Speed reducer and wind power generator

Abstract

To provide a speed reducer capable of reducing a necessary load capacity of a main bearing.SOLUTION: A speed reducer includes: a crankshaft 72; a plurality of external gears 74A to 74D swung by the crankshaft 72; an output rotary body 80 including an output side carrier 78 which can be synchronized with rotation components of the external gears 74A to 74D; and an output shaft 42 connected with the output side carrier 78. Therein, the plurality of external gears 74A to 74D constitute a first gear set arranged on an input side and a second gear set arranged on an output side, an alignment sequence of an eccentric phase of each of the external gears 74A to 74D becomes symmetric in an axial direction in the first gear set and the second gear set, can transmits torque, and includes a first connection mechanism 120 which connects the output side carrier 78 and the output shaft 42 so as to permit a relative movement in a direction parallel to an axial direction orthogonal surface.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a speed reducer.

Background Art

[0002] Patent Document 1 discloses an eccentric swing type speed reducer including a crankshaft having an eccentric portion, four external gear wheels swung by the eccentric portion, an internal gear wheel meshing with the external gear wheels, and an output rotating body including an output side carrier capable of synchronizing with the rotation component of the external gear wheels. The four external gear wheels include two outer external gear wheels having the same eccentric phase on both outer sides in the axial direction and two inner external gear wheels having the same eccentric phase on the central side in the axial direction. The eccentric phases of the outer external gear wheels and the inner external gear wheels are shifted by 180°. Thereby, a moment acting on the output rotating body is suppressed due to a shift in the axial position between the resultant force of the loads acting on the output rotating body from the two outer external gear wheels and the resultant force of the loads acting on the output rotating body from the two inner external gear wheels.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the inventor of the present application studied the speed reducer of Patent Document 1, the following new recognition was obtained. The output rotating body is usually supported by a main bearing. From the viewpoint of reducing the outer diameter of the main bearing, a structure for suppressing the moment acting on the output rotating body as in Patent Document 1 is desirable.

[0005] Here, there are cases where the output shaft is connected to the output-side carrier and rotation is output to the outside from the output shaft. In this case, when a radial external load is applied to the output shaft, usually, the external load is directly transmitted to the output rotating body including the output-side carrier. As a result, the required load capacity of the main bearing increases, and even if the structure as in Patent Document 1 is adopted, the outer diameter of the main bearing becomes larger.

[0006] Therefore, one of the objects of the present disclosure is to provide a speed reduction device capable of reducing the required load capacity of the main bearing.

Means for Solving the Problems

[0007] The speed reduction device of the present disclosure includes a crankshaft having an eccentric portion, a plurality of external gear wheels swung by the eccentric portion, an output rotating body including an output-side carrier synchronizable with the rotation component of the external gear wheels, and an output shaft connected to the output-side carrier, and is a speed reduction device comprising: the plurality of external gear wheels constitute a first gear set arranged on the input side and a second gear set arranged on the output side; when the number of external gear wheels constituting each of the gear sets is N, each of the first gear set and the second gear set is composed of a plurality of external gear wheels with an eccentric phase shift of 360° / N (N is a natural number of 2 or more); the first gear set and the second gear set have the arrangement order of the eccentric phases of the external gear wheels symmetric in the axial direction, and are capable of transmitting torque, and are provided with a first connection mechanism for connecting the output-side carrier and the output shaft so as to allow relative movement in a direction parallel to the plane orthogonal to the axial direction.

Advantages of the Invention

[0008] According to the speed reduction device of the present disclosure, the required load capacity of the main bearing can be reduced.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments for implementing the reduction device of the present disclosure will be described. The same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted. In each drawing, for convenience of explanation, components are appropriately omitted, enlarged, or reduced. The drawings are to be viewed in accordance with the direction of the reference numerals.

[0011] Refer to FIG. 1. A wind turbine 10 in which the speed reducer of the present embodiment is used will be described. The wind turbine 10 includes a tower 12 serving as a support column, a nacelle 14 provided at the upper end of the tower 12, a hub 16 rotatably attached to the nacelle 14, and a plurality of blades 18 attached to the hub 16. The hub 16 is rotatable by the wind received by the plurality of blades 18. Inside the nacelle 14, in addition to a speed increaser that increases the rotation speed of the hub 16, a generator that generates electricity by the rotation is accommodated.

[0012] Refer to FIGS. 2 and 3. In FIG. 3, the tower 12 is shown by the pitch circle of a gear 22 (described later), and the drive device 24 is shown by the pitch circle of an output pinion 26 (described later). The nacelle 14 is rotatably supported with respect to the tower 12 via a bearing 20. A gear 22 is provided on the tower 12, and a plurality of drive devices 24 are fixed to the nacelle 14. The drive device 24 of the present embodiment is used as a yaw drive device that rotates the nacelle 14 with respect to the tower 12. The drive devices 24 are arranged in the circumferential direction around the rotation center line C14 of the nacelle 14. The drive device 24 includes an output pinion 26 that meshes with the gear 22. By rotating the output pinion 26 and receiving a reaction force from the gear 22, the output pinion 26 revolves around the rotation center line C14 of the nacelle 14, whereby the nacelle 14 can rotate around the rotation center line C14 with respect to the tower 12.

[0013] Refer to FIG. 4. In FIG. 4 and the like, the bolt may be shown by the center line of the bolt. The drive device 24 includes a motor 32 having a motor shaft 30 and a speed reducer 34 to which the rotation of the motor shaft 30 is input. A first crank shaft 52 (described later) serving as the input shaft of the speed reducer 34 and the motor shaft 30 are connected by a coupling 36. The drive device 24 of the present embodiment is used in a posture such that the motor 32 is located above the speed reducer 34.

[0014] The speed reduction device 34 includes a multi-stage speed reduction mechanism 38, 40 that reduces the rotation of the motor shaft 30, an output shaft 42 that outputs the rotation reduced by the multi-stage speed reduction mechanism 38, 40, output shaft bearings 44A, 44B that support the output shaft 42, a coupling 36, and a casing 46 that houses the coupling 36, the multi-stage speed reduction mechanism 38, 40, and the output shaft 42.

[0015] The multi-stage speed reduction mechanism 38, 40 includes a first speed reduction mechanism 38 on the input side and a second speed reduction mechanism 40 on the output side. An output pinion 26 is provided on the output shaft 42. The rotation of the output shaft 42 is output to a gear 22 that meshes with the output pinion 26.

[0016] The output shaft bearings 44A, 44B are disposed between the output shaft 42 and the casing 46. The output shaft bearings 44A, 44B include a first output shaft bearing 44A disposed on the input side with respect to the output pinion 26 and a second output shaft bearing 44B disposed on the output side with respect to the output pinion 26. The output shaft bearings 44A, 44B of the present embodiment are configured by double-row angular contact bearings, but specific examples thereof are not particularly limited, and various bearings may be employed. The output shaft bearings 44A, 44B of the present embodiment include an outer ring separate from the casing 46 and an inner ring separate from the output shaft 42. In addition, the output shaft 42 may also serve as the inner ring of the output shaft bearings 44A, 44B, or the casing 46 may also serve as the outer ring thereof.

[0017] The casing 46 is configured by combining a plurality of casing members 48 that divide the casing 46. The plurality of casing members 48 are detachably integrated by bolts or the like.

[0018] Referring to FIG. 5. The first speed reduction mechanism 38 of the present embodiment is an eccentric swing type speed reduction mechanism. The first speed reduction mechanism 38 includes a first crankshaft 52 having an eccentric portion 50, a first external gear 54 that swings by the eccentric portion 50, a first internal gear 56 that meshes with the first external gear 54, and an intermediate output shaft 60 that extracts the rotation reduced by the gear mechanism constituted by the first external gear 54 and the first internal gear 56 via a first internal pin 58.

[0019] The rotation of the motor shaft 30 is input to the first crankshaft 52. When the first crankshaft 52 rotates, the first external gear 54 swings due to the eccentric portion 50 of the first crankshaft 52, causing the first external gear 54 to rotate on its own, and the rotation component of the first external gear 54 is extracted by the intermediate output shaft 60. The intermediate output shaft 60 extracts a rotation that is decelerated compared to the rotation of the first crankshaft 52 and outputs it to the second reduction mechanism 40.

[0020] Refer to FIG. 6. The second reduction mechanism 40 of this embodiment is an eccentric swing type reduction mechanism. The second reduction mechanism 40 includes a second crankshaft 72 having eccentric portions 70A to 70D, a plurality of second external gears 74A to 74D that swing due to the eccentric portions 70A to 70D of the second crankshaft 72, a second internal gear 76 that meshes with the second external gears 74A to 74D, and an output rotating body 80 including an output side carrier 78 that can be synchronized with the rotation components of the second external gears 74A to 74D. One of the main features of the reduction device 34 of this embodiment lies in the second external gears 74A to 74D and the output side carrier 78, which will be described first from the peripheral structure.

[0021] The second reduction mechanism 40 of this embodiment is a center crank type in which the second crankshaft 72 is provided on the swing center C74a of the second external gears 74A to 74D. Hereinafter, the direction along the swing center C74a of the second external gears 74A to 74D is simply referred to as the axial direction, and the radial direction and the circumferential direction with respect to the radius direction and the circumferential direction of the circle centered on the swing center C74a are also simply referred to as the radial direction and the circumferential direction, respectively. Also, in the reduction device 34, the side where the output shaft 42 is located with respect to the output rotating body 80 in the axial direction (the lower side of the paper surface in FIG. 6) is referred to as the output side, and the side opposite to it in the axial direction (the upper side of the paper surface in FIG. 6) is referred to as the input side.

[0022] In addition to the plurality of eccentric portions 70A to 70D, the second crankshaft 72 includes shaft portions 82A and 82B provided on both axial sides of the plurality of eccentric portions 70A to 70D. The second crankshaft 72 of the present embodiment includes a total of four eccentric portions 70A to 70D. The eccentric portions 70A to 70D have a circular cross-sectional shape centered on an axis C70 eccentric with respect to the rotation center line C72 of the second crankshaft 72. By rotating around the rotation center line C72 of the second crankshaft 72, the eccentric portions 70A to 70D can swing the second external gear wheels 74A to 74D. Here, "swing" means that the gear center C74b, which is the rotation center of the second external gear wheels 74A to 74D, rotates around the swing center C74a.

