CN111033081A - Speed reducer - Google Patents

Abstract

The invention provides a speed reducer capable of stably supplying lubricating oil to a spline joint part of a rotation source and a rotation shaft even if a rotation side shell rotates at a high speed for a long time. A reduction gear (14) is provided with a multi-stage planetary gear mechanism (23, 31, 37) that reduces the rotation of a hydraulic motor (12) and transmits the rotation to a rotation-side housing (17), wherein an output shaft (13) of the hydraulic motor (12) and a rotation shaft (24) are coupled by a spline coupling section (S), and the rotation-side housing (17) is filled with lubricating oil (43). A third carrier (40) of a final-stage planetary gear mechanism (37) is fixedly supported by a fixed-side housing (15), and a supply path (44) is formed by a through hole (45) formed in the third carrier (40) and a space (46) present above a spline joint (S), so that lubricating oil (43) discharged from a meshing portion between a third sun gear (38) and a third planetary gear (39) is supplied to the spline joint (S) through the through hole (45) and the space (46) even during high-speed and long-time traveling.

Description

Speed reducer

Technical Field

The present invention relates to a reduction gear suitable for use in, for example, a traveling device of a hydraulic excavator or a hydraulic crane.

Background

In general, a rail vehicle such as a hydraulic excavator includes: a traveling body capable of traveling by itself through a traveling device; an upper revolving structure rotatably mounted on the traveling structure; and a working device provided on the front side of the upper slewing body so as to be capable of pitching motion.

The traveling device includes: a fixed-side case fixed to one of front and rear side frames fixed to left and right sides of a frame of the traveling body; a rotation source mounted to the fixed-side case; a rotating-side housing rotatably supported by the fixed-side housing and having a sprocket attached thereto, the sprocket engaging with a track for running; a rotating shaft inserted between the rotating source and the rotating-side housing in the axial direction of the fixed-side housing; and a planetary gear mechanism that decelerates rotation of the rotating shaft and transmits the rotation to the rotating-side housing.

As a conventional technique of the traveling apparatus configured as described above, a technique using a reduction gear as follows is known: as described in patent document 1, a large reduction ratio can be obtained by providing the planetary gear mechanism with a plurality of stages, for example, three stages.

Specifically, in the reduction gear device described in patent document 1, the first-stage planetary gear mechanism includes: a rotating shaft spline-coupled at one end side to an output shaft of the rotation source; a first sun gear provided on the other end side of the rotating shaft; a first planetary gear which is disposed so as to mesh with the first sun gear and an internal gear provided on an inner peripheral side of the rotation-side housing, and which revolves around the first sun gear while rotating on its axis; and a first carrier rotatably supporting the first planetary gear. Further, the second-stage planetary gear mechanism includes: a second sun gear loosely fitted to the rotation shaft and transmitting revolution of the first carrier; a second planetary gear disposed so as to mesh with the second sun gear and the internal gear of the rotation-side housing, and revolving around the second sun gear while rotating on its axis; and a second carrier rotatably supporting the second planetary gear. The third-stage (final-stage) planetary gear mechanism includes: a third sun gear loosely fitted to the rotation shaft and transmitting revolution of the second carrier; a third planetary gear disposed so as to mesh with the third sun gear and the internal gear of the rotation-side housing, and rotating around the second sun gear; and a third carrier rotatably supporting the third planetary gear, the third carrier being mounted to the fixed-side case in a non-rotating state.

In the reduction gear device configured as described above, when the motor as the rotation source rotates, the rotation is reduced at a predetermined reduction ratio by the first-stage planetary gear mechanism composed of the first sun gear, the first planetary gear, the first carrier, and the like, and only the revolution of the first planetary gear is output from the first carrier to the second sun gear of the second-stage planetary gear mechanism. Further, the second-stage planetary gear mechanism constituted by the second sun gear, the second planetary gear, the second carrier, and the like further decelerates the rotation from the first carrier at a predetermined reduction ratio, and outputs only the revolution of the second planetary gear from the second carrier to the third sun gear of the final-stage planetary gear mechanism. In addition, since the third carrier is attached to the stationary-side housing in a non-rotating state, the planetary gear mechanism of the final stage including the third sun gear, the third planetary gear, the third carrier, and the like can reduce the rotational output from the second carrier at a predetermined reduction ratio and transmit the reduced rotational output from the third sun gear to the rotating-side housing via the third planetary gear, thereby generating a large rotational torque in the rotating-side housing.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 10-159914

