JP5013490B2 - Swivel joint - Google Patents

Description

  The present invention relates to a swivel joint, and more particularly, to a swivel joint disposed at a turning portion that connects a lower traveling body and an upper turning body of a construction machine.

The hydraulic excavator includes a lower traveling body and an upper revolving body disposed on the lower traveling body so as to be able to swivel. Piping paths for hydraulic oil and the like in the lower traveling body and the upper swing body are connected by a swivel joint between the lower traveling body and the upper swing body, and the swivel joint allows the upper swing body to swing.
This type of swivel joint includes, for example, a cylindrical holder and a columnar spindle rotatably disposed in the holder, and a flow path is formed in each of the holder and the spindle. These flow paths are always connected regardless of the relative rotation of the holder and the spindle.

  Here, among hydraulic excavators, a wheel type hydraulic excavator is known in which a fuel tank is installed in the lower traveling body so that the fuel filler port is positioned at a lower position of the lower traveling body in consideration of the convenience of refueling. It has been. In this case, not only the hydraulic piping path connecting the hydraulic pump driven by the engine mounted on the upper swing body and the hydraulic travel motor provided on the lower travel body, but also the fuel on the engine and lower travel body side. The fuel system piping path connecting to the tank also needs to extend through the swivel joint.

Therefore, in the swivel joint used in such a hydraulic excavator, not only the hydraulic oil flow path for passing the hydraulic oil but also the fuel flow path for passing the fuel are provided.
The swivel joint provided with the fuel flow path is shown in FIGS. 3 and 4 of Patent Document 1, for example. The swivel joint of this Patent Document 1 is provided at the center of a spindle, and has a through-hole extending in the axial direction thereof, a fuel supply passage secured independently in the through-hole, a return passage for overflowed fuel, The return flow path includes a flow path in the swivel joint as a part of the return flow path.

Japanese Patent Laid-Open No. 02-283852

By the way, the high-pressure hydraulic fluid that flows inside the hydraulic fluid passage often has a relatively high temperature.
In the case of the swivel joint of Patent Document 1, since the fuel supply flow path is independently provided in the through hole of the spindle, the thermal influence of the supplied fuel flowing through the fuel supply flow path from the high temperature hydraulic oil is small. . However, since the return flow path is provided in the same spindle as the hydraulic oil flow path through which the high-temperature hydraulic oil flows, the return fuel flowing in the spindle is affected by the heat from the hydraulic oil. There is a risk that the fuel temperature will rise. When the fuel temperature rises in this way, the output of the engine decreases and the fuel consumption of the engine deteriorates.

Therefore, when using the swivel joint of Patent Document 1, in order to avoid the thermal influence from the high temperature hydraulic oil, a separate fuel cooler is installed in the fuel return piping path including the return flow path to suppress an increase in fuel temperature. Measures must be taken. For this reason, there exists a problem that the structure of a piping path becomes complicated and causes a high manufacturing cost.
Further, in the through hole in which the fuel supply channel is disposed, a certain amount of space is required between the two in order to avoid contact between the fuel supply channel and the rotating spindle. Moreover, such a space is also used for passing an electrical wiring or the like extending from a slip ring that makes electrical connection between the upper swing body side and the lower traveling body side, so the inner diameter of the through hole must be made larger. .

For this reason, in the case of the swivel joint of Patent Document 1, since the spindle itself becomes large, the outer diameter of the swivel joint as a whole also increases, and there is a problem that the mounting property to the construction machine is deteriorated.
The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a swivel that can suppress the thermal effect of fuel from high-temperature hydraulic oil and can be easily mounted. To provide a joint.

