Flexible mesh gear device

Abstract

To suppress wear between an external gear and an outer ring of an exciter bearing.SOLUTION: A flexible engagement type gear device 1 comprises an exciter 10A, an external gear 11 that is flexibly deformed by the exciter, and an exciter bearing 12 arranged between the exciter and the external gear. The exciter bearing has an outer ring 123 fitted to the inner periphery of the external gear. At least one of the inner peripheral surface of the external gear and the outer peripheral surface of the outer ring is made of oil-impregnated materials 111, 124. When the exciter 10A rotates, a rolling element 122 of the exciter bearing 12 presses the outer ring 123 and the external gear 11 radially outward, where these interfaces therebetween are lubricated by the oil-impregnated materials 111, 124.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] A flexible mesh gear device including an external gear that undergoes flexural deformation is known (see, for example, Patent Document 1). The external gear undergoes flexural deformation when a vibration exciter fitted inside the external gear rotates via a vibration exciter bearing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5337008 Summary of the Invention [Problem to be solved by the invention]

[0004] Between the external gear, which is subject to flexural deformation, and the outer ring of the vibration exciter bearing, strong contact occurs on the long shaft side, causing the lubricant at the interface to leak out, which can result in wear such as fretting.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to suppress wear between an external gear and an outer ring of a vibration exciter bearing. [Means for solving the problem]

[0006] The present invention provides a flexible mesh gear device including a vibration exciter, an external gear that is flexibly deformed by the vibration exciter, and a vibration exciter bearing disposed between the vibration exciter and the external gear, the vibration exciter bearing has an outer ring that fits onto an inner periphery of the external gear, At least one of the inner peripheral surface of the external gear and the outer peripheral surface of the outer ring is made of an oil-retaining material. Based on the above. Furthermore, the first aspect of the present invention, in addition to the basic configuration, the outer peripheral surface of the outer ring is made of an oil-retaining material, a high-rigidity layer made of a material having a larger Young's modulus than the oil-impregnating material is provided radially inward of the layer of the oil-impregnating material, and a rolling surface is formed on the inner periphery of the high-rigidity layer; The oil-retaining material layer is formed in a plurality of layers aligned along the axial direction, A gap region is formed between the layers of the oil-retaining material in the axial direction. Furthermore, the second aspect of the present invention, in addition to the basic configuration, The oil-retaining material is a sintered metal. Furthermore, the third aspect of the present invention is that, in addition to the basic configuration, Inner surface of external gear is made of oil-containing material. 、 A high-rigidity layer is provided radially outward of the layer of oil-retaining material and is made of a material having a Young's modulus greater than that of the oil-retaining material, and external teeth are formed on the high-rigidity layer. The layer of the oil-retaining material of the external gear is configured so that its axial width is narrower than that of the outer ring. Furthermore, the fourth aspect of the present invention is that, in addition to the basic configuration, Outer ring circumference is made of oil-containing material. 、 a high-rigidity layer made of a material having a larger Young's modulus than the oil-impregnating material is provided radially inward of the layer of the oil-impregnating material, and a rolling surface is formed on the inner periphery of the high-rigidity layer; The bearing has a plurality of rolling elements arranged in an axial direction and a plurality of the outer rings arranged in an axial direction, The layers of the oil-retaining material of the outer rings are configured to have a width in the axial direction wider than that of the rolling elements held radially inward. Effect of the Invention

