Seal device and construction machine

Abstract

To provide a seal device having high seal performance and durability and reducible in size, and a construction machine.SOLUTION: A seal device 70 of an embodiment comprises: an output part 13 having an internal peripheral face 17b; a cover 60 rotating with respect to the output part 13 and oppositely arranged at the output part 13 in an axial direction; a seal ring 71 having a tapered external peripheral face 73a opposing the internal peripheral face 17b with an interval in a radial direction and having a seal face 74b which contacts with the cover 60 so as to be slidable thereto; and an O-ring 72 arranged between the internal peripheral face 17b and the tapered external peripheral face 73a. The seal face 74b is push-pressed toward the cover 60 by the O-ring 72, and a clearance between the seal face 74b and the cover 60 is sealed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a sealing device and a construction machine. [Background technology]

[0002] Construction machines such as bulldozers and hydraulic excavators are used in harsh environments. For this reason, a seal device with high sealing performance and durability is used in the moving parts of the construction machines to prevent the intrusion of foreign objects such as soil and sand and the leakage of lubricating oil. For example, a floating seal device is known as this type of seal device. The floating seal device includes a pair of seal rings that seal between a first member and a second member that rotate relative to each other, and an O-ring provided on the outer circumferential surface of each seal ring.

[0003] Each member is formed with a recess or the like for accommodating a seal ring. The seal rings are arranged on the inner circumferential surface of each member with a radial gap between them. The seal surfaces of the seal rings accommodated in each member are butted against each other. The seal surfaces slide against each other. The O-ring is sandwiched between the inner peripheral surface of each member and the outer peripheral surface of the seal ring. The outer peripheral surface of the seal ring is formed with an inclination. Therefore, the seal surfaces of the pair of seal rings are pressed against each other by the O-ring. This creates a seal between the first member and the second member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6453880 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the floating seal device requires that each member house a seal ring, which causes the seal device to become large in size.

[0006] The present invention provides a sealing device and a construction machine that have high sealing performance and durability and can be made compact. [Means for solving the problem]

[0007] A sealing device according to one embodiment of the present invention comprises a first member having an inner circumferential surface, a second member which rotates relative to the first member and is arranged opposite the first member in the direction of the rotation axis, a seal ring which has an outer circumferential surface which faces the inner circumferential surface in the radial direction with a gap therebetween and has a seal surface which comes into sliding contact with the second member, and an elastic ring which is arranged between the inner circumferential surface of the first member and the outer circumferential surface of the seal ring and which elastically deforms, wherein the elastic ring presses the seal surface of the seal ring towards the second member, thereby sealing between the seal surface and the second member.

[0008] With this configuration, it is possible to configure the seal device with a single seal ring, which ensures high sealing performance and durability of the seal device while also enabling it to be made compact.

[0009] In the above configuration, the first member may be formed in a cylindrical shape having an opening, and may include a third member housed within the first member and rotatably arranged relative to the first member, and the second member may be a cover provided at an end of the third member in the direction of the rotation axis and closing the opening of the first member.

[0010] In the above configuration, the first member and the third member may be rotatable relative to each other via a bearing, and the seal ring and the elastic ring may be arranged side by side in a radial direction perpendicular to the rotation axis with respect to the bearing.

[0011] In the above configuration, the first member and the third member may be connected via a speed change mechanism, and rotation of either the first member or the third member may be transmitted to the other of the first member or the third member at a changed speed.

[0012] In the above configuration, the second member is formed in a cylindrical shape having an opening, and is provided with a third member stored within the second member and arranged to be freely rotatable relative to the second member, the first member is a cover arranged at an end of the third member in the direction of the rotation axis and closes the opening of the second member, and the sealing surface may be pressed against the end of the second member in the direction of the rotation axis.

[0013] In the above configuration, the second member and the third member may be relatively rotatable via a bearing, and the seal ring and the elastic ring may be arranged side by side in a radial direction perpendicular to the rotation axis with respect to the bearing.

[0014] In the above configuration, the second member and the third member may be connected via a speed change mechanism, and rotation of either the second member or the third member may be transmitted to the other of the second member or the third member at a changed speed.

[0015] A construction machine according to another aspect of the present invention comprises a vehicle body having an operating part provided with a sealing device, the sealing device comprising: a first member having an inner circumferential surface shared with a part of the operating part; a second member which rotates relative to the first member and is arranged opposite the first member in the direction of the rotation axis and is shared with a part of the operating part; a seal ring having an outer circumferential surface facing the inner circumferential surface in the radial direction with a gap therebetween and having a sealing surface that comes into sliding contact with the second member; and an elastic ring which is arranged between the inner circumferential surface of the first member and the outer circumferential surface of the seal ring and elastically deforms, the elastic ring pressing the sealing surface of the seal ring towards the second member to seal between the sealing surface and the second member.

