JP2022134901A - Transmitter - Google Patents

Abstract

To provide a transmitter capable of securing rigidity of a ring gear.SOLUTION: A transmitter 100 comprises: a ring gear 42 having a first gear 41, an outer peripheral surface provided with external teeth 422 that mesh with the first gear 41, and an inner peripheral surface provided with internal teeth 424; a second gear 50 meshing with the internal teeth 424 of the ring gear 42; and thrust bearing means 45 arranged on the inner tooth 424 side with respect to the axis of the second gear 50 and receiving a thrust load.SELECTED DRAWING: Figure 1

Description

The present invention relates to transmission devices.

2. Description of the Related Art A transmission device is known that reduces rotation input via a ring gear and outputs the rotation. For example, Patent Literature 1 describes a transmission device that decelerates and outputs rotation input via a ring gear having external and internal teeth. This transmission device includes a ring gear having external and internal teeth that mesh with a first gear connected to a drive source, a second gear that meshes with the internal teeth of the ring gear, and a reduction section that reduces the input from the second gear. and The ring gear is rotatably supported by bearings arranged radially inward of the internal teeth.

JP 2019-158143 A

The present inventor has studied a transmission device that transmits rotation via a ring gear, and has obtained the following recognition. A ring gear having external teeth and internal teeth desirably has sufficient rigidity against a load applied to the external teeth from the viewpoint of ensuring rotational accuracy. However, in the transmission device disclosed in Patent Document 1, since the ring gear is supported by the bearings arranged inside the internal gear, it is difficult to ensure the rigidity of the ring gear.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transmission device capable of ensuring the rigidity of a ring gear.

In order to solve the above problems, a transmission device according to one aspect of the present invention includes a first gear, an outer peripheral surface provided with external teeth that mesh with the first gear, an inner peripheral surface provided with internal teeth, , a second gear meshing with the inner teeth of the ring gear, and thrust bearing means arranged on the inner tooth side of the axis of the second gear and receiving a thrust load.

Arbitrary combinations of the above constituent elements, and mutually replacing the constituent elements and expressions of the present invention in methods, systems, etc. are also effective as aspects of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, the transmission device which can ensure the rigidity of a ring gear can be provided.

1 is a side sectional view schematically showing a transmission device according to a first embodiment; FIG. It is a sectional side view showing roughly the transmission device concerning a 2nd embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on preferred embodiments with reference to the drawings. In the embodiment and modified examples, the same or equivalent constituent elements and members are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Also, in each drawing, some of the members that are not important for explaining the embodiments are omitted.

Also, terms including ordinal numbers such as first, second, etc. are used to describe various components, but these terms are used only for the purpose of distinguishing one component from other components, and the terms The constituent elements are not limited by

[First embodiment]
The configuration of the transmission device 100 according to the first embodiment of the present disclosure will be described below with reference to the drawings. FIG. 1 is a side sectional view schematically showing a transmission device 100 according to this embodiment. The transmission device 100 of this example can be applied, for example, to rotate the wrist of an industrial robot or a turntable. The transmission device 100 decelerates and transmits the rotation input from the drive source 6, and outputs it to a mating device (not shown) to be driven. The transmission device 100 has a gear unit 4 that transmits rotation from the drive source 6 and a reduction section 10 .

As shown in FIG. 1, the direction along the central axis La of the internal gear 16 of the reduction section 10, which will be described later, is called the "axial direction", and the circumferential direction and the radial direction of a circle centered on the central axis La are They are referred to as "circumferential direction" and "radial direction", respectively. Further, hereinafter, for the sake of convenience, one side in the axial direction (right side in the drawing) will be referred to as the input side, and the other side (left side in the drawing) will be referred to as the anti-input side.

