deceleration device

Abstract

Provided is a speed reduction device that can reduce the number of components. The speed reduction device includes a speed reduction mechanism having an internal gear (21, 22) and an external gear (15), an output member (24) that outputs rotation that has been reduced by the speed reduction mechanism, and a main bearing (28) that supports the output member. The main bearing (28) has an inner ring (28i1, 28i2) and an outer ring (28o1, 28o2) that are made of plate-like members, and at least one of the inner ring and the outer ring has an extension (28e) that constitutes another functional component of the speed reduction device.

Description

[0001] This application claims the benefit of priority based on Japanese Patent Application No. 2020-213390, filed on December 23, 2020. The entire contents of this Japanese application are incorporated herein by reference. Technical Field

[0002] The invention relates to a deceleration device. Background Art

[0003] Conventionally, there is a reduction gear device including a reduction mechanism having an internal gear and an external gear, an output member that outputs the rotation reduced by the reduction mechanism, and a main bearing that supports the output member (see, for example, Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-133843

[0005] The conventional reduction gear transmission having the above-mentioned structure has a problem in that the number of components is large. Summary of the Invention

[0006] An object of the present invention is to provide a reduction gear device capable of reducing the number of components.

[0007] The present invention provides a reduction gear comprising a reduction mechanism having an internal gear and an external gear, an output member for outputting a rotation reduced by the reduction mechanism, and a main bearing supporting the output member, wherein:

[0008] The main bearing has an inner ring and an outer ring composed of plate-like members.

[0009] At least one of the inner ring and the outer ring has an extension portion, and the extension portion constitutes another functional component of the reduction gear.

[0010] According to the reduction gear transmission of the present invention, it is possible to achieve an effect of reducing the number of components. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a cross-sectional view showing a reduction gear transmission according to the first embodiment of the present invention.

[0012] Figure 2 It is a cross-sectional view showing a reduction gear transmission according to a second embodiment of the present invention.

[0013] Figure 3 It is a cross-sectional view showing a reduction gear transmission according to a third embodiment of the present invention.

[0014] In the figure: 1, 1A, 1B-reduction gear, 10-oscillator shaft, 10A-oscillator, 11-oscillator bearing, 15-external gear, 16-stop ring, 21-first internal gear, 22-second internal gear, 24-output component, 28, 28B-main bearing, 28i1, 28i2, 28i1B, 55i1, 55i2-inner ring, 28o1, 28o2, 55o1, 55o2-outer ring, 28e-extension (movement limiting component), 28e2-external gear (extension), 31-eccentric body shaft, 31b, 31c-eccentric body, 34, 36-external gear, 38-internal gear, 41-wheel carrier body (output component), 55-main bearing, 55e1, 55e2-extension, 55ep-inner pin (pin component, extension). DETAILED DESCRIPTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0016] (First embodiment)

[0017] Figure 1 This is a cross-sectional view of a reduction gear transmission according to the first embodiment of the present invention. In this embodiment, the direction along the rotation axis O1 of the vibrator shaft 10 is referred to as the axial direction, the rotation direction centered on the rotation axis O1 is referred to as the circumferential direction, and the direction perpendicular to the rotation axis O1 is referred to as the radial direction. Furthermore, in the axial direction, the side where the output member 24 is located is referred to as the output side, and the side opposite thereto is referred to as the opposite-output side.

[0018] The reduction gear 1 is a flexure meshing gear device and includes an oscillator shaft 10 , an oscillator bearing 11 , an external gear 15 , a first internal gear 21 , a second internal gear 22 , an output member 24 , a cover member 25 , bearings 26 and 27 , a main bearing 28 , and a stop ring 16 .

[0019] The vibrator shaft 10 is an input shaft for inputting rotational motion. The vibrator shaft 10 is a hollow cylindrical shaft that rotates about the rotation axis O1, and includes a vibrator 10A whose cross-section perpendicular to the rotation axis O1 has a non-circular (e.g., elliptical) shape, and shaft portions 10B and 10C provided on both axial sides of the vibrator 10A. The elliptical shape does not need to be an ellipse in the strict geometric sense, and includes a roughly elliptical shape. The shaft portions 10B and 10C are shafts whose cross-section perpendicular to the rotation axis O1 has a circular shape. The material of the vibrator shaft 10 is not particularly limited, but in this embodiment, it is made of a metal such as steel.

[0020] The external gear 15 is a flexible cylindrical member having teeth provided on its outer periphery. The material of the external gear 15 is not particularly limited, but in this embodiment, it is made of metal such as steel.

[0021] The first internal gear 21 is an annular member provided with teeth on a part of its inner periphery. The second internal gear 22 is an annular member provided with internal teeth on its inner periphery. The internal teeth of the first internal gear 21 and the internal teeth of the second internal gear 22 are arranged in the axial direction and mesh with the external gear 15. The first internal gear 21 meshes with a portion of the external gear 15 on the opposite side of the output, and the second internal gear 22 meshes with a portion of the external gear 15 on the output side. The materials of the first internal gear 21 and the second internal gear 22 are not particularly limited, but in the present embodiment, they are made of resin. The type of the resin is not particularly limited, but in the present embodiment, it is made of a PEEK (Poly Ether Ether Ketone) material containing carbon fibers.

[0022] The first internal gear 21 also has an outer peripheral portion extending from one end portion and the other end portion thereof in the axial direction toward the opposite side of the output and the output side, respectively. This outer peripheral portion functions as an outer shell covering the meshing portions of the external gear 15, the first internal gear 21, and the second internal gear 22 from the radially outer side.

