Harmonic speed reducer for preventing oil leakage

Abstract

To provide a harmonic speed reducer preventing oil leakage.SOLUTION: A harmonic speed reducer for preventing oil leakage includes a wave generator, a flexible gear, a rigid gear, and a bearing. A labyrinth-type flow passage is formed between an inner ring body and an outer ring body of the bearing, and the labyrinth-type flow passage communicates with an engagement point of the flexible gear and the rigid gear. The labyrinth-type flow passage has a first flow passage portion which is continuously connected to a rolling groove, a second flow passage portion which is continuously connected to the first flow passage portion, and curved while having an angle between the first flow passage portion and itself, and a third flow passage portion which is continuously connected to the second flow passage portion, and curved while having an engine between the second flow passage portion and itself. The third flow passage portion exerts a curved shape. By this constitution, a situation that a lubricant in the engagement point of the flexible gear and the rigid gear is mutually mixed with oil resulting from a flow-out of the lubricant which exists between the inner ring body and the outer ring body.SELECTED DRAWING: Figure 3A

Description

[Technical field]

[0001] The present invention relates to a harmonic speed reducer, and more particularly to a harmonic speed reducer that prevents oil outflow. [Background technology]

[0002] A harmonic reducer is a reduction structure in which a wave generator generates a controllable elastic deformation in a flexible gear, which then meshes with a rigid gear to transmit force.

[0003] Among conventional patent documents, for example, Patent Document 1 discloses a top hat harmonic gear device. This device primarily prevents or reduces the situation where excessive lubricant enters the bearing by sealing between the gear side gap and the second bearing side gap with a bearing seal. In addition, any excess lubricant that has flowed into the bearing is returned to the gap on the gear side by the bearing seal. Thus, the oil seal prevents or suppresses excess lubricant that has flowed into the bearing from leaking out. However, the bearing seal could only restrict the flow of oil in one direction, and could only prevent the oil on the gear side from flowing into the bearing section, but could not prevent the oil in the bearing section from flowing into the gear side. This resulted in oil mixing and oil leakage from the bearings, resulting in insufficient lubrication of the bearings.

[0004] Also, for example, Patent Document 2 discloses a flexible meshing gear system. This system required structural modifications to many components to prevent the oil on the gear side from entering the bearing area. For example, it is necessary to process the second internal gear member integrally with the main bearing and simultaneously control the accuracy of the bearing raceway and the gear accuracy, which increases the difficulty of manufacturing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Taiwan Patent Application Publication No. 107104961 [Patent Document 2] Japanese Patent Application Publication No. 2018-012540 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the present inventors believed that the above-mentioned drawbacks could be improved, and as a result of extensive research, they came to propose the present invention, which effectively improves the above-mentioned problems through rational design.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a harmonic reducer that prevents the occurrence of oil mixing and oil outflow.

[0008] Another object of the present invention is to provide a harmonic reducer that prevents oil spillage, which reduces the manufacturing cost. [Means for solving the problem]

[0009] The main invention for achieving the above object is a bearing including a wave generator, a flexible gear provided on the wave generator and having an external gear portion, a rigid gear rotatably meshed with the flexible gear and having an internal gear portion meshed with the external gear portion, and an inner race body, an outer race body, and a plurality of rolling members disposed between the flexible gear and the rigid gear, the inner race body having an inner rolling groove, the outer race body having an outer rolling groove which forms a rolling groove together with the inner rolling groove, and the outer race body and a maze-type flow passage is formed between the inner ring and the rolling groove, the maze-type flow passage having a first flow passage portion connected to the rolling groove, a second flow passage portion connected to the first flow passage portion and curved at an angle to the first flow passage portion, and a third flow passage portion connected to the second flow passage portion and curved at an angle to the second flow passage portion, the third flow passage portion being curved, and a plurality of the rolling members are provided with bearings installed in the rolling groove.

[0010] Preferably, the inner race of the bearing is fixed to the rigid gear, and the outer race of the bearing is fixed to the flexible gear. Alternatively, the inner race of the bearing is fixed to the flexible gear, and the outer race of the bearing is fixed to the rigid gear.

