JP2009068506A - Speed reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly maintain the sealing performance of a floating seal by preventing a foreign object from intruding into the floating seal through a gap between a fixed side housing and a rotary side housing. <P>SOLUTION: In the radial direction inner side of the gap 22 formed between a counter face 12E of a seal applied part 12D provided on the fixed side housing 12 and a counter face 15B of a seal applied part 15A provided on the flange 15 of the rotary side housing 14, an annular block ring 39 is provided to block this gap 22. By this, the foreign object such as earth, sand and the like is prevented by the block ring 39 from intruding into the floating seal 34 through the gap 22 so that the sealing performance of the floating seal 34 can properly be maintained. As a result, a sufficient lubricating oil L can be secured inside the rotary side housing 14, and the rotary side housing can be smoothly rotated in the long run. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a speed reducer suitably used for a hydraulic excavator, a hydraulic crane traveling device, and the like.

  Generally, a lower traveling body of a tracked vehicle such as a hydraulic excavator is provided with a track frame having left and right side frames, a traveling device provided at one end side of each side frame, and a second end side of each side frame. And a crawler belt wound around the idler wheel and a drive wheel (sprocket) provided in the traveling device.

  The traveling device of the hydraulic excavator is usually composed of a hydraulic motor that serves as a rotation source and a reduction device that decelerates and outputs the rotation of the hydraulic motor. The reduction device includes a stationary housing that houses the rotation source. A rotation-side housing rotatably provided to the fixed-side housing and driven by a rotation source; a reduction mechanism that is housed in the rotation-side housing and decelerates rotation of the rotation source; a fixed-side housing and a rotation-side housing; In order to seal the gap between the two, a floating seal provided on the inner peripheral side of the gap is provided.

  Here, the gap between the stationary housing and the rotating housing is formed in an annular shape between the opposed surfaces of the stationary housing and the rotating housing facing each other, and the floating seal is formed within the gap. A pair of seal rings arranged on the circumferential side and having sliding contact surfaces that are in sliding contact with each other, and between the one seal ring and the fixed-side housing and between the other seal ring and the rotation-side housing across the gap. And a pair of O-rings provided between the two (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 55-105661

  When the rotation side housing is driven by the hydraulic motor and rotates with respect to the fixed side housing, the clearance between the fixed side housing and the rotation side housing is sealed in a liquid-tight manner by a floating seal. The lubricating oil is sealed, and the speed reduction mechanism accommodated in the rotating side housing can be properly lubricated with the lubricating oil.

  However, since a tracked vehicle such as a hydraulic excavator travels on rough terrain such as a muddy ground, foreign matter such as earth and sand enters a gap between the stationary housing and the rotating housing. And the earth and sand etc. which entered into the gap between the stationary housing and the rotating housing are not discharged to the outside, but are accumulated toward the floating seals arranged on the inner peripheral side of these housings. .

  For this reason, the pressure of the accumulated earth and sand (the earth and sand pressure) acts on the floating seal, so that the earth and sand enters between the sliding contact surfaces of the pair of seal rings and damages the sliding contact surface. It will decline. Moreover, when soil and sand enters between the sliding contact surfaces of the pair of seal rings and heat is generated due to abnormal wear, the O-ring made of a rubber material is deteriorated by this heat, and the sealing performance of the floating seal is lowered. .

  As a result, the lubricating oil sealed in the rotary housing by the floating seal leaks to the outside, and the speed reduction mechanism cannot be properly lubricated over a long period of time, reducing the reliability of the entire speed reduction device. There is a problem of end up.

  The present invention has been made in view of the above-described problems of the prior art, and prevents foreign matter from entering the floating seal through a gap formed between the stationary housing and the rotating housing, thereby improving the sealing performance of the floating seal. An object of the present invention is to provide a speed reducer that can be maintained appropriately.

  In order to solve the above-described problems, the present invention provides a fixed housing provided with a rotation source, a rotation housing provided rotatably with respect to the fixed housing and driven by the rotation source, and the rotation housing. A reduction mechanism that is housed and decelerates rotation of the rotation source, and a floating seal that is provided radially inside the gap to seal the gap in the axial direction between the stationary housing and the rotation housing. It is applied to the reduction gear provided.

  A feature of the configuration adopted by the invention of claim 1 is that the gap between the fixed housing and the rotary housing is an annular shape that blocks the gap and prevents foreign matter from entering the floating seal. Is provided with a closing ring.

