Sealing device and construction machine

Abstract

The invention relates to a sealing device and construction machinery. The sealing device includes a first member, a second member, a seal ring, and an elastic ring. The first member has an inner peripheral surface. The second member rotates with respect to the first member. The second member is disposed so as to face the first member in the rotational axis direction. The seal ring has an outer peripheral surface facing the inner peripheral surface in the radial direction so as to be spaced apart from the inner peripheral surface. The seal ring has a seal surface that is in contact with the second member so as to slide with respect to the second member. An elastic ring is disposed between the inner peripheral surface of the first member and the outer peripheral surface of the seal ring. The elastic ring elastically deforms. The sealing surface of the seal ring is pressed toward the second member by the elastic ring, and a space between the sealing surface and the second member is sealed.

Description

Technical Field

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

[0002] Construction machinery such as bulldozers and hydraulic excavators are used in harsh environments. Therefore, in order to prevent foreign matter such as sand from entering the construction machinery and lubricating oil from leaking out, a sealing device with high sealing performance and durability is used in the operating parts constituting the construction machinery. As such a sealing device, for example, a floating sealing device is known. The floating sealing device includes: a pair of sealing rings that seal between a first member and a second member that rotate relatively; and an O-ring that is provided on the outer peripheral surface of each sealing ring.

[0003] The first member and the second member are respectively formed with a recessed portion for accommodating a sealing ring. The sealing ring is arranged on the inner peripheral surface of each of the first member and the second member in a manner spaced apart in the radial direction. The sealing ring has a sealing surface. When the sealing ring is respectively accommodated in the first member and the second member, the sealing surfaces in the first member and the second member are butted against each other. The sealing surfaces slide against each other.

[0004] The O-ring is clamped by the inner circumference of each of the first component and the second component and the outer circumference of the sealing ring. The outer circumference of the sealing ring is formed in an inclined manner. Therefore, the sealing surfaces of a pair of sealing rings are pressed against each other by the O-ring. Thus, the first component and the second component are sealed.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6453880 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] As described above, the floating seal device needs to house the seal ring in the first member and the second member, respectively. Therefore, there is a problem that the seal device becomes larger.

[0010] The present invention provides a sealing device and a construction machine which have high sealing performance and durability and can be miniaturized.

[0011] Solutions for solving problems

[0012] A sealing device according to one aspect of the present invention comprises: a first member having an inner peripheral surface; a second member rotating relative to the first member and arranged to be opposite to the first member in the direction of the rotation axis; a sealing ring having an outer peripheral surface radially opposite to the inner peripheral surface at a distance from the inner peripheral surface and having a sealing surface contacting the second member in a sliding manner relative to the second member; and an elastic ring arranged between the inner peripheral surface of the first member and the outer peripheral surface of the sealing ring and elastically deformed. The sealing surface of the sealing ring is pressed toward the second member by the elastic ring, so that the sealing surface and the second member are sealed.

[0013] By configuring in this way, the sealing device can be configured using one sealing ring. Therefore, the sealing device can have high sealing performance, durability, and can be downsized.

[0014] Alternatively, the structure may include a third member, the third member being housed in the first member and being arranged to be rotatable relative to the first member. Alternatively, the first member may be formed into a cylindrical shape having an opening. Alternatively, the second member may be a cover provided to an end of the third member in the direction of the rotation axis. Alternatively, the cover may block the opening of the first member.

[0015] In the above structure, the first member and the third member may be relatively rotatable via a bearing. The seal ring and the elastic ring may be arranged in parallel with the bearing in a radial direction orthogonal to the rotation axis.

[0016] The above structure may include a speed change mechanism connecting the first member and the third member. The speed change mechanism may change the speed of rotation of one of the first member and the third member and transmit the rotation to the other of the first member and the third member.

[0017] Alternatively, the structure may include a third member, the third member being housed in the second member and being arranged to be rotatable relative to the second member. Alternatively, the second member may be formed into a cylindrical shape having an opening. Alternatively, the first member may be a cover provided to the end of the third member in the direction of the rotation axis. Alternatively, the cover may seal the opening of the second member. Alternatively, the sealing surface may be pressed against the end of the second member in the direction of the rotation axis.

[0018] In the above configuration, the second member and the third member may be relatively rotatable via a bearing. The seal ring and the elastic ring may be arranged in parallel with the bearing in a radial direction orthogonal to the rotation axis.

[0019] Alternatively, the above structure may include a speed change mechanism connecting the second member and the third member. Alternatively, the speed change mechanism changes the rotation speed of one of the second member and the third member and transmits the rotation speed to the other of the second member and the third member.