[0011] Preferably, the inner race of the bearing further has a first inner portion located on one side of the inner rolling groove and a second inner portion located on the other side of the inner rolling groove. The outer race of the bearing further has a first outer portion located on one side of the outer rolling groove and forming an outer flow passage together with the first inner portion, and a second outer portion located on the other side of the outer rolling groove and forming the labyrinth-type flow passage together with the second inner portion.

[0012] Preferably, a flow path recess is recessed into the second inner part of the inner race, and the second outer part of the outer race has a flow path protrusion extending to a position between the second inner part and the flexible gear and positioned within the flow path recess. The third flow path portion is formed by providing a gap between the flow path protrusion and the flow path recess.

[0013] Preferably, the flexible gear has a first ring portion, the first ring portion having a ring body parallel to the axis and for providing each of the external gear portions, an extension portion connected to the ring body and perpendicular to the axis, and a flange portion connected to the extension portion. The second outer portion of the outer ring body has an inclined surface extending to a position between the second inner portion and the extension portion and facing the extension portion, and the included angle between the inclined surface and the extension portion is 5 to 10 degrees.

[0014] Preferably, the second outer portion is integrally formed or removably mounted to the outer race.

[0015] Preferably, the upper surface of the convex portion of the flow passage of the outer race is flat, concave arc-shaped, sawtooth-shaped, or protruding arc-shaped toward the concave portion of the flow passage of the inner race.

[0016] Preferably, the concave portion of the flow passage of the inner race has an upper surface facing the convex portion of the flow passage of the outer race, the upper surface being flat or sawtooth-shaped.

[0017] Preferably, the present invention further comprises an oil reservoir device, the oil reservoir device being made of a porous material and being installed in a recess of the flow path or a protrusion of the flow path.

[0018] Preferably, the oil storage equipment has a first oil storage section installed in a recess of the flow path, and a second oil storage section connected to the first oil storage section and positioned within the second flow path section.

[0019] Preferably, a flow path recess is formed in the second outer portion of the outer race, and the second inner portion of the inner race has a flow path protrusion extending to a position between the second outer portion and the flexible gear and positioned within the flow path recess. The third flow path portion is formed by providing a gap between the convex portion of the flow path and the concave portion of the flow path.

[0020] Preferably, the second inner portion is integrally formed or removably mounted to the inner race.

[0021] Preferably, the upper surface of the convex portion of the flow passage of the inner race is flat, concave, arcuate, sawtooth, or protruding toward the concave portion of the flow passage of the outer race.

[0022] Preferably, the concave portion of the flow passage of the outer race has a flat or sawtooth upper surface facing the convex portion of the flow passage of the inner race.

[0023] Preferably, the oil storage device further comprises an oil storage device made of a porous material and installed in the recess of the flow path or the protrusion of the flow path. Effect of the Invention

[0024] As described above, the present invention has the following advantages. A labyrinth-type flow passage is formed between the inner race and the outer race of the bearing, and the labyrinth-type flow passage is connected to the meshing portion between the flexible gear and the rigid gear. This prevents the lubricating oil between the inner and outer races from leaking out and mixing with the lubricating oil at the meshing points between the flexible gear and rigid gear. Furthermore, the present invention achieves the effect of preventing oil leakage simply by modifying the structures of the inner and outer races of the bearing. Therefore, there are fewer design variations and fewer materials required for manufacturing, and manufacturing costs can be effectively reduced.

[0025] Other features of the present invention will become apparent from the following detailed description of the present invention and the accompanying drawings. [Brief description of the drawings]