Disclosure of Invention

Problems to be solved by the invention

However, in the conventional traveling device, the inside of the rotation-side housing is usually filled with lubricating oil for lubricating the planetary gear mechanism, and the lubricating oil is filled up to a position passing through the central axis of the sun gear of the planetary gear mechanism. Here, if the vehicle is stopped or traveling at a low speed for a short time, the oil level of the lubricating oil is less stirred and scattered by the rotation of the planetary gear mechanism, and therefore the lower portion of the spline coupling portion between the output shaft of the motor as the rotation center and the rotating shaft is continuously immersed in the lubricating oil.

However, during high-speed and long-time running of the vehicle, the lubricating oil sticks to the ring gear of the rotation-side housing due to the action of viscosity or centrifugal force, and the oil level of the lubricating oil drops as a result, so that the spline joint portion between the output shaft of the motor and the rotation shaft may be completely exposed from the oil level of the lubricating oil. If this state continues, the lubricating oil supplied to the spline joint between the output shaft of the motor and the rotating shaft becomes insufficient, and a problem occurs in that the life of the spline joint decreases. Further, if the amount of filling of the lubricating oil is increased to such an extent that a sufficient oil level height can be secured even when the oil level is lowered, the lubricating oil can be supplied to the spline joint portion even when the oil level is lowered, but in this case, since the stirring resistance of the lubricating oil increases, another problem occurs such that the running efficiency is lowered, and a problem also occurs in that the cost of the lubricating oil increases.

The present invention has been made in view of the above circumstances of the prior art, and an object of the present invention is to provide a reduction gear device capable of stably supplying lubricating oil to a spline joint portion between a rotation source and a rotating shaft even when a rotating-side housing is rotated at a high speed for a long time without increasing the amount of lubricating oil to be filled.

Means for solving the problems

In order to achieve the above object, a reduction gear according to the present invention includes: a fixed-side housing; a rotation source provided in the fixed-side housing; a rotating-side housing rotatably supported by the fixed-side housing; a rotating shaft having one end spline-coupled to the rotation source and the other end supported by the rotation-side housing; and a multi-stage planetary gear mechanism that reduces the rotation of the rotating shaft and transmits the rotation to the rotating-side housing, wherein a lubricant oil is filled in the rotating-side housing, wherein a carrier of the final-stage planetary gear mechanism is fixedly supported by the fixed-side housing, and the carrier is provided with a supply path that faces a meshing portion between a sun gear and a planetary gear of the final-stage planetary gear mechanism, and wherein the lubricant oil adhering to the meshing portion between the sun gear and the planetary gear is supplied to a spline joint portion between the rotating source and the rotating shaft through the supply path in accordance with the rotation of the rotating source.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the reduction gear of the present invention, even if the rotation-side housing rotates at a high speed for a long time, the lubricating oil can be stably supplied to the spline-coupled portion between the rotation source and the rotation shaft. Problems, structures, and effects other than those described above will be more apparent from the following description of the embodiments.

Drawings

Fig. 1 is a front view showing a hydraulic excavator provided with a reduction gear unit according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view of the running gear disposed in the running body as viewed from the direction of arrow II-II in fig. 1.

Fig. 3 is an enlarged view of a main portion of the running gear shown in fig. 2.

Fig. 4 is a sectional view showing a main part of a reduction gear transmission according to a first embodiment of the present invention.

Fig. 5 is an explanatory view as viewed from the direction of arrow a in fig. 4.

Fig. 6 is a cross-sectional view of a travel device including a reduction gear unit according to a second embodiment of the present invention.

Fig. 7 is a cross-sectional view of a travel device including a reduction gear transmission according to a third embodiment of the present invention.

Fig. 8 is a cross-sectional view of a travel device including a reduction gear transmission according to a fourth embodiment of the present invention.

Fig. 9 is a cross-sectional view of a travel device including a reduction gear transmission according to a fifth embodiment of the present invention.

Fig. 10 is an explanatory view of a final stage carrier provided in the reduction gear of fig. 9, as viewed from the hydraulic motor side.