[0020] A construction machine according to another aspect of the present invention includes a vehicle body, and the vehicle body includes a running part provided with a sealing device. The sealing device includes: a first member, which is shared with a part of the running part and has an inner peripheral surface; a second member, which rotates relative to the first member and is arranged in a manner opposite to the first member in the direction of the rotation axis and is shared with a part of the running part; a sealing ring, which has an outer peripheral surface radially opposite to the inner peripheral surface in a manner spaced apart from the inner peripheral surface, and has a sealing surface that contacts the second member in a manner sliding relative to the second member; and an elastic ring, which is arranged between the inner peripheral surface of the first member and the outer peripheral surface of the sealing ring and is elastically deformed. The sealing surface of the sealing ring is pressed toward the second member by the elastic ring, so that the sealing surface and the second member are sealed.

[0021] By configuring in this way, the sealing device can be configured using one sealing ring. Therefore, a high sealing performance can be ensured in the sealing device, and durability can be ensured, and the device can be miniaturized. Thus, a high-performance construction machine can be provided.

[0022] Effects of the Invention

[0023] The sealing device and construction machine described above have high sealing performance and durability and can be miniaturized. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of the excavator according to the embodiment of the present invention as viewed from the side.

[0025] Figure 2 It is a cross-sectional view showing a driving device in an embodiment of the present invention.

[0026] Figure 3 yes Figure 2 Enlarged view of Part III.

[0027] Figure 4 It is a cross-sectional view showing a first modified example of the sealing device according to the embodiment of the present invention.

[0028] Figure 5 It is a cross-sectional view showing a second modified example of the speed reduction portion according to the embodiment of the present invention.

[0029] Figure 6It is a cross-sectional view showing a third modified example of the speed reduction portion according to the embodiment of the present invention.

[0030] Description of Reference Numerals

[0031] 12. Fixed portion (third member); 13. Output portion (first member, second member); 13d, 13e, opening portion; 14. Speed ​​reduction mechanism (speed change mechanism); 16. First seal receiving recess; 16b, 17b, 62a, inner peripheral surface; 17. Second seal receiving recess; 18a, first floating seal; 18b, second floating seal; 18c, third floating seal; 23a, first bearing (bearing); 23b, second bearing (bearing); 24, end plate portion (third member); 25. Base plate portion (third member); 26. End plate body; 27. Annular block (second component, cover); 29. ​​Base plate body; 29b. Second end face (end face); 60. Cover (first component, second component); 62. Sealing housing shell; 70. Sealing device; 71. Sealing ring; 72. O-ring (elastic ring); 73. Ring body; 73a. Conical outer peripheral surface (outer peripheral surface); 74. Flange portion; 74b. Sealing surface; 100. Excavator (construction machinery); 101. Traveling body (body); 103. Rotating body (body); 104. Action part (body); A1. Rotation axis of rotor (rotation axis). DETAILED DESCRIPTION

[0032] Next, embodiments of the present invention will be described based on the drawings.

[0033] <Excavator>

[0034] Figure 1 This is a schematic diagram of an excavator 100 as an example of a construction machine according to an embodiment of the present invention, as viewed from the side. In the following description, the front that an operator (not shown) operating the excavator 100 is facing is referred to as the front. The side opposite to the front in the horizontal direction is referred to as the rear. The up-and-down direction when the excavator 100 is placed on the road surface is referred to as the up-and-down direction. The direction perpendicular to the front-and-back direction and the up-and-down direction is referred to as the vehicle width direction. Figure 1 , a state of the excavator 100 as viewed from the vehicle width direction is shown.

[0035] like Figure 1 As shown, the excavator 100 includes a traveling body 101 that moves by itself, a revolving body 103 that is provided on the upper part of the traveling body 101 via a revolving mechanism 102 , and an action unit 104 that is provided on the revolving body 103 .

[0036] The traveling body 101 and the revolving mechanism 102 are driven by, for example, an electric motor with a speed reducer (not shown). The traveling body 101 includes, for example, two crawlers 105 arranged in the vehicle width direction. However, the structure of the traveling body 101 is not limited to this embodiment, and wheels or the like may be used instead of the crawlers 105. The revolving body 103 revolves relative to the traveling body 101.

[0037] 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 the drive device 1.

[0038] 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 device 1. Figure 1 In the figure, the driving device 1 provided to one end of the boom 108 is omitted.

[0039] One end 109a of the arm 109 in the longitudinal direction is rotatably connected to the other end 108a of the boom 108 in the longitudinal direction opposite to the one end by means of the drive device 1. The bucket 110 is rotatably connected to the other end 109b of the arm 109 in the longitudinal direction opposite to the one end 109a by means of the drive device 1.

[0040] The drive devices 1 provided in the respective parts all have the same structure. Therefore, in the following description, only the drive device 1 connecting the one end 109a of the arm 109 and the other end 108a of the boom 108 will be described, and descriptions of the other drive devices 1 will be omitted.