[0007] According to the present invention, wear between the external gear and the outer ring of the vibration exciter bearing can be suppressed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a flexible mesh gear device according to an embodiment. [Diagram 2] 4 is a cross-sectional view perpendicular to the axis of an outer ring of a vibration exciter bearing having an external gear and an oil-retaining material layer. FIG. [Diagram 3] 3 is an enlarged cross-sectional view taken along the axial direction of the external gear and the outer ring of the vibration exciter bearing of FIG. 2. [Figure 4] 4(A) to 4(C) are enlarged cross-sectional views of region E in FIG. [Diagram 5] 1 is a cross-sectional view perpendicular to the axis of an external gear having an oil-retaining material layer and an outer ring of a vibration exciter bearing. FIG. [Figure 6] 6(A) to 6(C) are enlarged cross-sectional views taken along the axial direction of the external gear and the outer ring of the vibration exciter bearing of FIG. [Figure 7]7(A) to 7(C) are enlarged cross-sectional views of region F in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0010] [Configuration of a flexible mesh gear device] Fig. 1 is an axial cross-sectional view showing a flexible mesh gear device 1 according to the present invention. The upper half of the flexible mesh gear device 1 shown in Fig. 1 is an axial cross-sectional view including the minor axis of a vibration exciter 10A (described later), and the lower half of the flexible mesh gear device 1 is an axial cross-sectional view including the major axis of the vibration exciter 10A. As shown in this figure, the flexible mesh gear device 1 is a cylindrical flexible mesh gear device and comprises a vibration exciter shaft 10, an external gear 11, a first internal gear 31G and a second internal gear 32G, two vibration exciter bearings 12, a casing 33, a first cover 34, and a second cover 35.

[0011] The vibrator shaft 10 is a hollow cylindrical shaft that rotates around a rotation axis O1, and has a vibrator 10A whose cross section perpendicular to the rotation axis O1 has a non-circular (e.g., elliptical) outer shape, and shaft portions 10B and 10C provided on both sides of the vibrator 10A in the axial direction. The elliptical shape is not limited to a geometrically strict ellipse, but includes an approximate ellipse. The shaft portions 10B and 10C are shafts whose cross section perpendicular to the rotation axis O1 has a circular outer shape. In the following description, the direction along the rotation axis O1 is referred to as the "axial direction", the direction perpendicular to the rotation axis O1 is referred to as the "radial direction", and the direction of rotation about the rotation axis O1 is referred to as the "circumferential direction". In addition, in the axial direction, the side that is connected to an external driven member (left side in the figure) is referred to as the "output side", and the side opposite the output side (right side in the figure) is referred to as the "anti-output side".

[0012] The external gear 11 is a flexible cylindrical member centered on a rotation axis O1, and has teeth on its outer periphery.

[0013] The first internal gear 31G and the second internal gear 32G rotate around the vibration exciter shaft 10, centering on the rotation axis O1. The first internal gear 31G and the second internal gear 32G are arranged side by side in the axial direction and mesh with the external gear 11. Specifically, one of the first internal gear 31G and the second internal gear 32G meshes with teeth on one side of the axial center of the external gear 11, and the other meshes with teeth on the other side of the axial center of the external gear 11. Of these, the first internal gear 31G is configured by providing internal teeth at a corresponding location on the inner periphery of the first internal gear member 31. On the other hand, the second internal gear 32G is configured by providing internal teeth at a corresponding location on the inner periphery of the second internal gear member 32.

[0014] The two vibration exciter bearings 12 are, for example, roller bearings, and are disposed between the vibration exciter 10A and the external gear 11. The vibration exciter 10A and the external gear 11 are capable of relative rotation via the two vibration exciter bearings 12. Each vibrator bearing 12 has a flexible outer ring 123 fitted into the inner circumference of the external gear 11, a plurality of rolling elements (rollers) 122, and a cage 121 that holds the plurality of rolling elements 122. The plurality of rolling elements 122 are arranged in the circumferential direction and roll with the outer peripheral surface of the vibrator 10A and the inner peripheral surface of the outer ring 123 as rolling surfaces. In this embodiment, the outer peripheral surface of the vibrator 10A constitutes the inner ring side rolling surface, but this is not limited thereto, and the vibrator may have an inner ring in addition to 10A. The two vibrator bearings 12 are arranged side by side in the axial direction and include a first vibrator bearing 12A arranged radially inward of the first internal gear 31G and a second vibrator bearing 12B arranged radially inward of the second internal gear 32G. Hereinafter, the components of the first vibrator bearing 12A may be identified by adding the suffix "A" to the components of the second vibrator bearing 12B, and the components of the second vibrator bearing 12B may be identified by adding the suffix "B" to the components (see FIG. 2).

[0015] Restriction members 41, 42 are provided on both axial sides of the vibration exciter bearing 12 and the external gear 11 in contact with them to restrict their axial movement.