[0026] [Figure 1] 1 is a schematic configuration diagram showing a harmonic reducer for preventing oil outflow according to a first embodiment of the present invention. FIG. [Diagram 2] FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. [Figure 3A] 1 is a partially enlarged view showing a harmonic reducer for preventing oil outflow according to a first embodiment of the present invention. FIG. [Figure 3B] FIG. 3B is a partially enlarged view of FIG. 3A. [Figure 4] FIG. 5 is a partially enlarged view showing a harmonic reducer for preventing oil outflow according to a second embodiment of the present invention. [Diagram 5] FIG. 11 is a partially enlarged view showing a harmonic reducer for preventing oil outflow according to a third embodiment of the present invention. [Figure 6] FIG. 11 is a partially enlarged view showing a harmonic reducer for preventing oil outflow according to a fourth embodiment of the present invention. [Figure 7] FIG. 11 is a partially enlarged view showing a harmonic reducer for preventing oil outflow according to a fifth embodiment of the present invention. [Figure 8] FIG. 13 is a partially enlarged view showing a harmonic reducer for preventing oil outflow according to a sixth embodiment of the present invention. [Figure 9] FIG. 13 is a partially enlarged view showing a harmonic reducer for preventing oil outflow according to a seventh embodiment of the present invention. [Figure 10] FIG. 13 is a partially enlarged view showing a harmonic reducer for preventing oil outflow according to an eighth embodiment of the present invention. [Figure 11A] FIG. 13 is a partially enlarged view showing a harmonic reducer for preventing oil outflow according to a ninth embodiment of the present invention. [Figure 11B] FIG. 19 is a partially enlarged view showing a harmonic reducer for preventing oil leakage according to a tenth embodiment of the present invention. [Figure 12] FIG. 19 is a partial enlarged view showing a harmonic reducer for preventing oil leakage according to an eleventh embodiment of the present invention. [Figure 13]FIG. 12 is a partial enlarged view showing a harmonic reducer for preventing oil leakage according to a twelfth embodiment of the present invention. [Figure 14A] FIG. 11 is a partially enlarged view showing a harmonic reducer for preventing oil leakage according to another embodiment of the first embodiment of the present invention, illustrating the state in which the second outer portion is fastened to the outer ring body with a screw. [Figure 14B] FIG. 11 is a partially enlarged view showing a harmonic reducer for preventing oil leakage according to another embodiment of the first embodiment of the present invention, illustrating the state in which a screw penetrates the flexible gear and the second outer part is fastened to the outer ring body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It goes without saying that the present invention is not limited to the following examples, and can be modified as desired without departing from the gist of the present invention.

[0028] <First Example> The configuration of a harmonic reducer for preventing oil leakage according to a first embodiment of the present invention is shown in FIGS. 1 to 3B. The harmonic reducer is mainly composed of a wave generator 10, a flexible gear 20, a rigid gear 30, and a bearing A. Each of these will be described below.

[0029] The wave generator 10 comprises an elliptical shaft 11 rotating about an axis L, and a flexible bearing 12 mounted on and engaged by the elliptical shaft 11 . In this embodiment, the flexible bearing 12 has a flexible inner ring 121 fitted onto the elliptical shaft 11, a flexible outer ring 122 corresponding to the flexible inner ring 121, and a plurality of rolling members 123 installed between the flexible inner ring 121 and the flexible outer ring 122.

[0030] The flexible gear 20 has a first ring portion 21 that is covered by the flexible bearing 12 and partially attached to the flexible outer ring 122, and a plurality of external gear portions 22 that are spaced apart on the outside of the first ring portion 21 so as to surround the axis L. The elliptical shaft 11 of the wave generator 10 is driven by a driving source (eg, a motor) to rotate the flexible bearing 12 and the flexible gear 20 in unison. In this embodiment, the flexible gear 20 is hollow, and the first ring portion 21 has a ring body 211 that is parallel to the axis L and for installing each of the external gear portions 22, an extension portion 212 that is connected to the ring body 21 and perpendicular to the axis L, and a flange portion 213 that is connected to the extension portion 212.

[0031] The rigid gear 30 is attached to the flexible gear 20 and has a second ring portion 31 and a plurality of internal gear portions 32 spaced apart inside the second ring portion 31 so as to surround the axis L, and each of the internal gear portions 32 and each of the external gear portions 22 are partially meshed with each other.

[0032] The bearing A is disposed between the flexible gear 20 and the rigid gear 30, and includes an inner race 40, an outer race 50, and a plurality of rolling members 60.

[0033] The inner ring body 40 is fixed to the second ring portion 31 of the rigid gear 30, and has an inner rolling groove 41, a first inner portion 42 located on one side of the inner rolling groove 41, and a second inner portion 43 located on the other side of the inner rolling groove 41.