[0041] <Drive device>

[0042] Figure 2 It is a cross-sectional view showing the driving device 1 .

[0043] like Figure 2 As shown, the drive device 1 includes a motor unit 2 and a speed reduction unit 3. The motor unit 2 is fixed to the other end 108a of the boom 108. The speed reduction unit 3 is connected to the motor unit 2 and is fixed to one end 109a of the arm 109.

[0044] <Motor unit>

[0045] The motor unit 2 includes a motor case 4, a stator 5, and a rotor 6. The motor case 4 is fixed to the boom 108. The stator 5 is accommodated in the motor case 4. The stator 5 is formed in a cylindrical shape. The rotor 6 is provided on the radially inner side of the stator 5.

[0046] 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 .

[0047] The rotor 6 includes a rotor shaft 10 and a rotor core 11. The rotor shaft 10 is rotatably supported by the motor case 4 via bearings 9a and 9b. The rotor core 11 is fitted and fixed to the outer peripheral surface of the rotor shaft 10. The rotor core 11 is provided with a magnet (not shown).

[0048] In such a structure, when the coil 8 is energized, an interlinked magnetic flux is generated in the stator 5. Magnetic attraction and magnetic repulsion are generated between the interlinked magnetic flux and the magnets of the rotor 6. As a result, the rotor core 11 and the rotor shaft 10 continue to rotate integrally. The rotor rotation axis A1 of the rotor shaft 10 coincides with the rotation axis of the boom 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 that is orthogonal to the axial direction and the circumferential direction is referred to as the radial direction.

[0049] <Deceleration unit>

[0050] The speed reduction unit 3 includes a fixed unit (an example of the third member in the claims) 12, an output unit (an example of the first member in the claims) 13, a speed reduction mechanism 14, and a sealing device 70. The fixed unit 12 is fixed to the motor housing 4. The output unit 13 is provided so as to surround the fixed unit 12. The output unit 13 is supported so as to be rotatable relative to the fixed unit 12. The output unit 13 is formed in a cylindrical shape. The speed reduction mechanism 14 is connected to the rotor shaft 10. The sealing device 70 is provided at the fixed unit 12 and the output unit 13. The speed reduction mechanism 14 is an example of a speed change mechanism.

[0051] The central axis of the output portion 13 coincides with the rotor rotation axis A1. An outer flange portion 15 extending radially outward is integrally formed on an outer peripheral surface 13a of the output portion 13. One end 109a of the arm 109 is fixed to the outer flange portion 15.

[0052] Seal housing recesses 16 and 17 (first seal housing recess 16 and second seal housing recess 17) are formed on the axially outer side of the output portion 13. The seal housing recesses 16 and 17 are formed by increasing the diameter of the step portions 16a and 17a relative to the diameter of the inner peripheral surface 13b in the output portion 13. The seal housing recesses 16 and 17 are each opened on the axially outer side. In other words, openings 13d and 13e (first opening 13d and second opening 13e) are formed on the axially outer side of the output portion 13. The inner peripheral surfaces 16b and 17b of the seal housing recesses 16 and 17 are inclined in a manner that the inner diameter gradually increases as they go toward the axially outer side.

[0053] A first floating seal 18a is provided in the first seal housing recess 16 on the motor unit 2 side of the seal housing recesses 16 and 17. A second floating seal 18b is provided in the second seal housing recess 17 on the side opposite to the motor unit 2 of the seal housing recesses 16 and 17. The second floating seal 18b constitutes the sealing device 70. The structures of the floating seals 18a and 18b will be described in detail later.

[0054] 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 plurality of internal teeth 19 are arranged in the majority of the axial center of the inner circumferential surface 13b. The plurality of internal teeth 19 are arranged at equal intervals in the circumferential direction.

[0055] Bearing housings 21 and 22 are integrally formed at radially inner sides of the seal housing recesses 16 and 17 and at positions axially outer sides of the inner teeth 19. The bearing housings 21 and 22 protrude axially outward from the corresponding step portions 16a and 17a, respectively. The bearing housings 21 and 22 are each formed into a cylindrical shape centered on the rotor rotation axis A1. The bearing housing 21 is provided with a bearing 23a (first bearing 23a). The bearing housing 22 is provided with a bearing 23b (second bearing 23b).

[0056] That is, the first bearing 23a disposed on the motor part 2 side of the bearings 23a and 23b is arranged radially in parallel with the first floating seal 18a disposed on the motor part 2 side of the output part 13. The second bearing 23b disposed on the side opposite to the motor part 2 of the bearings 23a and 23b is arranged radially in parallel with the second floating seal 18b disposed on the side opposite to the motor part 2 of the output part 13. The fixed part 12 is rotatably supported by the output part 13 via the bearings 23a and 23b.

