JP7462548B2 - Reduction gear - Google Patents

Description

The present invention relates to a reduction gear device.

Conventionally, there is a reduction gear device that includes 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).

JP 2020-133843 A

Conventional reduction gears with the above configuration have the problem of having a large number of parts. The present invention aims to provide a reduction gear that can reduce the number of parts.

The present invention relates to
A reduction gear transmission comprising: a reduction mechanism having an internal gear and an external gear; an output member that outputs rotation reduced by the reduction mechanism; a fixed member that is fixed with respect to rotation of the output member; and a main bearing that supports the fixed member and the output member ,
The main bearing has an inner ring and an outer ring formed of a plate member,
At least one of the inner ring and the outer ring is separate from the fixed member and the output member and connected to the fixed member or the output member, and the one of the inner ring and the outer ring has an extension portion formed by a plate member , and the extension portion constitutes another functional component of the reduction gear device.

The reduction gear device according to the present invention has the advantage of being able to reduce the number of parts.

1 is a cross-sectional view showing a reduction gear transmission according to a first embodiment of the present invention. FIG. 6 is a cross-sectional view showing a reduction gear transmission according to a second embodiment of the present invention. FIG. 11 is a cross-sectional view showing a reduction gear transmission according to a third embodiment of the present invention.

Each embodiment of the present invention will be described in detail below with reference to the drawings.

(Embodiment 1)
1 is a cross-sectional view showing a reduction gear according to a first embodiment of the present invention. In this embodiment, the direction along the rotation axis O1 of the vibrator shaft 10 is called the axial direction, the rotation direction around the rotation axis O1 is called the circumferential direction, and the direction perpendicular to the rotation axis O1 is called the radial direction. In addition, the side on which the output member 24 is arranged in the axial direction is called the output side, and the opposite side is called the anti-output side.

The reduction gear 1 is a flexible mesh type gear device, and includes a vibration exciter shaft 10, a vibration exciter 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, 27, a main bearing 28, and a stopper ring 16.

The vibrator shaft 10 is an input shaft that inputs the rotational motion. The vibrator shaft 10 is a hollow cylindrical shaft that rotates around the rotation axis O1, and has a vibrator 10A whose cross section perpendicular to the rotation axis O1 has a non-circular (e.g., elliptical) outer shape, and shaft portions 10B and 10C provided on both sides of the vibrator 10A in the axial direction. The elliptical shape does not have to be a geometrically strict ellipse, and includes an approximate ellipse. The shaft portions 10B and 10C are shafts whose cross section perpendicular to the rotation axis O1 has a circular outer shape. The material of the vibrator shaft 10 is not particularly limited, but in this embodiment, it is made of a metal such as steel.

The external gear 15 is a flexible cylindrical member with teeth on its outer circumference. There are no particular limitations on the material of the external gear 15, but in this embodiment, it is made of a metal such as steel.

The first internal gear 21 is an annular member with teeth on a portion of its inner circumference. The second internal gear 22 is an annular member with internal teeth on its inner circumference. The internal teeth of the first internal gear 21 and the internal teeth of the second internal gear 22 are aligned 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 output side, and the second internal gear 22 meshes with a portion of the external gear 15 on the output side. The material of the first internal gear 21 and the second internal gear 22 is not particularly limited, but in this embodiment, they are made of resin. The type of resin is not particularly limited, but in this embodiment, they are made of PEEK (Poly Ether Ether Ketone) material containing carbon fiber.

The first internal gear 21 further has an outer periphery whose one end and the other end in the axial direction extend toward the anti-output side and the output side, respectively. The outer periphery functions as a casing that covers the meshing portion between the external gear 15 and the first internal gear 21 and the second internal gear 22 from the radial outside.

The vibrator bearing 11 is, for example, a roller bearing, and is disposed between the vibrator 10A and the external gear 15. The vibrator bearing 11 does not have a dedicated outer ring and inner ring, and the inner periphery of the external gear 15 also serves as the outer ring of the vibrator bearing 11, and the outer periphery of the vibrator 10A also serves as the inner ring of the vibrator bearing 11. The vibrator bearing 11 may also have a separate outer ring and inner ring. The external gear 15 is supported rotatably relative to the vibrator 10A via the vibrator bearing 11. The material of the rolling elements of the vibrator bearing 11 is not particularly limited, but in this embodiment, it is made of a metal such as a steel material.

The stopper ring 16 is disposed on the anti-output side of the external gear 15 and the vibration exciter bearing 11, and prevents the external gear 15 and the vibration exciter bearing 11 from moving toward the anti-output side. There are no particular limitations on the material of the stopper ring 16, but in this embodiment, it is made of a metal such as steel.

The inner ring 28i1 of the main bearing 28 has an extension 28e located on the output side of the external gear 15 and the vibration exciter bearing 11. The extension 28e functions as a movement restriction part that restricts the movement of the external gear 15 and the vibration exciter bearing 11 toward the output side.

The output member 24 is located on the output side of the reduction gear 1, and outputs reduced rotation by connecting with the second internal gear 22. The output member 24 may be annular with a hole in the center so as not to block the hollow portion of the vibration exciter shaft 10. There are no particular limitations on the material of the output member 24, but in this embodiment, it is made of resin. There are no particular limitations on the type of resin, but in this embodiment, it is made of POM (Polyoxymethylene, Polyacetal) material containing carbon fiber.