[0023] The geometric centers of the cross-sections perpendicular to the axial direction of the shaft portions 82A and 82B are provided coaxially with the rotation center line C72 of the second crankshaft 72. The shaft portions 82A and 82B include an input-side shaft portion 82A provided on the input side with respect to the plurality of eccentric portions 70A to 70D and an output-side shaft portion 82B provided on the output side with respect to the plurality of eccentric portions 70A to 70D. Crankshaft bearings 84 for supporting the second crankshaft 72 are arranged on the respective shaft portions 82A and 82B. The input-side end of the input-side shaft portion 82A of the present embodiment is connected to the intermediate output shaft 60.

[0024] The second external gear wheels 74A to 74D are provided corresponding to the respective plurality of eccentric portions 70A to 70D of the second crankshaft 72 and are supported by the corresponding eccentric portions 70A to 70D via eccentric bearings 86. The eccentric bearings 86 are arranged between the second external gear wheels 74A to 74D and the second crankshaft 72. The eccentric bearing 86 includes a plurality of rolling elements 86a, and an inner ring 86b and an outer ring 86c on which the plurality of rolling elements 86a roll. The rolling elements 86a of the present embodiment are rollers, but various rolling elements such as spheres may be used. The inner ring 86b of the present embodiment is provided separately from the second crankshaft 72, but the second crankshaft 72 may also serve as the inner ring 86b. The outer ring 86c of the present embodiment is also served by the second external gear wheels 74A to 74D, but may be provided separately from the second external gear wheels 74A to 74D.

[0025] The second internal gear 76 includes a second internal gear main body 76a and a second internal gear 76b provided on the inner peripheral portion of the second internal gear main body 76a. The second internal gear main body 76a of this embodiment also serves as the casing 46 by being integrated with the casing 46, but it may be separate from the casing 46. The second internal gear 76b of this embodiment is composed of pins with a circular cross-section that are rotatably supported by pin grooves provided in the second internal gear main body 76a, but it may also be integrally provided by the same member as the second internal gear main body 76a.

[0026] The output rotating body 80 includes, in addition to the output-side carrier 78, an input-side carrier 88 that is arranged on the side opposite to the output-side carrier 78 in the axial direction with respect to the second external gears 74A to 74D, and a plurality of pins 90, 92 that protrude axially from the output-side carrier 78 and penetrate the external gears 74A to 74D. The output rotating body 80 is housed in the casing 46. A main bearing 94, which will be described later, is arranged between the output rotating body 80 and the casing 46.

[0027] The output-side carrier 78 is arranged on the output side with respect to the second external gears 74A to 74D, and the input-side carrier 88 is arranged on the input side with respect to the second external gears 74A to 74D. Each carrier 78, 88 is provided with a crankshaft hole 96 through which the second crankshaft 72 is inserted. The aforementioned crankshaft bearing 84 is arranged between the crankshaft holes 96 of each carrier 78, 88 and the second crankshaft 72.

[0028] The pins 90, 92 include a carrier pin 90 that cooperates with a bolt 98 to connect the output-side carrier 78 and the input-side carrier 88, and a second internal pin 92 that can transmit the rotation component of the second external gears 74A to 74D to the output-side carrier 78. Each of the carrier pin 90 and the second internal pin 92 is provided at positions offset radially with respect to the swing center C74a and spaced apart in the circumferential direction. The carrier pin 90 penetrates the first through holes 100 of the second external gears 74A to 74D, and the second internal pin 92 penetrates the second through holes 102 of the second external gears 74A to 74D.

[0029] The carrier pin 90 does not directly or indirectly contact the first through holes 100 of the second external gear wheels 74A to 74D and does not contribute to the transmission of the rotation component of the second external gear wheels 74A to 74D. In contrast, the second inner pin 92 directly or indirectly contacts the second through holes 102 of the second external gear wheels 74A to 74D and contributes to the transmission of the rotation component of the second external gear wheels 74A to 74D. Here, contributing or not contributing to the transmission of the rotation component of the second external gear wheels 74A to 74D means that when the second external gear wheels 74A to 74D rotate as they swing, it contributes or does not contribute to the transmission of the rotation component to the output carrier 78 on the output side. Also, here, the second inner pin 92 indirectly contacting the second through hole 102 means, for example, the case where it contacts the second through hole 102 via the roller 104 through which the second inner pin 92 is inserted as in this embodiment. In addition to this, the roller 104 may be omitted and the second inner pin 92 may directly contact the second through hole 102. The output rotating body 80 can be synchronized with the rotation component of the second external gear wheels 74A to 74D by the second inner pin 92 during the operation of the speed reduction device 34.

[0030] An example of the operation of the speed reduction device 34 described above will be explained. When the rotation of the motor shaft 30 is input to the speed reduction device 34, it is decelerated by the multi-stage speed reduction mechanisms 38 and 40, and then the rotation is output from the output shaft 42 to the gear 22. In this process, in the second speed reduction mechanism 40, the rotation is input from the intermediate output shaft 60 of the first speed reduction mechanism 38 to the second crankshaft 72. When the second external gear wheels 74A to 74D swing due to the eccentric portions 70A to 70D of the second crankshaft 72, the meshing position between the second external gear wheels 74A to 74D and the second internal gear 76 changes in the circumferential direction. Along with this, every time the second crankshaft 72 makes one rotation, the second external gear wheels 74A to 74D rotate, and the rotation component thereof is taken out by the output rotating body 80. At this time, the rotation component decelerated compared to the rotation of the second crankshaft 72 is taken out by the output rotating body 80.

[0031] Move on to the description of the second external gear wheels 74A to 74D. Refer to FIG. 7. The plurality of second external gear wheels 74A to 74D constitute a first gear set 110 arranged on the input side and a second gear set 112 arranged on the output side. Each of the gear sets 110 and 112 in this embodiment is composed of a total of two second external gear wheels 74A to 74D. The first gear set 110 consists of a first outer external gear wheel 74A on the outer side in the axial direction and a first inner external gear wheel 74B on the inner side in the axial direction. The second gear set 112 consists of a second inner external gear wheel 74C on the inner side in the axial direction and a second outer external gear wheel 74D on the outer side in the axial direction. Here, the inner side in the axial direction regarding the second external gear wheels 74A to 74D refers to the side approaching the central position between the first gear set 110 and the second gear set 112 in the axial direction, and the outer side in the axial direction refers to the side moving away from the central position in the axial direction.

[0032] When the number of the second external gear wheels 74A to 74D constituting each of the first gear set 110 and the second gear set 112 is N (N is a natural number of 2 or more), each of the first gear set 110 and the second gear set 112 consists of a plurality of second external gear wheels 74A to 74D whose eccentric phases are shifted by 360° / N. Here, the eccentric phase refers to the phase around the swing center C74a in the maximum eccentric direction F1 from the swing center C74a of the second external gear wheels 74A to 74D toward the gear center C74b. This eccentric phase is the same as the eccentric phase of the eccentric portions 70A to 70D that swing the second external gear wheels 74A to 74D. The eccentric phase of the eccentric portions 70A to 70D refers to the phase around the rotation center line C72 in the maximum eccentric direction from the rotation center line C72 of the second crankshaft 72 toward the axes C70 of the eccentric portions 70A to 70D. The eccentric phases of the second external gear wheels 74A to 74D of each of the gear sets 110 and 112 in this embodiment are shifted by 180° (= 360° / 2). The eccentric phases of the outer external gear wheels 74A and 74D and the inner external gear wheels 74B and 74C are opposite to each other. The condition that the eccentric phases are shifted here, in addition to the case where the eccentric phases are shifted by a value that matches the mentioned value (for example, 180°), also includes the case where the eccentric phases are shifted by a value that approximately matches the mentioned value (for example, 180° ± several degrees) and is treated as satisfying the condition.

[0033] The second external gear wheels 74A to 74D are provided with second through holes 102 through which the aforementioned second inner pins 92 pass. The second through holes 102 of the respective second external gear wheels 74A to 74D that make up the gear sets 110 and 112 are in rotationally symmetric positions shifted by 360° / N with respect to the swing center 74a. For example, the second through holes 102 of the first outer external gear wheel 74A and the first inner external gear wheel 74B that make up the gear set 110 are in rotationally symmetric positions shifted by 180° with respect to the swing center 74a.

[0034] Each of the first gear set 110 and the second gear set 112 has the same number of second external gear wheels 74A to 74D that make up the gear set. Also, each of the plurality of second external gear wheels 74A and 74B that make up the first gear set 110 corresponds one-to-one with the individual second external gear wheels 74C and 74D that make up the second gear set 112, and the eccentric phases of the corresponding second external gear wheels 74C and 74D are the same. This pair of second external gear wheels 74A to 74D with the same eccentric phase is called the in-phase gear pair 114A, 114B. In this embodiment, the eccentric phases of the first outer external gear wheel 74A and the second outer external gear wheel 74D are the same, and these are called the first in-phase gear pair 114A. Also, in this embodiment, the eccentric phases of the first inner external gear wheel 74B and the second inner external gear wheel 74C are the same, and these are called the second in-phase gear pair 114B. The condition that the eccentric phases are the same here is handled as satisfying not only the case where the eccentric phases of the two mentioned are exactly the same, but also the case where the eccentric phases of the two are slightly off by a few degrees and are approximately the same.

[0035] The first gear set 110 and the second gear set 112 are such that the arrangement order of the eccentric phases of the external teeth gears 74A and 74B is axially symmetric. The arrangement order of the eccentric phases of the external teeth gears 74A and 74B in the axially outward direction (upward on the paper surface) of the first gear set 110 is the same as the arrangement order of the eccentric phases of the external teeth gears 74C and 74D in the axially outward direction (downward on the paper surface) of the second gear set 112. The eccentric phase of the second external teeth gear 74A or 74B at the M-th position (M is a natural number greater than or equal to 1) in the arrangement order in the axially outward direction of the first gear set 110 is the same as the eccentric phase of the second external teeth gear 74C or 74D at the M-th position in the arrangement order in the axially outward direction of the second gear set 112. For example, in the arrangement order of the eccentric phases of the external teeth gears 74A and 74B in the axially outward direction of the first gear set 110, the eccentric phase of the first inner external teeth gear 74B is 180° and the eccentric phase of the first outer external teeth gear 74A is 0°. At this time, in the arrangement order of the eccentric phases of the external teeth gears 74C and 74D in the axially outward direction of the second gear set 112, the eccentric phase of the second inner external teeth gear 74C is 180° and the eccentric phase of the second outer external teeth gear 74D is 0°. There are two inner external teeth gears 74B and 74C with the same eccentric phase, and two outer external teeth gears 74A and 74D with the same eccentric phase, and the eccentric phases of the inner external teeth gears 74B and 74C and the outer external teeth gears 74A and 74D are shifted by 180°.