Fig. 11 is a cross-sectional view of a travel device including a reduction gear transmission according to a sixth embodiment of the present invention.

Detailed Description

Hereinafter, an embodiment of the reduction gear transmission according to the present invention will be described in detail by taking a case of being applied to a traveling device of a hydraulic excavator as an example with reference to the drawings.

First, the structure of the hydraulic excavator will be explained. Fig. 1 is a front view of a hydraulic excavator as a typical example of a construction machine, and the hydraulic excavator 1 generally includes: a self-propelled rail-type (crawler-type) traveling body 2; an upper revolving structure 3 rotatably mounted on the traveling structure 2; and a working mechanism 4 provided at the front side of the upper slewing body 3 so as to be capable of tilting, and excavation work or the like is performed using the working mechanism 4.

The traveling body 2 includes a frame 5 serving as a base, and the frame 5 includes left and right side frames 5A (only the left side is shown) extending in the front-rear direction. A floating wheel 6 is provided on one end side in the longitudinal direction of each side frame 5A, and a traveling device 9 described later is provided on the other end side in the longitudinal direction of each side frame 5A. A Crawler belt (Crawler)8 in a ring shape is wound around the driving wheel (sprocket) 7 and the loose wheel 6 of the traveling device 9.

Fig. 2 is a sectional view of the running gear 9 as seen from the direction of the arrow II-II in fig. 1, and fig. 3 is an enlarged view of a main portion of the running gear 9 shown in fig. 2.

As shown in fig. 2 and 3, the traveling device 9 is configured by a hydraulic motor 12, a reduction gear 14, a fixed-side case 15, a rotating-side case 17, a rotating shaft 24, and the like, and the reduction gear 14 includes a multi-stage, for example, three-stage planetary gear mechanism 23, 31, 37, and the like, which will be described later. The traveling device 9 rotates the driving wheels 7 with a large torque by decelerating the rotation of the hydraulic motor 12 by the reduction gear 14, and drives the crawler belt 8 wound around between the driving wheels 7 and the loose wheels 6 to rotate.

The hydraulic motor 12 as a rotation source rotates and drives a cylindrical output shaft 13 by supplying pressure oil from a hydraulic pump (not shown). A hole-side spline portion 13A is provided on the inner peripheral surface of the output shaft 13, and the hole-side spline portion 13A is spline-coupled to a shaft-side spline portion 24A (described later) of the rotary shaft 24 (see fig. 3).

The fixed-side casing 15 has a cylindrical portion 15A, a bottom portion 15B, and a lid portion 15C, and houses the hydraulic motor 12 therein. An annular flange portion 15D is integrally formed on the outer peripheral side of the cylindrical portion 15A, and the flange portion 15D is fastened to the side frame 5A with bolts or the like. An axial spline portion 15E is provided on the outer peripheral side of the cylindrical portion 15A, and the axial spline portion 15E is spline-coupled to a hole-side spline portion 40B of the final-stage third carrier 40, which will be described later. An output shaft 13 is rotatably provided at the center of the bottom portion 15B, and the output of the hydraulic motor 12 is transmitted from the output shaft 13 to the rotary shaft 24.

The rotation-side housing 17 roughly includes: a drum main body 10 located on an outer peripheral side of the fixed-side case 15; a drum 11 having an internal gear 11A on an inner peripheral side; and a bottom cover 16 covering the drum 11.

The drum body 10 is rotatably supported by the cylindrical portion 15A of the fixed-side case 15 via a main bearing 50, and the main bearing 50 is axially positioned by a bearing nut 25 attached to the distal end side of the fixed-side case 15. A mechanical seal (floating seal) 20 is provided outside the main bearing 50, and a lubricating oil 43 described later filled in the rotation-side housing 17 is sealed by the mechanical seal 20. An annular flange portion 10A is integrally formed on the outer peripheral side of the drum body 10, and a drive wheel (sprocket) 7 that meshes with the crawler 8 is fastened to the flange portion 10A with a bolt 18. As shown in fig. 2, the length of the traveling device 9 in the axial direction is set to be shorter than the width of the crawler 8, and the entire traveling device 9 fits within the width of the crawler 8.

