JP2017133560A - Swivel joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a swivel joint capable of reducing an axial dimension.SOLUTION: At a cylinder part 34 of a body 32, a cylinder part hydraulic oil passage 35 is provided. At a spindle 53, a cylinder opening hydraulic oil passage 58 communicating with the cylinder part hydraulic oil passage 35 is provided. At a bottom surface 45 of a bottom part 44 of the body 32, an annular projection part 46 projecting toward the spindle 53 is provided. At a lower end surface 53B of the spindle 53, an annular recessed part 61 into which the projection part 46 is inserted is provided. At the bottom part 44 of the body 32, a body side fuel supply passage 50 is provided in which one side opens to a lower surface 48 and the other side opens to an apex of the projection part 46. At the spindle 53, a spindle side fuel supply passage 63 is provided in which one side opens to the bottom part of the recessed part 61 and the other side opens to an upper end surface 53A of the spindle 53. Also, at the bottom part 44 of the body 32, a mixture recovery passage 52 is provided in which one side opens to the lower surface 48 and the other side opens to both an outer peripheral surface and an inner peripheral surface of the projection part 46.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a swivel joint used as a center joint of a construction machine such as a hydraulic excavator or a hydraulic crane.

  For example, a hydraulic excavator as a construction machine includes a lower traveling body (fixed side base) having a crawler belt or wheels, and an upper revolving body (rotating side base) mounted on the lower traveling body via a swivel device so as to be able to swivel. ) And a front device (working device) provided at the front portion of the upper swing body so as to be able to move up and down. Further, a swivel joint called a center joint is provided between the lower traveling body and the upper swing body so as to be positioned on the swing center side of the swing device.

  The swivel joint supplies and discharges pressure oil (hydraulic oil) between the hydraulic power source on the upper revolving unit side and the traveling hydraulic motor on the lower traveling unit side even when the upper revolving unit is revolving on the lower traveling unit. (Return) is permitted, and fuel supply and discharge (return) are permitted between the engine on the upper swing body side and the fuel tank on the lower traveling body side (Patent Document 1).

  The swivel joint of Patent Document 1 includes a plurality of hydraulic oil passages (for example, a brake passage, a traveling hydraulic motor passage, a suspension cylinder passage, and the like) for flowing hydraulic oil between the upper swing body and the lower traveling body. Pilot signal passage) and a plurality of fuel passages (for example, fuel supply passage, fuel recovery passage) for distributing fuel between the fuel tank of the lower traveling body and the engine of the upper-part turning body, A liquid recovery passage is provided. The different liquid recovery passage is for recovering the hydraulic oil leaked from the hydraulic oil passage and the fuel leaked from the fuel passage in the swivel joint. Therefore, the different liquid recovery passage is provided between the annular groove for the hydraulic oil passage and the annular groove for the fuel passage which are adjacent in the axial direction.

  The hydraulic oil leaked from the annular groove for the hydraulic oil passage flows into the annular groove for the different liquid recovery passage, and the fuel leaked from the annular groove for the fuel passage flows into the annular groove for the different liquid recovery passage. The dissimilar liquid recovery passage is connected to a recovery tank provided separately from the fuel tank and the hydraulic oil tank. The hydraulic oil and fuel that have flowed into the different liquid recovery passage are collected in the recovery tank as a mixed liquid in the different liquid recovery passage. Thereby, it can suppress that a fuel mixes in the hydraulic fluid of a hydraulic oil path | route, and that a hydraulic oil mixes in the fuel of a fuel path | route.

  On the other hand, Patent Document 2 describes a configuration in which a main fuel tank is provided in a lower traveling body and a sub fuel tank is provided in an upper swing body. According to the configuration of Patent Document 2, surplus fuel (overflow fuel) in the engine of the upper swing body can be stored in the sub fuel tank of the upper swing body. For this reason, the fuel recovery passage for returning the overflow fuel from the upper swing body side to the main fuel tank on the lower traveling body side can be omitted from the swivel joint.

JP 2010-266003 A JP 2010-236287 A (Patent No. 5268747)

  In the swivel joint of Patent Document 1, a plurality of hydraulic oil passages, a plurality of fuel passages, and a plurality of different liquid recovery passages are arranged side by side in the axial direction of the swivel joint. For this reason, the axial direction dimension of a swivel joint increases, for example, the difficulty of swivel joint processing may become high. In addition to this, there is a possibility that the assembly workability (easiness of assembly) is lowered, the vehicle body mountability (mounting freedom) is lowered, and the like.

  The objective of this invention is providing the swivel joint which can reduce an axial direction dimension.

  The swivel joint of the present invention has a cylindrical and bottomed body provided with a spindle insertion hole and having a cylinder part and a bottom part, and is inserted into the spindle insertion hole of the body so as to be relatively rotatable about the axis of the rotation axis. A cylindrical or cylindrical spindle, a first body side passage having one side opened to the outer surface of the cylindrical portion of the body and the other side opened to the inner surface of the spindle insertion hole, and one side being the outer surface of the spindle A first spindle side passage that opens to a position corresponding to the first body side passage and the other side opens to the outer surface of the spindle at a position different from the position corresponding to the first body side passage.

  In order to solve the above-described problem, a feature of the configuration adopted by the present invention is that an annular protrusion provided on the bottom surface of the body facing the spindle and protruding from the bottom surface toward the spindle. And an annular recessed portion provided in a portion of the spindle that faces the bottom surface of the bottom portion of the body, the protrusion of the bottom portion being inserted so as to be relatively rotatable, and one side of the bottom portion of the body. A second body-side passage that opens to the bottom of the body on a surface different from the bottom surface and the outer surface of the protrusion, the other side opens to the top of the protrusion, and one side is the bottom of the recess of the spindle. A second spindle side passage that opens to a position corresponding to the second body side passage and the other side opens at a position different from the first spindle side passage on the outer surface of the spindle; A third surface opened to the bottom of the body on a surface different from the bottom surface of the protrusion and the outer surface of the protrusion, and the other side opened to the outer peripheral surface of the protrusion through a different position from the second body-side passage. The body side passage is provided.

  The swivel joint of the present invention can reduce the axial dimension. Thereby, for example, it is possible to reduce the difficulty of processing, facilitate assembly work, and improve vehicle body mountability (mounting freedom).

It is a front view showing a wheel type hydraulic excavator equipped with a center joint (swivel joint) according to an embodiment. It is a circuit diagram which shows a center joint and the various pipe lines connected to this. It is a longitudinal cross-sectional view which shows a center joint. It is a longitudinal cross-sectional view which cut | disconnects and shows a center joint in the circumferential direction position different from FIG. It is sectional drawing which expands and shows the (V) part in FIG. It is sectional drawing which expands and shows the (VI) part in FIG. The disassembled perspective view which shows the protrusion part of a body and the recessed part of a spindle. It is sectional drawing of the same position as FIG. 5 which shows the center joint by a modification.

  Hereinafter, the embodiment of the swivel joint according to the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the swivel joint is applied to a center joint of a wheel type hydraulic excavator.

  1 to 7 show an embodiment. In FIG. 1, a wheel-type hydraulic excavator 1 as a representative example of a construction machine (work machine, work vehicle) includes a lower traveling body 2 that can travel with front wheels 4 and rear wheels 5 that are wheels, and the lower traveling body 2. The upper revolving unit 10 is mounted on the upper revolving unit 10 so as to be able to revolve through the revolving unit 9, and the work device 21, also called a front device, is provided at the front portion of the upper revolving unit 10 so as to be able to move up and down. Yes.

  Here, the lower traveling body 2 and the upper swing body 10 constitute a vehicle body of the wheeled hydraulic excavator 1. The wheel-type hydraulic excavator 1 can travel on a public road by a wheel-type lower traveling body 2 and travel to a work site, and can perform excavation work of earth and sand using the work device 21 at the work site.

  The lower traveling body 2 includes a chassis 3, left and right front wheels 4 (only the left side is illustrated), left and right rear wheels 5 (only the left side is illustrated), a traveling hydraulic motor (not illustrated), a main fuel. A tank 7 and a recovery tank 8 (see FIG. 2) are included. The chassis 3 is a base of the lower traveling body 2 and extends in the front and rear directions of the vehicle body. A front axle housing (both not shown) is supported on the front side of the chassis 3 via, for example, a front suspension device including a suspension spring and a suspension cylinder. A rear axle housing (both not shown) is supported on the rear side of the chassis 3 via a rear suspension device constituted by a suspension spring and a suspension cylinder.

  A traveling hydraulic motor (not shown) is attached below the middle portion of the chassis 3. The traveling hydraulic motor is constituted by, for example, a variable displacement hydraulic motor that can be switched between a low speed and a high speed. Propeller shafts 6 and 6 extend from the traveling hydraulic motor toward the front axle housing and the rear axle housing, respectively. The propeller shaft 6 extending to the front side rotates the front wheel 4 via a front axle (not shown) rotatably supported by the front axle housing. The propeller shaft 6 extending to the rear side rotates the rear wheel 5 via a rear axle (not shown) rotatably supported by the rear axle housing.