[0057] <Fixed part>

[0058] The fixing portion 12 includes an end plate portion 24 and a base plate portion 25 arranged in an axial direction. The end plate portion 24 is arranged on the motor portion 2 side. The end plate portion 24 has an end plate body 26 supported by a first bearing 23a in a rotatable circular plate shape. An annular block 27 is integrally formed on the 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. The annular block 27 protrudes from the end surface 26b of the end plate body 26 on the motor portion 2 side toward the motor portion 2 side.

[0059] The annular block 27 covers the first bearing 23a and the first floating seal 18a from the axially outer side. A third seal housing recess 28 is formed on the first end face 27a of the annular block 27 on the output portion 13 side. The third seal housing recess 28 is arranged at a position opposite to the first seal housing recess 16 in the axial direction. The third seal housing recess 28 is formed in a circular ring shape when viewed from the axial direction. The third floating seal 18c is provided in the third seal housing recess 28. The motor housing 4 is fixed to the second end face 27b of the annular block 27 constructed in this way on the motor portion 2 side.

[0060] The substrate portion 25 is arranged on the side opposite to the motor portion 2 across the end plate portion 24. The substrate portion 25 has a substrate body 29 that is supported by a second bearing 23b in a rotatable circular plate shape. Three cylindrical pillar portions 31 are integrally formed on the first end face 29a of the substrate body 29 on the motor portion 2 side (end plate portion 24 side). The three pillar portions 31 protrude from the first end face 29a toward the motor portion 2 side. The three pillar portions 31 are arranged at equal intervals in the circumferential direction. The end plate body 26 is arranged at the top end 31a of the pillar portion 31. The end plate body 26 is fastened to the pillar portion 31 by bolts 32. In this state, a space having a certain width in the axial direction is formed between the end plate body 26 and the substrate body 29.

[0061] A central through hole 33 is formed in the radial center of the end plate body 26. A central through hole 34 is formed in the radial center of the base plate body 29. Bearings 37 are provided in the central through holes 33, 34, respectively.

[0062] In the end plate body 26 and the base plate body 29, a plurality of (for example, three in the present embodiment) crankshaft through holes 35 and 36 are formed around the center through holes 33 and 34, respectively. The crankshaft through holes 35 are arranged at equal intervals in the circumferential direction. Similarly, the crankshaft through holes 36 are arranged at equal intervals in the circumferential direction. Bearings 38 are provided in the crankshaft through holes 35 and 36, respectively. The bearings 37 and 38 are used to support a part of the speed reduction mechanism 14 in a rotatable manner on the end plate body 26 and the base plate body 29, respectively.

[0063] <Reduction Mechanism>

[0064] The speed reduction mechanism 14 is a so-called eccentric swing type speed reduction mechanism. The speed reduction mechanism 14 has an input shaft 41, a plurality of crankshafts 42, and two swing gears 43, 44 as main structures. The input shaft 41 passes through the center through holes 33, 34. The plurality of crankshafts 42 pass through the crankshaft through holes 35, 36. The two swing gears 43, 44 are arranged between the end plate body 26 and the base plate body 29. The input shaft 41 is supported by the end plate body 26 and the base plate body 29 in a rotatable manner by means of 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 supported by the end plate body 26 and the base plate body 29 in a rotatable manner by means of the bearings 38 of the crankshaft through holes 35, 36. The crankshaft rotation axis A2 of the crankshaft 42 is parallel to the rotor rotation axis A1.

[0065] The input shaft 41 is connected to the end 10a of the rotor shaft 10 on the speed reducing unit 3 side. The input shaft 41 rotates integrally with the rotor shaft 10. An input gear 45 is fitted and fixed to the input shaft 41 on the motor unit 2 side.

[0066] The transmission gear 46 meshing 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 between the end plate body 26 and the base plate body 29 in the axial center of the crankshaft 42.

[0067] The first eccentric portion 42a is arranged on the end plate body 26 side. The second eccentric portion 42b is arranged on the base plate body 29 side. The eccentric portions 42a and 42b are eccentric with respect to the crankshaft rotation axis A2. The phase angles of the first eccentric portion 42a and the second eccentric portion 42b are offset from each other. The first swing gear 43 is rotatably supported by the first eccentric portion 42a via the first bearing 47. The second swing gear 44 is rotatably supported by the second eccentric portion 42b via the second bearing 48.

[0068] Crankshaft through holes 51 and 52 are formed at positions corresponding to the crankshaft 42 of the first swing gear 43 and the second swing gear 44. The first bearing 47 is fitted and fixed to the crankshaft through hole 51 of the first swing gear 43. The second bearing 48 is fitted and fixed to the crankshaft through hole 52 of the second swing gear 44. Center through holes 53 and 54 are formed in the radial center of each of the swing gears 43 and 44, through which the input shaft 41 passes. External teeth 43a and 44a that mesh with the internal teeth 19 of the output portion 13 are formed on the outer periphery of each of the swing gears 43 and 44.