  In order to achieve the above object, a swivel joint of the present invention is provided in a construction machine including a lower traveling body and an upper revolving body that is pivotably provided on the lower traveling body, and the swivel of the upper revolving body is provided. Regardless of the swivel joint that connects the pipe on the lower traveling body side and the piping on the upper revolving body side, the swivel joint is arranged in a state of being fixed to one of the lower traveling body side or the upper revolving body side and opened to the outer surface thereof A holder having a plurality of holder-side ports, and is fixed to the other of the lower traveling body side or the upper revolving body side, and is rotatably fitted in the holder. A spindle having a plurality of spindle-side ports opened from an outer surface of the protrusion and a protrusion protruding from the holder; A plurality of connection paths that extend into the holder and the spindle and connect the holder-side port and the spindle-side port, which form a pair with each other, and individually have internal flow paths extending in the axial direction within the spindle; The internal flow path of the connection path includes a fuel flow path through which fuel flows and a plurality of hydraulic oil flow paths through which hydraulic oil flows. And a high-temperature region in which high-temperature hydraulic oil passages in which the temperature of the hydraulic oil is higher than the temperature of the fuel are gathered and arranged, and the fuel passage is arranged apart from the high-temperature region. (Claim 1).

According to the swivel joint of the first aspect, since the fuel flow path is provided away from the high temperature region, the fuel passing through the fuel flow path is not easily affected by the heat of the high temperature hydraulic oil. The rise can be suppressed.
Further, among the hydraulic fluid passages, the low-temperature hydraulic fluid passage in which the temperature of the hydraulic fluid is lower than that of the hydraulic fluid in the high-temperature hydraulic fluid passage is the high temperature region and the fuel flow when viewed in a cross section of the spindle. It is preferable to adopt a configuration arranged between the road (claim 2).

According to the swivel joint of the second aspect, since there is a low-temperature hydraulic fluid passage through which a relatively low-temperature hydraulic fluid flows between the fuel passage and the high-temperature hydraulic fluid passage, Heat transfer is reduced, and the fuel flowing in the fuel flow path is less likely to be affected by heat from the high temperature hydraulic oil.
In addition, it is preferable that the fuel flow path and the high-temperature hydraulic oil flow path have different lengths.

Specifically, the length of the fuel flow path is shorter than the length of the high temperature hydraulic oil path (Claim 4), or the length of the fuel flow path is equal to the high temperature hydraulic oil. It is set as the structure (Claim 5) longer than the flow path length.
According to the configuration of the fourth aspect, since the time for the fuel passing through the fuel flow path to pass through the spindle is shortened, the thermal influence from the high temperature hydraulic oil can be reduced.

According to the fifth aspect of the present invention, the length of the high-temperature hydraulic fluid passage in the spindle is relatively shortened, so that the heat transfer area of the spindle is reduced. For this reason, the thermal influence from high temperature hydraulic fluid can be made small.
Moreover, it is preferable that at least one of the fuel flow path and the high-temperature hydraulic oil flow path has a heat insulating layer between the spindle and the spindle.

According to the swivel joint of the sixth aspect, since either one or both of the fuel flow path and the high-temperature hydraulic oil flow path are provided with the heat insulating layer, the fuel flow path is affected by heat from the outside. As for the high-temperature hydraulic oil flow path, the release of heat to the outside can be suppressed. For this reason, an increase in the temperature of the fuel flowing in the fuel flow path can be suppressed.
The swivel joint further includes a slip ring that electrically connects the lower traveling body and the upper swing body, and the spindle has only an electrical wiring connected to the slip ring on its axis. It is preferable to further include a through-hole through which it passes (claim 7).

  According to the swivel joint of the seventh aspect, since only the electric wiring from the slip ring passes through the through hole of the spindle, it is not necessary to enlarge the swivel joint even if the through hole is provided. This contributes to the improvement of mountability.

  According to the swivel joint of the present invention according to any one of claims 1 to 7, even if the fuel flow path and the hydraulic oil flow path are provided in the same spindle body in the spindle, the thermal influence from the high temperature hydraulic oil. Can be suppressed as much as possible, and an increase in fuel temperature can be suppressed. For this reason, it is possible to prevent a decrease in engine output and a deterioration in fuel consumption. Further, it is not necessary to dispose the fuel supply pipe at the center of the swivel joint, and it is not necessary to increase the size of the central through hole, so that the entire swivel joint can be reduced in size. Therefore, the swivel joint of the present invention is excellent in mountability to a construction machine and contributes to a reduction in manufacturing cost of the construction machine.