(gear unit)
The gear unit 4 will be described with reference to FIG. The gear unit 4 comprises a first gear 41 , a ring gear 42 , a connecting member 44 , bearing means 45 and 46 and casings 22 and 23 . The casings 22 , 23 function as outer shells for housing the gear unit 4 , particularly the ring gear 42 . The casings 22 , 23 include a first casing 22 , a disk-shaped second casing 23 closing the input side of the first casing 22 , and a third casing 16 . The outer peripheral portion 232 of the second casing 23 is coupled to the input side end portion 222 of the first casing 22 by coupling means such as bolts B2. The second casing 23 functions as a base for supporting the bearing means 45,46.

The first gear is connected to the output shaft 62 of the driving source 6 , and rotational driving force is input from the driving source 6 to the first gear 41 . The drive source 6 is, for example, a motor.

The ring gear 42 has an outer peripheral surface provided with external teeth 422 that mesh with the first gear 41 and an inner peripheral surface provided with internal teeth 424 . A plate-like intermediate portion 426 is provided radially inside the external teeth 422 , and internal teeth 424 are provided inside the intermediate portion 426 . The intermediate portion 426 has a plurality of through holes 427 axially drilled at positions offset from the radial center.

In this example, the ring gear 42 is a hollow annular member having an outer peripheral surface and an inner peripheral surface as a whole, and an inner peripheral stepped portion 425 to which the connecting member 44 is connected is formed on the inner peripheral side. The ring gear 42 is rotatably supported about the central axis La by bearing means 45 and 46 via a connecting member 44 .

The configuration of the first gear 41 and the external teeth 422 is not limited, but in this example, the first gear 41 and the external teeth 422 are bevel gears. The internal teeth 424 mesh with the second gear 50 of the reduction section 10 and transmit the rotation of the ring gear 42 to the reduction section 10 via the second gear 50 . Although the configuration of the internal teeth 424 and the second gear 50 is not limited, in this example the internal teeth 424 and the second gear 50 are spur gears. For example, these may be helical gears.

In this embodiment, three second gears 50 are arranged at intervals of 120° in the circumferential direction at positions offset from the central axis La. Axial centers Lb (rotational centers) of the three second gears 50 extend in the axial direction.

The bearing means 45 , 46 include thrust bearing means 45 for receiving the thrust load of the ring gear 42 and radial bearing means 46 for receiving the radial load of the ring gear 42 . The configuration of the thrust bearing means 45 is not limited. In this example, the thrust bearing means 45 has a first bearing ring 453 and a second bearing ring 454 that face each other in the axial direction (thrust direction) with a plurality of rolling elements 452 interposed therebetween. In this example, the plurality of rolling elements 452 are cylindrical bodies (rollers) arranged at predetermined intervals in the circumferential direction. The plurality of rolling elements 452 are positionally regulated within a predetermined range by a retainer (not shown). The first bearing ring 453 and the second bearing ring 454 are hollow disk-shaped members.

In this example, the thrust bearing means 45 overlaps the radial bearing means 46 when viewed in the radial direction. In this case, it is possible to reduce the thickness in the axial direction as compared with a configuration in which they do not overlap when viewed in the radial direction. The thrust bearing means 45 is arranged radially away from the radial bearing means 46 . The axial extent of the thrust bearing means 45 partially or fully overlaps the axial extent of the radial bearing means 46 .

The thrust bearing means 45 is arranged on the side of the axial center Lb of the second gear 50 where the internal teeth 424 are provided. In particular, the thrust bearing means 45 is arranged radially outward of the axis Lb. In the example of FIG. 1, the thrust bearing means 45 is at least partially arranged radially outside the internal teeth 424 . Furthermore, the entire thrust bearing means 45 is arranged radially outwardly of the internal teeth 424 . In this case, the thrust rigidity of the ring gear 42 can be increased by arranging the thrust bearing means 45 radially outward. By increasing the thrust rigidity, the bending of the ring gear 42 is reduced, and the decrease in rotational accuracy caused by the bending can be suppressed. Moreover, under the condition of constant rigidity, the ring gear 42 can be thinned, which is advantageous for weight reduction.