[0023] The vibration body bearing 11 is, for example, a roller bearing, and is disposed between the vibration body 10A and the external gear 15. The vibration body bearing 11 does not have a dedicated outer ring and inner ring, and the inner peripheral portion of the external gear 15 functions as the outer ring of the vibration body bearing 11, and the outer peripheral portion of the vibration body 10A functions as the inner ring of the vibration body bearing 11. Alternatively, the vibration body bearing 11 can have a dedicated outer ring and inner ring. The external gear 15 is supported by the vibration body 10A so as to be relatively rotatable via the vibration body bearing 11. The material of the rolling element of the vibration body bearing 11 is not particularly limited, but in the present embodiment, it is made of a metal such as a steel material.

[0024] The stop ring 16 is disposed on the opposite side of the output from the external gear 15 and the vibration body bearing 11, and restricts the movement of the external gear 15 and the vibration body bearing 11 toward the opposite side of the output. The material of the stop ring 16 is not particularly limited, but in the present embodiment, it is made of a metal such as a steel material.

[0025] The inner ring 28il of the main bearing 28 has an extension portion 28e on the output side of the external gear 15 and the vibration body bearing 11. The extension portion 28e functions as a movement restriction member that restricts the movement of the external gear 15 and the vibration body bearing 11 toward the output side.

[0026] The output member 24 is located on the output side of the reduction gear 1 and is connected to the second internal gear 22, thereby outputting the reduced rotation. The output member 24 can be an annular structure that passes through the center without closing the hollow portion of the oscillator shaft 10. The material of the output member 24 is not particularly limited, but in this embodiment, it is made of resin. The type of resin is not particularly limited, but in this embodiment, it is made of POM (Polyoxymethylene, Polyacetal) material containing carbon fibers.

[0027] The reduction mechanism is composed of the vibrator 10A, the vibrator bearing 11, the external gear 15, the first internal gear 21, and the second internal gear 22. The first internal gear 21 is directly or indirectly connected to the external support member 81 that supports the reduction gear 1. The reduction mechanism reduces the rotation input to the vibrator 10A and outputs the reduced rotation to the second internal gear 22. The second internal gear 22 and the output member 24 are connected to the external counterpart member 82. The second internal gear 22 and the output member 24 output the reduced rotation of the reduction mechanism to the counterpart member 82.

[0028] The cover member 25 is located on the opposite-to-output side of the reduction gear 1 and covers the meshing portion between the external gear 15 and the first internal gear 21 from the opposite-to-output side. The cover member 25 is coupled to the first internal gear 21. The material of the cover member 25 is not particularly limited; however, in this embodiment, it is made of resin. The type of resin is not particularly limited; however, in this embodiment, it is made of a POM material containing carbon fibers.

[0029] Bearings 26 and 27 are, for example, ball bearings, but the type of bearing is not particularly limited. Bearing 26 is located between cover member 25 and vibrator shaft 10, supporting them for relative rotation. Bearing 27 is located between output member 24 and vibrator shaft 10, supporting them for relative rotation.

[0030] The main bearing 28 is located between the first internal gear 21, the second internal gear 22, and the output member 24, and supports them so that they can rotate relative to each other. The main bearing 28 is a crossed roller bearing, and a single bearing can bear radial loads and bidirectional axial loads. Furthermore, the main bearing 28 can also be a structure that can bear moment loads as a single bearing. A single bearing means a structure that cannot be separated into multiple components that function as bearings when only the bearing is removed. In addition, the main bearing 28 is not limited to a crossed roller bearing. Other bearings that can bear radial loads and bidirectional axial loads as a single bearing, such as a four-point contact ball bearing, can also be used. Furthermore, the main bearing is not limited to a single bearing that can bear radial loads and bidirectional axial loads. Various bearings can be used, for example, a pair of bearings. In this case, the present invention can be applied to a pair of bearings or only to one of the bearings. Furthermore, a bearing that cannot bear a portion of the radial load and bidirectional axial load can also be used.

[0031] <Deceleration action>

[0032] If rotational motion is input to the vibrator shaft 10 from the outside, the rotational motion of the vibrator 10A is transmitted to the external gear 15. At this time, the shape of the external gear 15 is restricted to conform to the shape of the outer peripheral surface of the vibrator 10A, and when viewed from the axial direction, it is bent into an elliptical shape with a major axis portion and a minor axis portion. Moreover, the major axis portion of the external gear 15 meshes with the fixed first internal gear 21. Therefore, the external gear 15 does not rotate at the same speed as the vibrator 10A, but the vibrator 10A rotates relative to the inside of the external gear 15. Moreover, as this relative rotation occurs, the external gear 15 is flexed and deformed in such a way that the major axis position and the minor axis position move in the circumferential direction. This deformation period is proportional to the rotation period of the vibrator shaft 10.

[0033] When the external gear 15 flexes, its major axis shifts, causing the meshing position between the external gear 15 and the first internal gear 21 to change in the rotational direction. If the number of teeth on the external gear 15 is 100 and the number of teeth on the first internal gear 21 is 102, the meshing position shifts with each rotation of the external gear 15 and the first internal gear 21, causing the external gear 15 to rotate (rotate). With this number of teeth, the rotational motion of the oscillating shaft 10 is reduced by a reduction ratio of 100:2 and then transmitted to the external gear 15.

[0034] On the other hand, the external gear 15 also meshes with the second internal gear 22. Therefore, as the vibrator shaft 10 rotates, the meshing position between the external gear 15 and the second internal gear 22 also changes in the rotational direction. However, because the number of teeth on the second internal gear 22 matches that on the external gear 15, the external gear 15 and the second internal gear 22 do not rotate relative to each other. The rotational motion of the external gear 15 is transmitted to the second internal gear 22 at a reduction ratio of 1:1. Consequently, the rotational motion of the vibrator shaft 10 is reduced in speed at a reduction ratio of 100:2 and then transmitted to the second internal gear 22 and the output member 24. This reduced rotational motion is then output from the output member 24 to the target member 82.

