JP2013209019A - Seal structure of endless track driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal structure of an endless track driving device which prevents penetration of foreign matter such as mud and reduces a frictional loss.SOLUTION: A seal structure of an endless track driving device 1 includes: a first O-ring 42 (first elastic member) which energizes a seal ring 50 disposed on a stationary housing 10 in a direction of extruding the seal ring 50 from a first storage groove 45; a slide ring 60 which is disposed on a rotation casing 20 and has a higher rigidity than the seal ring 50; and a second O-ring 41 (second elastic member) which energizes the slide ring 60 in a direction of pushing the slide ring 60 against the seal ring 50, wherein a radial opening width L44 of a second storage groove 44 is formed larger than a radial opening width L45 of the first storage groove 45 and slide gaps 58, 59 are disposed between the groove lateral surfaces 44A, 44B of the second storage groove 44 and the slide ring 60.

Description

  The present invention relates to a seal structure that seals the inside of an endless track drive device of a vehicle.

  For example, when an endless track vehicle such as a hydraulic excavator travels on muddy mud at a civil engineering work site or the like, an endless track drive device that drives the endless track zone may be covered with mud and rotate. In such an endless track drive device, a labyrinth seal and a floating seal are provided between a fixed housing attached to the vehicle and a rotating casing that drives the endless track as a seal structure for preventing foreign matters such as mud from entering. There is what is provided (see Patent Document 1).

  This type of labyrinth seal has a crank-shaped gap that is defined around the floating seal and prevents foreign matter such as mud from entering the floating seal. .

  The floating seal includes a pair of metal seal rings mounted via a pair of O-rings between the fixed housing and the inner wall surface of the rotary casing, and the seal rings pushed by the O-rings are in sliding contact with each other. Accordingly, the lubricating oil in the apparatus is sealed so as not to leak to the outside, and foreign substances are prevented from entering the apparatus from the outside.

JP 2001-248735 A

  However, in such a conventional endless track drive device seal structure, the rotating casing is eccentric with respect to the fixed housing due to the backlash of the bearing, and the distance between the rotating casing and the fixed housing in which the floating seal is interposed is set. Since it increases or decreases in the rotational circumferential direction, there is a problem that it is difficult to prevent intrusion of foreign matters such as mud by a floating seal.

  In addition, the floating seal has a large amount of frictional heat generated at the sliding contact portion between the metal seal rings, so there is a concern that the lubricating oil and sealing material in the device may be overheated, and the friction loss of the floating seal is large. was there.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a seal structure for an endless track drive device that prevents intrusion of foreign matter such as mud and reduces friction loss.

  The present invention relates to a seal structure for an endless track drive device that shields between a rotating casing that drives an endless track zone of a vehicle and a fixed housing, and an annular first receiving groove provided in one of the rotating casing and the fixed housing And a seal ring housed in the first housing groove, a first elastic member that urges the seal ring in a direction to push the seal ring out of the first housing groove, and the first housing groove opposite to the first housing groove. An annular second receiving groove that opens, a slide ring that is housed in the second housing groove and has higher rigidity than the seal ring, and a second that is housed in the second housing groove and urges the slide ring against the seal ring. An elastic member, the first receiving groove has a groove side surface extending in the rotation axis direction of the rotating casing, and the second receiving groove is a groove side extending in the rotation axis direction of the rotating casing. The radial opening width of the second receiving groove is formed larger than the radial opening width of the first receiving groove, and a slide gap is provided between the groove side surface of the second receiving groove and the slide ring. To do.

  In the present invention, when the rotating casing is eccentrically rotated with respect to the fixed housing due to the backlash of the bearing or the like, the slide ring is located concentrically with the seal ring in the slide gap provided inside the second receiving groove. It becomes possible to move in the rotational radius direction. Accordingly, the followability of sliding contact with the seal ring so as not to be separated from the slide ring is ensured, and an operating state is maintained that shields between the rotating casing and the fixed housing and prevents entry of foreign matters such as mud.

  Since the seal ring is housed in the first housing groove and is in sliding contact with the slide ring having relatively high rigidity, the required rigidity is kept low, and a low friction resin material can be used. Furthermore, it is possible to appropriately adjust the force for pressing the seal ring against the slide ring by arbitrarily setting the material and shape of the first elastic member and the second elastic member. Thereby, the friction loss which arises in the sliding contact part of a seal ring and a slide ring can be reduced.

