Working machinery

Abstract

To provide a work machine that can suppress weight increase while improving visibility. [Solution] The work machine 1 comprises a lower traveling body 2, an upper rotating body 3 that is rotatably supported on the upper part of the lower traveling body 2, and a cable reel 40 that is positioned substantially concentrically with the pivot center of the upper rotating body 3 and capable of winding and unwinding a power transmission cable 37 for supplying power to the power receiving unit by rotation.

Description

Technical Field

[0001] The present invention relates to a work machine including a cable reel capable of winding up and paying out a power transmission cable by rotation.

Background Art

[0002] Conventionally, in a power shovel that operates while connecting a power transmission cable, a cable reel that automatically winds up and pays out the power transmission cable around a vertical axis is arranged on a track frame of a lower traveling body so as not to impair vehicle running performance, operability, workability, etc. In these cases, the cable reel is located between the left and right track frames behind the turning axis of the upper slewing body (see, for example, Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the case of the above configuration, since the center of gravity position of the cable reel is far from the track frame to be attached, it is necessary to add a beam or the like to increase the strength of the holding structure of the cable reel, resulting in an increase in weight. Also, in a state where the upper slewing body is turned to face the rear, since the cable reel is arranged so as to block the space between the left and right crawlers, the visibility of the lower rear part is poor. Further, since the cable reel protrudes into the working range of the front work machine, there is also a concern that it may come into contact with the front work machine and be damaged.

[0005] Furthermore, in order to wind and unwind the power transmission cable in accordance with the vehicle's movement, the cable reel itself rotates, while the base of the power transmission cable wound onto the cable reel needs to be connected to the vehicle body. Therefore, a slip ring is required to allow rotation between the cable reel and the vehicle body to prevent the power transmission cable from twisting. In addition, since the motor driven by the supplied power is located on the upper rotating body, the power transmission cable needs to be electrically connected from the lower running body to the upper rotating body. Therefore, a slip ring is also required to allow rotation between the lower running body and the upper rotating body to prevent the power transmission cable from twisting even when the upper rotating body rotates.

[0006] This invention has been made in view of these points, and aims to provide a work machine that can suppress weight increase and improve visibility. [Means for solving the problem]

[0007] The work machine of the present invention comprises a lower traveling body, an upper rotating body rotatably supported on the upper part of the lower traveling body, and a cable reel positioned substantially concentrically with the pivot center of the upper rotating body, capable of winding and unwinding a power transmission cable for supplying power to a power receiving unit by rotation. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress weight increase and improve visibility. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic side view showing a part of the first embodiment of the work machine according to the present invention. [Figure 2] This is a schematic front view showing a part of the same work machine. [Figure 3] This is a schematic plan view showing a part of the same work machine. [Figure 4] This is a schematic side view showing a part of a second embodiment of the work machine according to the present invention. [Figure 5] This is a schematic side view showing a part of a third embodiment of the work machine according to the present invention. [Modes for carrying out the invention]

[0010] The present invention will be described in detail below based on the first embodiment shown in Figures 1 to 3, the second embodiment shown in Figure 4, and the third embodiment shown in Figure 5.

[0011] First, the embodiments shown in Figures 1 to 3 will be described.

[0012] In Figures 1 to 3, 1 represents a working machine. The working machine 1 is a rotating type working machine having a lower traveling body 2 and an upper rotating body 3, and in the illustrated example, a hydraulic excavator is given as an example. The working machine 1 in this embodiment is a wired electric hydraulic excavator that operates by receiving power via a wire from an externally located power supply unit (power supply equipment) PS.

[0013] The lower running body 2 is exemplified by a tracked running gear. The lower running body 2 comprises a frame 5. The frame 5 integrally includes a pair of left and right track frames 6 and a central main frame 7 to which these track frames 6 are connected. The track frames 6 are formed longitudinally along the direction of travel of the lower running body 2. One or more carrier rollers and multiple track rollers are rotatably supported on the upper and lower parts of the track frames 6. A sprocket, which is a drive wheel driven by a running motor 11, is mounted on one end of the track frame 6 in the longitudinal direction, and an idler, which is a driven wheel, is rotatably supported on the other end of the track frame 6 in the longitudinal direction. The running motor 11 is, for example, a fluid pressure motor (hydraulic motor). An endless track 14 is wrapped around the carrier rollers, track rollers, sprocket, and idler.

