TWI842431B - Fluctuation generator of oscillating gear device and oscillating gear device - Google Patents

Abstract

The present invention provides a ripple generator of a ripple gear device and a ripple gear device that can prevent deflection and reduce friction loss. The ripple generator 4 of the ripple gear device 1 includes: a non-circular cam member 5; a plurality of rollers 6 arranged on the outer circumference of the cam member 5; and a roller retainer 7 that retains the rollers 6. The roller retainer 7 includes a first roller retainer 7A, which is shaped into a flexible cylindrical shape having a plurality of opening portions A1 spaced apart in the circumferential direction. When mounted on the cam member 5 together with the roller 6, at least on the long axis side of the cam member 5, the roller 6 is retained from the outer peripheral side of the wave generator 4 by a mounting portion 72a formed between the opening portions A1, and the roller 6 is rotatably exposed to the outer peripheral side of the wave generator 4 by the opening portion A1.

Description

Fluctuation generator of oscillating gear device and oscillating gear device

The present invention relates to a fluctuation generator of a fluctuation gear device and a fluctuation gear device.

In a pulsating gear device, for the purpose of improving durability, a device is known that uses a roller bearing as a bearing disposed between a cam member and an outer gear (for example, refer to Patent Document 1). On the other hand, in a pulsating gear device, when a roller is used, the roller has play in a portion other than the long shaft portion of the cam member, so the roller sometimes deflects (roller tilts). If the roller rolls to the long shaft portion of the cam member while maintaining a deflected state, friction loss will occur in the pulsating gear device, and in the worst case, the roller may not rotate normally. Therefore, in previous oscillating gear devices, in addition to introducing a roller retainer, a roller pressing member such as a cylindrical spring is introduced between the cam member and the roller to press the axial ends of the roller toward the outer circumference to prevent the occurrence of deflection (for example, refer to Patent Document 2).

[Prior art literature]

[Patent Literature]

[Patent document 1] Japanese Patent Publication No. 2011-190826

[Patent Document 2] International Publication No. 2015/136622

However, the previous oscillating gear device described in the patent document 2 needs to form two step surfaces on both sides of the width direction of the outer peripheral surface (cam surface) of the cam member in addition to the roller retainer, and cylindrical springs are respectively arranged on these two step surfaces to always press the rollers against the outer ring track surface. Therefore, in the previous oscillating gear device, each roller is always pressed by two cylindrical springs, resulting in increased friction loss, and the number of required parts also increases, so the manufacturing cost also increases. Therefore, there is still room for improvement.

The purpose of the present invention is to provide a ripple generator and a ripple gear device that can prevent deflection while reducing friction loss, thereby suppressing the manufacturing cost.

The oscillation generator of the oscillating gear device of the present invention comprises: a non-circular cam member capable of rotating around an axis; a plurality of rollers arranged on the outer circumference of the cam member; and a roller retainer for retaining the plurality of rollers. In the oscillation generator of the oscillating gear device, the roller retainer comprises a first roller retainer, which is shaped to form a plurality of rollers spaced apart in a circumferential direction. The first roller retainer is in a state of being mounted on the cam member together with the roller, and at least on the long axis side of the cam member, the roller is retained from the outer peripheral side of the ripple generator by a first mounting portion formed between the plurality of openings, and the roller is rotatably exposed to the outer peripheral side of the ripple generator through the opening.

In the oscillation generator of the oscillating gear device of the present invention, it can be set as follows: the roller retainer includes a second roller retainer, the second roller retainer is shaped into a flexible cylindrical shape with multiple openings formed at intervals in the circumferential direction, and the second roller retainer retains the roller from the cam member side through a second mounting portion formed between the multiple openings, and the roller is rotatably exposed to the cam member side through the opening.

In the oscillation generator of the oscillating gear device of the present invention, it can be set as follows: the first mounting portion has a retaining surface for retaining the roller in a rotatable manner, and the retaining surface is formed by an inclined surface or a curved surface.

In the oscillation generator of the oscillating gear device of the present invention, it can be set as follows: the first roller retainer is formed of resin or light metal.

In the oscillation generator of the oscillating gear device of the present invention, it can be set as follows: the cam member is non-circular in shape, and in the first roller retainer, the circumferential length hx1 between the roller in the opening (first opening) and the two contact points of the two first mounting parts satisfies the following formula (1), and the inner diameter D1 of the first roller retainer when the first roller retainer is a perfect circle satisfies the following formula (2).

(d: diameter of the roller, t1: thickness of the first roller retainer, x1: distance from the outer peripheral surface of the first roller retainer to the contact point between the roller and the first mounting portion

a+b+d<D1<2． (a+d)…(2)

(a: cam assembly major axis radius, b: cam assembly minor axis radius, d: roller diameter)

In the oscillation generator of the oscillating gear device of the present invention, it can be configured that: the second mounting portion has a retaining surface for retaining the roller in a rotatable manner, and the retaining surface is formed by an inclined surface or a curved surface.

In the oscillation generator of the oscillating gear device of the present invention, it can be set that: the second roller retainer is formed of resin or light metal.

In the oscillation generator of the oscillating gear device of the present invention, it can be configured that: the roller and the roller retainer form a roller bearing.

In the oscillation generator of the oscillating gear device of the present invention, it can be configured as follows: the roller bearing is formed by the roller, the roller retainer and the outer ring with flexibility.

In the oscillation generator of the oscillating gear device of the present invention, it can be configured as follows: a roller bearing is formed by at least the roller, the roller retainer and the flexible inner ring.

The oscillating gear device of the present invention comprises: an inner gear; an outer gear, which is flexible and arranged on the inner circumference of the inner gear; and a oscillation generator of the oscillating gear device described in any one of the above items, which is arranged on the inner circumference of the outer gear.

The present invention can provide a ripple generator and ripple gear device that can prevent deflection while reducing friction loss, thereby suppressing manufacturing costs.

1: Oscillating gear device

2: Inner gear

2a: Inner teeth of the inner gear

2b: The ring-shaped body of the inner gear

3: External gear

3a: External teeth of the external gear

3b: The annular body of the outer gear

4: Wave generator

5: Cam components

6: Roller

6e: Axial end of the roller

7: Roller retainer

7A: First roller retainer

7B: Second roller retainer

8: Drive shaft

11: Outer Ring

12: Inner Ring

71a: First annular portion (annular portion)

71b: Second annular portion (annular portion)

72a: The first installation department (installation department)

72b: Second installation department (installation department)

73a: First holding surface (holding surface)

73b: Second holding surface (holding surface)

74a: The outer peripheral edge of the first mounting portion (outer peripheral edge)

74b: The outer peripheral edge of the second mounting portion (outer peripheral edge)

75a: Inner peripheral edge of the first mounting portion (inner peripheral edge)

75b: Inner peripheral edge of the second mounting portion (inner peripheral edge)

a: Radius of the major axis of the cam assembly

b: The minor axis radius of the cam assembly

A1: First opening (opening)

A2: Second opening (opening)

B1~B3: Bearings

d: diameter of roller (diameter)

D1: Inner diameter of the first roller retainer when it is a perfect circle/Inner diameter of the first roller retainer when it is a perfect circle/Inner diameter of the first roller retainer when it is a perfect circle/Inner diameter of the first roller retainer

D2: The inner diameter of the second roller retainer when it is a perfect circle/the inner diameter of the second roller retainer when it is a perfect circle/the inner diameter of the second roller retainer when it is a perfect circle/the inner diameter of the second roller retainer/the inner diameter of the perfect circle

F3: Inner circumference of the outer gear

F5: Outer peripheral surface of cam component (cam surface)

F72a(out): Outer peripheral surface of the first roller retainer (gear side surface)/Outer peripheral side surface of the first roller retainer (outer peripheral side surface of the first mounting portion)

F72a (in): Inner circumference of the first roller retainer (cam component side surface)

F72b(out): Outer peripheral surface of the second roller retainer (gear side surface)

F72b (in): Inner circumferential surface of the second roller retainer (side surface of the cam member)/Inner circumferential surface of the second roller retainer (inner circumferential side surface of the second mounting portion)

h1: Circumferential length of the first opening

h2: Circumferential length of the second opening

h11: Circumferential length between the outer peripheral edges of the two first mounting parts

h12: Circumferential length between the inner circumferential edges of the two first mounting parts

h21: Circumferential length between the outer peripheral edges of the two second mounting parts

h22: Circumferential length between the inner peripheral edges of the two second mounting parts

hx1: length of the contact point in the first opening (the circumferential length between the roller in the first opening and the two contact points of the two first mounting parts)/contact point length

hx2: length of the contact point in the second opening (the circumferential length between the roller in the second opening and the two contact points of the two second mounting parts)/contact point length

O1: Axis (center axis of oscillating gear device 1)

O6: Axis (roller axis)/center axis of roller

P: The combined part

Px1: contact point (contact point)/contact line between the roller and the first retaining surface

Px2: contact point (contact point)/contact line between the roller and the second retaining surface

t1: Thickness of the first roller retainer (thickness of the first mounting portion)

t2: Thickness of the second roller retainer (thickness of the second mounting portion)

x1: Contact point distance in the first opening (the distance from the outer peripheral surface of the first roller retainer to the contact point between the roller and the first mounting portion)/Contact point distance

x2: Contact point distance in the second opening (the distance from the inner circumference of the second roller retainer to the contact point between the roller and the second mounting portion)/contact point distance

FIG1 is a diagram schematically showing a fluctuating gear device of one embodiment of the present invention from the axial direction.