  The front wheel 4 or the front axle is provided with a brake device (not shown) that applies a braking force to the front wheel 4, and the rear wheel 5 or the rear axle is a brake device that applies a braking force to the rear wheel 5 ( (Not shown) is provided. Further, a main fuel tank 7 for storing the fuel of the engine 15 is attached to the left side of the middle portion of the chassis 3. Further, as shown in FIG. 2, a recovery tank 8 for storing a mixed liquid of fuel and hydraulic oil recovered by a center joint 31 described later is attached to the chassis 3, in addition to the main fuel tank 7. .

  As shown in FIG. 2, the chassis 3 is provided with a center joint insertion hole 3 </ b> A through which a center joint 31 described later is inserted. The chassis 3 is provided with a center joint support cylinder 3B that supports the center joint 31 so as to surround the center joint insertion hole 3A. The flange portion 43 of the body 32 of the center joint 31 is fixed to the center joint support cylinder 3B using a plurality of bolts 3C. Thereby, the body 32 of the center joint 31 is integrally coupled to the lower traveling body 2.

  On the other hand, the upper swing body 10 is mounted on the lower traveling body 2 via the swing device 9. The turning device 9 includes, for example, a turning hydraulic motor, a speed reduction mechanism, a turning bearing, and the like. The upper turning body 10 is driven to turn with respect to the lower traveling body 2 by the turning device 9. Further, a center joint 31 is provided between the lower traveling body 2 and the upper swinging body 10 so as to be positioned on the turning center side of the swinging device 9.

  In this case, the axis of the center joint 31 (rotation center axis OO) is concentric with the axis of the slewing bearing of the swivel device 9 (rotation center axis OO). As will be described later, the center joint 31 supplies the hydraulic oil between the upper swing body 10 side and the lower travel body 2 side even when the upper swing body 10 is swinging on the lower travel body 2. It is configured to allow discharge (return) and fuel supply and discharge (return).

  The upper swing body 10 includes a swing frame 11, a counterweight 13, a cab 14, a building cover 15, an engine 16, a hydraulic pump 18 (see FIG. 2), a control valve 20 (see FIG. 2), and the like, which will be described later. Yes. The turning frame 11 is a frame that forms a support structure of the upper turning body 10. The turning frame 11 is attached to the chassis 3 of the lower traveling body 2 via the turning device 9.

  As shown in FIG. 2, the turning frame 11 is provided with a center joint insertion hole 11 </ b> A that is located on the turning center side and through which the center joint 31 is inserted. The revolving frame 11 is provided with a center joint support bracket 11B that supports the center joint 31 adjacent to the center joint insertion hole 11A. The upper part of the spindle 53 of the center joint 31 is fixed to the center joint support bracket 11B using a plurality of bolts 11C. Thereby, the spindle 53 of the center joint 31 is integrally coupled to the upper swing body 10.

  A current collector 12 is attached to the upper side of the center joint support bracket 11B. The current collector 12 is positioned above center holes 49 and 54 provided in the body 32 and the spindle 53 of the center joint 31, respectively. The current collector 12 includes, for example, a slip ring that serves as a stator and a sliding brush (both not shown) that serves as a rotor. In this case, for example, an electric device (not shown) on the upper swing body 10 side is connected to the slip ring via the upper cable 12A, and an electric device (not shown) on the lower traveling body 2 side is connected to the sliding brush. Are connected via the lower cable 12B.

  In this case, the lower cable 12 </ b> B is connected to the sliding brush of the current collector 12 through the center holes 49 and 54 of the center joint 31. When the upper turning body 10 turns on the lower traveling body 2, the slip ring of the current collector 12 and the sliding brush rotate relative to each other while sliding. Thereby, relative rotation is permitted between the upper cable 12A and the lower cable 12B, and the electric device on the upper revolving unit 10 side and the electric device on the lower traveling unit 2 side regardless of the turning operation of the upper revolving unit 10 Can be maintained.

  On the other hand, as shown in FIG. 1, a counterweight 13 for balancing the weight with the work device 21 is provided on the rear side of the revolving frame 11. A cab 14 that defines a driver's cab is provided on the left front side of the swivel frame 11. In the cab 14, a driver's seat where an operator is seated, a handle for steering the front wheels 4 of the lower traveling body 2, a brake pedal for operating a brake, an accelerator pedal for operating an accelerator, and a work device 21 are operated. An operation lever device or the like (none of which is shown) is provided. The building cover 15 is disposed on the front side of the counterweight 13 and defines a machine room that houses mounted devices such as the engine 16 and the hydraulic pump 18.

  The engine 16 is located on the front side of the counterweight 13 and is mounted on the rear side of the turning frame 11. The engine 16 is configured using, for example, a diesel engine, and serves as a power source for the hydraulic pump 18. As shown in FIG. 2, fuel is supplied to the engine 16 from the main fuel tank 7 of the lower traveling body 2 through the center joint 31. In this case, a sub fuel tank 17 is provided between the center joint 31 and the engine 16 for temporarily storing fuel on the upper swing body 10 side.

  The sub fuel tank 17 and the engine 16 return, for example, a supply pipe 17 </ b> A for supplying fuel from the sub fuel tank 17 to the engine 16 and fuel (overflow fuel) surplus in the engine 16 to the sub fuel tank 17. And a return line 17B. In FIG. 2, the engine 16 and the sub fuel tank 17 are disposed apart from each other, but the sub fuel tank 17 may be provided integrally with the engine 16.

  The hydraulic pump 18 constitutes a hydraulic pressure source together with the hydraulic oil tank 19 (see FIG. 2). The hydraulic pump 18 is driven by the engine 16 to draw hydraulic oil from the hydraulic oil tank 19 and supplies the drawn hydraulic oil to the control valve 20 as pressure oil.

  The control valve 20 is switched according to a pilot pressure (pilot signal) supplied via an operation lever device or the like in the cab 14. The control valve 20 applies pressure oil discharged from the hydraulic pump 18 to the cylinders 21D, 21E, and 21F of the work device 21, the turning hydraulic motor of the turning device 9, and the lower traveling body according to the operation of the operation lever device or the like. And selectively supplying or discharging various hydraulic actuators including the two traveling hydraulic motors.

  As shown in FIG. 1, the work device 21 is provided on the front side of the revolving frame 11. The work device 21 includes a boom 21A attached to the front side of the revolving frame 11 so as to be able to move up and down, an arm 21B rotatably attached to the distal end side of the boom 21A, and a rotation toward the distal end side of the arm 21B. It includes a bucket 21C as a work tool movably attached, a boom cylinder 21D and an arm cylinder 21E for driving them, and a bucket cylinder 21F as a work tool cylinder.

  Next, various pipe lines connected to the center joint 31 will be described with reference to FIG. In FIG. 2, in order to avoid complication of the drawing, for example, one pipe is shown for a pair of (two) or more pipes for supply and discharge (return). Some have. That is, FIG. 2 does not strictly represent all the pipes connected to the center joint 31. Further, in FIG. 2, since the respective pipelines are shown to overlap each other, the connection position between each pipeline and the center joint 31 does not strictly correspond to the actual connection position. That is, FIG. 2 schematically shows the configuration of the center joint 31 and various pipe lines connected thereto.

  As will be described later, regardless of the turning motion of the upper swing body 10, the center joint 31 has a hydraulic oil between the body 32 fixed to the lower traveling body 2 and the spindle 53 fixed to the upper swing body 10. Delivery and delivery of fuel can be performed. Here, for example, an upper hydraulic oil line 22A, an upper pilot line 23A, an upper drain line 24A, an upper brake line 25A, an upper suspension line 26A, and the like are connected to the spindle 53 on the upper swing body 10 side. Yes. On the other hand, for example, a lower hydraulic oil line 22B, a lower pilot line 23B, a lower brake line 25B, a lower suspension line 26B, and the like are connected to the cylindrical portion 34 of the body 32 on the lower traveling body 2 side. ing. A lower drain conduit 24B is connected to the bottom 44 of the body 32 on the lower traveling body 2 side.

  The upper hydraulic oil line 22A and the lower hydraulic oil line 22B connect, for example, the control valve 20 of the upper swing body 10 and the traveling hydraulic motor of the lower traveling body 2. That is, supply and discharge (return) of pressure oil between the control valve 20 and the traveling hydraulic motor are performed through the upper hydraulic oil line 22A, the center joint 31, and the lower hydraulic oil line 22B.

  The upper pilot line 23A and the lower pilot line 23B connect, for example, an operation lever device (low speed, high speed switching lever device) in the cab 14 and a displacement control valve of a traveling hydraulic motor. That is, the pilot pressure for the low speed and high speed switching signal for the traveling hydraulic motor is supplied to the displacement control valve of the traveling hydraulic motor through the upper pilot line 23A, the center joint 31, and the lower pilot line 23B.

