Rotating devices and gear systems

Abstract

The present invention provides a rotating device and a gear device that can reliably connect a rotating body and a race, and that can simplify and miniaturize the bearing structure. [Solution] The reduction gear of the embodiment comprises a case 2 and a carrier 3, and a main bearing 6 that supports the case 2 and the carrier 3 so as to be rotatable relative to each other. The main bearing 6 comprises an outer race 31 and an inner race 32, and rolling elements 33. At least one of the case 2 or the carrier 3 is cast with either the outer race 31 or the inner race 32, and an intermediate layer 50 is formed between the first race joining surface 32c and the second race joining surface 32e and the first substrate joining surface 40a and the second substrate joining surface 40b.

Description

Technical Field

[0001] The present invention relates to a rotating device and a gear device.

Background Art

[0002] Conventionally, as a rotating device or a gear device, there is known one including two rotating bodies and a rolling bearing that enables the two rotating bodies to rotate relative to each other. As the rolling bearing, for example, there is a radial bearing. The radial bearing includes an outer race, an inner race, and a plurality of rolling elements disposed between the outer race and the inner race. For such a gear device, in order to simplify and miniaturize the bearing structure, a technique of integrating the outer race or the inner race with the rotating body has been disclosed (see, for example, Patent Document 1). This one forms a rotating body (support member and disk) with a casting such as spheroidal graphite cast iron, and forms the inner race (inner ring) with a high-carbon chromium bearing steel such as SUJ or a carbon steel such as S55C. Then, these dissimilar members are joined, and the inner race is heat-treated to form a rolling surface for the rolling elements.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, even if an attempt is made to join dissimilar members as in the above-described conventional technology, in practice, the joining becomes incomplete, and there is a possibility that the inner race may fall off from the rotating body. For this reason, there has been a problem that it is difficult to put into practical use for simplifying and miniaturizing the bearing structure.

[0005] The present invention provides a rotating device and a gear device that can surely join a rotating body and a race, and can simplify and miniaturize the bearing structure. [Means for solving the problem]

[0006] A rotating device according to one aspect of the present invention comprises two rotating bodies and a rolling bearing that supports the two rotating bodies so as to be rotatable relative to each other, wherein the rolling bearing comprises two races arranged side by side with the rotating bodies and a plurality of rolling elements arranged between the two races and on the opposite side from the rotating bodies, wherein at least one of the rotating bodies has a race that overlaps with the race, and the race has a race that overlaps with the rotating body and has an intermediate layer provided between the rotating body joint surface and the race joint surface, which is made of a different material from the rotating body and the race.

[0007] This configuration ensures a secure connection between the rotating body and the race via an intermediate layer. This prevents the race from detaching from the rotating body, thus simplifying and miniaturizing the bearing structure.

[0008] In the above configuration, the intermediate layer is electroless nickel plating.

[0009] In the above configuration, the melting point of the intermediate layer is lower than the temperature of the molten rotating body when the race is cast into the rotating body, and also lower than the melting point of the race, while the boiling point of the intermediate layer is higher than the temperature of the molten rotating body, and also higher than the melting point of the race.

[0010] In the above configuration, a protrusion is formed on either the rotating joint surface or the race joint surface, projecting toward the other, and a recess is formed on the other surface into which the protrusion fits.

[0011] Another aspect of the present invention relates to a gear apparatus comprising: a cylindrical case having an internal gear; a carrier disposed radially inside the case and rotatably supported by the case via rolling bearings; at least one crankshaft rotatably supported by the carrier and to which an external rotational force is input; and an oscillating external gear meshing with the internal gear, wherein the crankshaft has a shaft body and an eccentric portion provided on the shaft body and eccentric with respect to the rotation axis of the shaft body; the oscillating external gear is rotatably supported by the eccentric portion; and the rolling bearing comprises an outer race provided on the case and an inner race provided on the carrier and the outer race and the inner race The carrier comprises a plurality of rolling elements arranged between the outer race and the inner race, wherein at least one of the outer race and the inner race is cast into the corresponding case and the carrier, and at least one of the cast outer race and the inner race has a race joint surface that overlaps with the case and the carrier, and at least one of the case and the carrier has a rotating joint surface that overlaps with the outer race and the inner race, and has an intermediate layer provided between the race joint surface and the rotating joint surface, the intermediate layer being formed of a material different from the case, the carrier, the outer race and the inner race.