It is sectional drawing of the endless track drive apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing of the seal structure of the endless track drive apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing of the seal structure which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
(First embodiment)
FIG. 1 is a cross-sectional view showing a seal structure of an endless track drive device 1 provided in a crawler type vehicle such as a hydraulic excavator. The endless track drive device 1 includes a rotating casing (hub) 20 that rotates with respect to the fixed housing 10, and a sprocket (crawler wheel) (not shown) is connected to the rotating casing 20. When the rotary casing 20 is rotated, an unillustrated endless track (crawler belt) meshing with the sprocket circulates so that the vehicle travels.

  The fixed housing 10 is connected to a vehicle frame (not shown). A hydraulic motor 2 is provided inside the fixed housing 10. For example, a swash plate type piston motor is used as the hydraulic motor 2, and the hydraulic motor 2 is rotated about a rotation axis O by hydraulic oil supplied from a hydraulic source (not shown).

  The rotating casing 20 is rotatably supported via the bearing 3 with respect to the fixed housing 10. The rotary casing 20 rotates around the rotation axis O.

  A reduction gear mechanism 5 (not shown) is provided inside the rotary casing 20. The reduction gear mechanism 5 decelerates the output rotation of the hydraulic motor 2 and transmits it to the rotary casing 20. A gear chamber 9 that houses the reduction gear mechanism 5 is defined inside the rotary casing 20.

  The cylindrical rotating casing 20 is formed with a rotating flange portion 25 that protrudes annularly from the outer wall portion 22 thereof. The rotary flange portion 25 has a rotary flange end surface 26 extending in a radial direction orthogonal to the rotation axis O, and a plurality of screw holes 29 are formed in the rotary flange end surface 26. The above-described sprocket (crawler wheel) is assembled so as to contact the end face 26 of the rotating flange, is fastened to the rotating flange portion 25 via a bolt (not shown) that is screwed into the screw hole 29, and rotates together with the rotating casing 20. Operate.

  A labyrinth seal 30 is provided between the fixed housing 10 and the rotating casing 20. The labyrinth seal 30 is defined between an annular concave portion 13 formed in the fixed housing 10 and an annular convex portion 23 formed in the rotary casing 20. Thereby, the labyrinth seal 30 has a cross-sectional shape bent in a crank shape, and prevents foreign matters such as mud from entering the gear chamber 9.

  The labyrinth seal 30 has a radial seal gap 31 whose one end opens to the outside of the endless track drive device 1, an axial seal gap 32 whose one end is connected to the other end of the radial seal gap 31, and this axial direction. The seal gap 32 is constituted by a radial seal gap 33 having one end connected to the other end of the seal gap 32. An axial seal gap 34 having one end connected to the other end of the radial seal gap 33 is provided, and the other end of the axial seal gap 34 opens around the bearing 3 of the gear chamber 9. The radial seal gaps 31 and 33 define a disk-like space extending in the radial direction orthogonal to the rotation axis O. The axial seal gaps 32 and 34 define a cylindrical space extending in the direction of the rotation axis O.

  A seal unit 40 that shields the radial seal gap 33 of the labyrinth seal 30 is provided. The seal unit 40 is formed in the rotary casing 20, a seal ring 50 that is accommodated in the first accommodation groove 45, a first O-ring 42 that urges the seal ring 50 in a direction to push the seal ring 50 out of the first accommodation groove 45. An annular second receiving groove 44, a slide ring 60 received in the second receiving groove 44, a second O-ring 41 that urges the slide ring 60 in a direction to press the seal ring 50, and a fixed housing 10, an annular first receiving groove 45 formed in the main body 10.

  The radial seal gap 33 is defined between the bottom surface 19 of the annular recess 13 of the fixed housing 10 and the end surface 28 of the annular projection 23 of the rotary casing 20.

  An annular first receiving groove 45 opens in the bottom surface 19 of the annular recess 13. On the other hand, an annular second accommodation groove 44 opens in the end face 28 of the annular convex portion 23. The first accommodation groove 45 and the second accommodation groove 44 are opened so as to face each other at the same position in the radial direction orthogonal to the rotation axis O.

  The first housing groove 45 has groove side surfaces 45A and 45B extending in the direction of the rotation axis O, and a groove bottom surface 45C extending in the radial direction orthogonal to the rotation axis O.