[0034] The outer race 50 is fixed to the flange portion 213 of the flexible gear 20, and has an outer rolling groove 51 which forms a rolling groove 91 together with the inner rolling groove 41, a first outer portion 52 which is located on one side of the outer rolling groove 51 and forms an outer flow path 92 together with the first inner portion 42, and a second outer portion 53 which is located on the other side of the outer rolling groove 51 and forms a maze-type flow path 93 together with the second inner portion 43. In this embodiment, the second outer portion 53 is integrally formed with the outer race 50 . However, the present invention is not limited to this, and the second outer portion 53 is removably installed on the outer race body 50. The removal method is to fasten the second outer part 53 to the outer ring body 50 using a screw 54, as shown in FIG. 14A, or to fasten the second outer part 53 to the outer ring body 50 by clamping it between the flexible gear 20 and the outer ring body 50, and then to fasten the second outer part 53 to the outer ring body 50 after a screw 54 is inserted into the flexible gear 20, as shown in FIG. 14B. In addition, the second outer part 53 is fixed to the outer race 50 by engagement, adhesion or other methods. The outer flow passage 92 is connected to the rolling groove 91, and an oil stop ring seal 99 is installed at the outlet of the outer flow passage 92, the maze-type flow passage 93 is connected to the rolling groove 91, and the maze-type flow passage 93 is connected to the meshing point between the flexible gear 20 and the rigid gear 30.

[0035] In this embodiment, the maze-shaped flow path 93 has a first flow path portion 931 connected to the rolling groove 91, a second flow path portion 932 connected to the first flow path portion 931 and curved at an angle to the first flow path portion 931, and a third flow path portion 933 connected to the second flow path portion 932 and curved at an angle to the second flow path portion 932. The third flow path portion 933 has a plurality of curved shapes, and the first flow path portion 931, the second flow path portion 932, and the third flow path portion 933, which are curved relative to one another, cause the labyrinth-type flow path 93 to have a labyrinth-like structure with a plurality of curved shapes. The second inner portion 43 of the inner ring 40 is farther from the expansion portion 212 of the flexible gear 20 than the second outer portion 53 of the outer ring 50, and a flow path recess 431 is recessed in the second inner portion 43 of the inner ring 40 so as to face the expansion portion 212 of the flexible gear 20, and the second outer portion 53 of the outer ring 50 extends to a position between the second inner portion 43 and the expansion portion 212 and has a flow path protrusion 531 positioned within the flow path recess 431. By providing a gap between the convex portion 531 of the flow path and the concave portion 431 of the flow path, multiple curved third flow path portions 933 are formed, and the upper surface of the convex portion 531 of the flow path of the outer race 50 is designed to be flat.

[0036] The plurality of rolling members 60 are installed in a rolling groove 91 formed between the inner race 40 and the outer race 50 .

[0037] The above is a description of the configuration of each of the main components according to the first embodiment of the present invention. The effects of the present invention will be described below.

[0038] 1. Prevent oil mixing An outer flow passage 92 and a labyrinth-type flow passage 93 are formed between the inner race 40 and the outer race 50 of the bearing A, and the labyrinth-type flow passage 93 is connected to the meshing point between the flexible gear 20 and the rigid gear 30. The present invention particularly adopts a maze-type structure design for the maze-type flow path 93, and the maze-type flow path 93 has a flow path structure with multiple curved shapes due to a first flow path portion 931, a second flow path portion 932, and a third flow path portion 933 that are curved relative to each other. In particular, in the third flow path portion 933, a blocking gap and an expansion cavity are formed between the flow path recess 431 and the flow path protrusion 531 due to the structural design of the two, and when the lubricating oil sealed within the bearing A passes through the curved labyrinth gap, a throttling effect is generated, thereby achieving the purpose of preventing leakage. By doing this, the present invention prevents a situation in which lubricating oil leaks out between the inner race 40 and the outer race 50 and mixes with the lubricating oil at the meshing points between the flexible gear 20 and the rigid gear 30.

[0039] 2. Reduce manufacturing costs The present invention achieves the effect of preventing oil leakage simply by modifying the structures of the inner race 40 and the outer race 50 of the bearing A. In this way, the design variations and the number of parts required for manufacturing are reduced, and manufacturing costs can be effectively reduced.

