JP2010144870A - Swing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a swing device keeping down pressure in a grease chamber with a second bearing arranged therein. <P>SOLUTION: The swing device includes a first bearing 20 supporting an upper part of an output shaft 17 and supplied with gear oil, the second bearing 21 supporting a lower part of the output shaft 17 and supplied with grease, a housing 14 forming the outer shell of a bearing housing, an oil seal 22 sealing between the first bearing 20 and the second bearing 21, an annular cutout part 23 formed in a lower end of the housing 14, a plate 24 forming a first gap 46 between the plate and a lower end of the housing 14, and a dust seal 26 received in an annular recess 25 formed by the plate 24 and the cutout part 23, and a space in which the second bearing 21 of the housing 14 is arranged forms the grease chamber 30. An air passage capable of releasing the pressure of the grease chamber 30, for instance, a groove 45, is formed on an upper wall surface of the cutout part 23 of the housing 14 facing the upper surface of the dust seal 26. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is provided in a work machine such as a hydraulic excavator, and includes a turning motor for turning a turning body, a planetary reduction mechanism connected to the turning motor, and an output shaft that is provided integrally with the planetary reduction mechanism. The present invention relates to a swivel device having a bearing box.

  FIG. 3 is a side view showing a hydraulic excavator exemplified as an example of a working machine provided with a turning device. This hydraulic excavator includes a traveling body 1, a revolving body 3 disposed on the traveling body 1 via a revolving wheel 2, and a front work machine 5 attached to the revolving body 3 so as to be rotatable in the vertical direction. I have. The front work machine 5 includes a boom 6 that is rotatably attached to the swing body 3, an arm 7 that is rotatably attached to the tip of the boom 6, and a bucket 8 that is rotatably attached to the tip of the arm 7. Including. A turning device 4 for turning the turning body 3 is provided so as to be interposed between the traveling body 1 and the turning body 3.

  FIG. 4 is a front view showing a part of a conventional turning device, and FIG. 5 is a longitudinal sectional view showing an enlarged main part of FIG.

  As shown in FIG. 4, the conventional turning device 4 includes a turning motor 10, a planetary speed reducing mechanism 11 that decelerates and increases the torque of the turning motor 10, and an output that transmits the torque of the planetary speed reducing mechanism 11. And a bearing box 12 in which the shaft 17 is accommodated. The carrier 13 of the swivel reducer 11 and the housing 14 that forms the outer shell of the bearing housing 12 are fixed by bolts 15. The housing 14 is fixed to the revolving unit 3 by bolts 16. The tooth portion 18 of the output shaft 17 of the turning device 4 meshes with the inner ring 2 a of the turning wheel 2 fixed to the traveling body 1. The outer ring 2 b of the turning wheel 2 is fixed to the turning body 3. The traveling body 1 is provided with a grease bath 19 in which grease for lubricating a meshing portion between the tooth portion 18 of the output shaft 17 and the inner ring 2a of the turning wheel 2 is accommodated.

  In the housing 14 of the bearing box 12, a first bearing 20 that supports the upper portion of the output shaft 17 and is supplied with gear oil, and a second bearing 21 that supports the lower portion of the output shaft 17 and is supplied with grease. Is provided. The first bearing 20 and the second bearing 21 are tapered roller bearings that are fixed by the pressing force of the nut 27. In addition, an oil seal 22 is provided that is mounted on the housing 14 and seals between the first bearing 20 and the second bearing 21.

  Further, as shown in FIG. 5, the housing 14 is accommodated in an annular recess 25 formed at the lower end portion of the housing 14 and formed by an annular notch 23 having a lateral opening and a plate 24. A dust seal 26 is provided to prevent foreign matter and dust from entering the device. The dust seal 26 is made of, for example, urethane rubber.

  A space portion in which the second bearing 21 of the housing 14 is disposed communicates with the oil seal 22 to form a grease chamber 30 in which grease for lubricating the second bearing 21 is accommodated. The output shaft 17 extends along the axial center of the output shaft 17 and extends in the radial direction of the output shaft 17. The first supply pipe 31 guides grease for lubricating the second bearing 21. A second supply line 32 that communicates with the first supply line 31 and communicates with the grease chamber 30 at the other end is formed. A grease nipple 33 is attached to the lower end portion of the first supply conduit 31.