[0012] This configuration allows for secure bonding of the outer race to the case and the inner race to the carrier via an intermediate layer. Therefore, it is possible to prevent the outer race from falling out of the case, and to prevent the inner race from falling out of the carrier. Thus, the bearing structure can be reliably simplified and miniaturized. [Effects of the Invention]

[0013] The aforementioned rotating device and gear device can reliably connect the rotating body and the race, and the bearing structure can be simplified and miniaturized. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view of a speed reducer according to an embodiment of the present invention. [Figure 2] This is an enlarged view of part II of Figure 1. [Figure 3] This is an explanatory diagram of the manufacturing method for the substrate and inner lace in an embodiment of the present invention. [Figure 4] This is an enlarged cross-sectional view of the main bearing and substrate portion in a modified embodiment of the present invention. [Modes for carrying out the invention]

[0015] Next, embodiments of the present invention will be described with reference to the drawings.

[0016] <Deceleration device> Figure 1 is a cross-sectional view of the reduction gear 1, which is a gear mechanism. As shown in Figure 1, the reduction gear 1 reduces the rotation of, for example, an electric motor (not shown) and outputs the reduced speed. The reduction gear 1 is a so-called eccentric oscillating type reduction gear. The reduction gear 1 comprises a cylindrical case 2, a carrier 3 rotatably mounted radially inside the case 2, and a reduction mechanism 4 connected to the carrier 3. The central axis of the case 2 and the rotation axis of the carrier 3 coincide. In the following explanation, these central axis and rotation axis will be collectively referred to as the first rotation axis A1. The direction parallel to the first rotation axis A1 will be referred to as the axial direction. The rotation direction of carrier 3 will be referred to as the circumferential direction. The radial direction of case 2, which is perpendicular to the axial and circumferential directions, will simply be referred to as the radial direction.

[0017] <Case> Case 2 is made of spheroidal graphite cast iron (ductile cast iron). For example, FCD450 is used as the spheroidal graphite cast iron. An outer flange portion 2a that protrudes radially outward is integrally molded on the outer surface of Case 2. Multiple bolt holes 2b are formed in the outer flange portion 2a. The bolt holes 2b are arranged at equal intervals in the circumferential direction. Bolts (not shown) are inserted into these bolt holes 2b and the reduction gear 1 is fixed by tightening the bolts to, for example, the arm of an industrial robot.

[0018] On the inner peripheral surface 2d of the case 2, a plurality of pin grooves 2c extending in the axial direction are formed. The pin grooves 2c are arranged at equal intervals in the circumferential direction. Inner teeth pins 5 are respectively fitted into the respective pin grooves 2c. The inner teeth pins 5 function as inner teeth that mesh with the oscillating external teeth gears 15 and 16 of the speed reduction mechanism 4, which will be described later. On the inner peripheral surface 2d of the case 2, main bearings 6 are provided on both axial sides respectively. The carrier 3 is rotatably supported by the case 2 via the main bearings 6. The detailed structure of the main bearings 6 will be described later.

[0019] <Carrier> The carrier 3 includes a disk-shaped substrate portion 7 and end plate portions 8 that are arranged opposite to each other in the axial direction, and three column portions 9 that protrude from the substrate portion 7 toward the end plate portions 8. Each of the column portions 9 is arranged at equal intervals in the circumferential direction. The end plate portion 8 is arranged on the tip 9a of the column portion 9. The end plate portion 8 is fixed to the column portion 9 by bolts 10. In this state, a space having a constant width in the axial direction is formed between the substrate portion 7 and the end plate portion 8. Pins 11 are provided radially inside the bolts 10 of the column portions 9. The pins 11 position the end plate portion 8 with respect to the substrate portion 7. The pins 11 are fitted into pin holes 12 provided in the end plate portion 8.

[0020] The substrate portion 7 and the end plate portion 8 are formed of spheroidal graphite cast iron (ductile cast iron). For example, FCD450 is used as the spheroidal graphite cast iron. The outer peripheral surfaces of the substrate portion 7 and the end plate portion 8 are rotatably supported by the case 2 via the corresponding main bearings 6 respectively. Shaft insertion holes 7a and 8a are formed at the radial centers of the substrate portion 7 and the end plate portion 8 respectively. The two shaft insertion holes 7a and 8a are arranged coaxially.

[0021] The base plate portion 7 and the end plate portion 8 each have three crank insertion holes 7b and 8b, respectively, formed between adjacent column portions 9 in the circumferential direction. Each crank insertion hole 7b and 8b is arranged coaxially. That is, the central axis A2 of opposing crank insertion holes 7b and 8b in the axial direction is parallel to the first rotation axis A1. Each crank insertion hole 7b and 8b is provided with a crank bearing 18. The crank bearing 18 is, for example, a tapered roller bearing.