[0036] Here, the case where the number of the second external teeth gears 74A to 74D in each gear set 110 and 112 is two has been considered. The number of the second external teeth gears in each gear set 110 and 112 is not particularly limited, and may be three or more. For example, consider the case where the number of the second external teeth gears in each gear set 110 and 112 is three, and the eccentric phases of the respective second external teeth gears are shifted by 120° (= 360° / 3). In this case, the arrangement order of the eccentric phases of the external teeth gears in the axially outward direction (upward on the paper surface) of the first gear set 110 is 0°, 120°, 240°. At this time, the arrangement order of the eccentric phases of the external teeth gears in the axially outward direction (downward on the paper surface) of the second gear set 112 is 0°, 120°, 240°.

[0037] Return to FIG. 6. The speed reduction device 34 includes a first connection mechanism 120 that connects the output carrier 78 and the output shaft 42. The first connection mechanism 120 is connected so as to be able to transmit torque and to allow relative movement in a direction parallel to the plane orthogonal to the axial direction (hereinafter referred to as the axis-orthogonal direction). The first connection mechanism 120 is connected so as to allow displacement in the axis-orthogonal direction of the output carrier 78 and the output shaft 42. The first connection mechanism 120 connects the output carrier 78 and the output shaft 42 by so-called floating connection. The output carrier 78 and the output shaft 42 are relatively movable within a range in which relative movement is allowed by the first connection mechanism 120. As a result, in addition to displacement without rotation in the plane orthogonal to the axial direction between the output carrier 78 and the output shaft 42, displacement is allowed such that the rotation center lines of each other are slightly inclined. Note that the first connection mechanism 120 connects the output carrier 78 and the output shaft 42 so as to allow relative movement in the axial direction as well.

[0038] The first connection mechanism 120 of this embodiment is configured by a spline structure in realizing the floating connection. In addition to this, the first connection mechanism 120 may be configured by a coupling or the like in realizing the floating connection. The first connection mechanism 120 constituting the spline structure includes a first male spline 122 provided on the outer peripheral portion of the output shaft 42 and a first female spline 126 provided in a through hole 124 that axially penetrates the output carrier 78. The first female spline 126 meshes with the first male spline 122. The through hole 124 also serves as the crankshaft hole 96, but may be provided separately from the crankshaft hole 96. A gap (not shown) that allows displacement in the axis-orthogonal direction of the output carrier 78 and the output shaft 42 is provided between the first female spline 126 and the first male spline 122.

[0039] Note that the first male spline 122 may be provided on the output carrier 78 and the first female spline 126 may be provided on the output shaft 42. In other words, the first connection mechanism 120 may include a first male spline 122 provided on one of the output shaft 42 and the output carrier 78 and a first female spline 126 provided on the other of them.

[0040] The effects of the speed reducer 34 described above will be explained. Refer to FIG. 8(A). FIG. 8(A) schematically shows a case where, with respect to the first gear set 110 and the second gear set 112, the axial arrangement order of the eccentric phases of the external gear teeth 74A to 74D is the same. In this case, the second first inner external gear tooth 74B and the fourth second outer external gear tooth 74D from the input side become the in-phase gear pair 114C, and the first first outer external gear tooth 74A and the third second inner external gear tooth 74C from the input side become the in-phase gear pair 114D. In FIG. 8(A), in the plane orthogonal to the axial direction of each of the external gear teeth 74A to 74D, the X direction parallel to the maximum eccentricity direction F1 and the Y direction orthogonal to the axial direction and the X direction are shown.

[0041] During the operation of the speed reducer 34, input loads F2a and F2b are input to the output rotating body 80 from the second external gear teeth 74A to 74D. These input loads F2a and F2b act as the resultant force of the loads acting at the contact points between the second external gear teeth 74A to 74D and the respective inner pins 92. It is known that these input loads F2a and F2b usually act in a certain direction determined according to the maximum eccentricity direction F1 of each of the external gear teeth 74A to 74D, with a certain position determined according to the maximum eccentricity direction F1 of each of the external gear teeth 74A to 74D as the acting point. Here, an example is shown in which the input loads F2a and F2b input from each of the external gear teeth 74A to 74D act in a direction parallel to the maximum eccentricity direction F1 of each of the external gear teeth 74A to 74D at a position shifted by 90° in the rocking direction with respect to the maximum eccentricity direction F1 of each of the external gear teeth 74A to 74D. The rocking direction here refers to the direction in which the gear center C74b rotates around the rocking center C74a (here, the counterclockwise direction). According to the configuration of FIG. 8(A), the phases of the input loads F2a and F2b input from the second external gear teeth 74A to 74D of each in-phase gear pair 114C, 114D to the output rotating body 80 can be made the same. For example, the phases of the input loads F2a input from the first first outer external gear tooth 74A and the second second inner external gear tooth 74C of the in-phase gear pair 114C to the output rotating body 80 can be made the same. Also, the phases of the input loads F2b input from the first second inner external gear tooth 74B and the second second outer external gear tooth 74D of the in-phase gear pair 114D to the output rotating body 80 can be made the same.

[0042] Refer to Fig. 8(B). Fig. 8(B) is a schematic diagram of the input loads F2a and F2b input from the second external gear wheels 74A to 74D of Fig. 8(A) to the output rotating body 80 as viewed from the radial direction. It is assumed that the resultant forces F2a' and F2b' of the input loads F2a and F2b input from the second external gear wheels 74A to 74D of each of the plurality of in-phase gear pairs 114C and 114D to the output rotating body 80 act at the midpoint in the axial direction of the in-phase gear pairs 114C and 114D. The midpoint of these in-phase gear pairs 114C and 114D refers to the midpoint at the center of the tooth width of each of the second external gear wheels 74A to 74D that make up the in-phase gear pairs 114C and 114D. At this time, according to the configurations of Figs. 8(A) and 8(B), the amount of deviation in the axial position of the resultant forces F2a' and F2b' input from the second external gear wheels 74A to 74D of each of the plurality of in-phase gear pairs 114C and 114D to the output rotating body 80 increases. For example, the resultant force F2a' of the input load F2a input from the first outer external gear wheel 74A and the second inner external gear wheel 74C of the in-phase gear pair 114C to the output rotating body 80, and the resultant force F2b' of the input load F2b input from the first inner external gear wheel 74B and the second outer external gear wheel 74D of the in-phase gear pair 114D to the output rotating body 80 are in opposite directions to each other, and the amount of deviation L in their axial positions increases. As a result, due to the deviation in the axial positions of these resultant forces F2a' and F2b', a tipping moment having a magnitude depending on the amount of deviation L in their axial positions acts on the output rotating body 80.

[0043] Refer to Fig. 9(A). Fig. 9(A) shows the same external gear wheels 74A to 74D as those in Fig. 8(A). During the operation of the speed reduction device 34, input loads are input from the eccentric portions 70A to 70D of the second crankshaft 72 to the second external gear wheels 74A to 74D. At the same time, reaction forces F3a and F3b of the input loads are input from the second external gear wheels 74A to 74D to the second crankshaft 72. It is known that these reaction forces F3a and F3b usually act in a direction having a constant angle θ with respect to the maximum eccentricity direction F1 of each external gear wheel 74A to 74D in the rocking direction. According to the configuration of Fig. 9(A), the phases of the reaction forces F3a and F3b input from each of the second external gear wheels 74A to 74D of the plurality of in-phase gear pairs 114C and 114D to the second crankshaft 72 can be adjusted. For example, the phases of the reaction forces F3a input from the first outer external gear wheel 74A and the second inner external gear wheel 74C of the in-phase gear pair 114C can be adjusted. Also, the phases of the reaction forces F3b input from the first inner external gear wheel 74B and the second outer external gear wheel 74D of the in-phase gear pair 114D can be adjusted.

[0044] Refer to Fig. 9(B). Fig. 9(B) is a schematic diagram of the reaction forces F3a and F3b input from the second external gear wheels 74A to 74D of Fig. 9(A) to the second crankshaft 72 as viewed from the radial direction. Here, for the sake of convenience of explanation, only the X-direction components of the reaction forces F3a and F3b are shown. The resultant forces F3a' and F3b' of the reaction forces F3a and F3b input from the plurality of in-phase gear pairs 114C and 114D to the second crankshaft 72 are assumed to act at the midpoint in the axial direction of the in-phase gear pairs 114C and 114D, similar to the resultant forces F2a' and F2b' of the input loads F2a and F2b. At this time, for example, the resultant force F3a' of the reaction forces F3a input from the first outer external gear wheel 74A and the second inner external gear wheel 74C of the in-phase gear pair 114C to the second crankshaft 72 and the resultant force F3b' of the reaction forces F3b input from the first inner external gear wheel 74B and the second outer external gear wheel 74D of the in-phase gear pair 114D to the second crankshaft 72 are in opposite directions to each other, and the displacement amount L of their axial positions becomes large. Therefore, due to the displacement of the axial positions of these resultant forces F3a' and F3b', a tipping moment having a magnitude depending on the displacement amount L of their axial positions acts on the second crankshaft 72.

[0045] Refer to FIG. 10(A). In contrast, for the first gear set 110 and the second gear set 112 of this embodiment, the arrangement order of the eccentric phases of the external gear teeth 74A to 74D is axially symmetric. Therefore, the phases of the input loads F2a and F2b input from the external gear teeth 74A to 74D of each of the plurality of in-phase gear pairs 114A and 114B to the output rotating body 80 can be aligned. At the same time, the axial positions of the resultant forces F2a' and F2b' of the input loads F2a and F2b input from the second external gear teeth 74A to 74D of each of the plurality of in-phase gear pairs 114A and 114B to the output rotating body 80 can be made as uniform as possible.