The drum 11 is fastened to the drum body 10 by bolts 19, and an internal gear 11A meshing with first to third planetary gears 27, 33, and 39 described later is provided on the inner peripheral side of the drum 11.

The bottom cover 16 is fastened to the open end of the drum 11 by a bolt 21, and a liner 22 located at the axial center and in sliding contact with the front end surface of a first sun gear 26 described later is fitted to the inside of the bottom cover 16.

The reduction gear 14 reduces the rotation of the hydraulic motor 12 and transmits the rotation to the rotating-side housing 17, and is configured by a fixed-side housing 15, the rotating-side housing 17, a first-stage planetary gear mechanism 23, a second-stage planetary gear mechanism 31, a third-stage (final-stage) planetary gear mechanism 37, and the like.

The first-stage planetary gear mechanism 23 reduces the speed of rotation of the hydraulic motor 12 and transmits the rotation to the second-stage planetary gear mechanism 31, and is configured by a rotating shaft 24, a first sun gear 26, first planetary gears 27, a first carrier 28, and the like.

A shaft-side spline portion 24A is provided on the base end side of the rotary shaft 24, and as described above, the shaft-side spline portion 24A is spline-coupled to the hole-side spline portion 13A provided on the output shaft 13 of the hydraulic motor 12. That is, the rotary shaft 24 is disposed coaxially with the output shaft 13 of the hydraulic motor 12, and rotates integrally with the output shaft 13 of the hydraulic motor 12.

The first sun gear 26 is provided on the front end side of the rotary shaft 24, and the first planetary gears 27 mesh with the first sun gear 26 and the internal gear 11A provided on the inner peripheral side of the drum 11. The first planetary gears 27 revolve around the first sun gear 26 while rotating on its axis, and for example, three (only one shown) are provided around the first sun gear 26.

The first carrier 28 is a disk-shaped member having a smaller diameter than the diameter of the tooth point circle of the internal gear 11A, and has a shaft insertion hole through which the rotary shaft 24 is inserted in the center portion thereof. The first carrier 28 rotatably supports the first planetary gears 27 via bearings 29 and pins 30, and the first planetary gears 27 revolve around the first sun gear 26 while rotating on their own axis, and the revolution is transmitted to the second sun gear 32 of the next-stage planetary gear mechanism 31.

The second-stage planetary gear mechanism 31 transmits the rotation of the first-stage planetary gear mechanism 23 to the third-stage planetary gear mechanism 37 while reducing the speed, and is configured by the second sun gear 32, the second planetary gears 33, the second carrier 34, and the like.

The second sun gear 32 has a shaft insertion hole in the center portion through which the rotating shaft 24 is inserted, and the second sun gear 32 is spline-coupled to the first stage first carrier 28. A plurality of second planetary gears 33 (only one is shown) are disposed so as to mesh with the second sun gear 32 and the internal gear 11A, and revolve around the second sun gear 32 while rotating on its axis.

The second carrier 34 is a disk-shaped member having a diameter smaller than the diameter of the tooth tip circle of the internal gear 11A, and has a shaft insertion hole through which the rotary shaft 24 is inserted in the center portion thereof. The second carrier 34 rotatably supports each second planetary gear 33 via a bearing 35 and a pin 36, and each second planetary gear 33 revolves around the second sun gear 32 while rotating on its axis, and the revolution is transmitted to the third sun gear 38 of the final stage planetary gear mechanism 37.

The final-stage (third-stage) planetary gear mechanism 37 decelerates the rotation of the second-stage planetary gear mechanism 31 and transmits it to the drum 11 of the rotating-side housing 17, and is constituted by a third sun gear 38, a third planetary gear 39, a third carrier 40, and the like.

The third sun gear 38 has a shaft insertion hole in the center portion through which the rotating shaft 24 is inserted, and the third sun gear 38 is spline-coupled to the second stage second carrier 34. The third planetary gears 39 mesh with the third sun gear 38 and the ring gear 11A, and a plurality of, for example, three (only one shown) are arranged so as to rotate around the third sun gear 38.