[0016] With this configuration, it is possible to configure the seal device with a single seal ring. This ensures high sealing performance and durability of the seal device, while also allowing for miniaturization. As a result, a highly functional construction machine can be provided. Effect of the Invention

[0017] The above-mentioned sealing device and construction machine have high sealing performance and durability, and can be made compact. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic configuration diagram of a shovel according to an embodiment of the present invention, viewed from the side. [Diagram 2] FIG. 2 is a cross-sectional view of a drive device according to an embodiment of the present invention. [Diagram 3] FIG. 3 is an enlarged view of part III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view of a sealing device according to a first modified example of the present invention. [Diagram 5] FIG. 11 is a cross-sectional view of a speed reducer portion in a second modified example of the present invention. [Figure 6] FIG. 11 is a cross-sectional view of a speed reducer portion in a third modified example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Next, an embodiment of the present invention will be described with reference to the drawings.

[0020] <Shovel> FIG. 1 is a schematic diagram of a shovel 100 according to an embodiment of a construction machine of the present invention, viewed from the side. In the following description, the front, which an operator (not shown) who operates the shovel 100 faces, is simply referred to as the front. The side horizontally opposite the front is referred to as the rear. The up-down direction when the shovel 100 is placed on the road surface is simply referred to as the up-down direction. The direction perpendicular to the fore-aft direction and the up-down direction is referred to as the vehicle width direction. FIG. 1 shows the shovel 100 as viewed from the vehicle width direction.

[0021] As shown in FIG. 1, the excavator 100 comprises a self-propelled running body 101, a rotating body 103 provided on the upper part of the running body 101 via a rotating mechanism 102, and an action unit 104 provided on the rotating body 103. The running body 101 and the turning mechanism 102 are driven by, for example, an electric motor with a reduction gear (not shown). The running body 101 includes, for example, two caterpillars 105 arranged in the vehicle width direction. However, this is not limited to this, and wheels or the like may be used instead of the caterpillars 105. The turning body 103 turns with respect to the running body 101.

[0022] The action unit 104 includes a boom 108 and an arm 109 that are long in the front-rear direction, and a bucket 110 attached to the arm 109. The boom 108, the arm 109, and the bucket 110 are rotatably connected via a drive unit 1. Specifically, one end (not shown) of the boom 108 on the side of the revolving body 103 in the longitudinal direction is rotatably connected to the revolving body 103 via the drive unit 1. In Fig. 1, the drive unit 1 provided at one end of the boom 108 is not shown.

[0023] One end 109a in the longitudinal direction of an arm 109 is rotatably connected to the other end 108a opposite to the one end in the longitudinal direction of the boom 108 via a driving device 1. A bucket 110 is rotatably connected to the other end 109b opposite to the one end 109a in the longitudinal direction of the arm 109 via the driving device 1. The driving devices 1 provided in each section have the same configuration. Therefore, in the following description, only the driving device 1 that connects one end 109a of the arm 109 to the other end 108a of the boom 108 will be described, and descriptions of the other driving devices 1 will be omitted.

[0024] <Drive unit> FIG. 2 is a cross-sectional view of the drive device 1. As shown in FIG. 2, the driving device 1 includes a motor unit 2 fixed to the other end 108 a of the boom 108 , and a speed reducer unit 3 connected to the motor unit 2 and fixed to one end 109 a of the arm 109 .

[0025] <Motor section> The motor section 2 includes a motor case 4 fixed to the boom 108, a cylindrical stator 5 housed in the motor case 4, and a rotor 6 provided radially inside the stator 5. The stator 5 includes a cylindrical stator core 7 and a coil 8 wound around the stator core 7. The outer peripheral surface of the stator core 7 is fitted and fixed to the inner peripheral surface of the motor case 4. The rotor 6 includes a rotor shaft 10 rotatably supported by the motor case 4 via bearings 9a and 9b, and a rotor core 11 fitted and fixed to the outer circumferential surface of the rotor shaft 10. The rotor core 11 is provided with a magnet (not shown).