FIG. 2 is a diagram schematically showing a ripple generator of one embodiment of the present invention used in the ripple gear device of FIG. 1 from the axial direction.

FIG. 3 is a diagram schematically showing the roller retainer unit used in the wave generator of FIG. 2 from the axial direction.

FIG. 4A is a diagram schematically showing the relationship between the roller and the roller retainer when the roller of the roller retainer unit of FIG. 3 is located at the short shaft portion of the cam member together with the cam member.

FIG. 4B is a diagram schematically showing the relationship between the roller and the roller retainer when the roller of the roller retainer unit of FIG. 3 is located on the long axis portion of the cam member together with the cam member.

FIG. 5 is a diagram schematically showing a roller retainer, which is a structural component of the wave generator of FIG. 2, together with the roller in a state where the plane is unfolded.

FIG. 6A is a diagram schematically illustrating a state in which the roller rolls appropriately on the outer peripheral surface of the cam member by means of a roller retainer that can constitute a wave generator of one embodiment of the present invention when the outer peripheral surface of the cam member is unfolded.

FIG. 6B is a diagram schematically illustrating a state in which the roller is tilted on the outer peripheral surface of the cam member when the outer peripheral surface of the cam member is unfolded.

FIG. 7A is a diagram for schematically illustrating the relationship between the dimensions of the roller retainer and the roller of the wave generator that can constitute an embodiment of the present invention in order to prevent the roller from falling out of the opening of the roller retainer.

FIG. 7B is another diagram for schematically illustrating the dimensional relationship between the roller retainer and the roller of the wave generator that can constitute an embodiment of the present invention in order to expose the roller from the opening of the roller retainer.

FIG8A is a diagram for schematically illustrating the relationship between the inner diameter of the first roller retainer when it is a perfect circle and the dimensions of the cam member and the roller.

FIG8B is another diagram used to schematically illustrate the relationship between the inner diameter of the first roller retainer when it is a perfect circle and the dimensions of the cam member and the roller.

FIG. 9A is a diagram for schematically illustrating the relationship between the inner diameter of the second roller retainer when it is a perfect circle and the dimensions of the cam member and the roller.

FIG. 9B is another diagram used to schematically illustrate the relationship between the inner diameter of the second roller retainer when it is a perfect circle and the dimensions of the cam member and the roller.

FIG. 10 is a diagram schematically showing an example of a roller bearing that can be used in the oscillating gear device and its oscillation generator of the present invention.

Below, the oscillating gear device and oscillating generator of the embodiment of the present invention are described with reference to the drawings.

In FIG. 1 , symbol 1 is a fluctuating gear device of an embodiment of the present invention. The fluctuating gear device 1 includes: an inner gear 2; an outer gear 3 having flexibility and arranged on the inner circumference of the inner gear 2; and a fluctuation generator 4 arranged on the inner circumference of the outer gear 3.

In the present disclosure, the inner gear 2 is an annular gear. The inner gear 2 includes a plurality of inner gears 2a and an annular body 2b. The plurality of inner gears 2a protrude inwardly from the inner circumferential diameter of the annular body 2b. In the present disclosure, the inner gear 2 is, for example, fixed to a housing (not shown) of the oscillating gear device 1. The inner gear 2 is fixed to the housing with the axis O1 as the center axis. In the present disclosure, the axis O1 is the center axis of the oscillating gear device 1. That is, in the present disclosure, the inner gear 2 is a fixed gear with the axis O1 as the center axis. Furthermore, in the present disclosure, the inner gear 2 is a rigid gear with high rigidity that is not easily deformed. The inner gear 2 is formed of, for example, iron-based materials such as cast iron, alloy steel, and carbon steel, light metal alloys or light metal elements such as magnesium alloys, aluminum alloys, and titanium alloys, and engineering plastics such as polyether ether ketone (PEEK), polyphenylene sulfide (PPS), and polyoxymethylene (POM).

In the present disclosure, the outer gear 3 is also an annular gear. The outer gear 3 includes a plurality of outer gears 3a and an annular body 3b. The plurality of outer gears 3a protrude radially outward from the outer circumference of the annular body 3b. In the present disclosure, the outer gear 3 is a rotating gear that can rotate around the axis O1. Furthermore, in the present disclosure, the outer gear 3 is a flexible gear that is easily deformable and has flexibility. The outer gear 3 can be mechanically deformed and restored, for example, by forming the annular body 3b into a thin wall. When the annular body 3b is formed into a thin wall, the material used to form the outer gear 3 can be, for example, metal or resin material. In addition, the outer gear 3 can be deformed and restored in terms of material by using, for example, a flexible material (for example, a thin-walled material including alloy steel, carbon steel, or light metal, or a resin material such as flexible engineering plastic).

The wave generator 4 includes: a non-circular cam member 5 capable of rotating around the axis O1; a plurality of rollers 6 arranged on the outer circumference of the cam member 5; and a roller retainer 7 for retaining the plurality of rollers 6.

In the present disclosure, the oscillation generator 4 further includes a drive shaft 8. The drive shaft 8 is connected to a power source such as a motor (not shown). In the present disclosure, the drive shaft 8 is connected to the cam member 5. The center axis (rotation axis) of the drive shaft 8 is coaxial with the axis O1. That is, in the present disclosure, the oscillation generator 4 is arranged on the same axis as the center axis of the oscillation gear device 1. Thereby, the cam member 5 can rotate around the axis O1.

In addition, when viewed along the axis O1 direction (when viewed from the extension direction of the axis O1), the cam member 5 has a non-circular shape. The cam member 5 is a member with high rigidity, similar to the inner gear 2. The outer peripheral surface F5 of the cam member 5 functions as a cam surface. In the present disclosure, the cam member 5 is a two-lobe shape. As shown in the figure, the two-lobe shape is an elliptical shape when viewed along the axis O1 direction.

FIG2 shows a wave generator 4 of an embodiment of the present invention alone.

In the present disclosure, the roller retainer 7 includes a first roller retainer 7A. The first roller retainer 7A is shaped into a flexible cylindrical shape with multiple openings A1 (hereinafter also referred to as "first openings A1") formed at intervals in the circumferential direction around the axis O1. In addition, as shown in FIG. 2, when the first roller retainer 7A is mounted on the cam member 5 together with the roller 6, at least on the long axis side of the cam member 5, the roller 6 is retained from the outer peripheral side of the ripple generator 4 (hereinafter also referred to as "the outer peripheral side of the ripple generator") by the mounting portion 72a (hereinafter also referred to as "the first mounting portion 72a") formed between the multiple first openings A1, and the roller 6 is rotatably exposed to the outer peripheral side of the ripple generator by the first opening A1.

Here, as shown in FIG2, the so-called "outer peripheral side of the oscillation generator" refers to, for example, a side away from the axis O1 when viewed along the axis O1. Alternatively, as shown in FIG1, the so-called "outer peripheral side of the oscillation generator" refers to the gear side of the outer gear 3 or the like when the oscillation generator 4 is arranged inside the oscillation gear device 1 when viewed along the axis O1 (hereinafter also referred to as the "gear side").

In addition, in the present disclosure, the roller retainer 7 includes a second roller retainer 7B. Referring to FIG. 2 , the second roller retainer 7B is shaped into a flexible cylindrical shape with multiple openings A2 (hereinafter also referred to as "second openings A2") spaced apart in the circumferential direction around the axis O1. In addition, the second roller retainer 7B retains the roller 6 from the cam member 5 side (hereinafter also referred to as "cam member side") by means of a mounting portion 72b (hereinafter also referred to as "second mounting portion 72b") formed between the multiple second openings A2, and the roller 6 is rotatably exposed to the cam member side by means of the second opening A2.

FIG3 schematically shows the bearing B1 used in the wave generator 4. In the present disclosure, the bearing B1 is a roller bearing that supports the cam member 5 and the outer gear 3 in a manner that allows them to rotate relative to each other.

In the present disclosure, the bearing B1 includes: a plurality of rollers 6, which are arranged at intervals in the circumferential direction around the axis O1; a first roller retainer 7A, which is flexible; and a second roller retainer 7B, which is also flexible. The plurality of rollers 6 are respectively retained in a rotatable manner by the first roller retainer 7A and the second roller retainer 7B. That is, in the present disclosure, the bearing B1 is a roller bearing in which the plurality of rollers 6 are integrated in a rotatable manner by the first roller retainer 7A and the second roller retainer 7B.