The vibration exciter 10A, vibration exciter bearing 11, external gear 15, first internal gear 21, and second internal gear 22 constitute a reduction mechanism. The first internal gear 21 is directly or indirectly connected to an external support member 81 that supports the reduction gear device 1. The reduction mechanism reduces the speed of the rotation input to the vibration exciter 10A and outputs the reduced rotation to the second internal gear 22. The second internal gear 22 is connected to an external mating member 82 together with an output member 24. The second internal gear 22 and the output member 24 output the rotation reduced by the reduction mechanism to the mating member 82.

The cover member 25 is located on the anti-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 anti-output side. The cover member 25 is connected to the first internal gear 21. There are no particular limitations on the material of the cover member 25, but in this embodiment, it is made of resin. There are no particular limitations on the type of resin, but in this embodiment, it is made of POM material containing carbon fiber.

Bearings 26 and 27 are, for example, ball bearings, but the type of bearing is not particularly limited. Bearing 26 is interposed between cover member 25 and vibrator shaft 10, and supports them so that they can rotate relative to one another. Bearing 27 is interposed between output member 24 and vibrator shaft 10, and supports them so that they can rotate relative to one another.

The main bearing 28 is interposed between the first internal gear 21, the second internal gear 22, and the output member 24, and supports them so that they can rotate relatively. The main bearing 28 is a cross roller bearing, and can receive radial loads and thrust loads in both directions with a single bearing. In addition, the main bearing 28 may be configured to receive moment loads with a single bearing. A single bearing means that when the bearing is taken out alone, it cannot be divided into multiple parts that each function as a bearing. Note that the main bearing 28 is not limited to a cross roller bearing, and other bearings that can receive radial loads and thrust loads in both directions with a single bearing, such as a four-point contact ball bearing, may be applied. In addition, the main bearing is not limited to a bearing that can receive radial loads and thrust loads in both directions with a single bearing, and various bearings can be applied, and it may be configured, for example, by a pair of bearings. In this case, the present invention may be applied to both of the pair of bearings, or to only one of them. Furthermore, it may be a bearing that cannot receive radial loads and some of the thrust loads in both directions.

<Deceleration operation>
When a rotational motion is input from the outside to the vibration exciter shaft 10, the rotational motion of the vibration exciter 10A is transmitted to the external gear 15. At this time, the external gear 15 is restricted to a shape that conforms to the outer circumferential surface of the vibration exciter 10A, and is bent into an elliptical shape having a major axis portion and a minor axis portion when viewed from the axial direction. Furthermore, the external gear 15 is meshed with the fixed first internal gear 21 at the major axis portion. Therefore, the external gear 15 does not rotate at the same rotational speed as the vibration exciter 10A, and the vibration exciter 10A rotates relatively inside the external gear 15. Then, with this relative rotation, the external gear 15 is bent and deformed so that the major axis position and the minor axis position move in the circumferential direction. The period of this deformation is proportional to the rotation period of the vibration exciter shaft 10.

When the external gear 15 flexes and deforms, its major axis position moves, 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, then the meshing teeth between the external gear 15 and the first internal gear 21 shift each time the meshing position rotates around one revolution, causing the external gear 15 to rotate (spin on its axis). With the above number of teeth, the rotational motion of the vibration exciter shaft 10 is decelerated at a reduction ratio of 100:2 and transmitted to the external gear 15.

On the other hand, since the external gear 15 is also meshed with the other second internal gear 22, the meshing position between the external gear 15 and the second internal gear 22 also changes in the rotational direction due to the rotation of the vibration exciter shaft 10. On the other hand, since the number of teeth of the second internal gear 22 and the number of teeth of the external gear 15 are the same, the external gear 15 and the second internal gear 22 do not rotate relative to each other, and the rotational motion of the external gear 15 is transmitted to the second internal gear 22 at a reduction ratio of 1:1. As a result, the rotational motion of the vibration exciter shaft 10 is decelerated at a reduction ratio of 100:2 and transmitted to the second internal gear 22 and the output member 24. This decelerated rotational motion is then output from the output member 24 to the mating member 82.

If a radial load or thrust load in both directions is applied between the external support member 81 and the mating member 82 during deceleration operation of the reduction gear 1, the main bearing 28 will receive these loads, allowing the reduction gear 1 to continue deceleration operation without hindrance. In addition, if a moment load is applied between the external support member 81 and the mating member 82 during deceleration operation of the reduction gear 1, the main bearing 28 may receive the moment load, allowing the reduction gear 1 to continue the deceleration operation without hindrance.

<Inner and outer rings of main bearing>
The main bearing 28 has inner rings 28i1 and 28i2 made of plate members, outer rings 28o1 and 28o2 made of plate members, and roller-shaped rolling elements 28t. If the main bearing 28 is a four-point contact ball bearing, the rolling elements 28t are ball-shaped. The plate members may be made of metal such as steel.