  The radial opening width L45 of the first receiving groove 45 is a length (interval) extending between the groove side surfaces 45A and 45B in the radial direction orthogonal to the rotation axis O, and with respect to the radial thickness T50 of the seal ring 50. It is set to have a predetermined Saddle Ice Care.

  The second housing groove 44 has groove side surfaces 44A and 44B extending in the direction of the rotation axis O, and a groove bottom surface 44C extending in the radial direction perpendicular to the rotation axis O.

  The radial opening width L44 of the second housing groove 44 is a length (interval) extending between the groove side surfaces 44A and 44B in the radial direction orthogonal to the rotation axis O. The radial opening width L44 of the second housing groove 44 is formed larger than the radial opening width L45 of the first housing groove 45. On the other hand, the thickness T60 of the slide ring 60 and the radial thickness T50 of the seal ring 50 are formed to be equal.

  The slide ring 60 includes a slide surface 61 that faces the seal ring 50, a ring end surface 62 that conforms to the rectangular cross-sectional shape of the second receiving groove 44, and both ring side surfaces (outer peripheral surface, inner peripheral surface) 63, 64. . The outer diameter of the slide ring 60 (the outer diameter of the ring side surface 63) is formed larger than the outer diameter of the seal ring 50.

  As described above, the radial opening width L44 of the second receiving groove 44 is formed to be larger than the radial opening width L45 of the first receiving groove 45, and between the slide ring 60 and the inner side of the second receiving groove 44, Are provided with slide gaps 58 and 59. The slide gap 58 is annularly defined between the groove side surface 44 </ b> A of the second accommodation groove 44 and the ring side surface (outer peripheral surface) 63 of the slide ring 60. The slide gap 59 is annularly defined between the groove side surface 44 </ b> B of the second accommodation groove 44 and the ring side surface (inner peripheral surface) 64 of the slide ring 60.

  The first receiving groove 45 and the second receiving groove 44 face each other across the radial seal gap 33, and each define an annular space having a rectangular cross section. The first receiving groove 45 having a small radial opening width L45 is disposed concentrically so as to face the central portion of the second receiving groove 44 having a large radial opening width L44.

  The slide surface 61 with which the seal ring 50 comes into sliding contact is formed in a tapered shape (conical frustum shape) that is inclined with respect to the rotation axis O.

  The slide ring 60 is made of metal and has higher rigidity than a seal ring 50 described later. The slide ring 60 is not limited to the configuration described above, and may be formed of a resin material such as polyamide.

  The slide ring 60 is formed in a ring shape having no abutment, and the entire circumference thereof is fitted over the second accommodation groove 44 and the first accommodation groove 45. Since the slide ring 60 and the second accommodation groove 44 and the first accommodation groove 45 are both formed in an annular shape extending in the direction of the rotation axis O, it is not necessary to provide the slide ring 60 with an abutment. The second receiving groove 44 and the first receiving groove 45 can be fitted.

  The second O-ring 41 is provided as a second elastic member that pushes the slide ring 60 out of the second accommodation groove 44. The second O-ring 41 has a circular or oval cross section in a free state, and is formed in a ring shape from a rubber material. The second O-ring 41 is compressed and interposed in the second receiving groove 44 on the inner side (back side) of the slide ring 60, and presses the ring end surface 62 of the slide ring 60.

  The slide ring 60 is interposed in the first accommodation groove 45 and the second accommodation groove 44 so that the slide surface 61 faces inward (downward in FIG. 2) in the radial direction. As will be described later, the slide ring 60 moves outward (upward in FIG. 2) in the radial direction by a reaction force from the seal ring 50 received by the slide surface 61. As a result, one ring side surface 63 abuts against and presses against the groove side surface 45A of the first receiving groove 45, and a gap is formed between the ring side surface 63 and the groove side surface 44A of the second receiving groove 44, and the other ring A gap is formed between the side surface 64 and the groove side surface 44 </ b> B of the second accommodation groove 44.

  The seal ring 50 includes a seal portion 51 facing the slide surface 61, a ring end surface 52 and both ring side surfaces (outer peripheral surface, inner peripheral surface) 53, 54 along a substantially rectangular cross-sectional shape of the first receiving groove 45. Have.

