JP3696713B2 - Reduction gear - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reduction gear suitable for use in a turning device such as a hydraulic excavator or a hydraulic crane.
[0002]
[Prior art]
In general, a turning device for turning an upper turning body such as a hydraulic excavator or a hydraulic crane on the lower traveling body is equipped with a speed reduction device for increasing the output of a rotation source.
[0003]
Therefore, an example in which this type of prior art reduction device is applied to a swing device for a hydraulic excavator shown in FIGS. 4 and 5 will be described.
[0004]
In the figure, reference numeral 1 denotes a turning device disposed between a lower traveling body and an upper turning body (both not shown) of a hydraulic excavator. The turning device 1 supplies and discharges pressure oil from the outside. Thus, the hydraulic motor 2 as a rotation source that rotationally drives the output shaft 2 </ b> A, and the speed reducer 4 that decelerates the rotation of the output shaft 2 </ b> A of the hydraulic motor 2 and transmits it to the turning wheel 3.
[0005]
Here, the turning wheel 3 is provided between the round body 5 of the lower traveling body and the turning frame 6 of the upper turning body, and an inner ring 7 fixed to the round body 5 and an outer ring 8 fixed to the turning frame 6. And a plurality of steel balls 9 (only one is shown) disposed between the outer ring 8 and the inner ring 7. Then, the outer ring 8 rotates around the inner ring 7 via each steel ball 9, and the turning frame 6 rotates together with the outer ring 8, whereby the upper turning body turns with respect to the lower traveling body. .
[0006]
Reference numeral 10 denotes a grease bath provided on the inner peripheral side of the swivel wheel 3. The grease bath 10 is formed in a concave ring shape on the inner peripheral surface of the round body 5 and formed on the inner peripheral side of the inner ring 7. In addition, grease for lubricating the meshing portion between the inner teeth 7A and the pinion 19 described later is held.
[0007]
Reference numeral 11 denotes a housing which forms an outer shell of the speed reduction device 4 and is arranged on the revolving frame 6 in the vertical direction. The housing 11 includes an upper housing 13 having an inner peripheral side serving as a speed reduction mechanism accommodating portion 12, and an inner peripheral side. And a lower housing 15 provided with a shaft support portion 14. The hydraulic motor 2 is fixed to the upper end side of the upper housing 13. The upper housing 13 and the lower housing 15 are fixed by a plurality of bolts, and the lower housing 15 is fixed on the revolving frame 6 by a plurality of bolts. Here, inner teeth 13 </ b> A are formed on the inner peripheral side of the upper housing 13 over the entire periphery.
[0008]
Reference numeral 16 denotes an upper bearing provided between the shaft support portion 14 and the output shaft 18 provided in the lower housing 15, and the upper bearing 16 is an inner ring fitted to the output shaft 18 as shown in FIG. A tapered roller bearing is configured by 16A, an outer ring 16B attached to the upper center of the shaft support portion 14, and a plurality of rolling elements 16C provided between the inner ring 16A and the outer ring 16B. Reference numeral 17 denotes a lower bearing which is located below the upper bearing 16 and provided between the shaft support portion 14 and the output shaft 18. The lower bearing 17 includes an inner ring 17A fitted to the output shaft 18 and a shaft. The outer ring 17B attached to the lower center of the support portion 14 and a plurality of rolling elements 17C provided between the inner ring 17A and the outer ring 17B constitute a tapered roller bearing.
[0009]
Reference numeral 18 denotes an output shaft that is inserted into the shaft support portion 14 of the lower housing 15 and is rotatably supported by the upper bearing 16 and the lower bearing 17. A planetary gear, which will be described later, is disposed on the outer periphery of the upper end side of the output shaft 18. A tooth portion 18A that is spline-coupled with the carrier 32 of the mechanism 28 is formed, and a screw portion 18B into which a nut member 33 described later is screwed is screwed below the tooth portion 18A. Further, the lower end side of the output shaft 18 protrudes to the lower side of the turning frame 6 to become a pinion 19, and the pinion 19 meshes with internal teeth 7 </ b> A formed on the inner ring 7 of the turning wheel 3. Thus, the output shaft 18 revolves while rotating with the pinion 19 via the inner teeth 7 </ b> A of the inner ring 7, and the revolving force causes the revolving frame 6 to revolve via the housing 11.
