JP2007002981A - Reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily prevent the lubricating oil from leaking even when a seal for sealing the lubricating oil is damaged in a housing. <P>SOLUTION: A notch groove 24 is provided in the sharp corner at the inner peripheral side of an projection 23 formed in the lower face side of a lower side housing 13 (a flange 13A) throughout the entire periphery. A rising wall 25B is provided in the outer peripheral side of a shield plate 25 disposed between a pinion 18 and a lower side bearing 20. A seal setting space 26 capable of setting an auxiliary seal 27 is formed between a peripheral wall 24A of the notch groove 24 and the rising wall 25B. Thereby, even when the lubricating oil in the housing 12 leaks through the oil seal 22 owing to the damage of the oil seal 22, for example, the lubricating oil can be prevented from leaking outside the housing 12 by setting the auxiliary seal 27 to a seal setting space 26 as a stopgap measure with the auxiliary seal 27. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  In general, construction machines such as a hydraulic excavator and a hydraulic crane are generally configured by a self-propelled lower traveling body and an upper revolving body that is rotatably mounted on the lower traveling body. A turning device for turning the upper turning body is provided between the lower traveling body and the upper turning body, and the turning device decelerates the rotation of a rotation source such as a hydraulic motor and increases torque. A reduction gear is provided.

  This conventional reduction device is usually a hollow housing in which a rotation source is provided on the upper end side and the lower end side is fixed to the upper swing body, a reduction mechanism provided in the housing for reducing the rotation of the rotation source, and the housing An output shaft extending in the upward and downward direction and outputting a rotation decelerated by the speed reduction mechanism, and an inner portion of the swivel wheel provided on the lower end side of the output shaft and disposed between the upper swing body and the lower traveling body. A pinion that meshes with the gear, an upper bearing and a lower bearing that rotatably support the output shaft, a seal that is located between the upper and lower bearings and is provided between the housing and the output shaft; An annular shielding plate provided between the bearing and the pinion is provided.

  The housing is filled with lubricating oil for lubricating the gears constituting the speed reduction mechanism, the upper bearing, and the like, and this lubricating oil is located between the upper and lower bearings and between the housing and the output shaft. It is sealed by a provided seal (oil seal).

  By the way, the meshing portion between the pinion and the internal gear of the swirling wheel is lubricated by the grease held in the grease bath, and this grease is a wear powder generated from the meshing portion of the pinion and the internal gear of the swirling wheel, It is known that it deteriorates at an early stage when water such as rainwater enters. For this reason, the speed reducer according to the prior art is provided with an annular shielding plate between the lower bearing and the pinion so that the deteriorated grease is pumped into the housing by the pump action when the internal gear and the pinion of the swirling wheel mesh. It is set as the structure which interrupts | blocks out (penetrating) to the side by a shielding board (for example, refer to cited reference 1).

JP 2003-156053 A

  By the way, in the above-described speed reduction device according to the prior art, when wear powder is generated from the meshing portions of the gears constituting the speed reduction mechanism during operation, the wear powder is mixed into the lubricating oil in the housing. The wear powder mixed in the lubricating oil adheres to the oil seal provided between the housing and the output shaft, and if this oil seal is damaged, the lubricating oil filled in the housing leaks to the outside. Therefore, there is a problem that the speed reduction mechanism and the like cannot be properly lubricated.

  On the other hand, when replacing a damaged oil seal to prevent leakage of the lubricating oil, it is necessary to disassemble the entire speed reducer, and it is necessary to replace this oil seal. There is a problem in that the oil seal replacement work itself is difficult at a work site where there are not enough tools.

  The present invention has been made in view of the above-described problems of the prior art, and provides a reduction gear that can easily suppress leakage of lubricating oil even when a seal that seals the lubricating oil in the housing is damaged. The purpose is to do.

  In order to solve the above-described problems, the present invention provides a hollow housing having a rotation source provided on the upper end side and a flange portion on which the lower end side is fixed to an attachment target, and rotation of the rotation source provided in the housing. A deceleration mechanism that decelerates, an output shaft that extends upward and downward in the housing and outputs rotation decelerated by the deceleration mechanism, a pinion that is provided on the lower end side of the output shaft and meshes with a gear, and the housing An upper bearing and a lower bearing that are spaced apart from each other in the upward and downward directions between the output shaft and rotatably support the output shaft; and the housing and the output that are positioned between the upper and lower bearings A seal provided between the shaft and sealing the lubricating oil in the housing; and a grease provided between the lower bearing and the pinion for lubricating a meshing portion of the pinion and the gear. It applied to the speed reduction device comprising a shielding plate for blocking the ingress within.

