JP7365766B2 - Eccentric swing type reduction gear - Google Patents

Description

The present invention relates to an eccentric rocking type speed reduction device.

Conventional eccentric oscillation type reduction gears consist of an external gear that performs eccentric oscillation by an eccentric body installed on the input shaft, an internal gear that meshes with the external gear, and a plurality of internal gears arranged along the circumference. It includes a first carrier and a second carrier connected to an external gear via a pin.
One end of the plurality of inner pins is supported by the first carrier, and the other end is inserted and supported by the second carrier.
The external gear is set to have a smaller number of teeth than the internal teeth of the internal gear, and when the input shaft rotates, the external gear swings eccentrically and rotates in a direction opposite to the input shaft according to the difference in the number of teeth. The structure is such that rotation occurs in the direction, and decelerated rotation due to this rotation is transmitted to the first carrier and the second carrier by the inner pin (see, for example, FIG. 3 of Patent Document 1).

JP 2017-82993 Publication

However, since the above-mentioned conventional eccentric swing type reduction gear uses a metal round bar as the inner pin, the shape of the axis-perpendicular cross section of the insertion end inserted into the second carrier side is limited to a circular shape. A problem has arisen in that the degree of freedom in designing the structure around the inner pin is low.

An object of the present invention is to provide an eccentric oscillation type speed reduction device with a high degree of freedom in designing the structure around the inner pin.

The present invention
internal gear,
an external gear that meshes with the internal gear;
an eccentric body shaft having an eccentric body that swings the external gear;
a first carrier and a second carrier that are synchronized with the rotation component of the external gear by a plurality of inner pins;
In an eccentric rocking type reduction gear equipped with
The plurality of inner pins are made of resin, one end is integrally formed with the first carrier, and the other end is inserted into the second carrier,
A cross-sectional shape perpendicular to the insertion direction at an insertion end portion, which is a portion of the plurality of inner pins inserted into the second carrier, is non-circular;
The second carrier is formed with a plurality of insertion holes into which insertion ends of the plurality of inner pins are inserted,
A cross-sectional shape of the insertion end of the inner pin in the insertion hole perpendicular to the insertion direction is equal to the insertion end of the inner pin,
The plurality of inner pins are arranged so as to be lined up on the circumference,
The cross-sectional shape of the insertion end of the plurality of inner pins individually circumscribes the cross-section of the insertion end of the plurality of inner pins and touches all the vertices of the cross-section, or For all of the plurality of end circumscribed circles that overlap and touch the arc portion of the cross-sectional shape, all The second circumscribed circle circumscribing the radially outer end of the internal gear in the cross-sectional shape of the insertion end of the inner pin is smaller.
In addition, other inventions include
internal gear,
an external gear that meshes with the internal gear;
an eccentric body shaft having an eccentric body that swings the external gear;
a first carrier and a second carrier that are synchronized with the rotation component of the external gear by a plurality of inner pins;
In an eccentric rocking type reduction gear equipped with
The plurality of inner pins are made of resin, one end is integrally formed with the first carrier, and the other end is inserted into the second carrier,
A cross-sectional shape perpendicular to the insertion direction at an insertion end portion, which is a portion of the plurality of inner pins inserted into the second carrier, is non-circular;
The second carrier is formed with a plurality of insertion holes into which insertion ends of the plurality of inner pins are inserted,
A cross-sectional shape of the insertion end of the inner pin in the insertion hole perpendicular to the insertion direction is equal to the insertion end of the inner pin,
The plurality of inner pins have the insertion end portion and a main body portion loosely inserted into the inner pin hole of the external gear,
comprising a bearing that supports the first carrier and a bearing that supports the second carrier,
The bearing that supports the second carrier overlaps the insertion end of the plurality of inner pins when viewed from the radial direction of the internal gear, and the bearing that supports the second carrier overlaps the insertion end of the plurality of inner pins when viewed from the radial direction of the internal gear, and This is an overlapping arrangement when viewed from the axial direction of the gear.

According to the present invention, it is possible to provide an eccentric oscillation type speed reduction device with a high degree of freedom in designing the periphery of the inner pin and the structure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view along the axial direction of an eccentric rocking type speed reduction device according to a first embodiment of the present invention. FIG. 2 is an axially perpendicular cross-sectional view of the eccentric rocking type speed reduction device taken along the line WW in FIG. 1. FIG. FIG. 2 is an axially perpendicular cross-sectional view of the eccentric rocking type speed reduction device taken along line XX in FIG. 1; FIG. 3 is a cross-sectional view showing an axially perpendicular cross section of the insertion end of the inner pin. FIG. 7 is an explanatory diagram showing details of the cross-sectional shape of an axis-perpendicular cross-section of the insertion end of the inner pin. FIG. 7 is a cross-sectional view showing another example (1) of the cross-sectional shape of the insertion end of the inner pin. FIG. 7 is a cross-sectional view showing another example (2) of the cross-sectional shape of the insertion end of the inner pin. FIG. 7 is a cross-sectional view showing another example (3) of the cross-sectional shape of the insertion end of the inner pin. FIG. 7 is a cross-sectional view showing another example (4) of the cross-sectional shape of the insertion end of the inner pin. FIG. 7 is a cross-sectional view showing another example (5) of the cross-sectional shape of the insertion end of the inner pin.