[0010]
Reference numeral 20 denotes an annular retainer inserted into the lower end side of the output shaft 18, and the retainer 20 is positioned between the pinion 19 of the output shaft 18 and the lower bearing 17 and holds the inner ring of the lower bearing 17. are doing. Reference numeral 21 denotes an annular partition plate provided between the lower bearing 17 and the retainer 20, and the partition plate 21 is configured such that the grease filled in the grease bath 10 is formed between the internal teeth 7 </ b> A of the swivel wheel 3 and the pinion 19. It is prevented from being ejected by the pumping action due to meshing and entering the housing 11.
[0011]
An annular seal member 22 is provided between the upper bearing 16 and the lower bearing 17 and provided in the housing 11, and the outer peripheral side of the seal member 22 is fitted to the shaft support portion 14 of the lower housing 15. The inner peripheral side is in fluid-tight sliding contact with the output shaft 18 with an appropriate elastic force. The seal member 22 seals the lubricating oil that lubricates the planetary gear mechanisms 23 and 28 and the like in the speed reduction mechanism housing 12 and is isolated from the grease filled in the grease bath 10.
[0012]
Reference numeral 23 denotes a first-stage planetary gear mechanism that is positioned below the hydraulic motor 2 and disposed in the speed reduction mechanism accommodating portion 12 of the upper housing 13, and the planetary gear mechanism 23 is an output shaft 2 </ b> A of the hydraulic motor 2. And a plurality of planetary gears 25 (only one is shown) that revolves around the sun gear 24 while rotating around the sun gear 24 and the inner gear 13A of the upper housing 13. And a carrier 27 which rotatably supports each planetary gear 25 via a pin 26.
[0013]
Reference numeral 28 denotes a second stage planetary gear mechanism that is located below the planetary gear mechanism 23 and is disposed in the speed reduction mechanism accommodating portion 12 of the upper housing 13, and the planetary gear mechanism 28 is a carrier of the planetary gear mechanism 23. 27, a plurality of planetary gears 30 that mesh with the sun gear 29 spline-coupled to the inner teeth and the sun gear 29 and the inner teeth 13A of the upper housing 13 and revolve while rotating around the sun gear 29. (Only one is shown) and a carrier 32 that rotatably supports each planetary gear 30 via a pin 31.
[0014]
The internal teeth formed on the carrier 32 are splined to the tooth portion 18A of the output shaft 18 to transmit the revolution of each planetary gear 30 to the output shaft 18. As a result, the rotation of the output shaft 2A of the hydraulic motor 2 is decelerated in two stages by the planetary gear mechanisms 23 and 28, and the output shaft 18 is rotated with a large torque.
[0015]
Reference numeral 33 denotes a nut member positioned above the upper bearing 16 and disposed on the outer peripheral side of the output shaft 18, and the nut member 33 is screwed into a threaded portion 18 </ b> B of the output shaft 18, whereby the output shaft 18. The upper bearing 16 is positioned in the axial direction with the shaft support portion 14 of the lower housing 15.
[0016]
The speed reduction device 4 according to the prior art has the above-described configuration. When pressure oil is supplied to and discharged from the hydraulic motor 2 from the outside and the output shaft 2A is rotationally driven, this rotation is caused by the planetary gear in the housing 11 of the speed reduction device 4. The mechanisms 23 and 28 are decelerated in two stages, and a high torque torque is transmitted to the output shaft 18.
[0017]
The pinion 19 of the output shaft 18 meshes with the inner teeth 7A of the turning wheel 3, the inner wheel 7 is fixed to the round body 5 of the lower traveling body, and the outer ring 8 is the turning frame 6 of the upper turning body. Since the pinion 19 rotates and revolves via the inner teeth 7A of the inner ring 7, this revolution is transmitted from the output shaft 18 to the revolving frame 6 via the housing 11, and the upper revolving body travels downward. Swirl on the body.
[0018]
[Problems to be solved by the invention]
By the way, in the speed reducer 4 according to the prior art described above, the planetary gear mechanisms 23, 28 and the like are constantly lubricated by the lubricating oil stored in the housing 11, and the planetary gear mechanisms 23, 28 are configured. As shown in FIG. 5, foreign matter A such as wear powder generated by the meshing of the gears settles down in the lubricating oil and enters between the inner ring 16 </ b> A and the outer ring 16 </ b> B of the upper bearing 16. As a result, the rolling elements 16C and the like of the upper bearing 16 are damaged, and the smooth rotation of the output shaft 18 is hindered.