[0026] With this configuration, when current is applied to the coil 8, a magnetic flux linkage is generated in the stator 5. A magnetic attraction force and a magnetic repulsion force are generated between this magnetic flux linkage and the magnet of the rotor 6. This causes the rotor core 11 and the rotor shaft 10 to rotate continuously as one unit. The rotor rotation axis A1 of the rotor shaft 10 coincides with the rotation axis of the arm 109 relative to the boom 108. In the following description, the direction parallel to the rotor rotation axis A1 is referred to as the axial direction, the rotation direction of the rotor 6 is referred to as the circumferential direction, and the radial direction of the rotor 6 perpendicular to the axial and circumferential directions is simply referred to as the radial direction.

[0027] <Deceleration part> The reduction section 3 comprises a fixed section (an example of the third member in the claims) 12 fixed to the motor case 4, a cylindrical output section (an example of the first member in the claims) 13 arranged to surround the fixed section 12 and supported for free rotation relative to the fixed section 12, a reduction mechanism 14 connected to the rotor shaft 10, and a sealing device 70 provided on the fixed section 12 and the output section 13. The central axis of the output part 13 coincides with the rotor rotation axis A1. An outer flange part 15 that protrudes radially outward is integrally formed on an outer peripheral surface 13a of the output part 13. One end 109a of an arm 109 is fixed to the outer flange part 15.

[0028] The output section 13 has seal accommodating recesses 16, 17 (first seal accommodating recess 16, second seal accommodating recess 17) formed on the axially outer side thereof. The seal accommodating recesses 16, 17 are formed by making the diameter of each of the seal accommodating recesses 16, 17 larger than the diameter of the inner peripheral surface 13b of the output section 13 via step portions 16a, 17a. The axially outer side of each of the seal accommodating recesses 16, 17 is open. In other words, the output section 13 has openings 13d, 13e (first opening 13d, second opening 13e) formed on the axially outer side thereof. The inner peripheral surfaces 16b, 17b of each of the seal accommodating recesses 16, 17 are inclined so that the inner diameter gradually increases toward the axially outer side.

[0029] Of the seal accommodating recesses 16, 17, a first floating seal 18a is provided in the first seal accommodating recess 16 on the motor section 2 side. Of the seal accommodating recesses 16, 17, a second floating seal 18b is provided in the second seal accommodating recess 17 on the opposite side to the motor section 2. The second floating seal 18b constitutes a seal device 70. The configuration of each of the floating seals 18a, 18b will be described in detail later.

[0030] A plurality of internal teeth 19 are provided on the inner circumferential surface 13b of the output portion 13. The internal teeth 19 are pin-shaped (cylindrical) teeth provided on the inner circumferential surface 13b of the output portion 13. The multiple internal teeth 19 are arranged over most of the axial center of the inner circumferential surface 13b. The multiple internal teeth 19 are arranged at equal intervals in the circumferential direction.

[0031] Bearing housings 21, 22 are integrally formed radially inward of each seal housing recess 16, 17 and axially outward of the internal teeth 19. Each bearing housing 21, 22 protrudes axially outward from the corresponding step portion 16a, 17a. Each bearing housing 21, 22 is formed in a cylindrical shape centered on the rotor rotation axis A1. Each bearing housing 21, 22 is provided with a bearing 23a, 23b (first bearing 23a, second bearing 23b).

[0032] That is, of the bearings 23a, 23b, the first bearing 23a arranged on the motor section 2 side is arranged radially side by side with the first floating seal 18a arranged on the motor section 2 side of the output section 13. Of the bearings 23a, 23b, the second bearing 23b arranged on the opposite side of the motor section 2 is arranged radially side by side with the second floating seal 18b arranged on the opposite side of the output section 13 from the motor section 2. The fixed section 12 is rotatably supported by the output section 13 via the bearings 23a, 23b.

[0033] <Fixed part> The fixed portion 12 includes an end plate portion 24 and a base plate portion 25 arranged side by side in the axial direction. The end plate portion 24 is arranged on the motor unit 2 side. The end plate portion 24 has a disk-shaped end plate body 26 rotatably supported by the first bearing 23a. An annular block 27 having a circular ring shape is integrally molded on an outer peripheral surface 26a of the end plate body 26. The annular block 27 protrudes radially outward from the outer peripheral surface 26a of the end plate body 26, and protrudes from an end surface 26b of the end plate body 26 on the motor unit 2 side toward the motor unit 2 side.

[0034] The annular block 27 covers the first bearing 23a and the first floating seal 18a from the axially outer side. A third seal accommodating recess 28 is formed in a first end face 27a of the annular block 27 on the output section 13 side. The third seal accommodating recess 28 is disposed at a position facing the first seal accommodating recess 16 in the axial direction. The third seal accommodating recess 28 is formed in an annular shape when viewed in the axial direction. The third seal accommodating recess 28 is provided with a third floating seal 18c. The motor case 4 is fixed to a second end face 27b on the motor section 2 side of the annular block 27 configured in this manner.