[0040] Incidentally, the second outer portion 53 of the outer race 50 extends to a position between the second inner portion 43 of the inner race 40 and the extension portion 212 of the flexible gear 20, and has an inclined surface 533 directed toward the extension portion 212, and the included angle B between the inclined surface 533 and the extension portion 212 is 5 to 10 degrees. By doing this, when the flexible gear 20 is linked and deformed, the position of the second outer portion 53 of the outer ring body 50 is affected, preventing interference between the second outer portion 53 of the outer ring body 50 and the second inner portion 43 of the inner ring body 40 and affecting the smooth operation of the outer ring body 50 and the inner ring body 40.

[0041] <Second Example> FIG. 4 shows the configuration of a harmonic reducer for preventing oil outflow according to a second embodiment of the present invention. The differences between this embodiment and the first embodiment are that the upper surface of the convex portion 531A of the flow passage of the second outer portion 53A of the outer race 50A is sawtooth-shaped toward the concave portion 431 of the flow passage of the inner race 40, and the third flow passage portion 933 of the maze-shaped flow passage 93 is more curved, forming a blocking gap and an expansion cavity, and the structural design of the maze-shaped flow passage 93 further prevents the leakage of lubricating oil between the inner race 40 and the outer race 50A.

[0042] <Third Example> FIG. 5 shows the configuration of a harmonic reducer for preventing oil outflow according to a third embodiment of the present invention. The present embodiment differs from the first embodiment in that the recess 431A of the flow passage of the second inside portion 43A of the inner race 40A is shaped like sawtooth toward the projection 531 of the flow passage of the outer race 50. However, the present invention is not limited to this, and the recess of the flow passage of the inner race 40A may have a recessed arc shape or a protruding arc shape. By doing so, the third flow passage portion 933 of the maze-type flow passage 93 is curved more, and presents a blocking gap and an expansion cavity state, and the structural design of the maze-type flow passage 93 further prevents the leakage of lubricating oil between the inner race 40A and the outer race 50.

[0043] <Fourth Example> FIG. 6 shows the configuration of a harmonic reducer for preventing oil outflow according to a first embodiment of the present invention. The present embodiment differs from the first embodiment in that the upper surface of the convex portion 531B of the flow passage of the second outer portion 53B of the outer race 50B is arcuately recessed toward the concave portion 431 of the flow passage of the inner race 40. By doing so, the third flow passage portion 933 of the maze-type flow passage 93 is curved more, forming a blocking gap and an expansion cavity, and the structural design of the maze-type flow passage 93 further prevents the leakage of lubricating oil between the inner race 40 and the outer race 50B.

[0044] <Fifth Example> FIG. 7 shows the configuration of a harmonic reducer for preventing oil outflow according to a fifth embodiment of the present invention. The present embodiment differs from the first embodiment in that the upper surface of the convex portion 531C of the flow passage of the second outer portion 53C of the outer race 50C presents an arc shape that protrudes toward the concave portion 431 of the flow passage of the inner race 40. By doing so, the third flow passage portion 933 of the maze-type flow passage 93 is curved more, and presents a blocking gap and an expansion cavity state, and the structural design of the maze-type flow passage 93 further prevents the leakage of lubricating oil between the inner race 40 and the outer race 50C.

[0045] <Sixth Example> FIG. 8 shows the configuration of a harmonic reducer for preventing oil outflow according to a sixth embodiment of the present invention. The difference between this embodiment and the first embodiment is that the harmonic reducer for preventing oil leakage further has an oil storage device 94, which is made of a porous material and is installed in the recess 431 of the flow path of the inner race 40, and there is a gap of 0.2 mm to 1.5 mm between the oil storage device 94 and the protrusion 531 of the flow path of the outer race 50. Additionally, the oil storage facility 94 is made of felt. However, the present invention is not limited to this, and sponge, composite materials, etc. may also be used. By installing the oil storage equipment 94, the third flow path portion 933 of the maze-type flow path 93 further has an oil storage effect, further preventing leakage of lubricating oil between the inner race 40 and the outer race 50.