[0019]
Further, when the foreign matter A that has passed through the upper bearing 16 enters the sliding contact portion between the seal member 22 and the output shaft 18, the seal member 22 is worn or damaged at an early stage, and the lubricating oil is extracted from the housing 11. Leaks, the stable operation of the planetary gear mechanisms 23, 28, etc. is impaired.
[0020]
The present invention has been made in view of the above-described problems of the prior art, and can prevent a bearing or the like from being damaged by foreign matter such as wear powder, and can stably operate a rotating shaft or a speed reduction mechanism over a long period of time. An object of the present invention is to provide a speed reducer that can be used.
[0021]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a housing arranged in a vertical direction with an upper side serving as a speed reduction mechanism accommodating portion and a lower side serving as a shaft support portion, and a rotation source provided within the speed reduction mechanism accommodating portion of the housing. A speed reduction mechanism that decelerates the shaft, an output shaft that is provided through the shaft support portion of the housing and that outputs rotation decelerated by the speed reduction mechanism, and is provided on the shaft support portion of the housing so that the output shaft can rotate. The present invention is applied to a reduction gear including a bearing to be supported and a nut member which is provided on the outer peripheral side of the output shaft and is positioned above the bearing and which positions the bearing between the shaft support portion of the housing.
[0022]
A feature of the configuration adopted by the invention of claim 1 is that the foreign matter mixed in the lubricating oil for lubricating the speed reduction mechanism in the housing is prevented from entering the bearing. The diameter is set to be equal to or larger than the diameter of the outer ring constituting the bearing.
[0023]
With this configuration, the upper side of the bearing is covered with a nut member having an outer diameter that is equal to or greater than the diameter of the outer ring constituting the bearing, so even if foreign matter is mixed in the lubricating oil that lubricates the speed reduction mechanism, The nut member can prevent foreign matter from entering the bearing.
[0024]
The invention of claim 2 is characterized in that a tapered surface whose outer peripheral side is gradually inclined downward is provided on the upper surface of the nut member.
[0025]
With such a configuration, the foreign matter dropped on the upper surface of the nut member can be guided to the outer peripheral side of the bearing along the tapered surface.
[0026]
Furthermore, the invention of claim 3 is configured such that the shaft support portion of the housing is provided with an annular recessed groove located on the outer peripheral side of the bearing in order to capture foreign matter scattered from the outer peripheral side of the nut member. There is.
[0027]
With this configuration, the foreign matter mixed in the lubricating oil is scattered from the outer peripheral side of the nut member and captured in the recessed groove. In this case, since the foreign matter trapped in the recessed groove is accumulated in the recessed groove by its own weight, it is possible to prevent the foreign matter from entering the bearing even if the lubricating oil is stirred by the operation of the speed reduction mechanism.
[0028]
According to a fourth aspect of the present invention, a detent pin inserted into a pin hole provided in the nut member is provided on the lower surface of the carrier of the speed reduction mechanism that meshes with the rotating shaft, and the detent pin is at least on the lower surface of the detent mechanism. A part of the bearing faces the upper surface of the inner ring constituting the bearing.
[0029]
With this configuration, for example, even when the detent pin is loosened with respect to the carrier during operation of the speed reduction mechanism, the detent is prevented by the lower surface of the detent pin coming into contact with the upper surface of the inner ring of the bearing. The pin can be prevented from being detached from the carrier, and the nut member can be kept in a non-rotating state.
[0030]
Furthermore, the invention of claim 5 is configured such that the nut member is provided with a plurality of pin holes on a circumference having a certain radius, and the locking pin is inserted into one of the pin holes. It is in.
[0031]
According to the above configuration, the rotation of the nut member with respect to the rotation shaft can be easily performed by inserting the rotation stop pin provided on the carrier of the speed reduction mechanism into one of the plurality of pin holes provided in the nut member. it can.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0033]
1 and 2 show an example in which the speed reducer according to the present invention is used in a swing device for a hydraulic excavator. In the present embodiment, the same components as those in the above-described conventional technology are denoted by the same reference numerals, and the description thereof is omitted.
[0034]
In the figure, reference numeral 41 denotes a speed reduction device according to the present embodiment. A housing 42 of the speed reduction device 41 is similar to the housing 11 according to the prior art, and an upper housing 13 whose inner peripheral side is a speed reduction mechanism accommodating portion 12 and a lower side. Although it comprises a housing 43, the construction of the lower housing 43 is different from that of the prior art.