It is a side view which shows the wheel type hydraulic excavator as a construction machine. It is a schematic block diagram which shows the connection aspect of the swivel joint which concerns on Example 1, and each piping. 1 is a cross-sectional view illustrating a vertical cross section of a swivel joint according to Embodiment 1. FIG. It is the IV-IV sectional view taken on the line of FIG. 6 is a cross-sectional view showing a vertical cross section of a swivel joint according to Embodiment 2. FIG. It is sectional drawing which expands and shows the part corresponding to the inside of the area | region b in FIG. 5 of the swivel joint which concerns on Example 3. FIG.

  Hereinafter, the form of the construction machine according to the present invention will be described with reference to the drawings.

Although it does not specifically limit as a construction machine to which this invention is applied, For example, the case where it applies to the wheel-type hydraulic shovel 2 shown in FIG. 1 is demonstrated to an example.
As shown in FIG. 1, the hydraulic excavator 2 includes a lower traveling body 4 and an upper revolving body 6 disposed on the lower traveling body 4 when viewed roughly.
The lower traveling body 4 includes wheels 8 disposed at the front and rear of the vehicle body, a hydraulic traveling motor (not shown) that drives the wheels 8, a steering mechanism (not shown) that changes the direction of the front wheels, A fuel tank 10 disposed in the middle between the left and right wheels 8 in the lower traveling body 4 is included.

  The upper swing body 6 includes an upper frame 14 that is turnably provided on the lower traveling body 4 via a swing bearing 12, and a cab 16 is provided on the front left side of the upper frame 14. A boom 18 extends from the right side of the cab 16, that is, from the front center portion of the upper frame 14. The boom 18 is raised and lowered by extending and contracting a pair of boom cylinders 20 disposed on both sides thereof. An arm 22 is rotatably connected to the tip of the boom 18, and a bucket 26 is attached to the tip of the arm 22 via a link mechanism 24. The arms 22 and the buckets 26 are also rotated by the expansion and contraction of the arm cylinders 28 and the bucket cylinders 30.

On the other hand, an engine room 32 is disposed behind the cab 16, and an engine 34 and a hydraulic pump (not shown) driven by the engine 34 are disposed in the engine room 32.
Inside the lower traveling body 4 and the upper swing body 6, hydraulic piping, fuel piping, electric circuit wiring, and the like constituting the hydraulic circuit are stretched, and these piping and the like are arranged in the central portion of the swing bearing 12. The lower traveling body 4 side and the upper revolving body 6 side are connected via the swivel joint 36 that has been made. In addition to the piping and wiring, the hydraulic excavator 2 is provided with functional parts (not shown) necessary for exhibiting the functions of the hydraulic excavator 2.

Next, the swivel joint 36 will be described in detail.
As shown in FIG. 2, the swivel joint 36 includes a cylindrical holder 38 disposed vertically and a columnar spindle 40 disposed in the holder 38.
The holder 38 has a flange 42 on the outer periphery of the upper end thereof, and is fixed to the vehicle body frame 44 of the lower traveling body 4 by bolts 46 with this flange 42. Thereby, the holder 38 is integrally coupled to the lower traveling body 4.

  On the other hand, the spindle 40 includes a spindle main body 48 that is inserted through the holder 38 in the most part. The spindle body 48 includes a protrusion 50 that protrudes upward from the flange 42 of the holder 38. A bracket 54 is attached to the upper end surface of the protruding portion 50 via a bolt 56, and the bracket 54 is supported by the support column 52. The support column 52 is erected on the upper frame 14 of the upper swing body 6. Thereby, the spindle 40 is integrally coupled to the upper swing body 6.