  The upper drain conduit 24A and the lower drain conduit 24B connect, for example, the hydraulic oil tank of the upper swing body 10 and the drain chamber of the traveling hydraulic motor and / or the variable capacity actuator of the traveling hydraulic motor. . That is, the oil liquid (drain) leaked from the traveling hydraulic motor and / or the oil liquid flowing out of the variable capacity actuator is supplied to the hydraulic oil tank 19 through the lower drain line 24B, the center joint 31, and the upper drain line 24A. Discharged.

  The upper brake line 25A and the lower brake line 25B are, for example, a brake valve (not shown) on the upper swing body 10 side that supplies pressure oil according to an operator's brake operation and a brake device on the lower traveling body 2 side. (Brake cylinder). That is, the brake pressure based on the brake operation by the operator is supplied to the brake device (brake cylinder) through the upper brake line 25A, the center joint 31, and the lower brake line 25B.

  The upper suspension pipe 26A and the lower suspension pipe 26B are, for example, a suspension valve (not shown) on the upper swing body 10 that is switched between running and working of the wheeled hydraulic excavator 1 and the lower running body 2 side. The suspension device (suspension cylinder) is connected. For example, during traveling, the pressure oil required for the suspension device is supplied to the suspension device through the upper suspension pipe 26A, the center joint 31, and the lower suspension pipe 26B. On the other hand, during operation, for example, the supply of pressure oil to the suspension device is cut off by the suspension valve, and the suspension cylinder of the suspension device is prevented from extending or contracting.

  Further, an upper fuel supply line 27A and an upper fuel recovery line 28A are connected to the spindle 53 of the center joint 31. On the other hand, a lower fuel supply conduit 27B, a lower fuel recovery conduit 28B, and a mixed liquid recovery conduit 29 are connected to the bottom 44 of the body 32 of the center joint 31.

  The upper fuel supply line 27A and the lower fuel supply line 27B connect the sub fuel tank 17 on the upper swing body 10 side and the main fuel tank 7 on the lower traveling body 2 side. That is, the fuel supplied from the main fuel tank 7 to the engine 16 is supplied through the lower fuel supply conduit 27B, the center joint 31, the upper fuel supply conduit 27A, and the sub fuel tank 17.

  The upper fuel recovery line 28A and the lower fuel recovery line 28B connect the sub fuel tank 17 on the upper swing body 10 side and the main fuel tank 7 on the lower traveling body 2 side. That is, excess fuel (overflow fuel) in the sub fuel tank 17 returns to the main fuel tank 7 through the upper fuel recovery line 28A, the center joint 31, and the lower fuel recovery line 28B.

  The mixed liquid recovery conduit 29 connects the center joint 31 and the recovery tank 8. That is, the mixed liquid of the fuel and the hydraulic oil recovered by the center joint 31 is recovered from the center joint 31 to the recovery tank 8.

  Incidentally, the swivel joint of Patent Document 1 includes a plurality of hydraulic oil passages through which hydraulic oil flows, a plurality of fuel passages through which fuel flows, and a plurality of different liquid recovery passages through which a mixed liquid of fuel and hydraulic oil flows. Are arranged side by side in the axial direction of the swivel joint. For this reason, the axial direction dimension of a swivel joint increases. In this case, for example, when manufacturing a swivel joint, the difficulty of processing the spindle and the body is increased. That is, in order to suppress the swing of the spindle and the body shaft, it is necessary to ensure the concentricity and cylindricity of the spindle and the body. However, as the axial dimension becomes longer, it is troublesome to ensure the concentricity and cylindricity, and the difficulty of processing increases.

  Further, as the axial dimension becomes longer, the weight of the spindle and the body increases accordingly. For this reason, for example, when assembling the spindle and the body, there is a possibility that the work burden (force required for the work) of the transportation and the posture change increases. Thereby, it is troublesome to perform fine position adjustment and the like, and assembly workability (easy assembly) may be reduced. Moreover, it is necessary to attach a seal member from the opening side of the body into the spindle insertion hole of the body. In this case, the distance between the part to which the seal member is attached and the opening becomes long, and the attachment workability (easy attachment) of the seal member may be reduced accordingly.

  Furthermore, when the swivel joint is mounted on the vehicle body, the space occupied by the swivel joint is increased, and the vehicle body mountability (mounting freedom) may be reduced. Further, when mounted on the vehicle body, the distance between the members around the swivel joint and the swivel joint is narrowed, and for example, the degree of freedom in handling the hose may be reduced.

  On the other hand, the center joint 31 of the embodiment can shorten the axial dimension. Therefore, the center joint 31 according to the embodiment will be described with reference to FIGS. 3 to 7 in addition to FIGS. In the following description, one end side in the axial direction of the center joint 31 is defined as the upper end side (upper and lower end sides in FIGS. 1 to 7), and the other end side in the axial direction is defined as the lower end side (see FIGS. 7), the lower end side in the upper and lower directions).

  The center joint 31 as a swivel joint includes a cylindrical and bottomed body 32 and a cylindrical spindle 53. In this case, the body 32 includes a plurality (four) of cylinder portion hydraulic oil passages 35, a single (one) bottom hydraulic oil passage 47, a single (one) body-side fuel supply passage 50, and a single ( 1) a body-side fuel recovery passage 51 and a single (one) mixed liquid recovery passage 52. The spindle 53 has a plurality of (four) cylinder opening hydraulic oil passages 58 that are paired with the cylinder portion hydraulic oil passage 35 and a single (one) bottom opening that is paired with the bottom portion hydraulic oil passage 47. A single (one) spindle side fuel supply passage 63 that forms a pair with the hydraulic oil passage 60, the body side fuel supply passage 50, and a single (one) spindle side that forms a pair with the body side fuel recovery passage 51. And a fuel recovery passage 64.

  Each cylinder section hydraulic oil passage 35 of the body 32 and each cylinder opening hydraulic oil path 58 of the spindle 53 communicate with each other through a cylinder-side annular groove 36 of the cylinder section 34 of the body 32, and Hydraulic oil circulates. For example, a lower hydraulic oil line 22B, a lower pilot line 23B, a lower brake line 25B, and a lower suspension line 26B are connected to each cylindrical portion hydraulic oil path 35 of the body 32, respectively. On the other hand, for example, a lower hydraulic oil line 22B, a lower pilot line 23B, a lower brake line 25B, and a lower suspension line 26B are connected to each cylinder opening hydraulic oil path 58 of the spindle 53.

  The bottom hydraulic fluid passage 47 of the body 32 and the bottom opening hydraulic fluid passage 60 of the spindle 53 communicate with each other via a large-diameter annular chamber 57 between the bottom surface 45 of the bottom portion 44 of the body 32 and the lower end surface 53B of the spindle 53. And hydraulic oil circulates. The lower drain conduit 24 </ b> B is connected to the bottom hydraulic fluid passage 47 of the body 32, and the upper drain conduit 24 </ b> A is connected to the bottom opening hydraulic fluid passage 60 of the spindle 53.

  The body-side fuel supply passage 50 and the spindle-side fuel supply passage 63 communicate with each other via a small-diameter annular chamber 62 between the top of the projecting portion 46 of the body 32 and the bottom of the recessed portion 61 of the spindle 53. Circulate. A lower fuel supply line 27B is connected to the body side fuel supply passage 50, and an upper fuel supply line 27A is connected to the spindle side fuel supply path 63.

  The body side fuel recovery passage 51 and the spindle side fuel recovery passage 64 communicate with each other via a fuel recovery outer annular groove 66 of the recessed portion 61 of the spindle 53 so that fuel flows. A lower fuel recovery line 28B is connected to the body side fuel recovery passage 51, and an upper fuel recovery line 28A is connected to the spindle side fuel recovery path 64.

  The mixed liquid recovery passage 52 communicates with a mixed liquid recovery outer annular groove 68 and a mixed liquid recovery inner annular groove 69 provided in the recessed portion 61 of the spindle 53. The mixed liquid recovery outer annular groove 68 recovers fuel leaked downward from the outer intermediate seal member 72 and hydraulic oil leaked upward from the outer lower seal member 73. The mixed liquid recovery inner annular groove 69 recovers the fuel leaked downward from the inner intermediate seal member 76. In the mixed liquid recovery passage 52, a mixed liquid of recovered fuel and hydraulic oil flows. A mixed liquid recovery conduit 29 is connected to the mixed liquid recovery passage 52.