[0046] <Seventh Example> FIG. 9 shows the configuration of a harmonic reducer for preventing oil outflow according to a seventh embodiment of the present invention. The present embodiment differs from the first embodiment in that the harmonic reducer for preventing oil outflow further includes an oil storage facility 95 . The oil storage equipment 95 is made of a porous material and is installed in the maze-shaped flow path 93. It has a first oil storage section 951 that is installed in the recess 431 of the flow path of the inner race 40 and is located in the third flow path portion 933, and a second oil storage section 952 that is connected to the first oil storage section 951 and is located in the second flow path portion 932. There is a gap between the oil storage facility 95 and the second outer portion 53 of the outer race 50 and between the oil storage facility 95 and the convex portion 531 of the flow passage. The oil storage facility 95 is made of felt. However, the present invention is not limited to this, and sponge, composite materials, etc. may also be used. By installing the oil storage equipment 95, the second flow path portion 932 and the third flow path portion 933 of the maze-type flow path 93 further have an oil storage effect, further preventing the leakage of lubricating oil between the inner race 40 and the outer race 50.

[0047] <Eighth Example> FIG. 10 shows the configuration of a harmonic reducer for preventing oil outflow according to an eighth embodiment of the present invention. The present embodiment differs from the first embodiment in that the harmonic reducer for preventing oil outflow further includes an oil storage facility 96. The oil storage device 96 is made of a porous material and is installed in the convex portion 531 of the flow path of the outer race 50, and there is a gap of 0.2 mm to 1.5 mm between the oil storage device 96 and the concave portion 431 of the flow path of the inner race 40. Additionally, the oil storage facility 96 is made of felt. However, the present invention is not limited to this, and sponge, composite materials, etc. may also be used. By installing the oil storage equipment 96, the third flow path portion 933 of the maze-type flow path 93 further has an oil storage effect, further preventing leakage of lubricating oil between the inner race 40 and the outer race 50.

[0048] <Ninth Example> FIG. 11A shows the configuration of a harmonic reducer for preventing oil leakage according to a ninth embodiment of the present invention. The present embodiment differs from the first embodiment in that a recess 532 for a flow passage is recessed in the second outer portion 53 of the outer race 50 . The second inner portion 43 of the inner race 40 extends to a position between the second outer portion 53 and the flange portion 213 of the flexible gear 20, and has a flow path protrusion 432 positioned within the flow path recess 532. A curved third flow path portion 933 is formed by providing a gap between the convex portion 432 of the flow path and the concave portion 532 of the flow path, and the labyrinth flow path 93 has a labyrinth structure with a plurality of curved shapes. This prevents the lubricating oil from leaking out between the inner race 40 and the outer race 50 and mixing with the lubricating oil at the meshing portion between the flexible gear and the rigid gear. In this embodiment, the second inside portion 43 is integrally formed with the inner race 40 . However, the present invention is not limited thereto, and the second inner portion 43 may be removably attached to the inner race 40 by screwing, engaging, gluing, or other methods. Other structural changes and effects are the same as those of the second to fifth embodiments described above, so the description thereof will not be repeated here.

[0049] <Tenth Example> FIG. 11B shows the configuration of a harmonic reducer for preventing oil leakage according to a tenth embodiment of the present invention. The present embodiment is different from the ninth embodiment in that the harmonic reducer for preventing oil outflow further includes an oil storage facility 97 . The oil storage device 97 is made of a porous material and is installed in the recess 532 of the flow path, with a gap of 0.2 mm to 1.5 mm between the oil storage device 97 and the protrusion 432 of the flow path of the inner race 40. By installing the oil storage equipment 97, the third flow path portion 933 of the maze-type flow path 93 further has an oil storage effect, further preventing leakage of lubricating oil between the inner race 40 and the outer race 50. Other structural changes and effects are the same as those of the sixth to eighth embodiments described above, so the description thereof will not be repeated here.

[0050] <Eleventh Example> FIG. 12 shows the configuration of a harmonic reducer for preventing oil outflow according to an eleventh embodiment of the present invention. The present embodiment differs from the first embodiment in that the inner race 40 is provided with a recess 431 for the flow passage. The outer race 50 is provided with a flow passage protrusion 531 positioned within the flow passage recess 431, so that the bearing A is installed between the flexible gear 20A and the rigid gear 30A, which are cup-shaped. In particular, the inner race 40 is fixed to the flange portion 213A of the flexible gear 20A, and the outer race 50 is fixed to the second ring portion 31A of the rigid gear 30A, thereby achieving another embodiment.