There exists a thing shown by patent document 1 as this kind of well-known technique. In this Patent Document 1, the side of the annular recess in which the dust seal is accommodated is not opened, but the first bearing disposed in the housing and supporting the upper portion of the output shaft, and the lower portion of the output shaft The 2nd bearing to support, the oil seal which seals between these 1st bearings and a 2nd bearing, the plate etc. which hold | maintain the lower end part of the above-mentioned dust seal are indicated.
German Patent Application Publication No. 196 03 007

  FIG. 6 is a longitudinal sectional view of a main part for explaining the problems of the conventional turning device. As shown in FIG. 6, an internal pressure is generated in the grease chamber 30 as the grease is supplied. Further, as the ratio of the air in the grease chamber 30 to the supply amount of grease is smaller, a higher internal pressure is generated in the grease chamber 30 due to the temperature rise during the operation of the swivel device 4. Therefore, in the prior art, due to the high pressure generated in the grease chamber 30, the oil seal 22 is high in the direction indicated by the arrow 40 in FIG. 6 through the gap between the lower end of the housing 14 and the plate 24. There is a concern that the force due to the pressure acts to break the oil seal 22, or the breakage of the oil seal 22 may cause the gear oil that lubricates the oil seal 22 to enter the second bearing 21 side. Further, there is a possibility that the grease in the grease chamber 30 may enter the planetary speed reduction mechanism 11. Furthermore, there is a concern that the dust seal 26 moves in the direction of the arrow 41 in FIG. 6 and protrudes greatly from the annular recess 25 or leaks grease to the outside of the turning device 4.

  The present invention has been made from the above-described prior art, and an object of the present invention is to provide a swivel device that can keep the pressure in the grease chamber in which the second bearing is disposed low.

  In order to achieve this object, a turning device according to the present invention includes a turning motor for turning a turning body, a planetary speed reduction mechanism for reducing and increasing torque of the turning motor, and rotation of the planetary speed reduction mechanism. A swivel device having a bearing housing in which an output shaft for outputting force is housed, the first bearing housed in the bearing housing, supporting the upper portion of the output shaft and supplied with gear oil, and the output shaft A second bearing that supports the lower portion of the bearing and is supplied with grease; a housing that holds the first bearing and the second bearing and that forms an outer shell of the bearing housing; and is attached to the housing, An oil seal that seals between the first bearing and the second bearing; an annular notch that is formed at the lower end of the housing and that is open to the side; and is disposed below the housing. Between the bottom And a dust seal accommodated in an annular recess formed by the plate and the notch, and a space in which the second bearing of the housing is disposed communicates with the oil seal. In the swivel device that forms the grease chamber in which the grease for lubricating the second bearing is accommodated, the pressure in the grease chamber can be released to at least one of the dust seal and the notch of the housing. It is characterized by the formation of a simple air passage.

  In the present invention configured as described above, when the internal pressure of the grease chamber becomes high, a gap due to elastic deformation of the dust seal is formed between the inner surface of the dust seal and the side wall surface of the annular recess facing the inner surface due to the high pressure. Is done. High-pressure air in the grease chamber is guided to this gap through a gap formed between the lower end of the housing and the plate. At this time, the gap formed between the inner surface of the dust seal and the side wall surface of the annular recess is in a state of communicating with the air passage formed in at least one of the dust seal and the notch of the housing. Therefore, the high-pressure air guided to the gap formed between the inner surface of the dust seal and the side wall surface of the annular recess is guided to the above-described air passage and discharged to the outside of the housing. As a result, the pressure in the grease chamber 30 decreases. That is, the pressure in the grease chamber 30 can be kept low.

  The swirl device according to the present invention is characterized in that, in the above-mentioned invention, the air passage comprises a groove portion extending along a radial direction of the dust seal.

  Further, the swivel device according to the present invention is characterized in that, in the above-mentioned invention, a supply pipe for supplying the grease to the grease chamber is provided on the output shaft so as to communicate with the grease chamber.

  Further, the turning device according to the present invention comprises, in the above invention, a device provided in a work machine having a traveling body and a turning body arranged on the traveling body, and between the traveling body and the turning body. It is characterized by being intervened in.

  In the present invention, since an air passage capable of releasing the pressure of the grease chamber is formed in at least one of the dust seal and the notch of the housing, the grease chamber in which the second bearing is disposed through the air passage. The pressure inside the grease chamber can be kept low. This can prevent the oil seal that seals between the first bearing and the second bearing from being damaged. Further, it is possible to prevent the gear oil that lubricates the first bearing from entering the second bearing side due to the breakage of the oil seal. Moreover, the large protrusion from the annular recessed part of a dust seal can be prevented. Further, it is possible to prevent the grease in the grease chamber from leaking to the outside of the swivel device due to such large protrusion of the dust seal. As a result, it is possible to realize a stable seal structure that is less likely to be damaged than in the past, and to obtain a highly reliable swivel device.