[0035] If radial loads or bidirectional axial loads are applied between the outer support member 81 and the mating member 82 during deceleration operation of the reduction gear 1, these loads are borne by the main bearing 28, thereby enabling the reduction gear 1 to continue its deceleration operation without hindrance. Furthermore, if moment loads are applied between the outer support member 81 and the mating member 82 during deceleration operation of the reduction gear 1, these moment loads are also borne by the main bearing 28, thereby also achieving the effect of enabling the above-mentioned deceleration operation to continue without hindrance.

[0036] <Inner and outer rings of the main bearing>

[0037] The main bearing 28 includes inner rings 28i1 and 28i2 formed of plate-like components, outer rings 28o1 and 28o2 formed of plate-like components, and roller-shaped rolling elements 28t. If the main bearing 28 is a four-point contact ball bearing, the rolling elements 28t are spherical. The plate-like components can be made of metal such as steel.

[0038] The inner rings 28i1, 28i2 and the outer rings 28o1, 28o2 are formed by bending plate-like parts by stamping, and Figure 1 At least the plate-shaped portion of the cross-sectional shape that constitutes the rolling surface (also called the raceway surface) has a circumferentially continuous annular shape. Outer rings 28o1 and 28o2 are located on the output side and the opposite side of the output, respectively. They are composed of two separate components and each includes a rolling surface for rolling elements 28t. Similarly, inner rings 28i1 and 28i2 are located on the output side and the opposite side of the output, respectively. They are composed of two separate components and each includes a rolling surface for rolling elements 28t. Rolling elements (rollers) having a rotation axis x1 roll on the rolling surfaces of inner ring 28i1 and outer ring 28o2, while rolling elements (rollers) having a rotation axis x2 roll on the rolling surfaces of inner ring 28i2 and outer ring 28o1. Inner ring 28i1 is an example of the first inner ring component of the present invention, and inner ring 28i2 is an example of the second inner ring component of the present invention.

[0039] By forming the inner rings 28i1 and 28i2 and the outer rings 28o1 and 28o2 from plate-like members, it is possible to reduce the weight and cost of the main bearing 28.

[0040] The outer rings 28o1 and 28o2 also have radially outwardly extending flanges 28f1 and connecting holes (e.g., through-holes) h28o provided in the flanges 28f1. The flanges 28f1 can be continuous along the entire circumference or provided at multiple locations along the circumference. The connecting holes h28o are provided at multiple locations along the circumference.

[0041] The first internal gear 21 includes a flange portion 21f located at a position overlapping the flange portion 28f1 when viewed axially, and connecting holes (e.g., screw holes) h21 provided in the flange portion 21f. The flange portion 21f may be provided continuously along the entire circumference or may be provided at multiple locations along the circumference. The connecting holes h21 are provided at multiple locations along the circumference.

[0042] The flange portions 28f1 of the outer rings 28o1 and 28o2 are connected to the flange portion 21f of the first internal gear 21 via connecting holes h28o and h21 using connecting members B1 such as bolts. Furthermore, the flange portions 28f1 and 21f can be connected to the outer support member 81 via connecting holes h28o and h21 using connecting members B2 such as bolts.

[0043] The inner rings 28i1 and 28i2 also have radially inwardly extending flanges 28f2 and connecting holes (e.g., through-holes) h28i provided in the flanges 28f2. The flanges 28f2 can be continuous along the entire circumference or provided at multiple locations along the circumference. The connecting holes h28i are provided at multiple locations along the circumference.

[0044] The second internal gear 22 is provided with connection holes (eg, screw holes) h22 at a plurality of locations in the circumferential direction.

[0045] The output member 24 is provided with connection holes (eg, through holes) h24a and h24b at a plurality of locations in the circumferential direction.

[0046] The output member 24, the flange portion 28f2 of the inner rings 28i1 and 28i2, and the second internal gear 22 are connected together via their respective connecting holes h24a, h28i, and h22, and by connecting members B3 such as bolts. Furthermore, the external mating member 82 can be connected to the output member 24, the flange portion 28f2, and the second internal gear 22 via connecting holes h24b, h28i, and h22 in the output member 24, the flange portion 28f2, and the second internal gear 22, and by connecting members B4 such as bolts.

[0047] The inner ring 28il further has an extension 28e that extends toward the radially inner side and is continuous in the circumferential direction, and is circular-plate-shaped (central-through circular-plate-shaped, i.e., ring-shaped). The inner ring 28il having the extension 28e is positioned at a position that is more on the inner side of the device in the axial direction than the other inner ring 28i2. The inner side of the device refers to the side that is close to the center of the reduction mechanism (the center of the meshing portions of the outer gear 15 and the first and second inner gears 21 and 22) in the axial direction.

[0048] As described above, the extension 28e constitutes a functional component other than a bearing, and specifically functions as a movement restriction component that restricts movement of the outer gear 15 and the vibration body bearing 11 toward the output side.

[0049] A plate-shaped member easily achieves high thickness accuracy and desired surface properties. Therefore, the extension 28e of the inner ring 28il constituted by a plate-shaped member can have high thickness accuracy and surface properties suitable for a movement restriction component even without implementing a high-cost processing.