[0022] <Deceleration mechanism> The reduction mechanism 4 reduces the rotation of an electric motor (not shown) by a constant ratio to rotate the carrier 3. The reduction mechanism 4 comprises three crankshafts 13 inserted into each crank insertion hole 7b, 8b, a transmission spur gear (an example of a gear in the claim) 14 provided at the axial end of each crankshaft 13, and two oscillating external gears 15, 16 (first oscillating external gear 15, second oscillating external gear 16) provided between the base plate portion 7 and the end plate portion 8.

[0023] External teeth 17 are formed on the outer circumference of the transmission spur gear 14. The external teeth 17 mesh with, for example, the motor shaft of an electric motor (not shown). This causes the transmission spur gear 14 to rotate.

[0024] The crankshaft 13 is rotatably supported on the carrier 3 (base plate portion 7 and end plate portion 8) via each crank bearing 18. The crankshaft 13 has a shaft body 13c that rotates about a central axis A2, and a first eccentric portion 13a and a second eccentric portion 13b formed in the axial center of the shaft body 13c. Both axial sides of the shaft body 13c are rotatably supported on the carrier 3 (base plate portion 7 and end plate portion 8) via the crank bearings 18. The shaft body 13c and the transmission spur gear 14 are arranged coaxially and integrated. That is, the crankshaft 13 and the transmission spur gear 14 rotate together as a single unit around the central axis A2. Hereinafter, the central axis A2 will be referred to as the second rotation axis A2 of the crankshaft 13.

[0025] The first eccentric portion 13a and the second eccentric portion 13b are eccentric from the second rotation axis A2. The first eccentric portion 13a and the second eccentric portion 13b are positioned adjacent to each other in the axial direction between the two crank bearings 18. In other words, the first eccentric portion 13a and the second eccentric portion 13b are positioned adjacent to each other in the axial direction between the base portion 7 and the end plate portion 8. The first eccentric portion 13a and the second eccentric portion 13b are positioned with a phase angle difference of 180°. The inner circumferential surfaces of roller bearings 19 are fitted to each of the eccentric portions 13a and 13b. The roller bearings 19 are, for example, cylindrical roller bearings. The first oscillating external gear 15 and the second oscillating external gear 16 are rotatably supported on each crankshaft 13 via the roller bearings 19.

[0026] The first oscillating external gear 15 and the second oscillating external gear 16 are positioned in the space between the base plate portion 7 and the end plate portion 8. The first oscillating external gear 15 and the second oscillating external gear 16 have through holes 15a and 16a formed therein, into which the outer circumferential surfaces of the roller bearings 19 are fitted. As a result, when the first eccentric portion 13a and the second eccentric portion 13b oscillate due to the rotation of the crankshaft 13, the first oscillating external gear 15 and the second oscillating external gear 16 oscillate via the roller bearings 19.

[0027] The first oscillating external gear 15 and the second oscillating external gear 16 each have openings 15b and 16b, respectively, to avoid interference with the column portion 9. Shaft insertion holes 15c and 16c are formed at the radial center of the first oscillating external gear 15 and the second oscillating external gear 16. External teeth 15d and 16d are formed on the outer circumference of the first oscillating external gear 15 and the outer circumference of the second oscillating external gear 16, respectively. The number of teeth on each external tooth 15d and 16d is, for example, one less than the number of internal tooth pins 5 of case 2.

[0028] Under this configuration, as the first and second oscillating external gears 15 and 16 oscillate, some of the external teeth 15d and 16d of each gear engage with the internal pin 5 of case 2. The number of teeth on each external tooth 15d and 16d is, for example, one less than the number of internal pins 5. Therefore, each oscillating external gear 15 and 16 rotates such that the engagement points of each external tooth 15d and 16d with respect to the internal pin 5 (case 2) are sequentially shifted in the circumferential direction. This rotation is decelerated relative to the rotation of the crankshaft 13.

[0029] As each oscillating external gear 15, 16 rotates, each crankshaft 13 also rotates on its own axis around the second rotation axis A2 while revolving around the first rotation axis A1. Each crankshaft 13 is rotatably supported on the carrier 3 (base portion 7, end plate portion 8). Therefore, the carrier 3 rotates in conjunction with the revolution of each crankshaft 13. As a result, the reduction gear 1 reduces the rotation of, for example, an electric motor (not shown) and outputs the reduced rotation. If the carrier 3 is fixed to the arm of an industrial robot, for example, the reduction gear 1 can reduce the rotation of, for example, an electric motor (not shown) and output the reduced rotation from the case 2.