[0069] A disc-shaped cover (an example of the second member in the claims) 60 is provided on the second end surface 29b of the substrate body 29 on the side opposite to the motor unit 2. The cover 60 is fastened to the substrate body 29 by bolts 61. The diameter of the cover 60 is substantially the same as the diameter of the outer peripheral surface 13a of the output unit 13. Therefore, the second opening 13e on the cover 60 side in the axial direction of the output unit 13 is covered by the cover 60. In other words, the second floating seal 18b is covered from the outside in the axial direction by the cover 60. The cover 60 is formed of the same material as the material of the sealing ring 71 of the second floating seal 18b to be discussed later.

[0070] <Sealing device>

[0071] <Floating seal>

[0072] The three floating seals 18a, 18b, 18c provided to the drive device 1 prevent dust and the like from entering the speed reduction section 3 and lubricant and the like from leaking out from the speed reduction section 3. Hereinafter, such prevention is referred to as "sealing".

[0073] The three floating seals 18a, 18b, and 18c have the same structure. Therefore, in the following description, only the second floating seal 18b constituting the sealing device 70 among the three floating seals 18a, 18b, and 18c will be described in detail. The description of each part constituting the other two floating seals 18a and 18c is marked with the same reference numerals as the reference numerals of each part constituting the second floating seal 18b, and the description is omitted.

[0074] Figure 3 yes Figure 2 Enlarged view of Part III.

[0075] like Figure 2 , Figure 3 As shown, the second floating seal 18b includes a seal ring 71 and an O-ring 72. The seal ring 71 is arranged to be spaced apart from the inner peripheral surface 17b of the second seal housing recess 17 in the radial direction. The seal ring 71 is formed in an annular shape. The O-ring 72 is arranged between the seal ring 71 and the inner peripheral surface 17b of the second seal housing recess 17.

[0076] The seal ring 71 is made of cast iron. The seal ring 71 is preferably made of high chromium cast iron. The high chromium cast iron of the seal ring 71 has high thermal conductivity and high wear resistance (sliding property). However, the material and manufacturing method of the seal ring 71 are not limited thereto. Various materials can be used as the material forming the seal ring 71.

[0077] In the seal ring 71, an annular ring body 73 and a flange portion 74 are integrally formed. The flange portion 74 protrudes radially outward from an end portion of the ring body 73 on the cover 60 side.

[0078] The ring body 73 has a tapered outer peripheral surface 73a, an inner peripheral surface 73b, a tapered surface 73c and a back surface 73d. The tapered outer peripheral surface 73a is opposite to the inner peripheral surface 17b of the second seal housing recess 17 in the radial direction. The inner peripheral surface 73b is opposite to the tapered outer peripheral surface 73a in the radial direction. The tapered surface 73c is formed at the end of the inner peripheral surface 73b on the side of the cover 60. The back surface 73d connects the tapered outer peripheral surface 73a and the inner peripheral surface 73b at the end on the side opposite to the flange portion 74.

[0079] 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.

[0080] The end surface 74 a of the flange portion 74 on the cover 60 side is formed flat in the radial direction. The end surface 74 a is a surface that functions as a sealing surface 74 b. The end surface 74 a is in contact with the cover 60.

[0081] The O-ring 72 is elastically deformable. The O-ring 72 is arranged in a slightly compressed state between the inner circumferential surface 17b of the second seal housing recess 17 and the tapered outer circumferential surface 73a of the ring body 73. The inner circumferential surface 17b and the tapered outer circumferential surface 73a are formed in an inclined manner, so that the sealing surface 74b of the flange portion 74 is pressed toward the cover 60 by the O-ring 72. On the other hand, the cover 60 presses the sealing surface 74b of the flange portion 74 from the axial outside. Thus, the cover 60 and the sealing ring 71 are sealed. The inner circumferential surface 17b of the second seal housing recess 17 and the sealing ring 71 are sealed by the O-ring 72. That is, the output portion 13 and the cover 60 are sealed by the second floating seal 18b.

[0082] The first floating seal 18a and the third floating seal 18c are arranged to overlap each other to seal between the output portion 13 and the annular block 27. That is, the floating seals 18a and 18c are arranged so that the sealing surfaces 74b of the seal rings 71 abut against each other. Thus, the sealing surfaces 74b are sealed.

[0083] <Drive device operation>

[0084] Next, the operation of the driving device 1 will be described.

[0085] When the rotor shaft 10 rotates due to the drive of the motor unit 2, the input shaft 41 rotates integrally with the rotor shaft 10. The input gear 45 of the input shaft 41 meshes with the transmission gear 46 of the crankshaft 42, so that the rotation of the input shaft 41 is transmitted to the crankshaft 42. As a result, each crankshaft 42 rotates. Then, each swing gear 43, 44 swings and rotates while meshing with the internal teeth 19 of the output unit 13.