[0014] Furthermore, the main frame 7 is provided with a bearing section 16 that pivotally supports the upper rotating body 3. In other words, the bearing section 16 forms the pivot center of the upper rotating body 3. The bearing section 16 extends along the vertical direction, that is, in the vertical direction.

[0015] The upper rotating body 3 has a rotating frame 20. The rotating frame 20 is equipped with a cab 21 that partitions the driver's cabin where the operator sits, a front work implement 22 which is an operable work device operated by the operator, a tank 23 such as a hydraulic oil tank for storing hydraulic fluid, a counterweight, and the like.

[0016] Furthermore, a slewing bearing 25 is positioned at the bottom of the slewing frame 20. The slewing bearing 25 rotatably supports the outer circumference of the bearing portion 16. One or more slewing motors are meshed with the slewing bearing 25, and the upper slewing body 3 rotates relative to the lower traveling body 2 as the slewing motors rotate. The slewing motors are, for example, hydraulic motors, but electric motors may also be used.

[0017] A swivel joint (rotary joint) 28 is coaxially arranged in the bearing section 16. The swivel joint 28 has a double structure comprising a rotor and an outer case, and the rotor is rotatable relative to the outer case. One end of the rotor and outer case of the swivel joint 28 is attached to the main frame 7 of the lower traveling body 2, and the other end of the rotor and outer case is attached to the slewing frame 20 of the upper slewing body 3. A hydraulic fluid passage 30 on the lower traveling body 2 side and a hydraulic fluid passage 31 on the upper slewing body 3 side are liquid-tightly connected via a connecting passage formed between the rotor and the outer case.

[0018] In this embodiment, since the traveling motor 11 is a hydraulic motor, the hydraulic oil passage 30 is connected to the traveling motor 11. Further, the hydraulic oil passage 31 is connected to the swivel joint 28 and a hydraulic pump 34 disposed on the upper revolving body 3. The hydraulic pump 34 discharges and supplies the hydraulic oil stored in the hydraulic oil tank to hydraulic motors such as the traveling motor 11 and the slewing motor, and / or hydraulic actuators such as hydraulic cylinders for operating the front working machine 22 or the like via a control valve.

[0019] In this embodiment, the hydraulic pump 34 is driven by an electric motor 35. The electric motor 35 is a power receiving unit that operates by receiving power supply from the power supply unit PS.

[0020] The power from the power supply unit PS is supplied via a power transmission cable 37. The power transmission cable 37 is configured such that, for example, a thin power transmission cable for low voltage and a thick power transmission cable for high voltage are integrally held inside a flexible tube. The working machine 1 of this embodiment basically operates while the power transmission cable 37 is connected. Therefore, the working machine 1 includes a cable reel 40 that can adjust its length according to the positional relationship with the power supply unit PS and the moving speed by winding up and paying out the power transmission cable 37 by rotation.

[0021] The cable reel 40 used is a horizontally rotatable (vertical type) one having a rotation axis along the vertical direction. The cable reel 40 is disposed substantially concentrically with the rotation center of the upper revolving body 3. That is, the cable reel 40 is coaxial with the bearing portion 16, the slewing bearing 25, the swivel joint 28, and the like.

[0022] In this embodiment, the cable reel 40 is positioned, for example, between the lower traveling body 2 and the upper slewing body 3. The cable reel 40 is located between the frame 5 and the slewing frame 20. In the illustrated example, the cable reel 40 is attached to the lower part of the slewing frame 20 of the upper slewing body 3 and is located above the lower traveling body 2. The cable reel 40 has larger inner and outer diameter dimensions than the slewing bearing 25 and is positioned approximately concentrically with the slewing bearing 25 so as to surround the outer circumference of the slewing bearing 25. Therefore, the cable reel 40 is set to have a large diameter without interfering with its surroundings. At the same time, the cable reel 40 has an outer diameter that fits within the width of the upper slewing body 3 (slewing frame 20) and does not protrude from the upper slewing body 3 when viewed from above.

