. 13 is not applied to the felt sheet 16. However, the felt sheet 16 can exhibit a sealing property along the upper surface 23a. In the tenth embodiment, leakage of the lubricant can be suppressed before (upstream of) the lower surface 18a. For this reason, the felt sheet 16 may be in contact with the lower surface 18a, but may not be in contact with the lower surface 18a.

[0154] The tenth embodiment provides the same effects as the first embodiment described above.

[0155] [Eleventh embodiment] Hereinafter, an eleventh embodiment of a lubricant leakage prevention mechanism and a gear mechanism according to the present invention will be described with reference to FIG. FIG. 14 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 301 according to the eleventh embodiment.

[0156] <Leak prevention mechanism> As shown in FIG. 14, the leakage suppression mechanism 301 has a lower circumferential groove (pressing portion) 18m formed on the lower surface 18a of the output outer flange portion 18 as a pressing portion, and a configuration similar to the folded end portion (pressing portion) 23st shown in FIG. 8 as the sixth embodiment. The leakage suppression mechanism 301 does not function as a pressing portion to apply an axial thickness direction compressive force Pq1 to the felt sheet 16. The leakage suppression mechanism 301 functions as a pressing portion to apply a radial width direction compressive force Pq2 shown in FIG.

[0157] The lower circumferential groove 18m opens axially downward on the lower surface 18a. The lower circumferential groove 18m opens at a position facing the lower surface 18a. The lower circumferential groove 18m is formed on the entire circumference of the lower surface 18a, which is radially outer than the outer circumferential surface 14d. The lower circumferential groove 18m is formed radially outward from the outer circumferential surface 14d at a distance therefrom. The lower circumferential groove 18m is formed on the entire circumference of the lower surface 18a, which is radially inner than the outer circumferential surface 18r. The lower circumferential groove 18m is formed radially inward from the outer circumferential surface 18r at a distance therefrom.

[0158] The lower circumferential groove 18m is formed on the entire circumference of the lower surface 18a, which is radially outward of the folded end 23st. The inner peripheral wall surface of the lower circumferential groove 18m is formed at a position that coincides with the outer peripheral wall surface of the folded end 23st in the radial direction. In other words, the inner peripheral wall surface of the lower circumferential groove 18m forms a cylindrical surface that is approximately flush with the outer peripheral wall surface of the folded end 23st in the axial direction. The axial distance between the inner peripheral wall surface of the lower circumferential groove 18m and the outer peripheral wall surface of the turned-up end 23st is equal to the axial distance between the lower surface 18a and the turned-up end 23st.

[0159] As long as the inner peripheral wall surface of the lower circumferential groove 18m and the outer peripheral wall surface of the turned-back end 23st are flush with each other, the inner peripheral wall surface of the lower circumferential groove 18m and the outer peripheral wall surface of the turned-back end 23st may not be configured to be aligned along the axial direction. In other words, the inner peripheral wall surface of the lower circumferential groove 18m and the outer peripheral wall surface of the turned-back end 23st may be configured to be flush with each other, with the upper surface 23a being larger in diameter in the radial direction than the lower surface 18a.

[0160] The lower circumferential groove 18m is formed so that the radial opening width dimension is larger than the thickness dimension of the unassembled felt sheet 16. The radial opening width dimension of the lower circumferential groove 18m is not particularly limited as long as the inner circumferential end 16t of the unassembled felt sheet 16 can be inserted therein.

[0161] The inner peripheral end 16t of the felt sheet 16 abuts against and is in contact with the upper surface of the lower circumferential groove 18m. The outer peripheral end 16tr of the felt sheet 16 abuts against and is in contact with the inner peripheral surface 31n of the cover body 31. The portion of the felt sheet 16 adjacent to the outer peripheral end 16tr extends along the upper surface 23a. The portion of the felt sheet 16 adjacent to the outer peripheral end 16tr extends radially along the upper surface 23a.

[0162] A portion of the felt sheet 16 adjacent to the inner peripheral end 16t is present and extends in the axial direction along the inner peripheral wall surface of the lower circumferential groove 18m and the outer peripheral wall surface of the folded end 23st. In other words, the felt sheet 16 is curved from the inner peripheral end 16t to the outer peripheral end 16tr. Here, the radial dimension of the felt sheet 16 in the assembled state is the dimension of the curved felt sheet 16 from the inner peripheral end 16t to the outer peripheral end 16tr.

[0163] The lower circumferential groove 18m is formed so that the axial depth dimension is as follows. The axial depth dimension of the lower circumferential groove 18m is determined so that the sum of the distance between the upper surface of the lower circumferential groove 18m and the upper surface 23a and the distance between the base end of the folded end 23st and the inner circumferential surface 31n of the cover main body 31 is shorter than the radial dimension of the felt sheet 16 in an unassembled state. In other words, the sum of the radial dimension of the upper surface 23a of the cover inner flange portion 23, the axial height dimension of the folded end 23st, the axial distance between the folded end 23st and the lower surface 18a, and the axial depth dimension of the lower circumferential groove 18m is the compressed dimension of the felt sheet 16. This compressed dimension is shorter than the radial dimension of the felt sheet 16 in an unassembled state.

[0164] In other words, the sum of the radial dimension from the inner surface 31n of the cover body 31 to the outer surface of the folded end 23st, the axial distance from the upper surface 23a to the lower surface 18a, and the axial depth dimension of the lower circumferential groove 18m is shorter than the radial dimension of the felt sheet 16 in an unassembled state.

[0165] Due to these dimensional differences, when the cover body 31 and the output block body 14 are assembled, a radial width direction compressive force Pq2 is applied to the felt sheet 16, even though it is in a curved state. When the cover body 31 and the output block body 14 are assembled, the felt sheet 16 is compressed in the radial direction in a curved state by the radial width direction compressive force Pq2. At this time, the radial width direction compressive force Pq2 shown in FIG. 13 acts uniformly in the circumferential direction on the curved felt sheet 16. In the radial direction, the radial width direction compressive force Pq2 acts stronger at the inner circumferential end 16t of the curved felt sheet 16 than at the outer circumferential end 16tr.