[0046] (A) For example, according to this embodiment, the phases of the input loads F2a input from the first outer external gear tooth 74A and the second outer external gear tooth 74D of the first in-phase gear pair 114A to the output rotating body 80 can be aligned. Also, the phases of the input loads F2b input from the first inner external gear tooth 74B and the second inner external gear tooth 74C of the second in-phase gear pair 114B to the output rotating body 80 can be aligned. Further, the axial position of the resultant force F2a' of the input loads F2a input from the external gear teeth 74A and 74D acting on the midpoint of the first in-phase gear pair 114A to the output rotating body 80 and the axial position of the resultant force F2b' of the input loads F2b input from the external gear teeth 74B and 74C acting on the midpoint of the second in-phase gear pair 114B to the output rotating body 80 can be made as uniform as possible. That is, as shown in FIG. 8(A), compared with the case where the arrangement order of the eccentric phases of each gear set 110 and 112 is the same, the deviation amount L of the axial positions of the resultant forces F2a' and F2b' of the input loads F2a and F2b input from each of the in-phase gear pairs 114A and 114B to the output rotating body 80 can be reduced. Here, an example where this deviation amount L becomes zero is shown. It can be said that the midpoints of each of the in-phase gear pairs 114A and 114B are provided at coincident axial positions. Thereby, the overturning moment acting on the output rotating body 80 due to the deviation of the axial positions of the resultant forces F2a' and F2b' of the input loads F2a and F2b input from each of the in-phase gear pairs 114A and 114B to the output rotating body 80 can be suppressed as much as possible. Therefore, the required load capacity of the main bearing 94 that supports the output rotating body 80 can be reduced, which is advantageous for reducing the outer diameter of the main bearing 94.

[0047] Refer to FIG. 10(B). Also, according to the above-described configuration, the amount of deviation L in the axial position of the resultant forces F3a' and F3b regarding the reaction forces F3a and F3b input from each of the in-phase gear pairs 114A and 114B to the second crankshaft 72 can also be reduced. For example, the resultant force F3a' of the reaction force F3a is input to the second crankshaft 72 from the first outer external gear 74A and the second outer external gear 74D of the first in-phase gear pair 114A, and the resultant force F3b' of the reaction force F3b of the first inner external gear 74B and the second inner external gear 74C of the second in-phase gear pair 14B is input. According to the above-described configuration, as shown in FIG. 8(B), compared with the case where the arrangement order of the eccentric phases of each gear set 110 and 112 is the same, the amount of deviation L in the axial position of the resultant forces F3a' and F3b input from each of the in-phase gear pairs 114A and 114B to the second crankshaft 72 can be reduced. Here, an example where the amount of deviation L becomes zero is shown. Thereby, the overturning moment acting on the second crankshaft 72 due to the deviation in the axial position of the resultant forces F3a' and F3b of the reaction forces F3a and F3b input from each of the in-phase gear pairs 114A and 114B to the second crankshaft 72 can be suppressed as much as possible. Thereby, the required load capacity of the crankshaft bearing 84 that supports the second crankshaft 72 can be reduced, which is advantageous for reducing the outer diameter of the crankshaft bearing 84 and is advantageous for reducing the outer diameter of the speed reduction device 34.

[0048] (B) The output carrier 78 and the output shaft 42 are connected by a first connection mechanism 120 so as to allow relative movement in the direction orthogonal to the axis. Therefore, when a radial external load is input to the output shaft 42 as an impact load, the output shaft 42 is displaced in the direction orthogonal to the axis within a range where it can relatively move with respect to the output carrier 78, making it difficult for the radial external load to be transmitted from the output shaft 42 to the output carrier 78. Also, at least a part of the external load input to the output shaft 42 can be diverted to the output shaft bearings 44A and 44B without being transmitted to the output carrier 78. As a result, compared to the case where the output carrier 78 and the output shaft 42 are connected so as not to be relatively movable in the direction orthogonal to the axis, the radial external load transmitted to the output carrier 78 can be reduced. Consequently, the required load capacity of the main bearing 94 that supports the output rotating body 80 including the output carrier 78 can be reduced, which is advantageous for reducing the outer diameter of the main bearing 94.

[0049] Combined with the above (A) and (B), the required load capacity of the main bearing 94 that supports the output rotating body 80 can be significantly reduced, which is greatly advantageous for reducing the outer diameter of the main bearing 94. This is advantageous for reducing the outer diameter of the speed reduction device 34. In particular, when the speed reduction device 34 is used in a yaw drive device, a very large radial external load is input to the output shaft 42 as an impact load due to gusts, typhoons, etc. If this is supported by the main bearing 94, the main bearing 94 tends to become very large. Even in such a case, it is particularly effective in terms of being advantageous for reducing the size of the main bearing 94.

[0050] Also, by using an eccentric swing type speed reduction mechanism having a plurality of second external gear wheels 74A to 74D, it is advantageous for reducing the axial dimension of the speed reduction device 34 in obtaining a large reduction ratio compared to the case of using a simple planetary type speed reduction mechanism. Further, in this eccentric swing type speed reduction mechanism, a trochoid tooth profile is used for the second external gear wheels 74A to 74D. Therefore, compared to a simple planetary type speed reduction mechanism using a gear pair with an involute tooth profile, there is also an advantage that tooth breakage due to impact torque caused by an external load is less likely to occur. That is, it is possible to increase the strength against impact torque while being advantageous for reducing the axial dimension and the outer diameter of the speed reduction device 34 in obtaining a large reduction ratio.

[0051] Also, as described above, since the tipping moment acting on the output rotating body 80 can be suppressed, there is also an advantage that it is not necessary to provide the output shaft bearings 44A and 44B with a function of supporting the tipping moment.

[0052] In the case of the distribution type eccentric swing type speed reduction mechanism in which the second crankshaft 72 is provided at a position offset from the swing center C74a, usually, it is necessary to transmit rotation from the rotating shaft provided on the swing center C74a to the second crankshaft 72. For this reason, usually, after providing a center pinion that can rotate integrally with the rotating shaft on the swing center C74a, a crankshaft gear that meshes with the center pinion is provided on the second crankshaft 72. In this case, a moment load is generated on the second crankshaft 72 due to the meshing between the center pinion and the crankshaft gear, and the required load capacity of the crankshaft bearing 84 that supports the moment load increases.

[0053] In this regard, in the present embodiment, the second crankshaft 72 is provided on the swing center C74a of the second external gear 74A to 74D, and the second speed reduction mechanism 40 including the second crankshaft 72 constitutes a center crank type eccentric swing type speed reduction mechanism. Therefore, when transmitting rotation from the rotating shaft provided on the swing center C74a (the intermediate output shaft 60 in the embodiment) to the second crankshaft 72, it is not necessary to provide a center pinion and a crankshaft gear. For this reason, a moment load caused by meshing such as a crankshaft gear does not occur on the second crankshaft 72. Therefore, the required load capacity of the crankshaft bearing 84 can be further reduced, which is more advantageous for miniaturization of the crankshaft bearing 84.

[0054] The first connection mechanism 120 is configured by a spline structure including a first male spline 122 and a first female spline 126. Therefore, it is advantageous for reducing the outer diameter around the first connection mechanism 120 as compared with the case where the first connection mechanism 120 is configured by a coupling.

[0055] When arranging a plurality of drive devices 24 in the circumferential direction around the rotation center line C14 of the nacelle 14, in view of the relationship between the increase in the number of drive devices 24 and the workability during installation, it is required to reduce the outer diameter of the speed reduction device 34 used in the drive device 24. Since the speed reduction device 34 described above is advantageous for reducing the outer diameter, it is suitable for use in a wind turbine 10 that requires such a reduction in the outer diameter.

[0056] When using the drive device 24 as a yaw drive device housed in the nacelle 14, in order to avoid interference with the speed increaser and the generator in the nacelle 14, it is also required to reduce the axial dimension of the speed reduction device 34 used in the drive device 24. Since the eccentric swing type reduction mechanism is used in the speed reduction device 34 of this embodiment, the axial dimension can be reduced to obtain a large reduction ratio compared to the case of using a simple planetary reduction mechanism. For example, the speed reduction device 34 used in the yaw drive device often requires a large reduction ratio of 1000 or more. If this is realized by a simple planetary speed reduction device, it is often realized by a simple planetary reduction mechanism with four or more stages, which leads to an increase in the axial dimension. In this regard, when using an eccentric swing type reduction mechanism, a reduction ratio of 1000 or more can be realized by an eccentric swing type reduction mechanism with two or more stages, and the axial dimension can be significantly reduced. Therefore, the speed reduction device 34 of this embodiment is suitable for a yaw drive device that requires a large reduction ratio and a reduction in the axial dimension.

[0057] Next, other features of the speed reducer 34 of this embodiment will be described. Referring to FIG. 7, the speed reducer 34 includes a second connection mechanism 130 that connects the second crankshaft 72 and the intermediate output shaft 60. The second connection mechanism 130 connects the second crankshaft 72 and the intermediate output shaft 60 so as to be capable of transmitting torque and allowing relative movement in the direction orthogonal to the axes. The second connection mechanism 130 will connect the second crankshaft 72 and the intermediate output shaft 60 so as to allow misalignment in the direction orthogonal to the axes. Similar to the first connection mechanism 120, the second connection mechanism 130 will connect the second crankshaft 72 and the intermediate output shaft 60 by a so-called floating connection. The second crankshaft 72 and the intermediate output shaft 60 are capable of relative movement within the range allowed by the second connection mechanism 130. Thereby, in addition to misalignment without rotation in the plane orthogonal to the axial direction of the second crankshaft 72 and the intermediate output shaft 60, misalignment such that the rotation center lines of each other are slightly inclined is allowed. Note that the second connection mechanism 130 connects the second crankshaft 72 and the intermediate output shaft 60 so as to also allow relative movement in the axial direction.