The connection member 44 is a hollow disk-shaped member connected to the inner peripheral side of the ring gear 42 . The connecting member 44 has an outer peripheral fitting portion 442 fitted to the inner peripheral stepped portion 425 of the ring gear 42 and an inner peripheral fitting portion 444 fixed to the radial bearing means 46 . The connecting member 44 has a plurality of internal threads 445 axially drilled at locations offset from the radial center. The plurality of female threads 445 are provided at predetermined intervals in the circumferential direction at positions overlapping the plurality of through holes 427 of the ring gear 42 when viewed in the axial direction. The connection member 44 is fixed to the ring gear 42 by screwing a bolt B3 passing through the through hole 427 into the female screw 445 . In this example, the neck of the bolt B3 is hooked on a seat that is stepped around the inner peripheral surface of the through hole 427 . In this example, the inner peripheral fitting portion 444 is the inner cylindrical surface of the hollow portion of the connecting member 44 and has a shape that allows the radial bearing means 46 to fit therein.

As shown in FIG. 1, the thrust bearing means 45 overlaps the external teeth 422 when viewed axially. In this case, since the axial position of the external teeth 422 is stabilized, it is possible to suppress noise and accuracy deterioration due to bending of the ring gear 42 . The first bearing ring 453 is axially connected to the second casing 23 . In this case, the number of parts is reduced, which is advantageous for thinning. Specifically, the first bearing ring 453 of the thrust bearing means 45 is fixed in a state of being fitted radially inward of the peripheral stepped portion 233 formed on the non-input side of the second casing 23 . The second bearing ring 454 of the thrust bearing means 45 is fixed while being fitted to the radially outer side of the peripheral stepped portion 423 formed on the input side of the ring gear 42 . In this example, ring gear 42 is directly coupled to second bearing ring 454 . In this case, the number of parts is reduced, which is advantageous for thinning. At least a portion of the thrust bearing means 45 is surrounded by a peripheral wall portion 235 formed on the non-input side of the second casing 23 .

The configuration of the radial bearing means 46 is not limited. In this example the radial bearing means 46 is a deep groove ball bearing having rolling elements 462 , an inner ring 463 and an outer ring 464 . The inner ring 463 is fitted and fixed to the outer peripheral surface of the hollow inner cylindrical portion 236 that protrudes on the counter-input side of the second casing 23 . In this example, the input side of the inner ring 463 is positioned in contact with a seat that is stepped around the outer peripheral surface of the inner cylindrical portion 236 , and the non-input side of the inner ring 463 is positioned on the outer peripheral surface of the inner cylindrical portion 236 . Axial movement is restricted by abutting on the snap ring 237 fitted and fixed.

In this example, the input side of the outer ring 464 is positioned in contact with a seat provided stepwise on the inner peripheral surface of the inner peripheral fitting portion 444 of the connecting member 44, and the non-input side of the outer ring 464 Axial movement is restricted by abutting on a snap ring 238 fitted and fixed to the inner peripheral surface of the peripheral fitting portion 444 .

(Reduction part)
Next, the deceleration section 10 will be described with reference to FIGS. 1 and 2. FIG. The speed reduction unit 10 of the present embodiment is a so-called distribution type eccentric oscillating gear mechanism in which the crankshaft (eccentric body shaft) is arranged at a position offset from the axial center of the internal gear. The deceleration unit 10 rotates one of the internal gear and the external gear by oscillating the external gear that meshes with the internal gear, and outputs the generated rotation component from the output member to the driven device. configured as

The reduction section 10 includes an eccentric shaft 12, an external gear 14, a third casing 16 (internal gear 16), carriers 18 and 20, a first casing 22, main bearings 24 and 26, and a center pipe 52. and a second gear 50.

The carriers 18 , 20 include a first carrier 18 arranged on the non-input side of the external gear 14 and a second carrier 20 arranged on the input side of the external gear 14 . The main bearings 24 and 26 consist of a first main bearing 24 arranged on the non-input side of the external gear 14 and a second main bearing 26 arranged on the input side of the external gear 14. include. In this example, the main bearings 24, 26 are tapered roller bearings. The third casing 16 (internal gear 16 ) has a hollow cylindrical shape, and has a recess 224 that accommodates the outer ring of the first main bearing 24 and a recess 226 that accommodates the outer ring of the second main bearing 26 . The carriers 18 and 20 are rotatably supported by the third casing 16 (the internal gear 16) via a first main bearing 24 and a second main bearing 26. As shown in FIG. The carriers 18, 20 are generally hollow discs or cylinders. Carriers 18 and 20 rotatably support eccentric shaft 12 via eccentric shaft bearings 34 .