[0166] In this way, the compressed felt sheet 16 can prevent the lubricant leaking out from between the folded end 23st and the outer circumferential surface 14d from seeping out further. In particular, due to the magnitude of the radial width direction compressive force Pq2 in the radial direction, the sealing performance of the felt sheet 16 is stronger at the inner circumferential end 16t than at the outer circumferential end 16tr. In other words, the radial width direction compressive force Pq2 acts so as to locally compress the felt sheet 16 more strongly at the lower circumferential groove 18m that is closer to the outer circumferential surface 14d of the output block body 14 than at the portion that is closer to the outer circumferential surface 18r of the output outer flange portion 18.

[0167] Moreover, the radial width direction compressive force Pq2 acts in the radial direction of the felt sheet 16 in an unassembled state. In an assembled state, the radial width direction compressive force Pq2 acts in the axial direction from the upper surface of the lower circumferential groove 18m to the inner peripheral end 16t of the felt sheet 16. At the same time, the vicinity of the inner peripheral end 16t of the felt sheet 16 is curved by the folded end 23st and pressed against the upper surface 23a.

[0168] That is, the inner peripheral end 16t of the felt sheet 16 is pressed against the upper surface of the lower circumferential groove 18m, and the curved portion is pressed against the upper surface 23a. This provides sealing in the axial direction from the lower surface 18a to the upper surface 23a. As a result, leakage of the lubricant along the upper surface 23a and leakage of the lubricant along the lower surface 18a before reaching the upper surface 23a of the cover inner flange portion 23 (upstream) can be simultaneously and further suppressed.

[0169] The eleventh embodiment provides the same effects as the first embodiment described above.

[0170] [Twelfth embodiment] A lubricant leakage prevention mechanism and a gear mechanism according to a twelfth embodiment of the present invention will now be described with reference to Figs. FIG. 15 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 301 according to the twelfth embodiment. FIG. 16 is a perspective view illustrating a compressive force on a cylindrical felt sheet 16A. The twelfth embodiment differs from the above-described first to eleventh embodiments in terms of the seal member and the pressing portion (the same applies to the following thirteenth embodiment).

[0171] <Leak prevention mechanism> 15 and 16, the leakage prevention mechanism 301 uses a cylindrical felt sheet 16A as a sealing member. The leakage prevention mechanism 301 includes an outer peripheral surface (pressing portion) 18r and a lower surface (pressing portion) 18a of the output outer flange portion 18 as a pressing portion. The felt sheet 16A is made of the same material as the felt sheet 16 in the first to eleventh embodiments described above, and is configured to exhibit the same sealing properties.

[0172] The felt sheet 16A in an unassembled state has a generally cylindrical outer shape as shown in Fig. 16. The felt sheet 16A in an unassembled state can be a cylinder of generally uniform thickness and generally uniform diameter in the axial direction. The felt sheet 16A in an unassembled state has an axial dimension that is slightly larger than the axial dimension of the outer peripheral surface 18r of the output outer flange portion 18.

[0173] As shown in FIG. 15, the felt sheet 16A is disposed along the outer peripheral surface 18r of the output outer flange portion 18. The felt sheet 16A is fitted to the outer periphery of the outer peripheral surface 18r of the output outer flange portion 18. The inner peripheral surface 16Ab of the felt sheet 16A is in contact with the outer periphery of the outer peripheral surface 18r of the output outer flange portion 18. The felt sheet 16A is disposed between the inner peripheral surface 31n and the outer peripheral surface 18r of the cylindrical cover main body 31. The outer peripheral surface 16Aa of the felt sheet 16A may or may not be in contact with the inner peripheral surface 31n. In the cylindrical felt sheet 16A, the radial dimension is the thickness dimension, and the axial dimension is the width dimension.

[0174] The inner peripheral surface 16Ab of the felt sheet 16A has an inner diameter equal to the outer peripheral surface 18r of the output outer flange portion 18. The felt sheet 16A has an axial dimension larger than the outer peripheral surface 18r of the output outer flange portion 18. One end 16At of the felt sheet 16A protrudes from the outer peripheral surface 18r of the output outer flange portion 18 toward the upper surface 23a of the cover inner flange portion 23. The other end 16Atr of the felt sheet 16A is disposed flush with the upper end 31b, which is the end face of the cover main body 31, in the axial direction. The other end 16Atr of the felt sheet 16A is fixed to the outer peripheral surface 18r of the output outer flange portion 18.

[0175] The other end 16Atr of the felt sheet 16A may be disposed flush in the axial direction with the upper surface 14b, which is the end face of the output outer flange portion 18. The other end 16Atr of the felt sheet 16A may be located closer to the upper surface 23a than the upper end 31b of the cover body 31, as long as it does not protrude from the upper surface 14b in the axial direction and is located closer to the upper surface 23a than the upper surface 14b.

[0176] The vicinity of one end 16At of the assembled felt sheet 16A is bent from the outer peripheral surface 18r of the output outer flange portion 18 toward the lower surface 18a. In the vicinity of one end 16At of the assembled felt sheet 16A, the inner peripheral surface 16Ab is bent from the axial direction in contact with the outer peripheral surface 18r to the radially inward direction in contact with the lower surface 18a. In the vicinity of one end 16At of the assembled felt sheet 16A, the cross section is bent into an L-shape. In the vicinity of one end 16At of the assembled felt sheet 16A, the inner peripheral surface 16Ab is curved from the axial direction along the outer peripheral surface 18r to the radially inward direction along the lower surface 18a.

[0177] The vicinity of one end 16At of the assembled felt sheet 16A is in contact with the outer peripheral surface 16Aa along the upper surface 23a. The vicinity of one end 16At of the assembled felt sheet 16A is sandwiched between the lower surface 18a near the outer peripheral surface 18r and the upper surface 23a.

[0178] The felt sheet 16A is compressed near the boundary between the outer peripheral surface 18r and the lower surface 18a by being folded. In other words, the curved portion of the assembled felt sheet 16A is compressed. The felt sheet 16A sandwiched between the lower surface 18a and the upper surface 23a near the outer peripheral surface 18r is compressed. In this case, a radial / thickness direction compressive force Pq3 is applied to the felt sheet 16A as shown in Fig. 16. In other words, the cylindrical felt sheet 16A is compressed in the thickness direction.