[0023] In the illustrated example, the cable reel 40 is mounted so as to hang from the lower part of the upper slewing body 3 (slewing frame 20) via a bearing 41. In other words, in this embodiment, the bearing 41 is located on the upper slewing body 3 (slewing frame 20). The cable reel 40 has an annular gear section 42 integrally and is configured to be rotated by a motor 43 that meshes with this gear section 42 via a reduction gear. In this embodiment, the gear section 42 is shaped so as not to protrude from the outer shape of the cable reel 40, is integral to the upper part of the cable reel 40, and meshes with the motor 43 mounted on the lower part of the upper slewing body 3 (slewing frame 20). Therefore, the cable reel 40 can rotate independently of the upper slewing body 3. Alternatively, the gear section 42 may be located on the upper slewing body 3 side and the motor 43 on the cable reel 40 side.

[0024] The bearing 41 has a structure that is the opposite of, for example, the swivel bearing 25, in terms of its orientation.

[0025] The motor 43 is positioned inside the outer dimensions of the cable reel 40. Depending on its position, the motor 43 can be either an electric motor or a hydraulic motor. The motor 43 is driven via the control unit 45, which automatically rotates the cable reel 40 to unwind or rewind the power transmission cable 37 relative to the cable reel 40. The control unit 45 uses an inverter or the like to output a control signal to control the drive of the motor 43.

[0026] In this embodiment, since the cable reel 40 is located between the lower traveling body 2 and the upper rotating body 3, there is no need to fix the winding direction of the power transmission cable 37. The power transmission cable 37 can be led out in any direction from the space between the lower traveling body 2 and the upper rotating body 3, and the rotation angle of the cable reel 40 is controlled so that the winding direction faces the power supply unit PS, depending on the posture and position of the work machine 1. Regarding the winding direction of the cable reel 40, if a reel guide is provided on the cable reel 40, the direction of the reel guide becomes the winding direction. For example, a track cover may be provided to cover the track 14 so that the power transmission cable 37 does not come into contact with the track 14, or a cable guide may be provided to hold the power transmission cable 37 floating above the track 14 to the outside of the track 14.

[0027] The end of the power transmission cable 37 wound around the cable reel 40 is electrically and mechanically connected to a slip ring 47 which is positioned approximately concentrically with the bearing 41 and slewing bearing 25 that suspend the cable reel 40. This slip ring 47 is electrically connected by wiring 48 to a power receiving unit such as an electric motor 35 located on the upper slewing body 3. In other words, the power transmission cable 37 is electrically connected to the inside of the upper slewing body 3 via the slip ring 47 and supplies power to the upper slewing body 3. That is, in this embodiment, the slip ring 47 is located on the upper slewing body 3 (slewing frame 20).

[0028] The slip ring 47 is configured such that the brushes slide against an annular electrical circuit. In this embodiment, the slip ring 47 is positioned such that the electrical circuit surrounds the outside of the swivel bearing 25 and is located inside the bearing 41 and the cable reel 40. The power receiving unit is electrically connected to this electrical circuit, and the power transmission cable 37 is electrically connected to the brushes. In this embodiment, the power transmission cable 37 is directly connected to the upper swivel body 3 by bypassing the lower traveling body 2, so that the power transmission cable 37 can be electrically connected to the inside of the upper swivel body 3 with only one slip ring 47.

[0029] The control unit 45 monitors the posture and position of the work machine 1 via sensors and outputs control signals accordingly. When the work machine 1 is moving away from the power supply unit PS, the motor 43 rotates the cable reel 40 to feed out the power transmission cable 37 in accordance with the moving speed. When the work machine 1 is approaching the power supply unit PS, the motor 43 rotates the cable reel 40 to rewind the power transmission cable 37. Thus, the connection between the work machine 1 and the power supply unit PS via the power transmission cable 37 is maintained, and the work machine 1 can operate while the power receiving unit is operated by the power supplied from the power supply unit PS via the power transmission cable 37. In addition, the control unit 45 controls the rotation angle of the cable reel 40 so that the winding direction is oriented towards the power supply unit PS by controlling the operation of the motor 43 according to the posture and position of the work machine 1.