  A feature of the configuration adopted by the invention of claim 1 is that an annular protrusion having a diameter larger than that of the lower bearing is protruded downward on the lower surface side of the flange portion of the housing. A notch groove is provided in the corner corner on the circumferential side over the entire circumference, and the shielding plate is sandwiched between the lower bearing and the pinion and has a larger outer diameter than the outer ring of the lower bearing. And a rising wall portion rising upward from the outer peripheral side of the disc portion into the notch groove, and an auxiliary seal is attached between the peripheral wall of the notch groove and the rising wall portion of the shielding plate The seal mounting space that can be used is formed.

  According to a second aspect of the present invention, the lower surface of the projecting portion and the lower surface of the inner ring of the lower bearing are located on substantially the same plane, and the disk portion of the shielding plate is provided on the lower surface of the inner ring of the lower bearing and the pinion. The upper end of the rising wall portion rises to the vicinity of the upper wall of the notch groove.

  According to the first aspect of the present invention, a notch groove is provided over the entire circumference at the corners on the inner peripheral side of the protrusion provided on the housing, and a seal is provided between the peripheral wall of the notch groove and the rising wall portion of the shielding plate. Since the mounting space is formed, for example, even if the seal for sealing the lubricating oil in the housing is damaged, the auxiliary seal can be mounted as an emergency measure in the seal mounting space. Accordingly, the lubricating oil can be sealed in the housing by the auxiliary seal attached in the seal mounting space, and the lubricating oil in the housing can be prevented from flowing out to the outside. Accordingly, the speed reduction mechanism in the housing can be always properly lubricated with the lubricating oil, and the reliability of the speed reduction device can be improved.

  In this case, since the seal mounting space is provided in advance on the lower surface side of the flange portion constituting the lower end side of the housing, it is easy to mount the auxiliary seal in the seal mounting space without disassembling the entire reduction gear. Can be done. Accordingly, the auxiliary seal can be quickly attached even at a work site where tools and the like are not prepared, and the loss of lubricating oil can be suppressed.

  According to invention of Claim 2, the disc part of a shielding board is clamped between the lower surface of the inner ring | wheel of a lower side bearing, and the upper surface of a pinion, and the upper end of the rising wall part of a shielding board is from the outer peripheral side of a disc part. By rising up to the vicinity of the upper wall of the notch groove, the lower bearing can be reliably covered from below by the shielding plate. As a result, even when grease is spouted upward from the meshing portion of the pinion and the gear in the state where the auxiliary seal is not installed in the seal mounting space, this grease passes through the gap between the inner ring and the outer ring of the lower bearing. Intrusion into the housing can be reliably blocked by the shielding plate.

  Hereinafter, an embodiment of the speed reducer according to the present invention will be described in detail with reference to FIG. 1 to FIG.

  In the figure, reference numeral 1 denotes a hydraulic excavator. The hydraulic excavator 1 includes a self-propelled crawler-type lower traveling body 2 and an upper revolving body mounted on the lower traveling body 2 through a swirling wheel 3 so as to be capable of swiveling. 4 and a work device 5 that is provided on the front side of the upper swing body 4 so as to be able to be lifted and lowered and that performs excavation work such as earth and sand.

  Here, as shown in FIG. 2, the turning wheel 3 is fixed to an inner ring 3 </ b> A fixed on a round body 2 </ b> A constituting the lower traveling body 2 and a lower surface side of a turning frame 4 </ b> A constituting the upper turning body 4. The outer ring 3B and a plurality of steel balls 3C (only one is shown) disposed between the inner ring 3A and the outer ring 3B. An inner gear 3D as a gear that meshes with a pinion 18 to be described later is formed on the inner peripheral side of the inner ring 3A. The inner gear 3D and the pinion 18 are formed on the inner peripheral side of the inner gear 3D. A grease bath 6 that contains grease (not shown) that lubricates the meshing portion is provided.