  According to a second aspect of the present invention, the closing ring is an oil-containing blocking ring formed using a polymer material and impregnated with a lubricating oil, or a self-lubricating blocking ring formed using a resin material having self-lubricating properties. It is in the configuration.

  According to a third aspect of the present invention, a gap between the stationary housing and the rotating housing is formed in an annular shape between an opposing surface of the stationary housing and an opposing surface of the rotating housing that face each other. The floating seal includes a pair of seal rings that are disposed radially inward of the gap and have sliding contact surfaces that are in sliding contact with each other, and one of the seal rings with the gap interposed therebetween, and the stationary housing. And a pair of O-rings spaced apart in the axial direction between the other seal ring and the inner peripheral surface of the rotation-side housing, It exists in the structure which is located between O-rings and is arrange | positioned radially outside the sliding contact surface of each said seal ring, and obstruct | occludes the said clearance gap.

  According to the first aspect of the present invention, the axial gap formed between the stationary housing and the rotating housing that rotate relative to each other can be closed by the closing ring provided on the radially inner side of the gap. Accordingly, foreign matter such as earth and sand can be prevented from entering the floating seal through the gap between the stationary housing and the rotating housing by the closing ring. As a result, the sealing performance of the floating seal can be maintained over a long period of time. For example, the lubricating oil filled in the rotating side housing is securely sealed by the floating seal and accommodated in the rotating side housing by the lubricating oil. By properly lubricating the reduced speed reduction mechanism, it is possible to improve the reliability of the entire speed reduction device.

  According to the invention of claim 2, the occlusion ring is an oil-containing occlusion ring formed using a polymer material and impregnated with a lubricating oil, or a self-lubricating occlusion ring formed using a resin material having self-lubricating properties. It is composed by. Therefore, when a closing ring is provided in the gap between the fixed side housing and the rotating side housing, even if the closing ring is in sliding contact with the fixed side housing and the rotating side housing, the housing and the closing ring The friction between them can be suppressed. For this reason, wear of the closing ring can be suppressed and the life can be extended, and the rotating side housing can be smoothly rotated with respect to the fixed side housing.

  According to the invention of claim 3, the closing ring is located between the O-rings of the floating seal and arranged radially outside the sliding contact surface of each seal ring, and between the fixed side housing and the rotary side housing. Therefore, the sliding contact surfaces of the seal rings and the O-rings constituting the floating seal can be protected from foreign matters such as earth and sand. Thereby, the sealing performance of the floating seal can be maintained over a long period of time, and the lubricating oil filled in the rotation side housing can be reliably sealed by the floating seal.

  Hereinafter, the embodiment of the speed reducer according to the present invention will be described in detail with reference to the accompanying drawings, taking as an example the case of applying to a traveling device of a hydraulic excavator.

  In the figure, reference numeral 1 denotes a hydraulic excavator. The hydraulic excavator 1 is a self-propelled track-type (crawler type) lower traveling body 2 and an upper revolving body mounted on the lower traveling body 2 in a swingable manner. 3 and a work device 4 that is provided on the front side of the upper swing body 3 so as to be able to move up and down and performs excavation work such as earth and sand.

  Here, the lower traveling body 2 is provided on the track frame 5 having left and right side frames 5A (only the left side is shown) extending in the front and rear directions, and one end side in the longitudinal direction of each side frame 5A. A travel device 8 described later, idle wheels 6 provided on the other end side in the longitudinal direction of each side frame 5A, and crawler belts 7 wound around the idle wheels 6 and drive wheels 21 described later are roughly configured. ing.

  Reference numeral 8 denotes a traveling device of the hydraulic excavator 1, and the traveling device 8 is attached to the traveling device bracket 9 and a traveling device bracket 9 fixed to one end side in the longitudinal direction of each side frame 5A as shown in FIG. The hydraulic motor 10 as a rotation source and a speed reducer 11 (described later) that decelerates the rotation of the hydraulic motor 10 are roughly configured. The traveling device 8 decelerates the rotation of the hydraulic motor 10 by the speed reducer 11 to rotate a driving wheel 21 described later with a large torque, and the crawler belt 7 wound around the driving wheel 21 and the idler wheel 6. Is driven around.