[0050] Further, the extension 28e extends to a position that overlaps the outer ring of the bearing 27 when viewed in the axial direction, and thus can contact the entire side surface of the cage of the vibration body bearing 11. By this contact, movement of the vibration body bearing 11 can be stably restricted. Such a structure that contacts the entire side surface of the cage to restrict movement of the vibration body bearing 11 is not easily achieved other than by providing a separate stopper member or by providing an extension on one or both of the inner rings 28il and 28i2. For example, if a portion of the output member 24 is extended instead of the extension 28e to provide the same movement restriction component, the following difficulty arises. That is, the outer ring of the bearing 27 is inserted into the inner peripheral portion of the output member 24 from the side opposite to the output and is positioned by abutting against the protruding portion 24a of the output member 24 that protrudes toward the radially inner side. Therefore, if a portion of the output member 24 is extended instead of the extension 28e to the vicinity of the vibration body bearing 11, assembly of the bearing 27 and the output member 24 becomes difficult. However, in the first embodiment, the extension 28e is provided on the inner ring 28i2, and thus a portion of the inner ring 28i2 functions as a movement restriction component, and thus the above difficulty does not arise, and the inner ring 28i2 having the movement restriction component (extension 28e) can be assembled to the device.

[0051] In the first embodiment, the outer ring of the main bearing 28 is constructed from two components (outer rings 28o1 and 28o2), and the inner ring is constructed from two components (inner rings 28i1 and 28i2). However, the outer ring can also be constructed from a single plate-shaped component, or the inner ring can be constructed from a single plate-shaped component, by stamping or other means. Furthermore, the structure of the first embodiment can include an extension extending continuously from one end of either outer ring 28o1 or 28o2 toward the opposite side of the output. This extension can function as a radially outer shell covering the meshing portion between the external gear 15 and the first and second internal gears 21 and 22. The outer ring with this extension can be the outer ring 28o1 located axially inward of the device. In this case, the extension can be made small and can function as a shell without having to be processed into a complex shape.

[0052] As described above, the reduction gear 1 according to the first embodiment includes: a reduction mechanism having a first internal gear 21, a second internal gear 22, and an external gear 15; an output member 24 that outputs the rotation reduced by the reduction mechanism; and a main bearing 28 that supports the output member 24. Furthermore, the main bearing 28 includes inner rings 28i1 and 28i2 and outer rings 28o1 and 28o2, each formed of plate-like components. The inner ring 28i1 has an extension 28e, which constitutes another functional component of the reduction gear 1. Therefore, the inner ring 28i1 is integrated with the other functional components, thereby reducing the number of components. Furthermore, by forming the inner rings 28i1, 28i2 and outer rings 28o1 and 28o2 of the main bearing 28 from plate-like components, the main bearing 28 is lighter than a main bearing having block-shaped inner and outer rings, thereby reducing the weight of the reduction gear 1.

[0053] Specifically, the extension 28e functions as a movement-limiting member, restricting the movement of other components. Because the inner ring 28i1 is constructed from a plate-like member, the extension 28e can achieve high thickness accuracy and easily achieve the desired surface properties. Consequently, the extension 28e functions effectively as a movement-limiting member.

[0054] More specifically, the extension 28e restricts the output-side movement of the external gear 15. Since the external gear 15 slides on the extension 28e and the extension 28e restricts the movement of the external gear 15, the extension 28e needs to have a surface property that resists sliding. However, since the inner ring 28i1 is formed of a plate-like member, such a surface property can be easily achieved.

[0055] Furthermore, in the reduction gear transmission 1 of the first embodiment, the inner races 28i1 and 28i2 are constructed from two separate components, with one inner race 28i2 having the extension 28e. This makes the machining of the rolling surface of the rolling element 28t easier, and the inclusion of the extension 28e on one inner race 28i1 facilitates molding and assembly of the extension 28e, compared to using overlapping extensions on both inner races 28i1.

[0056] Furthermore, according to the reduction gear 1 of the first embodiment, the inner ring 28i1, which is positioned axially inward of the inner rings 28i1 and 28i2, is provided with an extension portion 28e. Therefore, the extension portion 28e can be made small and can be used as a functional component of the reduction gear mechanism without having to be machined into a complex shape to avoid interference with other components.

[0057] Furthermore, according to the reduction gear 1 of the first embodiment, the main bearing 28 is constructed as a single bearing capable of supporting both radial and bidirectional axial loads. Therefore, compared to a configuration in which two main bearings are provided at different axial positions, the total number of components in the reduction gear 1 can be reduced. Furthermore, since the two separate inner rings 28i1 and 28i2 and the two separate outer rings 28o1 and 28o2 easily form a bearing capable of supporting such loads, in addition to the aforementioned advantages of the separate inner rings 28i1 and 28i2, the construction of the inner rings 28i1 and 28i2 from two separate components further facilitates the formation of a bearing capable of supporting such loads.

[0058] Furthermore, according to the reduction gear transmission 1 of the first embodiment, the inner rings 28i1, 28i2 and the outer rings 28o1, 28o2 are formed from plate-like members bent by stamping. This reduces the manufacturing costs of the inner rings 28i1, 28i2 and the outer rings 28o1, 28o2, and also reduces the component costs of the reduction gear transmission 1.

[0059] (Second embodiment)

[0060] Figure 2 This is a cross-sectional view of a reduction gear transmission according to a second embodiment of the present invention. In the second embodiment, the direction along the rotation axis O1 of the eccentric shaft 31 is referred to as the axial direction, the rotation direction centered on the rotation axis O1 is referred to as the circumferential direction, and the direction perpendicular to the rotation axis O1 is referred to as the radial direction. Furthermore, in the axial direction, the side of the carrier body 41 on which the decelerated rotational motion is output (the side of the carrier body 41 relative to the external gears 34 and 36) is referred to as the output side, and the side opposite thereto is referred to as the output opposite side.