  Reference numeral 7 denotes a turning device for turning the upper turning body 4 on the lower traveling body 2. The turning device 7 decelerates the rotation of the hydraulic motor 8 as a rotation source and the motor shaft 8A of the hydraulic motor 8, and turns the turning wheel. 3 is composed mainly of a later-described speed reducer 11 that transmits a large rotational force (torque) to 3. And this reduction gear 11 is being fixed to the turning frame 4A as an attachment target object using the some volt | bolt 9. As shown in FIG.

  Reference numeral 11 denotes a speed reducer that decelerates the rotation of the hydraulic motor 8 (motor shaft 8A). The speed reducer 11 includes a housing 12, planetary gear speed reduction mechanisms 15 and 16, an output shaft 17, an upper bearing 19, and a lower bearing 20 described later. , An oil seal 22, a projection 23, a shielding plate 25, a seal mounting space 26, and the like.

  Reference numeral 12 denotes a hollow housing that forms the outer shell of the speed reducer 11, and the housing 12 is a stepped cylindrical lower housing fixed on the swivel frame 4A using a plurality of bolts 9 as shown in FIG. 13 and a cylindrical upper housing 14 fixed on the lower housing 13 with bolts and having a hydraulic motor 8 attached to the upper end side thereof, is formed in a cylindrical shape extending upward and downward.

  Here, the lower end side of the lower housing 13 is a large-diameter disk-shaped flange portion 13A, and a plurality of bolt insertion holes 13B (only two are shown) are spaced in the circumferential direction on the outer peripheral side of the flange portion 13A. Are arranged in a ring shape. The housing 12 is fixed on the turning frame 4A by screwing the bolts 9 inserted into the bolt insertion holes 13B into the turning frame 4A. Further, on the lower surface side of the flange portion 13A, a projection 23 described later is provided so as to protrude downward from the bolt insertion hole 13B in the radial direction.

  Further, on the inner peripheral side of the lower housing 13, an upper bearing mounting portion 13C to which an upper bearing 19 described later is mounted and a lower bearing mounting portion 13D to which a lower bearing 20 described later is mounted are upward and downward. They are spaced apart. Further, between these upper and lower bearing mounting portions 13C and 13D, a seal mounting portion 13E to which an oil seal 22 described later is mounted is provided.

  On the other hand, a hydraulic motor 8 is attached to the upper end side of the upper housing 14, and a motor shaft 8 </ b> A of the hydraulic motor 8 extends into the upper housing 14. Further, on the inner peripheral side of the upper housing 14, upper inner teeth 14A that mesh with a planetary gear 15B described later and lower inner teeth 14B that engage with a planetary gear 16B described later are formed over the entire circumference. ing.

  Reference numeral 15 denotes a first stage planetary gear speed reduction mechanism provided in the housing 12 below the hydraulic motor 8. The planetary gear speed reduction mechanism 15 is a sun spline-coupled to the motor shaft 8 A of the hydraulic motor 8. A plurality of planetary gears 15B (only one shown) meshing with the gear 15A, the sun gear 15A and the upper internal teeth 14A of the upper housing 14 and revolving around the sun gear 15A, and the planetary gears The carrier 15C is configured to rotatably support 15B.

  Reference numeral 16 denotes a second-stage planetary gear reduction mechanism located in the housing 12 below the planetary gear reduction mechanism 15, and the planetary gear reduction mechanism 16 is splined to the carrier 15 </ b> C of the planetary gear reduction mechanism 15. A plurality of planetary gears 16B (only one is shown) that meshes with the sun gear 16A and the sun gear 16A and the lower inner teeth 14B of the upper housing 14 and revolves around the sun gear 16A. Each planetary gear 16B is constituted by a carrier 16C that rotatably supports the planetary gears 16B.

  Reference numeral 17 denotes an output shaft provided in the housing 12 so as to extend upward and downward. The output shaft 17 is rotatably supported by the lower housing 13 via an upper bearing 19 and a lower bearing 20 described later. Yes. The output shaft 17 outputs the rotation of the hydraulic motor 8 (motor shaft 8A) decelerated by two stages by the planetary gear speed reduction mechanisms 15 and 16.