[0035]
Reference numeral 43 denotes a lower housing applied to the present embodiment instead of the lower housing 15 according to the prior art. The lower housing 43 has an upper end 13 formed by a plurality of bolts at the upper end side, like the lower housing 15 according to the prior art. The lower end side is fixed on the revolving frame 6 with a plurality of bolts. A shaft support portion 44 that supports the output shaft 18 via the upper bearing 16 and the lower bearing 17 is provided on the inner peripheral side of the lower housing 43, but on the upper surface side of the shaft support portion 44. An annular recessed groove 45 is formed.
[0036]
Here, the recessed groove 45 is located on the outer peripheral side of the outer ring 16B of the upper bearing 16 and is recessed over the entire periphery on the upper surface side of the shaft support portion 44, and scatters from the outer peripheral side of the nut member 46 described later. The foreign object A is captured.
[0037]
46 shows a nut member applied to this embodiment in place of the nut member 33 according to the prior art. The nut member 46 is formed in a substantially hollow disk shape as shown in FIG. A female screw that is screwed into the screw portion 18B of the output shaft 18 is screwed. Here, the outer diameter D of the nut member 46 is set to be equal to or larger than the diameter d of the outer ring 16B of the upper bearing 16 (D ≧ d), and the upper bearing 16 is covered from the upper side over the entire circumference. (See FIG. 2).
[0038]
Reference numeral 47 denotes a tapered surface formed on the upper surface of the nut member 46. The tapered surface 47 is formed so as to be gradually inclined downward toward the outer peripheral side, and foreign matter mixed in the lubricating oil sealed in the housing 42. When A falls on the nut member 46 by its own weight, the foreign matter A is guided to the outer peripheral side of the nut member 46.
[0039]
48 are four pin holes drilled in the nut member 46, and each pin hole 48 has a circumference 49 (one point in FIG. 3) having a certain radius from the axial center of the nut member 46. (Indicated by a chain line) with an interval of 90 degrees. The nut member 46 is prevented from rotating with respect to the output shaft 18 by inserting a locking pin 50 (described later) into any one of the pin holes 48.
[0040]
Reference numeral 50 denotes a detent pin provided on the lower surface of the carrier 32 constituting the planetary gear mechanism 28 and extending downward. The detent pin 50 is formed to have a smaller diameter than each pin hole 48 of the nut member 46. The upper end side of the locking pin 50 is press-fitted into a fitting hole 51 formed in the lower surface of the carrier 32, and when the carrier 32 is engaged with the tooth portion 18 </ b> A of the output shaft 18, the locking pin 50. The nut member 46 is prevented from rotating with respect to the output shaft 18 by inserting the lower end side thereof into any one of the pin holes 48 of the nut member 46.
[0041]
In this case, since each pin hole 48 of the nut member 46 is provided on a circumference 49 having a certain radius, when the carrier 32 is engaged with the tooth portion 18A of the output shaft 18, the rotation is stopped. The pin 50 can be reliably inserted into one of the four pin holes 48. As a result, for example, in order to align the locking pin 50 and the pin hole 48, the operation of tightening the nut member 46 into the threaded portion 18B of the output shaft 18 can be made unnecessary, and the locking with respect to the nut member 46 can be easily performed. It is possible to prevent the rotation of the upper bearing 16 and the like from being hindered by excessive tightening of the nut member 46.
[0042]
Further, as shown in FIG. 2, the mounting position with respect to the carrier 32 is considered so that a part of the lower surface 50 </ b> A faces the upper surface of the inner ring 16 </ b> A of the upper bearing 16. Thereby, even when the locking pin 50 is loosened in the fitting hole 51 of the carrier 32, the lower surface 50 </ b> A of the locking pin 50 contacts the upper surface of the inner ring 16 </ b> A of the upper bearing 16. Is prevented from detaching from the carrier 32, and the nut member 46 can be kept in a non-rotating state.
[0043]
The reduction gear 41 according to the present embodiment has the above-described configuration. When pressure oil is supplied to and discharged from the hydraulic motor 2 from the outside, the output shaft 2A rotates. This rotation is caused by the planetary gear mechanism in the housing 42 of the reduction gear 41. The speed is reduced in two stages by 23 and 28, and a high torque torque is transmitted to the output shaft 18. As a result, the pinion 19 revolves while rotating through the inner teeth 7A of the inner ring 7. This revolution is transmitted from the output shaft 18 to the revolving frame 6 via the housing 42, and the upper revolving structure revolves on the lower traveling structure. Perform the action.