As shown in FIG3 , the bearing B1 is in a perfect circular shape in the initial state before being mounted on the cam member 5. In FIG3 , the axis O1 is shown as the center axis. Referring to FIG3 , in the present disclosure, in a state where a plurality of rollers 6 are assembled around the axis O1, the first roller retainer 7A and the second roller retainer 7B are arranged in a concentric circle shape with the axis O1 as the center. The second roller retainer 7B is arranged on the inner circumference side of the first roller retainer 7A at a distance in the radial direction relative to the first roller retainer 7A. That is, in the present disclosure, when viewed along the axis O1 direction, the first roller retainer 7A is equivalent to a perfect circular outer cylinder with the axis O1 as the center axis, and the second roller retainer 7B is equivalent to a perfect circular inner cylinder with the axis O1 as the center axis.

In the bearing B1, the first roller retainer 7A and the second roller retainer 7B are flexible. Therefore, as shown in FIG. 2, the bearing B1 can also be mounted on a non-circular cam member 5. In addition, in the present disclosure, the cam member side portion of the roller 6 is exposed to the cam member side through the second opening portion A2 of the second roller retainer 7B. Therefore, in the present disclosure, the bearing B1 can be mounted on the cam member 5 in a manner that the roller 6 is in direct contact with the outer peripheral surface (cam surface) F5 of the cam member 5.

The outer gear 3 is also flexible. Therefore, as shown in FIG. 1 , the outer gear 3 can be mounted on the wave generator 4. In the present disclosure, the gear side portion of the roller 6 is exposed to the gear side through the first opening portion A1 of the first roller retainer 7A. Therefore, in the present disclosure, the outer gear 3 can be mounted on the wave generator 4 in a manner that the roller 6 is in direct contact with the inner peripheral surface F3 of the outer gear 3.

In the wave generator 4 disclosed in the present invention, as shown in FIG3 , the roller bearing is a bearing B1 formed by the roller 6, the first roller retainer 7A, and the second roller retainer 7B.

As shown in FIG1 , the wave generator 4 can be assembled on the inner circumference F3 of the outer gear 3 to bend the outer gear 3 into a non-circular shape so that the outer gear 3a of the outer gear 3 and the inner gear 2a of the inner gear 2 are engaged. In the present disclosure, the outer gear 3 and the inner gear 2 are engaged at two positions of the long shaft portion of the cam member 5. In FIG1 , the symbol P represents the engagement portion P of the outer gear 3a of the outer gear 3 and the inner gear 2a of the inner gear 2. As shown in FIG1 , in the present disclosure, the engagement portion P is located on the two long shaft sides of the cam member 5.

In the wave generator 4, the cam member 5 rotates around the axis O1 as the drive shaft 8 rotates. As a result, the cam member 5 can rotate relative to the outer gear 3 via the roller 6 of the bearing B1. On the other hand, the inner gear 2 is fixed, and there is a tooth number difference (for example, the tooth number difference is 2) between the number of teeth ZF of the outer gear 3a of the outer gear 3 and the number of teeth ZR of the inner gear 2a of the inner gear 2. Therefore, when the cam member 5 is rotated, a relative rotation caused by the tooth number difference occurs between the inner gear 2 and the outer gear 3. Thereby, the engagement portion P of the outer gear 3 moves in the circumferential direction of the inner gear 2 in the direction opposite to the rotation direction of the cam member 5. In the present disclosure, every time the cam member 5 rotates 180 degrees around the axis O1, the engagement portion P moves in the direction opposite to the rotation direction of the wave generator 4 relative to the inner gear 2. That is, in the present disclosure, the input rotation from the drive shaft 8 is reversely output as the decelerated rotation from the outer gear 3.

On the other hand, FIG4A shows the relationship between the roller 6 and the roller retainer 7 when the roller 6 of the bearing B1 is located at the short shaft portion of the cam member 5, together with the cam member 5, with the cam member 5 and the roller retainer 7 being unfolded in a plane. FIG4A shows a cross section perpendicular to the center axis (axis O1) of the bearing B1 (hereinafter also referred to as an "axis vertical cross section").

The first roller retainer 7A prevents the roller 6 from falling off toward the gear side by means of the first bridge portion 72a formed between the first opening portions A1. On the other hand, the cam member 5 basically does not generate a pressing force from the cam member 5 to the roller 6 at a portion other than the long axis portion of the cam member 5 (for example, the short axis portion of the cam member 5). Therefore, as shown in FIG. 4A , the roller 6 covered by the first roller retainer 7A from the gear side does not contact the first roller retainer 7A at a portion other than the long axis portion of the cam member 5, for example, the short axis portion of the cam member 5, and becomes free. Therefore, the first roller retainer 7A reduces the friction loss caused by the contact between the first roller retainer 7A and the cam member 5, which may occur when the roller 6 passes through a portion other than the long axis portion of the cam member 5. In addition, as shown in FIG. 4A , the first roller retainer 7A is configured so that the gear side portion of the roller 6 is located in the first opening portion A1 by adjusting the inner diameter D1 when the first roller retainer 7A is a perfect circle. Therefore, the first roller retainer 7A maintains the interval between adjacent rollers 6 at an appropriate interval along the circumferential direction of the first roller retainer 7A.

On the other hand, FIG. 4B schematically shows the relationship between the roller 6 and the roller retainer 7 when the roller 6 of the bearing B1 is located on the long axis of the cam member 5, together with the cam member 5, in a state where the cam member 5 and the roller retainer 7 are unfolded in a plane. FIG. 4B also shows the vertical section of the shaft, similarly to FIG. 4A.

As shown in FIG. 4B , in the bearing B1, the roller 6 is pressed from the gear side by being clamped by the cam member 5 and the first roller retainer 7A (first mounting portion 72a) at the long axis portion of the cam member 5. Therefore, the roller 6 is arranged at the position of the first opening portion A1 of the first roller retainer 7A in a manner along the shape of the first opening portion A1. That is, in the present disclosure, the first roller retainer 7A, when mounted on the cam member 5 together with the roller 6, retains the roller 6 from the gear side at least at the long axis portion (long axis side) of the cam member 5 by the first mounting portion 72a formed between the plurality of first opening portions A1, and allows the roller 6 to be rotatably exposed to the gear side by the first opening portion A1. Thus, the roller 6 can roll relative to the outer peripheral surface F5 of the cam member 5 and the inner peripheral surface F3 of the outer gear 3 without causing deflection in the long axis portion of the cam member 5. Therefore, the first roller retainer 7A prevents the deflection of the roller 6 that may occur in the long axis portion of the cam member 5. As a result, the first roller retainer 7A also reduces the friction loss caused by the deflection of the roller 6.

As described above, the first roller retainer 7A has a structure that, when mounted on the non-circular cam member 5, the roller 6 is pressed from the gear side on the long shaft side of the cam member 5, and, on the other hand, the roller 6 is not pressed from the gear side on the short shaft side of the cam member 5. That is, when the first roller retainer 7A is mounted on the cam member 5 together with the roller 6, the roller 6 is held from the gear side by the first mounting portion 72a at least on the long shaft side of the cam member 5, and the roller 6 is rotatably exposed to the gear side by the first opening portion A1. Therefore, by the wave generator 4 of the present disclosure, at the portion other than the long axis portion of the cam member 5 (for example, the short axis portion of the cam member 5), although the roller 6 is covered by the first roller retainer 7A, it is not pressed by the first roller retainer 7A and the cam member 5. Therefore, by the wave generator 4 of the present disclosure, the friction loss that may be generated when the roller 6 passes through the portion other than the long axis portion of the cam member 5 is reduced. In addition, by the wave generator 4 of the present disclosure, at the long axis portion of the cam member 5, the roller 6 is restricted in a manner that does not cause deflection due to contact with the first mounting portion 72a, and is rotatably exposed from the first opening portion A1 to the gear side. Therefore, the ripple generator 4 of the present disclosure prevents the roller 6 from being deflected when passing through the long shaft of the cam member 5, thereby reducing the friction loss caused by the deflection. Therefore, the ripple generator 4 of the present disclosure can reduce friction loss while preventing deflection. In addition, the ripple gear device 1 of the present disclosure using the ripple generator 4 can reduce friction loss while preventing deflection.

In addition, when the first roller retainer 7A is shaped into a flexible cylindrical shape with multiple first openings A1 spaced apart in the circumferential direction as in the bearing B1 disclosed in the present invention, and is arranged in a manner covering the roller 6 from the gear side, the outer ring of the bearing is not a necessary structural part but an optional part.

On the other hand, the previous oscillating gear device described in Patent Document 2, in addition to configuring a roller retainer, also forms two step surfaces on both sides of the width direction of the outer peripheral surface (cam surface) of the cam member, and configures cylindrical springs on these two step surfaces, and covers the roller from the outer peripheral side of the oscillation generator by an outer ring. Therefore, the number of parts required in the previous oscillating gear device has also increased, so the manufacturing cost has also increased.

In contrast, the first roller retainer 7A disclosed in the present invention does not require additional parts such as a cylindrical spring. Therefore, the wave generator 4 disclosed in the present invention can reduce the number of parts required to suppress the occurrence of the deflection while suppressing the occurrence of the deflection, and as a result, the manufacturing cost can be reduced.