  Hereinafter, the best mode for carrying out a turning device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing a configuration of a main part of an embodiment of a turning device according to the present invention.

  The turning device 4 according to the present embodiment is also provided in a hydraulic excavator having, for example, the traveling body 1 and the turning body 3 shown in FIG. 3 described above, and is interposed between the traveling body 1 and the turning body 3 so that the turning body 4 3 is turned.

  The basic configuration of the turning device according to the present embodiment is the same as the turning device shown in FIG. 4 described above. Although the description is repeated, the turning device 4 according to the present embodiment also includes the turning motor 10 shown in FIG. 4, the planetary speed reduction mechanism 11 that decelerates and increases the torque of the turning motor 10, and the planetary speed reduction mechanism 11. And a bearing housing 12 in which the output shaft 17 to which the rotational force is transmitted is accommodated.

  The bearing housing 12 accommodates a first bearing 20 that supports the upper portion of the output shaft 17 and is supplied with gear oil, and a second bearing 21 that supports the lower portion of the output shaft 17 and is supplied with grease. ing. An oil seal 22 that seals between the first bearing 20 and the second bearing 21 is attached to the housing 14 that forms the outer shell of the bearing housing 12 and holds the first bearing 20 and the second bearing 21. ing.

  An annular recess 25 formed by an annular notch 23 formed at the lower end of the housing 14 and opened laterally, and a plate 24 disposed below the housing 14 with a first gap 46 described later, A dust seal 26 is accommodated. Further, the space in which the second bearing 21 of the housing 14 is disposed communicates with the oil seal 22 to form a grease chamber 30 in which grease for lubricating the second bearing 21 is accommodated. Further, a first supply pipe 31 and a second supply pipe 32 that are formed on the output shaft 17 so as to communicate with the grease chamber 30 and supply grease to the grease chamber 30 are provided. About these basic structures, it is equivalent to the prior art shown in FIGS.

  In the present embodiment, air capable of releasing the pressure of the grease chamber 30 on at least one of the dust seal 26 and the notch 23 of the housing 14, for example, on the upper wall surface of the notch 23, as shown in FIG. 1. A passage is formed. This air passage is composed of, for example, a groove 45 that extends along the radial direction of the dust seal 26. One groove portion 45 or a plurality of groove portions 45 may be provided.

  In the turning device 4 according to the present embodiment configured as described above, when the turning motor 10 shown in FIG. 3 is driven, the rotational force is transmitted as the rotation of the output shaft 17 via the planetary reduction mechanism 11. The rotation of the output shaft 17 is transmitted as a force for turning the swivel body 3 through meshing between the tooth portion 18 of the output shaft 17 and the inner ring 2 a of the swivel wheel 2. Various operations such as excavation of earth and sand and release of excavated earth and sand are performed by such turning of the revolving structure 3 and driving of the front working machine 5 shown in FIG.

  FIG. 2 is a longitudinal sectional view showing the operation of this embodiment.

  In the present embodiment configured as described above, as shown in FIG. 2, when the internal pressure of the grease chamber 30 becomes high, the internal pressure is applied to the first gap 46 formed between the lower end of the housing 14 and the plate 24. Further, the pressure causes a second gap 47 to be formed by elastic deformation of the dust seal 26 between the inner surface of the dust seal 26 and the side wall surface of the annular recess 25 facing the inner surface. Therefore, the high-pressure air in the grease chamber 30 is guided to the first gap 46 and the second gap 47. At this time, the second gap 47 communicates with the groove 45 formed in the upper wall surface of the notch 23 of the housing 14. Therefore, the high-pressure air guided to the second gap 47 is guided to the groove portion 45 and discharged to the outside of the housing 14. Thereby, the pressure in the grease chamber 30 in which the 2nd bearing 21 is arrange | positioned is restrained low.

  When high-pressure air is released to the groove 45 of the notch 23, the elastic deformation of the dust seal 26 and the elastic deformation of the plate 24 are released, and the inner surface of the dust seal 26 is moved to the inner surface by the elastic force of the dust seal 26. It comes into close contact again with the side wall surface of the notch 23 of the housing 14 facing the housing.