Each of the inner rings 28i1, 28i2 and the outer rings 28o1, 28o2 is formed by bending a plate member by press molding, and at least the plate-like portion constituting the rolling surface (also called the raceway surface) of the cross-sectional shape in FIG. 1 has a ring-shaped form that is continuous in the circumferential direction. The outer rings 28o1, 28o2 are arranged on the output side and the anti-output side, respectively, and are composed of two members that are divided from each other, and each includes a rolling surface on which the rolling element 28t rolls. Similarly, the inner rings 28i1, 28i2 are arranged on the output side and the anti-output side, respectively, and are composed of two members that are divided from each other, and each includes a rolling surface on which the rolling element 28t rolls. A rolling element (roller) having a rotation axis x1 rolls on the rolling surface of the inner ring 28i1 and the outer ring 28o2, and a rolling element (roller) having a rotation axis x2 rolls on the rolling surface of the inner ring 28i2 and the outer ring 28o1. The inner ring 28i1 corresponds to an example of a first inner ring member according to the present invention, and the inner ring 28i2 corresponds to an example of a second inner ring member according to the present invention.

By constructing the inner rings 28i1, 28i2 and the outer rings 28o1, 28o2 from plate members, the weight and cost of the main bearing 28 can be reduced.

The outer rings 28o1 and 28o2 further have a flange portion 28f1 that extends radially outward, and a connecting hole (e.g., a through hole) h28o provided in the flange portion 28f1. The flange portion 28f1 may be provided continuously around the entire circumference in the circumferential direction, or may be provided at multiple locations in the circumferential direction. The connecting hole h28o is provided at multiple locations in the circumferential direction.

The first internal gear 21 has a flange portion 21f that is positioned so as to overlap the flange portion 28f1 when viewed from the axial direction, and a connection hole (e.g., a screw hole) h21 provided in the flange portion 21f. The flange portion 21f may be provided continuously around the entire circumference in the circumferential direction, or may be provided at multiple locations in the circumferential direction. The connection hole h21 is provided at multiple locations in the circumferential direction.

The flange portion 28f1 of the outer rings 28o1 and 28o2 and the flange portion 21f of the first internal gear 21 are connected by a connecting member B1 such as a bolt through the connecting holes h28o and h21. Furthermore, the flange portions 28f1 and 21f can be connected to an external support member 81 by a connecting member B2 such as a bolt through the connecting holes h28o and h21.

The inner rings 28i1 and 28i2 further have a flange portion 28f2 that extends radially inward, and a connection hole (e.g., a through hole) h28i provided in the flange portion 28f2. The flange portion 28f2 may be provided continuously around the entire circumference in the circumferential direction, or may be provided at multiple locations in the circumferential direction. The connection hole h28i is provided at multiple locations in the circumferential direction.

The second internal gear 22 has connection holes (e.g., screw holes) h22 at multiple locations in the circumferential direction.

The output member 24 has connection holes (e.g., through holes) h24a, h24b at multiple locations in the circumferential direction.

The output member 24, the flange portion 28f2 of the inner rings 28i1 and 28i2, and the second internal gear 22 are connected by a connecting member B3 such as a bolt through the connecting holes h24a, h28i, and h22 of each other. Furthermore, the external mating member 82 can be connected by a connecting member B4 such as a bolt through the connecting holes h24b, h28i, and h22 of the output member 24, the flange portion 28f2, and the second internal gear 22.

The inner ring 28i1 further has a disk-shaped (disk-shaped with a through hole in the center, i.e., annular) extension 28e that extends radially inward and continues in the circumferential direction. The inner ring 28i1 with the extension 28e is located further inward in the axial direction of the device than the other inner ring 28i2. "Inward of the device" means closer to the center of the reduction mechanism (the center of the meshing portion between the external gear 15 and the first internal gear 21 and second internal gear 22) in the axial direction.

As described above, the extension 28e constitutes a functional part other than a bearing, and specifically functions as a movement restriction part that restricts the movement of the external gear 15 and the vibration exciter bearing 11 toward the output side.

Plate members are easy to obtain high thickness accuracy and desired surface characteristics. Therefore, the extension portion 28e of the inner ring 28i1, which is made of a plate member, can have high thickness accuracy and surface characteristics suitable for a movement restriction part without having to undergo costly processing.

Furthermore, the extension portion 28e extends to a position where it overlaps with the outer ring of the bearing 27 when viewed from the axial direction, and can contact the entire side surface of the retainer of the vibrator bearing 11. This contact can stably restrict the movement of the vibrator bearing 11. In this way, it is difficult to realize a configuration that contacts the entire side surface of the retainer to restrict the movement of the vibrator bearing 11 other than by arranging an independent stopper member or by providing an extension portion on one or both of the inner rings 28i1 and 28i2. For example, if an attempt is made to provide a similar movement restriction component by extending a part of the output member 24 instead of the extension portion 28e, the following difficulties arise. That is, the outer ring of the bearing 27 is fitted into the inner periphery of the output member 24 from the anti-output side, and is positioned by abutting against the protruding portion 24a that protrudes radially inward of the output member 24. Therefore, if a portion of the output member 24 were to extend to the vicinity of the vibrator bearing 11 instead of the extension portion 28e, it would be difficult to assemble the bearing 27 and the output member 24. However, in the first embodiment, the extension portion 28e is provided on the inner ring 28i2, so that a portion of the inner ring 28i2 functions as a movement restriction part, and therefore the inner ring 28i2 having the movement restriction part (extension portion 28e) can be assembled into the device without the above-mentioned difficulties.