Therefore, the ripple generator 4 can be easily and cheaply manufactured to prevent deflection and reduce friction loss, and the ripple gear device 1 can be easily and cheaply manufactured.

In addition, in the present disclosure, as described in detail later, the first mounting portion 72a of the first roller retainer 7A has a retaining surface 73a (hereinafter also referred to as "first retaining surface 73a") that retains the roller 6 in a rotatable manner. The first retaining surface 73a can be formed by an inclined surface or a curved surface. In this case, the roller 6 can be arranged relative to the first opening portion A1 so that the roller 6 rolls more smoothly. Furthermore, in this case, the stress concentration when the first roller retainer 7A contacts the roller 6 can be alleviated.

Referring to FIG. 4A , in the present disclosure, the first opening portion A1 forms an outer peripheral side opening on the outer peripheral surface (gear side surface) F72a (out) of the first roller retainer 7A. The outer peripheral side opening extending along the width direction of the first roller retainer 7A is shaped by the outer peripheral side edge 74a of the first mounting portion 72a.

In addition, in the present disclosure, the first opening portion A1 forms an inner peripheral side opening on the inner peripheral surface (cam member side surface) F72a (in) of the first roller retainer 7A. The contour of the inner peripheral side opening extending along the width direction of the first roller retainer 7A is shaped by the inner peripheral side edge 75a of the first mounting portion 72a.

Here, in the present disclosure, the circumferential length h1 of the first opening portion A1 is the extended length of the first opening portion A1 extending along the circumferential direction of the first roller retainer 7A when the cylindrical first roller retainer 7A is unfolded in a plane.

As shown in FIG. 4A , in the present disclosure, when observing the vertical section from the axis (when observing along the axial direction), the first retaining surface 73a is inclined straightly from the outer peripheral side edge 74a to the inner peripheral side edge 75a in such a way that the circumferential length h11 between the outer peripheral side edges 74a of the two first mounting parts 72a in the circumferential direction length h1 of the first opening A1 is shorter than the circumferential length h12 between the inner peripheral side edges 75a of the two first mounting parts 72a. That is, the first retaining surface 73a is an inclined surface. Therefore, in the present disclosure, the circumferential length h1 of the first opening A1 becomes longer at a certain ratio from the outer peripheral surface F72a (out) to the inner peripheral surface F72a (in) of the first roller retainer 7A. Thus, as shown in FIG4B , when viewed in a vertical section from the axis, the roller 6 contacts the first holding surface 73a at the contact point Px1. That is, as shown in FIG4B , the roller 6 can rotate while being in line contact with the first roller retainer 7A along the width direction (the extension direction of the first mounting portion 72a) at the contact point Px1 with the first holding surface 73a when viewed in a vertical section from the axis. Therefore, by the first holding surface 73a of the present disclosure, the roller 6 can be arranged relative to the first opening portion A1, so that the roller 6 can rotate more smoothly relative to the first mounting portion 72a. Furthermore, in this case, since the first roller retainer 7A and the roller 6 are in line contact along the width direction of the first roller retainer 7A at the position of the contact point Px1, the stress concentration when the first roller retainer 7A and the roller 6 are in contact can be alleviated. Among them, the first retaining surface 73a can be set as a curved surface instead of the inclined surface described above. As a specific example of the curved surface, it can be set as a curved surface that bulges inward toward the outer peripheral side (gear side) of the first roller retainer 7A. The curved surface can be set as a curved surface with a radius of curvature of the radius of the roller 6, for example. In addition, the curved surface can also be set as a curved surface that bulges outward toward the inner peripheral side (cam component side) of the first roller retainer 7A.

FIG5 schematically shows the cylindrical first roller retainer 7A in a flat unfolded state, together with the roller 6, from the outer peripheral side (gear side) of the first roller retainer 7A.

Referring to FIG. 5 , in the present disclosure, roller 6 is a cylindrical component with a diameter d and an axis O6 (also referred to as "roller axis O6") as the center axis. In the present disclosure, roller 6 can be rotated around axis O6.

On the other hand, in the present disclosure, the first roller retainer 7A includes: two annular portions 71a (hereinafter also referred to as "first annular portions 71a"), arranged adjacent to the axial end 6e of the roller 6; and a plurality of first mounting portions 72a, connecting the two first annular portions 71a and arranged at intervals in the circumferential direction. That is, in the present disclosure, the first opening portion A1 is a quadrilateral opening portion demarcated by the two first annular portions 71a and the two first mounting portions 72a.

Referring to FIG. 5 , in the present disclosure, the first roller retainer 7A is covered by the roller 6 in such a manner that the outer peripheral edge 74a of the first mounting portion 72a is parallel to the axis O6 of the roller 6. In addition, the circumferential length h1 of the first opening A1 (in this example, the circumferential length h11 between the outer peripheral edge 74a of the two first mounting portions 72a) is shorter than the diameter d of the roller 6. In addition, in the present disclosure, as shown in FIG. 5 , a first retaining surface 73a is formed on the first mounting portion 72a, and the first retaining surface 73a is inclined with the outer peripheral edge 74a as the base point so as to be farther away from the outer peripheral edge 74a as it goes toward the inner peripheral side (the back side of the paper surface of FIG. 5 ) of the first roller retainer 7A. Thus, the gear side portion of the roller 6 (the side portion on the paper surface of FIG. 5 ) is exposed from the first opening portion A1 and is rotationally held at the contact point Px1 with the roller 6 on the first holding surface 73a (when viewed from the plan view of FIG. 5 , the contact point Px1 becomes the contact line Px1 extending along the width direction of the first roller retainer 7A). Furthermore, in the present disclosure, as shown in FIG. 5 , the two first annular portions 71a are arranged so as to form a gap between them and the axial end 6e of the roller 6. In this case, the friction loss is further reduced.

Next, FIG. 6A is a diagram that illustrates and schematically shows a state in which the roller 6 properly rolls on the outer peripheral surface F5 of the cam member 5 by the first roller retainer 7A when the outer peripheral surface F5 of the elliptical cam member 5 is unfolded. In FIG. 6A, the first opening A1 of the first roller retainer 7A is shown for reference in order to facilitate understanding of the relationship between the first opening A1 and the roller 6. In addition, FIG. 6B is a diagram that illustrates and schematically shows a state in which the roller 6 is deflected on the outer peripheral surface F5 of the cam member 5 when the outer peripheral surface F5 of the cam member 5 is unfolded.

Referring to FIG. 6A , it can be seen that the roller 6 can roll on the outer peripheral surface F5 of the cam member 5 without being deflected relative to the moving direction of the roller 6 by the first roller retainer 7A. In contrast, as shown in FIG. 6B , by using a waving gear device without a roller retainer, the roller 6 slides on the outer peripheral surface F5 of the cam member 5 while being deflected relative to the moving direction of the roller 6. This sliding generates friction loss caused by the deflection of the roller 6.

In addition, in the present disclosure, as described above, the cam member 5 is non-circular when viewed along the axis O1. In this case, the circumferential length hx1 (hereinafter also referred to as "contact point length hx1") between the roller 6 in the first opening A1 and the two contact points Px1 of the two first mounting portions 72a in the first roller retainer 7A can satisfy the following formula (1).

(d: diameter of roller 6, t1: thickness of first roller retainer 7A (thickness of first mounting portion 72a), x1: distance from outer peripheral surface F72a (out) of first roller retainer 7A to contact point Px1 between roller 6 and first mounting portion 72a (hereinafter also referred to as "contact point distance x1"))

Furthermore, when the cam member 5 is non-circular, the inner diameter D1 of the first roller retainer 7A when the first roller retainer 7A is a perfect circle (hereinafter also referred to as "the perfect circle inner diameter D1 of the first roller retainer 7A") satisfies the following formula (2).

[Formula 2] a+b+d<D1<2． (a+d)…(2)

(a: long axis radius of cam component 5, b: short axis radius of cam component 5, d: diameter of roller 6)

When the major axis radius a and minor axis radius b of the cam member 5, the diameter d of the roller 6, the thickness t1 of the first roller retainer 7A, the contact point distance x1 in the first opening A1, the contact point length hx1 and the inner diameter D1 of the perfect circle are set in a manner that satisfies the above equations (1) and (2) at the same time, as described in detail later, the roller 6, cam member 5 and first roller retainer 7A of appropriate sizes corresponding to the purpose, specifications, etc. can be easily derived. In this case, the ripple generator 4 that can prevent deflection and reduce friction loss can be manufactured more easily and cheaply, and the ripple gear device 1 can be manufactured more easily and cheaply.

Specifically, the above formula (1) is a relational formula focusing on the contact point length hx1 in the first opening portion A1 of the first roller cage 7A.

FIG. 7A is a diagram for schematically explaining the dimensional relationship between the first roller retainer 7A and the roller 6 so as to prevent the roller 6 from falling out of the first opening A1 of the first roller retainer 7A. FIG. 7A shows a cross section perpendicular to the axis, similar to FIG. 4A .