[0058] The second connection mechanism 130 of this embodiment is configured by a spline structure in realizing a floating connection. In addition to this, the second connection mechanism 130 may be configured by a coupling or the like in realizing a floating connection. The second connection mechanism 130 configuring the spline structure includes a second male spline 132 provided on the outer peripheral portion of the second crankshaft 72 and a second female spline 136 provided in a through hole 134 that axially penetrates the intermediate output shaft 60. The second female spline 136 meshes with the second male spline 132. A gap (not shown) that allows misalignment in the direction orthogonal to the axes of the second crankshaft 72 and the intermediate output shaft 60 is provided between the second female spline 136 and the second male spline 132.

[0059] Since the output carrier 78 is allowed to move relative to the output shaft 42 in the direction orthogonal to the axis by the first connection mechanism 120, displacement in the direction orthogonal to the axis of the output rotating body 80 can occur. The displacement in the direction orthogonal to the axis of the output rotating body 80 is transmitted to the second crankshaft 72 via the second inner pin 92, the second external gear 74A to 74D, and the eccentric bearing 86, or is transmitted to the second crankshaft 72 via the crankshaft bearing 84, and displacement in the direction orthogonal to the axis can also occur in the second crankshaft 72. When the second crankshaft 72 is displaced in the direction orthogonal to the axis in this way, the second connection mechanism 130 allows the second crankshaft 72 to move relative to the intermediate output shaft 60 in the direction orthogonal to the axis within the range where the second crankshaft 72 can move relative to the intermediate output shaft 60, making it difficult for the displacement to be transmitted from the second crankshaft 72 to the intermediate output shaft 60. As a result, compared with the case where the second crankshaft 72 and the intermediate output shaft 60 are connected so as not to be relatively movable, the load transmitted to the intermediate output shaft 60 due to the displacement can be reduced. Consequently, the required load capacity of the bearings 140A and 140B that support the intermediate output shaft 60 can be reduced, which is advantageous for miniaturizing the bearings 140A and 140B.

[0060] In relation to such an effect, the second connection mechanism 130 only needs to connect the rotating shaft that inputs rotation to the second crankshaft 72 and the second crankshaft 72. This rotating shaft has been exemplified by the intermediate output shaft 60 of the first reduction mechanism 38, but it may also be the motor shaft 30. Further, the second connection mechanism 130 having a spline structure only needs to include a second male spline 132 provided on one of the second crankshaft 72 and the rotating shaft, and a second female spline 136 provided on the other of them and meshing with the second male spline 132.

[0061] Next, the features regarding the main bearing 94 will be described. As described above, since the required load capacity of the main bearing 94 that supports the output rotating body 80 is reduced, the reduction device 34 does not necessarily need to include the main bearing 94. In addition to this, since the required load capacity is reduced, a main bearing 94 with a small outer diameter may be used only for positioning without supporting the load. In order to reduce the outer diameter of the main bearing 94 in this way, the following configuration may be adopted.

[0062] When viewed axially, the entire main bearing 94 is arranged radially inward of the center lines C90 and C92 of the pins 90 and 92. This condition only needs to be satisfied in relation to either the carrier pin 90 or the second inner pin 92. Thereby, when viewed axially, compared with the case where at least a part of the main bearing 94 is arranged radially outward from the center lines C90 and C92 of the pins 90 and 92, the outer diameter of the main bearing 94 can be reduced. From such a viewpoint, it is preferable that the entire main bearing 94 is arranged radially inward of the entire pins 90 and 92. This condition also only needs to be satisfied in relation to either the carrier pin 90 or the second inner pin 92.

[0063] The input-side carrier 88 of the output rotating body 80 includes a carrier-side arrangement surface 150 on which the main bearing 94 is arranged, and the casing 46 includes a casing-side arrangement surface 152 on which the main bearing 94 is arranged. The carrier-side arrangement surface 150 of the present embodiment is provided on the input-side carrier 88, but may be provided on the output-side carrier 78. The carrier-side arrangement surface 150 of the present embodiment is arranged radially outward of the rolling elements of the main bearing 94, and the casing-side arrangement surface 152 is arranged radially inward of the rolling elements. Thereby, compared with the case where the carrier-side arrangement surface 150 is arranged radially inward of the rolling elements, it is advantageous for reducing the outer diameter of the main bearing 94.

[0064] Note that the speed reduction device 34 of the present embodiment includes only a single main bearing 94 arranged between the casing 46 and the output rotating body 80. As the single main bearing 94, in addition to the ball bearing as in the present embodiment, various bearings such as a cross roller bearing may be adopted. In addition, a plurality of main bearings 94 may be arranged between the casing 46 and the output rotating body 80.

[0065] As described above, since the required load capacity of the crankshaft bearing 84 that supports the second crankshaft 72 is also reduced, the speed reducer 34 may not include the crankshaft bearing 84. In addition to this, since the required load capacity is reduced, a crankshaft bearing 84 with a small outer diameter may be used only for positioning without supporting the load. Further, when reducing the outer diameter of the crankshaft bearing 84 in this way, the outer diameter of the crankshaft bearing 84 may be smaller than the outer diameters of the bearings 140A and 140B that support the intermediate output shaft 60. These bearings 140A and 140B include a first bearing 140A arranged on the input side and a second bearing 140B arranged on the output side in this embodiment. In this embodiment, the outer diameter of the second bearing 140B is smaller than the outer diameter of the first bearing 140A. In order to make the outer diameter of the crankshaft bearing 84 smaller than the outer diameters of the bearings 140A and 140B, it is sufficient that the outer diameter of the crankshaft bearing 84 is smaller than the outer diameter of either the first or second bearing 140A and 140B. In addition to this, from the same viewpoint, the crankshaft bearing 84 may be constituted by a thrust bearing that receives a thrust load without receiving a radial load. Note that each of the output shaft bearings 44A and 44B, the crankshaft bearing 84, the main bearing 94, and the bearings 140A and 140B of this embodiment is constituted by a radial bearing that receives a radial load.

[0066] Next, the features regarding the eccentric portions 70A to 70D will be described. The plurality of eccentric portions 70A to 70D of the second crankshaft 72 include a first eccentric portion 70A that is on the most axially input side, a second eccentric portion 70B that is adjacent to the first eccentric portion 70A on the output side, a third eccentric portion 70C that is adjacent to the second eccentric portion 70B on the output side, and a fourth eccentric portion 70D that is on the most axially output side. The plurality of eccentric portions 70A to 70D are provided corresponding to each of the plurality of second external gear wheels 74A to 74D. Each of the plurality of eccentric portions 70A to 70D has the same eccentric phase as the eccentric phase of the corresponding second external gear wheel 74A to 74D. Each of the eccentric portions 70A to 70D exhibits a circular cross-sectional shape with the same diameter centered on the axis C70. The radial length from the rotation center line C72 of the second crankshaft 72 to the axis C70 of each of the eccentric portions 70A to 70D is referred to as the eccentricity of each of the eccentric portions 70A to 70D. At this time, the eccentricities of each of the eccentric portions 70A to 70D are the same. Similar to the plurality of second external gear wheels 74A to 74D, the plurality of eccentric portions 70A to 70D also include the second and third eccentric portions 70B and 70C that are on the two axially inner sides with the same eccentric phase, and the first and fourth eccentric portions 70A and 70D that are on the two axially outer sides with the same eccentric phase. The eccentric phases of the second and third eccentric portions 70B and 70C and the first and fourth eccentric portions 70A and 70D are shifted by 180°.

[0067] The second crankshaft 72 includes a shaft member 160 and a cylindrical member 162 that is fitted to the outer peripheral portion of the shaft member 160. The shaft member 160 constitutes a range from the tip end side end portion to the base end side end portion of the second crankshaft 72. The cylindrical member 162 is provided separately from the shaft member 160 and the eccentric bearing 86. In order to satisfy the condition that "the cylindrical member 162 and the eccentric bearing 86 are provided separately" here, when the second crankshaft 72 also serves as the inner ring 86b of the eccentric bearing 86, it is sufficient that the rolling elements 86a of the eccentric bearing 86 are provided separately from the cylindrical member 162. On the contrary, when the inner ring 86b and the second crankshaft 72 are provided separately, it is sufficient that the inner ring 86b is provided separately from the cylindrical member 162.

[0068] In this embodiment, the input-side shaft portion 82A, the output-side shaft portion 82B, and the second to fourth eccentric portions 70D are constituted by a shaft member 160, and the first eccentric portion 70A is constituted by the shaft member 160 and a cylindrical member 162. The shaft member 160 includes an inner fitting portion 164 into which the cylindrical member 162 is fitted on the outer peripheral portion. The cylindrical member 162 is fitted into the inner fitting portion 164 of the shaft member 160 by an interference fit. The inner fitting portion 164 of this embodiment has a circular cross-sectional shape centered on an axis C164 eccentric with respect to the rotation center line C72 of the second crankshaft 72, and its eccentric phase matches the eccentric phase of the first eccentric portion 70A. Also, the radial length from the rotation center line C72 to the axis C164 of the inner fitting portion 164 matches the eccentric amount of the first eccentric portion 70A. The cylindrical member 162 includes a through hole in which the inner fitting portion 164 of the shaft member 160 is disposed inside. The cylindrical member 162 has a concentric cylindrical shape in which the hole center of the through hole and the outer shape center of the cylindrical member 162 are concentric. Here, the outer shape center of the cylindrical member 162 refers to the center of the outer peripheral surface of the cylindrical member 162 as viewed from the axial direction. Thus, the first eccentric portion 70A is constituted by the shaft member 160 and the cylindrical member 162.

[0069] In addition to this, an eccentric collar having an eccentric cylindrical shape may be used as the cylindrical member 162. Here, the eccentric cylindrical shape means that the cylindrical member 162 has a cylindrical shape in which the hole center is eccentric with respect to the outer shape center. In this case, the inner fitting portion 164 of the shaft member 160 is made to have a circular cross-sectional shape centered on the rotation center line C72 of the second crankshaft 72. The phase around the hole center in the direction from the hole center to the outer shape center of the cylindrical member 162 is defined as the eccentric phase of the cylindrical member 162. At this time, the eccentric phase of the eccentric cylindrical-shaped cylindrical member 162 matches the eccentric phase of the first eccentric portion 70A. Also, the radial length from the hole center to the outer shape center of the cylindrical member 162 matches the eccentric amount of the first eccentric portion 70A. Thus, the first eccentric portion 70A is constituted by the shaft member 160 and the cylindrical member 162.