In the first embodiment, an example is shown in which the outer ring of the main bearing 28 is composed of two members (outer rings 28o1 and 28o2) and the inner ring is composed of two members (inner rings 28i1 and 28i2). However, the outer ring may be composed of a single plate member by press molding or the like, and the inner ring may be composed of a single plate member by press molding or the like. In addition, in the configuration of the first embodiment, an extension part extending to the opposite output side may be provided following one end of either one of the outer rings 28o1 and 28o2. The extension part may function as a casing that covers the radial outside of the meshing part between the external gear 15 and the first internal gear 21 and the second internal gear 22. The outer ring having such an extension part may be the outer ring 28o1 located axially inward of the device, and in this case, the extension part can be made small in size and can function as a casing without being processed into a complex shape.

As described above, the reduction gear 1 of the first embodiment includes a reduction mechanism having the first internal gear 21, the second internal gear 22, and the 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 has inner rings 28i1, 28i2 and outer rings 28o1, 28o2 made of plate members, and the inner ring 28i1 has an extension portion 28e, which constitutes another functional component of the reduction gear 1. Therefore, the inner ring 28i1 and the other functional components are integrated, and the number of components can be reduced. In addition, since the inner rings 28i1, 28i2 and the outer rings 28o1, 28o2 of the main bearing 28 are made of plate members, the main bearing 28 is lighter than a main bearing having a block-shaped inner ring and outer ring, and thus the reduction gear 1 can be lighter.

Specifically, the extension 28e functions as a movement restriction component that restricts the movement of other components. Because the inner ring 28i1 is made of a plate member, the extension 28e has high thickness accuracy and can easily obtain the desired surface characteristics. Therefore, the extension 28e functions well as a movement restriction component.

More specifically, the extension 28e restricts the movement of the external gear 15 toward the output side. The extension 28e requires surface characteristics that can withstand sliding because the external gear 15 slides against it to restrict the movement of the external gear 15, but because the inner ring 28i1 is made of a plate member, such surface characteristics can be easily obtained.

Furthermore, according to the reduction gear 1 of the first embodiment, the inner rings 28i1, 28i2 are composed of two members separated from each other, and one of the inner rings 28i2 has an extension portion 28e. By having the inner rings 28i1, 28i2 composed of two members, the processing of the rolling surface of the rolling element 28t is facilitated, and since one of the inner rings 28i1 has an extension portion 28e, molding of the extension portion 28e is facilitated and assembly of the extension portion 28e is facilitated compared to the case where an extension portion is provided on both inner rings 28i1 and two extension portions are used overlapping each other.

Furthermore, according to the reduction gear device 1 of the first embodiment, the extension portion 28e is provided on the inner ring 28i1, which is disposed on the inside in the axial direction of the device, of the inner rings 28i1 and 28i2. Therefore, the extension portion 28e can be arranged as a functional part of the reduction gear mechanism with a small size and without requiring a complex shape that would avoid other parts.

Furthermore, according to the reduction gear 1 of embodiment 1, the main bearing 28 is configured to be able to receive radial loads and thrust loads in both directions by a single bearing. Therefore, compared to a configuration having two main bearings arranged at different positions in the axial direction, the total number of parts of the reduction gear 1 can be reduced. In addition, since a bearing that receives such loads can be easily constructed from two inner rings 28i1, 28i2 that are separated from each other and two outer rings 28o1, 28o2 that are separated from each other, in addition to the above effect obtained by the configuration in which the inner rings 28i1, 28i2 are separated from each other, the effect of making it easy to construct a bearing that receives the above loads is achieved by having the inner rings 28i1, 28i2 composed of two members that are separated from each other.

Furthermore, according to the reduction gear transmission 1 of embodiment 1, the inner rings 28i1, 28i2 and the outer rings 28o1, 28o2 are made of plate members bent by press molding. Therefore, the manufacturing costs of the inner rings 28i1, 28i2 and the outer rings 28o1, 28o2 can be reduced, and the parts costs of the reduction gear transmission 1 can be reduced.

(Embodiment 2)
2 is a cross-sectional view showing a reduction gear according to a second embodiment of the present invention. In the second embodiment, the direction along the rotation axis O1 of the eccentric body shaft 31 is called the axial direction, the rotation direction about the rotation axis O1 is called the circumferential direction, and the direction perpendicular to the rotation axis O1 is called the radial direction. In addition, the side where the carrier body 41 is arranged (the carrier body 41 side as seen from the external gears 34, 36) that outputs the rotational motion reduced in the axial direction is called the output side, and the opposite side is called the anti-output side.

The reduction gear 1A of the second embodiment is an eccentric oscillating type reduction gear in which the external gears 34, 36 eccentrically oscillate, and includes an eccentric shaft 31 having two eccentric bodies 31b, 31c, two external gears 34, 36, an internal gear 38 meshing with the external gears 34, 36, eccentric body bearings 51, 52, an inner pin 55ep engaging with the external gears 34, 36, a carrier body 41 connected to the inner pin 55ep, a cover member 46 covering the portion where the external gears 34, 36 oscillate from the non-output side, and a main bearing 55 interposed between the carrier body 41 and the internal gear 38. The carrier body 41 corresponds to an example of an output member according to the present invention. The inner pin 55ep corresponds to an example of a pin member according to the present invention.