[0086] 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 decelerated by the speed reduction mechanism 14 and transmitted to the output portion 13 .

[0087] The fixing portion 12 is fixed to the motor case 4. The motor case 4 is fixed to the boom 108. On the other hand, the output portion 13 is fixed to the arm 109. Therefore, the arm 109 rotates relative to the boom 108 around the rotor rotation axis A1.

[0088] The fixed portion 12 includes an annular block 27 provided to the end plate portion 24 and a cover 60 fixedly secured to the base plate portion 25. Therefore, the sealing surface 74b of the seal ring 71 constituting the second floating seal 18b slides with the cover 60. Although sliding, the second floating seal 18b seals the space between the output portion 13 and the cover 60.

[0089] The sealing surfaces 74b of the seal rings 71 of the first floating seal 18a and the third floating seal 18c also slide against each other. Although sliding, the first floating seal 18a and the third floating seal 18c seal the space between the output portion 13 and the end plate portion 24 (annular block 27).

[0090] As described above, the sealing device 70 includes the output portion 13 as the first component, the cover 60 as the second component, and the second floating seal 18b. The output portion 13 is provided with the second seal accommodation recess 17 having the inner peripheral surface 17b. The cover 60 is configured to rotate relative to the output portion 13 and to be opposite to the output portion 13 in the axial direction. The second floating seal 18b is accommodated in the second seal accommodation recess 17. The second floating seal 18b includes a sealing ring 71 and an O-ring 72. The sealing surface 74b of the sealing ring 71 is pressed toward the cover 60 by the O-ring 72. Thus, the sealing performance between the sealing ring 71 and the cover 60 is ensured.

[0091] Therefore, instead of using a pair of floating seals (seal rings 71) as in the prior art, the sealing device 70 can be configured using a single seal ring 71. This ensures high sealing performance and durability of the sealing device 70 and makes the sealing device 70 compact.

[0092] The cover 60 is attached to the fixing portion 12 as a third member provided to be rotatable relative to the output portion 13. The cover 60 constituting the speed reduction portion 3 also serves as a part of the sealing device 70. Therefore, the speed reduction portion 3 including the sealing device 70 can be miniaturized.

[0093] The first floating seal 18a and the second floating seal 18b are arranged radially in parallel with the corresponding bearings 23a and 23b. Therefore, the axial length of the speed reducing unit 3 can be shortened compared with the case where the floating seals 18a and 18b and the bearings 23a and 23b are arranged axially.

[0094] The sealing device 70 can be appropriately used in the structure of the speed reduction portion 3 .

[0095] The excavator 100 provided with the sealing device 70 has high sealing performance and can realize a compact and high-performance excavator 100 .

[0096] In the above-mentioned embodiment, the following case is described: the output part 13 is used as the first component, the cover 60 is used as the second component, and the sealing surface 74b of the sealing ring 71 is pressed toward the cover 60 by the O-ring 72, thereby ensuring the sealing between the sealing ring 71 and the cover 60. However, the present embodiment is not limited to such a case, and the first component and the second component can be combined in various ways. The following is a detailed description.

[0097] [First Modification]

[0098] Figure 4 It is a cross-sectional view showing a first modified example of the sealing device 70 according to the embodiment. Figure 4 With the aforementioned Figure 3 Corresponding.

[0099] like Figure 4 As shown in FIG. 1 , the second floating seal 18b may be installed in the opposite direction. In this case, the second seal housing recess 17 is not provided in the output portion 13, and a circular seal housing housing 62 is provided on one surface 60a of the cover 60 near the output portion 13. The seal housing housing 62 has an inner peripheral surface 62a. The inner peripheral surface 62a is inclined in a manner that the inner diameter gradually increases toward the output portion 13.

[0100] The seal ring 71 of the second floating seal 18b is disposed radially spaced apart from the inner peripheral surface 62a of the seal housing case 62. The O-ring 72 is disposed between the inner peripheral surface 62a of the seal housing case 62 and the tapered outer peripheral surface 73a of the seal ring 71.

[0101] In such a structure, the sealing surface 74b of the flange portion 74 is pressed toward the end surface 13c of the output portion 13 on the cover 60 side by the O-ring 72. That is, the output portion 13 becomes the second member, and the cover 60 becomes the first member. Even in the case of such a structure, the same effects as those of the above-mentioned embodiment are achieved.

[0102] [Second Modification]

[0103] Figure 5 It is a cross-sectional view showing a second modified example of the speed reduction portion 30 according to the embodiment.