[0016] The casing 33 is connected to the first internal gear member 31 by bolts 51, and covers the outer diameter side of the second internal gear 32G. The casing 33 has an outer ring portion of a main bearing 38 (e.g., a cross roller bearing) formed on the inner periphery, and rotatably supports the second internal gear member 32 via the main bearing 38. When the flexible mesh gear device 1 is connected to an external mating device, the casing 33 and the first internal gear member 31 are connected to the mating device by being fastened together.

[0017] The first cover 34 is connected to the first internal gear member 31 by bolts 52, and covers the meshing portion between the external gear 11 and the first internal gear 31G from the non-output side in the axial direction. A bearing 36 (e.g., a ball bearing) is disposed between the first cover 34 and the shaft portion 10B of the vibrator shaft 10, and the first cover 34 rotatably supports the vibrator shaft 10 via the bearing 36.

[0018] The second cover 35 is connected to the second internal gear member 32 by bolts 53, and covers the meshing portion between the external gear 11 and the second internal gear 32G from the axial output side. A bearing 37 (e.g., a ball bearing) is disposed between the second cover 35 and the shaft portion 10C of the vibration exciter shaft 10, and the second cover 35 rotatably supports the vibration exciter shaft 10 via the bearing 37. When the flexible mesh gear device 1 is connected to an external mating device, the second cover 35 and the second internal gear member 32 are fastened together to be connected to a driven member of the mating device, and output reduced rotation to the driven member.

[0019] Furthermore, the flexible mesh gear device 1 includes oil seals 43, 44, and 45 and O-rings 46, 47, and 48 for sealing purposes. The oil seal 43 is disposed at the end on the non-output side in the axial direction, between the shaft portion 10B of the vibrator shaft 10 and the first cover 34, and prevents the outflow of lubricant to the non-output side. The oil seal 44 is disposed at the end on the output side in the axial direction, between the shaft portion 10C of the vibrator shaft 10 and the second cover 35, and prevents the outflow of lubricant to the output side. The oil seal 45 is disposed between the casing 33 and the second internal gear member 32, and prevents the outflow of lubricant from this portion. O-rings 46, 47, 48 are respectively provided between the first internal gear member 31 and the first cover 34, between the first internal gear member 31 and the casing 33, and between the second internal gear member 32 and the second cover 35, to prevent lubricant from leaking out from between them. As a result, the lubricant is sealed within the seal space S inside the flexible mesh gear device 1 which is sealed by the oil seals 43-45 and the O-rings 46-48.

[0020] [Deceleration operation of flexible mesh gear device] Next, the deceleration operation of the flexible mesh gear device 1 will be described. When the vibration exciter shaft 10 is rotated by a driving source such as a motor, the motion of the vibration exciter 10A is transmitted to the external gear 11. At this time, the external gear 11 is restricted to a shape that conforms to the outer circumferential surface of the vibration exciter 10A, and is bent into an elliptical shape having a major axis portion and a minor axis portion when viewed from the axial direction. Furthermore, the external gear 11 is meshed with the fixed first internal gear 31G at the major axis portion. Therefore, the external gear 11 does not rotate at the same rotation speed as the vibration exciter 10A, and the vibration exciter 10A rotates relatively inside the external gear 11. Then, with this relative rotation, the external gear 11 is bent and deformed so that the major axis position and the minor axis position move in the circumferential direction. The period of this deformation is proportional to the rotation period of the vibration exciter shaft 10.

[0021] When the external gear 11 flexes and deforms, the position of its major axis moves, and the meshing position between the external gear 11 and the first internal gear 31G changes in the rotational direction. For example, if the number of teeth of the external gear 11 is 100 and the number of teeth of the first internal gear 31G is 102, the meshing teeth of the external gear 11 and the first internal gear 31G shift each time the meshing position rotates around one revolution, causing the external gear 11 to rotate (spin). With the above number of teeth, the rotational motion of the vibration exciter shaft 10 is reduced at a reduction ratio of 100:2 and transmitted to the external gear 11. In this case, the reduction ratio is "50".