Here, the contact point length hx1 in the first opening A1 refers to the circumferential length between one roller 6 and the contact point Px1 of the two first mounting parts 72a that hold the one roller 6 in the circumferential length h1 of the first opening A1. The contact point length hx1 in the first opening A1 needs to be smaller than the diameter d of the roller 6 in order to prevent the roller 6 from falling off toward the gear side. Therefore, based on the geometric relationship shown in FIG. 7A, the contact point length hx1 in the first opening A1 and the diameter d of the roller 6 need to be set to satisfy the following relationship (1A).

[Formula 3] hx1<d…(1A)

If the contact point length hx1 in the first opening A1 and the diameter d of the roller 6 are set in a manner that satisfies the above-mentioned relational expression (1A), the roller 6 will not fall off from the first opening A1.

Next, FIG. 7B is a diagram for schematically explaining the dimensional relationship between the first roller retainer 7A and the roller 6 in order to expose the roller 6 from the first opening A1 of the first roller retainer 7A. FIG. 7B also shows a cross section perpendicular to the axis, similar to FIG. 4B .

In the present disclosure, the contact point length hx1 in the first opening portion A1 is required to prevent the roller 6 from falling out of the first opening portion A1 and to expose the roller 6 from the first opening portion A1. Therefore, based on the geometric relationship shown in FIG. 7B , the contact point distance x1 and the contact point length hx1 in the first opening portion A1, the diameter d of the roller 6, and the thickness t1 of the first roller retainer 7A (the thickness of the first mounting portion 72a) need to be set to satisfy the following relationship (1B). Here, the contact point distance x1 in the first opening A1 refers to the distance in the thickness direction of the first mounting portion 72a (first roller retainer 7A) from the outer peripheral surface F72a (out) of the first roller retainer 7A to the contact point Px1 when the cylindrical first roller retainer 7A is unfolded in a plane.

If the contact point distance x1 and the contact point length hx1 in the first opening portion A1, the diameter d of the roller 6, and the thickness t1 of the first roller retainer 7A are set in a manner that satisfies the above-mentioned relational expression (1B), the roller 6 can be exposed from the first opening portion A1. For example, it is necessary to lengthen the contact point length hx1 in the first opening portion A1 so that the gear side portion of the roller 6 protrudes further than the position of the outer peripheral side surface (outer peripheral side surface of the first mounting portion 72a) F72a (out) of the first roller retainer 7A. This condition is satisfied by setting the diameter d of the roller 6, the thickness t1 of the first roller retainer 7A, and the contact point distance x1 and the contact point length hx1 in the first opening A1 in a manner that satisfies the relational expression (1B).

It is also clear from the above-mentioned relational expressions (1A) and (1B) that the above-mentioned relational expression (1) focuses on the contact point length hx1 in the first opening portion A1. If the above-mentioned relational expression (1) is used, the diameter d of the roller 6 that can prevent the roller 6 from falling off from the first opening portion A1 and make it exposed from the first opening portion A1, the thickness t1 of the first roller retainer 7A (the thickness of the first mounting portion 72a), and the contact point distance x1 and the contact point length hx1 in the first opening portion A1 can be easily derived. In this case, it is easier and cheaper to manufacture the oscillation generator 4 that can prevent the roller 6 from falling off from the first opening A1 and expose it from the first opening A1, and further, it is easier and cheaper to manufacture the oscillation gear device 1 that can prevent the roller 6 from falling off from the first opening A1 and expose it from the first opening A1.

In addition, the above formula (2) is a relational formula focusing on the inner diameter D1 of the first roller retainer 7A when the first roller retainer 7A is in a perfect circular state.

FIG8A is a diagram for schematically illustrating the relationship between the inner diameter D1 (see FIG3 ) of the first roller retainer 7A when it is a perfect circle and the dimensions of the cam member 5 and the roller 6. In FIG8A , the bearing B2 of the second roller retainer 7B is omitted and mounted on the cam member 5. That is, in the present disclosure, the bearing B2 is formed by the roller 6 and the first roller retainer 7A.

Regarding the inner diameter D1 of the first roller retainer 7A when it is a perfect circle, it is necessary that, when the first roller retainer 7A is mounted on the cam member 5 together with the roller 6, a force that presses the roller 6 acts from the first roller retainer 7A toward the roller 6 side at least on the long axis side of the cam member 5. Therefore, regarding the inner diameter D1 of the first roller retainer 7A when it is a perfect circle, it is necessary to be at least smaller than the dimension when the roller 6 is arranged at each of the two long axis portions of the cam member 5. Referring to FIG. 8A , the dimension of the wave generator 4 in the long axis direction when the roller 6 is arranged at each of the two long axis portions of the cam member 5 is a value obtained by doubling the sum of the long axis radius a of the cam member 5 and the diameter d of the roller 6 ((a+d)×2). Therefore, it is necessary to set the inner diameter D1 of the first roller retainer 7A, the major axis radius a of the cam member 5, and the diameter d of the roller 6 to satisfy the following relationship (2A).

[Formula 5] D1<2. (a+d)…(2A)

As shown in FIG8A , if the inner diameter D1 of the first roller retainer 7A, the major axis radius a of the cam member 5, and the diameter d of the roller 6 are set in a manner that satisfies the above-mentioned relational expression (2A), then when the first roller retainer 7A and the roller 6 are mounted on the cam member 5 together, a force that acts as if the first roller retainer 7A presses the roller 6 can be applied at least on the major axis side of the cam member 5.

FIG8B is another diagram used to schematically illustrate the relationship between the inner diameter D1 of the first roller retainer 7A when it is a perfect circle and the dimensions of the cam member 5 and the roller 6. In FIG8B , the bearing B2 is also mounted on the cam member 5.

The inner diameter D1 of the first roller retainer 7A when in a perfect circle needs to be increased so that the position of the inner circumferential surface F72a (in) of the first roller retainer 7A deformed on the long axis side of the cam member 5 is located closer to the gear side (outer circumferential side of the wave generator 4) than the position of the roller axis O6 on the cam member 5 on the long axis side. This is because when the first roller retainer 7A is deformed on the long axis side of the cam member 5, when the position of the inner circumferential surface F72a (in) of the first roller retainer 7A is located closer to the cam member side than the position of the center axis O6 of the roller 6 on the cam member 5, it is difficult to press the roller 6 into the first opening portion A1 by the first mounting portion 72a. Therefore, referring to FIG. 8B , it is necessary to set the major axis radius a and minor axis radius b of the cam member 5 and the diameter d of the roller 6 to satisfy the following relationship (2B) according to the Gauss-Kummer formula.

[Formula 6] a+b+d<D1…(2B)

If the major axis radius a and minor axis radius b of the cam member 5, the perfect circle inner diameter D1 of the first roller retainer 7A, and the diameter d of the roller 6 are set in a manner that satisfies the above-mentioned relational expression (2B), then when the first roller retainer 7A is deformed on the major axis side of the cam member 5, the position of the first roller retainer 7A is closer to the gear side than the center axis O6 of the roller 6 on the cam member 5. Thus, when the first roller retainer 7A is deformed on the major axis side of the cam member 5, the first roller retainer 7A can press the roller 6 into the first opening A1 through the first mounting portion 72a.

It is also clear from the above-mentioned relational expressions (2A) and (2B) that the above-mentioned relational expression (2) focuses on the inner diameter D1 of the first roller retainer 7A when it is a perfect circle. If the above-mentioned relational expression (2) is used, it is easy to derive the radius a of the major axis and the radius b of the minor axis of the cam member 5, the diameter d of the roller 6, and the inner diameter D1 of the first roller retainer 7A when it is a perfect circle, when the first roller retainer 7A is mounted on the cam member 5 together with the roller 6, so that the gear side portion of the roller 6 is exposed from the first opening portion A1 of the first roller retainer 7A at least on the major axis side of the cam member 5, and the roller 6 is pressed toward the cam member side by the first mounting portion 72a of the first roller retainer 7A. In this case, it is easier and cheaper to manufacture the ripple generator 4 in which the gear side portion of the roller 6 is exposed from the first opening portion A1 of the first roller retainer 7A at least on the long axis side of the cam member 5, and the roller 6 is pressed toward the cam member side by the first mounting portion 72a of the first roller retainer 7A. Furthermore, it is easier and cheaper to manufacture the ripple gear device 1 in which the gear side portion of the roller 6 is exposed from the first opening portion A1 of the first roller retainer 7A, and the roller 6 is pressed toward the cam member side by the first mounting portion 72a of the first roller retainer 7A.

Therefore, by using the above formula (1) and formula (2), it is easy to derive the roller 6, cam member 5, and first roller retainer 7A of appropriate size corresponding to the purpose, specification, etc. In this case, it is easier and cheaper to manufacture the ripple generator 4 that can prevent deflection and reduce friction loss, and further, it is easier and cheaper to manufacture the ripple gear device 1.