[0030] <Main bearing> Next, the detailed structure of the main bearing 6 will be described based on Figures 1 and 2. Figure 2 is an enlarged view of Part II of Figure 1. In Figure 2, the scale has been appropriately changed to make the explanation easier to understand. As shown in Figures 1 and 2, the main bearing 6 that rotatably supports the base plate portion 7 and the main bearing 6 that rotatably supports the end plate portion 8 are arranged symmetrically around a plane along the radial direction. For this reason, in the following explanation, only the main bearing 6 that rotatably supports the base plate portion 7 will be described, and the explanation of the main bearing 6 that rotatably supports the end plate portion 8 will be omitted. Also, in the following explanation, the axial central side of the case 2 (the side with the internal tooth pin 5) may be referred to as the axial inner side, and the side opposite to the axial inner side may be referred to as the axial outer side.

[0031] The main bearing 6 is an angular contact ball bearing, a type of radial ball bearing. The main bearing 6 comprises an annular outer race 31 cast into the case 2, an annular inner race 32 cast into the base portion 7 radially inside the outer race 31, a plurality of rolling elements 33 positioned between the outer race 31 and the inner race 32, and a cage 37 that holds the plurality of rolling elements 33 at equal intervals in the circumferential direction.

[0032] The rolling element 33 is spherical. The retainer 37 is made of, for example, resin. The outer race 31 and inner race 32 are formed from high-carbon chromium bearing steel (SUJ) or carbon steel. For example, S55C is used as the carbon steel. The following description will focus on the case where the outer race 31 and inner race 32 are formed using S55C. Although the outer race 31 and the inner race 32 differ slightly in size, their shapes are symmetrical around the rolling element 33. Therefore, in the following explanation, only the inner race 32 will be described, and the explanation of the outer race 31 will be omitted.

[0033] The inner race 32 has an L-shaped cross-section along the axial direction. That is, the inner race 32 has a rolling surface 32a in which the rolling elements 33 come into contact, an axial inner end surface 32b connected to the axial inner end of the rolling surface 32a, a first race joining surface (an example of a race joining surface in the claim) 32c connected to the radial inner end of the axial inner end surface 32b, a radial outer end surface 32d connected to the radial outer end of the rolling surface 32a, and a second race joining surface (an example of a race joining surface in the claim) 32e connected to the axial outer end of the radial outer end surface 32d.

[0034] The rolling surface 32a is the surface on which the rolling element 33 rolls. The cross-sectional shape of the rolling surface 32a along the axial direction is formed in an arc shape to correspond to the surface of the rolling element 33. The axial inner end face 32b extends radially inward from the rolling surface 32a. The axial inner end face 32b is aligned radially. The first race joint surface 32c extends axially outward from the axially inner end surface 32b. The radially outer end surface 32d extends axially outward from the rolling surface 32a. The radially outer end surface 32d is aligned with the axial direction.

[0035] A recess 40 is formed in the substrate portion 7 into which the inner race 32 configured in this manner is cast to receive the inner race 32. The recess 40 is formed to correspond to the shape of the inner race 32. That is, the recess 40 has a first substrate bonding surface (an example of a rotational bonding surface in the claim) 40a that overlaps with the first race bonding surface 32c, a second substrate bonding surface (an example of a rotational bonding surface in the claim) 40b that overlaps with the second race bonding surface 32e, and a corner portion 40c formed at the connection between the first substrate bonding surface 40a and the second substrate bonding surface 40b.

[0036] The first substrate bonding surface 40a extends parallel to the first race bonding surface 32c. The second substrate bonding surface 40b extends parallel to the second race bonding surface 32e. The corner portion 40c is formed to be recessed in the direction away from the inner race 32.

[0037] Under this configuration, an intermediate layer 50 is formed between the inner race 32 and the substrate portion 7. More specifically, the intermediate layer 50 is formed between the first race bonding surface 32c and the first substrate bonding surface 40a, between the second race bonding surface 32e and the second substrate bonding surface 40b, and between the corner portion 40c and the corner portion of the inner race 32 facing this corner portion 40c.

[0038] The intermediate layer 50 is a metal plating pre-formed on the inner race 32. The metal plating is, for example, electroless nickel plating. The thickness of the intermediate layer 50 is, for example, about 5 to 100 μm.

[0039] <Manufacturing method for substrate and inner lace> Next, the manufacturing methods for the substrate portion 7 and inner lace 32 will be described based on Figure 3. The manufacturing methods for the end plate portion 8 and inner lace 32, and the manufacturing methods for the case 2 and outer lace 31 are the same as those for the substrate portion 7 and inner lace 32, so their explanation will be omitted.