[0035] The substrate 25 is disposed on the opposite side to the motor 2 across the end plate 24. The substrate 25 has a disk-shaped substrate body 29 rotatably supported by the second bearing 23b. Three cylindrical pillars 31 are integrally formed on a first end face 29a of the substrate body 29 on the motor 2 side (end plate 24 side). The three pillars 31 protrude from the first end face 29a toward the motor 2 side. The three pillars 31 are disposed at equal intervals in the circumferential direction. The end plate body 26 is disposed on the tip 31a of the pillars 31. The end plate body 26 is fastened and fixed to the pillars 31 by bolts 32. In this state, a space having a constant width in the axial direction is formed between the end plate body 26 and the substrate body 29.

[0036] Center through holes 33, 34 are formed in the radial centers of the end plate body 26 and the base body 29, respectively. A bearing 37 is provided in each of the center through holes 33, 34. A plurality of (for example, three in this embodiment) crank through holes 35, 36 are formed around the center through holes 33, 34 in the end plate body 26 and the base plate body 29, respectively. The crank through holes 35, 36 are disposed at equal intervals in the circumferential direction. A bearing 38 is provided in the crank through holes 35, 36. The bearings 37, 38 are for rotatably supporting a part of the reduction gear mechanism 14 on the end plate body 26 and the base plate body 29.

[0037] <Deceleration mechanism> The reduction mechanism 14 is a so-called eccentric oscillating type reduction mechanism. The reduction mechanism 14 mainly includes an input shaft 41 inserted through the center through holes 33, 34, a plurality of crankshafts 42 inserted through each crank through hole 35, 36, and two oscillating gears 43, 44 arranged between the end plate body 26 and the base plate body 29. The input shaft 41 is rotatably supported by the end plate body 26 and the base plate body 29 via the bearings 37 of the center through holes 33, 34. The input shaft 41 is coaxial with the rotor rotation axis A1. The crankshaft 42 is rotatably supported by the end plate body 26 and the base plate body 29 via the bearings 38 of the crank through holes 35, 36. The crank rotation axis A2 of the crankshaft 42 is parallel to the rotor rotation axis A1.

[0038] The input shaft 41 is connected to an end 10a of the rotor shaft 10 on the side of the reduction gear unit 3, and rotates integrally with the rotor shaft 10. An input gear 45 is fitted and fixed to the input shaft 41 on the side of the motor unit 2. A transmission gear 46 that meshes with the input gear 45 is fitted and fixed to the crankshaft 42. A first eccentric portion 42a and a second eccentric portion 42b are formed in the axial center of the crankshaft 42 and between the end plate body 26 and the base plate body 29.

[0039] The first eccentric portion 42a is disposed on the end plate main body 26 side. The second eccentric portion 42b is disposed on the base plate main body 29 side. Each of the eccentric portions 42a, 42b is eccentric from the crank rotation axis A2. The first eccentric portion 42a and the second eccentric portion 42b are out of phase with each other. The first eccentric portion 42a supports the first oscillating gear 43 via a first bearing 47 so as to be freely rotatable. The second eccentric portion 42b supports the second oscillating gear 44 via a second bearing 48 so as to be freely rotatable.

[0040] Crank through holes 51, 52 are formed in the first oscillating gear 43 and the second oscillating gear 44 at positions corresponding to the crankshaft 42, respectively. A first bearing 47 is fitted and fixed in the crank through hole 51 of the first oscillating gear 43. A second bearing 48 is fitted and fixed in the crank through hole 52 of the second oscillating gear 44. Center through holes 53, 54, through which the input shaft 41 is inserted, are formed in the radial center of each oscillating gear 43, 44. External teeth 43a, 44a that mesh with the internal teeth 19 of the output portion 13 are formed on the outer periphery of each oscillating gear 43, 44.

[0041] A disk-shaped cover (an example of a second member in the claims) 60 is provided on a second end surface 29b of the substrate body 29 opposite to the motor section 2. The cover 60 is fastened and fixed to the substrate body 29 by bolts 61. The diameter of the cover 60 is substantially the same as the outer peripheral surface 13a of the output section 13. Therefore, the cover 60 covers the second opening 13e on the cover 60 side in the axial direction of the output section 13. In other words, the cover 60 covers the second floating seal 18b from the outside in the axial direction. The cover 60 is formed of the same material as a seal ring 71 (described later) of the second floating seal 18b.