In addition, referring to FIG. 4A , in the present disclosure, the roller retainer 7 includes a second roller retainer 7B. As shown in FIG. 4A , the second roller retainer 7B prevents the roller 6 from falling off toward the cam member side by means of the second mounting portion 72b. On the other hand, as described above, the cam member 5 basically does not generate a pressing force from the cam member 5 to the roller 6 at a portion other than the long axis portion of the cam member 5 (for example, the short axis portion of the cam member 5). Therefore, as shown in FIG. 4A , even when the second roller retainer 7B is included, the roller 6 does not contact the second roller retainer 7B, for example, at the short axis portion of the cam member 5, and becomes a free state. Therefore, even when the second roller retainer 7B is included, the friction loss caused by the contact between the roller retainer 7 and the cam member 5, which may occur when the roller 6 passes through a portion other than the long axis portion of the cam member 5, is reduced. In addition, as shown in FIG. 4A , the second roller retainer 7B is configured such that the cam member side portion of the roller 6 is located in the second opening portion A2 via the second opening portion A2. Therefore, the interval between the adjacent rollers 6 is maintained at an appropriate interval along the circumferential direction of the second roller retainer 7B by the second roller retainer 7B.

On the other hand, as shown in Fig. 4B, the second roller retainer 7B also generates no pressing force on the roller 6 at the long axis portion of the cam member 5. Therefore, even when the second roller retainer 7B is included, the roller 6 is pressed only from the gear side by being sandwiched between the cam member 5 and the first roller retainer 7A (first mounting portion 72a) at the long axis portion of the cam member 5. Therefore, in the present disclosure, when the second roller retainer 7B is installed on the cam member 5 together with the roller 6 and the first roller retainer 7A, at least on the short axis side (short axis portion) of the cam member 5, the roller 6 is allowed to move freely between the first roller retainer 7A and the second roller retainer 7B, and the roller 6 is retained in a manner that does not fall off from the cam member side by the second mounting portion 72b formed between the plurality of second opening portions A2, and at least on the long axis side (long axis portion) of the cam member 5, contact with the second mounting portion 72b is avoided as much as possible and the roller 6 is rotatably exposed to the cam member side by the second opening portion A2. Furthermore, as shown in FIG. 4A and FIG. 4B , at least on the long axis side (long axis portion) of the cam member 5, in the second opening portion A2 of the second roller retainer 7B, the roller 6 is arranged in the second opening portion A2 in a manner along the shape of the second opening portion A2 of the second roller retainer 7B. Thus, even when the second roller retainer 7B is included, the roller 6 can roll relative to the outer peripheral surface F5 of the cam member 5 and the inner peripheral surface F3 of the outer gear 3 without causing deflection in the long axis portion of the cam member 5. Therefore, the second roller retainer 7B can prevent the deflection of the roller 6 that may occur in the long axis portion of the cam member 5, similarly to the first roller retainer 7A. As a result, the friction loss caused by the deflection of the roller 6 is reduced by the second roller retainer 7B, similarly to the first roller retainer 7A. Therefore, when the second roller retainer 7B is added to the ripple generator 4 of the present disclosure, the deflection can be prevented while reducing the friction loss. Furthermore, the ripple gear device 1 of the present disclosure using the ripple generator 4 can also prevent the deflection while reducing the friction loss.

In addition, when the second roller retainer 7B is shaped into a flexible cylindrical shape with multiple second openings A2 spaced apart in the circumferential direction, and is arranged so as to cover the roller 6 from the inner circumference of the ripple generator 4, the inner ring of the bearing is not a necessary structural part but an optional part.

On the other hand, the previous oscillating gear device described in Patent Document 2, in addition to configuring a roller retainer, also forms two step surfaces on both sides of the width direction of the outer peripheral surface (cam surface) of the cam member, and configures cylindrical springs on these two step surfaces, and covers the roller from the inner peripheral side of the oscillation generator by an inner ring. Therefore, the number of parts required in the previous oscillating gear device has also increased, so the manufacturing cost has also increased.

In contrast, the second roller retainer 7B disclosed in the present invention does not require additional parts such as a cylindrical spring. Therefore, the wave generator 4 disclosed in the present invention can reduce the number of parts required to suppress the occurrence of the deflection while suppressing the occurrence of the deflection, and as a result, the manufacturing cost can be reduced.

Therefore, when the second roller retainer 7B is added as in the present disclosure, the ripple generator 4 that can reduce friction loss and prevent deflection can be easily and cheaply manufactured, and the ripple gear device 1 that can reduce friction loss and prevent deflection can be easily and cheaply manufactured.

In addition, when the second roller retainer 7B is added, the second roller retainer 7B retains the roller 6 from the cam member 5 side. In this case, the roller 6 (rolling element) and the roller retainer (retainer) can be handled as a bearing B1 as a whole as in the present disclosure. In this case, as in the present disclosure, the bearing B1 can be used as a single bearing in a single body, such as for circulation, transportation, or as a part during assembly. Therefore, the bearing B1 becomes a bearing with good assembly performance when assembled to the cam member 5 on the other side. Therefore, if the bearing B1 is used, the friction loss can be reduced while preventing deflection, and the assembly performance to the cam member can also be improved. In this way, if the bearing B1 is used, the ripple generator 4 that can prevent deflection and reduce friction loss can be easily and cheaply manufactured, and the ripple gear device 1 can be easily and cheaply manufactured.

In addition, in the present disclosure, the second mounting portion 72b of the second roller retainer 7B also has a retaining surface 73b (hereinafter also referred to as "second retaining surface 73b") that retains the roller 6 in a rotatable manner. The second retaining surface 73b can be formed by an inclined surface or a curved surface, similar to the first retaining surface 73a. In this case, the roller 6 can be arranged relative to the second opening portion A2, similar to the first retaining surface 73a, so that the roller 6 rolls more smoothly. Furthermore, in this case, the stress concentration when the second roller retainer 7B contacts the roller 6 can be alleviated.

Referring to FIG. 4B , in the present disclosure, the second opening portion A2 forms an inner peripheral side opening on the inner peripheral surface (cam member side surface) F72b (in) of the second roller retainer 7B. The inner peripheral side opening extends along the width direction of the second roller retainer 7B. The contour of the inner peripheral side opening is shaped by the inner peripheral side edge 75b of the second mounting portion 72b.

In addition, in the present disclosure, the second opening portion A2 forms an outer peripheral opening on the outer peripheral surface (gear side surface) F72b (out) of the second roller retainer 7B. The contour of the outer peripheral opening extending along the width direction of the second roller retainer 7B is shaped by the outer peripheral edge 74b of the second mounting portion 72b.

Here, in this disclosure, the so-called circumferential length h2 of the second opening portion A2 refers to the extended length of the second opening portion A2 extending along the circumferential direction of the second roller retainer 7B when the cylindrical second roller retainer 7B is unfolded in a plane.

As shown in FIG. 4B , in the present disclosure, when observing the vertical section from the axis (when observing along the axial direction), the second retaining surface 73b is inclined straightly from the inner circumferential side edge 75b to the outer circumferential side edge 74b in such a way that the circumferential length h22 between the inner circumferential side edges 75b of the two second mounting parts 72b in the circumferential direction length h2 of the second opening part A2 is shorter than the circumferential length h21 between the outer circumferential side edges 74b of the two second mounting parts 72b. That is, the second retaining surface 73b is also an inclined surface. Therefore, in the present disclosure, the circumferential length h2 of the second opening part A2 becomes longer at a certain ratio from the inner circumferential surface F72b (in) of the second roller retainer 7B to the outer circumferential surface F72b (out). Thus, as shown in FIG. 7A described later, when viewed from a vertical section, the roller 6 can contact the second holding surface 73b at the contact point Px2. That is, as shown in FIG. 7A, the roller 6 can rotate while being in line contact with the second roller retainer 7B along the width direction (extending direction of the second mounting portion 72b) at the contact point Px2 with the second holding surface 73b when viewed from a vertical section. Therefore, by the second holding surface 73b of the present disclosure, the roller 6 can be arranged relative to the second opening portion A2 in the same manner as the first holding surface 73a of the first roller retainer 7A, so that the roller 6 can rotate more smoothly relative to the second mounting portion 72b. Furthermore, in this case, since the second roller retainer 7B and the roller 6 are in line contact along the width direction of the second roller retainer 7B at the position of the contact point Px2, similarly to the first retaining surface 73a, the stress concentration when the second roller retainer 7B and the roller 6 are in contact can be alleviated. Among them, the second retaining surface 73b, like the first retaining surface 73a, can also be set as a curved surface instead of the inclined surface described above. As a specific example of the curved surface, it can be set as a curved surface that bulges inward toward the inner peripheral side (cam member side) of the second roller retainer 7B. The curved surface can be set as a curved surface with a radius of curvature of the radius of the roller 6, for example. In addition, the curved surface may also be a curved surface that protrudes outward toward the outer peripheral side (gear side) of the second roller retainer 7B.

In addition, when FIG. 5 is assumed to be observed from the inner peripheral surface side (cam member side) of the second roller retainer 7B, referring to the aforementioned FIG. 5, in the present disclosure, the second roller retainer 7B, like the first roller retainer 7A, also includes: two annular portions 71b (hereinafter also referred to as "second annular portions 71b"), arranged adjacent to the axial end 6e of the plurality of rollers 6; and a plurality of second mounting portions 72b, connecting the two second annular portions 71b and arranged at intervals in the circumferential direction. That is, in the present disclosure, the second opening portion A2, like the first roller retainer 7A, is also a quadrilateral opening portion demarcated by the two second annular portions 71b and the two second mounting portions 72b.