[0022] Meanwhile, since the external gear 11 also meshes with the second internal gear 32G, the meshing position between the external gear 11 and the second internal gear 32G also changes in the rotational direction due to the rotation of the vibration exciter shaft 10. If the number of teeth of the second internal gear 32G and the number of teeth of the external gear 11 are the same, the external gear 11 and the second internal gear 32G do not rotate relative to each other, and the rotational motion of the external gear 11 is transmitted to the second internal gear 32G at a reduction ratio of 1:1. As a result, the rotational motion of the vibration exciter shaft 10 is decelerated at a reduction ratio of 100:2 and transmitted to the second internal gear member 32 and the second cover 35, and this rotational motion is output to the driven member.

[0023] [Structural features of the outer ring of the external gear and the vibration exciter bearing (1)] The flexible mesh gear device 1 has a structural feature in that at least one of the inner circumferential surface of the external gear 11 and the outer circumferential surface of the outer ring 123 of each vibration exciter bearing 12 is made of an oil-retaining material. 2 to 4 show an example in which the outer peripheral surface of the outer ring 123 of each vibration exciter bearing 12 is made of an oil-retaining material. The structural features of the external gear 11 and the outer ring 123 of each vibration exciter bearing 12 will be described in more detail with reference to these drawings.

[0024] 2 is a cross-sectional view perpendicular to the axis of the external gear 11 and the outer ring 123 of the vibration exciter bearing 12. Note that in FIG. 2, the external teeth of the external gear 11 are omitted. 2, each of the outer rings 123 of the vibrator bearing 12 has a layer of an oil-impregnated material (hereinafter referred to as oil-impregnated material layer 124) on the outer circumferential side including the outer circumferential surface, and has a high rigidity layer 125 made of a material having a larger Young's modulus than the oil-impregnated material layer 124 on the radially inner side of the oil-impregnated material layer 124. The inner circumferential surface of the high rigidity layer 125 becomes the rolling surface of the rolling elements 122.

[0025] The high-rigidity layer 125 is made of cast iron or steel (for example, high-carbon chromium bearing steel). The oil-retaining material layer 124 is composed of sintered metal, porous material, oil-retaining resin, etc., and has a smaller Young's modulus than the high rigidity layer 125. However, due to the structure of the material, it can be impregnated with a larger amount of lubricant than the high rigidity layer 125 or the outer ring 123. The oil-retaining material layer 124 may be made of any material, such as sintered metal, porous material, oil-retaining resin, etc., as long as it can ensure appropriate wear resistance against the sliding counterpart member (external gear 11). Here, however, the example shown is made of sintered metal. Moreover, the external gear 11 that slides against the oil-retaining material layer 124 of the outer ring 123 is made of a steel material (for example, a chromium-molybdenum steel material or the like).

[0026] The sintered metal may be formed by any method such as powder sintering, lamination sintering of wire mesh or etched plate, fiber sintering, etc. As the sintered metal material, iron, stainless steel, copper alloy, aluminum alloy, nickel, nickel alloy, titanium, molybdenum, tungsten, tantalum, zirconium boride, etc. may be used, and among these, a material having excellent wear resistance may be selected.

[0027] The oil-impregnated material layer 124 and the high-rigidity layer 125 are integrated by bonding. For example, the inner peripheral surface of the oil-impregnated material layer 124 and the outer peripheral surface of the high-rigidity layer 125 are bonded by diffusion bonding. The bonding between the oil-impregnated material layer 124 and the high-rigidity layer 125 is not limited to diffusion bonding, but is preferably a bonding that involves the disappearance of part or all of the metal coating on the bonding surfaces, and more preferably a bonding that does not involve melting of the materials of the oil-impregnated material layer 124 and the high-rigidity layer 125.