[0179] The outer peripheral surface 18r, the lower surface 18a, and the upper surface 23a act as pressing parts. The inner peripheral surface 31n can also act as pressing parts. Alternatively, an axial width direction compressive force Pq4 can act on the bent felt sheet 16A. This makes it possible to suppress leakage of the lubricant before it reaches the inner circumferential surface 31n of the cover body 31 (upstream).

[0180] The twelfth embodiment provides the same effects as the first embodiment described above.

[0181] [Thirteenth embodiment] Hereinafter, a lubricant leakage prevention mechanism and a gear mechanism according to a thirteenth embodiment of the present invention will be described with reference to FIG. Fig. 17 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 301 in this embodiment. Unlike the twelfth embodiment shown in Fig. 15, the leakage prevention mechanism 301 does not apply a radial thickness direction compressive force Pq3 to a cylindrical felt sheet 16A as a pressing part. The leakage prevention mechanism 301 applies an axial width direction compressive force Pq4 shown in Fig. 16 to the felt sheet 16A as a pressing part.

[0182] <Leak prevention mechanism> As shown in Fig. 17, the leakage prevention mechanism 301 uses a cylindrical felt sheet 16A as a sealing member, similar to that of the twelfth embodiment shown in Fig. 15. The leakage prevention mechanism 301 has an outer circumferential groove (pressing portion) 18rm formed on the outer circumferential surface 18r of the output outer flange portion 18 as a pressing portion, in addition to the vicinity of the outer circumferential surface (pressing portion) 18r and the lower surface (pressing portion) 18a as the pressing portion, similar to those of the twelfth embodiment shown in Fig. 15. The leakage prevention mechanism 301 has a folded end portion (pressing portion) 23st of the cover inner flange portion 23.

[0183] The outer circumferential groove 18rm is formed on the outer circumferential surface 18r of the output outer flange portion 18. The outer circumferential groove 18rm opens radially outward on the outer circumferential surface 18r. The outer circumferential groove 18rm opens at a position facing the inner circumferential surface 31n. The outer circumferential groove 18rm is formed continuously around the entire circumference of the outer circumferential surface 18r. The outer circumferential groove 18rm is formed on the outer circumferential surface 18r, spaced apart from the lower surface 18a in the axial direction. The outer circumferential groove 18rm is formed on the outer circumferential surface 18r, spaced apart from the upper surface 14b, which is the end face of the output outer flange portion 18, in the axial direction.

[0184] The outer circumferential groove 18rm is formed on the outer circumferential surface 18r at a position closer to the upper surface 23a than the upper end 31b of the cover body 31. The outer circumferential groove 18rm is formed on the outer circumferential surface 18r at a position closer to the upper end 31b of the cover body 31 than the upper surface 23a ... The opening width dimension in the axial direction of the outer circumferential groove 18rm only needs to be larger than the diameter and thickness dimension of the other end 16Atr of the felt sheet 16A so that the other end 16Atr of the felt sheet 16A can be accommodated therein.

[0185] The other end 16Atr of the felt sheet 16A is housed in the outer circumferential groove 18rm. The other end 16Atr of the felt sheet 16A abuts against and is in contact with the peripheral bottom surface of the peripheral groove 18rm. The portion of the felt sheet 16A adjacent to the other end 16Atr inside the opening of the outer circumferential groove 18rm extends radially outward. The portion of the felt sheet 16A adjacent to the other end 16Atr curves from a position along the lower inner wall surface of the outer circumferential groove 18rm along the inner circumferential surface 31n and the outer circumferential surface 18r. The portion of the felt sheet 16A adjacent to the other end 16Atr curves from the other end 16Atr toward the one end 16At from the radial direction to the axial direction. The portion of the felt sheet 16A between the other end 16Atr and the one end 16At radially outside the opening of the outer circumferential groove 18rm curves toward the upper surface 23a.

[0186] The portion of the felt sheet 16A between the other end 16Atr and one end 16At, radially outward of the outer peripheral surface 18r, extends axially from the other end 16Atr toward the one end 16At along the inner peripheral surface 31n and the outer peripheral surface 18r. The portion of the felt sheet 16A close to the other end 16Atr, radially outward of the opening of the outer peripheral groove 18rm, extends axially along the inner peripheral surface 31n toward the upper surface 23a.

[0187] In the portion between the other end 16Atr and one end 16At of the felt sheet 16A, the outer peripheral surface 16Aa is in contact with the inner peripheral surface 31n of the cover body 31, radially outward from the opening of the outer peripheral groove 18rm. In the portion where the outer peripheral surface 16Aa of the felt sheet 16A is in contact with the inner peripheral surface 31n, the inner peripheral surface 16Ab of the felt sheet 16A may or may not be in contact with the outer peripheral surface 18r. In this manner, the portion of the felt sheet 16A between the other end 16Atr and the one end 16At extends along the inner circumferential surface 31n of the cover body 31 in the axial direction.

[0188] The felt sheet 16A is curved from the other end 16Atr toward the one end 16At at the boundary between the outer peripheral surface 18r and the lower surface 18a. The portion of the felt sheet 16A between the other end 16Atr and the one end 16At is curved radially inward along the upper surface 23a. The portion of the felt sheet 16A adjacent to the one end 16At extends radially inward along the upper surface 23a. The portion of the felt sheet 16A adjacent to the one end 16At is curved from the other end 16Atr toward the one end 16At from the axial direction toward the radial direction.

[0189] One end 16At of the felt sheet 16A abuts against and contacts the outer peripheral surface of the folded end 23st. The vicinity of the one end 16At of the felt sheet 16A is sandwiched between the lower surface 18a of the output outer flange portion 18 and the upper surface 23a of the cover inner flange portion 23.

[0190] That is, the felt sheet 16A is curved inward at two points from the other end 16Atr to the one end 16At. The felt sheet 16A is curved at two points so that both 16Ab are recessed. The felt sheet 16A is curved so that the cross section in the radial and axial directions is approximately C-shaped. Here, the axial width direction dimension of the felt sheet 16A in the assembled state is defined as the dimension along the curved felt sheet 16A from one end 16At to the other end 16Atr.