  More specifically, as is apparent from FIG. 3 showing the longitudinal section of the swivel joint 36, the holder 38 has a plurality of annular grooves 60 on its inner peripheral surface 58, and these annular grooves 60 are formed on the entire holder 38. It extends in the circumferential direction over the circumference, and is arranged at intervals in the axial direction of the holder 38. These annular grooves 60 have various longitudinal sectional areas. Each annular groove 60 communicates with a holder-side port 62. These holder-side ports 62 are formed in the holder 38, and extend from the annular groove 60 toward the radially outer side of the holder 38. Opened on the outer peripheral surface of the holder 38. An annular groove 64 having a relatively small cross-sectional area is provided between the annular grooves 60, and an O-ring 66 is provided in each of the annular grooves 64.

  Further, an O-ring 70 for preventing fluid leakage is disposed on the inner peripheral surface 58 of the upper end opening of the holder 38. A bushing 187 is disposed on the inner peripheral surface 58 below the O-ring 70. On the other hand, a disc-shaped lid 72 is attached to the lower end of the holder 38, and the lid 72 is fixed to the holder 38 via a bolt 78. The lid 72 has a recess 76 in the center of the inner surface, and the lower end of the spindle 40 is rotatably fitted in the recess 76. A through hole 74 is formed at the bottom of the recess 76.

  More specifically, as is clear from FIG. 3, the spindle 40 has a multistage cylindrical shape and has a central through hole 80. The central through hole 80 is disposed on the axis of the spindle 40. The spindle main body 48 of the spindle 40 includes an insertion portion 49 inserted into the holder 38 and a protrusion 50 protruding from the holder 38, and the insertion portion 49 is approximately 3/4 of the total length of the spindle 40. The protrusion 50 has a length of about 1/4 of the total length.

The outer peripheral surface 82 of the insertion portion 49 in the spindle 40 covers each of the annular grooves 60 of the holder 38 described above, and these annular grooves 60 are formed in the annular flow path 84, respectively. Since the above-described O-ring 66 exists between each annular flow path 84, fluid leakage from each annular flow path 84 is effectively prevented.
On the other hand, in the spindle main body 48 of the spindle 40, a plurality of narrow holes (hereinafter referred to as “axial passages 86”) are formed at portions avoiding the central through hole 80, and these axial passages 86 are formed in the spindle 40. It extends in the axial direction. Each axial flow path 86 reaches the insertion portion 49 from the upper surface of the protrusion 50 of the spindle 40 described above, and its upper end opening 88 is closed by a plug (not shown). Each axial channel 86 communicates with the spindle-side port 90 at its upper end and communicates with the communication hole 92 at its lower end. The spindle-side port 90 and the communication hole 92 extend in the radial direction in the spindle 40 and open to the outer peripheral surfaces of the protruding portion 50 and the insertion portion 49 of the spindle 40, respectively. The communication hole 92 of each axial flow path is arranged to communicate with the corresponding annular flow path 84.

  Further, the spindle 40, that is, the lower end portion of the spindle body 48 is formed as a boss 96 coaxial with the above-described central through hole 80, and this boss 96 is partially fitted into the above-described recess 76. A ring member 98 having a diameter larger than that of the spindle main body 48 is fitted into the base of the boss 96, and the ring member 98 is fixed to the spindle main body 48 via a bolt 100. The outer peripheral edge of the ring member 98 overlaps with a part of the lower end surface of the holder 38 so as to be slidable, and functions as a stopper for preventing the spindle 40 from coming off.

An O-ring 102 for preventing fluid leakage is disposed between the outer periphery of the tip of the boss 96 and the inner peripheral surface of the recess 76.
Here, a bushing 188 is disposed on the inner peripheral surface 58 of the lower end opening of the holder 38, and the spindle 40 can be rotated up and down by the upper bushing 187 and the lower bushing 188 described above. It is supported by.

  As described above, in the swivel joint 36, a flow path is formed from the spindle side port 90 through the spindle 40 and connected to the holder side port 62 via the annular flow path 84, and the spindle 40 rotates. Even in this case, the flow path is not closed, and communication between the spindle side port 90 and the holder side port 62, that is, communication between the upper revolving unit 6 side and the lower traveling unit 4 side can be always established.