  The seal portion 51 slidably contacting the slide surface 61 is formed in a tapered shape (conical frustum shape) that is inclined with respect to the rotation axis O. The seal portion 51 is not limited to the configuration described above, and may have a configuration having a lip portion that protrudes in an annular shape with respect to the slide surface 61.

  The seal ring 50 is formed of, for example, a PTFE (polytetrafluoroethylene) resin material, but is not limited thereto, and other low friction resin materials may be used.

  Since the seal ring 50 is formed of a low friction resin material, the friction coefficient of the seal ring 50 with respect to the slide surface 61 formed of metal is suppressed to be smaller than that of the sliding contact portion between the metals in the conventional floating seal.

  The seal ring 50 is formed in a ring shape having no abutment, and the entire circumference is fitted over the first accommodation groove 45 and the second accommodation groove 44. Since the seal ring 50 and the first receiving groove 45 and the second receiving groove 44 are both formed in an annular shape extending in the direction of the rotation axis O, it is not necessary to provide the seal ring 50 with an abutment. The first receiving groove 45 and the second receiving groove 44 can be fitted.

  The first O-ring 42 is provided as a first elastic member that presses the seal ring 50 against the slide surface 61, and is formed in a ring shape from a rubber material. The first O-ring 42 has a circular or oval cross section in a free state. The first O-ring 42 is compressed and interposed in the first receiving groove 45 on the outer side (back side) of the seal ring 50 and presses the ring end surface 52 of the seal ring 50.

  The force with which the seal ring 50 is pressed against the slide ring 60 is obtained by the elastic restoring force of the second O-ring 41 and the first O-ring 42 and the elastic restoring force of the seal ring 50 itself. By setting, the frictional force generated between the seal ring 50 and the slide surface 61 can be kept small.

  The seal ring 50 is interposed in the first accommodation groove 45 and the second accommodation groove 44 so that the tapered seal portion 51 faces outward in the radial direction (upward in FIG. 2). The seal ring 50 moves inward (downward in FIG. 2) in the radial direction by a reaction force received by the seal portion 51 from the slide surface 61. Thereby, one ring side surface 54 is pressed against the groove side surface 45B of the first receiving groove 45, and a gap is formed between the ring side surface 54 and the groove side surface 44B of the second receiving groove 44, and the other ring side surface 54 is pressed. A gap is formed between 53 and the groove side surface 45A of the first receiving groove 45.

  Hereinafter, the operation of the endless track drive apparatus 1 will be described.

  During traveling of the vehicle, the endless track drive device 1 causes the hydraulic motor 2 to rotate the rotating casing 20 and circulate an unillustrated endless track (crawler belt) meshed with a sprocket that rotates together with the rotating casing 20. When the vehicle travels on muddy mud, the endless track belt circulates while sinking in the mud, and the endless track drive device 1 is also covered with mud and operates.

  During the above operation, the endless track drive device 1 prevents foreign matter such as mud from entering by the labyrinth seal 30, and the radial seal gap 33 of the labyrinth seal 30 is sealed by the seal unit 40. The lubricating oil in the chamber 9 is sealed so as not to leak out.

  Since the second receiving groove 44 opens in the end face 28 of the annular convex portion 23, the axial seal gap 32 of the labyrinth seal 30 extends so as to surround the slide ring 60 and the second O-ring 41 in the annular convex portion 23. For this reason, the length of the labyrinth seal 30 is sufficiently secured by using the interposing space of the seal unit 40. Thereby, it is possible to effectively suppress the entry of foreign matter such as mud around the seal unit 40 by the labyrinth seal 30 and to suppress the increase in size of the fixed housing 10 and the rotary casing 20.

  When the endless track driving device 1 is used in an environment where earth and sand, muddy water, etc. are present as described above, mud or the like adhering to the outer wall 12 of the fixed housing 10 and the rotating casing 20 may be pushed into the labyrinth seal 30. is there.

  Even if foreign matter such as mud that has entered the labyrinth seal 30 enters the radial seal gap 33, the slide ring 60 fits over the first receiving groove 45 and the second receiving groove 44, and the second O-ring 41 is attached. Since the radial seal gap 33 of the labyrinth seal 30 is shielded through, foreign matter is prevented from entering the gear chamber 9. Since the slide ring 60 has higher rigidity than the seal ring 50, deformation and damage due to mud or the like that has entered the labyrinth seal 30 can be suppressed, and sufficient durability can be obtained.