The carriers 18,20 have central holes 183,203 formed in their radial centers. The central holes 183, 203 are generally circular and extend axially therethrough. Carriers 18 , 20 have eccentric shaft bores 182 , 202 to accommodate eccentric shaft bearings 34 . The eccentric body shaft holes 182, 202 are circular as a whole and penetrate in the axial direction. The carrier 18 has three eccentric shaft holes 182 arranged at positions offset from the radial center. The three eccentric body shaft holes 182 are arranged at regular intervals of 120° in the circumferential direction. The carrier 20 has three eccentric shaft holes 202 arranged at positions offset from the radial center. The three eccentric body shaft holes 202 are arranged at regular intervals of 120° in the circumferential direction.

(eccentric shaft)
Three eccentric shafts 12 are arranged at positions offset from the central axis La of the internal gear 16 . The three eccentric shafts 12 are arranged at regular intervals of 120° in the circumferential direction. Only one eccentric shaft 12 is shown in FIG. The eccentric shaft 12 has a plurality of eccentric portions 122 for oscillating the external gear 14 . The axis of the eccentric portion 122 is eccentric with respect to the rotation center line of the eccentric body shaft 12 . In this embodiment, two eccentric portions 122 are provided, and the eccentric phases of adjacent eccentric portions 122 are shifted by 180°. The eccentric shaft 12 is inserted through the center of the second gear 50 and supports the second gear 50 .

The eccentric shaft 12 is supported by the first carrier 18 and the second carrier 20 via a pair of eccentric shaft bearings 34 . The non-input side eccentric shaft bearing 34 is provided between the eccentric shaft 12 and the eccentric shaft hole 182 of the first carrier 18 on the non-input side of the external gear 14 . The input side eccentric shaft bearing 34 is provided between the eccentric shaft 12 and the eccentric shaft hole 202 of the second carrier 20 on the input side of the external gear 14 . The eccentric shaft bearing 34 in this example is a tapered roller bearing.

(second gear)
Rotational power is transmitted to the second gear 50 from a drive source 6 (not shown) through the gear unit 4 . In this embodiment, the second gear 50 is provided adjacent to one end side of each eccentric shaft 12 . The second gear 50 is, for example, spline-connected to each eccentric shaft 12 and integrated in the rotational direction. Only one second gear 50 is shown in FIG. The second gear 50 meshes with the internal teeth 424 .

(Internal gear)
The internal gear 16 meshes with the external gear 14 . The internal gear 16 is provided on the inner circumference of the third casing 16 . The internal gear 16 of this embodiment has an annular internal gear body 162 fixed to the inner peripheral portion of the third casing 16 and an outer pin 17 . The input-side end face of the internal gear body 162 axially contacts a projecting portion 227 projecting toward the inner circumference of the third casing 16, and these are connected by a connector such as a bolt B5.

The outer pins 17 are arranged in respective pin grooves formed in the internal gear body 162 at intervals in the circumferential direction. The outer pin 17 is a cylindrical pin member rotatably supported by the internal gear body 162 . The outer pin 17 may be a hollow member, but is a solid member in this embodiment. The outer pin 17 constitutes the inner teeth of the internal gear 16 . The number of external pins 17 (the number of internal teeth) of the internal gear 16 is slightly greater than the number of external teeth of the external gear 14 (by one in this example).

(external gear)
The external gear 14 is individually provided corresponding to each of the plurality of eccentric portions 122 . The external gear 14 is rotatably supported by the corresponding eccentric portion 122 via the eccentric bearing 32 (eccentric roller). In the external gear 14, three shaft holes 144 and three swing holes 143 are formed at predetermined intervals at positions offset from the axis.

