JP2021134815A - Transmission device - Google Patents

Abstract

To easily attain downsizing and thinning so as to also contribute to reduction of cost and improvement of maintainability.SOLUTION: A transmission device 1 comprises: an input shaft which is rotated around an axis O1; an inner gear 4 which is disposed around an eccentric axis O2 which is eccentric with respect to the axis, and actuated with the rotation of the input shaft and includes a plurality of inner teeth 3 disposed while being spaced in a circumferential direction going around the eccentric axis; an outer gear 6 including a plurality of outer teeth 5 disposed in a rotatable manner around the axis and engageable to the plurality of inner teeth; an output shaft which is rotated around the axis with the rotation of the outer gear; and a guide member 70 which constrains the auto-rotation of the inner gear, thereby guiding the inner gear so as to eccentrically swing around the axis. The number of outer teeth is different from the number of inner teeth.SELECTED DRAWING: Figure 6

Description

The present invention relates to a transmission device.

Conventionally, as a transmission device that transmits the transmitted power, a speed reducer that reduces the rotational speed of the output shaft of the motor and outputs the speed has been known. Generally, a speed reducer is capable of decelerating the rotation speed of an output shaft by using a plurality of gears and outputting torque inversely proportional to the deceleration. As a speed reducer of this type, for example, in Patent Document 1 below, a speed reducer using an external gear that rotates eccentrically with the rotation of the input shaft is known.

The speed reducer described in Patent Document 1 includes an input shaft, an eccentric body that rotates by rotation of the input shaft, an external gear that is attached to the eccentric body and can rotate eccentrically, and an external gear that is fixed to a casing and has an external gear. It includes an internal gear that meshes internally and an output shaft that is connected to the external gear via a spline means that extracts and transmits only the rotation component of the external gear.
The external gear is arranged inside the internal gear in a state of being meshed with the internal gear, and is rotatable around an eccentric axis eccentric with respect to the central axis of the internal gear. The number of teeth of the external gear is formed one tooth less than the number of teeth of the internal gear.

According to the speed reducer described in Patent Document 1, when the input shaft rotates, the rotational force is transmitted to the external gear via the eccentric body. Since the rotation of the external gear is restricted by meshing with the internal gear, the external gear rotates eccentrically so as to swing around the eccentric axis while being inscribed in the internal gear. At this time, the external gear rotates eccentrically in a decelerated state depending on the relationship between the number of teeth of the external gear and the number of teeth of the internal gear. Then, since only the rotation component of the external gear can be taken out by the spline means and transmitted to the output shaft, the output shaft can be rotated in a decelerated state.

Japanese Patent No. 2686337

However, since the conventional speed reducer has a structure in which the external gear arranged inside the internal gear fixed to the casing is eccentrically rotated so as to swing, the external gear and the output shaft are connected. In between, it is necessary to provide spline means or the like for extracting only the rotation component of the external gear. Therefore, a space for providing a spline means or the like is required, and it is difficult to reduce the size and thickness of the speed reducer. Further, by providing the spline means or the like, the configuration becomes complicated and the number of parts increases, so that it is difficult to reduce the cost and the maintainability tends to decrease.

The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a transmission device that can be easily miniaturized and thinned, and can lead to cost reduction and improvement of maintainability. That is.

(1) The transmission device according to the present invention is arranged around an input shaft that is rotated around an axis by the transmitted power and an eccentric axis that is eccentric to the axis, and is arranged with the rotation of the input shaft. An internal gear having a plurality of internal teeth that operates and is arranged at intervals in the circumferential direction that orbits the eccentric axis is arranged so as to face the internal gear on one side in the axial direction. Along with this, an external gear that is rotatably arranged around the axis and has a plurality of external teeth that can mesh with the plurality of internal teeth, and an output shaft that rotates around the axis as the external gear rotates. The internal gear is fixed to a fixed plate arranged so as to face the internal gear on the other side in the axial direction, and by restraining the rotation of the internal gear, the internal gear swings eccentrically about the axis. A guide member for guiding the internal gear is provided, and the external teeth have a number of teeth different from the number of internal teeth.

According to the transmission device according to the present invention, when the input shaft is rotated around the axis by the transmitted power, the internal gear behaves as if it eccentrically rotates around the axis along with the rotation of the input shaft. However, the rotation of the internal gear is restrained by the guide member fixed by the fixed plate, which allows the internal gear to be guided so as to eccentric swing around the axis from the eccentric rotation around the axis. The behavior of the internal gear can be controlled. As a result, the internal gear can be eccentrically swung with respect to the external gear so that the internal teeth sequentially get over the external teeth in the circumferential direction while inscribed the plurality of external teeth with respect to the plurality of internal teeth. Therefore, every time the internal tooth gets over the external tooth due to the eccentric swing of the internal gear, the external tooth can be pressed in the circumferential direction through the internal tooth, and the external gear and the output shaft are rotated around the axis. Can be done.

In this way, the power transmitted to the input shaft is transmitted to the internal gear to eccentrically swing the internal gear, and thereby the external tooth is pressed in the circumferential direction via the internal tooth to transmit the power to the external gear. Can be done. As a result, the external gear and the output shaft can be rotated around the axis. In particular, since the number of external teeth and the number of internal teeth are different, it is possible to decelerate or accelerate the external gear by the difference in the number of teeth. As a result, the output shaft can be rotated while decelerating or increasing the speed with respect to the rotation of the input shaft.

Further, unlike a conventional speed reducer or the like, the internal gear side is eccentrically swung, so that the external gear can be simply rotated around the axis. Therefore, for example, it is not necessary to take out only the rotation component of the external gear, and the power can be directly transmitted from the external gear to the output shaft to rotate the output shaft around the axis. Therefore, it is possible to obtain a simple structure in which the number of parts is suppressed, and it is possible to reduce the size and thickness of the entire transmission device. In addition to that, it can lead to cost reduction and improvement of maintainability.

(2) The internal gear is provided with the internal teeth and is arranged so as to face the fixed plate and the gear body that surrounds the external gear from the outside in the radial direction, and the gear body is located on the outer peripheral edge side. The internal gear plate formed and the accommodating recess formed in the internal gear plate so as to open at least toward the fixed plate side are provided, and the guide member is arranged in the accommodating recess and described as described above. A guide portion that can be inscribed with respect to the inner wall surface of the accommodating recess is provided, and the guide portion is eccentric with respect to the center line of the accommodating recess by the amount of eccentricity between the axis and the eccentric axis. It may be arranged in the accommodating recess.

In this case, the guide portion arranged in the accommodating recess is eccentric with respect to the center line of the accommodating recess by the amount of eccentricity between the axis and the eccentric axis. Therefore, even if the internal gear behaves as if it rotates eccentrically with the rotation of the input shaft, the inner wall surface of the accommodating recess and the guide portion come into contact with each other, so that the rotation of the internal gear can be appropriately restrained. .. In addition, the internal gear can be eccentrically swung while the guide portion is inscribed with respect to the inner wall surface of the accommodating recess. Therefore, the internal gear can be eccentrically swung as if it rotates eccentrically around the guide portion while guiding the movement of the internal gear using the guide portion.
In this way, since the eccentric swing can be performed while guiding the movement of the internal gear by using the guide portion, the eccentric swing can be performed in a stable state with less rattling of the internal gear, and the eccentric swing can be performed from the input shaft. Power can be efficiently transmitted to the output shaft.