[0028] 3 is an enlarged cross-sectional view taken along the axial direction of the external gear 11 and the outer ring 123 of the vibration exciter bearing 12. In FIG. 3, the upper side is the radially inner side, and the lower side is the radially outer side. As shown in the figure, the oil-impregnated material layer 124 of the outer ring 123 of each vibrator bearing 12 is wider in the axial direction than the rolling elements 122 (their rolling surfaces) that the outer ring 123 carries on the radial inside, and is configured so that, when viewed from the radial direction, the rolling elements 122 (their rolling surfaces) are on the inside of the oil-impregnated material layer 124. As a result, when the long axis position of vibrator 10A moves circumferentially due to rotation of vibrator shaft 10, the outer circumferential surface of outer ring 123 slides against the inner circumferential surface of external gear 11 while being pressed by rolling elements 122. At that time, the entire area pressed by rolling elements 122 is within the range of oil-impregnated material layer 124, so that a sufficient amount of lubricant is secured in the area pressed by rolling elements 122, enabling smooth sliding.

[0029] Furthermore, the oil-retaining material layer 124 has a narrower axial width than the high-rigidity layer 125, and is set so that the oil-retaining material layer 124 is located inside the high-rigidity layer 125 when viewed in the radial direction. In this way, because the oil-retaining material layer 124 has a narrower axial width than the high-rigidity layer 125, gap regions n1 can be formed on both sides of the oil-retaining material layer 124 between the external gear 11 and the outer ring 123. These gap regions n1 serve as lubricant reservoirs, so that lubricant can be stably supplied between the external gear 11 and the outer ring 123, achieving good lubrication.

[0030] Figures 4(A) to 4(C) are enlarged cross-sectional views of region E in Figure 2, and each figure shows an example in which the ratio of radial thickness of oil-impregnated material layer 124 and high rigidity layer 125 of outer ring 123 is different. Figure 4(A) shows an example in which oil-impregnated material layer 124 and high rigidity layer 125 are equal in thickness, Figure 4(B) shows an example in which oil-impregnated material layer 124 is thicker than high rigidity layer 125, and Figure 4(C) shows an example in which high rigidity layer 125 is thicker than oil-impregnated material layer 124. In the example of Fig. 4(B), the oil-impregnated material layer 124 is thicker than the high rigidity layer 125, so a larger amount of lubricant can be stably supplied between the external gear 11 and the outer ring 123. In the example of Fig. 4(C), the high rigidity layer 125 is thicker than the oil-impregnated material layer 124, so the strength of the outer ring 123 can be maintained high. In the example of Fig. 4(A), the oil-impregnated material layer 124 and the high rigidity layer 125 have the same thickness, so it is possible to provide an outer ring 123 with a good balance between strength and lubricity.

[0031] [Structural features of the outer ring of the external gear and the vibration exciter bearing (2)] 5 to 7 show an example in which the inner peripheral surface of the external gear 11 is made of an oil-retaining material. The structural features of the external gear 11 and the outer ring 123 of each vibration exciter bearing 12 will be described in more detail with reference to these drawings.

[0032] 5 is a cross-sectional view perpendicular to the axis of the external gear 11 and the outer ring 123 of the vibration exciter bearing 12. Note that, in the case of FIG. 5 as well, the external teeth of the external gear 11 are omitted from the illustration. As shown in Figure 5, the external gear 11 has a layer of oil-retaining material (hereinafter referred to as oil-retaining material layer 111) on its inner side, including the inner circumferential surface, and has a high-rigidity layer 112 on the radially outer side of the oil-retaining material layer 111, which is made of a material having a higher Young's modulus than the oil-retaining material layer 111.

[0033] The high-rigidity layer 112 is made of a steel material (for example, a chromium-molybdenum steel material or the like), and has external teeth formed on its outer periphery. The oil-impregnating material layer 111 is made of the same sintered metal, porous material, oil-impregnating resin, etc. as the oil-impregnating material layer 124 of the outer ring 123 described above, and here too, the case where it is made of sintered metal is illustrated as an example. Moreover, the oil-retaining material layer 111 and the high-rigidity layer 112 are bonded together by diffusion bonding. Moreover, the outer ring 123 of the vibration exciter bearing 12, which slides against the oil-impregnated material layer 111 of the external gear 11, is entirely made of the material (steel) of the high-rigidity layer 125 described above.