[0040] Figure 3 is an explanatory diagram of the manufacturing method for the substrate portion 7 and the inner lace 32. The dashed line in Figure 3 (details will be described later) has been scaled appropriately to make the explanation easier to understand. As shown in Figure 3, first, the base material 35 of the inner race 32 is placed in a sand mold (not shown). The base material 35 is formed in an annular shape and has a first race joining surface 32c and a second race joining surface 32e. An intermediate layer 50 (electroless nickel plating) is pre-formed on the first race joining surface 32c and the second race joining surface 32e.

[0041] Next, molten FCD450 is poured into a sand mold (not shown) to form the approximate outer shape of the substrate portion 7 (shown by a dashed line in Figure 3), and the base material 35 is cast into the substrate portion 7. Here, the melting point of the base material 35, S55C, is approximately 1600°C to 1720°C. The melting point of the substrate part 7, FCD450, is approximately 1470°C to 1490°C. Thus, since the melting point of S55C is higher than that of FCD450, the base material 35 will not melt even when molten FCD450 is poured into the sand mold.

[0042] Furthermore, the melting point of electroless nickel plating is lower than the temperature of molten FCD450 and also lower than the melting point of S55C. In other words, the melting point of the intermediate layer 50 is lower than the melting point of the substrate 7 (case 2) and also lower than the melting point of the inner lace 32 (outer lace 31). The boiling point of the intermediate layer 50 is higher than the temperature of the molten substrate 7 (case 2) and also higher than the melting point of the inner lace 32 (outer lace 31). Specifically, the melting point of electroless nickel plating is approximately 1350°C.

[0043] Therefore, when molten FCD450 is poured into the sand mold, the intermediate layer 50 is reliably melted without evaporating. The molten intermediate layer 50 also flows sufficiently into the corners 40c of the substrate portion 7. As a result, the molten intermediate layer 50 permeates and spreads throughout the substrate portion 7 and the base material 35, and the intermediate layer 50 is bonded to the substrate portion 7 and the base material 35. In other words, the substrate portion 7 and the base material 35 are reliably bonded via the intermediate layer 50.

[0044] Next, the radially outer surface of the base material 35 is machined using, for example, a lathe (not shown) to form the rolling surface 32a. This forms the inner race 32. The outer circumference, inner circumference, and both axial ends of the base plate 7 are also machined to form the base plate 7. After this, the rolling surface 32a of the inner race 32 is heat-treated to harden it. This completes the manufacturing of the base plate 7 and the inner race 32.

[0045] As described above, the inner race 32 is cast into the base plate 7. Therefore, the base plate 7 and the inner race 32 can be integrated. High-carbon chromium bearing steel (SUJ) or carbon steel (S55C) can be used only in areas where hardness as a rolling bearing is required. This makes it easy to finish the integrated base plate 7 and inner race 32.

[0046] An intermediate layer 50 is formed between the substrate portion 7 and the inner race 32. An intermediate layer 50 is also formed between the case 2 and the outer race 31. More specifically, for example, in the substrate portion 7 and the inner race 32, an intermediate layer 50 is formed between the first race bonding surface 32c of the inner race 32 and the first substrate bonding surface 40a of the substrate portion 7, between the second race bonding surface 32e of the inner race 32 and the second substrate bonding surface 40b of the substrate portion 7, and between the corner of the inner race 32 and the corner of the substrate portion 7 40c. Therefore, by using the intermediate layer 50, the substrate portion 7 and the inner race 32, which are made of different materials, can be reliably joined. By using the intermediate layer 50, the case 2 and the outer race 31 can be reliably joined. Thus, the inner race 32 and the outer race 31 can not be prevented from falling out of the substrate portion 7 or the case 2, and the bearing structure can be reliably simplified and miniaturized.

[0047] Electroless nickel plating is used as the intermediate layer 50. Therefore, the intermediate layer 50 can be easily formed simply by forming electroless nickel plating on each race 31 and 32 in advance. The substrate portion 7 and the inner race 32 can be reliably joined via the intermediate layer 50. The case 2 and the outer race 31 can be reliably joined via the intermediate layer 50. More specifically, the melting point of the electroless nickel plating (intermediate layer 50) is lower than the melting point of the molten substrate 7 (case 2) and also lower than the melting point of the inner race 32 (outer race 31). The boiling point of the electroless nickel plating is higher than the melting point of the molten substrate 7 (case 2) and also higher than the melting point of the inner race 32 (outer race 31). Therefore, the intermediate layer 50 can be reliably melted. It is also possible to prevent the intermediate layer 50 from evaporating.

[0048] The present invention is not limited to the embodiments described above, but includes various modifications to the embodiments described above, without departing from the spirit of the invention.

