JP6687984B2 - Open leg hydraulic excavator - Google Patents

Description

  According to the present invention, it is possible to widen the space between the front portions of the left and right crawler type traveling devices to open the left and right traveling devices in a V-shape, and to excavate the region between the front parts of the left and right traveling devices. Leg-type hydraulic excavator. For example, the present invention relates to an open leg hydraulic excavator for excavating work by changing the position in small increments by a traveling body at the bottom of a vertical hole (deep foundation pile hole) into which a deep foundation pile is inserted by the deep foundation method.

  For example, in the deep foundation method of constructing a deep foundation pile (foundation) of a new steel tower deep in the ground when rebuilding a steel tower such as a power transmission line in a mountainous area, a small diameter vertical hole for inserting the deep foundation pile is drilled. To do. However, in the excavation work of vertical holes in mountainous areas, it is often impossible to secure a carry-in route and a wide scaffolding, so that large-scale mechanical equipment cannot be used. In such a case, for example, a disassembled excavator or a micro hydraulic excavator that can be transported by a helicopter may be used. It is a method of assembling a disassembly type shovel on site and excavating a vertical hole from the surface to a certain depth, and then inserting a micro hydraulic excavator into the vertical hole with a crane to dig the vertical hole.

  However, inside a vertical hole with a small diameter (for example, a diameter of about 2.5 m), no matter how small the hydraulic excavator is, the area that can be actually excavated by its own moving body that touches the bottom of the vertical hole is small Since the position and direction of the traveling body must be changed, the work cannot be efficiently performed. Therefore, as described in Patent Document 1, a hydraulic pressure that allows the front and rear legs of the crawler belt type left and right traveling devices to open in a V-shape and excavates a region between these left and right traveling devices. I have a shovel. Hereinafter, this type of hydraulic excavator will be referred to as an "open leg hydraulic excavator".

Japanese Utility Model Publication No. 59-102654

  The open-leg hydraulic excavator described in Patent Document 1 connects left and right traveling devices to the center frame of a truck frame via links, and travels left and right with a single hydraulic cylinder that connects the left and right links. This is a configuration in which the device is opened. For example, when an outrigger is installed in the rear part of the center frame to suppress the rearward leaning of the machine, extending the hydraulic cylinder with the outrigger touching the ground and the center frame being fixed to the ground will cause left and right leg movements of the traveling device. Can cause variations. For example, when the right traveling device is caught on the ground and is restrained, only the traveling device on the left side, which has a low operation resistance, opens as the cylinder extends. In this way, when there is a difference in the leg angle between the left and right traveling devices, one of the traveling devices opens the legs excessively, and when the rear outrigger is provided as described above, one of the traveling devices may interfere with the outriggers. There is a nature.

  An object of the present invention is to prevent the travel of one traveling device from being excessively opened in an open-leg hydraulic excavator in which the distance between the front portions of the left and right traveling devices of the crawler belt type is enlarged and the legs are opened in a V-shape. Is.

  In order to achieve the above object, the present invention provides a traveling body, a revolving structure provided on the traveling structure so as to be rotatable, a working machine attached to the revolving structure, a hydraulic actuator for driving the working machine, and the hydraulic actuator. A hydraulic pump that discharges pressure oil that drives the hydraulic pump, and a prime mover that drives the hydraulic pump, wherein the traveling body is a center frame that supports the revolving structure, and the traveling frame is rotatably connected to the center frame. Of the left and right running devices that can open the legs in a V-shape by expanding the front part of the vehicle, left and right links that respectively connect the center frame and the left and right running devices, and the left and right links that connect the left and right links. In an open-leg hydraulic excavator including a cylinder that opens and closes a traveling device, the excavator is disposed between an upper surface plate and a lower surface plate of the center frame and has the left and right links or the front plate. The cylinder is provided with left and right stoppers having elongated holes through which connecting pins are passed, and left and right support shafts provided on both left and right side portions of the center frame for horizontally rotatably supporting the left and right stoppers. The maximum opening angle of each of the left and right traveling devices is individually limited by restraining the connecting pin with the elongated hole of the stopper.

  ADVANTAGE OF THE INVENTION According to this invention, in the open-leg type hydraulic excavator which widens the space | interval of the front part of a crawler-type left and right traveling device, and suppresses one traveling device from excessively opening a leg. You can Thus, even if an outrigger or the like is provided on the rear portion, it is possible to prevent the traveling device from interfering with the outrigger.