[0070] By configuring the first eccentric portion 70A with the cylindrical member 162 in this way, compared with the case where the first eccentric portion 70A is configured with the shaft member 160, the step 166 formed between the portion of the shaft member 160 that overlaps the first eccentric portion 70A in the radial direction and the input-side shaft portion 82A can be reduced. As a result, the stress concentration around the step 166 of the shaft member 160 can be reduced, which is advantageous for ensuring the durability of the second crankshaft 72.

[0071] In the axial range R1 from the first eccentric portion 70A to the input-side end portion 160a, the shaft member 160 does not overlap with the outer peripheral surface of the second eccentric portion 70B when viewed from the axial direction. The shaft member 160 is provided at a position that fits inside the outer peripheral surface of the second eccentric portion 70B when viewed from the axial direction within this axial range R1. Thereby, when arranging the second external gear 74B corresponding to the second eccentric portion 70B via the eccentric bearing 86 on the outer peripheral portion of the second eccentric portion 70B, it is not necessary to interfere with the eccentric bearing 86 and the second external gear 74B. Further, in this embodiment, since the eccentric phases of the second eccentric portion 70B and the third eccentric portion 70C are the same, when arranging the second external gear 74C corresponding to the third eccentric portion 70C via the eccentric bearing 86 on the outer peripheral portion of the third eccentric portion 70C, it is not necessary to interfere with the eccentric bearing 86 and the second external gear 74C.

[0072] These eccentric bearings 86, the second external gears 74B and 74C, and the eccentric bearing 86 and the second external gear 74A arranged on the outer peripheral portion of the first eccentric portion 70A are arranged on the outer peripheral portions of the respective eccentric portions 70A to 70C by moving them from the input side to the output side with respect to the shaft member 160. Further, when arranging the second external gear 74D corresponding to the fourth eccentric portion 70D via the eccentric bearing 86 on the outer peripheral portion of the fourth eccentric portion 70D, the eccentric bearing 86 and the second external gear 74D are moved from the output side to the input side with respect to the shaft member 160.

[0073] By adopting such a configuration, in the axial range R1 from the second eccentric portion 70B to the input-side end portion 160a, the shaft member 160 can be shaped so as not to increase in diameter toward the input side. In this axial range R1, the shaft member 160 can be shaped by combining a portion having the same outer diameter toward the input side and a portion having a reduced diameter toward the input side. As a result, in this axial range R1, a shape without a large step can be achieved, and by reducing the stress concentration of the shaft member 160, it is advantageous for ensuring the durability of the second crankshaft 72.

[0074] Next, features regarding the carrier pin 90 and the second inner pin 92 will be described. In connecting the respective carriers 78 and 84 in cooperation with the bolt 98, the carrier pin 90 of this embodiment also serves as the shaft portion 98a of the bolt 98. The bolt 98 includes a shaft portion 98a and a head portion 98b provided at the base end portion of the shaft portion 98a. The head portion 98b of this embodiment is provided separately from the shaft portion 98a, but may be integrally provided by the same member as the shaft portion 98a. A nut constituting the head portion 98b of the bolt 98 is screwed onto the base end portion of the shaft portion 98a that is separate from the head portion 98b.

[0075] The bolt 98 that the carrier pin 90 also serves as connects the output-side carrier 78 and the input-side carrier 88 by clamping them together. To achieve this, the shaft portion 98a of the bolt 98 of this embodiment is provided at its tip-side portion and includes a male screw portion 98c that is screwed into a female screw hole of the output-side carrier 78. The head portion 98b of the bolt 98 is seated on the axially outer surface of the input-side carrier 88 via a washer 170. A spacer 172 is disposed between the output-side carrier 78 and the input-side carrier 88 around the center line C90 of the carrier pin 90. The spacer 172 maintains the interval between the respective carriers 78 and 88. The spacer 172 of this embodiment is integrally provided with the carrier pin 90 by the same member as the carrier pin 90 and is constituted by a shoulder portion having a larger diameter than other portions adjacent to the carrier pin 90 in the axial direction. In addition to this, the spacer 172 may be constituted by a cylindrical member through which the carrier pin 90 is inserted.

[0076] The second inner pin 92 is fitted into a first pin hole 174 provided in the output-side carrier 78 and also fitted into a second pin hole 176 provided in the input-side carrier 88. The second inner pin 92 is fitted into the first and second pin holes 174, 176 by interference fit. The first pin hole 174, which is on the opposite side of the washer 170 in the axial direction with respect to the second inner pin 92, has a bottom portion 174a. The second inner pin 92 is restricted from being pushed in by hitting the bottom portion 174a of the first pin hole 174. The second pin hole 176, which is on the washer 170 side in the axial direction with respect to the second inner pin 92, has an opening 178 that opens on the axially outer surface 80a of the output rotating body 80 on the washer 170 side in the axial direction. The second inner pin 92 is, for example, inserted into the first pin hole 174 of the output-side carrier 78 from the input side, and then inserted into the second pin hole 176 of the input-side carrier 88 from the output side by relative movement of the input-side carrier 88 and the second inner pin 92, so as to be fitted into each of the pin holes 174, 176.

[0077] The speed reduction device 34 includes the aforementioned washer 170 disposed between the head 98b of the bolt 98 and the axially outer surface 80a of the output rotating body 80. Here, the "axially outer surface 80a of the output rotating body 80" refers to the axially outer surface of the input-side carrier 88 in this embodiment. The washer 170 is disposed at a position overlapping the opening 178 side with respect to the second pin hole 176 when viewed from the axial direction. Thereby, when the second inner pin 92 tries to come out from the second pin hole 176 toward the opening 178 side, the washer 170 can restrict the second inner pin 92 from coming out toward the opening 178 side of the second pin hole 176 by hitting the second inner pin 92. The washer 170 satisfies the same conditions in relation to the second inner pins 92 fitted into each of the plurality of pin holes 174, 176, and can restrict the coming out of each second inner pin 92. The washer 170 having such conditions forms an annular shape surrounding the swing center C74a and has a plurality of bolt holes 180 through which the shaft portions 98a of the individual bolts 98 are inserted at intervals in the circumferential direction.

[0078] As a result, a retaining member for restricting the removal of the second inner pin 92 can be also used as the washer 170, and the number of components can be reduced as compared with the case where the retaining member and the washer 170 are separate bodies. Further, a design that reduces the tightening allowance of the second inner pin 92 with respect to each pin hole 174, 176 is allowed, which is advantageous for improving the assemblability of the second inner pin 92.

[0079] From the viewpoint of obtaining such an effect, the head 98b of the bolt 98 may be seated on the axially outer surface of the output carrier 78 via the washer 170 as the axially outer surface 80a of the output rotating body 80. In this case, it is sufficient that the first pin hole 174 is provided with an opening 178 that opens to the axially outer surface of the output carrier 78, and it is sufficient that the removal of the second inner pin 92 from the opening 178 side with respect to the first pin hole 174 can be restricted by the washer 170.

[0080] In the above example, the case where the output carrier 78 and the input carrier 88 are tightened together by the bolt 98 that also serves as the carrier pin 90 when the carrier pins 90 connect the carriers 78, 88 in cooperation with the bolt 98 has been described. In addition to this, from the viewpoint of obtaining the above-described effect, the output carrier 78 and one of the input carrier 88 and the carrier pin 90 may be tightened together by a bolt 98 that is separate from the carrier pin 90. In this case, the carrier pin 90 may protrude from the other of the output carrier 78 and the input carrier 88.

[0081] Refer to FIGS. 5 and 6. Inside the casing 46 of the speed reduction device 34, enclosed spaces 190 and 192 for enclosing a lubricant are formed. The enclosed spaces 190 and 192 include a first enclosed space 190 in which at least the meshing portions of the first external gear 54 and the first internal gear 56 of the first speed reduction mechanism 38 are arranged inside, and a second enclosed space 192 in which at least the meshing portions of the second external gears 74A to 74D and the second internal gear 76 of the second speed reduction mechanism 40 are arranged inside. The first enclosed space 190 is sealed by a plurality of first sealing members 194A and 194B, and the second enclosed space 192 is sealed by a plurality of second sealing members 196A and 196B. The plurality of first sealing members 194A and 194B include an input-side first sealing member 194A arranged between the casing 46 and the first crankshaft 52, and an output-side first sealing member 194B arranged between the casing 46 and the intermediate output shaft 60. The plurality of second sealing members 196A and 196B include an input-side second sealing member 196A that also serves as the output-side first sealing member 194B, and an output-side second sealing member 196B arranged between the casing 46 and the output shaft 42. The output-side second sealing member 196B of the present embodiment is in contact with a positioning member 232 (described later) arranged on the outer peripheral portion of the output shaft 42 and the casing 46 between the casing 46 and the output shaft 42. Each of the sealing members 194A, 194B, 196A, and 196B is constituted by an oil seal or the like.

[0082] When a simple planetary speed reduction mechanism is used, it is known that the involute teeth mesh with each other in a convex-convex manner, which is disadvantageous for lubrication. Against such a background, when a simple planetary speed reduction mechanism is used, usually, as the lubricant, a lubricating oil that is more advantageous in lubricity than grease is used. In particular, in the first enclosed space 190 where the gear meshing portions of the first speed reduction mechanism 38 that rotate at high speed are arranged inside, lubricating oil that is more advantageous for high-speed rotation than grease is often used.

[0083] On the other hand, when an eccentric swing type reduction mechanism such as the first and second reduction mechanisms 38 and 40 is used, it is known that an uneven meshing using a trochoid tooth profile of an external gear is advantageous for lubrication. In this embodiment, an uneven meshing occurs between each external gear 54, 74A to 74D using a trochoid tooth profile and an internal gear 56, 76 using an arc tooth profile. In this embodiment, as the first and second reduction mechanisms 38 and 40, such an eccentric swing type reduction mechanism advantageous for lubrication is used. Therefore, even if grease with a high consistency number is used as a lubricant instead of a general lubricating oil in a simple planetary type reduction mechanism, the required lubricity can be ensured. In this embodiment, grease with a consistency number of 2 or more is used as the lubricant enclosed in each of the first and second enclosed spaces 190 and 192. The consistency number here refers to a number classified according to the range of the mixed consistency of grease defined in JIS K2220. Thereby, it is possible to make it difficult for the internal pressure in each of the enclosed spaces 190 and 192 to rise as compared with the case of using lubricating oil as the lubricant. Further, when grease with a high consistency number is adopted, there is an advantage that oil separation is difficult and it is less likely to leak to the outside as compared with the case of using lubricating oil.