The third carrier 40 is a disk-shaped member having a smaller diameter than the diameter of the tooth point circle of the internal gear 11A, and has a shaft insertion hole through which the rotary shaft 24 is inserted in the center portion thereof. The third carrier 40 rotatably supports each third planetary gear 39 via a bearing 41 and a pin 42, and a hole-side spline portion 40B is formed on an inner surface of an annular projection 40A that projects from one end surface of the third carrier 40 toward the hydraulic motor 12 side. The hole-side spline portion 40B is spline-coupled to the shaft-side spline portion 15E of the fixed-side case 15, whereby the third carrier 40 is non-rotatably mounted on the fixed-side case 15.

Thus, when the hydraulic motor 12 is operated and the output shaft 13 rotates, the rotation of the output shaft 13 is reduced at a predetermined reduction ratio by the first-stage planetary gear mechanism 23 including the rotary shaft 24, the sun gear 26, the first planetary gears 27, the first carrier 28, and the like, and only the revolution of the first planetary gears 27 is output from the first carrier 28 to the second sun gear 32 of the second-stage planetary gear mechanism 31.

Then, the second-stage planetary gear mechanism 31, which is composed of the second sun gear 32, the second planetary gears 33, the second carrier 34, and the like, further decelerates the rotation from the first carrier 28 at a predetermined reduction ratio, and outputs only the revolution of the second planetary gears 33 from the second carrier 34 to the third sun gear 38 of the final-stage (third-stage) planetary gear mechanism 37.

Also, in the final-stage planetary gear mechanism 37 constituted by the third sun gear 38, the third planetary gears 39, the third carrier 40, and the like, the third carrier 40 is mounted to the fixed-side case 15 in a non-rotating state, and therefore the rotational output from the second carrier 34 is reduced in speed at a predetermined reduction ratio and transmitted from the third sun gear 38 to the drum 11 via the third planetary gears 39. As a result, the rotation side housing 17 including the drum 11, the drum body 10, the bottom cover 16, and the like rotates with a large torque, and the crawler 8 wound around the loose wheels 6 and the driving wheels 7 is driven to rotate, whereby the hydraulic excavator 1 travels.

In the traveling apparatus 9 configured as described above, the lubricating oil 43 for smoothly driving the gears of the first to third planetary gear mechanisms 23, 31, and 37 is filled in the rotating-side housing 17, and the lubricating oil 43 is filled in the vicinity of a horizontal plane passing through the center axis (line P shown in fig. 3) of the rotating shaft 24.

Here, if the vehicle (the traveling structure 2) is stopped or traveling at a low speed for a short time, the oil level of the lubricating oil 43 is less stirred or scattered by the rotation of each planetary gear mechanism 23, 31, 37, and therefore the lower portion of the spline coupling portion S (the coupling portion between the hole-side spline portion 13A and the shaft-side spline portion 24A) between the output shaft 13 of the hydraulic motor 12 and the rotating shaft 24 is continuously immersed in the lubricating oil 43. However, during high-speed, long-time running of the vehicle, the lubricating oil 43 sticks to the internal gear 11A of the drum 11 due to the action of viscosity or centrifugal force, and the oil surface of the lubricating oil 43 is lowered in association therewith, so that the spline joint portion between the output shaft 13 of the hydraulic motor 12 and the rotary shaft 24 may be completely exposed from the oil surface of the lubricating oil 43.

In order to solve such a problem, in the reduction gear 14 according to the first embodiment of the present invention, a supply path 44 facing a meshing portion between the third sun gear 38 and the third planetary gear 39 is provided in the third carrier 40 of the final-stage planetary gear mechanism 37. The supply path 44 will be described in detail below with reference to fig. 4 and 5.

Fig. 4 is a cross-sectional view showing a main part of the reduction gear transmission 14 according to the first embodiment provided in the traveling device 9, and fig. 5 is an explanatory view seen from the direction of arrow a in fig. 4.

In the reduction gear 14 of the first embodiment, the through hole 45 is formed in the third carrier 40 of the final stage, and the through hole 45 is communicated with the space 46 existing between the cylindrical portion 15A of the fixed-side housing 15 and the third carrier 40, whereby the supply path 44 is formed by the through hole 45 and the space 46 (see fig. 3).