  Here, the body 32 is provided with a spindle insertion hole 33 through which the spindle 53 is rotatably inserted. For this purpose, the body 32 has a cylindrical portion 34 which is formed in a cylindrical shape and whose inner diameter side is a spindle insertion hole 33, and an opening on the lower end side which is one end side in the axial direction (upward and downward direction) of the cylindrical portion 34. The bottom portion 44 is closed. In the embodiment, the cylindrical portion 34 and the bottom portion 44 are formed separately. In this case, for example, the cylindrical portion 34 can be made of cast iron, and the bottom portion 44 can be made of a material that hardly rusts (for example, a steel material such as stainless steel, a non-ferrous metal such as an aluminum alloy, a synthetic resin, or the like). The reason why the bottom portion 44 is made of a material that does not easily rust is that fuel that easily contains moisture flows through the body-side fuel supply passage 50, the body-side fuel recovery passage 51, and the mixed liquid recovery passage 52 of the bottom portion 44. Thereby, it can suppress that rust mixes in fuel.

  The cylindrical portion 34 of the body 32 is provided with four cylindrical portion hydraulic oil passages 35 each serving as a first body-side passage as a through hole penetrating the cylindrical portion 34 in the radial direction. The four cylinder part hydraulic oil passages 35 are arranged separately from each other in the axial direction of the cylinder part 34. The cylinder portion hydraulic oil passage 35 has one side opened to the outer surface of the cylinder portion 34 and the other side opened to the inner surface of the spindle insertion hole 33. In this case, on the inner surface of the spindle insertion hole 33, a cylinder-side annular groove 36 is provided at a position corresponding to the other side of each cylinder portion hydraulic oil passage 35 and is recessed radially outward over the entire circumference. Each cylinder-side annular groove 36 always (always) communicates the cylinder portion hydraulic oil passage 35 and the cylinder opening hydraulic oil passage 58 regardless of the relative rotation between the body 32 and the spindle 53.

  On the inner surface of the spindle insertion hole 33, a sealing annular groove 37 that is recessed radially outward is provided so as to sandwich each cylinder-side annular groove 36 in the axial direction. A seal member 38 made of an elastic material, also called a seal ring or an O-ring, is fitted into the seal annular groove 37. The seal member 38 seals between the inner surface of the spindle insertion hole 33 (the inner peripheral surface of the cylindrical portion 34) and the outer peripheral surface of the spindle 53. That is, the seal member 38 is configured so that the hydraulic oil in each cylinder-side annular groove 36 (hydraulic oil flowing through each cylinder portion hydraulic oil passage 35 and each cylinder opening hydraulic oil path 58) passes between the inner surface of the spindle insertion hole 33 and the spindle 53. Leakage in the axial direction (for example, the adjacent cylinder-side annular groove 36) between the outer peripheral surface and the outer peripheral surface is suppressed.

  On both end sides (upper end side and lower end side) of the spindle insertion hole 33 in the axial direction, an upper bush 39A and a lower bush 39B for supporting the spindle 53 rotatably in the spindle insertion hole 33 are provided. Further, on the upper end side of the spindle insertion hole 33, an upper sealing annular groove 40 that is recessed radially outward is provided in a portion where the inner diameter dimension is larger than other portions. The upper seal annular groove 40 has a seal member (dust seal) 41 for preventing hydraulic fluid from leaking to the outside of the center joint 31 and preventing foreign matter from entering the center joint 31. It is inserted.

  Further, a small-diameter portion 42 having a smaller outer diameter than the other portions is provided on the upper end side of the cylindrical portion 34. A flange portion 43 (see FIG. 2) for attaching the body 32 to the center joint support cylinder 3B is fixed to the small diameter portion. The flange portion 43 may be formed integrally with the cylindrical portion 34.

  On the other hand, the bottom portion 44 of the body 32 closes the opening on the lower end side of the cylindrical portion 34. The bottom portion 44 is fixed to the cylindrical portion 34 using, for example, a bolt (not shown). An annular protrusion 46 centering on the axis OO is provided on the bottom surface 45 of the bottom 44 facing the spindle 53. The protruding portion 46 protrudes from the bottom surface 45 toward the spindle 53. As shown in FIG. 4, the bottom portion 44 is provided with a bottom hydraulic oil passage 47 serving as a fourth body side passage as a through-hole penetrating upward and downward at a position radially outward from the protruding portion 46. It has been. That is, the bottom hydraulic fluid passage 47 opens to the bottom 44 of the body 32 at the lower surface 48 that is the lower end surface of the bottom 44 on one side and opens to the position on the other side of the bottom 45 that is radially outward from the protruding portion 46. ing.

  A central hole 49 penetrating between the bottom surface 45 and the lower surface 48 of the bottom portion 44 is provided on the center side of the bottom portion 44, that is, on the radially inner side of the protruding portion 46. As shown in FIG. 2, the lower cable 12 </ b> B that connects the electric device on the lower traveling body 2 side and the current collector 12 is inserted into the center hole 49.

  A body side fuel supply passage 50 as a second body side passage is provided in the bottom portion 44 of the body 32 as a through-hole penetrating upward and downward between the lower surface 48 of the bottom portion 44 and the top portion of the protruding portion 46. It has been. As a result, the body side fuel supply passage 50 has one side opened to the bottom 44 of the body 32 at the lower surface 48 of the bottom 44, and the other side opened to the top (more specifically, the top and tip surfaces) of the protrusion 46. doing. In the embodiment, the lower surface 48 of the bottom portion 44 corresponds to a surface different from the bottom surface 45 of the bottom portion 44 and the outer surface of the protruding portion 46.

  In addition, a body-side fuel recovery passage 51 serving as a fifth body-side passage is provided at the bottom 44, and a bottom surface 48 of the bottom 44 and a side surface of the protrusion 46 (specifically, an outer peripheral surface and an inner peripheral surface of the protrusion 46. ) Are provided as through-holes. In this case, the body-side fuel recovery passage 51 has a lateral through hole 51A penetrating between the inner peripheral surface and the outer peripheral surface of the projecting portion 46, and a vertical penetrating through between the lower surface 48 of the bottom portion 44 and the lateral through hole 51A. It has a through hole 51B. As a result, the body-side fuel recovery passage 51 has one side that opens to the bottom 44 of the body 32 at the lower surface 48 of the bottom 44 and the other side that passes through a position different from the body-side fuel supply passage 50 and the inner peripheral surface of the protrusion 46. Open to the outer peripheral surface.

  Further, a mixed liquid recovery passage 52 as a third body side passage is provided in the protrusion 46, and a bottom surface 48 of the bottom portion 44 and a side surface of the protrusion 46 (specifically, the outer peripheral surface and the inner peripheral surface of the protrusion 46. ) Are provided as through-holes. In this case, the mixed liquid recovery passage 52 includes a lateral through hole 52A penetrating between the inner peripheral surface and the outer peripheral surface of the protrusion 46 below the lateral through hole 51A of the body side fuel recovery passage 51, and the body side. There is a vertical through hole 52B penetrating between the lower surface 48 of the bottom portion 44 and the horizontal through hole 52A at a position different from the vertical through hole 51B of the fuel recovery passage 51 (a position deviated in the circumferential direction of the protrusion 46). ing. As a result, the mixed liquid recovery passage 52 projects from one side to the bottom 44 of the body 32 at the lower surface 48 of the bottom 44 and the other side through a position different from the body side fuel supply passage 50 and the body side fuel recovery passage 51. It opens to both the outer peripheral surface and the inner peripheral surface of the portion 46.

  On the other hand, the spindle 53 is inserted into the spindle insertion hole 33 of the body 32 so as to be relatively rotatable around the axis OO of the rotation axis. Since the fuel flows through a spindle-side fuel supply passage 63 and a spindle-side fuel recovery passage 64, which will be described later, the spindle 53 is made of a material that is not easily rusted (for example, a steel material such as stainless steel or a non-ferrous metal such as an aluminum alloy). , Synthetic resin, etc.). Thereby, it can suppress that rust mixes in fuel.

  At the center of the spindle 53, a center hole 54 is provided that passes between an upper end surface 53A that is one end surface of the spindle 53 and a lower end surface 53B that is the other end surface. The lower cable 12B is inserted into the center hole 54 of the spindle 53 in the same manner as the center hole 49 of the bottom portion 44. On the upper end side of the spindle 53, a screw hole 55 into which a bolt 11C for fixing the spindle 53 and the center joint support bracket 11B is screwed is provided.

  A ring member 56A is attached to the lower end side of the spindle 53 via a retaining ring 56B. The ring member 56 </ b> A serves as a sliding member that prevents the spindle 53 from being displaced downward with respect to the body 32 and allows relative rotation between the bottom portion 44 of the body 32 and the spindle 53. As a result, the outer diameter side of the protruding portion 46 between the bottom surface 45 of the bottom portion 44 of the body 32 and the lower end surface 53B of the spindle 53 is a large-diameter annular chamber 57 into which hydraulic oil enters. In the large-diameter annular chamber 57, hydraulic oil leaked downward from the seal member 38 between the inner peripheral surface of the cylindrical portion 34 and the outer peripheral surface of the spindle 53, and the bottom hydraulic fluid passage 47 and the bottom opening hydraulic fluid. The hydraulic oil flowing through the passage 60 enters. The large-diameter annular chamber 57 serves as an oil chamber for always communicating the bottom hydraulic fluid passage 47 and the bottom opening hydraulic fluid passage 60. The hydraulic oil in the large-diameter annular chamber 57 also serves to lubricate the lower bush 39B and the ring member 56A.