The shaft holes 144 are provided at 120° intervals at the same radial position. The shaft hole 144 penetrates in the axial direction, and the shaft portion 185 is inserted therethrough. The shaft hole 144 is formed larger than the outer diameter of the shaft portion 185 and has a size that does not come into contact with the shaft portion 185 .

The swing holes 143 are provided at 120° intervals at the same radial position. The swing hole 143 penetrates in the axial direction, and the eccentric portion 122 of the eccentric body shaft 12 is inserted therethrough. The swing hole 143 is formed larger than the outer diameter of the eccentric portion 122 , and a plurality of eccentric bearings 32 are interposed between the swing hole 143 and the eccentric portion 122 . The plurality of eccentric bearings 32 are arranged around the eccentric portion 122 at substantially equal intervals, and smoothly transmit the eccentric motion of the eccentric portion 122 to the swing hole 143 .

The external gear 14 is provided with a central hole 142 through which the center pipe 52 passes. The central hole 142 is a hole provided in the radial center of the external gear 14 , is formed larger than the outermost diameter of the center pipe 52 , and has a size that does not come into contact with the center pipe 52 . Although the shape of the central hole 142 is not limited, the central hole 142 in this example is circular.

Waveform teeth are formed on the outer periphery of the external gear 14, and the teeth move while being in contact with the internal gear 16, thereby causing the external gear 14 to oscillate within a plane normal to the central axis. It is possible.

The first carrier 18 and the second carrier 20 are connected via the shaft portion 185 . The shaft portion 185 is provided at a position radially offset from the axis of the external gear 14 . The shaft portion 185 in FIG. 1 is a portion that extends axially from the first carrier 18 toward the second carrier 20 and is integrally formed with the first carrier 18 . The shaft portion 185 is inserted through a shaft hole 144 formed through the external gear 14 with a gap therebetween.

The shaft portion 185 is fixed to the second carrier 20 with its distal end in contact with the end surface of the second carrier 20 on the opposite side to the input side. When the shaft portion 185 is fixed to the second carrier 20, it is positioned by a positioning pin (not shown) and fixed by a bolt B1. Shaft portion 185 functions as a connection that contributes to the connection between first carrier 18 and second carrier 20 .

An oil seal 28 is provided between the first carrier 18 and the internal gear 16 . The oil seal 28 is arranged on the non-input side of the first main bearing 24 .

One of the first carrier 18 and the internal gear 16 functions as an output member that outputs rotational power to the driven device, and the other functions as a fixed member that is fixed to an external member for supporting the reduction section 10. . In this embodiment, the output member is the first carrier 18 and the fixed member is the internal gear 16 . The internal gear 16 may be the output member and the first carrier 18 may be the fixed member.

The operation of the transmission device 100 configured as above will be described. When rotation is input from the drive source 6 to the first gear 41 , the ring gear 42 rotates around the center axis La in conjunction with the rotation of the first gear 41 . Rotational power of the ring gear 42 is distributed to the three second gears 50 meshing with the internal teeth 424 of the ring gear 42, and the three second gears 50 rotate in the same phase. When the three second gears 50 rotate, the eccentric portion 122 of the eccentric shaft 12 rotates around the rotation center line passing through the eccentric shaft 12, and the eccentric portion 122 causes the external gear 14 to oscillate. When the external gear 14 oscillates, the meshing positions of the external pin 17 of the external gear 14 and the internal gear 16 are sequentially displaced. As a result, each time the eccentric shaft 12 rotates, the number of teeth of the external gear 14 and the number of the internal gear 16 corresponding to the difference between the number of teeth of the external gear 14 and the number of the external pins 17 of the internal gear 16 are increased. One rotation occurs. In this embodiment, the external gear 14 rotates and the first carrier 18 outputs reduced rotation. A center pipe 52 is fixed to the first carrier 18 , and the center pipe 52 rotates integrally with the first carrier 18 .