[0049] For example, the above embodiment described a case in which the reduction gear 1 employs the configuration of the main bearing 6. However, it is not limited to this, and the configuration of the main bearing 6 can be employed in various reduction gears, and can be employed in various rotating devices that use rolling bearings instead of the reduction gear 1, or in gear devices that have gears.

[0050] In the above-described embodiment, the case in which the reduction gear 1 comprises three crankshafts 13 was explained. The case in which each oscillating external gear 15, 16 is oscillating and rotating by the three crankshafts 13 was explained. However, it is not limited to this, and when configured as a reduction gear 1, it is sufficient to have at least one crankshaft 13. For example, the reduction gear 1 may be a so-called center-crank type reduction gear comprising one crankshaft 13. In this case, the one crankshaft 13 is arranged coaxially with the first rotation axis A1, and each oscillating external gear 15, 16 is oscillating and rotating by the one crankshaft 13.

[0051] In the above-described embodiment, the main bearing 6 was described as an angular contact ball bearing, a type of radial ball bearing. However, it is not limited to this, and the above configuration of the main bearing 6 can be adopted for various types of rolling bearings. Rolling bearings may include radial roller bearings in addition to radial ball bearings. In other words, the rolling elements 33 are not limited to spheres, but may also be cylindrical rollers. In addition, rolling bearings also include thrust bearings.

[0052] In the embodiments described above, the case 2, the substrate portion 7, and the end plate portion 8 were described in the case where they are each formed from spheroidal graphite cast iron. For example, the case in which FCD450 is used as the spheroidal graphite cast iron was described. The case in which the outer race 31 and inner race 32 are formed from high-carbon chromium bearing steel or carbon steel was described. For example, the case in which S55C is used as the carbon steel was described. The case in which electroless nickel plating is used as the intermediate layer 50 was described.

[0053] However, the process is not limited to this, and various materials can be used for the case 2, substrate portion 7, end plate portion 8, outer race 31, inner race 32, and intermediate layer 50. Metal plating other than electroless nickel plating may be used for the intermediate layer 50. It is preferable that the melting point of the metal plating is lower than the temperature of the molten case 2 and carrier 3 when the outer race 31 and inner race 32 are cast into the case 2 and carrier 3, respectively, and also lower than the melting point of the outer race 31 and inner race 32. It is preferable that the boiling point of the metal plating is higher than the temperature of the molten case 2 and carrier 3, and also higher than the melting points of the outer race 31 and inner race 32. This configuration ensures that the intermediate layer 50 can be reliably melted, and prevents the intermediate layer 50 from evaporating.

[0054] In the above-described embodiment, the case in which the outer race 31 is cast into the case 2 and the inner race 32 is cast into the base plate portion 7 and the end plate portion 8 respectively was explained. However, it is not limited to this, and it is sufficient that the outer race 31 or inner race 32 is cast into at least one of the case 2, the base plate portion 7, and the end plate portion 8. It is sufficient that an intermediate layer 50 is formed at least between the base plate portion 7 and the inner race 32, or between the case 2 and the outer race 31.

[0055] In the embodiments described above, the inner race 32 was described as having a first race bonding surface 32c and a second race bonding surface 32e as race bonding surfaces that overlap with the carrier 3. The carrier 3 was described as having a first substrate bonding surface 40a and a second substrate bonding surface 40b as rotational bonding surfaces that overlap with the inner race 32. However, the invention is not limited to these, and various shapes can be used for the race bonding surfaces and rotational bonding surfaces. These will be described in detail below.

[0056] [Differentiation] Figure 4 is an enlarged cross-sectional view of the main bearing 6 and the substrate portion 7 in a modified example. Figure 4 corresponds to Figure 2 described above. The scale of Figure 4 has been appropriately changed to make the explanation easier to understand. In the following modified examples, only the inner race 32 and the substrate portion 7 will be described. However, the configurations of the inner race 32 and the substrate portion 7 can be applied to the inner race 32 and end plate portion 8, the case 2 and the outer race 31, as in the embodiments described above.

[0057] As shown in Figure 4, the inner race 32 has a rolling surface 32a, an axial inner end surface 32b, a first race joining surface 32c, a radial outer end surface 32d, a second race joining surface 32e, and a rounded chamfered surface 32f formed at the connection between the first race joining surface 32c and the second race joining surface 32e. A protrusion 34 is formed on the first race joining surface 32c over its entire axial length. The protrusion 34 projects radially inward. More specifically, the protrusion 34 is inclined to project gradually radially inward (towards the substrate portion 7) as it moves from the axial inner end surface 32b outward in the axial direction.