  The spindle 53 is provided with four cylinder opening hydraulic oil passages 58 each serving as a first spindle side passage. Each cylinder opening hydraulic oil passage 58 is, for example, a bottomed vertical hole 58A that extends in the axial direction of the spindle 53 and opens to the upper end surface 53A of the spindle 53, and an outer surface (outer peripheral surface) of the spindle 53 that is above the body 32. The upper end side horizontal through hole 58B penetrating between the part projecting to the (one side) and the vertical hole 58A, and the part inserted into the body 32 and the vertical hole 58A on the outer surface (outer peripheral surface) of the spindle 53 are penetrated. And a lower end side lateral through hole 58C.

  58 C of lower end side horizontal through-holes of each cylinder opening hydraulic oil path 58 are each provided according to the height position (upper and lower position) of each cylinder part hydraulic oil path 35 used as a pair. Furthermore, the upper end opening of the vertical hole 58A is closed by a plug 59, for example. As a result, each cylinder opening hydraulic fluid passage 58 opens on the outer surface of the spindle 53 at a position corresponding to each cylinder hydraulic fluid passage 35 of the body 32 (the cylindrical portion 34 thereof), and the other side of each cylinder hydraulic fluid passage 58. An opening is formed on the outer surface of the spindle 53 at a position different from the position corresponding to the passage 35. In this case, the other side of each cylinder opening hydraulic fluid passage 58 opens to a portion of the outer surface of the spindle 53 that protrudes upward (one side) from the body 32.

  A bottom opening hydraulic fluid passage 60 serving as a fourth spindle-side passage penetrates between the upper end surface 53A and the lower end surface 53B of the spindle 53 at a position radially outside the later-described recessed portion 61 of the spindle 53. It is provided as a through hole. In this case, the bottom opening hydraulic fluid passage 60 penetrates between the vertical hole 60A extending in the axial direction of the spindle 53 and a portion of the outer surface (outer peripheral surface) of the spindle 53 protruding above the body 32 and the vertical hole 60A. And a horizontal through hole 60B. The upper end opening of the vertical hole 60A is closed by a plug 60C, for example. As a result, the bottom opening hydraulic fluid passage 60 opens at a position corresponding to the bottom hydraulic fluid passage 47 of the body 32 (bottom 44 thereof) on one side on the outer surface of the spindle, and the other side is above the body 32 on the outer surface of the spindle 53. It is opened in the part which protruded. In this case, the other side of the bottom opening hydraulic fluid passage 60 opens at a position different from the other side of each cylinder opening hydraulic fluid passage 58.

  A portion of the spindle 53 facing the bottom surface 45 of the bottom portion 44 of the body 32 (lower end surface 53B) is provided with an annular recess 61 centered on the axis OO. The recessed portion 61 is located on the lower end surface 53B of the spindle 53 on the inner diameter side (axis OO side) with respect to the bottom opening hydraulic oil passage 60. The recessed portion 61 is concentric with the protruding portion 46 of the bottom portion 44, and the protruding portion 46 is inserted into the recessed portion 61 so as to be relatively rotatable. In this case, a small-diameter annular chamber 62 through which fuel flows is formed between the top of the protrusion 46 and the bottom of the recess 61 (gap). The small-diameter annular chamber 62 serves as a fuel chamber (fuel circulation chamber) for always communicating the body-side fuel supply passage 50 and the spindle-side fuel supply passage 63.

  The spindle 53 has a spindle-side fuel supply passage 63 as a second spindle-side insertion hole that penetrates between the upper end surface 53A of the spindle 53 and the bottom portion (bottom surface) of the recessed portion 61 upward and downward. It is provided as a hole. In this case, the spindle-side fuel supply passage 63 includes a vertical hole 63A extending in the axial direction of the spindle 53, and a portion of the outer surface (outer peripheral surface) of the spindle 53 protruding above (one side) the body 32 and the vertical hole 63A. It has a horizontal through hole (not shown) penetrating between them. The upper end opening of the vertical hole 63A is closed by, for example, a plug 63B. As a result, the spindle-side fuel supply passage 63 opens on one side to the position corresponding to the body-side fuel supply passage 50 at the bottom of the recessed portion 61 of the spindle 53 (the bottom surface of the recessed portion 61) and the other side on the outer surface of the spindle 53. An opening is made at a portion protruding upward from the body 32. In this case, the other side of the spindle side fuel supply passage 63 opens at a position different from the other side of each cylinder opening hydraulic fluid passage 58 and the other side of the bottom opening hydraulic fluid passage 60.

  The spindle 53 has a spindle-side fuel recovery passage 64 as a fifth spindle-side passage, and an upper end surface 53A of the spindle 53 and a side surface of the recessed portion 61 (specifically, an outer diameter surface of the recessed portion 61). It is provided as a through-hole penetrating between the two. In this case, the spindle-side fuel recovery passage 64 includes a lateral through hole 64A that penetrates between the outer diameter surface of the recessed portion 61 and the outer surface (outer peripheral surface) of the spindle 53, an upper end surface 53A of the spindle 53, and a lateral through hole 64A. And a vertical through hole 64B penetrating there between. The lateral through hole 64A is provided at the same height as the lateral through hole 51A of the paired body side fuel recovery passage 51.

  Further, the opening on the outer surface side of the spindle 53 in the lateral through hole 64A is closed by a plug 65, for example. As a result, the spindle-side fuel recovery passage 64 opens on one side to the position corresponding to the body-side fuel recovery passage 51 on the side surface (outer diameter surface) of the recessed portion 61 of the spindle 53, and the other side is the body 32 on the outer surface of the spindle 53. It opens in the part which protruded to the upper side. In this case, the other side of the spindle side fuel recovery passage 64 is located at a different position from the other side of each cylinder opening hydraulic fluid passage 58, the other side of the bottom opening hydraulic fluid passage 60, and the other side of the spindle side fuel supply passage 63. It is open.

  Further, the outer diameter surface of the recessed portion 61 is entirely at a position corresponding to the other side of the body side fuel recovery passage 51 (lateral through hole 51A) and one side of the spindle side fuel recovery passage 64 (lateral through hole 64A). A fuel recovery outer annular groove 66 is provided that is recessed radially outward over the circumference. On the other hand, on the inner diameter surface of the recessed portion 61, the fuel recovery recessed radially inward over the entire circumference at a position corresponding to the other side of the body side fuel recovery passage 51, that is, a position facing the fuel recovery outer annular groove 66. An inner annular groove 67 is provided.

  The outer annular groove 66 for fuel recovery always communicates the body side fuel recovery passage 51 and the spindle side fuel recovery passage 64 regardless of the relative rotation between the body 32 and the spindle 53. In other words, the fuel recovery outer annular groove 66 and the fuel recovery inner annular groove 67 are always in communication with the other side of the body side fuel recovery passage 51 regardless of the relative rotation of the body 32 and the spindle 53.

  Further, an outer annular groove 68 for collecting a mixed liquid that is recessed radially outward over the entire circumference is provided on the outer diameter surface of the recessed portion 61 at a position corresponding to the other side (lateral through hole 52A) of the mixed liquid collecting passage 52. It has been. On the other hand, on the inner diameter surface of the recessed portion 61, the mixed liquid that is recessed radially inward over the entire circumference at a position corresponding to the other side of the mixed liquid collection passage 52, that is, a position facing the mixed liquid collection outer annular groove 68. A recovery inner annular groove 69 is provided.

  In this case, the horizontal through-hole 52A provided in the protruding portion 46 of the bottom portion 44 of the body 32 constitutes a part of the mixed solution recovery passage 52, and the mixed solution recovery outer annular groove 68 and the mixed solution recovery inner ring. This is a communication path communicating with the groove 69. Accordingly, the mixed liquid recovery outer annular groove 68 and the mixed liquid recovery inner annular groove 69 are always in communication with one side of the mixed liquid recovery passage 52 regardless of the relative rotation of the body 32 and the spindle 53.

  Further, of the outer diameter surface of the recessed portion 61, it is located above the fuel recovery outer annular groove 66, between the fuel recovery outer annular groove 66 and the mixed liquid recovery outer annular groove 68, and as a mixed liquid recovery outer annular groove 68. On the lower side of 68, an outer sealing annular groove 70 is provided, which is recessed radially outward. In the outer seal annular groove 70, an outer upper seal member 71, an outer intermediate seal member 72, and an outer lower seal member 73 are fitted in order from the upper side.

  On the other hand, of the inner diameter surface of the recessed portion 61, it is located above the fuel recovery inner annular groove 67, between the fuel recovery inner annular groove 67 and the mixed liquid recovery inner annular groove 69, and between the mixed liquid recovery inner annular groove 69. On the lower side, there are provided inner sealing annular grooves 74 that are recessed radially inward. Inside the inner seal annular groove 74, an inner upper seal member 75, an inner intermediate seal member 76, and an inner lower seal member 77 are fitted in order from the upper side.