[0030] As described above, by positioning the cable reel 40 approximately concentrically with the pivot center of the upper slewing body 3, in this embodiment, the cable reel 40 can be suspended from the upper slewing body 3 via the bearing 41. Therefore, it is not necessary to add a robust beam structure to hold the cable reel 40, and the increase in weight can be suppressed. Furthermore, because the cable reel 40 is positioned at the pivot center of the upper slewing body 3, the cable reel 40 can be contained within the width of the upper slewing body 3 and will not protrude from the upper slewing body 3 when viewed from above. As a result, even when the upper slewing body 3 is slewing, the cable reel 40 does not obstruct the operator's view, improving visibility, and also preventing the front work implement 22 from coming into contact with the cable reel 40.

[0031] Furthermore, in conventional examples, such as arranging a cable reel between the rear sections of the track frame, the outer diameter of the cable reel is limited to a size that avoids interference with the swivel bearing and tracks. In contrast, the cable reel 40 of this embodiment is located around the swivel bearing 25 and above the lower running body 2, allowing for a larger outer diameter without interfering with the surroundings, thus ensuring the required cable length even with fewer turns. Additionally, by increasing the outer diameter of the cable reel 40, it becomes possible to reduce the vertical thickness of the cable reel 40 to the thickness of a single power transmission cable 37 without overlapping the power transmission cables 37. In other words, with horizontal cable reels, it is difficult to keep the height below the minimum bending diameter of the power transmission cable, and the height becomes particularly large because the minimum bending radius of high-voltage power transmission cables is very large. In contrast, in this embodiment, the height of the cable reel 40 can be significantly reduced, resulting in a simpler, lighter design that prevents entanglement of the power transmission cable 37.

[0032] Furthermore, if the winding direction of the power transmission cable in the cable reel is fixed, when the cable reel is rotated or changed direction so that it faces a direction different from the direction of the power supply unit, the power transmission cable will bend at the end of the cable reel or reel guide. If force is applied in this bent state and the bending radius falls below the minimum bending radius of the power transmission cable, there is a risk that the power transmission cable will break. In contrast, in this embodiment, since there is no need to fix the winding direction of the power transmission cable 37 in the cable reel 40, even if the upper rotating body 3 rotates or the lower traveling body 2 changes direction, the winding direction of the power transmission cable 37 can always be directed towards the power supply unit PS, thus preventing damage caused by bending of the power transmission cable 37.

[0033] Since only one expensive slip ring 47 is needed, the work machine 1 can be constructed at a low cost.

[0034] Furthermore, by positioning the slip ring 47 on the upper rotating body 3, which has ample space, the size of the slip ring 47 can be significantly reduced.

[0035] Next, a second embodiment shown in Figure 4 will be described. Note that parts similar to those in the embodiments shown in Figures 1 to 3 will be denoted by the same reference numerals, and their description will be simplified.

[0036] In this embodiment, the cable reel 40 is positioned approximately concentrically with the pivot center of the upper swivel body 3, between the lower travel body 2 and the upper swivel body 3, and is located on the upper part of the lower travel body 2 (main frame 7) via the bearing 41. In other words, the cable reel 40 and the bearing 41 are located on the lower travel body 2 (main frame 7).

[0037] Furthermore, a gear section 42 is formed at the bottom of the cable reel 40, and a motor 43 that meshes with the gear section 42 is located on the lower traveling body 2 (main frame 7). Preferably, the motor 43 is located on the rear side of the lower traveling body 2 (main frame 7). By driving the motor 43, the cable reel 40 can rotate independently of the lower traveling body 2.

[0038] The slip ring 47 is positioned approximately concentrically with the bearing 41 and the slewing bearing 25. In this embodiment, the slip ring 47 is positioned inside the bearing 41 on the lower traveling body 2 (main frame 7).