(3) The guide portion surrounds the shaft portion fixed to the fixing plate, the guide inner ring portion arranged so as to surround the shaft portion from the outside in the radial direction, and the guide inner ring portion from the outside in the radial direction. A guide outer ring portion arranged in such a manner and a plurality of guide ball portions rotatably held between the guide inner ring portion and the guide outer ring portion are provided, and the guide outer ring portion is formed of the accommodating recess. It may be inscribed on the inner wall surface.

In this case, the guide portion itself can function as a ball bearing, and the guide outer ring portion can be inscribed on the inner wall surface of the accommodating recess. Therefore, the guide outer ring portion can be inscribed in the inner wall surface of the accommodating recess while rotating around the shaft portion according to the movement of the internal gear. Therefore, instead of sliding the inner wall surface of the accommodating recess with respect to the guide outer ring portion, the guide outer ring portion can be smoothly moved by using the rotation (rolling). As a result, the frictional resistance between the guide portion and the accommodating recess can be reduced, and the power loss can be reduced. Therefore, the power transmission efficiency can be improved, and the power can be efficiently transmitted from the input shaft to the output shaft without waste.

(4) The internal tooth may have a circular outer shape in a plan view seen from the eccentric axis direction and may have a rotating body that can rotate.

In this case, since the internal teeth have a rotating body that can rotate, the internal gear is moved with respect to the external gear so that the rolling body sequentially rides over the external teeth in the circumferential direction while rotating the rolling body. It can be eccentrically swung. Therefore, the frictional resistance between the internal gear and the external gear can be reduced, and the power loss can be reduced. Therefore, the power transmission efficiency can be improved, and the power can be efficiently transmitted from the input shaft to the output shaft without waste.

(5) The rolling element may be a ball.

In this case, since the rolling element is a ball, the ball and the external teeth can be brought into point contact with each other, and the frictional resistance between the internal gear and the external gear can be further effectively reduced. Therefore, the power transmission efficiency can be further improved.

(6) The external teeth may be formed in a tooth profile along a trochoidal curve.

In this case, since the external teeth have a so-called trochoidal tooth profile, when the internal gear eccentric swings, the external teeth and the internal teeth can be kept in constant contact with each other, and the external gear can be kept in contact with the internal gear from the internal gear side. It is easy to efficiently transmit power to the side.

(7) An input inner ring portion that is integrally combined with the input shaft and is arranged around the eccentric axis, and an input outer ring that is arranged so as to surround the input inner ring portion from the outside in the radial direction. A portion and a plurality of input balls rotatably held between the input inner ring portion and the input outer ring portion are provided, and the inner gear is integrated with the input outer ring portion. May be combined.

In this case, the input shaft and the internal gear can be combined via the ball bearing composed of the input inner ring portion, the input outer ring portion, and the input ball, so that the assembling property can be improved. , The internal gear can be smoothly eccentrically swung with the rotation of the input shaft.

(8) The output shaft may be integrally formed with the external gear.

In this case, since the output shaft and the external gear can be integrated, it is easy to further reduce the size and thickness of the transmission device.

According to the present invention, it is possible to provide a transmission device that can be easily miniaturized and thinned, and can lead to cost reduction and improvement of maintainability.

It is an external perspective view which shows the embodiment of the speed reducer (transmission device) which concerns on this invention. It is a vertical sectional view of the speed reducer along the line AA shown in FIG. It is a perspective view which shows the state which removed the upper fixing plate from the state shown in FIG. It is a perspective view which looked at the input shaft shown in FIG. 2 from the upper end side. It is a perspective view which looked at the internal gear shown in FIG. 3 from the upper side. It is a top view of the internal gear shown in FIG. FIG. 5 is a perspective view of the internal gear shown in FIG. 5 as viewed from below. It is a perspective view which shows the state which removed the ring plate from the state shown in FIG. It is a top view which shows the state which removed the ring plate from the state shown in FIG. It is a perspective view of the guide member shown in FIG. It is a vertical sectional view of the guide member along the line BB shown in FIG. It is a top view which shows the operating state of the eccentric swing of the internal gear shown in FIG. FIG. 5 is a plan view showing an operating state in which the internal gear swings eccentrically in the counterclockwise direction from the state shown in FIG. FIG. 3 is a plan view showing an operating state in which the internal gear further eccentrically swings counterclockwise from the state shown in FIG. FIG. 3 is a plan view showing an operating state in which the internal gear further eccentrically swings counterclockwise from the state shown in FIG. It is a figure which shows the relationship between the internal tooth and the external tooth at the time of eccentric swing of an internal gear. It is a figure which shows the deformation example of the external tooth in the external gear.

Hereinafter, embodiments of the transmission device according to the present invention will be described with reference to the drawings. In the present embodiment, a case where the transmission device is applied to a speed reducer having a reduction ratio of 1/16 will be described as an example.

As shown in FIGS. 1 and 2, the speed reducer (transmission device according to the present invention) 1 of the present embodiment includes an input shaft 2, an internal gear 4 having a plurality of internal teeth 3, and a plurality of external teeth 5. It mainly includes an external gear 6, an output shaft 7, and a casing 8.

The input shaft 2 and the output shaft 7 are arranged so that their central axes are located on a common common axis. In the present embodiment, this common axis is referred to as a rotation axis (axis according to the present invention) O1, and the direction intersecting the rotation axis O1 in a plan view from the direction of the rotation axis O1 is referred to as a radial direction, and is around the rotation axis O1. The direction of rotation is called the circumferential direction. Further, the direction along the rotation axis O1 is called the vertical direction. Of the vertical directions, the direction from the input shaft 2 to the output shaft 7 is referred to as upward, and the opposite direction is referred to as downward.

(casing)
First, the casing 8 will be described.
The casing 8 includes an upper fixing plate 10 and a lower fixing plate (fixing plate according to the present invention) 11 that are integrally combined with each other in a state of being arranged so as to face each other with a predetermined distance in the vertical direction.

The upper fixing plate 10 is formed in a square shape in a plan view having a constant thickness. However, the outer shape of the upper fixing plate 10 is not limited to a square shape in a plan view, and may be, for example, a circular shape in a plan view, an ellipse shape, a polygonal shape, or the like.
A through hole 15 is formed in the central portion of the upper fixing plate 10 so as to penetrate the upper fixing plate 10 in the vertical direction. The through hole 15 is arranged coaxially with the rotation axis O1 and is formed in a circular shape in a plan view.

Of the four corners (four corners) of the upper fixing plate 10, a pair of corners arranged diagonally across the rotation axis O1 have connecting holes (not shown) penetrating the upper fixing plate 10 in the vertical direction. It is formed. Further, of the four corners (four corners) of the upper fixing plate 10, the remaining pair of corners are formed with positioning holes 16 that penetrate the upper fixing plate 10 in the vertical direction.