[0084] Refer to FIG. 6. The second enclosed space 192 includes a gear housing space 200 that houses the second external gears 74A to 74D. The first connection mechanism 120 is provided at a position where it can contact the lubricant in the second enclosed space 192. The first connection mechanism 120 is provided at a position where the lubricant can contact while being enclosed in the second enclosed space 192 without leaking to the outside from the sealing portions of the second sealing members 196A and 196B. On the premise of satisfying this condition, when the output shaft 42 and the output-side carrier 78 connected by the first connection mechanism 120 relatively move in the direction perpendicular to the axis, the contacting portions with each other may be provided at positions where the lubricant in the second enclosed space 192 can flow. The "contacting portions with each other" here refers to the first male spline 122 and the first female spline 126 of the first connection mechanism 120 in this embodiment.

[0085] In order to achieve this, the output-side carrier 78 is provided with the above-described through-hole 124 that communicates with the gear accommodation space 200. The through-hole 124 communicates with the gear accommodation space 200 on the side of the second external gear 74A to 74D in its axial direction. The first connection mechanism 120 is disposed in the through-hole 124 on the side opposite to the second external gear 74A to 74D in its axial direction. Thereby, the lubricant in the gear accommodation space 200 can flow to the first connection mechanism 120 in the through-hole 124 via the through-hole 124, and the lubricant can come into contact with the first connection mechanism 120. It should be noted that no sealing member such as a seal cap that restricts the flow of the lubricant from the gear accommodation space 200 toward the first connection mechanism 120 is attached to the through-hole 124.

[0086] The meshing portions of the second external gears 74A to 74D and the second internal gear 76 are lubricated by the lubricant enclosed in the gear accommodation space 200 of the second enclosed space 192. According to the above-described configuration, the first connection mechanism 120 can also be lubricated using the lubricant in the gear accommodation space 200. In particular, the first connection mechanism 120 allows relative movement in the direction perpendicular to the axis of the output shaft 42 and the output-side carrier 78, and may be worn due to the relative movement, but it is advantageous in that the wear can be suppressed by the lubricant.

[0087] Also, the first connection mechanism 120 is disposed in the through-hole 124 of the output-side carrier 78 that communicates with the gear accommodation space 200. Therefore, as described above, the lubricant in the gear accommodation space 200 can naturally come into contact with the first connection mechanism 120 by flowing. Thereby, the first connection mechanism 120 can be easily lubricated using the lubricant in the gear accommodation space 200.

[0088] Referring to FIG. 4, the casing 46 includes a flange portion 46a for detachably attaching to the external member 203 by the mounting bolts 202. The flange portion 46a is attached to the external member 203 by the mounting bolts 202 that clamp the flange portion 46a and the external member 203 together. The external member 203 of the present embodiment is provided as a part of the nacelle 14.

[0089] The casing 46 is provided with an injection hole 204 for injecting lubricant into the second enclosed space 192 and a discharge hole 206 for discharging the lubricant in the second enclosed space 192. Each of the injection hole 204 and the discharge hole 206 can be closed by an individual plug member 208. The plug member 208 is detachable from each of the injection hole 204 and the discharge hole 206.

[0090] The discharge hole 206 is provided at a position that does not overlap with the mounting bolts 202 used for the flange portion 46a of the casing 46 when viewed in the radial direction and at a position that overlaps with the output side carrier 78. By providing the discharge hole 206 at a position that does not overlap with the mounting bolts 202 in this way, when discharging the lubricant to the outside through the discharge hole 206, there is no interference with the mounting bolts 202, and the workability is good. Also, since the grease below the output side carrier 78 hardly flows in the second enclosed space 192, that grease does not need to be replaced. Therefore, there is no particular problem even if the discharge hole 206 is provided at a position that overlaps with the output side carrier 78 and the grease below the output side carrier 78 is not replaced.

[0091] Refer to FIG. 11. In this figure, hatching is applied only to the high hardness regions 234 and 238 described later. The speed reduction device 34 includes a lubricant reservoir 220 formed between the output shaft bearing 44A and the output side second sealing member 196B. The lubricant reservoir 220 is constituted by a recess formed in the inner peripheral portion of the casing 46. This recess is formed so as to extend radially outside the outer arrangement surface 222 where the output side second sealing member 196B of the casing 46 is arranged. In addition to this, the lubricant reservoir 220 may be constituted by a recess formed in the outer peripheral portion of the output shaft 42. The lubricant reservoir 220 serves to store the lubricant that leaks out through the casing 46 and between the output shaft 42 and the output side second sealing member 196B. As a result, the output shaft bearing 44A can be lubricated using the lubricant stored in the lubricant reservoir 220, and it is possible to dispense with replenishing the lubricant for the output shaft bearing 44A for a long time.

[0092] The output shaft 42 is provided with a bearing restricting portion 230 provided on the output side with respect to the output shaft bearing 44A. The bearing restricting portion 230 of the present embodiment is a stepped portion provided on the output shaft 42, but it may also be a retaining ring or the like provided on the output shaft 42. The bearing restricting portion 230 restricts the movement of the output shaft bearing 44A to the output side by hitting it from the output side with respect to the output shaft bearing 44A.

[0093] The speed reduction device 34 includes a positioning member 232 disposed between the output shaft bearing 44A and the output side carrier 78. The positioning member 232 abuts on the inner ring of the output shaft bearing 44A from the input side and restricts the movement thereof to the input side, thereby positioning the axial positions of the output shaft bearings 44A and 44B with respect to the output shaft 42. The positioning member 232 of the present embodiment is constituted by a cylindrical member disposed on the outer peripheral side of the output shaft bearings 44A and 44B. The output side carrier 78 and the positioning member 232 are made of, for example, a metal material such as steel.

[0094] The output side carrier 78 is provided with a first high hardness region 234 on the contact surface with respect to the positioning member 232. The first high hardness region 234 has a higher surface hardness than the first low hardness region 236 provided at other locations on the output side carrier 78. Here, other locations refer to locations on the output side carrier 78 that do not contact other members, for example, the outer peripheral surface of the output side carrier 78, and the first low hardness region 236 is provided there. The first high hardness region 234 is constituted by a surface hardened region that is harder than its base material region by surface hardening treatment on the base material region. The first low hardness region 236 is constituted by its base material region. The surface hardening treatment is, for example, surface heat treatment such as partial quenching using a laser or the like.

[0095] The positioning member 232 is provided with a second high-hardness region 238 on the contact surface with respect to the output-side carrier 78. The second high-hardness region 238 has a higher surface hardness than a second low-hardness region 240 provided at other locations of the positioning member 232. Here, other locations refer to locations where the positioning member 232 does not contact other members. For example, it is the outer peripheral surface of the positioning member 232, and the second low-hardness region 240 is provided there. The second high-hardness region 238 is constituted by a surface-hardened region that has a higher hardness than its base material region through a surface hardening treatment on the base material region. The second low-hardness region 240 is constituted by its base material region. The surface hardening treatment is, for example, a surface heat treatment such as partial quenching using a laser or the like.

[0096] The output-side carrier 78 is allowed to move relatively in the direction perpendicular to the axis with respect to the output shaft 42 by the first connection mechanism 120. Therefore, fretting wear is likely to occur on the contact surfaces of the output-side carrier 78 and the positioning member 232 due to the relative movement of the output-side carrier 78 with respect to the output shaft 42. As a countermeasure, high-hardness regions 234 and 238 are provided on the contact surfaces of the output-side carrier 78 and the positioning member 232. Thereby, compared with the case where the surface hardness of those contact surfaces is made the same as that of the low-hardness regions 236 and 240, fretting wear on the contact surfaces of the output-side carrier 78 and the positioning member 232 caused by the relative movement of the output-side carrier 78 with respect to the output shaft 42 can be suppressed.

[0097] In relation to such an effect, it is sufficient that at least one of the output-side carrier 78 and the positioning member 232 is provided with high-hardness regions 234 and 238 on the contact surface with respect to the other of them. That is to say, only the first high-hardness region 234 may be provided on the output-side carrier 78, or only the second high-hardness region 238 may be provided on the positioning member 232.

[0098] Refer to FIG. 12. From the viewpoint of suppressing the above-mentioned fretting wear, the positioning member 232 may include a low-hardness member 250 provided on the output shaft bearing 44A and 44B sides, and a high-hardness member 252 that contacts the output-side carrier 78 and has a higher surface hardness than the low-hardness member 250. The low-hardness member 250 is constituted by a cylindrical member disposed on the outer peripheral side of the output shaft 42. The high-hardness member 252 is an annular plate-like member that functions as a thrust plate for receiving the thrust load applied from the output-side carrier 78. The high-hardness member 252 has a contact surface that contacts the output-side carrier 78. Thereby, compared with the case where the surface hardness of the high-hardness member 252 is made the same as that of the low-hardness member 250, fretting wear at the contact surface of the high-hardness member 252 due to the relative movement of the output-side carrier 78 with respect to the output shaft 42 can be suppressed. In particular, compared with the case where the positioning member 232 is constituted by only a single member and the entire positioning member 232 is made to have a high hardness, fretting wear at the positioning member 232 can be suppressed with a simple configuration.

[0099] Next, a modified form of each of the components described so far will be described. The tower 12 is taken as the first generator element, and the nacelle 14 is taken as the second generator element. At this time, the plurality of drive devices 24 have been described as rotating the second generator element with respect to the first generator element. Specific examples of the first generator element and the second generator element are not limited to this. For example, when the first generator element is the hub 16 and the second generator element is the blade 18, the drive device 24 may be used as a pitch drive device that rotates the blade 18 with respect to the hub 16. Also in this case, it is sufficient that the plurality of drive devices 24 are arranged in the circumferential direction around the rotation center line of the blade 18.