[0044]
At this time, the planetary gear mechanisms 23 and 28 that operate to decelerate the rotation of the output shaft 2 </ b> A of the hydraulic motor 2 are always lubricated by the lubricating oil enclosed in the housing 42, thereby constituting the planetary gear mechanisms 23 and 28. Foreign matter A such as wear powder generated by the meshing of each gear settles in the lubricating oil by its own weight.
[0045]
However, in the present embodiment, since the upper side of the upper bearing 16 is covered with the nut member 46 having an outer diameter D that is equal to or larger than the diameter d of the outer ring 16B that constitutes the upper bearing 16, it sinks in the lubricating oil. The foreign matter A reaches the upper surface of the nut member 46 and then scatters to the outer peripheral side of the nut member 46 due to the centrifugal force of the nut member 46 that rotates together with the output shaft 18. Accordingly, the foreign matter A is captured in the recessed groove 45 provided in the shaft support portion 44 of the lower housing 43 without entering the upper bearing 16.
[0046]
In this case, since the tapered surface 47 inclined downward toward the outer peripheral side is formed on the upper surface of the nut member 46, the foreign matter A that has reached the upper surface of the nut member 46 is surely along the tapered surface 47. It can be guided into the recessed groove 45.
[0047]
The foreign matter A trapped in the recessed groove 45 accumulates in the recessed groove 45 at a position lower than the upper surface of the outer ring 16B of the upper bearing 16 due to its own weight. Can be prevented from entering the upper bearing 16 beyond the recessed groove 45.
[0048]
Accordingly, foreign matter A in the lubricating oil can be prevented from entering between the inner ring 16A and the outer ring 16B of the upper bearing 16 and damaging the rolling elements 16C and the like of the upper bearing 16, and the output shaft 18 can be kept for a long time. It can be rotated smoothly. Further, it is possible to prevent foreign matter A from entering the sliding contact portion between the seal member 22 disposed below the upper bearing 16 and the output shaft 18, and the sealing performance of the seal member 22 can be kept good.
[0049]
Further, by setting the outer diameter dimension D of the nut member 46 to be large, it is possible to increase the torque when the nut member 46 is fastened to the threaded portion 18B of the output shaft 18. Thereby, it becomes easy to manage the tightening torque for the nut member 46, and the operation of the upper bearing 16 and the like positioned between the nut member 46 and the shaft support portion 44 of the housing 42 can be stabilized.
[0050]
In addition, in this embodiment, the nut member 46 that positions the upper bearing 16 and the like with the shaft support portion 44 of the housing 42 is used to prevent the foreign matter A mixed in the lubricating oil from entering the upper bearing 16 and the like. Since the structure can be prevented, an increase in the number of parts and the number of assembling steps can be prevented as compared with a case where another part is provided only for preventing foreign matter A from entering the upper bearing 16 or the like.
[0051]
In the above-described embodiment, the speed reduction device including the two-stage planetary gear mechanism has been described as an example. However, the present invention is not limited to this, and the one-stage planetary gear mechanism or the three-stage or more planetary gear is provided. The present invention may be applied to a reduction gear provided with a mechanism, and may further be applied to a reduction gear provided with a reduction gear mechanism of a type that does not use a planetary gear, for example.
[0052]
Moreover, in the said Example, although the case where the upper side bearing 16 and the lower side bearing 17 were used as a bearing which supports the output shaft 18 was mentioned as an example, this invention is not limited to this, One bearing or 3 The output shaft may be supported by more than one bearing.
[0053]
Further, in the above-described embodiment, the case where tapered roller bearings are used as the upper bearing 16 and the lower bearing 17 is described as an example. However, the present invention is not limited to this, and nuts that receive loads in the radial direction and the thrust direction. Other types of bearings such as ball bearings positioned by members may be used.
[0054]
【The invention's effect】
As described above in detail, according to the first aspect of the present invention, the outer diameter of the nut member for positioning the bearing with respect to the shaft support portion of the housing is set to be larger than the diameter of the outer ring constituting the bearing. Even if foreign matter such as wear powder is mixed in the lubricating oil that lubricates the speed reduction mechanism, it is possible to reliably prevent the foreign matter from entering the bearing by the nut member that covers the upper side of the bearing. As a result, the bearing can be prevented from being damaged by foreign matters in the lubricating oil, and the rotating shaft can be smoothly rotated. In addition, it is possible to prevent the seal member disposed below the bearing from being damaged by foreign matter and leaking the lubricating oil from the housing, and the speed reduction mechanism can be stably operated over a long period of time.