As shown in fig. 5, the through hole 45 is formed in an elongated hole shape so as to face the meshing portion of the third sun gear 38 and the third planetary gear 39, and the through hole 45 is located above the oil surface of the lubricating oil 43 filled in the rotation-side housing 17. Space 46 is located around spline coupling portion S where hole-side spline portion 13A of output shaft 13 and shaft-side spline portion 24A of rotary shaft 24 are coupled, and through hole 45 communicates with space 46 present above spline coupling portion S. That is, the inlet of the supply path 44 is located at the meshing portion of the third sun gear 38 and the third planetary gear 39, and the outlet of the supply path 44 is located above the spline-coupling portion S of the output shaft 13 and the rotary shaft 24.

In the reduction gear unit 14 having the supply path 44, when the hydraulic motor 12 rotates, the third planetary gears 39 meshing with the third sun gear 38 rotate while meshing with the ring gear 11A, and the lubricating oil 43 adhering to the surface of the meshing portion between the third sun gear 38 and the third planetary gears 39 is discharged in the axial direction. The lubricating oil 43 enters the space 46 from the through hole 45 that is the inlet of the supply path 44, and is supplied to the spline coupling portion S from the lower end of the space 46 that is the outlet of the supply path 44. Therefore, even when the vehicle is traveling at high speed for a long period of time, the lubricating oil 43 discharged from the meshing portion between the third sun gear 38 and the third planetary gear 39 is supplied to the spline joint S between the bore-side spline portion 13A of the output shaft 13 and the shaft-side spline portion 24A of the rotary shaft 24, and the life of the spline joint S can be suppressed from decreasing.

As described above, in the reduction gear 14 of the first embodiment, the third carrier 40, which is a component of the final-stage planetary gear mechanism 37, is fixedly supported by the fixed-side case 15, the through hole 45 that faces the meshing portion of the third sun gear 38 and the third planetary gear 39 is provided in the third carrier 40, and the through hole 45 is made to communicate with the space portion 46 located above the spline coupling portion S, so that the lubricating oil 43 discharged from the meshing portion of the third sun gear 38 and the third planetary gear 39 can be supplied to the spline coupling portion S even if the oil level of the lubricating oil 43 drops during high-speed, long-time traveling of the vehicle. Therefore, even if the filling amount of the lubricating oil 43 is not increased, the lubricating oil 43 can be supplied to the spline joint S during high-speed and long-time running, and a reduction in the life of the spline joint S can be suppressed without causing problems such as a reduction in running efficiency and an increase in the cost of the lubricating oil 43.

Fig. 6 is a cross-sectional view of a travel device including a reduction gear unit according to a second embodiment, and parts corresponding to fig. 2 and 3 are denoted by the same reference numerals.

In the reduction gear 14 of the second embodiment shown in fig. 6, the depth dimension D (the length in the axial direction of the fixed-side case 15) of the space portion 46 communicating with the through hole 45 is made narrower than that of the first embodiment, and the lower end of the space portion 46 is opposed to the position of the output shaft 13 slightly shifted from the tip end provided with the hole-side spline portion 13A toward the other end side in the axial direction. That is, the lower end of space 46, which is the outlet of supply path 44, is positioned directly above shaft-side spline 24A of rotary shaft 24 exposed from spline joint S. The other structure is basically the same as that of the first embodiment.

In the reduction gear 14 of the second embodiment configured as described above, the lubricating oil 43 discharged from the meshing portion between the third sun gear 38 and the third planetary gear 39 is supplied from the through hole 45 to the shaft-side spline portion 24A of the rotating shaft 24 through the space portion 46 accurately and efficiently, and therefore the lubricating oil 43 is introduced into the hole-side spline portion 13A and the shaft-side spline portion 24A that are joined at the spline joint portion S, and the reduction in the life of the spline joint portion S can be suppressed.

Fig. 7 is a cross-sectional view of a travel device including a reduction gear unit according to a third embodiment, and parts corresponding to fig. 2 and 3 are denoted by the same reference numerals.

In the reduction gear 14 of the third embodiment shown in fig. 7, a tapered through hole 47 is formed in the third carrier 40, and the through hole 47 and the space 46 constitute the supply path 44. The through hole 47 is a tapered through hole having a reduced opening diameter on the outlet side facing the space portion 46 with respect to the opening diameter on the inlet side facing the meshing portion of the third sun gear 38 and the third planetary gear 39. The other structure is basically the same as that of the first embodiment.