[0061] The reduction gear 1A of the second embodiment is an eccentric swing type reduction gear in which the external gears 34, 36 are eccentrically swung, and it has: an eccentric shaft 31 having two eccentric bodies 31b, 31c; two external gears 34, 36; an internal gear 38 engaged with the external gears 34, 36; eccentric shaft bearings 51, 52; an internal pin 55ep engaged with the external gears 34, 36; a carrier body 41 linked with the internal pin 55ep; a cover member 46 covering the portions where the external gears 34, 36 are swung from the opposite side of the output; and a main bearing 55 present between the carrier body 41 and the internal gear 38. The carrier body 41 corresponds to an example of the output member according to the present application. The internal pin 55ep corresponds to an example of the pin member according to the present application.

[0062] Further, the reduction gear 1A has: a stop ring 44 disposed between the external gear 34 and the cover member 46; a stop ring 45 disposed between the two external gears 34, 36; a washer 48 attached to the shaft portion 31a1 of the eccentric shaft 31; a seal 47 present between the washer 48 and the cover member 46; and high-speed bearings 53, 54 supporting the eccentric shaft 31.

[0063] The eccentric shaft 31 has shaft portions 31a1, 31a2, 31a3 in which the rotational axis O1 and the central axis overlap, and eccentric bodies 31b, 31c disposed eccentrically from the rotational axis O1. As for the eccentric bodies 31b, 31c, the cross section perpendicular to the rotational axis O1 is circular, and they are eccentrically rotated at different phases from each other with the rotation of the eccentric shaft 31.

[0064] The external gear 34 is assembled to the eccentric body 31b via the eccentric shaft bearing 51, and it is swung with the rotation of the eccentric shaft 31. The other external gear 36 is assembled to the eccentric body 31c via the eccentric shaft bearing 52, and it is swung at a different phase from the external gear 34 with the rotation of the eccentric shaft 31. The external gear 34 is provided with an internal pin hole 34h through which the internal pin 55ep passes. Similarly, the external gear 36 is provided with an internal pin hole 36h through which the internal pin 55ep passes.

[0065] The internal pin 55ep and the internal pin holes 34h, 36h can be provided with one each, or a plurality of them can be provided at a plurality of positions in the circumferential direction.

[0066] The internal pin 55ep is in contact with the inner circumferential surface of the internal pin holes 34h, 36h via the sleeve 49, and it moves (including being stationary) in synchronization with the movement (rotational movement) of the external gears 34, 36. Specifically, it revolves in synchronization with the rotation of the external gears 34, 36, thereby causing the carrier body 41 to rotate, or in the case where the rotation of the external gears 34, 36 is restricted, it also revolves, and the carrier body 41 also rotates.

[0067] The carrier body 41 is arranged on the output side of the two external gears 34 and 36 , and is connected to the inner rings 55i1 and 55i2 and the inner pin 55ep of the main bearing 55 .

[0068] The high-speed bearings 53 and 54 are not particularly limited in type and may be, for example, ball bearings. One high-speed bearing 53 is positioned between the cover member 46 and the shaft portion 31a2 of the eccentric shaft 31, supporting them for relative rotation. The other high-speed bearing 54 is positioned between the carrier body 41 and the shaft portion 31a3 of the eccentric shaft 31, supporting them for relative rotation.

[0069] The main bearing 55 supports the internal gear 38 and the wheel carrier body 41 for relative rotation. The main bearing 55 is a crossed roller bearing, and a single bearing can support radial loads and bidirectional axial loads. Furthermore, the main bearing 55 can also be a structure that can support moment loads. Furthermore, the main bearing 55 is not limited to a crossed roller bearing; for example, other bearings that can support radial loads and bidirectional axial loads can also be used, such as a four-point contact ball bearing.

[0070] <Deceleration action>

[0071] In the reduction gear 1A having the above-described structure, the internal gear 38 is directly or indirectly connected to the external support member 81 via a connecting member B13 such as a bolt, and the carrier body 41 is directly or indirectly connected to the external counterpart member 82 via a connecting member B12 such as a bolt. Furthermore, when rotational motion is input from the outside to the eccentric shaft 31, the reduction gear 1A decelerates the input rotation and outputs the decelerated rotation from the carrier body 41 to the counterpart member 82.

[0072] Specifically, when the eccentric shaft 31 rotates, the eccentric bodies 31b and 31c rotate eccentrically, causing one external gear 34 and the other external gear 36 to oscillate with a phase difference of 180 degrees. The presence of two external gears 34 and 36 increases transmission capacity and maintains strength, while also maintaining the rotational balance of the reduction gear 1A. The external gears 34 and 36 internally mesh with the internal gear 38, which is connected to the support member 81. Therefore, for each rotation of the eccentric shaft 31, the external gears 34 and 36 rotate (autorotate) relative to the internal gear 38 by an amount corresponding to the difference in the number of teeth. The rotational component of the external gears 34 and 36 is transmitted to the carrier body 41 via the inner pin 55ep. As a result, the rotational motion of the eccentric shaft 31 is reduced in speed by a reduction ratio of (the difference in the number of teeth between the internal gear 38 and the external gears 34 and 36) / (the number of teeth of the external gears 34 and 36) and then transmitted to the carrier body 41. Then, the reduced-speed rotation is output from the carrier body 41 to the counterpart member 82 .

[0073] If radial loads or bidirectional axial loads are applied between the outer support member 81 and the mating member 82 during deceleration operation of the reduction gear 1A, these loads are borne by the main bearing 55, thereby enabling the reduction gear 1A to continue its deceleration operation without hindrance. Furthermore, if moment loads are applied between the outer support member 81 and the mating member 82 during deceleration operation of the reduction gear 1A, these moment loads are also borne by the main bearing 55, thereby also achieving the effect of enabling the above-mentioned deceleration operation to continue without hindrance.