Further, the upper fixing plate 10 is formed with a plurality of support holes 17 arranged at equal intervals in the circumferential direction about the rotation axis O1.
The support hole 17 is formed so as to penetrate the upper fixing plate 10 in the vertical direction and is formed in a circular shape in a plan view. In the illustrated example, four support holes 17 are formed with an interval of 90 degrees about the rotation axis O1. However, the number of support holes 17 is not limited to this case.

The lower fixing plate 11 has the same configuration as the upper fixing plate 10 described above. Therefore, the lower fixing plate 11 is designated by the same reference numerals with respect to the same components as the upper fixing plate 10, and detailed description thereof will be omitted.
By forming the upper fixing plate 10 and the lower fixing plate 11 in the same configuration in this way, one fixing plate can be used as both the upper fixing plate 10 and the lower fixing plate 11, so that the configuration can be simplified. can.

However, the upper fixing plate 10 and the lower fixing plate 11 do not have to have the same configuration, and for example, the upper fixing plate 10 and the lower fixing plate 11 may have different outer shapes, outer sizes, different thicknesses, and the like.
In particular, the four support holes 17 need only be formed on the lower fixing plate 11 and need not be formed on the upper fixing plate 10.

As shown in FIGS. 1 to 3, a pair of first spacers 18 and a pair of second spacers 19 are arranged between the upper fixing plate 10 and the lower fixing plate 11 configured as described above. ..
The first spacer 18 is formed in a columnar shape having a predetermined length in the vertical direction, and is arranged between the communication hole in the upper fixing plate 10 and the communication hole in the lower fixing plate 11. The first spacer 18 has screw holes 18a formed on the upper end surface and the lower end surface (see FIG. 3).

The second spacer 19 is formed in a columnar shape having the same length as the first spacer 18 in the vertical direction, and is arranged between the positioning hole 16 in the upper fixing plate 10 and the positioning hole 16 in the lower fixing plate 11. There is. An upper positioning pin 19a is formed on the upper end surface of the second spacer 19 so as to project upward and to be inserted into the positioning hole 16 in the upper fixing plate 10. A lower positioning pin (not shown) is formed on the lower end surface of the second spacer 19 so as to project downward and to be inserted into the positioning hole 16 in the lower fixing plate 11.

As a result, as shown in FIGS. 1 and 2, the upper fixing plate 10 and the lower fixing plate 11 are first spaced apart by the lengths of the first spacer 18 and the second spacer 19 in the vertical direction. It is combined via the spacer 18 and the second spacer 19.
Then, a pair of connecting screws 20 are screwed into the screw holes 18a of the first spacer 18 from above through the communication holes of the upper fixing plate 10, and the pair of connecting screws 20 of the first spacer 18 are screwed through the communication holes of the lower fixing plate 11. It is screwed into the screw hole 18a from below. As a result, the upper fixing plate 10 and the lower fixing plate 11 are integrally combined via the first spacer 18 and the second spacer 19.

The internal gear 4 and the external gear 6 are arranged inside the casing 8 configured as described above, that is, between the upper fixing plate 10 and the lower fixing plate 11.
The casing 8 of the present embodiment has a configuration in which the periphery of the internal gear 4 and the external gear 6 is open, but the present invention is not limited to this case. For example, the internal gear 4 and the external gear 6 are radially outside. A side wall panel or the like surrounding the structure may be attached between the upper fixing plate 10 and the lower fixing plate 11.

(Input axis)
As shown in FIG. 2, the input shaft 2 is arranged along the vertical direction and is rotatably arranged around the rotation axis O1 by the power (torque) transmitted from the outside. In the illustrated example, the input shaft 2 is formed in a hollow cylindrical shape, but the present invention is not limited to this case, and the input shaft 2 may be formed in a solid shape.

The input shaft 2 is arranged so that the upper end portion enters the through hole 15 from below the lower fixing plate 11. At this time, the upper end portion of the input shaft 2 is not in contact with the through hole 15. Further, as shown in FIGS. 2 and 4, a fitting hole 2a that is recessed downward is formed on the upper end surface of the input shaft 2. The fitting hole 2a is formed in a circular shape in a plan view centering on the eccentric axis O2 eccentric in the radial direction from the rotation axis O1.

The direction that intersects the eccentric axis O2 in a plan view from the eccentric axis O2 direction is referred to as a radial direction, and the direction that orbits around the eccentric axis O2 is referred to as a circumferential direction. In particular, in the description of the constituent members arranged around the eccentric axis O2, the eccentric axis O2 is used as a reference when simply referring to "diameter direction and circumferential direction".

(Internal gear)
As shown in FIGS. 1 and 2, the internal gear 4 is arranged between the upper fixing plate 10 and the lower fixing plate 11 as described above. Specifically, the internal gear 4 is arranged closer to the lower fixing plate 11 than the external gear 6. As a result, the external gear 6 is arranged on the upper side with respect to the internal gear 4 (that is, one side in the rotation axis O1 direction), and the lower fixed plate 11 is arranged on the lower side with respect to the internal gear 4 (that is, the other side in the rotation axis O1 direction). It is located on the side).

As shown in FIGS. 2, 5 and 7, the internal gear 4 is arranged around the eccentric axis O2, operates with the rotation of the input shaft 2, and orbits around the eccentric axis O2. It has a plurality of internal teeth 3 arranged at intervals in the direction.
This will be described in detail below.

The internal gear 4 is arranged so as to face the lower fixed plate 11 in the vertical direction, and the internal gear plate 30 having an external shape formed into a circular shape in a plan view and the outer peripheral edge portion of the internal gear plate 30 thereof. An annular gear wall portion (gear body according to the present invention) 31 that protrudes upward over the entire circumference is provided.

The internal gear plate 30 has an outer diameter size so as to fit inside the first spacer 18 and the second spacer 19 and to secure a predetermined gap between the first spacer 18 and the second spacer 19. Is stipulated.
The internal gear plate 30 is formed to have a sufficient thickness so as to have appropriate rigidity (mechanical strength). In the illustrated example, the internal gear plate 30 is formed to be slightly thicker than the thickness of the upper fixing plate 10 and the lower fixing plate 11.

At the central portion of the internal gear plate 30, a fitting recess 32 (see FIG. 2) recessed downward from the upper surface is formed coaxially with the eccentric axis O2. The fitting recess 32 is formed in a circular shape in a plan view, and is formed, for example, with an inner diameter larger than the diameter of the input shaft 2.

Further, the internal gear plate 30 is formed with a housing recess 33 that penetrates the internal gear plate 30 in the vertical direction. The accommodating recess 33 does not have to penetrate the internal gear plate 30 in the vertical direction, and may be opened at least toward the lower fixing plate 11.
The accommodating recesses 33 are formed in a circular shape in a plan view having a predetermined inner diameter, and a plurality of accommodating recesses 33 are formed at equal intervals in the circumferential direction about the eccentric axis O2. In the illustrated example, four accommodating recesses 33 are formed with an interval of 90 degrees about the eccentric axis O2.