  Reference numeral 11 denotes a reduction gear that reduces the rotation of the hydraulic motor 10, and the reduction gear 11 includes a stationary housing 12, a rotation housing 14, planetary gear reduction mechanisms 24 and 29, a floating seal 34, a closing ring 39, and the like, which will be described later. Has been.

  Reference numeral 12 denotes a fixed-side housing fixed to the traveling device bracket 9, and the fixed-side housing 12 is provided with a hydraulic motor 10 as a rotation source. Here, the fixed-side housing 12 has a large-diameter flange portion 12 </ b> A, and the flange portion 12 </ b> A is fixed to the traveling device bracket 9 using a plurality of bolts 13.

  Further, a male spline to which a housing support portion 12B for supporting a rotation side housing 14 to be described later and a carrier 33 of a planetary gear speed reduction mechanism 29 to be described later is coupled to the front end side of the fixed side housing 12 protruding from the traveling device bracket 9. A portion 12C is provided. In addition, a cylindrical seal mounting portion 12D to which a fixed-side seal ring 35 described later is attached is provided between the flange portion 12A and the housing support portion 12B, and a distal end portion of the seal mounting portion 12D is a flange described later. It is an annular facing surface 12E that faces the 15 facing surfaces 15B in the axial direction (see FIGS. 3 and 4).

  Reference numeral 14 denotes a rotation-side housing that is provided so as to be rotatable with respect to the fixed-side housing 12. The rotation-side housing 14 is formed in a covered cylindrical shape as a whole, and accommodates planetary gear reduction mechanisms 24 and 29 described later therein. To do. The rotation-side housing 14 has an annular flange 15 disposed on the outer peripheral side of the housing support portion 12B provided on the fixed-side housing 12, and is fixed to the flange 15 with bolts 16 and has internal teeth on the inner peripheral side. A cylindrical drum 17 on which 17A is formed and a disc-shaped lid 18 that covers the drum 17 are roughly configured.

  Here, the inner peripheral side of the flange 15 is rotatably attached to the housing support portion 12B of the fixed side housing 12 via a bearing 19, and a plurality of bolts 20 are used on the outer peripheral side of the flange 15 to drive wheels (sprockets). ) 21 is fixed. Further, the flange 15 is provided with a cylindrical seal mounting portion 15A to which a rotation side seal ring 36 to be described later is attached. As shown in FIGS. 3 and 4, the flange 15 is fixed to the inner peripheral side of the seal mounting portion 15A. An annular facing surface 15B that is opposed to the facing surface 12E of the side housing 12 in the axial direction is provided.

  Reference numeral 22 denotes an axial gap formed between the fixed housing 12 and the rotary housing 14, and the gap 22 rotates between the opposing surface 12E of the fixed housing 12 and the rotation as shown in FIGS. Between the opposing surface 15B of the flange 15 which comprises the side housing 14, it is formed cyclically | annularly over the perimeter. A floating seal 34 described later is provided inside the gap 22 in the radial direction, and a closing ring 39 described later is provided in the gap 22.

  Reference numeral 23 denotes a rotation shaft for deriving the rotation output of the hydraulic motor 10, the proximal end side of the rotation shaft 23 is connected to the output shaft of the hydraulic motor 10, and the distal end side of the rotation shaft 23 extends in the axial direction within the rotation side housing 14. It is stretched. A sun gear 25 described later is integrally formed at the tip of the rotating shaft 23 located in the vicinity of the lid 18.

  Reference numeral 24 denotes a first-stage planetary gear reduction mechanism housed in the rotation-side housing 14, and the planetary gear reduction mechanism 24 cooperates with a later-described second-stage planetary gear reduction mechanism 29 to rotate the hydraulic motor 10. The drive wheel 21 fixed to the flange 15 of the rotation side housing 14 is rotated with a large torque.

  Here, the planetary gear speed reduction mechanism 24 meshes with the sun gear 25 integrally formed at the tip of the rotating shaft 23 and the sun gear 25 and the internal teeth 17A of the drum 17 and rotates around the sun gear 25. A plurality of planetary gears 26 (only one is shown) that revolves while revolving, and a carrier 28 that rotatably supports the planetary gears 26 via pins 27 and the like. The planetary gear reduction mechanism 24 decelerates the rotation of the sun gear 25 and transmits the revolution of the planetary gear 26 to the second-stage sun gear 30 to be described later via the carrier 28.