[Outline of embodiments of the invention]
Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view along the axial direction of an eccentric rocking type speed reducer 10 according to an embodiment of the present invention (a cross-sectional view taken along the line VV in FIG. 2), and FIG. 2 is a cross-sectional view taken along the line WW in FIG. FIG. 3 is an axially perpendicular sectional view of the eccentric rocking type reduction gear along the line XX in FIG. 1. FIG.
In this embodiment, the direction along the rotation axis O1 of the eccentric rocking type reduction gear 10 is referred to as the axial direction, the direction along the radius of a circle centered on the rotation axis O1 is referred to as the radial direction, and the direction centered on the rotation axis O1 is referred to as the radial direction. The direction of rotation is defined as the circumferential direction.
Note that the rotation axis O1 coincides with the central axis of an eccentric shaft 40, which will be described later.

The eccentric oscillation type reduction gear 10 has an eccentric body shaft including an internal gear 20, a first cover member 21, a second cover member 22, a first external gear 31, a second external gear 32, and eccentric bodies 41 and 42. 40, first and second carriers 51 and 52, and a plurality of inner pins 53.

The first and second external gears 31 and 32 mesh with the internal gear 20 while being eccentrically oscillated by the eccentric bodies 41 and 42 of the eccentric body shaft 40, respectively.
The output of the eccentric oscillating speed reduction device 10 is extracted from the first and second carriers 51 and 52 as rotation components of the first and second external gears 31 and 32.

[Eccentric shaft]
The eccentric shaft 40 located at the center of the eccentric oscillating speed reduction device 10 is hollow over its entire length, and one end of the eccentric shaft 40 has an input port for receiving torque from a power source such as a motor. A gear 43 is attached.
When rotation is input from the input gear 43, rotation is output from the first and second carriers 51 and 52 at an output rotation speed smaller than the input rotation speed.
In the following explanation, the direction along the rotation axis O1 and in which the input gear 43 is attached to the eccentric shaft 40 will be referred to as the "input side" (the right side in FIG. 1), and the opposite direction will be referred to as the "input side" (the right side in FIG. 1). It is assumed to be the "output side" (the left side in FIG. 1).
However, this definition is for convenience of explanation, and the input side and output side are not limited to the above definitions.

One end and the other end of the eccentric shaft 40 are rotatably supported by the first carrier 51 and the second cover member 22 via eccentric shaft bearings 47 and 48, each of which is a radial ball bearing.
The first carrier 51 is provided with a step-shaped fitting part 511 on the inner circumference, and the outer ring of the eccentric shaft bearing 47 is fitted into the fitting part 511 by a so-called spigot fitting structure.
Further, in the opening 222 formed in the center of the second cover member 22, a substantially annular stopper 46 that fits into an inner circumferential groove formed on the inner circumferential surface is adjacent to the eccentric body shaft bearing 48. It is provided.
The eccentric body shaft bearings 47 and 48 are provided on both sides of the eccentric body shaft 40 so as to sandwich the eccentric bodies 41 and 42 therebetween.
With these structures, the eccentric shaft 40 is positioned via the eccentric shaft bearings 47 and 48 so that it does not move in the direction along the rotation axis O1.
Note that the eccentric shaft bearings 47 and 48 are not limited to radial ball bearings, and other bearings may be used.

Moreover, two eccentric bodies 41 and 42 are integrally provided on the eccentric body shaft 40 in line with each other along the rotation axis O1 with a phase difference of 180 degrees around the rotation axis O1.
And between the first and second external gears 31, 32 and the eccentric bodies 41, 42, eccentric body bearings 44, 45 made of radial ball bearings are arranged, respectively. The eccentric bodies 41 and 42 of the eccentric body shaft 40 rotate synchronously, and the first and second external gears 31 and 32 are rotated through the eccentric bodies 41 and 42 of the eccentric body shaft 40 that rotate synchronously and eccentrically. They mesh with the internal gears 20 while eccentrically swinging.
Note that the eccentric body bearings 44 and 45 are not limited to radial ball bearings, and other bearings may be used.

[External gear]
The first external gear 31 is incorporated into the eccentric body 41 via an eccentric body bearing 44, and swings as the eccentric body shaft 40 rotates.
The second external gear 32 is incorporated into the eccentric body 42 via an eccentric body bearing 45, and swings in a phase different from that of the first external gear 31 as the eccentric body shaft 40 rotates.
The first external gear 31 is provided with a plurality of inner pin holes 311 through which the plurality of inner pins 53 are respectively passed, spaced apart from each other in the circumferential direction. Similarly, the second external gear 32 is provided with a plurality of inner pin holes 321 through which the plurality of inner pins 53 pass respectively, spaced apart from each other in the circumferential direction.

[Internal gear]
The internal gear 20 is integrally formed with the first cover member 21, and has a plurality of internal teeth formed in line along the circumferential direction on the inner peripheral portion of the input side end of the first cover member 21. It is equipped with
The plurality of internal teeth of the internal gear 20 have a tooth width that is twice or more of the first and second external gears 31 and 32 in the axial direction, and the first external gear 31 and the second external gear arranged in the axial direction It can mesh with both external teeth of the external gear 32.
Note that the rotation axis (center axis) of this internal gear 20 is on the same line as the rotation axis O1.