In particular, the accommodating recess 33 is formed so as to be arranged above each of the four support holes 17 formed in the lower fixing plate 11. Specifically, the accommodating recess 33 is formed so that each support hole 17 is located inside each accommodating recess 33 in a plan view of the internal gear plate 30. The number of accommodating recesses 33 is not limited to four, and may be one or a plurality other than four as long as it corresponds to the number of support holes 17.

Further, the internal gear plate 30 is formed with a plurality of lightening recesses 35 that are recessed downward in portions other than the fitting recess 32 and the housing recess 33 described above.
The lightening recess 35 is not essential and may not be formed, but when the internal gear plate 30 has a sufficient thickness, it is preferably formed from the viewpoint of weight reduction. Further, the shape and number of the lightening recesses 35 may be appropriately changed, or may be formed so as to penetrate the internal gear plate 30 in the vertical direction.

The gear wall portion 31 is formed so as to project upward from the upper surface of the internal gear plate 30 along the outer peripheral edge portion of the internal gear plate 30. As a result, the gear wall portion 31 surrounds the external gear 6 from the outside in the radial direction.

On the outer peripheral surface side of the gear wall portion 31, a bulging portion 36 that bulges outward in the radial direction is formed. The bulging portion 36 extends in the vertical direction with a length extending from the upper end surface of the gear wall portion 31 to the lower surface of the internal gear plate 30, and is semicircular toward the outside in the radial direction in the plan view of the internal gear plate 30. It is formed so as to swell. A screw hole 36a opened upward is formed in the bulging portion 36.
A plurality of the bulging portions 36 configured in this way are formed at equal intervals in the circumferential direction about the eccentric axis O2. Specifically, four bulging portions 36 are formed. However, the number of bulging portions 36 is not limited to four, and may be changed as appropriate.

On the inner peripheral surface side of the gear wall portion 31, a plurality of internal teeth 3 arranged at equal intervals in the circumferential direction around the eccentric axis O2 are formed over the entire circumference of the gear wall portion 31. ing.
The internal tooth 3 has a circular outer shape in a plan view of the internal gear plate 30, and has a ball 37 as a rotating body that can rotate.
Further, the internal teeth 3 are located on both sides of the ball accommodating portion 38 formed so as to be recessed from the inner peripheral surface of the gear wall portion 31 in the radial direction and the ball accommodating portion 38 in the circumferential direction, and the gears. It includes a holding claw 39 that projects from the inside of the wall portion 31 toward the inside in the radial direction and holds the ball 37 so as to be rollable.

The ball 37 is housed in the ball accommodating portion 38 in a state of being placed on the upper surface of the internal gear plate 30, and is rotatably held by the holding claw 39 without protruding inward in the radial direction. The ball 37 protrudes inward in the radial direction from the holding claw 39, and is capable of contacting and engaging with the external teeth 5 of the external gear 6.
The outer line connecting the outer peripheral surface of the ball 37 and the outer peripheral surface of the holding claw 39 that holds the ball 37 from both sides in the circumferential direction has a smooth tooth shape protruding inward in the radial direction. ..

The internal teeth 3 having the balls 37 configured as described above are formed so that the number of teeth is 17 (that is, the number of balls 37 is 17). Therefore, the internal teeth 3 are arranged at an angle of approximately 21 degrees about the eccentric axis O2.

Further, as shown in FIGS. 2 and 3, a ring plate 40 is superposed on the gear wall portion 31 from above.
The ring plate 40 is arranged coaxially with the eccentric axis O2 and is formed in a ring shape having the same diameter as the outer diameter of the gear wall portion 31. Further, the ring plate 40 is formed with a flange portion that projects outward from the outer peripheral edge portion in the radial direction and that overlaps with the bulging portion 36 of the internal gear 4. Then, the ring plate 40 is integrally combined with the gear wall portion 31 so as to cover the ball 37 from above by the connecting screw 41 screwed into the screw hole 36a of the bulging portion 36 via the collar portion. ing. As a result, each ball 37 is restricted from coming out of the ball accommodating portion 38 upward by the ring plate 40.

The internal gear 4 configured as described above is integrally formed by, for example, cutting a metal material, die cutting, injection molding of a synthetic resin material, or the like, except for the ball 37.

(Central bearing)
As shown in FIG. 2, the internal gear 4 configured as described above is combined with the input shaft 2 via the central bearing 50.
The central bearing 50 is integrally combined with the upper end portion of the input shaft 2, and the input inner ring portion 51 arranged around the eccentric axis O2 and the input outer ring portion 51 surrounding the input inner ring portion 51 from the outside in the radial direction. 52 is provided with a plurality of input balls 53 rotatably held between the input inner ring portion 51 and the input outer ring portion 52.

The input inner ring portion 51 includes a first inner ring portion 55 that is combined with the upper end portion of the input shaft 2, and a second inner ring portion 56 that overlaps the first inner ring portion 55 from above.
The first inner ring portion 55 includes a fitting shaft portion 57 that is tightly fitted inside a fitting hole 2a formed on the upper end surface of the input shaft 2, and a fitting shaft portion 57 that is radially outside from the upper end portion of the fitting shaft portion 57. It includes an annular flange portion 58 formed so as to extend toward.

The fitting shaft portion 57 is arranged coaxially with the eccentric axis O2 and slightly protrudes above the fitting hole 2a. Further, the upper end surface of the fitting shaft portion 57 is a flat surface. A screw hole 57a opened upward is formed in the fitting shaft portion 57 coaxially with the eccentric axis O2.
A first inner rolling surface 58a is formed on the outer peripheral surface of the flange portion 58 over the entire circumference. The first inner rolling surface 58a is formed in a vertical cross-sectional view taper shape that extends inward in the radial direction from the outer peripheral surface of the flange portion 58 upward. As a result, the first inner rolling surface 58a is formed so as to face outward in the radial direction and diagonally upward.

The second inner ring portion 56 is a disk plate that overlaps the upper end surface of the fitting shaft portion 57, and is arranged coaxially with the eccentric axis O2. A second inner rolling surface 56a is formed on the outer peripheral surface of the second inner ring portion 56 over the entire circumference. The second inner rolling surface 56a is formed in a vertical cross-sectional view taper shape that extends inward in the radial direction from the outer peripheral surface of the second inner ring portion 56 downward. As a result, the second inner rolling surface 56a is formed so as to face outward in the radial direction and diagonally downward.

The second inner ring portion 56 configured in this way is combined with the first inner ring portion 55 by a connecting screw 59 screwed into the screw hole 57a. The input inner ring portion 51 composed of the first inner ring portion 55 and the second inner ring portion 56 combined with each other has an input shaft formed by the fitting shaft portion 57 being tightly fitted inside the fitting hole 2a. It is integrally combined with respect to 2.

Further, the first inner rolling surface 58a and the second inner rolling surface 56a provide a V-shaped inner annular groove 60 in a vertical cross-sectional view with an opening angle of approximately 90 degrees on the outer peripheral surface side of the input inner ring portion 51. It is formed so as to be recessed inward in the radial direction.