  Reference numeral 29 denotes a second-stage planetary gear reduction mechanism housed in the rotation-side housing 14, and the planetary gear reduction mechanism 29 is splined to the first-stage carrier 28 while being loosely fitted to the rotation shaft 23. The sun gear 30 to which only the revolution of the first-stage planetary gear 26 is transmitted via the carrier 28 and the sun gear 30 and the internal teeth 17A of the drum 17 are meshed with each other and revolved while rotating around the sun gear 30. A plurality of planetary gears 31 (only one is shown) and a carrier 33 that rotatably supports the planetary gears 31 via pins 32 or the like.

  The carrier 33 is splined to the male spline portion 12 </ b> C of the stationary housing 12. Thereby, the revolution of the planetary gear 31 supported by the carrier 33 is transmitted to the rotation side housing 14 via the internal teeth 17A of the drum 17, and the rotation side housing 14 is two-staged by the planetary gear reduction mechanisms 24 and 29. It is configured to rotate with respect to the stationary housing 12 in a decelerated state.

  Here, the rotation side housing 14 is filled with lubricating oil L for lubricating the planetary gear speed reduction mechanisms 24 and 29, the bearing 19 and the like, and this lubricating oil L is rotated by a floating seal 34 which will be described later. It is configured to be sealed inside.

  34 is a floating seal provided radially inside a gap 22 formed between the stationary housing 12 and the rotating housing 14. The floating seal 34 seals the lubricating oil L in the rotating housing 14. In addition, foreign matter such as muddy water and earth and sand is prevented from entering the rotary housing 14. Here, as shown in FIGS. 3 and 4, the floating seal 34 includes a fixed-side seal ring 35, a rotation-side seal ring 36, a fixed-side O-ring 37, a rotation-side O-ring 38 and the like which will be described later.

  Reference numeral 35 denotes a fixed side seal ring positioned on the fixed side housing 12 side. The fixed side seal ring 35 is paired with a rotation side seal ring 36 which will be described later. For example, a metal material having excellent wear resistance and corrosion resistance is used. It is formed in a cylindrical shape and is disposed on the inner peripheral side of the seal mounting portion 12D provided in the stationary housing 12.

  Here, the fixed-side seal ring 35 is provided with a large-diameter flange portion 35A, and an annular slidable contact surface 35B is formed on the end surface of the large-diameter flange portion 35A so as to be located radially inside the gap 22. ing. Further, the outer peripheral surface 35C of the fixed side seal ring 35 facing the inner peripheral surface 12F of the seal mounting portion 12D becomes a tapered surface that gradually increases in diameter toward the large diameter flange portion 35A, and this outer peripheral surface 35C and the seal mounting portion Between the inner peripheral surface 12F of 12D, a fixed side O-ring 37 described later is provided.

  Reference numeral 36 denotes a rotation-side seal ring located on the rotation-side housing 14 side. The rotation-side seal ring 36 is composed of the same parts as the fixed-side seal ring 35, and a seal mounting portion 15 </ b> A provided on the flange 15 of the rotation-side housing 14. It is arranged on the inner circumference side.

  Here, the rotation-side seal ring 36 is provided with a large-diameter flange portion 36A, and the end surface of the large-diameter flange portion 36A is located on the radially inner side of the gap 22, and the sliding contact surface of the fixed-side seal ring 35 An annular sliding contact surface 36B is formed in fluid contact with 35B. Further, the outer peripheral surface 36C of the rotation side seal ring 36 facing the inner peripheral surface 15C of the seal mounting portion 15A becomes a tapered surface that gradually increases in diameter toward the large-diameter flange portion 36A, and this outer peripheral surface 36C and the seal mounting portion A rotation side O-ring 38 described later is provided between the inner peripheral surface 15C of 15A.

  Reference numeral 37 denotes a fixed-side O-ring provided between the inner peripheral surface 12E of the seal mounting portion 12D provided in the fixed-side housing 12 and the outer peripheral surface 35C of the fixed-side seal ring 35. It forms a pair with a rotation side O-ring 38, which will be described later, and is formed in a ring shape using a rubber material having oil resistance and elasticity such as butadiene rubber. The fixed-side O-ring 37 seals between the seal mounting portion 12D of the fixed-side housing 12 and the fixed-side seal ring 35, and always has the fixed-side seal ring 35 directed toward the rotation-side seal ring 36 in the axial direction. Press.