Here, the configuration of the fuel piping and hydraulic piping on the lower traveling body 4 side and the upper revolving body 6 side connected through the swivel joint 36 will be described in more detail with reference to FIG.
First, regarding the fuel pipe, a fuel supply pipe 106 on the lower traveling body 4 side extending from the fuel tank 10 is connected to a fuel introduction port 108 which is one of the holder side ports 62. The fuel introduction port 108 communicates with a fuel lead-out port 110 that is one of the spindle-side ports 90 via a corresponding annular passage 84 and an axial passage 86. One end of the fuel supply pipe 112 on the upper swing body 6 side is connected to the fuel outlet port 110, and the other end of the fuel supply pipe 112 is connected to the engine 34.

  Further, a return pipe 114 on the upper swing body 6 side for overflow fuel extends from the engine 34, and this return pipe 114 is connected to an inlet-side return port 116 that is one of the spindle-side ports 90. It is connected. The entry-side return port 116 communicates with the exit-side return port 118 that is one of the holder-side ports 62 via the corresponding axial flow path 86 and the annular flow path 84. One end of a return pipe 120 on the lower traveling body 4 side is connected to the outlet return port 118, and the other end of the return pipe 120 is connected to the fuel tank 10. Thus, a fuel supply path and a return path are formed through the swivel joint 36 between the fuel tank 10 on the lower traveling body 4 side and the engine 34 on the upper swing body 6 side.

  Next, in the wheel-type hydraulic excavator 2, a steering mechanism, that is, a steering pump 122 that drives a steering cylinder (not shown), a drive pump 126 that drives a traveling motor 124, a boom cylinder 20 and a suspension cylinder (see FIG. Various hydraulic pumps such as a pilot pump 130 for supplying pilot pressure to a cylinder pump 128 and various hydraulic switching valves that drive a hydraulic pump are mounted on the upper swing body 6. It is driven by the engine 34 described above.

First, a steering hydraulic pipe 132 extends from the discharge port of the steering pump 122. A steering valve 134 is inserted in the middle of the steering hydraulic pipe 132, and the steering hydraulic pipe 132 is connected to an inlet side steering port 136 that is one of the spindle side ports 90 of the swivel joint 36.
The inlet side steering port 136 communicates with the outlet side steering port 138 which is one of the holder side ports 62 via the corresponding axial channel 86 and annular channel 84. One end of a steering hydraulic pipe 140 is connected to the output side steering port 138, and the other end of the steering hydraulic pipe 140 is connected to a steering cylinder.

  Here, the wheel-type hydraulic excavator 2 steers the front wheels by operating the handle in the cab 18. Specifically, the supply direction and supply amount of the hydraulic oil supplied from the steering pump 122 to the steering cylinder are controlled by the steering valve 134 that is switched according to the operation amount of the steering wheel. Can be changed. Also in such a steering hydraulic circuit, the piping on the upper swing body 6 side and the piping on the lower traveling body 4 side are connected via a swivel joint 36.

  Similarly, the hydraulic piping 144, 146, 148 on the upper swing body 6 extending from the drive pump 126, the cylinder pump 128, and the pilot pressure pump 130 are also connected to the spindle side port 90 of the swivel joint 36 in the same manner. 36 are connected to hydraulic piping 150, 152, and 154 on the lower traveling body 4 side through corresponding axial flow paths 86, annular flow paths 84, and holder-side ports 62. The hydraulic pipes 150, 152, and 154 are connected to the traveling motor 124, the suspension cylinder, and various hydraulic pressure switching valves, respectively. In this way, the hydraulic piping on the pumps 126, 128, and 130 side is also connected to the hydraulic piping on the lower traveling body 4 side via the swivel joint 36.

  Needless to say, the hydraulic pressure is supplied from the cylinder pump 128 to the boom cylinder 20 or the like belonging to the upper swing body side without passing through the swivel joint 36. In addition, the return of hydraulic oil from the steering cylinder, the traveling motor 124, the suspension cylinder, and the like is returned to a hydraulic oil tank (not shown) disposed in the upper swing body 6 through a swivel joint 36 by a pipe (not shown).