  Here, a male spline (shaft spline) 17A to which the carrier 16C of the planetary gear speed reduction mechanism 16 is splined is formed on the upper end side of the output shaft 17, and a nut member described later is formed on the lower side of the male spline 17A. A male screw portion 17B to which 21 is screwed is formed.

  Reference numeral 18 denotes a pinion integrally provided on the lower end side of the output shaft 17. The pinion 18 protrudes downward from the lower end side of the housing 12 (lower housing 13) and meshes with the internal gear 3 </ b> D of the swivel wheel 3. . The pinion 18 transmits the rotation of the output shaft 17 to the turning wheel 3 (inner wheel 3A).

  Reference numeral 19 denotes an upper bearing provided between the lower housing 13 and the output shaft 17. As shown in FIG. 3 and the like, the upper bearing 19 is a tapered roller bearing and is connected to the upper bearing mounting portion 13 </ b> C of the lower housing 13. The outer ring 19A is fitted, an inner ring 19B fitted and fixed to the output shaft 17, and a plurality of substantially conical rolling elements 19C provided between the outer ring 19A and the inner ring 19B.

  Reference numeral 20 denotes a lower bearing which is located below the upper bearing 19 and is provided between the lower housing 13 and the output shaft 17. The lower bearing 20 is a tapered roller bearing similar to the upper bearing 19. The outer ring 20A fitted to the lower bearing mounting portion 13D, the inner ring 20B fitted and fixed to the output shaft 17, and a plurality of substantially conical rolling rollers provided between the outer ring 20A and the inner ring 20B. It is comprised by the moving body 20C.

  The upper bearing 19 and the lower bearing 20 support the output shaft 17 so as to be rotatable with respect to the housing 12 while being appropriately pressurized in the axial direction by a nut member 21 described later.

  Reference numeral 21 denotes a nut member positioned below the planetary gear speed reduction mechanism 16 and screwed to the male screw portion 17B of the output shaft 17, and the nut member 21 is screwed to the male screw portion 17B of the output shaft 17. The lower surface is brought into contact with the inner ring 19B of the upper bearing 19, and the upper bearing 19 and the lower bearing 20 are appropriately pressurized in the axial direction.

  22 is an oil seal provided between the upper bearing 19 and the lower bearing 20 and provided between the lower housing 13 and the output shaft 17, and the oil seal 22 is, as shown in FIG. It is generally constituted by a cored bar 22A formed in an annular shape with an L-shaped cross-sectional shape, and a lip part 22B made of a rubber material or the like fixed to the cored bar 22A by means of baking or the like.

  The oil seal 22 is inserted into the housing 12 by fitting the metal core 22A to the seal mounting portion 13E of the lower housing 13 and sliding the lip portion 22B to the outer peripheral surface of the output shaft 17 with appropriate elasticity. Seals the lubricating oil. The planetary gear reduction mechanisms 15 and 16, the upper bearing 19, and the like can be constantly lubricated by the lubricating oil sealed in the housing 12 by the oil seal 22.

  23 is a protrusion provided on the lower surface side of the flange portion 13A of the lower housing 13, and the protrusion 23 has an annular shape larger than that of the lower bearing 20 as shown in FIG. The 20 outer rings 20A protrude downward in a state of being surrounded from the outer peripheral side over the entire circumference. Here, the lower surface 23 </ b> A of the protruding portion 23 is positioned on substantially the same plane AA as the lower surface 20 </ b> D of the inner ring 20 </ b> B constituting the lower bearing 20.

  24 is a notch groove provided at a corner on the inner peripheral side of the projecting portion 23, and the notch groove 24 is formed by notching the corner corner on the inner peripheral side of the projecting portion 23 over the entire circumference, thereby And an inner portion are formed as an annular groove, and are constituted by a peripheral wall 24A surrounding the lower bearing 20 from the outer peripheral side and an upper wall 24B closing the upper end side of the peripheral wall 24A. And in the notch groove 24, it becomes the structure by which the rising wall part 25B of the shielding board 25 mentioned later is arrange | positioned.