[0055]
According to the second aspect of the present invention, since the tapered surface on the outer surface of the nut member is gradually inclined downward on the upper surface of the nut member, the foreign matter dropped on the upper surface of the nut member is moved along the tapered surface on the outer peripheral side of the bearing. Intrusion of foreign matter into the bearing can be more reliably prevented.
[0056]
Furthermore, according to the invention of claim 3, since the shaft support portion of the housing is provided with the annular recessed groove for capturing the foreign matter scattered from the outer peripheral side of the nut member, it is scattered from the outer peripheral side of the nut member. Therefore, even if the lubricating oil is stirred by the operation of the speed reduction mechanism, the foreign matter can be prevented from entering the bearing.
[0057]
According to the invention of claim 4, the lower surface of the carrier of the speed reduction mechanism meshing with the rotation shaft is provided with a rotation stop pin inserted into a pin hole provided in the nut member, and the rotation stop pin is at least on the lower surface thereof. Since a part of the structure faces the upper surface of the inner ring of the bearing, even if the detent pin is loosened with respect to the carrier, for example, during operation of the speed reduction mechanism, the lower surface of the detent pin will be By contacting, the detent pin can be prevented from being detached from the carrier, and the nut member can be maintained in the detent state.
[0058]
Furthermore, according to the invention of claim 5, the nut member is provided with a plurality of pin holes on a circumference having a certain radius, and the rotation stop pin is inserted into one of the pin holes. When the carrier is engaged with the rotating shaft, the detent pin can be reliably inserted into one of the plurality of pin holes. As a result, for example, in order to align the locking pin and the pin hole, the operation of tightening the nut member to the rotating shaft can be eliminated, and the rotation of the nut member can be easily performed, and the nut member can be excessive. It is possible to prevent the smooth rotation of the bearing from being hindered by the proper tightening.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a reduction gear according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part showing an upper bearing, a nut member and the like in FIG. 1 in an enlarged manner.
3 is an enlarged perspective view showing a nut member in FIG. 1. FIG.
FIG. 4 is a longitudinal sectional view showing a reduction gear device according to the prior art.
5 is an enlarged cross-sectional view showing an upper bearing, a nut member and the like in FIG. 5 in an enlarged manner.
[Explanation of symbols]
2 Hydraulic motor (rotation source)
12 Reduction mechanism housing portion 16 Upper bearing 16A Inner ring 16B Outer ring 17 Lower bearing 18 Output shafts 23, 28 Planetary gear mechanism (reduction mechanism)
42 Housing 44 Shaft support 45 Recessed groove 46 Nut member 47 Tapered surface 48 Pin hole 50 Non-rotating pin 50A Lower surface 51 Fitting hole

Claims (5)

A housing which is arranged in the vertical direction with the upper side serving as a speed reduction mechanism housing portion and the lower side serving as a shaft support portion, a speed reduction mechanism provided in the speed reduction mechanism housing portion of the housing and decelerating rotation of a rotation source, and a shaft support of the housing An output shaft that is inserted through the shaft and outputs rotation decelerated by the speed reduction mechanism, a bearing that is provided on the shaft support portion of the housing and rotatably supports the output shaft, and is positioned above the bearing. A reduction device comprising a nut member provided on an outer peripheral side of the output shaft and positioning the bearing with the shaft support portion of the housing;
In order to prevent foreign matter mixed in the lubricating oil that lubricates the speed reduction mechanism in the housing from entering the bearing, the outer diameter of the nut member is set to be equal to or larger than the diameter of the outer ring constituting the bearing. A speed reducer characterized by that. The speed reducer according to claim 1, wherein a tapered surface whose outer peripheral side is gradually inclined downward is provided on an upper surface of the nut member. The speed reduction according to claim 1 or 2, wherein the shaft support portion of the housing is provided with an annular recessed groove located on the outer peripheral side of the bearing to capture foreign matter scattered from the outer peripheral side of the nut member. apparatus. A locking pin inserted into a pin hole provided in the nut member is provided on the lower surface of the carrier of the speed reduction mechanism that meshes with the rotating shaft, and at least a part of the lower surface of the locking pin constitutes the inner ring constituting the bearing. The speed reducer according to claim 1, 2, or 3, wherein the speed reducer is configured to face the upper surface. 5. The nut member according to claim 1, 2, 3 or 4, wherein the nut member is provided with a plurality of pin holes on a circumference having a constant radius, and the locking pin is inserted into any one of the pin holes. The speed reducer described.

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