  Reference numeral 38 denotes a rotation-side O-ring that is provided axially away from the fixed-side O-ring 37, and the rotation-side O-ring 38 sandwiches the gap 22 with the fixed-side O-ring 37. It is provided between the inner peripheral surface 15 C of the seal mounting portion 15 A provided on the flange 15 of the rotation side housing 14 and the outer peripheral surface 36 C of the rotation side seal ring 36. The rotation-side O-ring 38 is made of the same components as the fixed-side O-ring 37, seals between the seal mounting portion 15A of the flange 15 and the rotation-side seal ring 36, and also fixes the rotation-side seal ring 36 to the fixed-side seal. It is always pressed toward the ring 35 in the axial direction.

  Accordingly, the sliding contact surface 35B of the fixed side seal ring 35 and the sliding contact surface 36B of the rotation side seal ring 36 are appropriately adjusted by the axial pressing force applied from the fixed side O ring 37 and the rotation side O ring 38. When the rotary housing 14 rotates with respect to the fixed housing 12, the lubricating oil L is sealed in the rotary housing 14 by sealing the two together in a liquid-tight manner.

  39 is a closing ring provided in the gap 22 between the stationary housing 12 and the rotating housing 14, and the closing ring 39 is provided in the stationary housing 12 as shown in FIGS. It is disposed in an axial gap 22 formed between the facing surface 12E of the seal mounting portion 12D and the facing surface 15B of the seal mounting portion 15A provided on the flange 15 constituting the rotation side housing 14, and the clearance 22 is closed.

  Here, the closing ring 39 is formed of an oil-containing closing ring that is formed in an annular shape having a quadrangular cross section using a polymer material such as ultra-high molecular weight polyethylene or polyolefin, and is impregnated with lubricating oil. In this case, the closing ring 39 has a shape corresponding to the annular gap 22 formed between the stationary housing 12 and the rotating housing 14, and the inner diameter of the closing ring 39 constitutes the floating seal 34. It is set to be larger than the outer diameter dimension of the sliding contact surfaces 35B and 36B provided on the seal rings 35 and 36, respectively.

  On the other hand, the closing ring 39 is composed of a self-lubricating closing ring formed using a resin material having self-lubricating properties, for example, a resin material such as polytetrafluoroethylene (PTFE), fiber reinforced nylon, polyacetal (POM), or the like. May be. In this case, since the self-lubricating blocking ring can be formed using a relatively inexpensive resin material, the manufacturing cost of the entire speed reduction device 11 is reduced by using the blocking ring formed of the self-lubricating blocking ring. can do.

  The closing ring 39 is located between the fixed side O-ring 37 and the rotary side O-ring 38 constituting the floating seal 34, and the sliding contact surface 35B of the fixed side seal ring 35 and the rotary side seal ring 36 are in sliding contact. In a state where the contact portion with the surface 36B is surrounded from the outside in the radial direction, the seal mounting provided on the opposing surface 12E of the seal mounting portion 12D provided on the stationary housing 12 and the rotating housing 14 (flange 15). It is sandwiched between the opposing surface 15B of the part 15A.

  When the excavator 1 travels, the closing ring 39 closes the gap 22 between the stationary housing 12 and the rotating housing 14 when the rotating housing 14 rotates with respect to the stationary housing 12. . Accordingly, the blocking ring 39 prevents foreign matters such as muddy water and earth and sand from entering the floating seal 34 from the gap 22 between the stationary housing 12 and the rotating housing 14, thereby protecting the floating seal 34. It has become.

  In this case, since the inside of the closing ring 39 is impregnated with lubricating oil, the closing ring 39 is attached to the seal mounting portion 12D of the stationary housing 12 and the seal mounting portion 15A of the flange 15 constituting the rotation side housing 14. Even if they come into sliding contact, the friction between the seal mounting portions 12D and 15A of the housings 12 and 14 and the closing ring 39 can be suppressed. Accordingly, the wear of the closing ring 39 can be suppressed and the life can be extended, and the rotation side housing 14 can be smoothly rotated with respect to the stationary side housing 12.

  The reduction gear 11 according to the present embodiment has the above-described configuration. When the hydraulic motor 10 is rotated while the hydraulic excavator 1 is traveling, the rotation of the hydraulic motor 10 causes the planetary gear reduction mechanisms 24 and 29 of the reduction gear 11 to rotate. Is reduced by two stages and transmitted to the rotation-side housing 14. As a result, the rotation-side housing 14 rotates with a large torque, the crawler belt 7 wound around the drive wheel 21 and the idler wheel 6 fixed to the rotation-side housing 14 is driven, and the excavator 1 travels.