[0191] The outer peripheral groove 18rm is formed so that the dimension from the circumferential bottom surface of the outer peripheral groove 18rm to the outer peripheral surface of the folded end 23st is smaller than the axial width dimension of the felt sheet 16A in an unassembled state. In other words, the radial depth dimension of the outer peripheral groove 18rm is determined so that the sum of the distance from the circumferential bottom surface of the outer peripheral groove 18rm to the outer peripheral surface 18r of the output outer flange portion 18 and the inner peripheral surface 31n of the cover body 31, and the creeping distance from the radial outside of the outer peripheral groove 18rm to directly above the folded end 23st is smaller than the axial width dimension of the felt sheet 16A in an unassembled state.

[0192] In other words, the outer peripheral groove 18rm is formed so that the C-shaped curved felt sheet 16A has a radial depth dimension that is compressed in the axial width direction compared to the felt sheet 16A in an unassembled state. At this time, the radial dimension of the cover inner flange portion 23 from the outer peripheral end portion 23e connected to the inner peripheral surface 31n to the folded-back end portion 23st and the formation position of the outer peripheral groove 18rm in the axial direction of the outer peripheral surface 18r can be taken into consideration.

[0193] Due to these widthwise dimensional differences, when the cover body 31 and the output block body 14 are assembled, an axial width direction compressive force Pq4 is applied to the curved felt sheet 16A. When the cover body 31 and the output block body 14 are assembled, the felt sheet 16A is compressed by the axial width direction compressive force Pq4. At this time, the axial width direction compressive force Pq4 shown in Fig. 16 acts uniformly on the felt sheet 16A in the circumferential direction. The axial width direction compressive force Pq4 acts with the same strength on the other end 16Atr and one end 16At of the felt sheet 16A, which are located at the same radial position.

[0194] When the cover body 31 and the output block body 14 are assembled, a radial thickness direction compressive force Pq3 is applied to the curved felt sheet 16A on the radial outside of the opening of the outer circumferential groove 18rm. Similarly, a radial thickness direction compressive force Pq3 is applied to the curved felt sheet 16A from the inner circumferential surface 31n along the upper surface 23a. Therefore, when the cover body 31 and the output block body 14 are assembled, the felt sheet 16A is compressed at two points by the radial thickness direction compressive force Pq3. At this time, the radial thickness direction compressive force Pq3 shown in FIG. 16 acts uniformly on the felt sheet 16A in the circumferential direction. The radial thickness direction compressive force Pq3 acts with the same strength at two curved positions because the felt sheet 16A is curved at the same position in the radial direction.

[0195] In this way, the compressed felt sheet 16A can prevent the lubricant leaking out from between the folded end 23st and the outer circumferential surface 14d from seeping out further. In particular, the compression by the axial width direction compressive force Pq4 and the compression at two locations by the radial thickness direction compressive force Pq3 act simultaneously. Therefore, the sealing property of the felt sheet 16A is stronger than when there is only compression by the axial width direction compressive force Pq4 or when there is only one stage of compression by the radial thickness direction compressive force Pq3. This makes it possible to suppress leakage of the lubricant before it reaches the upper end 31b of the cover body 31 (upstream).

[0196] The sealing in the thirteenth embodiment is achieved solely by compression of the curved felt sheet 16A caused by the axial width direction compressive force Pq4 and the radial thickness direction compressive force Pq3. The mechanism is different from that of the leakage suppression mechanism in which the felt sheet 16A is sandwiched between the inner peripheral surface 31n of the cover body 31 and the outer peripheral surface 18r of the output outer flange portion 18, which face each other in the radial direction.

[0197] The thirteenth embodiment provides the same effects as the first embodiment described above.

[0198] [Fourteenth embodiment] Hereinafter, a lubricant leakage prevention mechanism and a gear mechanism according to a fourteenth embodiment of the present invention will be described with reference to FIG. FIG. 18 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 401 in this embodiment. The fourteenth embodiment differs from the first to thirteenth embodiments described above in terms of the pressing direction of the sheet member.

[0199] <Leak prevention mechanism> The leakage suppression mechanism 401 uses a cylindrical felt sheet 16A as a sealing member. 18, the leakage prevention mechanism 401 has the inner circumferential surface 31n of the cover body 31 and the outer circumferential surface 18r of the output outer flange portion 18 opposed in the radial direction. The leakage prevention mechanism 401 holds the felt sheet 16A between the inner circumferential surface 31n of the cover body 31 and the outer circumferential surface 18r of the output outer flange portion 18 in the radial direction. An upper end 31b of the cover body 31 is flush with an upper surface 14b of the output block 14 in the axial direction. The other end 16Atr of the felt sheet 16A is flush with an upper surface 14b of the output block 14 in the axial direction.

[0200] A radial compression force Pq3 is applied to the felt sheet 16A by being sandwiched between the inner peripheral surface 31n of the cover body 31 and the outer peripheral surface 18r of the output outer flange portion 18. The felt sheet 16A is compressed by the radial compression force Pq3 and exhibits a sealing function. One end 16At of the felt sheet 16A abuts against the cover inner flange portion 23, but the axial width direction compressive force Pq4 is not acting on the felt sheet 16A.

[0201] The fourteenth embodiment provides the same effects as the first embodiment described above.

[0202] [Fifteenth embodiment] Hereinafter, a fifteenth embodiment of the lubricant leakage prevention mechanism and the gear mechanism according to the present invention will be described with reference to FIG. FIG. 19 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 401 in this embodiment. This embodiment differs from the above-described fourteenth embodiment in terms of the outer peripheral protrusion 18rs.

[0203] <Leak prevention mechanism> The leakage suppression mechanism 401 uses a cylindrical felt sheet 16A as a sealing member, similar to the fourteenth embodiment shown in FIG. 19, the leakage suppression mechanism 401 is formed with an outer peripheral protrusion portion (pressing portion) 18rs as a pressing portion. The outer peripheral protrusion portion 18rs as a pressing portion improves the sealing performance between the output block body 14 and the cover 15. The pressing portion locally presses and compresses the felt sheet 16A that is in surface contact between the output block body 14 and the cover 15.