Features of the transmission device 100 configured as described above will be described. The transmission device 100 of this embodiment includes a ring gear 42 having a first gear 41, an outer peripheral surface provided with external teeth 422 that mesh with the first gear 41, and an inner peripheral surface provided with internal teeth 424. , the second gear 50 that meshes with the internal teeth 424 of the ring gear 42, the reduction section 10 that decelerates and outputs the input from the second gear 50, and the internal teeth 424 of the axial center Lb of the second gear 50. and thrust bearing means 45 arranged to receive the thrust load.

According to this configuration, the thrust rigidity of the ring gear 42 can be increased by arranging the thrust bearing means 45 on the inner tooth 424 side of the axis Lb of the second gear 50 in the radial direction. By increasing the thrust rigidity, the bending of the ring gear 42 is reduced, and the decrease in rotational accuracy caused by the bending can be suppressed. Moreover, under the condition of constant rigidity, the ring gear 42 can be thinned, which is advantageous for weight reduction. As a result, a transmission device capable of ensuring the rigidity of the ring gear 42 can be provided.
The above is the description of the first embodiment.

[Second embodiment]
A configuration of a transmission device 100 according to a second embodiment of the present disclosure will be described with reference to FIG. FIG. 2 is a side sectional view showing the transmission device 100 according to the second embodiment. The transmission device 100 of this embodiment differs from that of the first embodiment in that the thrust bearing means and the radial bearing means are configured as an integrated bearing, and the rest of the configuration is the same. Duplicate description will be omitted, and the configuration different from the first embodiment will be mainly described.

In the gear unit 4 of this embodiment, the thrust bearing means 45, the radial bearing means 46 and the connecting member 44 are eliminated from the first embodiment, and an integrated bearing 47 is provided. The integrated bearing 47 may be a cross-roller bearing, a double-row angular bearing, or the like, as long as the thrust bearing means and the radial bearing means are integrated as a bearing. In this example, integrated bearing 47 is a cross roller bearing. The integrated bearing 47 has a first bearing ring 473 (inner ring) and a second bearing ring 474 (outer ring) that face each other in the radial direction with the rolling elements 472 interposed therebetween. The rolling elements 472 are cylindrical rollers.

The first bearing ring 473 is arranged radially inside the rolling elements 472 , and is fitted and fixed to the outer peripheral surface of the annular projecting portion 234 projecting on the opposite input side of the second casing 23 . In this example, the input side of the first bearing ring 473 is positioned by coming into contact with a seat provided around the outer peripheral surface of the annular projecting portion 234 in a stepped manner. The first bearing ring 473 has a plurality of through holes 476 axially drilled at positions offset from the radial center. A plurality of through holes 476 are provided at predetermined intervals in the circumferential direction.

The second casing 23 has a plurality of internal threads 239 axially drilled at positions offset from the radial center. The plurality of female threads 239 are provided at predetermined intervals in the circumferential direction at positions overlapping the plurality of through holes 476 of the first bearing ring 473 when viewed in the axial direction. The first bearing ring 473 is fixed to the second casing 23 by screwing a bolt B<b>4 passing through the through hole 476 into the female thread 239 . In this example, the neck of the bolt B3 hangs on a seat that is stepped around the inner peripheral surface of the through hole 476 .

The second bearing ring 474 is an annular member arranged radially outside the rolling elements 472 and connected to the inner peripheral side of the ring gear 42 . In particular, the second bearing ring 474 fits into the inner peripheral stepped portion 425 of the ring gear 42 . The second race 474 has a plurality of internal threads 475 axially drilled at locations offset from the radial center. The plurality of female threads 475 are provided at predetermined intervals in the circumferential direction at positions overlapping the plurality of through holes 427 of the ring gear 42 when viewed in the axial direction. The second bearing ring 474 is fixed to the ring gear 42 by screwing a bolt B<b>3 passing through the through hole 427 into the female thread 475 . In this example, the neck of the bolt B3 is hooked on a seat that is stepped around the inner peripheral surface of the through hole 427 . As shown in FIG. 2 , the first bearing ring 473 is arranged radially inwardly with respect to the internal teeth 424 , the rolling elements 472 are arranged so as to axially overlap the internal teeth 424 , and the second raceway The ring 474 is arranged radially outwardly with respect to the internal teeth 424 . That is, at least a portion of the integrated bearing 47 is arranged radially outward of the internal teeth 424 .