[0058] The second race joint surface 32e is inclined to gradually protrude outward in the axial direction as it moves radially inward from the radially outer end surface 32d. In other words, a protrusion 38 is also formed on the second race joint surface 32e. The inclination angle θ2 of the second race joint surface 32e with respect to the radial direction is greater than the inclination angle θ1 of the protrusion 34 with respect to the axial direction. More specifically, the inclination angle θ1 is, for example, about 1° to 10°. The inclination angle θ2 is, for example, about 5° to 30°.

[0059] The rounded chamfered surface 32f connects the axial outer end of the first race joint surface 32c and the radial inner end of the second race joint surface 32e. The rounded chamfered surface 32f is formed in an arc shape.

[0060] The recess 40 formed in the substrate portion 7 is formed to correspond to the shape of the inner race 32. That is, the recess 40 has a first substrate bonding surface 40a, a second substrate bonding surface 40b, and a substrate chamfer surface 40d that overlaps with the rounded chamfer surface 32f.

[0061] The first substrate bonding surface 40a is inclined such that the depth of the recess 40 gradually increases as it moves outward in the axial direction, that is, the outer diameter of the recess 40 decreases. The second substrate bonding surface 40b is inclined such that the depth of the recess 40 gradually increases as it moves inward in the radial direction, that is, it moves outward in the axial direction. Due to the second race bonding surface 32e and the second substrate bonding surface 40b, the substrate portion 7 covers the inner race 32 from the radially outside on the side of the second race bonding surface 32e of the inner race 32.

[0062] An intermediate layer 50 is formed between the convex portions 34, 38 and the rounded chamfered surface 32f of the inner race 32 configured in this way, and the first substrate bonding surface 40a, the second substrate bonding surface 40b, and the rounded chamfered surface 32f of the recess 40.

[0063] With this configuration, when the base material 35 (see Figure 3) of the inner race 32 is cast into the substrate portion 7, the convex portion 34 of the base material 35 fits into the concave portion 40 of the substrate portion 7. This prevents the base material 35 from moving inward in the axial direction relative to the substrate portion 7. A second substrate bonding surface 40b of the substrate portion 7 is formed on the axial outer side of the base material 35. This also prevents the base material 35 from moving outward in the axial direction relative to the substrate portion 7. In this way, the convex portions 34, 38, the concave portion 40, and the second substrate bonding surface 40b prevent the base material 35 from moving in the axial direction relative to the substrate portion 7.

[0064] Here, the thermal expansion coefficient of S55C is 11.7 × 10⁻⁶. -6 The thermal expansion coefficient of FCD450 is 12 × 10⁻⁶. -6The thermal expansion coefficient is / K. Thus, the thermal expansion coefficient of FCD450 is greater than that of S55C. As a result, when the substrate portion 7 is cooled, the substrate portion 7 shrinks more than the base material 35. On the second race bonding surface 32e side of the inner race 32, the substrate portion 7 covers the inner race 32 from the radially outward side. Therefore, as the substrate portion 7 shrinks, the inner race 32 is pressed radially inward by the substrate portion 7. Thus, radial rattle of the base material 35 relative to the substrate portion 7 is prevented, as is rotation of the base material 35 relative to the substrate portion 7.

[0065] Therefore, according to the above-described modification, the same effects as those of the previously described embodiment can be achieved. In addition, in the above-described modification, a protrusion 34 is formed on the first race bonding surface 32c of the inner race 32. A recess 40 is formed in the base plate 7 into which the protrusion 34 fits. Therefore, the inner race 32 can be prevented from falling off the base plate 7 more reliably. Thus, the bearing structure can be reliably simplified and miniaturized.

[0066] The inner race 32 has a second race bonding surface 32e formed thereon. The substrate portion 7 has a second substrate bonding surface 40b that overlaps with the second race bonding surface 32e. The protrusion 34 is inclined so that it gradually protrudes radially inward (towards the substrate portion 7) as it moves outward in the axial direction (towards the second substrate bonding surface 40b). This configuration increases the rigidity of the protrusion 34 and recess 40. This reliably prevents the inner race 32 from moving axially relative to the substrate portion 7. Therefore, it is possible to more reliably prevent the inner race 32 from falling off the substrate portion 7.

[0067] The second race bonding surface 32e and the second substrate bonding surface 40b are inclined so that they gradually extend outward in the axial direction as they move inward in the radial direction. As a result, on the side of the inner race 32 facing the second race bonding surface 32e, the substrate portion 7 covers the inner race 32 from the radially outside. Therefore, radial movement of the inner race 32 relative to the substrate portion 7 can be prevented. Thus, the inner race 32 can be more reliably prevented from falling off the substrate portion 7.