[Cover member]
The first cover member 21 is formed into a substantially cylindrical shape, and accommodates the first carrier 51, the first and second external gears 31 and 32, and the output side end of the eccentric shaft 40 inside thereof.
The first cover member 21 supports the first carrier 51 rotatably around the rotation axis O1 via a main bearing 23 made of a radial ball bearing at the inner peripheral portion on the output side. The main bearing 23 is fitted in such a manner that it abuts against a fitting part 211 having a stepped structure formed on the inner periphery of the first cover member 21 . Furthermore, a substantially annular stopper 26 that fits into an inner circumferential groove formed on the inner circumferential surface is provided on the inner circumferential portion of the first cover member 21 adjacent to the main bearing 23 . Thereby, the main bearing 23 is positioned and fixed so that it does not move in the axial direction.

The second cover member 22 is formed into a substantially cylindrical shape whose input side end is closed by a closing wall surface 221, and accommodates the second carrier 52 and the input side end of the eccentric shaft 40 inside thereof. .
The second cover member 22 has an opening 222 formed in the center of a closed wall surface 221 on the input side. As described above, this opening 222 is provided with an eccentric shaft bearing 48 that rotatably supports the other end of the eccentric shaft 40. I support it.

Near the outer periphery of the second cover member 22, a plurality of insertion holes 223 for bolts B, which are connecting members, are formed at uniform intervals along the circumferential direction. A plurality of screw holes 212 are formed on the input side end surface of the first cover member 21, and by fastening the plurality of bolts B, the second cover member 212 is formed on the input side end of the first cover member 21. can be fixed.

Note that a stepped portion 213 whose diameter is reduced over the entire circumference is formed on the outer periphery of the input side end of the first cover member 21, and a first step portion 213 is formed on the output side end of the second cover member 22. A peripheral wall portion 224 extending toward the cover member 21 side is provided.
The step portion 213 can be inserted and fitted into the peripheral wall portion 224 . That is, a spigot fitting structure is also formed between the first cover member 21 and the second cover member 22. As a result, when the first cover member 21 and the second cover member 22 are fitted together, they are mutually positioned so that the center axis of the first cover member 21 and the center axis of the second cover member 22 are on the same axis. be able to.

Further, the second cover member 22 rotatably supports the second carrier 52 around the rotation axis O1 via a main bearing 24 made of a radial ball bearing at its inner peripheral portion. The main bearing 24 is fitted into the inner peripheral portion of the second cover member 22 in a state where it abuts against the closing wall surface 221.
Further, the second carrier 52 has a flange portion 521 that contacts the main bearing 24 from the output side. Therefore, within the second cover member 22, the second carrier 52 is positioned with high precision in the direction along the rotation axis O1 via the main bearing 24.
Note that the main bearings 23 and 24 are not limited to radial ball bearings, and other bearings may be used.

[Career]
The first carrier 51 and the second carrier 52 are arranged on the output side and the input side in the axial direction with the first and second external gears 31 and 32 in between.
In the first and second carriers 51 and 52, the insertion ends 532 of the plurality of inner pins 53 (for example, six) provided integrally with the first carrier 51 around the eccentric body shaft 40 are connected to the second carrier 52. are inserted into the insertion holes 522 of and connected to each other.
The longitudinal direction of each inner pin 53 is parallel to the axial direction, and the insertion direction of the insertion end portion 532 is also parallel to the axial direction.

The first carrier 51 is rotatably supported by the first cover member 21 via the main bearing 23 . The inner ring of the main bearing 23 is fitted onto the outer periphery of the output side end of the first carrier 51 so as to abut against a fitting part 512 having a stepped structure. Further, the first carrier 51 is provided adjacent to the main bearing 23 with a substantially annular stopper 25 that fits into an outer circumferential groove formed on the outer circumferential surface of the output side end. Thereby, the first carrier 51 is positioned and fixed with respect to the main bearing 23 so as not to move in the axial direction. Therefore, the first carrier 51 is accurately positioned in the axial direction via the main bearing 23.

The second carrier 52 is an annular body with a wide opening at the center, and as described above, the outer circumference thereof is supported by the main bearing 24 so as to be rotatable around the rotation axis O1.
Insertion holes 522 into which insertion ends 532 of inner pins 53 are inserted are formed through the second carrier 52 in the axial direction at uniform intervals along the circumferential direction.

[Inner pin]
The plurality of inner pins 53 are cylindrical bodies extending parallel to the axial direction from the first carrier 51 toward the input side.
Each inner pin 53 is inserted into a main body portion 531 whose axially perpendicular cross section (a cross section perpendicular to the insertion direction of the insertion end portion 532) is circular with a uniform outer diameter, and an insertion hole 522 of the second carrier 52. and an insertion end 532.
The insertion end 532 is located at the input side end of the main body 531, and has a non-circular cross section perpendicular to the axis (a cross section perpendicular to the insertion direction of the insertion end 532).

Furthermore, a cylindrical inner roller 54 is rotatably fitted around the outer periphery of the main body portion 531 of each inner pin 53 .
Each inner pin 53 is loosely inserted into the inner pin holes 311 and 321 of the first and second external gears 31 and 32 via an inner roller 54.
Note that during operation, at least a portion of the outer circumference of the main body portion 531 of the inner pin 53 is in contact with the inner pin holes 311 and 321 via the inner roller 54.