[0034] 6(A) to 6(C) are enlarged cross-sectional views taken along the axial direction of the external gear 11 and the outer ring 123 of the vibration exciter bearing 12. In these figures, the upper side is the radially inner side, and the lower side is the radially outer side. Figure 6(A) shows an example in which an oil-impregnating material layer 111 is integrally provided over almost the entire axial width on the inner periphery of the external gear 11, Figure 6(B) shows an example in which multiple (two) oil-impregnating material layers 111 are provided side by side in the axial direction on the inner periphery of the external gear 11, and Figure 6(C) shows an example in which multiple (two) oil-impregnating material layers 111 are provided side by side in the axial direction on the inner periphery of the external gear 11, and the axial width is narrower than the example of Figure 6(B).

[0035] 6(A), the oil-impregnated material layer 111 of the external gear 11 is provided across the entire width in the axial direction and has the same width as the high-rigidity layer 112. In addition, the oil-impregnated material layer 111 is set so as to occupy an area that includes all of the rolling surfaces of the two rolling elements 122 when viewed from the radial direction. As a result, when the long axis position of the vibrator 10A moves in the circumferential direction due to rotation of the vibrator shaft 10, the oil-impregnated material layer 111 of the external gear 11 is pressed by the rolling elements 122 of the two vibrator bearings 12 via the outer rings 123, causing flexural deformation, and the outer peripheral surfaces of the outer rings 123 slide while pressing against the inner peripheral surface of the oil-impregnated material layer 111 of the external gear 11. At that time, the entire area pressed by the rolling elements 122 is within the range of the oil-impregnated material layer 111, so that a sufficient amount of lubricant is secured in the area pressed by the rolling elements 122, making it possible to achieve smooth sliding.

[0036] 6(B), two oil-retaining material layers 111 are provided via a groove provided in the center in the axial direction. In this case, a gap region n2 can be formed in the groove between the two oil-retaining material layers 111. This gap region n2 serves as a lubricant reservoir, so that lubricant can be stably supplied between the external gear 11 and the outer ring 123, and good lubrication can be achieved. Moreover, each oil-retaining material layer 111 is wider in the axial direction than the rolling elements 122, and is provided in a range that includes each rolling surface when viewed in the radial direction.

[0037] In the configuration of Figure 6 (C), two oil-impregnating material layers 111 are provided via a groove provided in the center in the axial direction, and the overall axial width of the two oil-impregnating material layers 111 (the total width of the two oil-impregnating material layers 111 including the grooves) is made narrower than the overall axial width (total width) of the two outer rings 123. Also in this case, each oil-retaining material layer 111 is wider in the axial direction than the rolling elements 122 and is provided in a range that includes each rolling surface when viewed in the radial direction. In this case, gap regions n2 can be formed on both axially outer sides of the two oil-retaining material layers 111. Therefore, these multiple gap regions n2 serve as lubricant reservoirs, making it possible to more stably supply lubricant between the external gear 11 and the outer ring 123, thereby achieving good lubrication. In the case of the configuration of FIG. 6(C), the gap regions n2 at both ends in the axial direction can be used as lubricant reservoirs, so there is no need to form the gap regions n2 by grooves between the two oil-retaining material layers 111.

[0038] Figures 7(A) to 7(C) are enlarged cross-sectional views of region F in Figure 5, and each figure shows an example in which the ratio of radial thickness of the oil-impregnated material layer 111 and the high rigidity layer 112 of the external gear 11 is different. Figure 7(A) shows an example in which the oil-impregnated material layer 111 and the high rigidity layer 112 are equal in thickness, Figure 7(B) shows an example in which the oil-impregnated material layer 111 is thicker than the high rigidity layer 112, and Figure 7(C) shows an example in which the high rigidity layer 112 is thicker than the oil-impregnated material layer 111. In the example of Fig. 7(B), the oil-retaining material layer 111 is thicker than the high rigidity layer 112, so a larger amount of lubricant can be stably supplied between the external gear 11 and the outer ring 123. In the example of Fig. 7(C), the high rigidity layer 112 is thicker than the oil-retaining material layer 111, so the strength of the external gear 11 can be maintained high. In the example of Fig. 7(A), the oil-retaining material layer 111 and the high rigidity layer 112 are the same thickness, so it is possible to provide an external gear 11 that has a good balance between strength and lubricity.