[0051] <Twelfth Example> FIG. 13 shows the configuration of a harmonic reducer for preventing oil outflow according to a twelfth embodiment of the present invention. The present embodiment differs from the ninth embodiment in that the outer race 50 is provided with a recess 532 for the flow passage. The inner race 40 is provided with a flow passage protrusion 432 positioned within the flow passage recess 532, so that the bearing A is installed between the flexible gear 20A and the rigid gear 30A, which are cup-shaped. In particular, the inner race 40 is fixed to the flange portion 213A of the flexible gear 20A, and the outer race 50 is fixed to the second ring portion 31A of the rigid gear 30A, thereby achieving another embodiment.

[0052] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various modifications and improvements can be made to the above embodiments. It will be apparent from the description of the claims that such modified or improved forms may also be included within the technical scope of the present invention. [Explanation of symbols]

[0053] 10 Wave Generator L axis 11 Oval shaft 12 Flexible bearing 121 Flexible inner ring 122 Flexible outer ring 123 Rolling parts 20 Flexible Gear 20A Flexible Gear 21 First Ring Section 211 Ring body 212 Extension 213 Flange part 213A Flange 22 External gear section 30 Rigid Gear 30A Rigid Gear 31 Second Ring Section 31A Second Ring Section 32 Internal gear section A Bearing B angle 40 Inner race 40A inner ring 41 Inner rolling groove 42 1st inner part 43 Second inner part 43A Second inner part 431 Concave part of flow channel 432 Convex part of flow channel 50 Outer wheel 50A Outer wheel 50B Outer wheel 50C outer wheel 51 Outer rolling groove 52 First outer part 53 Second outer part 53A Second outer part 53B 2nd outer part 53C 2nd outer part 531 Convex part of flow channel 531A Convex part of flow path 531B Convex part of flow path 531C Convex part of flow path 532 Recess of flow channel 533 Slope 54 Screw 60 Rolling members 91 Rolling groove 92 Outer channel 93 Maze-shaped channel 931 First flow path section 932 Second flow path part 933 Third flow path section 94 Oil storage facility 95 Oil storage facility 96 Oil storage facility 97 Oil storage facility 951 No. 1 Oil Reservoir 952 No. 2 Oil Reservoir 99 Oil stop ring seal

Claims

1. A wave generator; a flexible gear disposed on the wave generator and having an external gear portion; a rigid gear rotatably meshed with the flexible gear and having an internal gear portion meshed with the external gear portion; a bearing installed between the flexible gear and the rigid gear and including an inner race, an outer race, and a plurality of rolling members, wherein the inner race has an inner rolling groove, the outer race has an outer rolling groove which forms a rolling groove together with the inner rolling groove, a labyrinth-shaped flow path is formed between the outer race and the inner race, the labyrinth-shaped flow path has a first flow path portion connected to the rolling groove, a second flow path portion connected to the first flow path portion and curved at an angle to the first flow path portion, and a third flow path portion connected to the second flow path portion and curved at an angle to the second flow path portion, the third flow path portion having a curved shape, and a plurality of the rolling members are installed in the rolling groove.

2. 2. The harmonic reducer for preventing oil leakage as claimed in claim 1, characterized in that the inner race of the bearing further has a first inner portion located on one side of the inner rolling groove and a second inner portion located on the other side of the inner rolling groove, and the outer race of the bearing further has a first outer portion located on one side of the outer rolling groove and forming an outer flow path together with the first inner portion, and a second outer portion located on the other side of the outer rolling groove and forming the maze-type flow path together with the second inner portion.

3. A harmonic reducer for preventing oil leakage as described in claim 2, characterized in that a flow path recess is formed in the second inner portion of the inner ring, the second outer portion of the outer ring extends to a position between the second inner portion and the flexible gear and has a flow path convex portion located within the flow path recess, and the third flow path portion is formed by having a gap between the flow path convex portion and the flow path recess.

4. The flexible gear has a first ring portion, the first ring portion having a ring body parallel to an axis and for providing each of the external gear portions, an extension portion connected to the ring body and perpendicular to the axis, and a flange portion connected to the extension portion, the second outer portion of the outer ring body extends to a position between the second inner portion and the extension portion and has an inclined surface facing the extension portion, and the included angle between the inclined surface and the extension portion is 5 to 10 degrees.

5. 4. The harmonic reducer for preventing oil outflow according to claim 3, further comprising an oil storage device made of a porous material and installed in a recess of the flow path or in a protrusion of the flow path.

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