[0104] In the above-mentioned embodiment, the case where the sealing device 70 is constituted by the second floating seal 18b and the cover 60 is described. However, the present invention is not limited to such an embodiment. Figure 5 As shown, the sealing device 70 may be constituted by the first floating seal 18 a provided on the side of the output portion 13 opposite to the cover 60 and the annular block 27 arranged to face the first floating seal 18 a in the axial direction.

[0105] In this case, the third seal housing recess 28 is not formed on the first end face 27a of the annular block 27, and the third floating seal 18c is not provided. In such a structure, the sealing surface 74b of the seal ring 71 is pressed toward the first end face 27a of the annular block 27 by the O-ring 72 of the first floating seal 18a. On the other hand, the annular block 27 presses the sealing surface 74b of the seal ring 71 from the axially outer side. That is, the output part 13 becomes the first component, and the end plate part 24 (annular block 27) becomes the second component. Thus, the output part 13 and the end plate part 24 (annular block 27) are sealed by the first floating seal 18a. The annular block 27 can also be said to be a cover that closes the first opening 13d of the output part 13 on the motor part 2 side. Therefore, according to the second modified example, the same effect as the aforementioned embodiment is achieved.

[0106] [Third Modification]

[0107] Figure 6 It is a cross-sectional view showing a third modified example of the speed reduction portion 30 according to the embodiment.

[0108] In the above-mentioned embodiment, the case where the speed reduction mechanism 14 of the speed reduction unit 30 is a so-called eccentric swing type speed reduction mechanism is described. The case where the eccentric swing type speed reduction mechanism has a plurality of (for example, three) crankshafts 42 arranged around the input shaft 41 is described. The case where the swing gears 43 and 44 are swung and rotated by the rotation of these crankshafts 42 is described. However, the present invention is not limited to such an embodiment. Figure 6 As shown, the input shaft 41 may be a center crankshaft 81. In this case, a connecting shaft 82 having no eccentric portions 42a, 42b is used instead of the crankshaft 42. The connecting shaft 82 connects the end plate body 26 and the base plate body 29.

[0109] The first eccentric portion 81a and the second eccentric portion 81b are formed at 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 arranged on the end plate body 26 side. The second eccentric portion 81b is arranged on the base plate body 29 side. Each eccentric portion 81a, 81b is eccentric with respect to the rotor rotation axis A1. The phase angles of the first eccentric portion 81a and the second eccentric portion 81b are offset from each other. The first swing gear 43 is rotatably supported on the first eccentric portion 81a by means of the first bearing 83. The second swing gear 44 is rotatably supported on the second eccentric portion 81b by means of the second bearing 84.

[0110] In such a structure, the center crankshaft 81 rotates integrally with the rotor shaft 10. The swing gears 43 and 44 swing and rotate with the rotation of the center crankshaft 81. Therefore, according to the third modification, the same effects as those of the above-mentioned embodiment are achieved.

[0111] In addition, in the third modification, the input gear 45 and the transmission gear 46 (see FIG. 4 ) for transmitting the rotational force to each crankshaft 42 as in the above-mentioned embodiment are not required. Figure 2 ). Therefore, it is not necessary to ensure a space for arranging the input gear 45 and the transmission gear 46 on the motor unit 2 side of the end plate body 26. Thus, the axial thickness of the annular block 27 can be reduced.

[0112] The sealing device 70 can be constituted by the annular block 27 and the first floating seal 18 a.

[0113] In the third modified example, the substrate portion 25 is formed integrally with the cover 60, and the cover 60 is provided with a third floating seal 18c. That is, a circular ring-shaped seal housing case 62 is provided on a surface 60a of the cover 60 on the side of the output portion 13. The third floating seal 18c is provided in the seal housing case 62. The installation direction of the third floating seal 18c is similar to the installation direction of the second floating seal 18b in the first modified example (see FIG. Figure 4 ) is the same. Therefore, the second floating seal 18b and the third floating seal 18c make their sealing surfaces 74b butt against each other. Thus, the output portion 13 and the cover 60 are sealed.

[0114] In the third modification, the case where the output portion 13 and the cover 60 are sealed using two floating seals 18b and 18c is described. However, the present invention is not limited to such a modification. The output portion 13 and the cover 60 may be sealed using the sealing device 70 (the second floating seal 18b and the cover 60) as in the above-mentioned embodiment.

[0115] The present invention is not limited to the above-described embodiment and modified examples. The present invention includes various modifications to the above-described embodiment within the scope of the present invention.

[0116] For example, in the above-mentioned embodiment, the excavator 100 is described as a construction machine. However, the present invention is not limited to such an embodiment. The structure of the above-mentioned embodiment and the modified example can be adopted in various construction machines having two components that can rotate relative to each other. In addition to the construction machine, the structure of the above-mentioned embodiment and the modified example can also be adopted in a drive device having two components that can rotate relative to each other.