[0039] [Technical effect of the present embodiment] As described above, according to this embodiment, the flexible meshing gear device 1 has an oil-retaining material layer 111 or 124 on the inner side of the external gear 11 or the outer side of the outer ring 123 of the vibration exciter bearing 12, so that lubricant is more easily retained between the external gear 11 and the outer ring 123 of the vibration exciter bearing 12, and wear between the external gear 11 and the outer ring 123 of the vibration exciter bearing 12 can be suppressed. Furthermore, even if the rotation of the vibrator shaft 10 causes the interface between the external gear 11 and the outer ring 123 of the vibrator bearing 12 to come into strong contact on the long axis side, the oil-retaining material layer 111 or 124 retains the lubricant, so the lubricant will not leak to the outside and become insufficient, making it possible to effectively suppress wear such as fretting. In particular, when the oil-retaining material layers 111, 124 are made of sintered metal, the lubricant can be retained while ensuring strength and wear resistance, making it possible to effectively suppress wear such as fretting for a longer period of time.

[0040] In addition, when the external gear 11 has an oil-retaining material layer 111 on its inner peripheral side and a high rigidity layer 112 on the radially outer side of the oil-retaining material layer 111, the external gear 11 can maintain its strength while also maintaining lubrication between the external gear 11 and the outer ring 123 of the vibration exciter bearing 12. Similarly, in the case of a configuration in which the outer ring 123 of the vibrator bearing 12 has an oil-impregnated material layer 124 on the outer periphery and a high rigidity layer 125 on the radially inner side of the oil-impregnated material layer 124, it is possible for the outer ring 123 to maintain its strength while maintaining lubrication between it and the external gear 11.

[0041] Furthermore, as shown in Figure 6 (B), when multiple oil-impregnated material layers 111 of the external gear 11 are arranged in the axial direction (two in the above embodiment), a gap region n2 is formed between the oil-impregnated material layers 111, and the gap region n2 can be used as a lubricant reservoir, making it possible to further improve the lubrication of the external gear 11 and the outer ring 123 of the vibration exciter bearing 12. Furthermore, as shown in Figure 6 (C), if the overall axial width of the oil-impregnated material layer 111 of the external gear 11 is made narrower than the overall axial width of the outer ring 123 of the vibration exciter bearing 12, gap regions n2 can be provided on both axial outsides of the two oil-impregnated material layers 111 of the external gear 11, and by using these as lubricant reservoirs, it is possible to further improve the lubrication of the external gear 11 and the outer ring 123 of the vibration exciter bearing 12.

[0042] Furthermore, as shown in FIG. 3, when an oil-impregnated material layer 124 is provided on the outer periphery of multiple (two in the above embodiment) outer rings 123 arranged in the axial direction and each oil-impregnated material layer 124 has a wider axial width than the rolling elements 122 that support it radially inward, each oil-impregnated material layer 124 can supply lubricant well to the range where the outer ring 123 and external gear 11 are strongly pressed by each rolling element 122 at the long axis position due to rotation of the vibration exciter shaft 10, so that leakage of lubricant to the outside from between the outer ring 123 and the external gear 11 due to the pressure of each rolling element 122 is effectively prevented, and wear such as fretting can be more effectively prevented.

[0043] Furthermore, when the oil-impregnated material layer 111 or 124 and the high rigidity layer 112 or 125 are joined by diffusion bonding or the like in the outer ring 123 of the external gear 11 or the vibrator bearing 12, unlike fitting by engagement, the circumferential tensile stress or compressive stress applied to the oil-impregnated material layer 111 or 124 can be suppressed, so that the oil-impregnated material layer 111 or 124 can be protected and its strength can be maintained.