[0074] Alternatively, the reduction gear 1A may have a structure in which the carrier body 41 is directly or indirectly connected to a supporting member, the internal gear 38 is directly or indirectly connected to a target member, and the reduced rotation is output to the target member via the internal gear 38. In this case, the internal gear 38 or the cover member 46 connected to the internal gear 38 corresponds to an example of the output member involved in the present invention.

[0075] <Inner and outer rings of the main bearing>

[0076] The main bearing 55 includes inner rings 55i1 and 55i2 formed of plate-like members, outer rings 55o1 and 55o2 formed of plate-like members, and roller-shaped rolling elements 55t. If the main bearing 55 is a four-point contact ball bearing, the rolling elements 55t are spherical.

[0077] The inner rings 55i1, 55i2 and the outer rings 55o1, 55o2 are formed by bending plate-like parts by stamping, and Figure 1 At least the plate-like portion of the cross-sectional shape that constitutes the rolling surface (also called the raceway surface) has a circumferentially continuous annular shape. The outer rings 55o1 and 55o2 are composed of two components, one on the output side and the other side opposite the output, and each includes a rolling surface for the rolling element 55t. Similarly, the inner rings 55i1 and 55i2 are composed of two components, one on the output side and the other side opposite the output, and each includes a rolling surface for the rolling element 55t. The rolling elements (rollers) with a rotation axis x1 roll on the rolling surfaces of the inner ring 55i1 and the outer ring 55o2, while the rolling elements (rollers) with a rotation axis x2 roll on the rolling surfaces of the inner ring 55i2 and the outer ring 55o1.

[0078] By forming the inner rings 55i1 and 55i2 and the outer rings 55o1 and 55o2 from plate-like members, it is possible to reduce the weight and cost of the main bearing 55.

[0079] The outer rings 55o1 and 55o2 also have radially outwardly extending flanges 55f1 and connecting holes (e.g., through-holes) h55o provided in the flanges 55f1. The flanges 55f1 can be continuous along the entire circumference or provided at multiple locations along the circumference. The connecting holes h55o are provided at multiple locations along the circumference.

[0080] The internal gear 38 is provided with connection holes (eg, screw holes) h38 at a plurality of locations in the circumferential direction.

[0081] The flange 55f1 of the outer rings 55o1 and 55o2 is connected to the internal gear 38 via the connecting holes h55o and h38 using bolts or other fastening members B11. Alternatively, the flange 55f1 can be used to connect to an external support member. In this case, the support member is connected to the flange 55f1 and the internal gear 38 via the connecting holes h55o and h38 using bolts or other fastening members.

[0082] The inner rings 55i1 and 55i2 also have radially inwardly extending flanges 55f2 and connection holes (e.g., through-holes) h55i provided in the flanges 55f2. The flanges 55f2 can be continuous along the entire circumference or provided at multiple locations along the circumference. The connection holes h55i are provided at multiple locations along the circumference.

[0083] The carrier body 41 is provided with connection holes (eg, through holes) h41 at a plurality of locations in the circumferential direction.

[0084] The flange portion 55f2 of the inner rings 55i1 and 55i2 is connected to the wheel carrier body 41 through the connection holes h55i and h41 and by a connection member B12 such as a bolt. Furthermore, the external object component 82 can be connected to the flange portion 55f2 and the wheel carrier body 41 through the connection holes h55i and h41 in the flange portion 55f2 and the wheel carrier body 41 and by a connection member B12 such as a bolt.

[0085] The inner ring 55i1 also has an extension portion 55e1 extending radially inward. The inner ring 55i1 having the extension portion 55e1 is located closer to the inside of the device (axially inner side) than the other inner ring 55i2. Moreover, the extension portion 55e1 has a hollow inner pin 55ep protruding in a pin shape toward the opposite side of the output. The inner pin 55ep is formed by deep drawing the plate. The extension portion 55e1 can be a circular plate shape that is continuous in the circumferential direction (a circular plate shape with a through center) or a structure with a cutout on a part of the circumferential direction. The inner pin 55ep is provided at one or more locations in the circumferential direction. The inner pin 55ep passes through the through hole of the wheel carrier body 41 from the output side toward the opposite side of the output and protrudes toward the side of the external gears 34 and 36.

[0086] The other inner ring 55i2 also has an extension portion 55e2 extending radially inward. The extension portion 55e2 can be a circumferentially continuous disc (a disc with a central through-hole) or can have a circumferentially cutout portion. The extension portion 55e2 closes the opening at the base of the inner pin 55ep.

[0087] As described above, the reduction gear 1A according to the second embodiment includes a reduction mechanism having an internal gear 38 and external gears 34 and 36, a carrier body (output member) 41 that outputs rotation reduced by the reduction mechanism, and a main bearing 55 that supports the carrier body 41. Furthermore, the main bearing 55 includes inner rings 55i1 and 55i2 and outer rings 55o1 and 55o2, each formed of plate-like components. The inner ring 55i1 has an extension 55e1 (including an inner pin 55ep), which constitutes another functional component (the inner pin 55ep) of the reduction gear 1A. Therefore, the inner ring 55i1 is integrated with the other functional components, thereby reducing the number of components. Furthermore, by forming the inner rings 55i1 and 55i2 and the outer rings 55o1 and 55o2 of the main bearing 55 from plate-like components, the main bearing 55 is lighter than a main bearing having block-shaped inner and outer rings, thereby reducing the weight of the reduction gear 1A.

[0088] Specifically, the extension portion 55e1 of the inner ring 55i1 constitutes the inner pin 55ep that is synchronized with the rotational component of the external gears 34 and 36. Therefore, one or more inner pins 55ep can be integrated, and the assembly process of the inner pin 55ep can be simplified.