Referring to FIG. 5 , in the present disclosure, the second roller retainer 7B is also covered by the roller 6 in such a manner that the inner peripheral edge 75b of the second mounting portion 72b is parallel to the axis O6 of the roller 6. In addition, the circumferential length h2 of the second opening A2 (in this example, the circumferential length h22 between the inner peripheral edge 75b of the two second mounting portions 72b) is shorter than the diameter d of the roller 6. In addition, in the present disclosure, as shown in FIG. 5 , a second retaining surface 73b is formed on the second mounting portion 72b, and the second retaining surface 73b is inclined with the inner peripheral edge 75b as the base point so as to be farther away from the inner peripheral edge 75b as it goes toward the outer peripheral side (the back side of the paper surface of FIG. 5 ) of the second roller retainer 7B. Thus, the cam member side (surface side of the paper in FIG. 5 ) of the roller 6 is partially exposed from the second opening A2 and can be rotationally held at the contact point Px2 with the roller 6 on the second holding surface 73b (when viewed from the plan view in FIG. 5 , the contact point Px2 becomes the contact line Px2 extending along the width direction of the second roller retainer 7B). Furthermore, in the present disclosure, as shown in FIG. 5 , the two second annular portions 71b are also configured to form a gap between them and the axial end 6e of the roller 6. In this case, the friction loss is further reduced.

In addition, as shown in FIG. 6A , the roller 6 can also roll on the outer peripheral surface F5 of the cam member 5 without being tilted relative to the moving direction of the roller 6 by means of the second roller retainer 7B.

In addition, it can be set that in the second roller retainer 7B, the circumferential length hx2 between the roller 6 in the second opening portion A2 and the two contact points Px2 of the two second mounting portions 72b (hereinafter also referred to as "contact point length hx2") satisfies the following formula (3).

[Formula 7]

(d: diameter of roller 6, t2: thickness of second roller retainer 7B (thickness of second mounting portion 72b), x2: distance from inner circumference F72b (in) of second roller retainer 7B to the contact point between roller 6 and second mounting portion 72b (hereinafter also referred to as "contact point distance x2"))

Furthermore, when the cam member 5 is non-circular, the inner diameter D2 of the second roller retainer 7B when the second roller retainer 7B is a perfect circle (hereinafter also referred to as "the perfect circle inner diameter D2 of the second roller retainer 7B") satisfies the following formula (4).

[Formula 8]a+b<D2<a+b+d…(4)

(a: cam assembly major axis radius, b: cam assembly minor axis radius, d: roller diameter)

When the major axis radius a and minor axis radius b of the cam member 5, the diameter d of the roller 6, the thickness t2 of the second roller retainer 7B, the contact point distance x2 in the second opening A2, the contact point length hx2, and the inner diameter D2 of the perfect circle are set in a manner that satisfies the above-mentioned equations (3) and (4) at the same time, as described in detail later, the roller 6, cam member 5, and second roller retainer 7B of appropriate sizes corresponding to the purpose, specifications, etc. can be easily derived. In this case, the ripple generator 4 that reduces friction loss and prevents deflection can be manufactured more easily and cheaply, and the ripple gear device 1 that reduces friction loss and prevents deflection can be manufactured more easily and cheaply.

Specifically, the above formula (3) is a relational formula focusing on the contact point length hx2 in the second opening portion A2 of the second roller retainer 7B, similarly to the first roller retainer 7A.

Here, the so-called contact point length hx2 in the second opening portion A2 refers to the circumferential length between one roller 6 and the contact point Px2 of the two second mounting portions 72b holding the one roller 6 in the circumferential length h2 of the second opening portion A2. Referring to FIG7A, the contact point length hx2 in the second opening portion A2 needs to be set smaller than the diameter d of the roller 6 in order to prevent the roller 6 from falling off toward the cam member, similarly to the first roller retainer 7A. Therefore, similarly to the first roller retainer 7A, based on the geometric relationship shown in FIG7A, the contact point length hx2 in the second opening portion A2 and the diameter d of the roller 6 need to be set to satisfy the following relationship (3A).

[Formula 9] hx2<d…(3A)

If the contact point length hx2 in the second opening A2 and the diameter d of the roller 6 are set in a manner that satisfies the relationship (3A), the roller 6 will not fall off from the second opening A2.

Next, referring to FIG. 7B , in the present disclosure, the contact point length hx2 in the second opening A2 is similar to the contact point length hx1 in the first opening A1, and in addition to preventing the roller 6 from falling out of the second opening A2, the roller 6 needs to be exposed from the second opening A2. Therefore, similar to the first roller retainer 7A, based on the geometric relationship shown in FIG. 7B , the contact point distance x2 and the contact point length hx2 in the second opening A2, the diameter d of the roller 6, and the thickness t2 of the second roller retainer 7B (the second mounting portion 72b) need to be set to satisfy the following relationship (3B). Here, the contact point distance x2 in the second opening A2 refers to the distance in the thickness direction of the second mounting portion 72b (second roller retainer 7B) from the inner circumferential surface F72b (in) of the second roller retainer 7B to the contact point Px2 when the cylindrical second roller retainer 7B is unfolded.

If the contact point distance x2 and the contact point length hx2 in the second opening portion A2, the diameter d of the roller 6, and the thickness t2 of the second roller retainer 7B are set in a manner that satisfies the above-mentioned relational expression (3B), the roller 6 can be exposed from the second opening portion A2 in the same manner as the first roller retainer 7A. For example, it is necessary to lengthen the contact point length hx2 in the second opening portion A2 so that the cam member side portion of the roller 6 protrudes further than the position of the inner peripheral surface (inner peripheral side surface of the second mounting portion 72b) F72b (in) of the second roller retainer 7B. This condition is satisfied by setting the diameter d of the roller 6, the thickness t2 of the second roller retainer 7B, and the contact point distance x2 and the contact point length hx2 in the second opening A2 in a manner that satisfies the relational expression (3B).

It is also clear from the above-mentioned relational expressions (3A) and (3B) that the above-mentioned expression (3) focuses on the contact point length hx2 in the second opening portion A2. If the above-mentioned expression (3) is used, the diameter d of the roller 6 that can prevent the roller 6 from falling off from the second opening portion A2 and make it exposed from the second opening portion A2, the thickness t2 of the second roller retainer 7B (the thickness of the second mounting portion 72b), and the contact point distance x2 and the contact point length hx2 in the second opening portion A2 can be easily derived. In this case, it is easier and cheaper to manufacture the oscillation generator 4 that can prevent the roller 6 from falling off from the second opening A2 and expose the roller 6 from the second opening A2, and further, it is easier and cheaper to manufacture the oscillation gear device 1 that can prevent the roller 6 from falling off from the second opening A2 and expose the roller 6 from the second opening A2.

In addition, the above formula (4) is a relational formula focusing on the inner diameter D2 of the second roller retainer 7B when the second roller retainer 7B is in a perfect circular state.

FIG8A is a diagram for schematically illustrating the relationship between the inner diameter D2 of the second roller retainer 7B when it is a perfect circle and the dimensions of the cam member 5 and the roller 6.

The inner diameter D2 of the second roller retainer 7B when in a perfect circle needs to be reduced so that the position of the inner circumferential surface F72b (in) of the second roller retainer 7B deformed on the long axis side of the cam member 5 is located closer to the cam member side than the position of the roller axis O6 on the cam member 5 on the long axis side. This is because when the second roller retainer 7B is deformed on the long axis side of the cam member 5, if the position of the inner circumferential surface F72b (in) of the second roller retainer 7B is located closer to the gear side than the position of the center axis O6 of the roller 6 on the cam member 5, there is a possibility that interference occurs with the first roller retainer 7A located closer to the gear side than the roller 6. Therefore, referring to FIG. 9A , it is necessary to set the major axis radius a and minor axis radius b of the cam member 5 and the diameter d of the roller 6 to satisfy the following relationship (4A) according to the Gauss-Kummer formula.

[Formula 11]D2<a+b+d…(4A)

If the inner diameter D2 of the second roller retainer 7B, the major axis radius a of the cam member 5, and the diameter d of the roller 6 are set in a manner that satisfies the above-mentioned relationship (4A), the second roller retainer 7B will not accidentally interfere with the roller 6, and will not interfere with the first roller retainer 7A.

FIG. 9B is another diagram used to schematically illustrate the relationship between the inner diameter D2 of the second roller retainer 7B when it is a perfect circle and the dimensions of the cam member 5 and the roller 6.