The reduction gear 1A further includes a stopper ring 44 arranged between the external gear 34 and the cover member 46, a stopper ring 45 arranged between the two external gears 34, 36, a collar 48 attached to the shaft portion 31a1 of the eccentric shaft 31, a seal 47 located between the collar 48 and the cover member 46, and high-speed bearings 53, 54 that support the eccentric shaft 31.

The eccentric shaft 31 has shaft portions 31a1, 31a2, and 31a3 where the rotation axis O1 overlaps with the central axis, and eccentric bodies 31b and 31c that are provided eccentrically from the rotation axis O1. The eccentric bodies 31b and 31c have a circular cross section perpendicular to the rotation axis O1, and rotate eccentrically in different phases as the eccentric shaft 31 rotates.

The external gear 34 is mounted on the eccentric body 31b via an eccentric body bearing 51, and oscillates as the eccentric body shaft 31 rotates. The other external gear 36 is mounted on the eccentric body 31c via an eccentric body bearing 52, and oscillates in a different phase from the external gear 34 as the eccentric body shaft 31 rotates. The external gear 34 is provided with an inner pin hole 34h through which the inner pin 55ep passes. Similarly, the external gear 36 is provided with an inner pin hole 36h through which the inner pin 55ep passes.

The inner pin 55ep and the inner pin holes 34h and 36h may be provided one each, or multiples may be provided at multiple locations in the circumferential direction.

The inner pin 55ep contacts the inner peripheral surfaces of the inner pin holes 34h, 36h via the sleeve 49, and moves (including stationary) in synchronization with the movement (rotation) of the external gears 34, 36. Specifically, the carrier body 41 rotates by revolving in synchronization with the rotation of the external gears 34, 36, or when the rotation of the external gears 34, 36 is constrained, the revolution is constrained and the rotation of the carrier body 41 is also constrained.

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

The high-speed bearings 53 and 54 are not limited to a particular type of bearing, but may be ball bearings, for example. One of the high-speed bearings, 53, is interposed between the cover member 46 and the shaft portion 31a2 of the eccentric shaft 31, and supports them so that they can rotate relative to one another. The other high-speed bearing, 54, is interposed between the carrier body 41 and the shaft portion 31a3 of the eccentric shaft 31, and supports them so that they can rotate relative to one another.

The main bearing 55 supports the internal gear 38 and the carrier body 41 so that they can rotate relative to one another. The main bearing 55 is a cross roller bearing, and can receive radial loads and thrust loads in both directions with a single bearing. In addition, the main bearing 55 may be configured to receive moment loads with a single bearing. Note that the main bearing 55 is not limited to a cross roller bearing, and other bearings that can receive radial loads and thrust loads in both directions with a single bearing, such as a four-point contact ball bearing, may also be used.

<Deceleration operation>
In the reduction gear transmission 1A configured as described above, the internal gear 38 is directly or indirectly connected to an external support member 81 by a connecting member B13 such as a bolt, and the carrier body 41 is directly or indirectly connected to an external mating member 82 by a connecting member B12 such as a bolt. When a rotational motion is input to the eccentric body shaft 31 from the outside, the reduction gear transmission 1A decelerates the input rotation and outputs the decelerated rotation from the carrier body 41 to the mating member 82.

In detail, when the eccentric shaft 31 rotates, the eccentric bodies 31b and 31c rotate eccentrically, and one external gear 34 and the other external gear 36 are oscillated with a phase difference of 180 degrees. The presence of two external gears 34 and 36 increases the transmission capacity and maintains the strength, and further maintains the rotational balance of the reduction gear 1A. The external gears 34 and 36 are in inscribed mesh with the internal gear 38, which is connected to the support member 81. Therefore, the external gears 34 and 36 rotate (rotate) relative to the internal gear 38 by the difference in the number of teeth every time the eccentric shaft 31 rotates once. The rotation 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 decelerated at a reduction ratio of (difference in the number of teeth between the internal gear 38 and the external gears 34 and 36)/(common number of teeth between the external gear 34 and the external gear 36) and transmitted to the carrier body 41. The decelerated rotation is then output from the carrier body 41 to the mating member 82.

If a radial load or thrust load in both directions is applied between the external support member 81 and the mating member 82 during deceleration operation of the reduction gear 1A, the main bearing 55 will receive these loads, allowing the reduction gear 1A to continue deceleration operation without hindrance. Also, if a moment load is applied between the external support member 81 and the mating member 82 during deceleration operation of the reduction gear 1A, the main bearing 55 may receive the moment load, allowing the above-mentioned deceleration operation to continue without hindrance.

The reduction gear 1A may be used such that the carrier body 41 is directly or indirectly connected to a support member, the internal gear 38 is directly or indirectly connected to a mating member, and the reduced rotation is output to the mating 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 an output member according to the present invention.

<Inner and outer rings of main bearing>
The main bearing 55 has inner rings 55i1 and 55i2 made of plate members, outer rings 55o1 and 55o2 made of plate members, and roller-shaped rolling elements 55t. If the main bearing 55 is a four-point contact ball bearing, the rolling elements 55t are ball-shaped.