[0039] The swivel joint 28 has a wiring insertion hole 50 formed along the central axis of the rotor, and wiring 51, which is electrically and mechanically connected to the slip ring 47, is inserted through the wiring insertion hole 50. Furthermore, a slip ring 52 is arranged coaxially with the swivel joint 28 at the top of the swivel joint 28, and the wiring 51 inserted through the wiring insertion hole 50 is electrically and mechanically connected to the slip ring 52. The slip ring 52 is then electrically connected to a power receiving unit such as an electric motor 35 in the upper rotating body 3 via wiring 53. Thus, the power transmission cable 37 is electrically connected to the power receiving unit via the slip rings 47 and 52, and power is supplied to the power receiving unit from the power supply unit PS.

[0040] As described above, by having a configuration similar to the first embodiment, such as positioning the cable reel 40 substantially concentrically with the pivot center of the upper slewing body 3, this embodiment allows the cable reel 40 to be mounted on the existing main frame 7 of the lower traveling body 2 via the bearing 41. Therefore, it is not necessary to add a strong beam structure to hold the cable reel 40, thus suppressing weight increase. Furthermore, since the cable reel 40 can be contained within the width of the upper slewing body 3 and does not protrude from the upper slewing body 3 when viewed from above, the cable reel 40 does not obstruct the operator's view even when the upper slewing body 3 is slewing, improving visibility. In addition, it is possible to prevent the front work implement 22 from coming into contact with the cable reel 40, thus achieving the same effects as the first embodiment.

[0041] Furthermore, although slip rings 47 and 52 are required in this embodiment, there is no need to fix the winding direction of the power transmission cable 37, similar to the first embodiment. Therefore, the winding direction of the power transmission cable 37 can always be directed towards the power supply unit PS, thereby preventing damage caused by bending of the power transmission cable 37.

[0042] Next, a third embodiment shown in Figure 5 will be described. Parts similar to those in each embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0043] In this embodiment, the cable reel 40 is positioned approximately concentrically with the pivot center of the upper swivel body 3 and located between the track frames 6 at the lower part of the main frame 7 of the lower running body 2. That is, the cable reel 40, which is sized to fit within the width between the left and right tracks 14, is positioned below the swivel joint 28 and at the lower part of the main frame 7 of the lower running body 2, approximately concentrically with the swivel bearing 25. The cable reel 40 is suspended from the lower part of the lower running body 2 (main frame 7) via a bearing 41 having the same structure as in the first embodiment, for example.

[0044] A gear section 42 is formed at the lower part of the lower traveling body 2, and a motor 43 that meshes with the gear section 42 is attached to the cable reel 40. In this example, the motor 43 is an electric motor. By driving the motor 43, the cable reel 40 can rotate independently of the lower traveling body 2. If the motor 43 is a hydraulic motor, for example, the gear section 42 may be placed on the cable reel 40 side and the motor 43 on the lower traveling body 2 side.

[0045] Furthermore, the end of the power transmission cable 37 wound around the cable reel 40 is inserted through the wiring insertion hole 50 of the swivel joint 28 and electrically and mechanically connected to a slip ring 52 coaxially positioned on the upper part of the swivel joint 28. The slip ring 52 is then electrically connected to a power receiving unit such as the electric motor 35 inside the upper slewing body 3 via wiring 53. Thus, the power transmission cable 37 is electrically connected to the power receiving unit via the slip ring 52, and power is supplied to the power receiving unit from the power supply unit PS. Therefore, in this embodiment, as in the first embodiment, only one slip ring 52 is needed to electrically connect the power transmission cable 37 to the power receiving unit inside the upper slewing body 3. However, since the cable reel 40 is located between the track frames 6, the winding direction of the power transmission cable 37 cannot always be oriented towards the power supply unit PS, and the winding direction of the power transmission cable 37 is basically fixed between the track frames 6. Therefore, it is desirable to provide a guide to prevent the power transmission cable 37 from coming into contact with the tracks 14.

[0046] Preferably, the bearing 41 and the swivel joint 28 are connected by a flexible joint 55. The flexible joint 55 has, for example, a flexible tube connected to the bearing 41 and a flexible tube connected to the swivel joint 28, which are arranged coaxially, and a pin that fixes them together, with the pin passing radially through both tubes to loosely fix them together. A power transmission cable 37 is inserted inside the tubes.