It is necessary to increase the inner diameter D2 of the second roller retainer 7B when in a perfect circle so that the circumference of the inner peripheral surface F72b (in) of the second roller retainer 7B is longer than the circumference of the outer peripheral surface F5 of the cam member 5. Here, the so-called "circumference" refers to the "length in the circumferential direction around the axis O1". This is because when the inner diameter D2 of the second roller retainer 7B when in a perfect circle is reduced in such a way that the circumference of the inner peripheral surface F72b (in) of the second roller retainer 7B is shorter than the circumference of the outer peripheral surface F5 of the cam member 5, when the circumference is smaller than that of the cam member 5, the second roller retainer 7B and the cam member 5 may come into contact. Therefore, referring to FIG. 9B , it is necessary to set the major axis radius a and the minor axis radius b of the cam member 5 to satisfy the following relationship according to the Gauss-Kummer formula (4B).

[Formula 12] a+b<D2…(4B)

If the major axis radius a and the minor axis radius b of the cam member 5 are set in a manner that satisfies the relationship (4B), the second roller retainer 7B can be prevented from contacting the cam member 5. That is, if the major axis radius a and the minor axis radius b of the cam member 5 are set in a manner that satisfies the relationship (4B), the second roller retainer 7B and the cam member 5 will not interfere with each other.

Based on the above-mentioned relational equations (4A) and (4B), it is also clear that the above-mentioned equation (4) focuses on the inner diameter D2 of the second roller retainer 7B when it is a perfect circle. If the above-mentioned equation (4) is used, it is easy to derive the major axis radius a and the minor axis radius b of the cam member 5, the diameter d of the roller 6, and the inner diameter D2 of the second roller retainer 7B when it is a perfect circle, so as to expose the gear side portion of the roller 6 from the second opening portion A2 of the second roller retainer 7B without accidentally interfering with the roller 6, and further without interfering with the first roller retainer 7A and the cam member 5.

Therefore, by using the above formula (3) and formula (4), it is easy to derive the roller 6, cam member 5, and second roller retainer 7B of appropriate sizes corresponding to the application, specifications, etc.

In the present disclosure, the first roller retainer 7A may be formed of a resin or a light metal. In this case, the first roller retainer 7A may be easily manufactured by using existing materials. That is, in this case, the ripple generator 4 may be easily manufactured by using existing materials, and the ripple gear device 1 may be easily manufactured as a result. Furthermore, in the present disclosure, the second roller retainer 7B may also be formed of a resin or a light metal. In this case, the ripple generator 4 may also be easily manufactured by using existing materials, and the ripple gear device 1 may be easily manufactured as a result.

The roller retainer 7 can be formed of a resin material such as aluminum alloy, titanium alloy, or a flexible light metal alloy or light metal element such as these, PEEK (polyetheretherketone), PPS (polyphenylene sulfide), or POM (polyoxymethylene) or other engineering plastics.

In addition, in the present disclosure, the ripple generator 4 is preferably a roller bearing including a bearing B2 as shown in FIG. 8A and FIG. 8B. In the present disclosure, the bearing B2 is formed by a roller 6 and a first roller retainer 7A. In this case, the two components of the inner ring and the outer ring are omitted in the bearing B2. Therefore, in this case, the ripple generator 4 can be miniaturized, and as a result, the ripple gear device 1 can be miniaturized.

Among them, in the oscillating gear device and the oscillating generator of the present invention, the roller bearing can be formed by the roller 6, the first roller retainer 7A, and the flexible outer ring 11. In this case, when such a bearing is installed on the cam member 5, the gear side portion of the roller 6 rolls on the track surface of the outer ring 11. Therefore, in this case, the roller 6 can roll smoothly on the outer peripheral side of the oscillating generator 4.

In addition, in the oscillating gear device and oscillating generator of the present invention, the roller bearing may be formed by at least the roller 6, the first roller retainer 7A, and the flexible inner ring 12. In this case, when such a roller bearing is mounted on the cam member 5, the cam member side portion of the roller 6 rolls on the track surface of the inner ring 12. Therefore, in this case, the roller 6 can roll smoothly on the cam member side.

Here, FIG. 10 schematically shows an example of a roller bearing that can be used in the oscillating gear device and its oscillation generator of the present invention.

As described above, in the ripple generator and ripple gear device disclosed in the present invention, a bearing having a structure in which only the first roller retainer 7A covers the roller 6, such as the bearing B2 in FIG. 8A. On the other hand, the bearing B3 in FIG. 10 includes the roller 6, the first roller retainer 7A, the flexible outer ring 11, and the flexible inner ring 12. The bearing B3 includes only the first roller retainer 7A as the roller retainer 7 between the outer ring 11 and the inner ring 12. Among them, the second roller retainer 7B can be added to the bearing B3. In addition, as a modification of the bearing B3, a modification in which either the outer ring 11 or the inner ring 12 is omitted is also included.

As described above, the oscillation generator and oscillation gear device disclosed in the present invention can provide an oscillation generator and oscillation gear device that can prevent deflection while reducing friction loss, thereby suppressing the manufacturing cost.

The contents described above only show exemplary embodiments of the present invention, and various changes can be made in accordance with the scope of the patent application. In the present embodiment, the oscillating gear device 1 and the oscillating generator 4 are described as being in a two-leaf shape, but the oscillating gear device 1 and the oscillating generator 4 are not limited to the two-leaf shape. For example, the cam member 5 can be set to a multi-leaf shape. As specific examples of the cam member 5, for example, a triangular three-leaf shape and a quadrilateral four-leaf shape can be cited. In addition, in the above description, the power transmission path of the oscillating gear device 1 is set to have the oscillating generator 4 as an input and the external gear 3 as an output, but it is not limited to this. For example, the power transmission path of the oscillating gear device 1 can also be set to have the outer gear 3 as input and the oscillating generator 4 as output.

1: Oscillating gear device

2: Inner gear

2a: Inner teeth of the inner gear

2b: The ring-shaped body of the inner gear

3: External gear

3a: External teeth of the external gear

3b: The annular body of the outer gear

4: Wave generator

5: Cam components

6: Roller

7: Roller retainer

7A: First roller retainer

7B: Second roller retainer

8: Drive shaft

B1: Bearing

F3: Inner circumference of the outer gear

F5: Outer peripheral surface of cam component (cam surface)

O1: Axis (center axis of oscillating gear device 1)

P: The combined part

Claims (11)

A ripple generator of a ripple gear device, comprising: a non-circular cam member capable of rotating about an axis; a plurality of rollers arranged on the outer circumference of the cam member; and a roller retainer for retaining the plurality of rollers, wherein the ripple generator of the ripple gear device comprises a first roller retainer, wherein the first roller retainer is shaped to form a plurality of rollers spaced apart in a circumferential direction. The first roller retainer is in a state of being mounted on the cam member together with the roller, and at least on the long axis side of the cam member, the roller is retained from the outer peripheral side of the ripple generator by a first mounting portion formed between the plurality of openings, and the roller is rotatably exposed to the outer peripheral side of the ripple generator through the opening. The oscillation generator of the oscillating gear device as described in claim 1, wherein the roller retainer includes a second roller retainer, the second roller retainer is shaped as a flexible cylinder having multiple openings spaced apart in the circumferential direction, and the second roller retainer retains the roller from the cam member side by a second mounting portion formed between the multiple openings, and the roller is rotatably exposed to the cam member side by the opening. A fluctuation generator of a fluctuation gear device as described in claim 1 or 2, wherein the first mounting portion has a retaining surface for retaining the roller in a rotatable manner, and the retaining surface is formed by an inclined surface or a curved surface. A fluctuation generator of a fluctuation gear device as described in claim 1 or 2, wherein the first roller retainer is formed of resin or light metal. A fluctuation generator of a fluctuation gear device as described in claim 1 or 2, wherein the cam member is non-circular in shape, and in the first roller retainer, the circumferential length hx1 between the roller in the opening portion and the two contact points of the two first mounting portions satisfies the following formula (1), and the inner diameter D1 of the first roller retainer when the first roller retainer is a perfect circle satisfies the following formula (2),

(d: diameter of roller, t1: thickness of first roller retainer, x1: distance from the outer peripheral surface of first roller retainer to the contact point between the roller and the first mounting portion) a+b+d<D1<2. (a+d)…(2) (a: major axis radius of cam member, b: minor axis radius of cam member, d: diameter of roller). The oscillation generator of the oscillating gear device as described in claim 2, wherein the second mounting portion has a retaining surface for retaining the roller in a rotatable manner, and the retaining surface is formed by an inclined surface or a curved surface. A fluctuation generator of a fluctuation gear device as described in claim 2 or 6, wherein the second roller retainer is formed of resin or light metal. A fluctuation generator of a fluctuation gear device as described in claim 1 or 2, wherein a roller bearing is formed by the roller and the roller retainer. A fluctuation generator of a fluctuation gear device as described in claim 1 or 2, wherein a roller bearing is formed by the roller, the roller retainer and the flexible outer ring. The oscillation generator of the oscillating gear device as described in claim 1 or 2, wherein the roller bearing is formed by at least the roller, the roller retainer and the flexible inner ring. A fluctuating gear device comprises: an inner gear; an outer gear which is flexible and arranged on the inner circumference of the inner gear; and a fluctuation generator of the fluctuating gear device as described in any one of claims 1 to 10, arranged on the inner circumference of the outer gear.

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