  Reference numeral 25 denotes an annular shielding plate provided between the pinion 18 and the lower bearing 20, and the shielding plate 25 has a larger outer diameter than the outer ring 20A of the lower bearing 20, as shown in FIG. A flat disk portion 25A having the output shaft 17 inserted in the center thereof, and a cylindrical shape which is bent vertically upward from the outer peripheral side of the disk portion 25A and rises into the notch groove 24. It is integrally formed with the rising wall portion 25B.

  Here, in the state where the central portion of the disc portion 25A is inserted into the output shaft 17, the shielding plate 25 has an inner peripheral side of the disc portion 25A on the upper surface 18A of the pinion 18 and a lower surface 20D of the inner ring 20B of the lower bearing 20. The rising wall portion 25B of the shielding plate 25 rises into the cutout groove 24 and faces the peripheral wall 24A of the cutout groove 24 over the entire circumference. Further, the upper end portion 25C of the rising wall portion 25B rises to the vicinity of the upper wall 24B of the notch groove 24 and faces the upper wall 24B with a slight gap.

  The shielding plate 25 rotates integrally with the pinion 18 with the lower bearing 20 covered from the lower side over the entire circumference, and lubricates the meshing portion between the internal gear 3D and the pinion 18 of the swivel wheel 3. This prevents the grease from entering the housing 12 through the gap between the outer ring 20A and the inner ring 20B of the lower bearing 20 when jetted upward from the meshing portion.

  Reference numeral 26 denotes a seal mounting space formed between the peripheral wall 24A of the notch groove 24 and the rising wall portion 25B of the shielding plate 25. The seal mounting space 26 extends around the rising wall portion 25B of the shielding plate 25 over the entire circumference. It is formed as an annular space surrounding from the outer peripheral side. The seal mounting space 26 is provided with an auxiliary seal 27 described later as an emergency measure when there is a possibility that the lubricating oil leaks to the outside (downward) of the housing 12 due to, for example, damage to the oil seal 22.

  Reference numeral 27 denotes an auxiliary seal attached to the seal attachment space 26. As shown in FIGS. 4 and 5, the auxiliary seal 27 is an oil seal similar to the oil seal 22, and is formed in an annular shape with an L-shaped cross-sectional shape. The core bar 27A and a lip portion 27B made of a rubber material or the like fixed to the core bar 27A by means of baking or the like are roughly constituted.

  The auxiliary seal 27 is fitted to the peripheral wall 24A of the cutout groove 24 and the lip portion 27B is slidably contacted with the rising wall portion 25B of the shielding plate 25 with appropriate elasticity. The space between the wall portion 25B and the wall portion 25B is liquid-tightly sealed. Therefore, for example, even if the oil seal 22 is damaged and the lubricating oil in the housing 12 leaks downward through the oil seal 22, as shown in FIG. 5, the auxiliary seal 27 is provided in the seal mounting space 26 as an emergency measure. By being attached, the lubricant can be prevented from flowing out of the housing 12.

  The reduction gear 11 according to the present embodiment has the above-described configuration. When the motor shaft 8A of the hydraulic motor 8 rotates, the rotation of the motor shaft 8A is reduced by two stages by the planetary gear reduction mechanisms 15 and 16 and output. The pinion 18 is transmitted to the shaft 17 and rotates with a large rotational force (torque).

  Then, the pinion 18 revolves along the inner ring 3A while meshing with the internal gear 3D provided on the inner ring 3A of the turning wheel 3, and the revolution force of the pinion 18 is transmitted to the turning frame 4A via the housing 12, thereby turning. The frame 4A (upper rotating body 4) rotates on the round body 2A (lower traveling body 2).

  Here, during the operation of the speed reducer 11 described above, the planetary gears 15B of the planetary gear speed reduction mechanism 15 are caused by wear particles generated when the planetary gears 15B mesh with the sun gear 15A and the upper inner teeth 14A of the upper housing 14, and the planetary gear speed reduction mechanism 16 Wear particles generated by the planetary gears 16B meshing with the sun gear 16A and the lower inner teeth 14B of the upper housing 14 are mixed in the lubricating oil filled in the housing 12.

  Here, when the abrasion powder mixed in the lubricating oil settles down due to its own weight and adheres to the slidable contact portion between the lip portion 22B of the oil seal 22 and the output shaft 17, the lip portion 22B of the oil seal 22 It wears out early and becomes damaged. When the oil seal 22 is damaged and the sealing performance is impaired, the lubricating oil filled in the housing 12 leaks downward through the oil seal 22, thereby causing the planetary gear speed reduction mechanisms 15 and 16, the upper bearings. Lubrication to 19 etc. cannot be performed properly.