[0204] In the 14th embodiment shown in FIG. 18, the radial distance between the inner peripheral surface 31n of the cover body 31 and the outer peripheral surface 18r of the output outer flange portion 18, which is in the left-right direction in the figure, is formed to be approximately equal over the entire length in the circumferential and axial directions. In contrast, in the outer peripheral protrusion portion 18rs of the 15th embodiment, as shown in FIG. 19, the axial distance is small even in the portion where the inner peripheral surface 31n and the outer peripheral surface 18r are in surface contact with the felt sheet 16A. In other words, in the area in surface contact with the felt sheet 16A, the outer peripheral protrusion portion 18rs as a pressing portion locally compresses the felt sheet 16A more strongly than other portions. The outer peripheral protrusion portion 18rs locally applies the radial thickness direction compressive force Pq3 shown in FIG. 16 to strongly compress the felt sheet 16A.

[0205] The outer peripheral protrusion 18rs is formed on the outer peripheral surface 18r of the output outer flange portion 18. The outer peripheral protrusion 18rs protrudes radially outward from the outer peripheral surface 18r. The outer peripheral protrusion 18rs protrudes at a position facing the inner peripheral surface 31n. The outer peripheral protrusion 18rs is formed continuously around the entire circumference of the outer peripheral surface 18r. The outer peripheral protrusion 18rs is formed on the outer peripheral surface 18r at a distance from the lower surface 18a in the axial direction. The outer peripheral protrusion 18rs is formed on the outer peripheral surface 18r in contact with the upper surface 14b, which is the end surface of the output outer flange portion 18 in the axial direction. The outer peripheral protrusion 18rs may be formed on the outer peripheral surface 18r at a distance from the upper surface 14b, which is the end surface of the output outer flange portion 18 in the axial direction.

[0206] The outer peripheral protrusion 18rs is formed on the outer peripheral surface 18r at a position spaced from the upper surface 23a near the upper end 31b of the cover body 31. The outer peripheral protrusion 18rs may be formed on the outer peripheral surface 18r at a position spaced from the upper end 31b of the cover body 31. The outer peripheral protrusion 18rs is formed on the outer peripheral surface 18r at a position spaced from the upper surface 23a. The outer peripheral protrusion 18rs is formed on the outer peripheral surface 18r at a position closer to the upper end 31b of the cover body 31 than the upper surface 23a. The outer peripheral protrusion 18rs may be formed on the outer peripheral surface 18r at a position closer to the upper surface 23a.

[0207] The outer peripheral protrusion portion 18rs may have an inclined surface that continues from its top to the outer peripheral surface 18r of the output outer flange portion 18. The outer peripheral protrusion portion 18rs may have an annular surface that rises radially from its top to the outer peripheral surface 18r of the output outer flange portion 18. The outer peripheral protrusion 18rs is formed so that its top portion is a rounded surface. The rounded surface of the top portion of the outer peripheral protrusion 18rs is a curved surface having a radius of curvature in a radial cross section. The top portion of the outer peripheral protrusion 18rs is also formed to have a smooth shape in the circumferential direction.

[0208] The radial distance between the top of the outer circumferential protrusion 18rs and the inner circumferential surface 31n of the cover body 31 is smaller than the thickness dimension of the felt sheet 16A in an unassembled state. At a circumferential position different from the outer peripheral protrusion portion 18rs, the radial distance between the output outer flange portion 18 and the inner peripheral surface 31n of the cover body 31 may be smaller than the thickness dimension of the felt sheet 16A in an unassembled state, or may be slightly larger.

[0209] The felt sheet 16A is sandwiched between the inner peripheral surface 31n of the cover body 31 and the outer peripheral surface 18r of the output outer flange portion 18, and a radial thickness direction compressive force Pq3 shown in Fig. 16 is applied to the felt sheet 16A. The felt sheet 16A is compressed by this radial thickness direction compressive force Pq3, and exhibits a sealing function. A large radial thickness direction compressive force Pq3 is locally applied to the felt sheet 16A by the outer peripheral protrusions 18rs in the radial direction. The felt sheet 16A is locally compressed in the radial direction by the outer peripheral protrusions 18rs.

[0210] These obstruct the flow of lubricant used for meshing of the pinion 27 with the ring gear 4 from immediately adjacent (directly above) the ring gear 4 in the axial direction along the outer peripheral surface 14d of the output block body 14. The lubricant moves radially outward along the underside 18a of the output outer flange portion 18, obstructing the flow of lubricant moving axially upward along the outer peripheral surface 18r of the output outer flange portion 18. At the same time, the flow of lubricant moving axially outward from immediately adjacent (directly above) the ring gear 4 along between the outer peripheral surface 18r of the output outer flange portion 18 and the inner peripheral surface 31n of the cover body 31 is obstructed.

[0211] The outer peripheral protrusions 18rs can prevent the lubricant from soaking into the felt sheet 16A and leaking outward. The outer peripheral protrusions 18rs locally compress the felt sheet 16 more strongly, thereby blocking the leakage of the lubricant to the outside. One end 16At of the felt sheet 16A abuts against the cover inner flange portion 23, but the axial width direction compressive force Pq4 shown in FIG. 16 is not acting on the felt sheet 16A.

[0212] The fifteenth embodiment provides the same effects as the first embodiment described above.

[0213] [Sixteenth embodiment] A lubricant leakage prevention mechanism and a gear mechanism according to a sixteenth embodiment of the present invention will be described below with reference to FIG. FIG. 20 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 401 in this embodiment. This embodiment differs from the above-described fourteenth embodiment in terms of the inner peripheral ball protrusion 31s.

[0214] <Leak prevention mechanism> As shown in Fig. 20, the lubricant leakage suppression mechanism 401 has an inner circumferential ball protrusion (pressing portion) 31s as a convex shape serving as a pressing portion. The inner circumferential ball protrusion 31s as a pressing portion locally compresses the felt sheet 16A more strongly than other portions. The inner circumferential ball protrusion 31s locally applies a radial thickness direction compressive force Pq3 shown in Fig. 16 to strongly compress the felt sheet 16A. The inner peripheral ball protrusions 31s are formed so as to protrude axially inward from the inner peripheral surface 31n of the cover body 31 toward the outer peripheral surface 18r of the output outer flange portion 18. The inner peripheral ball protrusions 31s are formed intermittently around the entire radial circumference of the cover body 31, spaced apart from each other in the circumferential direction.