Each of the inner rings 55i1, 55i2 and the outer rings 55o1, 55o2 is formed by bending a plate member by press molding, and at least the plate-like portion constituting the rolling surface (also called the raceway surface) in the cross-sectional shape of FIG. 1 has a ring-shaped form that is continuous in the circumferential direction. The outer rings 55o1, 55o2 are composed of two members arranged on the output side and the opposite output side, respectively, and each includes a rolling surface on which the rolling element 55t rolls. Similarly, the inner rings 55i1, 55i2 are composed of two members arranged on the output side and the opposite output side, respectively, and each includes a rolling surface on which the rolling element 55t rolls. A rolling element (roller) having a rotation axis x1 rolls on the rolling surface of the inner ring 55i1 and the outer ring 55o2, and a rolling element (roller) having a rotation axis x2 rolls on the rolling surface of the inner ring 55i2 and the outer ring 55o1.

By constructing the inner rings 55i1, 55i2 and the outer rings 55o1, 55o2 from plate members, the weight and cost of the main bearing 55 can be reduced.

The outer rings 55o1 and 55o2 further have a flange portion 55f1 that extends radially outward, and a connecting hole (e.g., a through hole) h55o provided in the flange portion 55f1. The flange portion 55f1 may be provided continuously around the entire circumference in the circumferential direction, or may be provided at multiple locations in the circumferential direction. The connecting hole h55o is provided at multiple locations in the circumferential direction.

The internal gear 38 has connection holes (e.g., screw holes) h38 at multiple locations in the circumferential direction.

The flange portion 55f1 of the outer rings 55o1 and 55o2 and the internal gear 38 are connected by a connecting member B11 such as a bolt through the connecting holes h55o and h38. The flange portion 55f1 may also be used to connect to an external support member. In this case, the support member is connected by a connecting member such as a bolt through the connecting holes h55o and h38.

The inner rings 55i1 and 55i2 further have a flange portion 55f2 that extends radially inward, and a connection hole (e.g., a through hole) h55i provided in the flange portion 55f2. The flange portion 55f2 may be provided continuously around the entire circumference in the circumferential direction, or may be provided at multiple locations in the circumferential direction. The connection hole h55i is provided at multiple locations in the circumferential direction.

The carrier body 41 has connection holes (e.g., through holes) h41 at multiple locations in the circumferential direction.

The flange portion 55f2 of the inner rings 55i1 and 55i2 and the carrier body 41 are connected by a connecting member B12 such as a bolt through the connecting holes h55i and h41. Furthermore, the external mating member 82 can be connected by a connecting member B12 such as a bolt through the connecting holes h55i and h41 of the flange portion 55f2 and the carrier body 41.

The inner ring 55i1 further has an extension 55e1 extending radially inward. The inner ring 55i1 having the extension 55e1 is located closer to the inside of the device (inward in the axial direction) than the other inner ring 55i2. Furthermore, the extension 55e1 has a hollow inner pin 55ep protruding in a pin-like shape on the opposite output side. The inner pin 55ep is formed by deep drawing a plate material. The extension 55e1 may be a circular plate (a circular plate with a hole in the center) that is continuous in the circumferential direction, or may have a notch in a part in the circumferential direction. The inner pin 55ep is provided at one or more points in the circumferential direction. The inner pin 55ep passes through a through hole in the carrier body 41 from the output side to the opposite output side, and protrudes toward the external gears 34 and 36.

The other inner ring 55i2 similarly has an extension 55e2 that extends radially inward. The extension 55e2 may be a circular plate that continues in the circumferential direction (a circular plate with a hole in the center), or may have a notch in one part in the circumferential direction. The extension 55e2 closes the opening at the base of the inner pin 55ep.

As described above, the reduction gear 1A of 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 the rotation reduced by the reduction mechanism, and a main bearing 55 that supports the carrier body 41. Furthermore, the main bearing 55 has inner rings 55i1 and 55i2 and outer rings 55o1 and 55o2 made of plate members, and the inner ring 55i1 has an extension portion 55e1 (including an inner pin 55ep), which constitutes another functional part (inner pin 55ep) of the reduction gear 1. Therefore, the inner ring 55i1 and the other functional parts are integrated, and the number of parts can be reduced. In addition, since the inner rings 55i1 and 55i2 and the outer rings 55o1 and 55o2 of the main bearing 55 are made of plate members, the main bearing 55 is lighter than a main bearing having a block-shaped inner ring and outer ring, and the reduction gear 1A can be lighter.

Specifically, the extension 55e1 of the inner ring 55i1 constitutes an inner pin 55ep that is synchronized with the rotational components of the external gears 34 and 36. Therefore, one or more inner pins 55ep can be integrated, simplifying the assembly process of the inner pins 55ep.

In the reduction gear 1A of embodiment 2, as in embodiment 1, the inner rings 55i1, 55i2 are composed of two separate members, and the main bearing 55 receives radial loads and thrust loads in both directions through a single bearing. In addition, the inner rings 55i1, 55i2 and the outer rings 55o1, 55o2 are composed of plate members that are bent by press molding. Therefore, the above-mentioned effects obtained by the same configuration as in embodiment 1 are similarly achieved.