[0089] Furthermore, in the reduction gear transmission 1A of the second embodiment, similar to the first embodiment, the inner rings 55i1 and 55i2 are constructed from two separate components, and the main bearing 55 is configured so that a single bearing supports both radial loads and bidirectional axial loads. Furthermore, the inner rings 55i1 and 55i2 and the outer rings 55o1 and 55o2 are constructed from plate-like members formed by bending the plate-like members through press forming. Consequently, the same effects as those described above in the first embodiment are achieved.

[0090] (Third embodiment)

[0091] Figure 3 This is a cross-sectional view of a reduction gear according to the third embodiment. The third embodiment is a modification of a portion of the first embodiment. Components identical to those of the first embodiment are designated by the same reference numerals, and detailed descriptions are omitted. The reduction gear 1B of the third embodiment is a so-called top-hat flexural meshing gear mechanism. The reduction gear mechanism comprises an external gear 28e2 having a flange 28f3, an internal gear 21B, and an oscillating bearing 11B corresponding to the internal gear 21B. Furthermore, the reduction gear 1B of the third embodiment includes a main bearing 28B in which an extension of the inner race 28i1B functions as the external gear 28e2.

[0092] The structure of the internal gear 21B is the same as that of the first internal gear 21 of the first embodiment. The reduction gear 1B of the third embodiment does not include a second internal gear.

[0093] The external gear 28e2 is a metal member having a cylindrical portion and a flange portion 28f3 extending radially outward from one end of the cylindrical portion. External teeth G1 are provided in the cylindrical portion within a range facing the internal gear 21B (its internal teeth portion).

[0094] The vibrator bearing 11B is located between the vibrator 10A and the external gear 28e2 and supports the vibrator 10A and the external gear 28e2 so that they can rotate relative to each other. The vibrator bearing 11B is provided at a position corresponding to the meshing portion between the external gear 28e2 and the internal gear 21B (radially inside the meshing portion).

[0095] The vibrator shaft 10 has the same structure as that of the first embodiment, and further includes a protrusion 10e located near one end of the vibrator bearing 11B. The protrusion 10e restricts movement of the vibrator bearing 11B toward the output side.

[0096] The flange portion 28f3 of the external gear 28e2 is connected to the output member 24.

[0097] The main bearing 28B is located between the internal gear 21B, the output member 24, and the flange portion 28f3 of the external gear 28e2, and supports the internal gear 21B and the output member 24, and the internal gear 21B and the external gear 28e2, so that they can rotate freely relative to each other. The main bearing 28B is identical to the main bearing 28B of the first embodiment, except for the extension portion of the inner ring 28i1B.

[0098] <Deceleration action>

[0099] When rotational motion is externally input to the vibrator shaft 10, the rotational motion of the vibrator 10A is transmitted to the external gear 28e2. At this point, the shape of the external teeth of the external gear 28e2 is constrained to conform to the shape of the outer circumference of the vibrator 10A. When viewed axially, it is curved into an elliptical shape with a major axis and a minor axis. Furthermore, the major axis of the external gear 28e2 meshes with the fixed internal gear 21B. Therefore, the external gear 28e2 does not rotate at the same speed as the vibrator 10A. Instead, the vibrator 10A rotates relative to the internal gear 28e2, causing the external gear 28e2 to flex and deform, shifting its major and minor axis positions circumferentially. Furthermore, as the major axis position shifts, the meshing position of the external gear 28e2 and the internal gear 21B changes in the rotational direction. Here, if the number of teeth on the external gear 28e2 is 100 and the number of teeth on the internal gear 21B is 102, the meshing teeth of the external gear 28e2 and the internal gear 21B gradually shift with each rotation of the meshing position, causing the external gear 28e2 to rotate (rotate). With this number of teeth, the rotational motion of the oscillator shaft 10 is reduced by a reduction ratio of 100:2 and transmitted to the external gear 28e2. The rotation of the external gear 28e2 is then transmitted to the output member 24 via the flange portion 28f3, and the reduced rotation is output from the output member 24 to the external counterpart member 82.

[0100] If radial loads or bidirectional axial loads are applied between the outer support member 81 and the mating member 82 during deceleration operation of the reduction gear 1B, these loads are borne by the main bearing 28B, thereby enabling the reduction gear 1B to continue its deceleration operation without hindrance. Furthermore, if moment loads are applied between the outer support member 81 and the mating member 82 during deceleration operation of the reduction gear 1B, these moment loads are also borne by the main bearing 28B, thereby also achieving the effect of enabling the above-mentioned deceleration operation to continue without hindrance.

[0101] <Inner and outer rings of the main bearing>

[0102] The main bearing 28B comprises two-component inner rings 28i1B and 28i2, and two-component outer rings 28o1 and 28o2. The inner ring 28i1B, located on the inside of the device, has an extension (external gear 28e2) that serves as another functional component. This extension is an axially extending cylindrical portion that, as described above, forms the top-hat-shaped external gear 28e2.

[0103] Furthermore, the flange portion 28f3 of the inner race 28i1B is provided with a screw hole h28B threaded with a tap or the like, which is threadedly engaged with fastening members B6 and B7, such as bolts. Furthermore, the output member 24 is connected to the inner races 28i1B and 28i2 via the fastening holes h24a and h28i and the screw hole h28B, using fastening members B6, such as bolts. This structure eliminates the need for nuts connecting the inner races 28i1B and 28i2 to the output member 24, further reducing the number of components. Furthermore, the output member 24 is connected to the external counterpart 82 via the fastening holes h24b and h28i and the screw hole h28B, using fastening members B7, such as bolts. This structure eliminates the need for nuts connecting the counterpart 82 to the output member 24, further reducing the number of components.