[0215] Each inner peripheral ball protrusion 31s is formed so as to protrude inward in the axial direction from the inner peripheral surface 31n of the cover body 31 toward the outer peripheral surface 18r of the output outer flange portion 18 in a semispherical shape. In other words, the inner peripheral ball protrusion 31s as a pressing portion has a curved apex. The curved surface here is smooth in both the circumferential and radial directions. The multiple inner peripheral ball protrusions 31s can all be formed to have the same radial height dimension protruding from the inner peripheral surface 31n of the cover body 31. The multiple inner peripheral ball protrusions 31s can all be formed on the inner peripheral surface 31n of the cover body 31 to have substantially the same outer surface shape. Specifically, they can be formed on the inner peripheral surface 31n of the cover body 31 like a welded ball.

[0216] The inner ball protrusions 31s all have the same apex position in the axial direction. The inner ball protrusions 31s may have apex positions slightly offset from each other in the axial direction as long as the apex positions are within a predetermined range. The top of the inner peripheral ball protrusion 31s is located axially below the upper end 31b of the cover body 31. The top of the inner peripheral ball protrusion 31s is located axially above the lower surface 18a of the output outer flange portion 18. The top of the inner peripheral ball protrusion 31s is located radially above the inner peripheral end 16t of the felt sheet 16. The inner peripheral ball projection 31s is formed in a range in which its top portion faces the outer peripheral surface 18r of the output outer flange portion 18 in the axial direction.

[0217] Each of the inner circumferential ball protrusions 31s applies a large radial thickness direction compressive force Pq3 locally to the felt sheet 16A in the radial direction. The felt sheet 16A is locally compressed more strongly by the inner circumferential ball protrusions 31s. This blocks the leakage of the lubricant toward the outside. The leakage of the lubricant can be efficiently suppressed in the immediate vicinity of the annular gear 4. The inner peripheral ball protrusions 31s are formed discontinuously in the circumferential direction, and therefore act as a rotation stopper for the felt sheet 16A which tends to slide between the output outer flange portion 18 and the cover body 31.

[0218] In other words, the cover body 31 and the felt sheet 16A do not slide, but the output outer flange portion 18 and the felt sheet 16A slide. This makes it possible to efficiently suppress leakage of the lubricant axially upward toward the outside along the inner circumferential surface 31n of the cover body 31. The inner peripheral ball protrusion 31s is integrally formed with the cover body 31, thereby improving sealing performance while reducing the number of parts. The inner peripheral ball protrusion 31s can be formed more easily than the outer peripheral protrusion 18rs shown in Fig. 19 as the fifteenth embodiment. This improves the workability in the manufacturing process and the manufacturing costs.

[0219] In the sixteenth embodiment, the inner peripheral ball protrusions 31s are formed intermittently in the circumferential direction, but the inner peripheral ball protrusions 31s can also be formed as circumferentially continuous protrusions on the inner peripheral surface 31n of the cover body 31. In this case, the felt sheet 16A is compressed as a pressing portion to inhibit the flow of the lubricant moving axially upward and outward from between the inner peripheral surface 31n of the cover body 31 and the outer peripheral surface 18r of the output outer flange portion 18. In this case, it is preferable that the shape of the top portion serving as the pressing portion is smooth also in the circumferential direction so that it does not get caught on the felt sheet 16A and tear the felt sheet 16A.

[0220] The sixteenth embodiment provides the same effects as the first embodiment described above.

[0221] [Seventeenth embodiment] Hereinafter, a seventeenth embodiment of the lubricant leakage prevention mechanism and gear mechanism according to the present invention will be described with reference to FIG. FIG. 21 is an enlarged cross-sectional view showing a positioner, which is a gear mechanism equipped with a lubricant leakage prevention mechanism 201 in this embodiment. This embodiment differs from the above-described second embodiment in terms of the pressing portion.

[0222] <Leak prevention mechanism> As shown in FIG. 21, the leakage suppression mechanism 201 includes an outer peripheral protrusion portion (pressing portion) 14s as a convex shape serving as a pressing portion. The outer peripheral protrusion 14s is formed on the outer peripheral surface 14d of the output block body 14. The outer peripheral protrusion 14s protrudes radially outward from the outer peripheral surface 14d. The outer peripheral protrusion 14s protrudes at a position facing the inner peripheral end 23t of the cover inner flange portion 23. The outer peripheral protrusion 14s is formed continuously around the entire circumference of the outer peripheral surface 14d. The outer peripheral protrusion 14s is formed on the outer peripheral surface 14d so as to be separated from the lower surface 18a in the axial direction. The outer peripheral protrusion 14s is separated from the lower surface 14a of the output block body 14 in the axial direction on the outer peripheral surface 14d. The outer peripheral protrusion 14s is separated from one surface 9a of the outer ring 9 in the axial direction on the outer peripheral surface 14d.

[0223] The inner peripheral portion 16b of the felt sheet 16 extends along the outer peripheral surface 14d of the output block body 14 to a position close to one surface 9a of the outer ring 9. That is, the inner peripheral portion 16b of the felt sheet 16 is bent toward the outer ring 9 by the outer peripheral surface 14d of the output block body 14, with the inner peripheral end portion 23t of the cover inner flange portion 23 as a fulcrum. At the same time, the inner peripheral portion 16b of the felt sheet 16 is pressed toward the inner peripheral end portion 23t of the cover inner flange portion 23 by the outer peripheral protrusion portion 14s of the outer peripheral surface 14d. That is, the outer peripheral protrusion portion 14s locally applies an axial thickness direction compressive force Pq1 shown in FIG. 13 to the curved felt sheet 16, strongly compressing the felt sheet 16.

[0224] The portion of the felt sheet 16 sandwiched between the outer peripheral protrusion 14s and the inner peripheral end 23t is pressed more strongly than the other portions. The portion of the felt sheet 16 sandwiched between the outer peripheral protrusion 14s and the inner peripheral end 23t is compressed more strongly by the axial thickness direction compressive force Pq1 than the other portions. This allows the felt sheet 16 to exhibit higher sealing properties that prevent the lubricant from leaking out from the inside to the outside in the radial direction compared to a case without a pressing portion.