  As described above, the fuel pipes and hydraulic pipes on the lower traveling body 4 side and the upper revolving body 6 side are collected in the swivel joint 36, and as shown in FIG. It is arranged around the through hole 80. Here, since the hydraulic oil supplied to and discharged from the traveling motor 124 becomes particularly high in temperature, there is a possibility that the hydraulic oil flowing through the other shaft flow path 86 may be affected by heat through the spindle body 48 of the spindle 40. is there. In particular, if the temperature of the fuel rises due to this thermal influence, the engine output decreases and the fuel consumption deteriorates. Therefore, it is necessary to minimize the thermal influence on the fuel. Therefore, in the spindle 40, an axial flow path 86 through which hydraulic oil having a relatively high temperature flows and an axial flow path 86 through which hydraulic oil and fuel having a relatively low temperature flow are arranged apart from each other. .

  More specifically, as shown in FIG. 4, a motor supply flow path 160 and a motor return flow path 162 used for supplying and discharging hydraulic oil to and from the traveling motor 124, and a high temperature operation used for supplying and discharging high temperature hydraulic oil. The oil flow path 164 is disposed in a region a surrounded by a broken line, and is a low temperature used for supplying / discharging low temperature hydraulic oil, and a fuel supply flow path 166 and a fuel return flow path 168 used for supplying and discharging fuel. The hydraulic oil flow path 170 is disposed outside the region a.

  Specifically, in the region a, the motor supply channel 160 is positioned on the right side of the central through hole 80 as viewed in FIG. 4, and the motor return channel 162 is positioned on the upper side of the central through hole 80 as viewed in FIG. Yes. The high temperature hydraulic fluid passage 164 is positioned between the motor supply passage 160 and the motor return passage 162. Therefore, the region a in which the flow paths 160, 162, and 164 on the high temperature hydraulic oil side are collected becomes a high temperature region.

On the other hand, the fuel supply channel 166 is positioned so as to be spaced apart from the motor supply channel 160 across the central through hole 80, and the fuel return channel 168 is located above the fuel supply channel 166 as viewed in FIG. It is positioned.
Note that the low-temperature hydraulic fluid passage 170 through which low-temperature hydraulic fluid such as pilot pressure oil flows is positioned below the central through hole 80 as viewed in FIG.

  Further, as is clear from FIG. 3, the length of the fuel supply channel 166 is set shorter than the length of the motor supply channel 160. As a result, the time required for the fuel to pass through the spindle 40 is shortened, and the thermal influence on the fuel from the high temperature hydraulic oil can be reduced. Similarly, the length of the fuel return channel 168 is set to be shorter than the length of the motor supply channel 160.

  Further, as shown in FIG. 4, the steering passages 172 and 174 used for supplying and discharging the hydraulic oil to and from the steering cylinder are provided between the fuel supply passage 166 and the motor return passage 162 and between the fuel return passage 168 and the motor. They are respectively positioned between the return channel 162 and the return channel 162. Since the hydraulic oil supplied to and discharged from the steering cylinder is at a lower temperature than the hydraulic oil supplied to and discharged from the traveling motor, the fuel supply channel 166, the fuel return channel 168, the motor supply channel 160, and the motor If the steering flow paths 172 and 174 are positioned between the return flow path 162 and the return flow path 162, it contributes to the suppression of the fuel temperature rise.

  That is, since the steering flow paths 172 and 174 are used for circulation of relatively low temperature hydraulic oil, heat transfer from the high temperature region a to the fuel supply flow path 166 and the fuel return flow path 168 is reduced. In addition, since the lengths of the fuel supply channel 166 and the fuel return channel 168 are relatively short, the time during which the fuel is exposed to heat can also be shortened. Therefore, an increase in fuel temperature can be effectively suppressed.