  Thus, when there is a possibility that the lubricating oil in the housing 12 may leak due to the damage of the oil seal 22, first, as shown in FIG. 4, the housing 12 (lower housing 13) of the speed reducer 11 is moved to the turning frame. Remove from 4A and lift the entire swivel device 7.

  In this state, the auxiliary seal 27 is inserted into the pinion 18 from below, the core metal 27A of the auxiliary seal 27 is fitted into the peripheral wall 24A of the notch groove 24, and the lip portion 27B is fitted to the rising wall portion 25B of the shielding plate 25. Make sliding contact with moderate elasticity. Thereby, between the rising wall part 25B of the shielding board 25 clamped between the pinion 18 and the lower side bearing 20, and the surrounding wall 24A of the notch groove 24 provided in the lower surface side of the housing 12 (lower side housing 13). Can be sealed liquid-tightly by the auxiliary seal 27.

  After the auxiliary seal 27 is mounted in the seal mounting space 26, as shown in FIG. 5, the lower housing 13 is fixed to the turning frame 4A by using the bolt 9, so that the auxiliary seal 27 leaks the lubricating oil. The speed reducer 11 subjected to the emergency treatment can be quickly attached to the turning frame 4 </ b> A, and the turning operation of the upper turning body 4 can be performed by the turning device 7.

  Thus, according to the present embodiment, the notch grooves 24 are provided over the entire circumference at the corners on the inner peripheral side of the protrusion 23 provided on the lower surface side of the lower housing 13 (flange portion 13A). A rising wall 25B is provided on the outer peripheral side of the shielding plate 25 sandwiched between the lower bearing 20 and a seal capable of attaching an auxiliary seal 27 between the peripheral wall 24A of the notch groove 24 and the rising wall 25B. The mounting space 26 is formed.

  Thus, for example, even if the oil seal 22 is damaged and the lubricating oil in the housing 12 leaks downward through the oil seal 22, the auxiliary seal 27 is attached to the seal mounting space 26 as an emergency measure. 27 prevents the lubricating oil from leaking to the outside of the housing 12. As a result, an appropriate amount of lubricating oil can be held in the housing 12, and the planetary gear speed reduction mechanisms 15, 16 and the upper bearing 19 can be properly lubricated by this lubricating oil. Stable operation can be ensured and its reliability can be improved.

  Therefore, for example, there is no need to perform complicated replacement work such as disassembling the speed reducer 11 and replacing the damaged oil seal 22 with a new one, and the seal mounting space 26 provided in advance on the lower surface side of the housing 12 is assisted. Since only the seal 27 is attached, leakage of the lubricating oil from the housing 12 can be suppressed, so that the workability can be improved.

  Moreover, since the seal mounting space 26 is formed on the lower surface side of the housing 12, the housing of the speed reducer 11 can be used even when lubricating oil leaks due to damage to the oil seal 22 at a work site where tools and the like are not prepared. The auxiliary seal 27 can be quickly mounted in the seal mounting space 26 formed on the lower surface side of the housing 12 simply by removing the 12 from the turning frame 4A. As a result, the loss of lubricating oil to the outside of the housing 12 can be minimized.

  Further, in the present embodiment, the lower surface 23A of the projecting portion 23 protruding from the lower surface side of the lower housing 13 and the lower surface 20D of the inner ring 20B of the lower bearing 20 are located on substantially the same plane AA. The disc portion 25A of the shielding plate 25 is sandwiched between the lower surface 20D of the inner ring 20B and the upper surface 18A of the pinion 18, and the upper end portion 25C of the rising wall portion 25B of the shielding plate 25 is formed on the upper wall 24B of the notch groove 24. It rises to the vicinity and faces the upper wall 24B with a slight gap.

  Thereby, since the lower bearing 20 can be reliably covered over the entire circumference from below by the shielding plate 25, the internal gear 3 </ b> D of the swivel wheel 3 can be used in a state where the auxiliary seal 27 is not attached to the seal attachment space 26. Even if the grease is ejected upward from the meshing portion with the pinion 18, the shielding plate 25 ensures that this grease enters the housing 12 through the gap between the outer ring 20 </ b> A and the inner ring 20 </ b> B of the lower bearing 20. The lubricating oil in the housing 12 can be kept clean.