[0104] Alternatively, the reduction gear 1B can be configured such that the inner rings 28i1B, 28i2 and the external gear 28e2 are connected to an external support member, while the outer rings 28o1, 28o2 and the internal gear 21B are connected to an external counterpart. In this case, the rotational motion input to the vibrating shaft 10 is reduced in speed and transmitted to the internal gear 21B, from which it is then output to the external counterpart. In this case, the internal gear 21B functions as an output member that outputs the reduced rotational motion.

[0105] Furthermore, in a configuration where the internal gear 21B functions as an output member, the connecting hole h28o of the outer ring 28o2 can be formed by a threaded hole formed using a tap, etc., while the connecting hole h21 of the internal gear 21B can be formed by a through-hole. Furthermore, a bolt can be threaded from the connecting hole h21 of the internal gear 21B (e.g., a through-hole) through the connecting hole h28o of the outer rings 28o1 and 28o2 and then screwed into the connecting hole h28o (threaded hole) of the other outer ring 28o2, thereby connecting the output member (i.e., the internal gear 21B) to the outer rings 28o1 and 28o2.

[0106] As described above, the reduction gear 1B according to the third embodiment includes a reduction mechanism having an internal gear 21B and an external gear 15; an output member 24 that outputs the rotation reduced by the reduction mechanism; and a main bearing 28B that supports the output member 24. Furthermore, the main bearing 28B includes inner rings 28i1B and 28i2 and outer rings 28o1 and 28o2, each formed of plate-like components. The inner ring 28i1B has an extension 28e2, which constitutes another functional component. Therefore, the inner ring 28i1B is integrated with the other functional components, reducing the number of components. Furthermore, by forming the inner rings 28i1B, 28i2 and outer rings 28o1 and 28o2 of the main bearing 28B from plate-like components, the main bearing 28B is lighter than a main bearing having block-shaped inner and outer rings, thereby reducing the weight of the reduction gear 1B.

[0107] Specifically, the extension portion 28e2 of the inner ring 28i1B constitutes the external gear 28e2 that is deformed. By using a plate-shaped member (ie, the extension portion of the inner ring 28i1B), the characteristic of deforming the external gear 28e2 is easily obtained.

[0108] Furthermore, in the reduction gear 1B according to the third embodiment, the inner ring 28i1B has screw holes h28B that threadably engage with fastening members B6 and B7, such as bolts. Therefore, when fastening the inner rings 28i1B and 28i2, or when fastening the inner rings 28i1B and 28i2 to other components (such as the output member 24 and the external gear 28e2), nuts are not required unless there are any parts that function as nuts, thus reducing the number of components.

[0109] The various embodiments of the present invention have been described above. However, the present invention is not limited to the above-mentioned embodiments. For example, in the above-mentioned embodiments, a so-called cylindrical flexural meshing gear device, a center crank type eccentric oscillating type reduction gear device, and a so-called top hat type flexural meshing gear device are shown. However, the present invention can also be applied to various reduction gear devices such as a so-called cup-type flexural meshing gear device, a so-called distributed eccentric oscillating type reduction gear device having two or more eccentric shafts of an eccentric body arranged at a position offset from the axial center of the reduction gear device, or a simple planetary gear device. When the present invention is applied to a simple planetary gear device, a structure in which a pin component is formed by an extension of the inner ring and the pin component is synchronized with the revolution component of the planetary gear (external gear) can be adopted in the same manner as in the second embodiment. In addition, the detailed structure shown in the embodiment can be appropriately changed within the scope of the purpose of the invention.

Claims

1. A reduction gear comprising a reduction mechanism having an internal gear and an external gear, an output member for outputting a rotation reduced by the reduction mechanism, a fixed member fixed relative to the rotation of the output member, and a main bearing supporting the fixed member and the output member, wherein: The main bearing has an inner ring and an outer ring composed of plate-like members. At least one of the inner ring and the outer ring is provided separately from the fixed member and the output member and connected to the fixed member or the output member, and has an extension portion formed of a plate-shaped member, which constitutes another functional component of the reduction gear.

2. The reduction gear according to claim 1, characterized in that: The extension portion constitutes a movement limiting component that limits the movement of other components.

3. The deceleration device according to claim 2, characterized in that: The extending portion restricts the external gear from moving in the axial direction.

4. The reduction gear according to claim 1, wherein: The reduction gear is a flexural meshing reduction gear in which the external gear is flexurally deformed. The extending portion constitutes the external gear.

5. The reduction gear according to claim 1, characterized in that: The extending portion constitutes a pin member synchronized with the rotational component or the orbital component of the external gear.

6. The reduction gear according to any one of claims 1 to 5, characterized in that: The inner ring includes a first inner ring component and a second inner ring component that are separated from each other. One of the first inner ring member and the second inner ring member includes the extending portion, and the extending portion extends to a position farther from the rolling surface of the main bearing in the axial direction than the other of the first inner ring member and the second inner ring member.

7. The reduction gear according to claim 6, characterized in that: The extension portion is connected to one of the fixed member and the output member via a connecting member, and the extension portion extending to the opposite side of the rolling surface from the connecting member in the axial direction constitutes another functional component of the reduction gear transmission.

8. The reduction gear according to any one of claims 1 to 7, characterized in that: The main bearing has a structure capable of bearing radial loads and bidirectional axial loads by a single bearing.

9. The reduction gear according to any one of claims 1 to 8, characterized in that: The inner ring and the outer ring are formed of plate-shaped members bent by press forming.

10. The reduction gear according to any one of claims 1 to 9, characterized in that: The inner ring or the outer ring has a screw hole for screwing a connecting member for connecting the output member.

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