[Materials of each component]
Of the above-mentioned components, at least the inner pin 53 of the eccentric swing type speed reduction device 10 is made of resin. As this resin material, a material having high strength such as FRP (Fiber-Reinforced Plastic) or CFRP (Carbon Fiber Reinforced Plastic) can be used. However, the resin material of the inner pin 53 is not limited to this, and various materials may be used, such as various resins that are a single material, and composite materials that are a composite of resin and another material.

In addition, configurations other than the above, for example, the first carrier 51, the second carrier 52, the first cover member 21, the second cover member 22, the internal gear 20, the eccentric body shaft 40 including the eccentric bodies 41 and 42, the first The external gear 31, the second external gear 32, and the inner roller 54 are also made of resin. As these resin materials, various materials such as FRP, CFRP, paper baking material, cloth baking material, and resin as a single material may be applied.

Note that, as described above, since the first carrier 51 and the inner pin 53 are integrally formed, they are formed of the same material, but are not limited to this. The first carrier 51 and the inner pin 53 may be formed separately and from different materials.
Also, excluding the inner pin 53, the first carrier 51, the second carrier 52, the first cover member 21, the second cover member 22, the internal gear 20, the eccentric body shaft 40 including the eccentric bodies 41 and 42, the first outer The gear 31, the second external gear 32, and the inner roller 54 may be made of a material other than resin, such as aluminum, aluminum alloy, magnesium alloy, or other metal.

The bolts B and the bearings 23, 24, 44, 45, 47, and 48 are made of metal, but they may also be made of resin such as FRP and CFRP.
Further, the bearings 23, 24, 44, 45, 47, and 48 are not limited to ball bearings, and sliding bearings can be used.

[Cross-sectional shape of the insertion end of the inner pin]
As described above, since the inner pin 53 is made of resin, the insertion end portion 532 can be formed into a wide variety of cross-sectional shapes by molding.
The shape of the axially perpendicular cross section of the insertion end 532 of the inner pin 53 will be described in detail with reference to FIGS. 3 to 5. 4 is a sectional view showing an axially perpendicular cross section of the insertion end 532 of the inner pin 53, and FIG. 5 is a cross-sectional view of the axially perpendicular cross section of the insertion end 532 of the inner pin 53 (hereinafter referred to as "cross-sectional shape of the insertion end 532") FIG.

The cross-sectional shape of the insertion end 532 of each inner pin 53 is non-circular, as shown in FIG. Further, the cross-sectional shape of the insertion end portion 532 is a first circumscribed circle that further circumscribes all of the plurality of end circumscribed circles C0 that individually circumscribe the cross-sectional shape of the insertion end portion 532 of the plurality of inner pins 53. A second circumscribed circle C2 that circumscribes the cross-sectional shapes of the insertion ends 532 of all the inner pins 53 is smaller than C1.
Note that both the first circumscribed circle C1 and the second circumscribed circle C2 are circles centered on the rotation axis O1.
In addition, the radius of the second circumscribed circle C2 is determined by the cross section of the insertion end 532 in the direction perpendicular to the line segment connecting the rotation axis O1 and the center of the end circumscribed circle C0 (the tangential direction of the second circumscribed circle C2). It may be a diameter that provides the maximum width of the shape (the diameter of the end circumscribed circle C0).

For example, as an example of the cross-sectional shape of the insertion end portion 532 that satisfies the above-mentioned requirements, as shown in FIG. An example of this is a shape cut along an arc. That is, the cross-sectional shape of the insertion end portion 532 is such that the outer portion M in the radial direction has an arc shape centered on the rotation axis O1.
In addition, in FIG. 4, C3 is a third circle centered on the rotation axis O1 that passes through the center c of the end circumscribed circle C0.
Further, the radius of the second circumscribed circle C2 is smaller than the radius of the first circumscribed circle C1, and larger than the value obtained by subtracting the diameter of the end circumscribed circle C0 from the radius of the first circumscribed circle C1. Further, if the radius of the second circumscribed circle C2 is smaller than the radius of the first circumscribed circle C1 and larger than the value obtained by subtracting the radius of the end circumscribed circle C0 from the radius of the first circumscribed circle C1, the maximum width in the tangential direction (=diameter of end circumscribed circle C0) is easy to obtain.

Note that when the insertion end 532 has the cross-sectional shape shown in FIG. 4, the end circumscribed circle C0 matches the circular axial cross-sectional shape of the main body 531 of the inner pin 53 when viewed from the axial direction. Although such a configuration facilitates molding, this is not an essential requirement.

Further, in this embodiment, the axially perpendicular cross-sectional shape of the main body portion 531 (the cross-sectional shape perpendicular to the insertion direction of the insertion end portion 532) is circular, and the end circumscribed circle C0 of the insertion end portion 532 when viewed from the axial direction. The inner pins 53 are shown as an example of overlapping inner pins 53 in a state in which the inner pins 53 overlap with each other.
Further, as shown in FIG. 5, the body circumscribed circles C5 circumscribing the axis-perpendicular cross-sectional shape of the body 531 of all the inner pins 53 overlap with the first circumscribed circle C1 when viewed from the axial direction. This example illustrates a case where the second circumscribed circle C2 described above is inside the body circumscribed circle C5.
However, these two requirements are not essential.