In the reduction gear unit 14 of the third embodiment configured as described above, the lubricating oil 43 discharged from the meshing portion between the third sun gear 38 and the third planetary gear 39 is supplied from the through hole 47 to the spline coupling portion S through the space portion 46, but at this time, since the through hole 47 is tapered to reduce the opening diameter on the outlet side, the lubricating oil 43 discharged from the meshing portion can be collected in the tapered through hole 47 and efficiently sent to the space portion 46. This enables the lubricating oil 43 to be supplied to the spline joint S between the output shaft 13 and the rotary shaft 24 even during high-speed and long-time traveling, and thus, the life of the spline joint S can be prevented from decreasing.

Fig. 8 is a cross-sectional view of a travel device including a reduction gear transmission according to a fourth embodiment, and parts corresponding to fig. 2 and 3 are denoted by the same reference numerals.

In the reduction gear 14 of the fourth embodiment shown in fig. 8, the inclined hole 48 is formed in the third carrier 40, and the supply path 44 is formed by the inclined hole 48. The inclined hole 48 is provided inside the bulge portion 40C projecting from the end surface of the third carrier 40, and the bulge portion 40C enters the lower end side of the space portion 46. One end side of the inclined hole 48 faces the meshing portion of the third sun gear 38 and the third planetary gear 39, the other end side of the inclined hole 48 faces the vicinity of the spline coupling portion S, and the inclined hole 48 is inclined at a descending slope from the opening portion on the one end (inlet) side toward the opening portion on the other end (outlet) side. The other structure is basically the same as that of the first embodiment.

In the reduction gear unit 14 of the fourth embodiment configured as described above, the lubricating oil 43 discharged from the meshing portion between the third sun gear 38 and the third planetary gear 39 passes through the inside of the inclined hole 48 in an obliquely downward direction and is supplied to the spline joint portion S, so that a reduction in the life of the spline joint portion S can be suppressed even during high-speed and long-time traveling.

Fig. 9 is a cross-sectional view of a travel device including a reduction gear transmission according to a fifth embodiment, and fig. 10 is an explanatory view of a final stage carrier provided in the reduction gear transmission as viewed from a hydraulic motor side, and parts corresponding to fig. 2 and 3 are given the same reference numerals.

In the reduction gear 14 of the fifth embodiment shown in fig. 9, the slit 49 is provided in the third carrier 40 instead of the through hole 45, and the slit 49 and the space 46 constitute the supply path 44. As shown in fig. 10, the upper end side of the slit 49 is located at a position facing the meshing portion of the third sun gear 38 and the third planetary gears 39, and the lower end side of the slit 49 reaches the outer peripheral edge of the shaft insertion hole 40D provided at the central portion of the third carrier 40. The slit 49 can be easily formed in the third carrier 40 by cutting or the like, and the ejection flow rate of the lubricating oil 43 can be easily controlled by adjusting the slit width W of the slit 49. The other structure is basically the same as that of the first embodiment.

In the reduction gear unit 14 of the fifth embodiment configured as described above, the lubricating oil 43 discharged from the meshing portion between the third sun gear 38 and the third planetary gear 39 is supplied from the slit 49 to the spline joint portion S through the space portion 46, and therefore, the reduction in the life of the spline joint portion S can be suppressed even during high-speed and long-time traveling.

Fig. 11 is a cross-sectional view of a travel device including a reduction gear transmission according to a sixth embodiment, and parts corresponding to fig. 2 and 3 are denoted by the same reference numerals.

In the reduction gear 14 of the sixth embodiment shown in fig. 11, in order to screw the bearing nut 25 to the tip end side of the fixed-side case 15 and to realize the rotation stop of the bearing nut 25, the bearing nut 25 is fixed to the inner ring of the main bearing 50 using the screw member 51. The screw member 51 is not coupled to the third carrier 40, and the third carrier 40 is non-rotatably mounted to the fixed-side case 15 by spline-coupling the hole-side spline portion 40B and the shaft-side spline portion 15E. The other structure is basically the same as that of the first embodiment.

In the reduction gear transmission 14 of the sixth embodiment configured as above, since the rotation of the bearing nut 25 is stopped by using the screw member 51 independent of the third carrier 40, the through hole 45 serving as the inlet of the supply path can be easily set to an optimum position above the oil surface of the lubricating oil 43 regardless of the mounting position of the screw member 51.