  On the other hand, the seal portion 51 of the seal ring 50 is brought into sliding contact with the slide surface 61 by the elastic restoring force of the first O-ring 42 and the second O-ring 41, and the space between the rotary casing 20 and the fixed housing 10 is sealed by this sliding contact portion. . Thereby, it seals so that the lubricating oil of the gear chamber 9 may not leak outside.

  During the operation of the endless track drive device 1, the rotary casing 20 is eccentrically rotated with respect to the fixed housing 10 due to the backlash of the bearing 3, and the gap width of the radial seal gap 33 (the annular recess 13 in the direction of the rotation axis O). The distance between the bottom surface 19 and the end surface 28 of the annular projection 23) increases or decreases by, for example, several millimeters in the rotational circumferential direction. Thus, the seal ring 50 pushed by the elastic restoring force of the first O-ring 42 rotates along the groove side surface 45 </ b> B of the first receiving groove 45 in response to the eccentricity of the rotary casing 20 with respect to the fixed housing 10. Move in the direction of axis O. On the other hand, the slide ring 60 pushed by the elastic restoring force of the second O-ring 41 moves along the groove side surface 44 </ b> A of the second housing groove 44 in the direction of the rotation axis O and follows the seal ring 50.

  As described above, when the rotary casing 20 rotates eccentrically with respect to the fixed housing 10, a swinging motion in which the rotation axis O of the rotary casing 20 slightly tilts with respect to the center line of the fixed housing 10 is performed. Correspondingly, the radial opening width L44 of the second receiving groove 44 is formed to be larger than the radial opening width L45 of the first receiving groove 45, and between the slide ring 60 and the inside of the second receiving groove 44, Since the slide gaps 58 and 59 are provided, the slide ring 60 moves in a radial direction to a position concentric with the seal ring 50 and follows the seal ring 50. At this time, a centering function is achieved in which the slide ring 60 moves so that the slide ring 60 comes to be concentric with the seal ring 50 by bringing the tapered slide surface 61 into sliding contact with the seal portion 51 of the seal ring 50. Accordingly, it is possible to prevent gaps between the seal portion 51 of the seal ring 50 and the slide surface 61 of the slide ring 60, and to prevent foreign matters such as mud from entering the gear chamber 9, and The operation state of sealing so that the lubricating oil does not leak to the outside is maintained.

  When mud or the like that has entered the labyrinth seal 30 and is shielded by the seal unit 40 enters the second housing groove 44 through the gap between the slide ring 60 and the groove side surface 44A of the second housing groove 44, the mud or the like It is confined in the second accommodation groove 44 through the two O-rings 41 and mud etc. are prevented from entering the gear chamber 9. Mud or the like that has entered the second housing groove 44 compresses the second O-ring 41, and the slide surface 61 of the slide ring 60 that is pressed by the second O-ring 41 is pressed against the seal portion 51 of the seal ring 50. The sealing performance between the ring 50 and the slide ring 60 is enhanced. Further, even if mud or the like entering the labyrinth seal 30 and shielded by the seal unit 40 enters the first receiving groove 45 through the gap between the seal ring 50 and the groove side surface 45A of the first receiving groove 45, the mud or the like Is confined in the first accommodation groove 45 through the first O-ring 42, and mud or the like is prevented from entering the gear chamber 9. Mud or the like that has entered the first receiving groove 45 compresses the first O-ring 42, and the seal portion 51 of the seal ring 50 that is pressed by the first O-ring 42 is pressed against the slide surface 61 of the slide ring 60. The sealing performance between the ring 50 and the slide ring 60 is enhanced.

  According to the above embodiment, there exists an effect shown below.