When the cross-sectional shape of the insertion end 532 is determined so that the diameter of the second circumscribed circle C2 is smaller than the first circumscribed circle C1, space is saved in the radially outer portion of the insertion end 532 of each inner pin 53. This makes it possible to reduce the size of the entire device in the radial direction. Further, the same can be said when the cross-sectional shape of the insertion end portion 532 is determined so that the second circumscribed circle C2 is inside the body portion circumscribed circle C5.
For example, as shown in FIG. 1, the main bearing 24 is provided on the radially outer side of the insertion end 532 of each inner pin 53. As the diameter of the second circumscribed circle C2 becomes smaller, the main bearing 24 becomes smaller. Bearings with a smaller diameter can be used. Accordingly, one end of the eccentric rocking speed reduction device 10, for example, the end on the input side, can be made smaller in diameter and smaller overall.

In addition, each inner pin 53 has a function of transmitting torque from the first and second external gears 31 and 32 to the first and second carriers 51 and 52, and when the eccentric oscillating speed reduction device 10 is operated, the inner pins 53 are arranged in the radial direction. shear stress is applied.
On the other hand, in the cross-sectional shape of the insertion end portion 532 shown in FIG. 4, the width W1 in the tangential direction (direction perpendicular to the radial direction) of the second circumscribed circle C2 is wider than the radial width W2. , it is possible to obtain high rigidity against the above-mentioned shear stress.
In particular, when the width in the tangential direction of the second circumscribed circle C2 of the cross-sectional shape is made equal to the diameter of the end circumscribed circle C0 (maximum width), higher rigidity can be obtained. The requirement for obtaining this maximum width is that the second circumscribed circle C2 is radially larger than the two intersection points P1 and P2 where the tangent L1 of the third circle C3 at the center c of the end circumscribed circle C0 intersects with the end circumscribed circle C0. It is to be outside of.

Further, another example (1) of the cross-sectional shape of the insertion end portion 532 that satisfies the requirements shown in FIG. 5 is shown in FIG.
The cross-sectional shape of the insertion end 532 shown in FIG. 6 is obtained by cutting out the inner part in the radial direction centering on the rotation axis O1 along the arc of the fourth circle C4 from the cross-sectional shape of the insertion end 532 shown in FIG. It has a shape. The radius of the fourth circle C4 should be smaller than the radius of the second circumscribed circle C2.
In the case of the cross-sectional shape of the insertion end 532 shown in FIG. 6, in addition to the same effect as the cross-sectional shape shown in FIG. 4, the inner area of the insertion end 532 of each inner pin 53 can also save space. There are advantages.

Further, another example (2) of the cross-sectional shape of the insertion end portion 532 that satisfies the requirements shown in FIG. 5 is shown in FIG.
Although the cross-sectional shape of the insertion end portion 532 shown in FIG. 4 has a radially outer portion along the second circumscribed circle C2, the cross-sectional shape only needs to be circumscribed to the second circumscribed circle C2, and FIG. As shown in , the outer portion M in the radial direction may have a shape other than a circular arc shape, for example, a linear shape. Note that the linear shape here is a tangent to a circular arc along the second circumscribed circle C2, and is a tangent line between the rotation axis O1 and the end circumscribed circle C0 (or a circular cross-sectional shape perpendicular to the axial direction of the main body portion 531). Indicates the shape of a straight line perpendicular to the line segment connecting the centers of. In the following description, this linear shape will be referred to as an "orthogonal linear shape" for convenience.
Similarly, as shown in FIG. 6, when cutting the inner part in the radial direction centering on the rotation axis O1, a shape other than the arc shape along the fourth circle C4, for example, parallel to an orthogonal linear shape. It may also be a straight line shape.
Even in the case of the cross-sectional shape of the insertion end portion 532 shown in the other example (2) of FIG. 7, the same effect as the cross-sectional shape of FIGS. 4 and 6 can be obtained.

Further, another example (3) of the cross-sectional shape of the insertion end portion 532 that satisfies the requirements shown in FIG. 5 is shown in FIG.
The cross-sectional shape of the insertion end portion 532 shown in FIG. 4 is such that both sides in the circumferential direction follow the end circumscribed circle C0, but the cross-sectional shape only needs to be circumscribed to the end circumscribed circle C0; 8, the both sides of the circumferential direction have a shape other than a circular arc, for example, a line connecting the center of the rotation axis O1 and the end circumscribed circle C0 (or a circular cross-sectional shape perpendicular to the axial direction of the main body 531). It may also be a straight line shape parallel to the minute.
Furthermore, as is common to the examples of the cross-sectional shape of the insertion end portion 532 shown in FIGS. 4, 6, and 7, the end circumscribed circle C0 is the axial cross-sectional shape of the main body portion 531 of the inner pin 53. It doesn't have to match.
However, if the end circumscribed circle C0 is made larger than the axial cross-sectional shape of the main body portion 531 of each inner pin 53, the space of the outer portion in the radial direction than the insertion end portion 532 of each inner pin 53 can be utilized or miniaturized. Since there are more restrictions on the cross-sectional shape to obtain the effect, it is advantageous to make the diameter of the end circumscribed circle C0 equal to or smaller than the axial cross-sectional shape of the main body portion 531 of the inner pin 53, as shown in FIG. It is.