As a result, according to the hydraulic excavator 2 provided with the above-described swivel joint 36, an increase in fuel temperature is suppressed, so that a decrease in engine output is prevented and a deterioration in fuel consumption is also suppressed.
Further, according to the swivel joint 36 of the present embodiment, it is not necessary to arrange a pipe in place of the fuel supply flow path 166 and the fuel return flow path 168 in the central through hole 80 of the spindle 40. Only the electric wiring 196 to the slip ring 194 that electrically connects the electric circuit 190 on the upper swing body 6 side and the electric circuit 192 on the lower traveling body 4 side is inserted (see FIG. 2). In other words, in the swivel joint 36, the central through hole 80 of the spindle need only be a space that allows only electrical wiring to pass therethrough. Can be obtained. Therefore, the swivel joint 36 is excellent in mountability to a construction machine.

  Further, according to the swivel joint 36, the increase in the fuel temperature can be effectively suppressed, so that it is not necessary to separately provide a fuel cooler, which contributes to a reduction in manufacturing cost of the entire hydraulic excavator.

Next, the swivel joint 37 of Example 2 applied to the hydraulic excavator 2 will be described with reference to FIG. In the description of the second embodiment, members and parts that exhibit the same functions as those of the first embodiment described above are denoted by the same reference numerals, the description thereof is omitted, and only the differences are described. To do.
In the case of the swivel joint 37, the lengths of the motor supply channel 182 and the motor return channel (not shown) are set shorter than the fuel supply channel 180 and the fuel lean channel (not shown).

  As a result, the distance of the flow path through which the high temperature hydraulic oil flows in the spindle 40 becomes relatively short, heat transfer from the high temperature region a can be reduced, and the thermal influence on the fuel can be reduced.

Next, the swivel joint of Example 3 applied to the hydraulic excavator 2 will be described with reference to FIG. In the description of the third embodiment, the same reference numerals are assigned to members and parts that exhibit the same functions as those of the first and second embodiments described above, and the description thereof is omitted and is different. Only the point will be described.
FIG. 6 shows an enlarged view of a portion corresponding to a region b surrounded by a broken line in FIG. As apparent from FIG. 6, a double-rolled steel pipe 186 is inserted into an axial flow path 86 used for fuel supply, and the double-wrapped steel pipe 186 is formed as a fuel supply flow path 184. Yes. A similar double-rolled steel pipe is also inserted in the fuel return channel.

The double-rolled steel pipe 186 interposed between the spindle body 48 of the spindle 40 and the fuel forms a heat insulating layer, suppresses heat transfer to the fuel, and can reduce the heat influence from the high temperature hydraulic oil to the fuel. .
In addition, this invention is not limited to the aspect of above-mentioned Examples 1-3, A various deformation | transformation is possible.

In the third embodiment, the double-rolled steel pipe is disposed toward the flow path through which the fuel flows. However, the present invention is not limited to this mode, and the double-winding is provided in the flow path through which the high-temperature hydraulic oil flows. It is good also as an aspect which arrange | positions a steel pipe. According to this aspect, heat transfer from the high-temperature hydraulic oil passage to the spindle body 48 can be reduced.
In addition, the pipe material disposed in the flow path of the fuel or the high-temperature hydraulic oil is not limited to the double-rolled steel pipe, and may be a pipe material made of a material having excellent heat insulation, Tube material, ceramic tube material, or the like may be used.

  Further, in the above embodiment, the aspect in which the annular groove is provided on the holder side has been described. However, the present invention is not limited to this aspect, and an aspect in which the annular groove is provided on the outer periphery of the spindle may be employed. Further, it is possible to adopt an aspect in which an annular groove corresponding to both the holder and the spindle is provided. In other words, any mode is acceptable as long as an annular flow path can be formed between the inner peripheral surface of the holder and the outer peripheral surface of the spindle by the inner wall of the holder and the outer wall of the spindle.