(Embodiment 3)
3 is a cross-sectional view showing a reduction gear according to embodiment 3. The third embodiment is a partial modification of the first embodiment, and the same configurations as those in the first embodiment are given the same reference numerals and detailed description is omitted. The reduction gear 1B of the third embodiment is a so-called top hat type flexible mesh gear device, and its reduction mechanism has an external gear 28e2 having a flange portion 28f3, one internal gear 21B, and a vibration exciter bearing 11B corresponding to the one internal gear 21B. The reduction gear 1B of the third embodiment also has a main bearing 28B in which an extension portion of the inner ring 28i1B functions as the external gear 28e2.

The internal gear 21B has the same configuration as the first internal gear 21 in embodiment 1. The reduction gear 1B in embodiment 3 does not have a second internal gear.

The external gear 28e2 has a cylindrical portion and a flange portion 28f3 that extends radially outward from one end of the cylindrical portion, and is a metal member that has flexibility at least in the cylindrical portion. The external teeth G1 are provided in the area of the cylindrical portion that faces the internal gear 21B (its internal teeth portion).

The vibration exciter bearing 11B is interposed between the vibration exciter 10A and the external gear 28e2, and supports the vibration exciter 10A and the external gear 28e2 so that they can rotate freely relative to each other. The vibration exciter bearing 11B is provided at a position corresponding to the meshing portion between the external gear 28e2 and the internal gear 21B (diametrically inward of the meshing portion).

In addition to the same configuration as in embodiment 1, the vibrator shaft 10 has 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.

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

The main bearing 28B is interposed between the internal gear 21B and 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, as well as the internal gear 21B and the external gear 28e2, so that they can rotate freely relative to each other. The main bearing 28B is configured in the same way as the main bearing 28B of embodiment 1, except that the extension portion of the inner ring 28i1B is different.

<Deceleration operation>
When a rotational motion is input to the vibration exciter shaft 10 from the outside, the rotational motion of the vibration exciter 10A is transmitted to the external gear 28e2. At this time, the external gear 28e2's external teeth are regulated to a shape that conforms to the outer circumferential surface of the vibration exciter 10A, and is bent into an elliptical shape having a major axis portion and a minor axis portion when viewed from the axial direction. Furthermore, the external gear 28e2 is meshed with the fixed internal gear 21B at the major axis portion. For this reason, the external gear 28e2 does not rotate at the same rotational speed as the vibration exciter 10A, and the vibration exciter 10A rotates relatively inside the external gear 28e2, and the external gear 28e2 is bent and deformed so that the major axis position and the minor axis position move in the circumferential direction. Then, as the major axis position moves, the meshing position of the external gear 28e2 and the internal gear 21B changes in the rotational direction. Here, if the number of teeth of the external gear 28e2 is 100 and the number of teeth of the internal gear 21B is 102, the meshing teeth of the external gear 28e2 and the internal gear 21B shift each time the meshing position rotates around once, causing the external gear 28e2 to rotate (spin). With the above number of teeth, the rotational motion of the vibration exciter shaft 10 is reduced at a reduction ratio of 100:2 and transmitted to the external gear 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 mating member 82.

If a radial load or thrust load in both directions is applied between the external support member 81 and the mating member 82 during deceleration operation of the reduction gear 1B, the main bearing 28B will receive these loads, allowing the reduction gear 1B to continue deceleration operation without hindrance. Also, if a moment load is applied between the external support member 81 and the mating member 82 during deceleration operation of the reduction gear 1B, the main bearing 28B may receive the moment load, allowing the reduction gear 1B to continue the deceleration operation without hindrance.

<Inner and outer rings of main bearing>
The main bearing 28B has inner rings 28i1B and 28i2 made up of two members and outer rings 28o1 and 28o2 made up of two members, and further, the inner ring 28i1B located inside the device has an extension part (external gear 28e2) that constitutes another functional part. The extension part is a cylindrical part extending in the axial direction, and constitutes the top hat type external gear 28e2 as described above.

Furthermore, the flange portion 28f3 of the inner ring 28i1B is provided with a screw hole h28B with a screw formed by tapping or the like, and is screwed with a connecting member B6, B7 such as a bolt. The output member 24 and the inner rings 28i1B, 28i2 are connected by a connecting member B6 such as a bolt through the connecting holes h24a, h28i and the screw hole h28B. With this configuration, nuts are not required to connect the inner rings 28i1B, 28i2 and the output member 24, and the number of parts can be further reduced. Furthermore, the output member 24 and the external mating member 82 are connected by a connecting member B7 such as a bolt through the connecting holes h24b, h28i and the screw hole h28B. With this configuration, nuts are not required to connect the mating member 82 and the output member 24, and the number of parts can be further reduced.

The reduction gear 1B can also be used by connecting the inner rings 28i1B, 28i2 and the external gear 28e2 to an external support member, and connecting the outer rings 28o1, 28o2 and the internal gear 21B to an external mating member. In this case, the rotational motion input to the vibration exciter shaft 10 is decelerated and transmitted to the internal gear 21B, and is output from the internal gear 21B to the external mating member. In this case, the internal gear 21B functions as an output member that outputs the decelerated rotation.