The input outer ring portion 52 includes a first outer ring portion 65 that surrounds the first inner ring portion 55 from the outside in the radial direction, and a second outer ring portion 66 that surrounds the second inner ring portion 56 from the outside in the radial direction.
The first outer ring portion 65 is formed in a ring shape coaxially with the eccentric axis O2, and is integrally formed so that the outer peripheral edge portion is connected to the inside of the fitting recess 32. However, the present invention is not limited to this case, and the first outer ring portion 65 may be tightly fitted inside the fitting recess 32.
A first outer rolling surface 65a is formed on the inner peripheral surface of the first outer ring portion 65 over the entire circumference. The first outer rolling surface 65a is formed in a vertical cross-sectional view taper shape that extends outward in the radial direction from the inner peripheral surface of the first outer ring portion 65 toward the upper side. As a result, the first outer rolling surface 65a is formed so as to face inward in the radial direction and diagonally upward.

The second outer ring portion 66 is formed in a ring shape coaxially arranged with the eccentric axis O2, and is tightly fitted inside the fitting recess 32.
A second outer rolling surface 66a is formed on the inner peripheral surface of the second outer ring portion 66 over the entire circumference. The second outer rolling surface 66a is formed in a vertical cross-sectional view taper shape extending outward in the radial direction from the inner peripheral surface of the second outer ring portion 66 downward. As a result, the second outer rolling surface 66a is formed so as to face inward in the radial direction and diagonally downward.

The input outer ring portion 52 and the internal gear 4 configured as described above are integrally combined. Further, a V-shaped outer annular groove in a vertical cross-sectional view having an opening angle of approximately 90 degrees on the inner peripheral surface side of the input outer ring portion 52 by the first outer rolling surface 65a and the second outer rolling surface 66a. 61 is formed so as to be recessed outward in the radial direction. Therefore, an annular space is defined between the inner annular groove 60 and the outer annular groove 61 described above.

The input balls 53 are housed in the annular space at intervals in the circumferential direction. In the present embodiment, the plurality of input balls 53 are arranged in the annular space in a state of being positioned in the circumferential direction by the retainer (retainer) 53a.
However, the present invention is not limited to this case, and for example, the input balls 53 may be arranged in the annular space so as to be arranged in the circumferential direction in a state where the input balls 53 are in contact with each other without a gap. That is, a full ball configuration in which the input balls 53 are arranged without gaps over the entire circumference in the annular space may be used.

Further, the plurality of input balls 53 include a first inner rolling surface 58a and a second inner rolling surface 56a formed on the input inner ring portion 51 side, and a first outer rolling surface formed on the input outer ring portion 52 side. It is held so that it can roll in a state of being in contact with the moving surface 65a and the second outer rolling surface 66a (four-point contact state).

Since the input shaft 2 and the internal gear 4 are combined via the central bearing 50 configured as described above, the power transmitted to the input shaft 2 can be transmitted to the internal gear 4 via the central bearing 50. It is possible.

(External gear)
2 As shown in FIGS. 8 and 9, the external gear 6 is arranged closer to the upper fixing plate 10 than the internal gear 4, and is arranged inside the gear wall portion 31 of the internal gear 4.
The external gear 6 is arranged coaxially with the rotation axis O1, is rotatable around the rotation axis O1, and has a plurality of external teeth 5 that are inscribed and meshable with the plurality of internal teeth 3. There is. At the center of the external gear 6, a fitting hole 6a that penetrates the external gear 6 in the vertical direction is formed coaxially with the axis.

The plurality of external teeth 5 are arranged at equal intervals in the circumferential direction with the rotation axis O1 as the center, and are arranged so as to have a number of teeth different from the number of internal teeth 3 (17 teeth). Specifically, the outer teeth 5 are arranged so as to have 16 teeth, which is one less than the internal teeth 3. Therefore, the external teeth 5 are arranged at an angle of approximately 22.5 degrees about the rotation axis O1.
Further, the external tooth 5 of the present embodiment has a tooth profile along a trochoidal curve, that is, a so-called trochoidal tooth profile. As a result, the balls 37 in the plurality of internal teeth 3 and the plurality of external teeth 5 can be in constant contact with each other.

(Output shaft)
As shown in FIGS. 2 and 8, the output shaft 7 is arranged along the vertical direction and is rotatably arranged around the rotation axis O1. In the illustrated example, the output shaft 7 is formed in a hollow cylindrical shape, but the present invention is not limited to this case, and the output shaft 7 may be formed in a solid shape.

The output shaft 7 is arranged so as to enter the through hole 15 from above the upper fixing plate 10. At this time, the output shaft 7 is not in contact with the through hole 15. The lower end of the output shaft 7 is tightly fitted inside the fitting hole 6a formed in the external gear 6. As a result, the output shaft 7 is integrally combined with the external gear 6, and can rotate around the rotation axis O1 as the external gear 6 rotates.

(Guide member)
In the speed reducer 1 configured as described above, the movement (behavior) of the internal gear 4 is controlled by the guide member 70 as shown in FIGS. 2, 5 to 7. The guide member 70 is fixed to the lower fixing plate 11 and plays a role of restraining the rotation of the internal gear 4 and guiding the internal gear 4 so as to eccentrically swing around the rotation axis O1 by the restraint.
This will be described in detail below.

The guide member 70 is provided according to the number of the support holes 17 formed in the lower fixing plate 11 and the accommodating recesses 33 formed in the internal gear 4. Therefore, in this embodiment, four guide members 70 are provided. Since all of the four guide members 70 have the same configuration, one guide member 70 will be described in detail, and the remaining guide members 70 will have the same reference numerals to the common constituent members. The explanation is omitted.

The guide member 70 includes a guide portion 71 held by a support hole 17 so as to stand up from the lower fixing plate 11 upward. The guide portion 71 is accommodated in the accommodating recess 33 by entering the accommodating recess 33 in the internal gear 4 from below, and can be inscribed with respect to the inner wall surface of the accommodating recess 33.
Therefore, the four guide portions 71 are arranged at 90-degree angles about the rotation axis O1 and are accommodated in the four accommodating recesses 33, respectively.

In particular, as shown in FIG. 6, the guide portion 71 is arranged in the accommodating recess 33 so as to be eccentric with respect to the center line O3 of the accommodating recess 33 by the amount of eccentricity H between the rotation axis O1 and the eccentric axis O2. Has been done. Further, the direction in which the eccentric axis O2 is eccentric with respect to the rotation axis O1 and the direction in which the center line O4 of the guide portion 71 is eccentric with respect to the center line O3 of the accommodating recess 33 are in the same direction. The guide portion 71 is held by the lower fixing plate 11.

As shown in FIGS. 2, 10 and 11, the guide portion 71 is a guide fixed to the shaft portion 72 held in the support hole 17 and the shaft portion 72 so as to surround the shaft portion 72 from the outside in the radial direction. An inner ring portion 73, a guide outer ring portion 74 that surrounds the guide inner ring portion 73 from the outside in the radial direction, and a plurality of guide balls 75 that are rotatably arranged between the guide inner ring portion 73 and the guide outer ring portion 74. I have.