Another example (4) of the cross-sectional shape of the insertion end portion 532 that satisfies the requirements shown in FIG. 5 is shown in FIG. 9, and another example (5) is shown in FIG.
It is possible to satisfy the requirements shown in FIG. 5, save space in a radially outer portion of each inner pin 53 than the insertion end 532, and downsize the entire device in the radial direction. If a wide width in the circumferential direction of the cross-sectional shape of 532 can be ensured, a wide variety of shapes can be selected for the shape itself, as shown in other examples (4) and (5). It may be a polygon such as a substantially fan shape as in another example (4) or a regular pentagon as in another example (5).
Further, as shown in these other examples (4) and (5), the end circumscribed circle C0 may be eccentric with respect to the axial cross-sectional shape of the main body portion 531 of the inner pin 53. Note that the eccentricity of the end circumscribed circle C0 is not limited to these other examples (4) and (5), but also applies to the example in FIG. 4 already explained and other examples (1) to (3). be.

[Rotational operation of eccentric swing type reduction gear]
Next, the rotational operation of the eccentric rocking type speed reduction device 10 will be explained.
For example, when rotation is input from the eccentric shaft 40, the eccentrics 41 and 42 integrally attached to the eccentric shaft 40 rotate, and the first and second external gears 31 and 32 While inscribed in the gear 20, each of them oscillates and rotates while maintaining a phase difference of 180 degrees.
The number of teeth of the first and second external gears 31 and 32 is at least one less than the number of teeth of the internal gear 20. Therefore, when the internal gear 20 is in a non-rotating state, the first and second external gears 31 and 32 rotate by the difference in the number of teeth for each rotation of the eccentric shaft 40.
The rotations of the first and second external gears 31 and 32 are transmitted to the first and second carriers 51 and 52 via the plurality of inner pins 53 and output as decelerated rotation.
Note that it is also possible to fix the first and second carriers 51 and 52 so that they do not rotate, and to extract the decelerated rotation from the internal gear 20, the first cover member 21, and the second cover member 22.

[Relationship between the inner pin and the main bearing of the second carrier]
The main bearing 24 that supports the second carrier 52 is arranged to overlap the insertion end 532 of each inner pin 53 when viewed from the radial direction. That is, as shown in FIG. 1, the main bearing 24 is located on the radially outer side of the insertion end portion 532, and overlaps with the insertion end portion 532 in the axial direction.
Further, the main bearing 24 is arranged to overlap the main body portion 531 of each inner pin 53 when viewed from the axial direction. That is, as shown in FIG. 3, the main bearing 24 and the main body portion 531 overlap in the radial direction.
As shown in these figures, the inner diameter of the main bearing 24 is smaller than the circumscribed circle C5 of the main body 531 of each inner pin 53, and is radially outer than the insertion end 532 of each inner pin 53. This portion is utilized as a space for arranging the main bearing 24, thereby reducing the size of the entire device in the radial direction.

[Technical effects of embodiments of the invention]
In the eccentric rocking speed reduction device 10, the plurality of inner pins 53 are made of resin, and the axially perpendicular cross-sectional shape of the insertion end 532 of each inner pin 53 is non-circular.
When the inner pin 53 is made of resin, it is less subject to processing restrictions, and even if a variety of cross-sectional shapes are selected, it can be formed relatively easily by processing such as molding.
On the other hand, if the cross-sectional shape of the insertion end of the inner pin 53 is circular, for example, a space corresponding to the diameter of the circular cross-section of the insertion end of the inner pin 53 is necessarily required in the radial direction, which increases the freedom of design. is limited.
On the other hand, if the cross-sectional shape of the insertion end 532 is non-circular, it is possible to take measures such as matching the shape of the surplus space of the configuration on the inserted side, greatly improving the degree of freedom in design. becomes possible.

Furthermore, the cross-sectional shapes of the insertion ends of the inner pins 53 shown in FIGS. The second circumscribed circle C2 that circumscribes the cross-sectional shape of the insertion end of all the inner pins 53 is smaller than the first circumscribed circle C1 that further circumscribes all of the end circumscribed circle C0. There is.
In this case, the eccentric rocking type speed reduction device 10 has the following advantageous effects.
By making the diameter of the second circumscribed circle C2 smaller than the first circumscribed circle C1, it is possible to save space in the radially outer portion of the insertion end 532 of each inner pin 53, and the space can be used for other purposes. The entire device can be downsized in the radial direction depending on the arrangement of the members and the diameter of the second circumscribed circle C2.
In addition, with the above cross-sectional shape, the cross-sectional shape of the insertion end 532 of the inner pin 53 is not easily constrained in the circumferential direction, so that the inner pin 53 has high rigidity against stress in the circumferential direction that occurs in the inner pin 53 during rotation. It is possible to make it into a shape.