  [1] An annular first accommodation groove 45 provided in the fixed housing 10, an annular second accommodation groove 44 provided in the rotary casing 20 and opening facing the first accommodation groove 45, and the first accommodation groove 45. A seal ring 50 to be housed, a first O-ring 42 (first elastic member) that is housed in the first housing groove 45 and urges the seal ring 50 in a direction to push out the first housing groove 45, and a second housing groove 44. And a second O-ring 41 (second elastic member) that is urged in a direction of pressing the slide ring 60 against the seal ring 50, which is received in the second receiving groove 44. The first housing groove 45 has groove side surfaces 45A and 45B extending in the direction of the rotation axis O of the rotary casing 20, and the second storage groove 44 is a groove side extending in the direction of the rotation axis O of the rotary casing 20. 44A, 44B, the radial opening width L44 of the second receiving groove 44 is formed larger than the radial opening width L45 of the first receiving groove 45, the groove side surfaces 44A, 44B of the second receiving groove 44 and the slide ring 60. Since the slide gaps 58 and 59 are provided between them, the slide gap 58 provided inside the second receiving groove 44 when the rotary casing 20 rotates eccentrically with respect to the fixed housing 10 due to the backlash of the bearing 3 or the like. 59, the slide ring 60 moves radially to a position that is concentric with the seal ring 50, and the followability of sliding contact so that the seal ring 50 is not separated from the slide ring 60 is ensured. Thereby, the operation state which shields between the rotation casing 20 and the stationary housing 10 and prevents intrusion of foreign matters such as mud is maintained.

  Since the seal ring 50 is housed in the first housing groove 45 and is in sliding contact with the slide ring 60 having relatively high rigidity, the required rigidity is kept low, and a low friction resin material can be used. The material shapes of the first O-ring 42 and the second O-ring 41 can be arbitrarily set, and the force for pressing the seal ring 50 against the slide ring 60 can be appropriately adjusted. As a result, the friction loss generated in the sliding contact portion between the seal ring 50 and the slide ring 60 is reduced to reduce the fuel consumption of the vehicle, and the lubricating oil and the sealing material in the endless track drive device 1 are overheated by the frictional heat. This will extend the life of these products.

  In addition, not only the structure mentioned above but the 1st accommodation groove which accommodates a seal ring in a rotation casing is provided, and it is good also as a structure provided with the 2nd accommodation groove which accommodates a slide ring in a fixed housing. In this case, the slide ring does not rotate, and the seal ring rotates with the rotating casing.

  [2] Since the slide ring 60 has a tapered slide surface 61 inclined with respect to the rotation axis O of the rotary casing 20, and the seal ring 50 has a seal portion 51 slidably contacting the slide surface 61, the first O-ring 42 and the second O-ring 41 are elastically restored by the taper-shaped slide surface 61 of the slide ring 60 against the seal portion 51 of the seal ring 50, whereby a slide gap 58 provided inside the second receiving groove 44, At 59, a centering function is obtained in which the slide ring 60 moves radially to a position concentric with the seal ring 50.

  [3] Since the slide ring 60 is interposed so as to contact the groove side surface 45A located on the outer side of the first receiving groove 45 (the side communicating with the outside through the labyrinth seal 30), the slide ring 60 is relatively rigid. The high slide ring 60 prevents intrusion of mud and the like, and sufficient durability is obtained.

(Second Embodiment)
Next, a second embodiment of the present invention shown in FIG. 3 will be described. FIG. 3 is a cross-sectional view of a seal structure including the seal unit 49. Since this configuration is basically the same as that of the first embodiment, only differences from the first embodiment will be described below. In addition, the same code | symbol is attached | subjected to the structure same as 1st Embodiment.

  The seal unit 49 includes a first X ring 47 as a first elastic member and a second X ring 46 as a second elastic member.

  The first X ring 47 has an X-shaped cross section composed of four convex portions 47A to 47D, and is formed in a ring shape from a rubber material. The first X ring 47 is compressed and interposed in the first receiving groove 45 on the outer side (back side) of the seal ring 50, and presses the ring end surface 52 (see FIG. 2) of the seal ring 50 by its elastic restoring force. Then, the seal ring 50 is pressed against the slide ring 60.

  A housing space having a rectangular cross section is defined in the first housing groove 45, and the portions defining the housing space are the groove side surface 45 </ b> A, the groove bottom surface 45 </ b> C, the groove side surface 45 </ b> B, and the ring of the seal ring 50. The end face 52 has four annular corners. The convex portions 47 </ b> A to 47 </ b> D of the first X ring 47 abut against the four annular corners that define the accommodation space, and seal between the seal ring 50 and the first accommodation groove 45. As the pressure in the first receiving groove 45 increases, the convex portions 47A to 47D of the first X ring 47 are pressed against the contact portion, and the sealing performance between the seal ring 50 and the first receiving groove 45 increases. The force with which the seal ring 50 is pressed against the slide ring 60 increases, and the sealing performance between the seal ring 50 and the slide ring 60 increases.