The lower end of the shaft portion 72 is tightly fitted inside the support hole 17. As a result, the entire guide member 70 is fixed to the lower fixing plate 11. The shaft portion 72 may be fitted inside the support hole 17 so as to rotate. The upper end portion of the shaft portion 72 enters the accommodating recess 33 from below.

The guide inner ring portion 73 is fixed to the upper end portion of the shaft portion 72. An inner rolling surface 73a on which the guide ball 75 rolls is formed on the outer peripheral surface of the guide inner ring portion 73.

The guide outer ring portion 74 further surrounds the first guide outer ring portion 76 that surrounds the guide inner ring portion 73 from the outside in the radial direction and the first guide outer ring portion 76 from the outer side in the radial direction, and with respect to the first guide outer ring portion 76. It includes a second guide outer ring portion 77 that is integrally combined. An outer rolling surface 76a on which the guide ball 75 rolls is formed on the inner peripheral surface of the first guide outer ring portion 76.

The guide balls 75 are housed in an annular space formed between the guide inner ring portion 73 and the first guide outer ring portion 76 at intervals in the circumferential direction, and the inner rolling surface 73a and the outer rolling surface 73a. It is in contact with 76a. The plurality of guide balls 75 are arranged in the annular space in a state of being positioned in the circumferential direction by a retainer (retainer) (not shown).
However, the present invention is not limited to this case, and for example, the guide balls 75 may be arranged in the annular space so as to be arranged in the circumferential direction in a state where the guide balls 75 are in contact with each other without a gap. That is, a full ball configuration in which the guide balls 75 are arranged without gaps over the entire circumference in the annular space may be used.

Further, on the outer peripheral surface side of the second guide outer ring portion 77, a plurality of ball holding holes 77a recessed inward in the radial direction are formed at equal intervals over the entire circumference. In these plurality of ball holding holes 77a, contact balls 78 that can come into contact with the inner wall surface of the accommodating recess 33 are rotatably held.
The guide outer ring portion 74 is integrally combined with a regulation ring 79 that regulates the contact ball 78 from coming out upward from the ball holding hole 77a.

The guide member 70 configured as described above can be inscribed with respect to the inner wall surface of the accommodating recess 33 via the contact ball 78.
As a result, the rotation of the internal gear 4 can be restrained by using the four guide members 70 fixed to the lower fixing plate 11, and the internal gear 4 is eccentrically swung around the rotation axis O1. It is possible to guide and control the movement.

(Action of reducer)
Next, a case where the speed reducer 1 configured as described above is operated will be described.
In this case, for example, when power from an external drive source (for example, a stepping motor or the like) is transmitted to the input shaft 2 shown in FIG. 2, the input shaft 2 rotates around the rotation axis O1. As a result, the rotational force transmitted to the input shaft 2 can be transmitted to the internal gear 4 via the central bearing 50 (input inner ring portion 51, input ball 53, and input outer ring portion 52). Therefore, the internal gear 4 exhibits an eccentric rotation around the rotation axis O1 in the counterclockwise direction as shown by the arrow K1 shown in FIG. 12, for example, as the input shaft 2 rotates.

However, the rotation of the internal gear 4 is restrained by the guide member 70 fixed by the lower fixing plate 11, so that the eccentric rotation around the rotation axis O1 becomes eccentric swing around the rotation axis O1. The operation is controlled.

Specifically, the guide portion 71 arranged in the accommodating recess 33 is eccentric with respect to the center line O3 of the accommodating recess 33 by the amount of eccentricity H between the rotation axis O1 and the eccentric axis O2 (FIG. 6). Therefore, even if the internal gear 4 behaves as if it rotates eccentrically around the rotation axis O1 as the input shaft 2 rotates, the inner wall surface of the accommodating recess 33 and the guide portion 71 are inscribed with each other, so that the internal gear 4 It is possible to properly restrain the rotation of. In addition, the internal gear 4 can be eccentrically swung while the guide portion 71 is inscribed in the inner wall surface of the accommodating recess 33. Therefore, while guiding the movement of the internal gear 4 using the guide portion 71, the internal gear 4 is eccentrically swung in the counterclockwise direction as if it were eccentrically rotated around the guide portion 71, as shown by the arrow K2. be able to.

As a result, as shown in FIG. 12, while the plurality of external teeth 5 are inscribed with respect to the plurality of internal teeth 3, the internal teeth 3 sequentially overcome the external teeth 5 in the circumferential direction with respect to the external gear 6. The internal gear 4 can be eccentrically swung.
More specifically, when the inner wall surface of the accommodating recess 33 and the guide portion 71 are inscribed in the first inscribed region P1, the internal gear 4 swings eccentrically around the rotation axis O1 in the counterclockwise direction. As shown in FIG. 13, the inner wall surface of the accommodating recess 33 and the guide portion 71 are inscribed in the second inscribed region P2. The second inscribed region P2 is located on the counterclockwise side of the first inscribed region P1 along the inner wall surface of the accommodating recess 33.

Next, when the internal gear 4 further eccentrically swings in the counterclockwise direction, as shown in FIG. 14, the inner wall surface of the accommodating recess 33 and the guide portion 71 are inscribed in the third inscribed region P3. The third inscribed region P3 is located on the counterclockwise side of the second inscribed region P2 along the inner wall surface of the accommodating recess 33.
Next, when the internal gear 4 further eccentrically swings in the counterclockwise direction, as shown in FIG. 15, the inner wall surface of the accommodating recess 33 and the guide portion 71 are inscribed in the fourth inscribed region P4. The fourth inscribed region P4 is located on the counterclockwise side of the first inscribed region P1 along the inner wall surface of the accommodating recess 33.

In this way, the internal gear 4 performs eccentric swing so as to sequentially repeat the states shown in FIGS. 12 to 15. Then, each time the internal tooth 3 gets over the external tooth 5 due to the eccentric swing of the internal gear 4, the external tooth 5 can be pressed in the circumferential direction via the internal tooth 3 as shown by an arrow F shown in FIG. The external gear 6 can be rotated about the rotation axis O1 in the clockwise direction (arrow K2 direction) opposite to that of the internal gear 4. The arrow F is directed from the center point of the ball 37 constituting the internal tooth 3 toward the contact point between the ball 37 and the external tooth 5.

As described above, the power transmitted to the input shaft 2 is transmitted to the internal gear 4 to eccentrically swing the internal gear 4, whereby the external teeth 5 are pressed in the circumferential direction via the internal teeth 3 to be external. Power can be transmitted to the gear 6. As a result, as shown in FIG. 12, the external gear 6 and the output shaft 7 can be rotated clockwise around the rotation axis O1.
In particular, since the number of teeth of the external tooth 5 (16 teeth) and the number of teeth of the internal tooth 3 (16 teeth, that is, 16 balls 37) are different, the external gear 6 is decelerated (decelerated) by the angle difference of the number of teeth. It is possible to make a ratio of 1/16). As a result, the output shaft 7 can be rotated while being decelerated with respect to the rotation of the input shaft 2.