  In the above-described embodiment, the case where the rising wall portion 25B is integrally formed on the outer peripheral side of the shielding plate 25 by bending the outer peripheral side of the disc portion 25A constituting the shielding plate 25 vertically upward is illustrated. ing. However, the present invention is not limited to this. For example, a cylindrical body made of a member different from the shielding plate 25 may be formed, and this cylindrical body may be fitted and fixed to the outer periphery of the disc portion 25A.

  In the above-described embodiment, the case where the two-stage planetary gear reduction mechanisms 15 and 16 are provided in the housing 12 is illustrated. However, the present invention is not limited to this. For example, a single-stage planetary gear reduction mechanism or a three-stage or higher planetary gear reduction mechanism may be provided.

  Furthermore, in the above-described embodiment, the case where the present invention is applied to the turning device 7 of the excavator 1 has been described as an example. However, the present invention is not limited to this, and for example, a turning device for other construction machines such as a hydraulic crane, The present invention may be applied to various reduction gears used in addition to the turning device.

1 is a front view showing a hydraulic excavator to which a reduction gear according to an embodiment of the present invention is applied. It is a longitudinal cross-sectional view which shows the reduction gear device by embodiment. It is an expanded sectional view which expands and shows principal parts, such as a lower bearing in FIG. 2, a notch groove, a shielding board, and a seal attachment space. It is sectional drawing which shows the state which attaches an auxiliary seal to seal installation space. It is an expanded sectional view similar to FIG. 3 which shows the state which attached the auxiliary seal to the seal attachment space.

Explanation of symbols

3D internal gear (gear)
4A swivel frame (object to be mounted)
8 Hydraulic motor (rotation source)
DESCRIPTION OF SYMBOLS 11 Deceleration device 12 Housing 13 Lower housing 13A Flange part 15, 16 Planetary gear reduction mechanism (deceleration mechanism)
17 Output shaft 18 Pinion 19 Upper bearing 20 Lower bearing 20A Outer ring 20B Inner ring 22 Oil seal (seal)
23 Projection 24 Notch Groove 24A Peripheral Wall 24B Top Wall 25 Shielding Plate 25A Disc Part 25B Rising Wall Part 26 Seal Installation Space 27 Auxiliary Seal

Claims (2)

A hollow housing provided with a rotation source at the upper end side and a flange portion with the lower end side fixed to the object to be mounted, a reduction mechanism provided in the housing for reducing the rotation speed of the rotation source, and an upper portion in the housing. , An output shaft extending downward and outputting a rotation decelerated by the speed reduction mechanism, a pinion provided on the lower end side of the output shaft and meshing with a gear, and an upward and downward direction between the housing and the output shaft An upper bearing and a lower bearing that are provided apart from each other and rotatably support the output shaft, and are located between the upper and lower bearings and provided between the housing and the output shaft. A seal that seals the lubricating oil, and a shielding plate that is provided between the lower bearing and the pinion and blocks grease that lubricates the meshing portion between the pinion and the gear from entering the housing. In Ete made the reduction gear,
On the lower surface side of the flange portion of the housing, an annular protrusion having a diameter larger than that of the lower bearing is protruded downward,
A notch groove is provided over the entire circumference at the corners on the inner peripheral side of the protrusion,
The shielding plate is sandwiched between the lower bearing and the pinion and has a disc portion having a larger outer diameter than the outer ring of the lower bearing, and upward from the outer peripheral side of the disc portion into the notch groove And a rising wall that rises
A speed reducer comprising a seal mounting space in which an auxiliary seal can be mounted between a peripheral wall of the notch groove and a rising wall portion of the shielding plate.   The lower surface of the protrusion and the lower surface of the inner ring of the lower bearing are located on the same plane, and the disc portion of the shielding plate is sandwiched between the lower surface of the inner ring of the lower bearing and the upper surface of the pinion. The speed reducer according to claim 1, wherein an upper end of the rising wall portion rises up to a vicinity of an upper wall of the notch groove.

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