In addition, the eccentric rocking type speed reduction device 10 has a requirement that the second circumscribed circle C2 is inside the main body circumscribed circle C5 that circumscribes all the cross-sectional shapes of the main body 531 of all the inner pins 53. It is also equipped with
Even when this requirement is met, the space around the insertion end 532 of each inner pin 53 can be saved, the device can be downsized, and the insertion end 532 can be made highly rigid against circumferential stress generated in the inner pin 53. Effects such as shaping can be obtained.
In addition, in the eccentric rocking type speed reduction device 10, the inner pin 53 has an end circumscribed circle C0 of the insertion end 532 that coincides with the circular cross-sectional shape of the main body 531, or It is inside. This case also contributes to saving space around the insertion end 532 of each inner pin 53 and downsizing the device.

Furthermore, in each of the cross-sectional shapes of the insertion end 532 of the inner pin 53 shown in FIGS. positioned. Note that the "center of gravity on a figure" refers to the center of mass when mass is uniformly distributed on the figure (cross-sectional shape).
In other words, the cross-sectional shapes of the insertion ends 532 of the inner pins 53 are all closer to the inside in the radial direction, which saves space in the outer part in the radial direction than the insertion ends 532 of the inner pins 53. This makes it possible to utilize the space or to reduce the size in the radial direction.

Further, in each of the cross-sectional shapes of the insertion end portion 532 of the inner pin 53 shown in FIGS. 4 and 6 to 10, the width in the tangential direction of the circumference perpendicular to the radial direction is wider than the width in the radial direction. It has become.
Therefore, space is saved in the outer part in the radial direction, and while the space is utilized or the size is reduced in the radial direction, the shape is highly rigid against the circumferential stress generated in the inner pin 53 during rotation. It is possible to do so.

Further, in each of the cross-sectional shapes of the insertion end portion 532 of the inner pin 53 shown in FIGS. 4 and 6 to 10, the outer portion in the radial direction has a circular arc shape centered on the rotation axis O1 or an orthogonal linear shape. Therefore, space can be saved in the radially outer portion of the insertion end of the plurality of inner pins 53, and it is possible to form a shape with high rigidity against circumferential stress generated in the inner pins 53 during rotation. It is.

Furthermore, in the eccentric rocking type reduction gear device 10, the second carrier 52 into which the insertion end 532 of each inner pin 53 is inserted is supported by the main bearing 24, but the cross section of the insertion end 532 of each inner pin 53 is Since the shape is as shown in FIGS. 4 and 6 to 10, the main bearing 24 can be downsized, and the end portion where the second carrier 52 of the eccentric oscillating speed reduction device 10 is placed can be downsized. It becomes possible to aim for.

[others]
The details shown in each of the above embodiments can be changed as appropriate without departing from the spirit of the invention.
For example, although the second carrier 52 is rotatably supported by the main bearing 24, the second carrier 52 may be provided in the eccentric rocking type reduction gear in a state where it is not supported by other members.
For example, the second carrier is formed into an annular shape, and an insertion hole into which the insertion end of each inner pin 53 is inserted is formed. The second carrier may be disposed inside the first cover member 21 and the second cover member 22 so as to be in sliding contact with other members, or may be disposed in a non-contact state with other members.
In this structure as well, the second carrier holds the insertion ends 532 of each inner pin 53 at a constant interval in the circumferential direction, prevents the ends on the first carrier side from falling in the circumferential direction, and It is possible to maintain high rigidity of the pin 53.

Further, the first carrier 51 and each inner pin 53 may be formed from separate members. In that case, each inner pin 53 may be fitted into the first carrier 51 with the same fitting structure as the second carrier 52 described above.
In addition, although the eccentric rocking type reduction gear 10 is illustrated in which the body circumscribed circle C5 and the first circumscribed circle C1 overlap so that they coincide when viewed from the axial direction, this is not an essential requirement; 1. It is not necessary to coincide with or overlap with the circumscribed circle C1.

Further, in the above embodiment, a so-called center crank type eccentric rocking speed reduction device is shown in which one eccentric body shaft is arranged at the axis of the speed reduction device. However, the present invention may be applied to a so-called distributed type eccentric rocking speed reduction device in which two or more eccentric body shafts are arranged offset from the axis of the speed reduction gear.
Further, in the above embodiment, the first external gear 31 and the second external gear 32 are shown as external gears, but the number of external gears may be one or three or more. .

10 Eccentric oscillation type reduction gear 20 Internal gear 21 First cover member 22 Second cover member 24 Main bearings 25, 26 Clasp 31 First external gear 32 Second external gear 40 Eccentric body shafts 41, 42 Eccentric body 43 Input gears 44, 45 Bearing for eccentric body 46 Clamps 47, 48 Bearing for eccentric body shaft 51 First carrier 52 Second carrier 53 Inner pin 54 Inner roller 211 Fitting part 212 Screw hole 213 Step part 221 Closed wall surface 222 Opening Part 223 Insertion hole 224 Peripheral wall part 311 Inner pin hole 311, 321 Inner pin hole 511, 512 Fitting part 521 Flange part 522 Insertion hole 531 Main body part 532 Insertion end part B Bolt c Center C0 End circumscribed circle C1 First circumscribed circle C2 Second circumscribed circle C3 Third circle C4 Fourth circle g Center of gravity L1 Tangent line O1 Axis of rotation P1, P2 Intersection