In addition, although the above embodiments have described the case where the rotation of the hydraulic motor 12 is decelerated by the first to third planetary gear mechanisms 23, 31, and 37 and transmitted to the rotation-side housing 17, the number of planetary gear mechanisms used is not limited to three stages as long as the number is 2 or more.

The above embodiments are illustrative of the present invention, and the scope of the present invention is not limited to these embodiments. Those skilled in the art can implement the present invention in other various ways without departing from the scope of the present invention.

Description of the symbols

1-a hydraulic excavator, 2-a traveling body, 3-an upper slewing body, 4-a working device, 5-a frame, 6-a loose wheel, 7-a driving wheel, 8-a crawler, 9-a traveling device, 10-a drum body, 11-a drum, 11A-an internal gear, 12-a hydraulic motor (a rotation source), 13-an output shaft, 13A-a hole-side spline portion, 14-a reduction gear, 15-a fixed-side housing, 15A-a cylindrical portion, 16-a bottom cover, 17-a rotation-side housing, 23-a first-stage planetary gear mechanism, 24-a rotation shaft, 24A shaft-side spline portion, 25-a bearing nut, 26-a first sun gear, 27-a first planetary gear, 28-a first carrier, 31-a second-stage planetary gear mechanism, 32-a second sun gear, 33-a second planetary gear, 34-a second carrier, 37-a third-stage planetary gear mechanism, 38-a third sun gear, 39-third planetary gear, 40-third carrier (final stage carrier), 40C-bulging portion, 40D-shaft insertion hole, 43-lubricating oil, 44-supply path, 45-through hole, 46-space portion, 47-through hole, 48-inclined hole (supply path), 49-slit, 50-main bearing, 51-screw member, S-spline joint portion.

Claims (9)

1. A reduction gear device is provided with: a fixed-side housing; a rotation source provided in the fixed-side housing; a rotating-side housing rotatably supported by the fixed-side housing; a rotating shaft having one end spline-coupled to the rotation source and the other end supported by the rotation-side housing; and a multi-stage planetary gear mechanism for transmitting the rotation of the rotating shaft to the rotating-side housing while reducing the speed of the rotation of the rotating shaft, wherein the rotating-side housing is filled with a lubricating oil,

the carrier of the planetary gear mechanism of the final stage is fixedly supported by the fixed-side housing, and the carrier is provided with a supply path facing a meshing portion between a sun gear and a planetary gear of the planetary gear mechanism of the final stage, and the lubricating oil adhering to the meshing portion between the sun gear and the planetary gear is supplied to a spline joint portion between the rotation source and the rotation shaft through the supply path in accordance with rotation of the rotation source.

2. Deceleration device according to claim 1,

an outlet on a lower end side of the supply path is opposed to a position shifted toward the other end side of the rotary shaft with respect to the spline coupling portion.

3. Deceleration device according to claim 1,

the supply path has a through hole formed through the carrier, and an opening on the rotation source side of the through hole is set at a position lower than at least the same height with respect to an opening on the engagement portion side.

4. Deceleration device according to claim 3,

the through hole is a tapered hole having an opening diameter on the rotation source side reduced with respect to an opening diameter on the engagement portion side.

5. Deceleration device according to claim 1,

the supply path has an inclined hole formed through the carrier,

the inclined hole is inclined at a downward inclination from the opening on the engagement portion side toward the opening on the rotation source side.

6. Deceleration device according to claim 1,

the carrier is provided with an insertion hole through which the rotary shaft is inserted, and the supply path has a slit reaching an outer peripheral edge of the insertion hole.

7. Deceleration device according to claim 2,

the supply path has a through hole formed through the carrier, and an opening on the rotation source side of the through hole is set at a position lower than at least the same height with respect to an opening on the engagement portion side.

8. Deceleration device according to claim 7,

the through hole is a tapered hole having an opening diameter on the rotation source side reduced with respect to an opening diameter on the engagement portion side.

9. Deceleration device according to claim 2,

the supply path has an inclined hole formed through the carrier,

the inclined hole is inclined at a downward inclination from the opening on the engagement portion side toward the opening on the rotation source side.

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