Furthermore, in a configuration in which the internal gear 21B functions as an output member, the connecting hole h28o of the outer ring 28o2 may be configured as a screw hole with a screw formed therein by a tap or the like, while the connecting hole h21 of the internal gear 21B may be configured as a through hole. Then, a bolt may be passed from the connecting hole (e.g., a through hole) h21 of the internal gear 21B through the connecting hole h28o of the outer rings 28o1 and 28o2, and screwed into the connecting hole h28o (threaded hole) of one of the outer rings 28o2, thereby connecting the internal gear 21B, which is the output member, to the outer rings 28o1 and 28o2.

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 has inner rings 28i1B, 28i2 and outer rings 28o1, 28o2 that are made of plate members, and the inner ring 28i1B has an extension portion (28e2), which constitutes other functional parts. Therefore, the inner ring 28i1B and other functional parts are integrated, and the number of parts can be reduced. In addition, since the inner rings 28i1B, 28i2 and the outer rings 28o1, 28o2 of the main bearing 28B are made of plate members, the main bearing 28B is lighter than a main bearing having a block-shaped inner ring and outer ring, and thus the reduction gear 1B can be lighter.

Specifically, the extension (28e2) of the inner ring 28i1B constitutes the external gear 28e2 that undergoes flexural deformation. The extension of the inner ring 28i1B, which is a plate member, makes it easier to obtain the flexural deformation characteristics of the external gear 28e2.

Furthermore, according to the reduction gear 1B of the third embodiment, the inner ring 28i1B has a screw hole h28B that screws into the connecting members B6, B7 such as bolts. Therefore, when connecting the inner rings 28i1B, 28i2, or connecting the inner rings 28i1B, 28i2 to other members (output member 24, external gear 28e2, etc.), if there is no member that functions as a nut in the location, nuts are not required, and the number of parts can be reduced.

The above describes each embodiment of the present invention. However, the present invention is not limited to the above embodiments. For example, in the above embodiments, a so-called cylindrical flexible mesh gear device, a center crank type eccentric oscillating reduction gear device, and a so-called top hat type flexible mesh gear device are shown. However, the present invention can be applied to various types of reduction gear devices, such as a so-called cup type flexible mesh gear device, a so-called distribution type eccentric oscillating reduction gear device in which two or more eccentric shafts having eccentric bodies are arranged offset from the axis of the reduction gear device, or a simple planetary gear device. When the present invention is applied to a simple planetary gear device, a pin member may be formed by an extension of the inner ring as in embodiment 2, and the pin member may be configured to synchronize with the revolution component of the planetary gear (external gear). Other details shown in the embodiments can be appropriately changed within the scope of the invention.

Reference Signs List 1, 1A, 1B Reduction gear 10 Vibrator shaft 10A Vibrator 11 Vibrator bearing 15 External gear 16 Stopper ring 21 First internal gear 22 Second internal gear 24 Output member 28, 28B Main bearing 28i1, 28i2, 28i1B, 55i1, 55i2 Inner ring 28o1, 28o2, 55o1, 55o2 Outer ring 28e Extension portion (restriction part)
28e2 External gear (extension portion)
31 Eccentric body shaft 31b, 31c Eccentric body 34, 36 External gear 38 Internal gear 41 Carrier body (output member)
55 Main bearing 55e1, 55e2 Extension portion 55ep Inner pin (pin member, extension portion)

Claims (10)

A reduction gear transmission comprising: a reduction mechanism having an internal gear and an external gear; an output member that outputs rotation reduced by the reduction mechanism; a fixed member that is fixed with respect to rotation of the output member; and a main bearing that supports the fixed member and the output member ,
The main bearing has an inner ring and an outer ring formed of a plate member,
At least one of the inner ring and the outer ring is separate from the fixed member and the output member and connected to the fixed member or the output member, and the one of the inner ring and the outer ring has an extension portion formed by a plate member , and the extension portion constitutes another functional component of the reduction gear device. The extension portion constitutes a movement restriction component that restricts movement of another member.
The reduction gear according to claim 1. The extension portion restricts axial movement of the external gear.
The reduction gear according to claim 2. The reduction gear is a flexible mesh type reduction gear in which the external gear is flexibly deformed,
The extension portion constitutes the external gear.
The reduction gear according to claim 1. The extension portion constitutes a pin member that is synchronized with a rotation component or a revolution component of the external gear.
The reduction gear according to claim 1. The inner ring has a first inner ring member and a second inner ring member separated from each other,
one of the first inner ring member and the second inner ring member has the extension portion extending to a position axially farther from the rolling surface of the main bearing than the other of the first inner ring member and the second inner ring member;
The reduction gear transmission according to any one of claims 1 to 5. the extension portion is connected to one of the fixed member and the output member by a connecting member, and the extension portion extending to an opposite side of the rolling surface in the axial direction from the connecting member constitutes another functional component of the reduction gear device .
The reduction gear according to claim 6. The main bearing is configured to be able to receive radial loads and thrust loads in both directions by a single bearing.
The reduction gear transmission according to any one of claims 1 to 7. The inner ring and the outer ring are formed of plate members bent by press molding.
The reduction gear transmission according to any one of claims 1 to 8. The inner ring or the outer ring has a screw hole into which a connecting member for connecting to the output member is screwed.
The reduction gear transmission according to any one of claims 1 to 9.

Images