[0042] <Sealing device> <Floating seal> The three floating seals 18a, 18b, 18c provided in the drive unit 1 prevent dust and other particles from entering the inside of the reduction gear unit 3 and prevent lubricant and other particles from leaking from the inside of the reduction gear unit 3 to the outside. Hereinafter, this prevention will be referred to as "sealing."

[0043] The three floating seals 18a, 18b, and 18c have the same configuration. Therefore, in the following description, of the three floating seals 18a, 18b, and 18c, only the second floating seal 18b constituting the seal device 70 will be described in detail. The components constituting the other two floating seals 18a and 18c will be denoted by the same reference numerals as those constituting the second floating seal 18b, and description thereof will be omitted.

[0044] FIG. 3 is an enlarged view of part III in FIG. As shown in Figures 2 and 3, the second floating seal 18b comprises an annular seal ring 71 arranged radially spaced from the inner surface 17b of the second seal accommodating recess 17, and an O-ring 72 arranged between the seal ring 71 and the inner surface 17b of the second seal accommodating recess 17. The seal ring 71 is made of cast iron. The seal ring 71 is preferably made of high chromium cast iron. High chromium cast iron has high thermal conductivity and high wear resistance (slidability). However, the seal ring 71 is not limited to this, and various materials can be used as the material for forming the seal ring 71.

[0045] The seal ring 71 is formed integrally with an annular ring body 73 and a flange portion 74 that projects radially outward from the end of the ring body 73 on the cover 60 side. The ring body 73 has a tapered outer peripheral surface 73a radially opposed to the inner peripheral surface 17b of the second seal storage recess 17, an inner peripheral surface 73b radially opposed to the tapered outer peripheral surface 73a, a tapered surface 73c formed at the end of the inner peripheral surface 73b on the cover 60 side, and a back surface 73d connecting the tapered outer peripheral surface 73a and the inner peripheral surface 73b at the end opposite the flange portion 74.

[0046] The tapered outer peripheral surface 73a is inclined so that the outer diameter gradually increases from the back surface 73d toward the flange portion 74. The tapered surface 73c is inclined so that the inner diameter gradually increases from the inner peripheral surface 73b toward the cover 60. The flange 74 has an end surface 74a on the cover 60 side formed flat along the radial direction. The end surface 74a functions as a sealing surface 74b and is in contact with the cover 60.

[0047] The O-ring 72 is elastically deformable. The O-ring 72 is arranged between the inner peripheral surface 17b of the second seal housing recess 17 and the tapered outer peripheral surface 73a of the ring body 73 in a slightly compressed state. Since the inner peripheral surface 17b and the tapered outer peripheral surface 73a are formed at an incline, the O-ring 72 presses the seal surface 74b of the flange portion 74 toward the cover 60. Meanwhile, the cover 60 presses the seal surface 74b of the flange portion 74 from the axially outer side. This seals the gap between the cover 60 and the seal ring 71. The O-ring 72 seals the gap between the inner peripheral surface 17b of the second seal housing recess 17 and the seal ring 71. That is, the second floating seal 18b seals the gap between the output portion 13 and the cover 60.

[0048] The first floating seal 18a and the third floating seal 18c are arranged so as to overlap each other, thereby providing a seal between the output portion 13 and the annular block 27. That is, the floating seals 18a and 18c are arranged so that the seal surfaces 74b of the seal rings 71 abut against each other. This provides a seal between the seal surfaces 74b.

[0049] <Operation of the drive unit> Next, the operation of the driving device 1 will be described. When the rotor shaft 10 is rotated by the drive of the motor unit 2, the input shaft 41 is rotated integrally with the rotor shaft 10. Since the input gear 45 of the input shaft 41 and the transmission gear 46 of the crankshaft 42 are meshed with each other, the rotation of the input shaft 41 is transmitted to the crankshaft 42. This rotates each of the crankshafts 42. Then, each of the oscillating gears 43, 44 is oscillatingly rotated while meshing with the internal teeth 19 of the output unit 13.

[0050] As a result, the fixed portion 12 and the output portion 13 rotate relative to each other. The rotation of the rotor shaft 10 is reduced in speed by the reduction mechanism 14 and transmitted to the output portion 13. The fixed portion 12 is fixed to a motor case 4. The motor case 4 is fixed to a boom 108. On the other hand, the output portion 13 is fixed to an arm 109. Therefore, the arm 109 is rotated relative to the boom 108 about the rotor rotation axis A1.