[0068] The radial inclination angle θ2 of the second race bonding surface 32e and the second substrate bonding surface 40b is greater than the axial inclination angle θ1 of the protrusion 34 and the first substrate bonding surface 40a. Therefore, axial movement of the inner race 32 relative to the substrate 7 can be prevented while more reliably preventing radial movement of the inner race 32 relative to the substrate 7.

[0069] In the above-described modification, the case where the protrusion 34 is formed over the entire axial length of the first race joint surface 32c was explained. The case where the protrusion 34 is inclined to project gradually radially inward as it moves from the axially inner end surface 32b outward in the axial direction was explained. However, the design is not limited to this, and various shapes can be adopted for the protrusion 34 and the recess 40.

[0070] For example, the case where the convex portion 34 and the concave portion 40 are inclined has been described. However, the convex portion 34 and the concave portion 40 may also be formed in a curved shape. The convex portion 34 and the concave portion 40 may also be formed in a stepped shape. Even in the case of a stepped shape, the convex portion 34 is formed to protrude radially inward as it moves outward in the axial direction. In addition, various shapes can be adopted for each of the convex portions 34 and 38.

[0071] Among the embodiments disclosed herein, those composed of multiple objects may be integrated, and conversely, those composed of a single object may be divided into multiple objects. Whether or not they are integrated, the invention can be constructed in a way that achieves its objective. [Explanation of Symbols]

[0072] 1…Reduction device (rotating device, gear device) 2…Case (rotating body) 3…Carrier (rotating body) 6…Main bearing (rolling bearing) 7…Circuit board (rotating body) 8…End plate section (rotating body) 13…Crankshaft 13a...First eccentric part (eccentric part) 13b…Second eccentric part (eccentric part) 13c... Shaft body 15…First oscillating external gear (oscillating external gear) 16…Second oscillating external gear (oscillating external gear) 31…Outer race (race) 32... Inner race (race) 32c...First race joint surface (race joint surface) 32e...Second race joint surface (race joint surface) 33... Rolling element 34…Convex part 40…recess 40a...First substrate bonding surface (rotational body bonding surface) 40b...Second substrate bonding surface (rotational body bonding surface) 50…Middle class A1…First rotation axis A2…Second axis of rotation (axis of rotation)

Claims

1. Two solids of revolution, A rolling bearing supports the two rotating bodies so that they can rotate relative to each other, Equipped with, The aforementioned rolling bearing is Two races are arranged alongside the aforementioned rotating body, Between the two races and on the opposite side from the rotating body, a plurality of rolling elements are provided. Equipped with, The race is cast into at least one of the rotating bodies, The rotating body has a rotating body joining surface that overlaps with the race, The race has a race joining surface that overlaps with the rotating body, An intermediate layer is provided between the rotating body joining surface and the race joining surface, and is made of a material different from the rotating body and the race. Rotating device.

2. The aforementioned intermediate layer is electroless nickel plating. The rotating device according to claim 1.

3. The melting point of the intermediate layer is lower than the temperature of the molten rotating body when the race is cast into the rotating body, and also lower than the melting point of the race. The boiling point of the intermediate layer is higher than the temperature of the molten rotating body and higher than the melting point of the lace. The rotating device according to claim 1 or claim 2.

4. Either the rotating joint surface or the race joint surface has a projection that extends toward the other, and the other surface has a recess into which the projection fits. A rotating device according to claim 1 or claim 2.

5. A cylindrical case having an internal gear, A carrier is positioned radially inside the case and is rotatably supported by the case via rolling bearings, The carrier is rotatably supported and to which an external rotational force is input is at least one crankshaft, The oscillating external gear meshes with the aforementioned internal gear, Equipped with, The aforementioned crankshaft is The shaft body and An eccentric portion is provided on the shaft body and is eccentric with respect to the rotation axis of the shaft body, It has, The oscillating external gear is rotatably supported in the eccentric portion, The aforementioned rolling bearing is, An outer race provided in the aforementioned case, An inner race provided on the carrier, A plurality of rolling elements are arranged between the outer race and the inner race, Equipped with, At least one of the outer race and the inner race is cast into the corresponding case and the carrier. At least one of the cast outer race and the inner race has a race joint surface that overlaps with either the case or the carrier. At least one of the case and the carrier has a rotating joint surface that overlaps with either the outer race or the inner race. An intermediate layer is provided between the race joint surface and the rotating body joint surface, The intermediate layer is formed of a material different from the case, the carrier, the outer lace, and the inner lace. Gear mechanism.

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