  In the outer upper seal member 71 and the inner upper seal member 75, the fuel flowing through the spindle side fuel supply passage 63 and the body side fuel supply passage 50 leaks below the outer upper seal member 71 and the inner upper seal member 75. This is what suppresses this. In the outer intermediate seal member 72 and the inner intermediate seal member 76, the fuel flowing through the spindle side fuel recovery passage 64 and the body side fuel recovery passage 51 leaks below the outer intermediate seal member 72 and the inner intermediate seal member 76. This is what suppresses this. The outer lower seal member 73 prevents hydraulic oil in the large-diameter annular chamber 57 from leaking upward from the outer lower seal member 73. The inner lower seal member 77 prevents the mixed liquid (mixed liquid in the mixed liquid recovery passage 52) in the mixed liquid recovery inner annular groove 69 from leaking below the inner lower seal member 77.

  Here, the sealing member is caused by the force applied between the upper swing body 10 and the lower traveling body 2, the pressure of the liquid flowing through each passage (pressure of hydraulic oil, fuel pressure), deterioration of the sealing member, and the like. Liquid (hydraulic oil, fuel) may leak from between 38, 71, 72, 73, 75, 76 and the mating surface with which the seal members 38, 71, 72, 73, 75, 76 are in sliding contact. In this case, for example, the fuel in the spindle-side fuel supply passage 63 and the body-side fuel supply passage 50 flows between the outer upper seal member 71 and the outer peripheral surface of the protrusion 46, and the inner periphery of the inner upper seal member 75 and the protrusion 46. When leaking downward from between the surfaces, the leaked fuel is recovered by the fuel recovery outer annular groove 66 and the fuel recovery inner annular groove 67.

  The fuel in the fuel recovery outer annular groove 66 and the fuel recovery inner annular groove 67 (that is, the fuel in the spindle-side fuel recovery passage 64 and the body-side fuel recovery passage 51) is the outer periphery of the outer intermediate seal member 72 and the protrusion 46. When the fuel leaks downward from between the inner surface and between the inner intermediate seal member 76 and the inner peripheral surface of the protrusion 46, the leaked fuel is mixed liquid collecting outer annular groove 68 and mixed liquid collecting inner annular groove. 69 (that is, the mixed liquid collection passage 52). On the other hand, when the hydraulic oil in the large-diameter annular chamber 57 leaks upward from between the outer lower seal member 73 and the outer peripheral surface of the protruding portion 46, the leaked hydraulic oil is mixed with the outer ring groove 68 for collecting the mixed liquid ( That is, it is collected in the mixed solution collection passage 52).

  The wheeled hydraulic excavator 1 and the center joint 31 according to the present embodiment have the above-described configuration, and the operation thereof will be described next.

  The wheeled hydraulic excavator 1 travels on a public road or the like toward a work site by driving a front wheel 4 and a rear wheel 5 provided on the lower traveling body 2. The wheel-type hydraulic excavator 1 performs excavation work of earth and sand using the work device 21 while turning the upper turning body 10 at the work site.

  On the other hand, in the center joint 31, the passages 35, 47, 50, 51 on the body 32 side and the passages 58, 60, 63, 64 on the spindle 53 side have annular grooves 36, 66, a large-diameter annular chamber 57, or The small diameter annular chamber 62 communicates with each other. For this reason, two types of liquids, that is, hydraulic oil and fuel, can be circulated between the upper swing body 10 and the lower traveling body 2 regardless of the swing operation of the upper swing body 10.

  That is, in the embodiment, the center joint 31 has a passage through which fuel flows, that is, a body side fuel supply passage 50, a spindle side fuel supply passage 63, a body side fuel recovery passage 51, and a spindle side fuel recovery passage 64. (Hereinafter referred to as fuel passages 50, 63, 51, 64) and passages through which hydraulic oil circulates, that is, the cylinder portion hydraulic oil passage 35, the cylinder opening hydraulic oil passage 58, the bottom hydraulic oil passage 47, and the bottom opening operation. An oil passage 60 (hereinafter referred to as hydraulic oil passages 35, 58, 47, 60) is provided. In the fuel passages 50, 63, 51, 64, a liquid (fuel) different from the liquid (hydraulic oil) flowing through the hydraulic oil passages 35, 58, 47, 60 can be circulated.

  On the other hand, the mixed liquid recovery passage 52 collects the liquid (hydraulic oil) leaked from the hydraulic oil passages 35, 58, 47, 60 and the liquid (fuel) leaked from the fuel passages 50, 63, 51, 64. It can be a liquid recovery passage. That is, the other side of the mixed liquid recovery passage 52 is open to the outer peripheral surface of the protrusion 46. For this reason, the outer peripheral surface of the protrusion 46 and the outside of the recessed portion 61 from the hydraulic oil passages 35, 58, 47, 60 (that is, the large-diameter annular chamber 57) through this opening (and the mixed liquid recovery outer annular groove 68). The liquid (hydraulic oil) leaked upward through the gap between the diametric surface and the outer peripheral surface of the protrusion 46 and the outside of the recess 61 from the fuel passages 50, 63, 51, 64 (that is, the outer annular groove 66 for fuel recovery). The liquid (fuel) leaked downward through the gap between the radial surfaces can be recovered.

  Further, the other side of the mixed liquid recovery passage 52 is also opened on the inner peripheral surface of the protrusion 46. Therefore, the inner peripheral surface of the protrusion 46 and the recessed portion 61 from the fuel passages 50, 63, 51, 64 (that is, the fuel recovery inner annular groove 67) through this opening (and the mixed liquid recovery inner annular groove 69). The liquid (fuel) leaked downward through the inner diameter surface of the gas can be recovered.

  In this case, the bottom hydraulic fluid passage 47, the body side fuel supply passage 50, the body side fuel recovery passage 51, and the mixed liquid recovery passage 52 are all provided in the bottom portion 44 of the body 32. For this reason, for example, as compared with a configuration in which a hydraulic fluid passage, a fuel passage, and a heterogeneous liquid recovery passage are arranged side by side in the axial direction (up and down), as in Patent Document 1, The axial dimension can be reduced. Thereby, the difficulty of processing can be reduced, the assembly work can be facilitated, and the vehicle body mountability (freedom of mounting) can be improved.

  That is, since the axial dimensions of the spindle 53 and the body 32 can be reduced, the concentricity and cylindricity of the spindle 53 and the body 32 can be easily ensured, and the difficulty of these processes can be reduced. Further, the weight of the spindle 53 and the body 32 can be reduced by the amount that the axial dimension can be reduced. For this reason, for example, when assembling the spindle 53 and the body 32, it is possible to reduce the burden (force necessary for the work) of the work of carrying and changing the posture. Thereby, it becomes easy to perform fine position adjustment etc., and assembly workability (assembly ease) can be improved.

  In addition, the distance between the portion where the seal member 38 in the spindle insertion hole 33 is attached and the open end can be shortened, and the visibility and workability (easy to attach) can be improved when the seal member 38 is attached. Furthermore, the space occupied by the center joint 31 when the center joint 31 is mounted on the vehicle body can be reduced, and the vehicle body mountability (freedom of mounting) can be improved. Further, when mounted on the vehicle body, it is possible to secure a space between the members around the center joint 31 and the center joint 31, and to improve the degree of freedom in handling piping (for example, hydraulic hose, fuel hose) and the like. You can also.

  In the embodiment, the other side of the mixed liquid recovery passage 52 is open to both the outer peripheral surface and the inner peripheral surface of the protrusion 46. Therefore, the outer peripheral surface and inner peripheral surface of the protrusion 46 from the fuel passages 50, 63, 51, 64 (that is, the outer annular groove 66 for fuel recovery and the inner annular groove 67 for fuel recovery) and the outer diameter surface of the recessed portion 61. Further, the liquid (fuel) leaking through between the inner diameter surface and the inner diameter surface can be recovered from both the outer peripheral surface side and the inner peripheral surface side of the protrusion 46. As a result, the mixed liquid recovery passage 52 can stably recover the liquid leaked from the fuel passages 50, 63, 51, 64.

  In the embodiment, the outer circumferential surface 68 and the inner circumferential groove for collecting the liquid mixture are disposed on the outer diameter surface and the inner diameter surface of the recessed portion 61 at positions corresponding to the other side of the mixed liquid collection passage 52. 69 is provided. Further, the projecting portion 46 is provided with a lateral through hole 52 </ b> A that communicates with the mixed liquid recovery outer annular groove 68 and the mixed liquid recovery inner annular groove 69 and serves as a part of the mixed liquid recovery passage 52. Therefore, the liquid (hydraulic oil, fuel) leaked toward the other side of the mixed liquid recovery passage 52 can be stably recovered through the mixed liquid recovery outer annular groove 68 and the mixed liquid recovery inner annular groove 69. Can do.