[0051] The fixed portion 12 includes an annular block 27 provided on the end plate portion 24 and a cover 60 fastened and fixed to the base plate portion 25. Therefore, a seal surface 74b of a seal ring 71 constituting the second floating seal 18b slides against the cover 60. Even while sliding, the output portion 13 and the cover 60 are sealed by the second floating seal 18b. The seal surfaces 74b of the seal rings 71 of the first floating seal 18a and the third floating seal 18c also slide against each other. While sliding, the first floating seal 18a and the third floating seal 18c seal between the output portion 13 and the end plate portion 24 (annular block 27).

[0052] Thus, the above-mentioned sealing device 70 includes the output portion 13 as a first member, the cover 60 as a second member, and the second floating seal 18b. The output portion 13 is formed with a second seal housing portion 17 having an inner peripheral surface 17b. The cover 60 rotates with respect to the output portion 13 and is disposed facing the output portion 13 in the axial direction. The second floating seal 18b is housed in the second seal housing portion 17. The second floating seal 18b includes a seal ring 71 and an O-ring 72. The O-ring 72 presses the seal surface 74b of the seal ring 71 toward the cover 60. This ensures sealing between the seal ring 71 and the cover 60.

[0053] Therefore, instead of using a pair of floating seals (seal rings 71) as in the conventional case, it is possible to configure the seal device 70 with a single seal ring 71. This allows the seal device 70 to be made smaller while ensuring high sealing performance and durability of the seal device 70. The cover 60 is attached to the fixed portion 12 as a third member that is provided rotatably relative to the output portion 13. The cover 60 that constitutes the speed reduction portion 3 also serves as a part of the sealing device 70. Therefore, the speed reduction portion 3 equipped with the sealing device 70 can be made compact.

[0054] The first floating seal 18a and the second floating seal 18b are arranged radially next to the corresponding bearings 23a, 23b, respectively, so that the axial length of the reduction gear section 3 can be made shorter than when the floating seals 18a, 18b and the bearings 23a, 23b are arranged axially next to each other. The sealing device 70 can be suitably used in a configuration such as the speed reducing portion 3. The shovel 100 equipped with the sealing device 70 has high sealing performance and is compact, making it possible to provide a highly functional shovel 100.

[0055] In the above embodiment, the output portion 13 is the first member, the cover 60 is the second member, and the O-ring 72 presses the seal surface 74b of the seal ring 71 against the cover 60 to ensure sealing between the seal ring 71 and the cover 60. However, this is not limited to this, and various combinations of the first member and the second member are possible. This will be described in detail below.

[0056] [First Modification] Fig. 4 is a cross-sectional view of a seal device 70 in a first modified example. Fig. 4 corresponds to Fig. 3 described above. As shown in Fig. 4, the second floating seal 18b may be attached in the opposite direction. In this case, the second seal storage recess 17 is not provided in the output section 13, and a ring-shaped seal storage housing 62 is provided on one surface 60a of the cover 60 on the output section 13 side. The seal storage housing 62 has an inner circumferential surface 62a. The inner circumferential surface 62a is inclined so that the inner diameter gradually increases toward the output section 13.

[0057] The seal ring 71 of the second floating seal 18b is disposed at a radial distance from the inner circumferential surface 62a of the seal accommodating housing 62. The O-ring 72 is disposed between the inner circumferential surface 62a of the seal accommodating housing 62 and the tapered outer circumferential surface 73a of the seal ring 71. In this configuration, the O-ring 72 presses the seal surface 74b of the flange portion 74 toward the end face 13c of the output portion 13 on the cover 60 side. That is, the output portion 13 is the second member, and the cover 60 is the first member. Even in this configuration, the same effects as those of the above-mentioned embodiment can be achieved.

[0058] [Second modified example] FIG. 5 is a cross-sectional view of the speed reducer portion 30 in the second modified example. In the above embodiment, the sealing device 70 is configured by the second floating seal 18b and the cover 60. However, this is not limited to the above, and as shown in Fig. 5, the sealing device 70 may be configured by the first floating seal 18a provided on the side of the output section 13 opposite the cover 60, and an annular block 27 disposed axially opposite the first floating seal 18a.

[0059] In this case, the third seal housing recess 28 is not formed in the first end face 27a of the annular block 27, and the third floating seal 18c is not provided. With this configuration, the O-ring 72 of the first floating seal 18a presses the seal surface 74b of the seal ring 71 toward the first end face 27a of the annular block 27. Meanwhile, the annular block 27 presses the seal surface 74b of the seal ring 71 from the axially outer side. That is, the output portion 13 becomes the first member, and the end plate portion 24 (annular block 27) becomes the second member. As a result, the first floating seal 18a seals between the output portion 13 and the end plate portion 24 (annular block 27). The annular block 27 can also be said to be a cover that closes the first opening 13d on the motor portion 2 side of the output portion 13. Therefore, according to the second modified example, the same effects as those of the above-mentioned embodiment are achieved.