In particular, unlike the conventional speed reducer or the like, the speed reducer 1 of the present embodiment eccentrically swings the internal gear 4 side. Therefore, the external gear 6 should be a simple rotation operation that rotates around the rotation axis O1. Can be done. Therefore, for example, it is not necessary to take out only the rotation component of the external gear 6, and the power can be directly transmitted from the external gear 6 to the output shaft 7 to rotate the output shaft 7 around the rotation axis O1.
Therefore, it is possible to make a simple structure in which the number of parts is suppressed, and it is possible to reduce the size and thickness of the entire speed reducer 1. In addition to that, it can lead to cost reduction and improvement of maintainability.

As described above, according to the speed reducer 1 of the present embodiment, it is easy to reduce the size and thickness, and it is possible to reduce the cost and improve the maintainability.
In particular, since the speed reducer 1 can be easily made smaller and thinner, it can be suitably used for small parts in various fields. For example, the speed reducer 1 is used for various devices (for example, industrial robots, robot arms, robot hands, medical support devices that support patient movements, home appliances, AV devices, etc.) that move small movable parts. It can be preferably used.

Further, according to the speed reducer 1 of the present embodiment, the guide portion 71 can be used to guide the movement of the internal gear 4 while swinging eccentrically, so that the internal gear 4 is stable with little rattling. The eccentric swing can be performed, and the power can be efficiently transmitted from the input shaft 2 to the output shaft 7.

In particular, the guide portion 71 itself can function as a ball bearing, and the guide outer ring portion 74 can be inscribed on the inner wall surface of the accommodating recess 33. Therefore, the guide outer ring portion 74 can be brought into contact with the inner wall surface of the accommodating recess 33 while rotating around the shaft portion 72 according to the movement of the internal gear 4. Therefore, instead of sliding the inner wall surface of the accommodating recess 33 with respect to the guide outer ring portion 74, the guide outer ring portion 74 can be smoothly moved by using the rotation (rolling). As a result, the frictional resistance between the guide portion 71 and the accommodating recess 33 can be reduced, and the power loss can be reduced. Therefore, the power transmission efficiency can be improved, and the power can be efficiently transmitted from the input shaft 2 to the output shaft 7 without waste.

In addition, in the present embodiment, the contact ball 78 is further rotatably held by the guide outer ring portion 74, and can be inscribed on the inner wall surface of the accommodating recess 33 via the contact ball 78. Therefore, the above-mentioned action and effect can be more effectively achieved.

Further, since the internal tooth 3 has the ball 37, the internal gear 4 is changed to the external gear so that the ball 37 sequentially rides over the external tooth 5 in the circumferential direction while rotating the ball 37 as shown in FIG. It can be eccentrically swung with respect to 6. Therefore, the frictional resistance between the internal gear 4 and the external gear 6 can be reduced, and the power loss can be reduced. Therefore, the power transmission efficiency can be improved, and the power can be efficiently transmitted from the input shaft 2 to the output shaft 7 without waste.
In particular, since the balls 37 and the external teeth 5 can be brought into point contact with each other, the frictional resistance between the internal gear 4 and the external gear 6 can be effectively reduced.

Further, since the external tooth 5 has a so-called trochoidal tooth profile, it is possible to maintain a state in which the external tooth 5 and the internal tooth 3 are in constant contact with each other when the internal gear 4 swings eccentrically, and the internal gear 4 can be viewed from the side. It is easy to efficiently transmit power to the external gear 6 side.

Further, since the input shaft 2 and the internal gear 4 can be combined via the central bearing 50 composed of the input inner ring portion 51, the input outer ring portion 52, and the input ball 53, the assembling property is improved. At the same time, the internal gear 4 can be smoothly eccentrically swung with the rotation of the input shaft 2.

Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiments and modifications thereof include, for example, those that can be easily assumed by those skilled in the art, those that are substantially the same, those that have an equal range, and the like.

For example, in the above embodiment, the case where the reduction ratio is set to 1/16 has been described as an example, but the present invention is not limited to this case, and the reduction ratio may be changed as appropriate. In this case, the relationship between the number of internal teeth 3 and the number of external teeth 5 may be appropriately changed according to the reduction ratio.

Further, in the above embodiment, a part of the internal teeth 3 is a ball 37, but the ball 37 is not limited to the ball 37, and for example, a columnar pin may be used as a rolling element. Further, the internal teeth 3 may be configured to have, for example, a trochoidal tooth profile without using a rolling element. Even in these cases, the same effects as those in the above embodiment can be achieved.

Further, in the above embodiment, a ball bearing structure including a guide inner ring portion 73, a guide outer ring portion 74, and a guide ball 75 is adopted as the guide portion 71 constituting the guide member 70, but the present invention is not limited to this case.
For example, the guide portion 71 may be formed of a slide bearing in which the outer ring portion is slidably supported around the shaft portion 72, and the outer ring portion may be inscribed with respect to the inner wall surface of the accommodating recess 33. Even in this case, the same effect can be achieved. In particular, it is effective when the size of the accommodating recess 33 is reduced. Therefore, it is effective when further downsizing the internal gear 4.
Further, the guide portion 71 itself may be a columnar pin or the like. Even in this case, since the outer peripheral surface of the pin can be inscribed with respect to the inner wall surface of the accommodating recess 33, the same effect can be achieved. In particular, it is effective when the internal gear 4 is to be further miniaturized.

Further, in the above embodiment, the first inner ring portion 55 of the central bearing 50 and the input shaft 2 may be integrally formed, or the output shaft 7 and the external gear 6 may be integrally formed. In these cases, it is easy to further reduce the size and thickness of the speed reducer 1.
Furthermore, the central bearing 50 is not essential and may not be provided. In this case, the internal gear 4 may be directly combined with the input shaft 2 in a state of being eccentric with respect to the input shaft 2.

Further, in the above embodiment, as shown in FIG. 16, when the ball 37 constituting the internal tooth 3 presses the external tooth 5 in the circumferential direction with the eccentric swing of the internal gear 4, one of the external teeth 5 is a tooth. When the ball 37 is in contact with the region excluding the tip 5a side and the tooth bottom 5b side, the external tooth 5 can be efficiently pressed in the circumferential direction, which greatly contributes to power transmission.
On the contrary, when the ball 37 is in contact with the tooth tip 5a side and the tooth bottom 5b side of the external tooth 5, it is difficult to efficiently press the external tooth 5 in the circumferential direction, which greatly contributes to power transmission. do not. In addition to that, when the phase of the internal gear 4 and the external gear 6 is deviated due to a combination error of the external gear 6 and the internal gear 4, for example, the tooth tip 5a side and the tooth bottom 5b side of the external tooth 5 are the balls 37. It may affect the movement of.

Therefore, as shown in FIG. 17, the tooth tip 5a side and the tooth bottom 5b side of the external tooth 5 (that is, the tooth groove portion located between the external teeth 5 adjacent to each other in the circumferential direction) are shaved by cutting or the like. A notched curved surface 5c may be formed. As a result, the ball 37 can be smoothly moved without disturbing the power transmission from the internal teeth 3 to the external teeth 5 and without being affected by the combination error of the external gear 6 and the internal gear 4.