  In the embodiment, the outer diameter surface and the inner diameter surface of the recessed portion 61 are arranged at positions corresponding to the other side of the body side fuel recovery passage 51 and one side of the spindle side fuel recovery passage 64, respectively. A groove 66 and an inner annular groove 67 for fuel recovery are provided. Further, the projecting portion 46 is provided with a lateral through hole 51 </ b> A that communicates the fuel recovery outer annular groove 66 and the fuel recovery inner annular groove 67 and becomes a part of the body side fuel recovery passage 51. For this reason, the pressure in the fuel recovery outer annular groove 66 and the pressure in the fuel recovery inner annular groove 67 can be made substantially the same by the lateral through hole 51A. Thereby, the axial run-out of the protrusion part 46 and the recessed part 61, and the axial run-off of the body 32 and the spindle 53 can be suppressed, and the stability of these relative rotations can be improved.

  In the embodiment, fuel (or a mixed liquid containing fuel) flows through only the passages 50, 51, and 52 of the bottom portion 44 among the cylindrical portion 34 and the bottom portion 44 constituting the body 32. For this reason, only the bottom 44 of the body 32 may be made of a material that does not easily rust. That is, even if the material of the cylindrical portion 34 of the body 32 is cast iron, for example, it is possible to prevent rust from being mixed into the fuel. For this reason, compared with the structure which provides the channel | path which a fuel distribute | circulates to a cylinder part like the structure of patent document 1, the cost of the cylinder part 34 can be reduced.

  In the embodiment, the bottom hydraulic fluid passage 47 of the body 32 and the lower drain conduit 24B are connected, and the bottom opening hydraulic fluid passage 60 of the spindle 53 and the upper drain conduit 24A are connected. That is, the hydraulic fluid that flows through the bottom hydraulic fluid passage 47 and the bottom opening hydraulic fluid passage 60 is a drain oil having a low pressure. For this reason, the pressure of the hydraulic oil in the large-diameter annular chamber 57 can be reduced, and the hydraulic oil leaking upward from the large-diameter annular chamber 57 side beyond the outer lower seal member 73 can be reduced. Even when the hydraulic oil leaks, the leaked hydraulic oil can be stably recovered by the mixed liquid recovery outer annular groove 68.

  In the embodiment, the cylinder portion 34 of the body 32 is provided with four cylinder portion hydraulic oil passages 35 serving as first body side passages, and the cylinder 53 is provided with a cylinder opening hydraulic oil passage serving as the first spindle side passage. The case where four 58 are provided has been described as an example. However, the present invention is not limited to this, and the number of the first body side passage and the first spindle side passage is the number of hydraulic oil pipes connected between the upper swing body and the lower traveling body via the center joint. It can be increased or decreased depending on

  In the embodiment, the body 32 is provided with a bottom hydraulic fluid passage 47 serving as a fourth body side passage, and the spindle 53 is provided with a bottom opening hydraulic fluid passage 60 serving as a fourth spindle side passage. And explained. However, the present invention is not limited to this, and the fourth body side passage and the fourth spindle side passage may be omitted.

  In the embodiment, the body 32 is provided with a body-side fuel recovery passage 51 serving as a fifth body-side passage, and the spindle 53 is provided with a spindle-side fuel recovery passage 64 serving as a fifth spindle-side passage. Explained with an example. However, the present invention is not limited to this, and the fuel recovery passages (the fifth body side passage and the fifth spindle side passage) may be omitted as in the configuration of Patent Document 2, for example.

  In the embodiment, the case where the fifth body side passage and the fifth spindle side passage serving as the fuel recovery passages 51 and 64 are respectively provided as one example has been described. However, the present invention is not limited to this. For example, a plurality of fifth body side passages and fifth spindle side passages may be provided. In this case, the other side of each fifth body side passage and one side of each fifth spindle side passage can be opened side by side in the axial direction in the protruding portion and the recessed portion.

  In the embodiment, the case where the other side of the mixed liquid recovery passage 52 as the third body side passage is opened on both the outer peripheral surface and the inner peripheral surface of the protruding portion 46 has been described as an example. However, the present invention is not limited to this, and the other side of the third body side passage may be opened only on the outer peripheral surface of the protruding portion.

  In the embodiment, the case where the center hole 54 is provided in the spindle 53 (the spindle 53 is cylindrical) has been described as an example. However, the present invention is not limited to this. For example, the center hole of the spindle and the center hole at the bottom of the body may be omitted, and the spindle may be cylindrical (solid).

  In the embodiment, a seal member 38 that seals between the inner peripheral surface (spindle insertion hole 33) of the body 32 and the outer peripheral surface of the spindle 53 is provided on the body 32 side (an annular groove 37 for sealing is provided in the cylindrical portion 34). ) The case of the configuration is described as an example. However, the present invention is not limited to this. For example, the seal member may be provided on the spindle side (the sealing annular groove is provided on the spindle). That is, the seal member can be provided on the body side or the spindle side. Alternatively, one seal member may be provided on the body side and another seal member may be provided on the spindle side.

  In the embodiment, the case where the cylinder side annular groove 36 is provided on the inner peripheral surface (spindle insertion hole 33) of the body 32 has been described as an example. However, the present invention is not limited to this, and for example, a cylindrical annular groove that is recessed radially inward may be provided on the outer peripheral surface of the spindle. Moreover, you may provide in both. That is, the cylindrical annular groove can be provided on the inner peripheral surface (spindle insertion hole) of the cylindrical portion of the body and / or the outer peripheral surface of the spindle.

  In the embodiment, seal members 71, 72, which seal between the side surfaces (inner peripheral surface, outer peripheral surface) of the protruding portion 46 of the body 32 and the side surfaces (inner diameter surface, outer diameter surface) of the recessed portion 61 of the spindle 53. An example has been described in which 73, 75, 76, and 77 are provided on the side surface of the recessed portion 61 on the spindle 53 side (the sealing annular grooves 70 and 74 are provided on the recessed portion 61). However, the present invention is not limited to this. For example, the sealing member may be provided on the side surface of the protruding portion on the body side (the sealing annular groove is provided in the protruding portion). That is, the sealing member can be provided on the side surface (inner peripheral surface, outer peripheral surface) of the recessed portion or the side surface (inner diameter surface, outer diameter surface) of the protruding portion. Moreover, it is good also as a structure which provides one sealing member in the side surface (inner peripheral surface, outer peripheral surface) of a recessed part, and provides another sealing member in the side surface (inner diameter surface, outer diameter surface) of a protrusion part.

  In the embodiment, the case where the annular grooves 66, 67, 68, 69 are provided on the side surfaces (inner diameter surface, outer diameter surface) of the recessed portion 61 on the spindle 53 side has been described as an example. However, the present invention is not limited to this. For example, as in the modification shown in FIG. 8, a configuration in which the annular groove 81 is provided on the side surface (inner peripheral surface, outer peripheral surface) of the protruding portion 46 of the bottom portion 44 on the body 32 side. It is good. Moreover, you may provide in both. That is, the annular groove can be provided on the side surface (inner diameter surface, outer diameter surface) and / or the side surface (inner peripheral surface, outer peripheral surface) of the protrusion.

  In the embodiment, the case where the two types of liquid flowing through the center joint 31 are hydraulic oil and fuel has been described as an example. However, the present invention is not limited to this. For example, urea water for removing nitrogen oxides (NOx) in the exhaust gas may be used instead of the fuel. That is, the center joint can circulate various liquids that need to prevent one liquid and the other liquid from being mixed. Moreover, you may use as a center joint which distribute | circulates one type of liquid.

  In the embodiment, one of the two types of liquids is a fuel that easily contains moisture, and fuel passages 50, 63, 51, 64 through which the fuel flows are provided in the bottom 44 of the body 32 and the spindle 53, and The case where the bottom 44 of the body 32 and the spindle 53 are made of rust-resistant materials has been described as an example. However, the present invention is not limited to this, and various materials (materials) can be used for the body (bottom portion, cylindrical portion) and the spindle according to the flowing liquid.

  In the embodiment, the case where the cylindrical portion 34 and the bottom portion 44 of the body 32 are separate parts has been described as an example. However, the present invention is not limited to this. For example, the bottom portion and the cylindrical portion may be integrally formed, and the body may be an integral part.

  In the embodiment, the case where the body 32 is fixed to the lower traveling body 2 side and the spindle 53 is fixed to the upper swing body 10 side (when the lower side is the body 32 and the upper side is the spindle 53) will be described as an example. did. However, the present invention is not limited to this. For example, the spindle may be fixed to the lower traveling body side and the body may be fixed to the upper swing body side. That is, the upper and lower arrangements of the body and the spindle may be reversed (the upper side is the body and the lower side is the spindle). In this case, it can be set as the structure which provides the collection | recovery tank for collect | recovering liquid mixture in the upper revolving body side.