[0060] [Third Modification] FIG. 6 is a cross-sectional view of the speed reducer portion 30 in the third modified example. In the above embodiment, the reduction mechanism 14 of the reduction unit 30 is a so-called eccentric oscillating type reduction mechanism. The reduction mechanism of the eccentric oscillating type is provided with a plurality of crankshafts 42 (for example, three) arranged around the input shaft 41. The rotation of the crankshafts 42 causes the oscillating gears 43, 44 to rotate in an oscillating manner. However, this is not limited to the above, and as shown in FIG. 6, the input shaft 41 may be a center crankshaft 81. In this case, the crankshaft 42 is replaced with a connecting shaft 82 that does not have the eccentric parts 42a, 42b. The connecting shaft 82 connects the end plate body 26 and the base body 29.

[0061] A first eccentric portion 81a and a second eccentric portion 81b are formed in the axial center of the center crankshaft 81 and between the end plate body 26 and the base plate body 29. The first eccentric portion 81a is disposed on the end plate body 26 side. The second eccentric portion 81b is disposed on the base plate body 29 side. The eccentric portions 81a and 81b are eccentric from the rotor rotation axis A1. The first eccentric portion 81a and the second eccentric portion 81b are shifted in phase angle from each other. The first eccentric portion 81a supports the first oscillating gear 43 rotatably via a first bearing 83. The second oscillating gear 44 is supported rotatably via a second bearing 84 by the second eccentric portion 81b.

[0062] With this configuration, the center crankshaft 81 rotates integrally with the rotor shaft 10. The oscillating gears 43, 44 are oscillatingly rotated in accordance with the rotation of the center crankshaft 81. Therefore, according to the third modified example, the same effects as those of the above-described embodiment are achieved.

[0063] In addition, the third modified example does not require the input gear 45 and the transmission gear 46 (see FIG. 2) for transmitting rotational force to each crankshaft 42 as in the above-described embodiment. Therefore, there is no need to secure space for arranging the input gear 45 and the transmission gear 46 on the motor unit 2 side of the end plate main body 26. Therefore, the axial thickness of the annular block 27 can be made thinner. The annular block 27 and the first floating seal 18a form a seal device 70.

[0064] In the third modified example, the substrate portion 25 and the cover 60 are integrally formed, and the third floating seal 18c is provided on the cover 60. That is, a ring-shaped seal storage housing 62 is provided on one surface 60a of the cover 60 on the output portion 13 side. The third floating seal 18c is provided on the seal storage housing 62. The attachment direction of this third floating seal 18c is the same as the attachment direction of the second floating seal 18b in the first modified example (see FIG. 4). Therefore, the second floating seal 18b and the third floating seal 18c butt against each other at their seal surfaces 74b. This provides a seal between the output portion 13 and the cover 60.

[0065] In the third modified example, the case has been described where the gap between the output unit 13 and the cover 60 is sealed using two floating seals 18b, 18c. However, this is not limited to this, and the gap between the output unit 13 and the cover 60 may be sealed using a sealing device 70 (the second floating seal 18b and the cover 60) in the same manner as in the above-described embodiment.

[0066] The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention. For example, in the above embodiment, the shovel 100 has been described as a construction machine. However, the present invention is not limited to this, and the configurations of the above embodiment and modified examples can be adopted in various construction machines having two members that can rotate relative to one another. The configurations of the above embodiment and modified examples can be adopted in drive devices having two members that can rotate relative to one another other than construction machines.

[0067] In the above embodiment, the case where the output part 13 is rotated relative to the fixed part 12 has been described. However, this is not limited to this, and the output part 13 may be fixed and the fixed part 12 may be rotated relative to the output part 13. Then, a member fixed to the fixed part 12 may be rotated around the rotor rotation axis A1.

[0068] In the above embodiment, the cover 60 is formed from the same material as the seal rings 71 of the floating seals 18a to 18c. However, this is not limited to the above, and the material of the cover 60 and the material of the seal rings 71 may be different. It is preferable that the rigidity of the cover 60 is the same as the rigidity of the seal rings 71.