[0225] The felt sheet 16 is not only axially sandwiched between the cover inner flange portion 23 and the output outer flange portion 18, but also axially sandwiched and supported between the outer peripheral protrusion portion 14s and the inner peripheral end portion 23t. This makes it possible to prevent the felt sheet 16 itself from rotating relative to the cover body 31 and the output block body 14 (output outer flange portion 18). The upper surface 16a of the felt sheet 16 is completely covered by the side wall 41a. This makes it possible to more reliably prevent leakage of lubricant used for meshing between the pinion 27 and the ring gear 4 immediately adjacent (directly above) the ring gear 4, and also makes it possible to prevent dust from entering the cover 15 from the outside.

[0226] The seventeenth embodiment provides the same effects as the first embodiment described above.

[0227] The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention. For example, the configuration of the first embodiment may be combined with the configuration of the second embodiment. For example, the inner peripheral portion of the felt sheet 16 of the first embodiment may be pressed by the outer peripheral surface 14d of the output block body 14 so as to be interposed in the gap between the cover inner flange portion 23 and the outer peripheral surface 14d of the output block body 14.

[0228] In the above embodiment, the leakage suppression mechanism 1 is applied to the positioner 100 used in construction machinery and industrial machinery. However, the present invention is not limited to this, and the leakage suppression mechanism 1 can be applied to various gear mechanisms instead of the positioner 100. For example, the leakage suppression mechanism 1 can be applied to a mechanism in which spur gears mesh with each other.

[0229] For example, the leakage suppression mechanism 1 can be applied even when the ring gear 4 has internal teeth instead of the external teeth 4a. In this case, the cover body 31 of the cover 15 can be formed so as to face the internal teeth in the radial direction and cover the internal teeth over the entire circumference. The shape of the output block body 14 is not limited to the above. In the above structure, it is sufficient that the output block body 14 has an outer peripheral surface 14d. When the cover body 31 is provided on the inner peripheral surface (internal teeth) of the ring gear 4, it is sufficient that the output block body 14 also has an inner peripheral surface. The gap between this inner peripheral surface and the cover body 31 can be sealed with a seal member.

[0230] In the above embodiment, the case where the felt sheet 16 is provided as a sealing member for sealing between the output block body 14 and the cover 15 has been described. However, this is not limited to this, and various sealing members can be used. For example, an oil seal, an O-ring, a rubber packing, etc. can be used instead of the felt sheet 16. These sealing members can also be used in combination. For example, the felt sheet 16 and the O-ring can be used in combination. In this case, the O-ring should be placed in a position where it is sandwiched between the cover inner flange portion 23 and the output outer flange portion 18 together with the felt sheet 16. This allows the O-ring to be slightly compressed, making it possible to use the O-ring effectively.

[0231] In the above embodiment, a case has been described in which the cover inner flange portion 23 is integrally formed with the cover 15, and the output outer flange portion 18 is integrally formed with the output block body 14. However, this is not limited to this, and at least one of the cover inner flange portion 23 or the output outer flange portion 18 may be formed. The felt sheet 16 does not have to be sandwiched in the axial direction. For example, the inner peripheral edge of the cover inner flange portion 23 may be raised in the axial direction, and the felt sheet 16 or other seal member may be sandwiched between this raised portion and the outer peripheral surface 14d of the output block body 14.

[0232] There is also no particular limitation on the method of forming the cover inner flange portion 23 and the output outer flange portion 18. For example, the case where the cover inner flange portion 23 is joined to the cover main body 31 by, for example, welding has been described. However, this is not limited to this, and the cover inner flange portion 23 may be formed by folding the cover main body 31 radially inward and then folding it back radially outward.

[0233] In the above embodiment, the output block body 14 is provided on one surface (one surface 9a of the outer ring 9) of the annular gear 4 serving as a gear. However, the present invention is not limited to this, and the output block body 14 (block body) may be provided on both surfaces of the gear. In this case, for example, the cover body 31 is configured to be separable in the thickness direction of the gear. With this configuration, the leakage suppression mechanism 1 (cover inner flange portion 23) can be easily provided on both surfaces of the gear.

[0234] In the above embodiment, the reduction gear unit 25 is an eccentric oscillating type reduction gear unit. However, the present invention is not limited to this, and various reduction gear units can be applied. For example, a planetary gear reduction gear unit can be applied instead of the eccentric oscillating type reduction gear unit.

[0235] Among the embodiments disclosed in this specification, those that are composed of multiple objects may be integrated, and conversely, those that are composed of one object may be divided into multiple objects. Regardless of whether they are integrated or not, it is sufficient that they are configured to achieve the object of the invention.

[0236] For example, the configurations of the above-mentioned embodiments may be appropriately selected and individually combined with the configurations of other embodiments. For example, in a configuration using an annular plate-shaped felt sheet 16 as a sealing member, it is possible to compress the felt sheet 16 and improve the sealing performance of the lubricant leaking outward from between the cover main body 31 and the output block body 14 by appropriately combining the configurations selected from the protrusion 18s, the ring groove 18m and the O-ring 18o, the ball protrusion 23s, the folded end 23st, the inclined surface 18as, the inclined flange portion 23A inside the cover, the outer circumferential groove 14m, the lower circumferential groove 18m, and the outer circumferential protrusion 14s.

[0237] Alternatively, in a configuration in which a cylindrical felt sheet 16A is used as a sealing member, in order to compress the felt sheet 16A by the axial width direction compressive force Pq4 and the radial thickness direction compressive force Pq3, configurations selected from the twelfth embodiment, the thirteenth embodiment, the fourteenth embodiment, the fifteenth embodiment, and the sixteenth embodiment can be appropriately combined. [Industrial Applicability]

[0238] According to the above-described lubricant leakage prevention mechanism and gear mechanism, leakage of the lubricant used for meshing of the gears in the immediate vicinity of the gears is prevented, thereby making it possible to prevent the device from becoming large. [Explanation of symbols]

[0239] 1,201,301...Lubricant leakage prevention mechanism, 4...Annular gear (gear), 4a...External teeth (tooth portion), 9...Outer ring, 9a one surface, 14...Output block body (block body), 14d...Outer peripheral surface (circumferential surface), 15...Cover, 16,16A...Felt sheet (sealing material, porous material), 18...Output outer flange portion (block body protruding portion), 18s...Protrusion portion (pressing portion), 18m...Ring groove (pressing portion), 18o...O-ring (pressing portion), 23s...Ball protrusion portion ( Pressing portion), 23st...folded end portion (pressing portion), 18as...inclined surface (pressing portion), 23A...cover inner inclined flange portion (pressing portion), 14m...outer peripheral groove (pressing portion), 18m...lower peripheral groove (pressing portion), 14s...outer peripheral protrusion portion (pressing portion), 18rs...outer peripheral protrusion portion (pressing portion), 31s...inner peripheral ball protrusion portion (pressing portion), 23...cover inner flange portion (cover protrusion portion), 31...cover main body (cover), 41...auxiliary cover, 100...positioner (gear mechanism)