O1 ... Rotation axis (axis)
O2 ... Eccentric axis 1 ... Reducer (transmission device)
2 ... Input shaft 3 ... Internal tooth 4 ... Internal gear 5 ... External tooth 6 ... External gear 7 ... Output shaft 11 ... Lower fixed plate (fixed plate)
30 ... Internal gear plate 31 ... Gear wall (gear body)
33 ... Containment recess 37 ... Ball 51 ... Input inner ring 52 ... Input outer ring 53 ... Input ball 70 ... Guide member 71 ... Guide 72 ... Shaft 73 ... Guide inner ring 74 ... Guide outer ring 75 ... Guide ball

(1) The transmission device according to the present invention is arranged around an input shaft that is rotated around an axis by the transmitted power and an eccentric axis that is eccentric to the axis, and is arranged with the rotation of the input shaft. An internal gear having a plurality of internal teeth that operates and is arranged at intervals in the circumferential direction that orbits the eccentric axis is arranged so as to face the internal gear on one side in the axial direction. Along with this, an external gear that is rotatably arranged around the axis and has a plurality of external teeth that can mesh with the plurality of internal teeth, and an output shaft that rotates around the axis as the external gear rotates. The internal gear is fixed to a fixed plate arranged so as to face the internal gear on the other side in the axial direction, and by restraining the rotation of the internal gear, the internal gear swings eccentrically about the axis. A guide member for guiding the internal gear is provided, and the external gear has a number of teeth different from the number of the internal gear. The internal gear is provided with the internal gear, and the external gear is provided in the radial direction. A gear body that surrounds from the outside, an internal gear plate that is arranged so as to face the fixed plate and has the gear body formed on the outer peripheral edge side, and the internal gear so as to open at least toward the fixed plate side. The guide member includes a storage recess formed in the plate, the guide member is arranged in the storage recess, and the guide portion is provided with a guide portion that can be inscribed with respect to the inner wall surface of the storage recess. It is characterized in that it is arranged in the accommodating recess so as to be eccentric by the amount of eccentricity between the axis and the eccentric axis with respect to the center line of the accommodating recess.

Further, the guide portion arranged in the accommodating recess is eccentric with respect to the center line of the accommodating recess by the amount of eccentricity between the axis and the eccentric axis. Therefore, even if the internal gear behaves as if it rotates eccentrically with the rotation of the input shaft, the inner wall surface of the accommodating recess and the guide portion come into contact with each other, so that the rotation of the internal gear can be appropriately restrained. .. In addition, the internal gear can be eccentrically swung while the guide portion is inscribed with respect to the inner wall surface of the accommodating recess. Therefore, the internal gear can be eccentrically swung as if it rotates eccentrically around the guide portion while guiding the movement of the internal gear using the guide portion.
In this way, since the eccentric swing can be performed while guiding the movement of the internal gear by using the guide portion, the eccentric swing can be performed in a stable state with less rattling of the internal gear, and the eccentric swing can be performed from the input shaft. Power can be efficiently transmitted to the output shaft.

( 2 ) The guide portion surrounds the shaft portion fixed to the fixing plate, the guide inner ring portion arranged so as to surround the shaft portion from the outside in the radial direction, and the guide inner ring portion from the outside in the radial direction. A guide outer ring portion arranged in such a manner and a plurality of guide ball portions rotatably held between the guide inner ring portion and the guide outer ring portion are provided, and the guide outer ring portion is formed of the accommodating recess. It may be inscribed on the inner wall surface.

( 3 ) The internal tooth may have a circular outer shape in a plan view seen from the eccentric axis direction, and may have a rotating body that can rotate.

( 4 ) The rolling element may be a ball.

( 5 ) The external teeth may be formed in a tooth profile along a trochoidal curve.

( 6 ) An input inner ring portion that is integrally combined with the input shaft and is arranged around the eccentric axis, and an input outer ring that is arranged so as to surround the input inner ring portion from the outside in the radial direction. A portion and a plurality of input balls rotatably held between the input inner ring portion and the input outer ring portion are provided, and the inner gear is integrated with the input outer ring portion. May be combined.

( 7 ) The output shaft may be integrally formed with the external gear.

Claims (8)

An input shaft that rotates around the axis by the transmitted power,
A plurality of internal teeth arranged around the eccentric axis eccentric with respect to the axis, operating with the rotation of the input shaft, and arranged at intervals in the circumferential direction around the eccentric axis. With internal gears,
An outer gear that is arranged so as to face the internal gear on one side in the axial direction, is rotatably arranged around the axial line, and has a plurality of external teeth that can mesh with the plurality of the internal teeth. With gears
An output shaft that rotates around the axis as the external gear rotates, and
The internal gear is fixed to a fixed plate arranged so as to face the internal gear on the other side in the axial direction, and by restraining the rotation of the internal gear, the internal gear swings eccentrically about the axis. With a guide member that guides
The transmission device is characterized in that the external teeth have a number of teeth different from the number of internal teeth. In the transmission device according to claim 1,
The internal gear is
A gear body provided with the internal teeth and surrounding the external gear from the outside in the radial direction,
An internal gear plate arranged so as to face the fixed plate and having the gear body formed on the outer peripheral edge side.
A housing recess formed in the internal gear plate so as to open at least toward the fixed plate side is provided.
The guide member is arranged in the accommodating recess and includes a guide portion that can be inscribed with respect to the inner wall surface of the accommodating recess.
The guide portion is arranged in the accommodating recess so as to be eccentric with respect to the center line of the accommodating recess by the amount of eccentricity between the axis and the eccentric axis. In the transmission device according to claim 2,
The guide unit
The shaft portion fixed to the fixing plate and
A guide inner ring portion arranged so as to surround the shaft portion from the outside in the radial direction, and a guide inner ring portion.
A guide outer ring portion arranged so as to surround the guide inner ring portion from the outside in the radial direction, and a guide outer ring portion.
A plurality of guide ball portions rotatably held between the guide inner ring portion and the guide outer ring portion are provided.
A transmission device in which the guide outer ring portion is inscribed with respect to the inner wall surface of the accommodating recess. In the transmission device according to any one of claims 1 to 3,
The internal tooth is a transmission device having a circular outer shape in a plan view seen from the eccentric axis direction and having a rotating body capable of rotating. In the transmission device according to claim 4,
The rolling element is a transmission device, which is a ball. In the transmission device according to any one of claims 1 to 5,
A transmission device in which the external teeth are formed in a tooth profile along a trochoidal curve. In the transmission device according to any one of claims 1 to 6,
An input inner ring portion that is integrally combined with the input shaft and is arranged around the eccentric axis.
An input outer ring portion arranged so as to surround the input inner ring portion from the outside in the radial direction, and an input outer ring portion.
A plurality of input balls rotatably held between the input inner ring portion and the input outer ring portion are provided.
A transmission device in which the internal gear is integrally combined with the input outer ring portion. In the transmission device according to any one of claims 1 to 7.
The output shaft is a transmission device integrally formed with the external gear.

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