  The second X ring 46 has an X-shaped cross section composed of four convex portions 46A to 46D, and is formed in a ring shape from a rubber material. The second X-ring 46 is interposed in the second receiving groove 44 by being compressed inside the slide ring 60 (back side), and presses the ring end surface 62 (see FIG. 2) of the slide ring 60 by its elastic restoring force. Then, the slide ring 60 is pressed against the seal ring 50.

  An accommodation space having a rectangular cross section is defined in the second accommodation groove 44, and the portions defining the accommodation space are the groove side surface 44 </ b> A, the groove bottom surface 44 </ b> C, the groove side surface 44 </ b> B, and the slide ring 60 ring. The end face 62 has four annular corners. The convex portions 46 </ b> A to 46 </ b> D of the second X ring 46 abut on the four annular corners that define the accommodation space, and seal between the slide ring 60 and the second accommodation groove 44. As the pressure in the second housing groove 44 increases, the convex portions 46A to 46D of the second X ring 46 are pressed against the contact portion, and the sealing performance between the slide ring 60 and the second housing groove 44 is increased. The force with which the slide ring 60 is pressed against the seal ring 50 increases, and the sealing performance between the slide ring 60 and the seal ring 50 increases.

  According to the above 2nd Embodiment, while exhibiting the effect of said [1]-[3] similarly to 1st Embodiment, there exists an effect shown below.

  [4] Since the first and second X rings 47 and 46 having an X-shaped cross section are provided as the first and second elastic members, the first and second X rings 47 and 46 are the first and second receiving grooves 45. , 44 is elastically deformed by the pressure inside the seal ring 50, the sealing performance between the seal ring 50 and the first accommodation groove 45 and between the slide ring 60 and the second accommodation groove 44 is enhanced, and the seal between the seal ring 50 and the slide ring 60 is sealed. Increases nature.

  In the first and second embodiments, the first elastic member and the second elastic member are both O-rings or both are X-rings. However, the present invention is not limited to this configuration. One of the first elastic member and the second elastic member may be an O-ring and the other may be an X-ring.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The seal structure of the endless track drive device of the present invention can be used for construction machines such as a hydraulic excavator and other vehicles that travel by circulating through the endless track (crawler).

DESCRIPTION OF SYMBOLS 1 Endless track drive apparatus 10 Fixed housing 20 Rotating casing 41 2nd O-ring (2nd elastic member)
42 First O-ring (first elastic member)
44 Second receiving groove 45 First receiving groove 44A, 44B, 45A, 45B Groove side face 46 Slide face 46 Second X ring (second elastic member)
47 1st X Ring (1st elastic member)
50 Seal ring 51 Seal part 58, 59 Slide gap 60 Slide ring 61 Slide surface

Claims (4)

A seal structure of an endless track drive device that shields between a rotating casing and a fixed housing that drives an endless track zone of a vehicle,
An annular first receiving groove provided in one of the rotating casing and the fixed housing;
A seal ring received in the first receiving groove;
A first elastic member that urges the seal ring in a direction of pushing out the first receiving groove;
An annular second receiving groove provided on the other of the rotating casing and the fixed housing and opening facing the first receiving groove;
A slide ring accommodated in the second accommodation groove and having higher rigidity than the seal ring;
A second elastic member housed in the second housing groove and biased in a direction to press the slide ring against the seal ring,
The first receiving groove has a groove side surface extending in the rotation axis direction of the rotating casing,
The second receiving groove has a groove side surface extending in the rotation axis direction of the rotating casing,
The radial opening width of the second receiving groove is formed larger than the radial opening width of the first receiving groove,
A seal structure for an endless track drive device, wherein a slide gap is provided between a groove side surface of the second receiving groove and the slide ring. The slide ring has a tapered slide surface inclined with respect to the rotation axis of the rotary casing,
The seal structure of the endless track drive device according to claim 1, wherein the seal ring has a seal portion that is in sliding contact with the slide surface.   The seal structure of the endless track drive device according to claim 1, wherein the slide ring is interposed so as to abut on a side surface of the groove located on the outer side of the first receiving groove.   The seal structure for an endless track drive device according to any one of claims 1 to 3, wherein an X-ring having an X-shaped cross section is provided as the first and second elastic members.

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