[0047] As described above, by having a configuration similar to the first embodiment, such as positioning the cable reel 40 substantially concentrically with the pivot center of the upper slewing body 3, this embodiment allows the cable reel 40 to be mounted on the existing main frame 7 of the lower traveling body 2 via the bearing 41. Therefore, it is not necessary to add a strong beam structure to hold the cable reel 40, thus suppressing weight increase. Furthermore, since the cable reel 40 can be contained within the width of the upper slewing body 3 and does not protrude from the upper slewing body 3 when viewed from above, the cable reel 40 does not obstruct the operator's view even when the upper slewing body 3 is slewing, improving visibility. In addition, it is possible to prevent the front work implement 22 from coming into contact with the cable reel 40, thus achieving the same effects as the first embodiment.

[0048] Furthermore, since the cable reel 40 is suspended from the lower traveling body 2 (main frame 7), there is no need to take up vertical space between the lower traveling body 2 and the upper rotating body 3 to position the cable reel 40, thus reducing the overall height of the work machine 1.

[0049] Furthermore, in this embodiment, the cable reel 40, the power transmission cable 37, the rotating part of the bearing 41, the flexible joint 55, and the rotating part of the slip ring 52 rotate together as a single unit. The torque of the cable reel 40 is transmitted to the slip ring 52. The weight of these components is supported by the bearing 41, which connects the cable reel 40 to the lower running body 2 (main frame 7). Even if there is some misalignment of the central axes of the swivel joint 28, bearing 41, and pivot bearing 25, the misalignment can be absorbed by arranging flexible structures such as the soft cable tube housing the power transmission cable 37 and the flexible joint 55.

[0050] Furthermore, since only one expensive slip ring 52 is needed, the work machine 1 can be constructed at a low cost.

[0051] Furthermore, although the cable reel 40 needs to be large enough to fit within the width between the left and right tracks 14, the absence of a swivel bearing 25 inside the cable reel 40 allows for a smaller inner diameter, ensuring sufficient cable length.

[0052] In each embodiment, the lower traveling body 2 may be provided with a cover that covers the cable reel 40 from below. Alternatively, for example, the bearing 41 of the cable reel 40 may be located at the bottom of the lower traveling body 2 (main frame 7), and the cable reel 40 may be located inside the frame 5 of the lower traveling body 2.

[0053] The power receiving unit supplied from the power transmission cable 37 is not limited to the electric motor 35, but may be any other power receiving unit mounted on the upper rotating body 3. In that case, the hydraulic pump 34 is not limited to one driven by the electric motor 35, but may also be driven by an engine. [Industrial applicability]

[0054] This invention can be used, for example, in industries that manufacture and sell wired electric power machinery. [Explanation of symbols]

[0055] 1. Working Machinery 2 Lower running body 3. Upper rotating body 22 Front work machine, which is a work device. 34 Hydraulic pump 35. The electric motor, which is the power receiving unit. 37 Power transmission cables 40 Cable Reels 47, 52 Slip rings PS power supply section

Claims

1. Lower running body and An upper rotating body is supported on top of this lower traveling body so as to be able to rotate, A cable reel is positioned approximately concentrically with the pivot center of this upper rotating body, and is capable of winding and unwinding a power transmission cable for supplying power to the power receiving unit by rotation. A work machine characterized by being equipped with the following features.

2. It is equipped with only one slip ring for electrically connecting the power transmission cable and the power receiving unit. The work machine according to claim 1, characterized by its features.

3. The cable reel is positioned between the lower traveling body and the upper rotating body, and its rotation angle is controlled so that the winding direction of the power transmission cable faces the power supply unit. The work machine according to claim 1, characterized by its features.

4. The upper rotating body is equipped with a work device that is operably positioned on it. The work machine according to claim 1, characterized by its features.

5. A hydraulic pump that discharges hydraulic fluid, The electric motor, which is the power receiving unit that drives the hydraulic pump, is powered via a power transmission cable, The work machine according to claim 1, characterized by comprising the following:

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