[0069] In the above embodiment, the reduction mechanism 14 is an eccentric oscillating type reduction mechanism having the crankshaft 42 and the center crankshaft 81, as well as the oscillating gears 43, 44. However, the present invention is not limited to this, and various reduction mechanisms can be applied. For example, a planetary gear reduction mechanism can be applied instead of the eccentric oscillating type reduction mechanism. A speed-up mechanism that increases the speed of rotation of the rotor shaft 10 and outputs it can be used instead of the reduction mechanism. The speed reducer 3 may be replaced by a simple rotating device.

[0070] In the above embodiment, a case has been described in which the O-ring 72 is used as the elastic ring disposed on the tapered outer peripheral surface 73a of the seal ring 71. However, the present invention is not limited to this, and any other elastically deformable ring may be used in place of the O-ring 72. In the above embodiment, the cover 60 is fastened to the base plate portion 25 (base plate body 29) by the bolts 61. However, this is not limited to this, and the base plate portion 25 and the cover 60 may be integrally formed.

[0071] Among the embodiments disclosed in this specification, those that are composed of multiple objects may be integrated, and conversely, those that are composed of one object may be divided into multiple objects. Regardless of whether they are integrated or not, it is sufficient that they are configured to achieve the object of the invention. [Explanation of symbols]

[0072] 12...Fixed portion (third member) 13... Output section (first member, second member) 13d,13e...opening 14...Reduction mechanism (transmission mechanism) 16…First seal storage recess 16b, 17b, 62a...Inner peripheral surface 17…Second seal storage recess 18a…First floating seal 18b…Second floating seal 18c…3rd floating seal 23a…First bearing (bearing) 23b…Second bearing (bearing) 24...End plate portion (third member) 25...Substrate portion (third member) 26…End plate body 27...Annular block (second member, cover) 29…Board body 29b…Second end face (end face) 60...Cover (first member, second member) 62…Seal storage housing 70…Sealing device 71…Seal ring 72...O-ring (elastic ring) 73…Ring body 73a...Tapered outer periphery (outer periphery) 74…Flange 74b…Seal surface 100…Shovel (construction machinery) 101...Running body (car body) 103...Rotating body (car body) 104...Action part (vehicle body) A1...Rotor rotation axis (rotation axis)

Claims

1. A first member having an inner circumferential surface; A second member that rotates relative to the first member and is disposed opposite the first member in a rotation axis direction; a seal ring having an outer circumferential surface that faces the inner circumferential surface in a radial direction with a gap therebetween and having a seal surface that comes into sliding contact with the second member; an elastic ring that is disposed between the inner circumferential surface of the first member and the outer circumferential surface of the seal ring and that is elastically deformable; Equipped with The elastic ring presses the seal surface of the seal ring against the second member, thereby forming a seal between the seal surface and the second member. Sealing device.

2. The first member is formed in a cylindrical shape having an opening, a third member that is accommodated in the first member and is rotatably provided with respect to the first member; The second member is a cover provided at an end of the third member in the rotation axis direction and closing the opening of the first member. The sealing device of claim 1 .

3. The first member and the third member are relatively rotatable via a bearing, The seal ring and the elastic ring are arranged side by side in a radial direction perpendicular to the rotation axis with respect to the bearing. The sealing device according to claim 2 .

4. The first member and the third member are connected via a speed change mechanism, The rotation of one of the first member and the third member is transmitted to the other of the first member and the third member at a changed speed. The sealing device according to claim 3.

5. The second member is formed in a cylindrical shape having an opening, a third member housed within the second member and rotatably provided with respect to the second member; the first member is a cover provided at an end of the third member in the rotation axis direction and configured to close the opening of the second member, The seal surface is pressed against an end portion of the second member in the rotation axis direction. The sealing device of claim 1 .

6. The second member and the third member are relatively rotatable via a bearing, The seal ring and the elastic ring are arranged side by side in a radial direction perpendicular to the rotation axis with respect to the bearing. The sealing device according to claim 5.

7. The second member and the third member are connected via a speed change mechanism, The rotation of one of the second member and the third member is transmitted to the other of the second member and the third member at a changed speed. The sealing device according to claim 6.

8. The sealing device includes a vehicle body having a working part, The sealing device comprises: A first member having an inner circumferential surface shared with a portion of the movable portion; a second member that rotates relative to the first member, is disposed opposite the first member in a rotation axis direction, and is shared with a part of the movable portion; a seal ring having an outer circumferential surface that faces the inner circumferential surface in a radial direction with a gap therebetween and having a seal surface that comes into sliding contact with the second member; an elastic ring that is disposed between the inner circumferential surface of the first member and the outer circumferential surface of the seal ring and that is elastically deformable; Equipped with The elastic ring presses the seal surface of the seal ring against the second member, thereby forming a seal between the seal surface and the second member. Construction machinery.

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