[0044] [others] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the above embodiment, a cylindrical meshing gear device has been described as an example of the flexible meshing gear device 1. However, the present invention is not limited to this and can also be suitably applied to, for example, a cup-type or top hat-type flexible meshing gear device. In addition, the details shown in the above embodiment can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0045] 1 Flexible mesh gear device 10 Vibration axis 10A vibrator 10B, 10C shaft part 11 External gear 12 Vibrator bearing 111,124 Oil-impregnated material layer 112,125 High rigidity layer 122 Rolling elements (rollers) 123 Outer Ring O1 Rotational Axis n1 Gap area n2 Gap area

Claims

1. A flexible mesh gear device including a vibration exciter, an external gear that is flexibly deformed by the vibration exciter, and a vibration exciter bearing disposed between the vibration exciter and the external gear, the vibration exciter bearing has an outer ring that fits onto an inner periphery of the external gear, of an inner circumferential surface of the external gear and an outer circumferential surface of the outer ring, at least the outer circumferential surface of the outer ring is made of an oil-retaining material, a high-rigidity layer made of a material having a larger Young's modulus than the oil-impregnating material is provided radially inward of the layer of the oil-impregnating material, and a rolling surface is formed on the inner periphery of the high-rigidity layer; The oil-retaining material layer is formed in a plurality of layers aligned along the axial direction, A flexible mesh gear device having gap regions formed axially between the layers of the oil-impregnating material.

2. A flexible mesh gear device including a vibration exciter, an external gear that is flexibly deformed by the vibration exciter, and a vibration exciter bearing disposed between the vibration exciter and the external gear, the vibration exciter bearing has an outer ring that fits onto an inner periphery of the external gear, At least one of an inner circumferential surface of the external gear and an outer circumferential surface of the outer ring is made of an oil-retaining material, The flexible mesh gear device, wherein the oil-retaining material is a sintered metal.

3. A flexible mesh gear device including a vibration exciter, an external gear that is flexibly deformed by the vibration exciter, and a vibration exciter bearing disposed between the vibration exciter and the external gear, the vibration exciter bearing has an outer ring that fits onto an inner periphery of the external gear, of an inner circumferential surface of the external gear and an outer circumferential surface of the outer ring, at least the inner circumferential surface of the external gear is made of an oil-retaining material, A high-rigidity layer is provided radially outward of the layer of oil-retaining material and is made of a material having a Young's modulus greater than that of the oil-retaining material, and external teeth are formed on the high-rigidity layer. A flexible meshing gear device in which the layer of oil-retaining material of the external gear has an axial width narrower than that of the outer ring.

4. A flexible mesh gear device including a vibration exciter, an external gear that is flexibly deformed by the vibration exciter, and a vibration exciter bearing disposed between the vibration exciter and the external gear, the vibration exciter bearing has an outer ring that fits onto an inner periphery of the external gear, of an inner circumferential surface of the external gear and an outer circumferential surface of the outer ring, at least the outer circumferential surface of the outer ring is made of an oil-retaining material, a high-rigidity layer made of a material having a larger Young's modulus than the oil-impregnating material is provided radially inward of the layer of the oil-impregnating material, and a rolling surface is formed on the inner periphery of the high-rigidity layer; The bearing has a plurality of rolling elements arranged in an axial direction and a plurality of the outer rings arranged in an axial direction, A flexible mesh gear device in which the layers of the oil-retaining material of the outer rings are wider in the axial direction than the rolling elements located radially inward.

5. the inner circumferential surface of the external gear is made of the oil-retaining material, 3. A flexible meshing gear device according to claim 2, further comprising a high-rigidity layer made of a material having a larger Young's modulus than the oil-impregnating material radially outside the layer of oil-impregnating material, and external teeth are formed on the high-rigidity layer.

6. 6. The flexible mesh gear device according to claim 5, wherein the layer of the oil-retaining material of the external gear has an axial width narrower than that of the outer ring.

7. the outer peripheral surface of the outer ring is made of an oil-retaining material, 3. A flexible meshing gear device according to claim 2, further comprising a high rigidity layer made of a material having a larger Young's modulus than the oil-retaining material radially inside the layer of oil-retaining material, and a rolling surface is formed on the inner circumference of the high rigidity layer.

8. 8. The flexible mesh gear device according to claim 1, wherein the boundary surface between the oil-retaining material layer and the high-rigidity layer is joined.

Images