Further, in the above-described embodiment, the aspect in which the spindle is fixed to the upper swing body side and the holder is fixed to the lower traveling body side has been described, but the present invention is not limited to this aspect, and these are reversed. The holder may be fixed to the upper swing body side and the spindle may be fixed to the lower traveling body side.
In the above embodiment, the wheel-type hydraulic excavator has been described. However, the present invention is not limited to this mode, and may be adopted in other construction machines having an upper-part turning body such as a crawler-type hydraulic excavator. You can also.

2 Hydraulic excavator (construction machine)
4 Lower traveling body 6 Upper revolving body 10 Fuel tank 14 Upper frame 16 Driver's cab 34 Engine 36 Swivel joint 38 Holder 40 Spindle 44 Car body frame 48 Spindle body 49 Insertion part 50 Protrusion part 58 Inner peripheral surface 60, 64 Toroidal groove 62 Holder Side port 66 O-ring 80 Central through hole 86 Axis flow path 90 Spindle side port 106, 112 Fuel supply pipe 108 Fuel introduction port 110 Fuel outlet port 114, 120 Return pipe 116 Inlet return port 118 Outlet return port 122 Steering pump 124 Traveling motor 126 Drive pump 128 Cylinder pump 130 Pilot pressure pump 132 Steering hydraulic piping 134 Steering valve 136 Incoming steering port 138 Outgoing steering port 140 Steering Pressure pipe 160 motor supply passage 162 motor return line 164 high temperature working fluid flow path 166 the fuel supply passage 168 fuel return passage 170 low-temperature operating fluid channel 172, 174 the steering channel 186 double-wrap steel tubes 187, 188 bushing

Claims (7)

Provided on a construction machine comprising a lower traveling body and an upper revolving body provided on the lower traveling body so as to be able to swivel, the piping on the lower traveling body side and the upper revolving body side regardless of the turning of the upper revolving body In the swivel joint that connects
A holder having a plurality of holder-side ports that are arranged in a state fixed to one of the lower traveling body side or the upper revolving body side and open to the outer surface thereof;
A spindle that is rotatably fitted in the holder in a state of being fixed to the other of the lower traveling body side or the upper revolving body side, and that rotates in the holder as the upper revolving body rotates. A spindle having a protrusion protruding from the holder and a plurality of spindle-side ports opened to the outer surface of the protrusion;
A plurality of connection paths that extend into the holder and the spindle and connect the holder-side port and the spindle-side port, which form a pair with each other, and individually have internal flow paths extending in the axial direction within the spindle; With
The internal flow path of the connection path is
A fuel flow path through which fuel flows;
A plurality of hydraulic oil passages through which hydraulic oil flows,
The spindle has a high temperature region in which the high temperature hydraulic oil passages in which the temperature of the hydraulic oil is higher than the temperature of the fuel are collectively arranged in the hydraulic oil passage when viewed in cross section, A swivel joint, wherein a fuel flow path is disposed apart from the high temperature region.   Among the hydraulic fluid passages, a low-temperature hydraulic fluid passage in which the temperature of the hydraulic fluid is lower than that of the hydraulic fluid in the high-temperature hydraulic fluid passage is the high temperature region and the fuel passage when viewed in a cross section of the spindle. The swivel joint according to claim 1, wherein the swivel joint is disposed between the two.   The swivel joint according to claim 1 or 2, wherein the fuel flow path and the high-temperature hydraulic oil flow path have different lengths.   The swivel joint according to claim 3, wherein a length of the fuel flow path is shorter than a length of the high temperature hydraulic oil flow path.   The swivel joint according to claim 3, wherein a length of the fuel flow path is longer than a length of the high temperature hydraulic oil flow path.   The swivel joint according to any one of claims 1 to 5, wherein at least one of the fuel flow path and the high-temperature hydraulic oil flow path includes a heat insulating layer between the spindle and the spindle. The swivel joint is
A slip ring for electrically connecting the lower traveling body and the upper swing body;
The swivel joint according to any one of claims 1 to 6, wherein the spindle further includes a through hole through which only an electric wiring connected to the slip ring passes on an axis thereof.

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