  Further, when the upper and lower arrangements of the body and the spindle are reversed, for example, the mixed liquid recovery passage on the body side may be omitted, and the mixed liquid recovery path may be provided on the spindle side. That is, instead of the third body side passage, one side opens to the outer diameter surface of the recessed portion of the spindle, and the other side opens to a position different from the first spindle side passage and the second spindle side passage on the outer surface of the spindle. The third spindle side passage may be provided. As described above, even when the third spindle side passage is provided instead of the third body side passage, the same operational effects as those provided by the third body side passage can be obtained.

  In the embodiment, the wheel-type hydraulic excavator 1 is described as an example of the construction machine to which the center joint 31 is attached. However, the present invention is not limited to this, and may be used, for example, as a center joint of a crawler hydraulic excavator. Further, the present invention can be widely used as a center joint to be attached to various construction machines provided with a revolving body such as a hydraulic crane as well as a hydraulic excavator. Further, although the center joint is attached between the lower traveling body and the upper swinging body that can travel, for example, instead of the lower traveling body, a center joint may be attached between the base body that does not travel and the swinging body.

  Furthermore, in the embodiment, the center joint used for the construction machine has been described as an example. However, the present invention is not limited to this. For example, the swivel joint used for various mechanical devices, that is, the liquid is circulated between the relatively rotating members. It can be widely applied as a swivel joint.

  According to the above embodiment, the axial dimension of the swivel joint can be reduced.

  That is, according to the embodiment, the second body side passage and the second spindle side passage are different from the liquid (hydraulic oil) flowing through the first body side passage and the first spindle side passage. Various types of liquid (fuel) can be distributed. The third body side passage includes liquid (hydraulic oil) leaked from the first body side passage and the first spindle side passage, and liquid leaked from the second body side passage and the second spindle side passage. It is possible to provide a different liquid recovery passage for recovering (fuel). That is, the other side of the third body side passage is open to the outer peripheral surface of the projecting portion, and through this opening, the outer peripheral surface of the projecting portion and the recessed portion from the first body side passage and the first spindle side passage. Leaked through between the outer diameter surface of the liquid and the liquid leaked through the second body side passage and the second spindle side passage through the outer peripheral surface of the protruding portion and the outer diameter surface of the recessed portion. (Fuel) can be recovered.

  In this case, one side of the second body side passage opens to the bottom of the body and the other side opens to the top of the protruding portion of the body, and one side of the second body side passage opens to the bottom of the body. The other side passes through a position different from the second body side passage and opens to the outer peripheral surface of the protrusion. For this reason, for example, as compared to a configuration in which a passage through which hydraulic oil flows, a passage through which fuel flows, and a different liquid recovery passage are arranged side by side in the axial direction of the swivel joint, as in Patent Document 1, for example, The axial dimension can be reduced. Thereby, the difficulty of processing can be reduced, the assembly work can be facilitated, and the vehicle body mountability (freedom of mounting) can be improved.

  According to the embodiment, the other side of the third body side passage opens to both the outer peripheral surface and the inner peripheral surface of the protrusion. Therefore, the liquid leaked from the first body side passage and the first spindle side passage (hydraulic oil) and the liquid (fuel) leaked from the second body side passage and the second spindle side passage protrude. It can collect | recover from both the outer peripheral surface side and inner peripheral surface side of a part. That is, the opening on the outer peripheral surface side of the projecting portion is the liquid (hydraulic oil) leaked from the first body side passage and the first spindle side passage through the outer peripheral surface of the projecting portion and the outer diameter surface of the recessed portion. The liquid (fuel) leaked from the second body side passage and the second spindle side passage through the outer peripheral surface of the protruding portion and the outer diameter surface of the recessed portion can be recovered. Further, the opening on the inner peripheral surface side of the protruding portion allows liquid (fuel) leaked from the second body side passage and the second spindle side passage through the inner peripheral surface of the protruding portion and the inner diameter surface of the recessed portion. It can be recovered. Thereby, the 3rd body side channel | path can collect | recover the leaked liquid stably from both the outer peripheral surface side and inner peripheral surface side of a protrusion part.

  According to the embodiment, on the outer diameter surface of the recessed portion, the outer annular groove that is recessed over the entire circumference is provided at a position corresponding to the other side of the third body side passage. For this reason, the liquid (hydraulic oil) leaked from the first body side passage and the first spindle side passage and the liquid (fuel) leaked from the second body side passage and the second spindle side passage are arranged in an outer ring shape. It is possible to stably collect the third body side passage through the groove.

  According to the embodiment, an inner annular groove that is recessed over the entire circumference is provided on the inner diameter surface of the recessed portion at a position corresponding to the other side of the third body side passage. For this reason, the liquid (fuel) leaked from the second body side passage and the second spindle side passage can be stably recovered into the third body side passage through the inner annular groove.

  According to the embodiment, in addition to the outer annular groove and the inner annular groove, the projecting portion is provided with a communication path that communicates the outer annular groove and the inner annular groove and becomes a part of the third body side passage. It has been. For this reason, the liquid (operating oil, fuel) leaked toward the other side of the third body side passage can be stably recovered through the outer annular groove and the inner annular groove. In addition, since the outer annular groove and the inner annular groove communicate with each other via the communication path of the protrusion, the pressure in the outer annular groove and the pressure in the inner annular groove can be made substantially the same. Thereby, the axial run-out between the projecting portion and the recessed portion, and hence the run-out between the body and the spindle can be suppressed, and the stability of these relative rotations can be improved.

1 Wheel excavator 31 Center joint (swivel joint)
32 Body 33 Spindle insertion hole 34 Tube portion 35 Tube portion hydraulic fluid passage (first body side passage)
44 Bottom 45 Bottom 46 Projection 48 Bottom (another surface)
50 Body side fuel supply passage (second body side passage)
52 Mixed liquid recovery passage (third body side passage)
52A Horizontal through hole (communication path)
53 Spindle 58 Cylinder opening hydraulic fluid passage (first spindle side passage)
61 Concave portion 63 Spindle side fuel supply passage (second spindle side passage)
68 Outer annular groove for liquid mixture recovery (outer annular groove)
69 Inner ring groove for collecting liquid mixture (inner ring groove)
OO axis of rotation axis

Claims (5)

A cylindrical and bottomed body provided with a spindle insertion hole and having a cylindrical portion and a bottom portion;
A columnar or cylindrical spindle inserted into the spindle insertion hole of the body so as to be relatively rotatable about the axis of the rotation axis;
A first body side passage having one side opened to the outer surface of the cylindrical portion of the body and the other side opened to the inner surface of the spindle insertion hole;
A first spindle having one side opened to a position corresponding to the first body side passage on the outer surface of the spindle, and the other side opened to the outer surface of the spindle at a position different from the position corresponding to the first body side passage. In a swivel joint comprising a side passage,
An annular projecting portion provided on a bottom surface of the bottom portion of the body facing the spindle and projecting from the bottom surface toward the spindle;
An annular recess provided in a portion of the spindle that faces the bottom surface of the bottom of the body, the protrusion of the bottom being inserted in a relatively rotatable manner;
A second body side passage having one side opened to the bottom of the body on a surface different from the bottom surface of the bottom of the body and the outer surface of the protrusion, and the other side opened to the top of the protrusion;
A second spindle side having one side opened to a position corresponding to the second body side passage at the bottom of the concave portion of the spindle and the other side opened to a position different from the first spindle side passage on the outer surface of the spindle A passage,
One side opens to the bottom of the body on a surface different from the bottom surface of the bottom of the body and the outer surface of the protrusion, and the other side passes through a position different from the second body side passage and the outer peripheral surface of the protrusion A swivel joint characterized by comprising a third body side passage that is open at the top.   2. The swivel joint according to claim 1, wherein the other side of the third body-side passage is open to both an outer peripheral surface and an inner peripheral surface of the protruding portion.   At least one of the outer peripheral surface of the projecting portion and the outer diameter surface of the recessed portion is provided with an outer annular groove that is recessed over the entire circumference at a position corresponding to the other side of the third body side passage. The swivel joint according to claim 1.   At least one of the inner peripheral surface of the projecting portion and the inner diameter surface of the recessed portion is provided with an inner annular groove that is recessed over the entire circumference at a position corresponding to the other side of the third body side passage. The swivel joint according to claim 2. At least one of the outer peripheral surface of the projecting portion and the outer diameter surface of the recessed portion is provided with an outer annular groove that is recessed over the entire circumference at a position corresponding to the other side of the third body side passage. And
At least one of the inner peripheral surface of the projecting portion and the inner diameter surface of the recessed portion is provided with an inner annular groove that is recessed over the entire circumference at a position corresponding to the other side of the third body side passage. And
3. The swivel joint according to claim 2, wherein the projecting portion is provided with a communication passage that communicates the outer annular groove and the inner annular groove and forms a part of the third body side passage.

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