  Here, the rotation-side seal ring 36 of the floating seal 34 rotates integrally with the rotation-side housing 14, and the rotation-side seal ring 36 is in sliding contact with the sliding contact surface 35 B of the fixed seal ring 35. By doing so, the space between the rotation-side housing 14 and the stationary-side housing 12 is sealed in a liquid-tight manner. As a result, the lubricating oil L is held in the rotating side housing 14, and the bearing 19, the planetary gear speed reduction mechanisms 24, 29, and the like can be properly lubricated by the lubricating oil L, so that the rotating side housing 14 rotates smoothly. Can be made.

  At this time, the closing ring 39 is located between the facing surface 12E of the seal mounting portion 12D provided in the stationary housing 12 and the facing surface 15B of the seal mounting portion 15A provided in the rotation side housing 14 (flange 15). The formed axial gap 22 is always closed. Thereby, for example, when the excavator 1 travels in a muddy ground, foreign matters such as muddy water and earth and sand enter the floating seal 34 through the gap 22 between the stationary housing 12 and the rotating housing 14. It can be reliably prevented by the closing ring 39.

  As a result, the sliding contact surface 35B of the stationary seal ring 35 and the sliding contact surface 36B of the rotation-side seal ring 36 constituting the floating seal 34 are damaged by intrusion of earth and sand or rust is generated by intrusion of muddy water. Can be prevented. Further, it is possible to prevent muddy water or the like from adhering to the fixed-side O-ring 37 and the rotation-side O-ring 38, and to suppress the elasticity of the respective O-rings 37 and 38 from being lowered due to freezing of muddy water or the like.

  As a result, the sliding contact surface 35B of the fixed side seal ring 35 and the sliding contact surface 36B of the rotation side seal ring 36 are always in proper sliding contact with each other, thereby ensuring the sealing performance of the floating seal 34 and the rotation side housing 14. The space between the stationary housing 12 and the stationary housing 12 can be liquid-tightly sealed over a long period of time. As a result, the lubricating oil L filled in the rotation-side housing 14 is prevented from leaking to the outside, and the bearing 19, the planetary gear reduction mechanisms 24, 29, and the like can be properly lubricated by the lubricating oil L. The side housing 14 can be smoothly rotated over a long period of time, and the reliability of the entire reduction gear 11 can be improved.

  On the other hand, since the closing ring 39 is impregnated with lubricating oil, even if the closing ring 39 is in sliding contact with the facing surface 12E of the stationary housing 12 and the facing surface 15B of the rotating housing 14, each of the facing rings Friction between the surfaces 12E and 15B and the closing ring 39 can be suppressed. Thereby, the wear of the closing ring 39 can be suppressed and the life thereof can be extended, and the rotating side housing 14 can be smoothly rotated with respect to the fixed side housing 12.

  Thus, according to the present embodiment, the space between the facing surface 12E of the seal mounting portion 12D provided on the fixed side housing 12 and the facing surface 15B of the seal mounting portion 15A provided on the flange 15 of the rotation side housing 14 is determined. By providing an annular closing ring 39 on the radially inner side of the gap 22 formed in this, the gap 22 can be closed by the closing ring 39.

  For this reason, for example, when the excavator 1 travels in a muddy ground, foreign matters such as muddy water and earth and sand enter the floating seal 34 through the gap 22 between the stationary housing 12 and the rotating housing 14. The blocking ring 39 can surely prevent it. Accordingly, the sliding contact surfaces 35B and 36B of the seal rings 35 and 36 constituting the floating seal 34 can be prevented from being damaged by the intrusion of earth and sand or the rusting by the intrusion of muddy water. It can suppress that the elasticity of each O-ring 37 and 38 which comprises 34 falls by freezing of muddy water.

  As a result, the sealing property of the floating seal 34 can be maintained appropriately, and the space between the rotating side housing 14 and the stationary side housing 12 can be sealed in a liquid-tight manner. Accordingly, sufficient lubricating oil L is secured in the rotating side housing 14, and the bearing 19, planetary gear speed reduction mechanisms 24, 29, etc. are properly lubricated by the lubricating oil L, so that the rotating side housing 14 is maintained over a long period of time. It can be rotated smoothly, and the reliability of the entire reduction gear 11 can be improved.