[0117] In the above-mentioned embodiment, the case where the output part 13 is rotated relative to the fixed part 12 is described. However, the present invention is not limited to such an embodiment. The output part 13 may be fixed, and the fixed part 12 may be rotated relative to the output part 13. Furthermore, the member fixed to the fixed part 12 may be rotated around the rotor rotation axis A1.

[0118] In the above-mentioned embodiment, the case where the cover 60 is formed of the same material as the material of the sealing ring 71 of each floating seal 18a to 18c is described. However, the present invention is not limited to such an embodiment. The material of the cover 60 and the material of the sealing ring 71 may be different. Preferably, the rigidity of the cover 60 is the same as the rigidity of the sealing ring 71.

[0119] In the above-mentioned embodiment, the following case is described: the speed reduction mechanism 14 is an eccentric swing type speed reduction mechanism having a crankshaft 42 or a center crankshaft 81 and having swing gears 43 and 44. However, the present invention is not limited to such an embodiment. Various speed reduction mechanisms can be applied. For example, a planetary gear speed reduction mechanism can also be applied instead of the eccentric swing type speed reduction mechanism. As an alternative to the speed reduction mechanism, a speed increase mechanism that increases the speed of the rotation of the rotor shaft 10 and outputs it can also be used.

[0120] It may also be a transmission mechanism that neither reduces speed nor increases speed but merely transmits power. As an alternative to the speed reduction unit 3, a general rotating device may also be used.

[0121] In the above-described embodiment, the O-ring 72 is used as the elastic ring disposed on the tapered outer peripheral surface 73 a of the seal ring 71 . However, the present invention is not limited to such an embodiment. Instead of the O-ring 72 , an elastically deformable member may be used.

[0122] In the above-described embodiment, the cover 60 is fastened and fixed to the base plate portion 25 (base plate main body 29) by the bolts 61. However, the present invention is not limited to such an embodiment. The base plate portion 25 and the cover 60 may be integrally formed.

[0123] In the embodiments disclosed in this specification, a component composed of multiple objects may be integrated into one, or a component composed of one object may be divided into multiple objects. Regardless of whether the components are integrated or not, they may be configured in a manner that can achieve the purpose of the invention.

Claims

1. A sealing device, wherein: The sealing device has: A first member having an inner peripheral surface; a second member that rotates relative to the first member and is disposed so as to face the first member in a rotation axis direction; a seal ring having an outer peripheral surface radially opposed to the inner peripheral surface in a manner spaced apart from the inner peripheral surface, and having a sealing surface in contact with the second member in a manner sliding relative to the second member; as well as an elastic ring disposed between the inner peripheral surface of the first member and the outer peripheral surface of the seal ring and elastically deforming, The sealing surface of the sealing ring is pressed toward the second member by the elastic ring, so that a seal is formed between the sealing surface and the second member.

2. The sealing device according to claim 1, wherein: The sealing device includes a third member, the third member is accommodated in the first member and is provided to be rotatable relative to the first member. The first member is formed into a cylindrical shape having an opening. The second member is a cover provided to an end portion of the third member in the direction of the rotation axis. The cover closes the opening of the first member.

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

4. The sealing device according to claim 3, wherein: The sealing device includes a speed change mechanism connecting the first member and the third member. The speed change mechanism changes the speed of rotation of one of the first member and the third member and transmits the speed of rotation to the other of the first member and the third member.

5. The sealing device according to claim 1, wherein: The sealing device includes a third member, the third member is accommodated in the second member and is provided to be rotatable relative to the second member. The second member is formed into a cylindrical shape having an opening. The first member is a cover provided to an end portion of the third member in the direction of the rotation axis. The cover closes the opening of the second member. The sealing surface is pressed against an end portion of the second member in the rotation axis direction.

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

7. The sealing device according to claim 6, wherein: The sealing device includes a speed change mechanism connecting the second member and the third member. The speed change mechanism changes the speed of rotation of one of the second member and the third member and transmits the speed of rotation to the other of the second member and the third member.

8. A construction machine, wherein: The construction machine includes a vehicle body having a moving part provided with a sealing device. The sealing device comprises: A first member, which is shared with a portion of the operating portion and has an inner peripheral surface; a second member that rotates relative to the first member and is disposed so as to face the first member in the direction of the rotation axis and is shared with a portion of the operating portion; a seal ring having an outer peripheral surface radially opposed to the inner peripheral surface in a manner spaced apart from the inner peripheral surface, and having a sealing surface in contact with the second member in a manner sliding relative to the second member; as well as an elastic ring disposed between the inner peripheral surface of the first member and the outer peripheral surface of the seal ring and elastically deforming, The sealing surface of the sealing ring is pressed toward the second member by the elastic ring, so that a seal is formed between the sealing surface and the second member.

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