[0100] Although the speed reduction device 34 has been described as an example of the drive device 24 combined with the motor 32, the speed reduction device 34 may be used alone. The application of the speed reduction device 34 is not limited to wind turbines. The speed reduction device 34 may be used, for example, not only when used as a drive device for a motor roller but also as a drive device for a hoisting machine such as a rolling curtain, a screen, or a blind. In addition to this, the speed reduction device 34 may be used as a drive device for (1) industrial machines such as machine tools and construction machines, (2) robots such as industrial robots and service robots, (3) transportation equipment such as conveyors, and (4) various machines such as vehicles.

[0101] Although the speed reduction device 34 has been described as an example including a multi-stage speed reduction mechanism 38, 40, it is sufficient if at least the second speed reduction mechanism 40 is provided, and the number of stages of the speed reduction mechanisms 38, 40 is not particularly limited. Specific examples of the speed reduction mechanism on the front stage side of the second speed reduction mechanism 40 are not particularly limited, and in addition to the eccentric swing type speed reduction mechanism, a simple planetary type speed reduction mechanism, a flexure engagement type speed reduction mechanism (cylindrical type, silk hat type, cup type, etc.), an orthogonal axis speed reduction mechanism, etc. may be adopted. When only the second speed reduction mechanism 40 is provided, it is sufficient if the rotation of the motor shaft 30 is directly or indirectly transmitted to the second crankshaft 72 of the second speed reduction mechanism 40 so that the rotation is input to the second crankshaft 72.

[0102] The number of the second external gear teeth constituting the first and second gear sets 110, 112 may be three or more. Also, the second external gear teeth of the first gear set 110 adjacent in the axial direction and the second external gear teeth of the second gear set 112 may be provided separately or may be integrally provided by the same member. In terms of the embodiment, the first inner external gear teeth 74B of the first gear set 110 adjacent in the axial direction and the second inner external gear teeth 74C of the second gear set 112 are provided separately, but they may be integrally provided by the same member. Also, the eccentric portions 70A to 70D of the second crankshaft 72 corresponding to these may be integrally provided by the same member or may be provided separately. In terms of the embodiment, the second eccentric portion 70B and the third eccentric portion 70C of the second crankshaft 72 are integrally provided by the same member, but they may be provided separately.

[0103] The second reduction mechanism 40 may be a sorting type in which the second crankshaft 72 is provided at a position offset radially with respect to the swing center C74a of the second external gear teeth 74A to 74D. In the embodiment, the first reduction mechanism 38 is described as a center crank type eccentric swing type reduction mechanism, similar to the second reduction mechanism 40, but a sorting type eccentric swing type reduction mechanism may be employed. The rotating shaft for inputting rotation to the second crankshaft 72 and the second crankshaft 72 may be connected so as not to be relatively movable in the direction orthogonal to the axis.

[0104] All of the eccentric portions 70A to 70D of the second crankshaft 72 may be constituted by a single shaft member 160. Further, the first eccentric portion 70A may have a circular cross-sectional shape with a smaller diameter than the other eccentric portions 70B to 70D. In this case, a cylindrical member provided separately from these may be disposed between the eccentric bearing 86 and the second external gear tooth 74A. This cylindrical member has a radial dimension of the difference in outer diameter between the circular outer diameter exhibited by the first eccentric portion 70A and the circular outer diameter exhibited by the other eccentric portions 70B to 70D. Also in this case, the step formed between the first eccentric portion 70A and the input-side shaft portion 82A can be reduced, which is advantageous for ensuring the durability of the second crankshaft 72.

[0105] At least a part of the main bearing 94 may be disposed radially outward from the center lines C90 and C92 of the pins 90 and 92 when viewed in the axial direction. The retaining member for restricting the removal of the second inner pin 92 may be provided separately from the washer 170.

[0106] The first connection mechanism 120 does not necessarily have to be provided at a position where it can come into contact with the lubricant within the enclosed space 192.

[0107] A seal cap may be attached to the through hole 124 of the output-side carrier 78. The output-side carrier 78 and the positioning member 232 do not necessarily have to be provided with the high-hardness regions 234 and 238. The positioning member 232 does not necessarily have to include the low-hardness member 250 and the high-hardness member 252.

[0108] The above embodiments and modified forms are examples. The technical ideas abstracted from these should not be interpreted restrictively to the content of the embodiments and modified forms. Many design changes such as changes, additions, deletions, etc. of components are possible for the content of the embodiments and modified forms. In the foregoing embodiments, with respect to the content for which such design changes are possible, the notation of "embodiment" is attached and emphasized. However, design changes are also allowed for the content without such notation. The hatching attached to the cross-section of the drawing does not limit the material of the object to which the hatching is attached. Structures and numerical values mentioned in the embodiments and modified forms naturally include those that can be regarded as the same considering manufacturing errors, assembly errors, etc.

[0109] Any combination of the above components is also effective. For example, any explanatory matter of other embodiments may be combined with an embodiment, or any explanatory matter of an embodiment and other modified forms may be combined with a modified form. A component configured by a single member in an embodiment may be configured by a plurality of members. Similarly, a component configured by a plurality of members in an embodiment may be configured by a single member.

Explanation of Reference Numerals

[0110] 10... Wind turbine, 24... Driving device, 34... Reduction device, 42... Output shaft, 44A, 44B... Output shaft bearings, 46... Casing, 70A to 70D... Eccentric parts, 70A... First eccentric part, 70B... Second eccentric part, 72... Second crankshaft, 74A to 74D... Second external gear teeth, 78... Output side carrier, 80... Output rotating body, 88... Input side carrier, 90... Carrier pin, 92... Second inner pin, 94... Main bearing, 98... Bolt, 110... First gear set, 112... Second gear set, 120... First connection mechanism, 124... Through hole, 130... Second connection mechanism, 160... Shaft member, 162... Cylindrical member, 170... Washer, 174, 176... Pin holes, 190, 192... Encapsulated space, 200... Gear housing space, 232... Positioning member, 234, 238... High hardness regions, 250... Low hardness member, 252... High hardness member.

Claims

1. A crankshaft having an eccentric portion, a plurality of external gear wheels oscillated by the eccentric portion, an output rotating body including an output side carrier synchronizable with the rotation component of the external gear wheels, and a reduction gear device comprising an output shaft connected to the output side carrier, wherein the plurality of external gear wheels constitute a first gear set arranged on the input side and a second gear set arranged on the output side, each of the first gear set and the second gear set consists of a plurality of external gear wheels with an eccentric phase shift of 360° / N (N is a natural number of 2 or more) when the number of external gear wheels constituting the gear set is N, the first gear set and the second gear set are such that the arrangement order of the eccentric phases of the respective external gear wheels is axially symmetric, a reduction gear device comprising a first connection mechanism connecting the output side carrier and the output shaft so as to be capable of transmitting torque and allowing relative movement in a direction parallel to the axially orthogonal plane.

2. a rotating shaft connected to the crankshaft and inputting rotation to the crankshaft, and a second connection mechanism connecting the rotating shaft and the crankshaft so as to be capable of transmitting torque and allowing relative movement in a direction parallel to the axially orthogonal plane, according to Claim 1.

3. a casing housing the output rotating body, a main bearing disposed between the output rotating body and the casing, and a pin protruding from the output side carrier and passing through the external gear wheels, according to Claim 1. The entire main bearing is disposed radially inward of the center line of the pin, according to Claim 1.

4. The output rotating body includes an input side carrier disposed on the axially opposite side to the output side carrier with respect to the external gear wheels, the pin includes a carrier pin that cooperates with a bolt to connect the output side carrier and the input side carrier, and an inner pin that transmits the rotation component of the external gear wheels to the output side carrier, a washer disposed between the head of the bolt and the axially outer surface of the output rotating body, the inner pin is fitted into a pin hole opening to the axially outer surface of the output rotating body, the washer is capable of restricting the removal of the inner pin from the pin hole, according to Claim 3.

5. The crankshaft is provided on the oscillation center of the external gear wheels, according to Claim 1.

6. an eccentric bearing disposed between the external gear wheel and the crankshaft, the crankshaft has a plurality of the eccentric portions, The crankshaft includes a shaft member and a cylindrical member provided separately from the shaft member and the eccentric bearing and fitted to the outer peripheral portion of the shaft member. The plurality of eccentric portions include a first eccentric portion that is the most axially input-side. The first eccentric portion is the speed reduction device according to claim 1, which is constituted by the shaft member and the cylindrical member.

7. The plurality of eccentric portions include a second eccentric portion adjacent to the first eccentric portion. The shaft member is the speed reduction device according to claim 6, which does not overlap the outer peripheral surface of the second eccentric portion when viewed axially within the axial range from the first eccentric portion to the input-side end portion.

8. Inside the speed reduction device, an enclosed space is formed in which at least the meshing portion of the external gear and the internal gear is arranged and a lubricant is enclosed. The first connection mechanism is provided at a position where it can contact the lubricant in the enclosed space in the speed reduction device according to claim 1.

9. The enclosed space includes a gear accommodation space for accommodating the external gear. The output-side carrier includes a through hole communicating with the gear accommodation space. The first connection mechanism is arranged in the through hole in the speed reduction device according to claim 8.

10. An output shaft bearing for supporting the output shaft, A positioning member arranged between the output shaft bearing and the output-side carrier for positioning the axial position of the output shaft bearing. In at least one of the positioning member and the output-side carrier, a high-hardness region having a higher surface hardness than other portions is provided on the contact surface with the other member in the speed reduction device according to claim 1.

11. An output shaft bearing for supporting the output shaft, A positioning member arranged between the output shaft bearing and the output-side carrier for positioning the axial position of the output shaft bearing. The positioning member includes a low-hardness member provided on the output shaft bearing side and a high-hardness member that contacts the output-side carrier and has a higher surface hardness than the low-hardness member in the speed reduction device according to claim 1.

12. The first connection mechanism includes a male spline provided on one of the output shaft and the output-side carrier, and a female spline provided on the other of them and meshing with the male spline in the speed reduction device according to claim 1.

13. A first generator element, A second generator element rotatable with respect to the first generator element. A plurality of driving devices arranged in a circumferential direction around the rotation center line of the second generator element and rotating the second generator element. The plurality of driving devices include a wind turbine generator including the speed reduction device according to any one of claims 1 to 12.

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