Claims

1. a block body arranged adjacent to the teeth of the gear in a thickness direction of the gear and having a peripheral surface over the entire circumference; a cover provided around the entire circumference of the gear so as to face the toothed portion in a radial direction of the gear, the cover covering the toothed portion; a seal member disposed between the block body and the cover so as to overlap with the tooth portion in the axial direction and configured to suppress leakage of lubricant from between the block body and the cover; Equipped with The block body is provided on at least one of both surfaces of the gear in the thickness direction. Lubricant leakage prevention mechanism.

2. The cover is formed in a cylindrical shape, the cover has a cover protruding portion that protrudes radially inward from an inner circumferential surface of the cover and faces the tooth portion in the axial direction, The seal member is sandwiched between the cover protrusion and the block body in the axial direction. The lubricant leakage suppression mechanism according to claim 1 .

3. The sealing member includes a compressible porous material. The lubricant leakage suppression mechanism according to claim 2 .

4. The block body has a block body protruding portion protruding from the peripheral surface toward the cover, The seal member is sandwiched between the cover protruding portion and the block body protruding portion in the thickness direction. The lubricant leakage suppression mechanism according to claim 3 .

5. a block body arranged adjacent to the teeth of the gear in a thickness direction of the gear and having a peripheral surface over the entire circumference; a cover provided around the entire circumference of the gear so as to face the toothed portion in a radial direction of the gear, the cover covering the toothed portion; a seal member made of a compressible and deformable porous material that prevents leakage of lubricant from between the block body and the cover; Equipped with the block body is provided on at least one of both surfaces of the gear in the thickness direction, The cover is a cover protruding portion protruding from the cover toward the tooth portion; an auxiliary cover provided at a position spaced apart from the gear in the thickness direction relative to the cover protrusion; having The seal member is sandwiched between the cover protrusion and the auxiliary cover in the thickness direction. Lubricant leakage prevention mechanism.

6. The seal member is interposed in a gap between the cover protrusion and the peripheral surface of the block body. The lubricant leakage suppression mechanism according to claim 5.

7. The seal member is in surface contact with the block body and the cover. The mechanism for suppressing leakage of lubricant according to any one of claims 1 to 6.

8. a pressing portion provided on at least one of the block body and the cover for locally pressing the seal member against the block body or the cover; The mechanism for preventing leakage of lubricant according to claim 7.

9. The pressing portion is formed continuously or discontinuously in the circumferential direction of the gear. The mechanism for preventing leakage of lubricant according to claim 8.

10. The pressing portion presses the seal member in a radial direction of the gear or an axial direction of the gear. The lubricant leakage suppression mechanism according to claim 9.

11. The pressing portion is formed so as to be convex or concave in a direction in which the sealing member is pressed. The lubricant leakage suppression mechanism according to claim 10.

12. The pressing portion is formed so as to be convex in a direction in which the sealing member is pressed, and a top portion of the pressing portion is formed so as to be rounded. The mechanism for preventing leakage of lubricant according to claim 11.

13. The pressing portion is formed so as to narrow a distance between opposing surfaces of the block body and the cover. The lubricant leakage suppression mechanism according to claim 10.

14. a block body that is disposed adjacent to a tooth portion formed on an outer peripheral surface of the gear in a thickness direction of the gear and has an outer peripheral surface over the entire circumference of the gear; A cover that covers the tooth portion from a radially outer side; a seal member that suppresses leakage of a lubricant from between the block body and the cover; Equipped with The cover is a cover protruding portion protruding radially inward from the cover; an auxiliary cover provided at a position spaced apart from the gear in the thickness direction relative to the cover protrusion; having the block body has a block body protruding portion provided on at least one of both surfaces of the gear in the thickness direction and protruding radially outward from the outer circumferential surface of the block body, the seal member is sandwiched in the thickness direction by the cover protruding portion and the block body protruding portion, and is sandwiched in the thickness direction between the cover and the block body protruding portion by the cover protruding portion and the auxiliary cover, The seal member is interposed in a gap between the cover protrusion and the outer circumferential surface of the block body. Lubricant leakage prevention mechanism.

15. an annular gear formed integrally with an outer ring of the bearing and having teeth on an outer periphery thereof; a block body disposed adjacent to the tooth portion in a thickness direction and having an outer circumferential surface along the entire circumference of the annular gear; A cylindrical cover that covers the tooth portion from a radially outer side; a seal member made of a compressible and deformable porous material that prevents leakage of lubricant from between the block body and the cover; Equipped with the cover has a cover protruding portion that protrudes radially inward from an inner circumferential surface of the cover and faces the tooth portion in the axial direction, the block body has a block body protruding portion that is provided on one surface of the ring gear in the thickness direction and protrudes radially outward from the outer circumferential surface of the block body, the seal member is sandwiched between the cover protruding portion and the block body protruding portion in the thickness direction. Gear mechanism.

16. an annular gear formed integrally with an outer ring of the bearing and having teeth on an outer periphery thereof; a block body arranged adjacent to the tooth portion in a thickness direction and having an outer circumferential surface over the entire circumference; A cover that covers the tooth portion from a radially outer side; a seal member that suppresses leakage of a lubricant from between the block body and the cover; Equipped with The cover is a cover protruding portion protruding radially inward from the cover; an auxiliary cover provided at a position spaced apart from the ring gear in the thickness direction relative to the cover protrusion; having the block body has a block body protruding portion that is provided on one surface of the ring gear in the thickness direction and protrudes radially outward from the outer circumferential surface of the block body, the seal member is sandwiched in the thickness direction by the cover protruding portion and the block body protruding portion, and is sandwiched in the thickness direction between the cover and the block body protruding portion by the cover protruding portion and the auxiliary cover, The seal member is interposed in a gap between the cover protrusion and the outer circumferential surface of the block body. Gear mechanism.

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