The second embodiment operates in the same manner as the first embodiment, and has similar actions and effects. In addition, in the transmission device 100 of the present embodiment, the thrust bearing means and the radial bearing means are configured as an integral bearing, so the number of parts can be reduced and the manufacturing man-hours can be reduced. Moreover, since these are integrated, it is possible to easily realize a configuration in which the thrust bearing means 45 overlaps the radial bearing means 46 when viewed from the radial direction.

Exemplary embodiments of the present invention have been described above in detail. All of the above-described embodiments merely show specific examples for carrying out the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as changes, additions, and deletions of constituent elements can be made without departing from the spirit of the invention defined in the claims. It is possible. In the above-described embodiment, descriptions such as "of the embodiment", "in the embodiment", etc. are added to the contents that allow such design changes. Changes are not unacceptable. Moreover, the hatching attached to the cross section of the drawing does not limit the material of the hatched object.

Modifications will be described below. In the drawings and description of the modified example, the same reference numerals are given to the same or equivalent components and members as the embodiment. Explanations that overlap with the embodiment will be omitted as appropriate, and the explanation will focus on the configuration that is different from the embodiment.

[Modification]
In the description of the embodiment, an example in which the speed reduction unit 10 is a so-called distributed gear mechanism is shown, but the gear mechanism of the speed reduction unit 10 is not limited to this. For example, the transmission device of the present disclosure can be applied to a center crank type gear mechanism in which the eccentric shaft (crank shaft) is arranged on the rotation center axis of the internal gear, a simple planetary gear reduction device, a flexural meshing It can also be applied to various known speed reducers such as a type speed reducer and a parallel shaft speed reducer.

Although the number of eccentric shafts 12 and second gears 50 is three in the description of the embodiment, the number of eccentric shafts 12 and second gears 50 may be one, two, or four or more. .

Although the number of the external gears 14 is two in the description of the embodiment, the number of the external gears 14 may be one or three or more.

There is no limitation on the configuration of each bearing of the gear device. Each bearing may have a different configuration from the embodiment.

Each of the modifications described above has the same actions and effects as the embodiment.

Any combination of the components and variations of the above-described embodiments are also useful as embodiments of the present invention. A new embodiment resulting from the combination has the effects of each of the combined embodiments and modifications.

4 gear unit 10 reduction section 41 first gear 42 ring gear 45 thrust bearing means 46 radial bearing means 50 second gear 422 external teeth 424 internal teeth 452, 472 rolling elements 453, 473 first race, 454, 474 second race, 100 transmission;

Claims (7)

a first gear;
a ring gear having an outer peripheral surface provided with external teeth that mesh with the first gear and an inner peripheral surface provided with internal teeth;
a second gear meshing with the internal teeth of the ring gear;
a thrust bearing means arranged on the inner tooth side of the shaft center of the second gear and receiving a thrust load;
A transmission device comprising: having radial bearing means for receiving a radial load;
2. A transmission according to claim 1, wherein said thrust bearing means radially overlaps said radial bearing means. 3. A transmission according to claim 2, wherein said thrust bearing means and said radial bearing means are constructed as an integral bearing. The thrust bearing means has a first bearing ring and a second bearing ring facing each other across the rolling element,
4. The transmission device according to any one of claims 1 to 3, wherein the ring gear is directly connected to the second bearing ring. Having a casing that houses the ring gear,
5. A transmission device according to claim 4, wherein said first bearing ring is axially connected to said casing. 6. A transmission device according to any one of claims 1 to 5, wherein at least a portion of said thrust bearing means is arranged radially outwardly of said internal teeth. 7. A transmission as claimed in any preceding claim, wherein the thrust bearing means overlaps the external teeth when viewed axially.

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