  In addition, since the closing ring 39 is impregnated with lubricating oil, even if the closing ring 39 is in sliding contact with the facing surface 12E of the stationary housing 12 and the facing surface 15B of the rotating housing 14, these facings Friction between the surfaces 12E and 15B and the closing ring 39 can be suppressed by the lubricating oil leached from the closing ring 39. Thereby, the wear of the closing ring 39 can be suppressed and the life thereof can be extended, and the rotating side housing 14 can be smoothly rotated with respect to the fixed side housing 12.

  In the above-described embodiment, the space between the facing surface 12E of the seal mounting portion 12D provided on the stationary housing 12 and the facing surface 15B of the seal mounting portion 15A provided on the flange 15 of the rotating housing 14 is described. A case where an annular closing ring 39 having a quadrangular cross section is provided in the gap 22 is illustrated. However, the present invention is not limited to this. For example, as in the modification shown in FIG. 5, a configuration in which a closing ring 41 having an annular shape with a T-shaped cross section may be used.

  Further, in the above-described embodiment, the closing ring 39 provided in the gap 22 between the stationary housing 12 and the rotating housing 14 is formed in a ring shape using a polymer material and is impregnated with lubricating oil. The case where it comprises with an oil-impregnated obstruction ring is illustrated. However, the present invention is not limited to this. For example, a metallic closing ring formed in a ring shape using a metal material such as sintered metal and impregnated with lubricating oil may be used.

  Further, in each of the above-described embodiments, the speed reducer 11 used in the traveling device 8 of the excavator 1 is described as an example. However, the present invention is not limited to this, and can also be applied to a reduction gear used for, for example, a rope winch mounted on a hydraulic crane.

1 is a front view showing a hydraulic excavator provided with a reduction gear according to a first embodiment of the present invention. It is sectional drawing which looked at the hydraulic motor of the lower traveling body, the reduction gear, the drive wheel, the crawler belt, etc. from the arrow II-II direction in FIG. FIG. 3 is an enlarged cross-sectional view of a main part showing an enlarged view of a stationary housing, a rotating housing, a floating seal, and a closing ring in FIG. It is a partially broken exploded perspective view showing a stationary side housing, a rotating side housing, a floating seal, and a closing ring. It is a principal part expanded sectional view similar to FIG. 3 which shows the modification of a closure ring.

Explanation of symbols

10 Hydraulic motor (rotation source)
DESCRIPTION OF SYMBOLS 11 Deceleration device 12 Fixed side housing 12E Opposite surface 12F Inner peripheral surface 14 Rotation side housing 15 Flange 15B Opposite surface 15C Inner peripheral surface 22 Gap 24, 29 Planetary gear reduction mechanism (deceleration mechanism)
34 Floating seal 35 Fixed side seal ring 35B, 36B Sliding contact surface 35C, 36C Outer peripheral surface 36 Rotation side seal ring 37 Fixed side O ring 38 Rotation side O ring 39, 41 Closure ring

Claims (3)

A fixed housing provided with a rotation source, a rotation housing provided rotatably with respect to the fixed housing, and driven by the rotation source, and a deceleration accommodated in the rotation side housing and decelerating the rotation of the rotation source In a speed reducer comprising a mechanism and a floating seal provided radially inward of the gap in order to seal an axial gap between the stationary housing and the rotating housing,
A reduction gear having a structure in which a gap between the stationary housing and the rotation housing is provided with an annular closing ring that closes the gap and prevents foreign matter from entering the floating seal. .   The said closure ring is comprised with the oil-impregnated closure ring formed using the polymer material, the oil-impregnated closure ring impregnated with the lubricating oil, or the resin material which has self-lubricating property. The speed reducer described in 1. The gap between the stationary housing and the rotating housing is formed in an annular shape between the facing surface of the stationary housing and the facing surface of the rotating housing that face each other,
The floating seal includes a pair of seal rings that are disposed radially inward of the gap and have sliding contact surfaces that are in sliding contact with each other, and one of the seal rings with the gap interposed therebetween, and the stationary housing. A pair of O-rings spaced apart in the axial direction between the other inner peripheral surface and between the other seal ring and the inner peripheral surface of the rotary housing,
3. The reduction gear according to claim 1, wherein the closing ring is positioned between the O-rings and arranged radially outside the sliding contact surface of the seal ring to close the gap.

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