  According to the present embodiment, as described above, the pressure in the grease chamber 30 can be released through the groove 45 of the notch 23 and the pressure in the grease chamber 30 can be kept low. The high pressure of the grease chamber 30 does not act on the oil seal 22 that seals between the second bearing 21. As a result, the oil seal 22 can be prevented from being damaged. Further, since the oil seal 23 can be prevented from being damaged, it is possible to prevent the gear oil that lubricates the oil seal 22 from entering the second bearing 21 side. Further, it is possible to prevent the grease in the grease chamber 30 from entering the planetary speed reduction mechanism 11.

  Further, as shown in FIG. 2, the dust seal 26 moves in a direction away from the side wall surface of the notch 23 of the housing 14 by the high-pressure air in the grease chamber 30, and the amount of protrusion of the dust seal 23 at this time is The amount is suppressed to a small amount corresponding to the opening area of the second gap 47. Therefore, large protrusion of the dust seal 26 from the annular recess 25 can be prevented. Further, the opening area of the first gap 46 and the second gap 47 is relatively small, and the opening area of the groove 45 formed on the upper wall surface of the notch 23 of the housing 14 can be set small in advance. When the groove 45 and the grease chamber 30 communicate with each other through the first gap 46 and the second gap 47, leakage of the grease in the grease chamber 30 to the outside of the swivel device 4 can be prevented.

  By these, this embodiment can implement | achieve the stable seal structure which is hard to be damaged, and can obtain the swirl device 4 with high reliability.

  In the above embodiment, the groove 45 forming the air passage is provided in the notch 23 of the housing 14, but the present invention is not limited to such a configuration. An air passage that can communicate with the second gap 47 formed in the annular recess 25 may be provided in the dust seal 26. Further, it may be configured to be provided in both the notch 23 and the dust seal 26 of the housing 14. Even those configured as described above can release the high-pressure air to the outside of the housing 14 and keep the pressure in the grease chamber 30 low when the pressure in the grease chamber 30 increases.

It is a longitudinal cross-sectional view which shows the principal part structure of one Embodiment of the turning apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows operation | movement of this embodiment. It is a side view which shows the hydraulic shovel mentioned as an example of the working machine with which a turning apparatus is provided. It is the front view which carried out the cross section which shows the conventional turning apparatus. It is the longitudinal cross-sectional view which expanded and showed the principal part of FIG. It is a principal part longitudinal cross-sectional view explaining the problem of the conventional turning apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traveling body 2 Turning wheel 3 Turning body 4 Turning apparatus 10 Turning motor 11 Planetary speed reduction mechanism 12 Bearing box 14 Housing 17 Output shaft 20 1st bearing 21 2nd bearing 22 Oil seal 23 Notch part 24 Plate 25 Annular recessed part 26 Dust seal 30 Grease chamber 45 Groove (air passage)
46 First gap 47 Second gap (gap)

Claims (4)

A swivel having a swivel motor that swivels a swivel body, a planetary speed reduction mechanism that decelerates and increases torque of the swivel motor, and a bearing box that houses an output shaft that outputs the rotation power of the planetary speed reduction mechanism. A device,
A first bearing housed in the bearing box and supporting the upper portion of the output shaft and supplied with gear oil; a second bearing supporting the lower portion of the output shaft and supplied with grease; and the first bearing And a housing that holds the second bearing and forms an outer shell of the bearing box, an oil seal that is attached to the housing and seals between the first bearing and the second bearing, and a lower end of the housing An annular notch that is formed on the side and is open on the side, a plate that is disposed below the housing and forms a gap between the lower end of the housing, and the plate and the notch A dust seal accommodated in the annular recess formed,
In a swivel device in which a space portion in which the second bearing of the housing is disposed communicates with the oil seal to form a grease chamber in which the grease for lubricating the second bearing is accommodated.
A swiveling device, wherein an air passage capable of releasing the pressure of the grease chamber is formed in at least one of the dust seal and the notch of the housing. The swivel device according to claim 1,
The swivel device characterized in that the air passage comprises a groove extending along the radial direction of the dust seal. The swivel device according to claim 1,
A swiveling device, characterized in that a supply pipe for supplying the grease to the grease chamber is provided on the output shaft so as to communicate with the grease chamber. The swivel device according to any one of claims 1 to 3,
A turning device comprising a traveling machine and a work machine having a turning body disposed on the traveling body, the turning device being interposed between the traveling body and the turning body.

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