Claims (8)

internal gear,
an external gear that meshes with the internal gear;
an eccentric body shaft having an eccentric body that swings the external gear;
a first carrier and a second carrier that are synchronized with the rotation component of the external gear by a plurality of inner pins;
In an eccentric rocking type reduction gear equipped with
The plurality of inner pins are made of resin, one end is integrally formed with the first carrier, and the other end is inserted into the second carrier,
A cross-sectional shape perpendicular to the insertion direction at an insertion end portion, which is a portion of the plurality of inner pins inserted into the second carrier, is non-circular;
The second carrier is formed with a plurality of insertion holes into which insertion ends of the plurality of inner pins are inserted,
A cross-sectional shape of the insertion end of the inner pin in the insertion hole perpendicular to the insertion direction is equal to the insertion end of the inner pin,
The plurality of inner pins are arranged so as to be lined up on the circumference,
The cross-sectional shape of the insertion end of the plurality of inner pins individually circumscribes the cross-section of the insertion end of the plurality of inner pins and touches all the vertices of the cross-section, or For all of the plurality of end circumscribed circles that overlap and touch the arc portion of the cross-sectional shape, all The eccentric oscillation type speed reduction device has a shape in which a second circumscribed circle circumscribing the radially outer end of the internal gear in the cross-sectional shape of the insertion end of the inner pin is smaller. The plurality of inner pins are arranged so as to be lined up on the circumference,
The plurality of inner pins are
In either case, the center of gravity of the cross-sectional shape of the insertion end circumscribes the cross-sectional shape of the insertion end and touches all vertices of the cross-sectional shape, or touches an arc portion of the cross-sectional shape. The eccentric oscillation type speed reduction device according to claim 1 , wherein the eccentric oscillation type speed reduction device is located inside the internal gear in the radial direction from the center of the end circumscribed circles that overlap and touch. The cross-sectional shape of the insertion end of the plurality of inner pins is
The eccentric oscillating speed reduction device according to claim 1 or 2, wherein the internal gear has a width in a direction perpendicular to the radial direction that is wider than a width in the radial direction. The cross-sectional shape of the insertion end of the plurality of inner pins is
The outer portion of the internal gear in the radial direction has an arc shape concentric with the internal gear or a linear shape along a direction perpendicular to a line connecting the center of the internal gear and the center of the inner pin. The eccentric rocking type speed reduction device according to any one of claims 1 to 3 . The plurality of inner pins have the insertion end portion and a main body portion loosely inserted into the inner pin hole of the external gear,
comprising a bearing that supports the first carrier and a bearing that supports the second carrier,
The bearing that supports the second carrier overlaps the insertion end of the plurality of inner pins when viewed from the radial direction of the internal gear, and the bearing that supports the second carrier overlaps the insertion end of the plurality of inner pins when viewed from the radial direction of the internal gear, and The eccentric rocking type speed reduction device according to any one of claims 1 to 4, wherein the gears are arranged so as to overlap when viewed from the axial direction. internal gear,
an external gear that meshes with the internal gear;
an eccentric body shaft having an eccentric body that swings the external gear;
a first carrier and a second carrier that are synchronized with the rotation component of the external gear by a plurality of inner pins;
In an eccentric rocking type reduction gear equipped with
The plurality of inner pins are made of resin, one end is integrally formed with the first carrier, and the other end is inserted into the second carrier,
A cross-sectional shape perpendicular to the insertion direction at an insertion end portion, which is a portion of the plurality of inner pins inserted into the second carrier, is non-circular;
The second carrier is formed with a plurality of insertion holes into which insertion ends of the plurality of inner pins are inserted,
A cross-sectional shape of the insertion end of the inner pin in the insertion hole perpendicular to the insertion direction is equal to the insertion end of the inner pin,
The plurality of inner pins have the insertion end portion and a main body portion loosely inserted into the inner pin hole of the external gear,
comprising a bearing that supports the first carrier and a bearing that supports the second carrier,
The bearing that supports the second carrier overlaps the insertion end of the plurality of inner pins when viewed from the radial direction of the internal gear, and the bearing that supports the second carrier overlaps the insertion end of the plurality of inner pins when viewed from the radial direction of the internal gear, and Eccentric oscillation type reduction gear where the gears overlap when viewed from the axial direction . The plurality of inner pins are arranged so as to be lined up on the circumference,
The plurality of inner pins have the insertion end portion and a main body portion loosely inserted into the inner pin hole of the external gear,
Each of the inner pins has a circular cross-sectional shape perpendicular to the insertion direction of the main body,
The insertion end of all the inner pins with respect to the circumscribed circle of the main body circumscribing the radially outer end of the internal gear in the cross-sectional shape perpendicular to the insertion direction of the main body of all the inner pins. The eccentric oscillation type speed reduction device according to any one of claims 1 to 6, wherein a second circumscribed circle circumscribing a radially outer end of the internal gear in the cross-sectional shape is an inner side. An end circumscribed circle that individually circumscribes the insertion end and contacts all vertices of the cross-sectional shape of the insertion end, or overlaps and contacts an arc portion of the cross-sectional shape, has a circular cross-sectional shape of the main body. The eccentric rocking type speed reduction device according to claim 7 , which overlaps with or is located inside thereof.

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