It is a side view showing the whole open leg hydraulic excavator composition concerning one embodiment of the present invention, and showing the open leg hydraulic excavator which attached the bucket as an attachment. It is a side view showing the whole open leg hydraulic excavator composition concerning one embodiment of the present invention, and showing the open leg hydraulic excavator which attached the breaker as an attachment. FIG. 2 is a plan view of a traveling body of the open leg hydraulic excavator shown in FIG. 1. It is the figure which looked at the left part of the center frame of the running body shown in Drawing 3 from the front. It is a top view showing the mode of the open-leg type hydraulic excavator shown in FIG. 1 which works by closing a leg at the bottom of a vertical hole. It is a top view showing the mode of the open-leg type hydraulic excavator shown in FIG. 1 which opens and works in the bottom part of a vertical hole. FIG. 4 is a plan view of the traveling body shown in FIG. 3 in which the left and right traveling devices have different leg opening motion resistances and only the right traveling device is opened. FIG. 2 is a plan view of the open leg hydraulic excavator shown in FIG. 1 in a state where the left and right traveling devices have different opening leg resistances and only the right traveling device is opened.

  Embodiments of the present invention will be described below with reference to the drawings.

1. Open Leg Hydraulic Excavator FIGS. 1 and 2 are side views showing the overall configuration of an open leg hydraulic excavator according to an embodiment of the present invention. Note that FIG. 1 shows an open leg hydraulic excavator with a bucket attached as an attachment, and FIG. 2 shows an open leg hydraulic excavator with a breaker attached as an attachment. In the following description, the term "hydraulic excavator" is used to refer to an open leg hydraulic excavator unless otherwise specified. The front side (left side in the figure) of the driver's seat of the hydraulic excavator 100 in FIG. 1 is referred to as the front side.

  The hydraulic excavator 100 is put into a vertical hole (deep foundation pile hole) H into which a deep foundation pile (not shown) is inserted, for example, by the deep foundation method, and excavation work is performed while changing the position in small steps by the traveling body at the bottom of the vertical hole. , A working machine for digging a vertical hole. The hydraulic excavator 100 includes a traveling body 10, a swing body 30, and a working machine (front working machine) 40.

2. The traveling body 10 is a crawler type (crawler type) traveling body for the hydraulic excavator 100 to travel by itself, and includes a track frame 11, left and right traveling devices 12, and an outrigger 13. The track frame 11 forms a frame of the traveling body 10, and includes a center frame 14 (FIG. 3), left and right links 15 (FIG. 3), and left and right side frames 16, so that the track frame 11 has an H shape in plan view when the legs are closed. Has been formed. The outrigger 13 is provided on the rear portion (right side portion in FIG. 1) of the center frame 14. Since the outrigger is not provided in the front part of the center frame 14 because it may interfere with excavation work, the outrigger 13 is provided only in the rear part. The outrigger 13 swings up and down by a cylinder (not shown), and its height can be adjusted according to the scene to suppress the rearward tilt of the hydraulic excavator 100 during work. Details of the configuration of the track frame 11 will be described later.

  The left and right traveling devices 12 include driven wheels 21, drive wheels 22, crawler tracks 23, and a traveling motor 24. The driven wheel 21 is rotatably supported at the front ends (left ends in FIG. 1) of the left and right side frames 16 of the track frame 11, and the drive wheels 22 are rotatably supported at the rear ends (right end in FIG. 1) of the left and right side frames 16. ing. The left and right side frames 16 of the track frame 11 also serve as the frames of the left and right traveling devices 12, respectively. The crawler belts 23 are respectively wound around the driven wheels 21 and the drive wheels 22 in the left and right traveling devices 12. In the left and right traveling devices 12, the output shaft of the traveling motor 24 is connected to the rotary shafts of the drive wheels 22, respectively. When the traveling motor 24 is driven, the crawler belt 23 wound around the driven wheel 21 and the driving wheel 22 is circularly driven, and the traveling operation of the hydraulic excavator 100 and the like are performed. The traveling motor 24 is a hydraulic motor. In the case of the hydraulic excavator 100 of the present embodiment, the length of the traveling device 12 in the longitudinal direction (at least the length of the side frame 16) is shorter than that of a general hydraulic excavator, because it moves around at the bottom of the small-diameter vertical hole H. The length is the same as or shorter than the length of the revolving structure 30 in the front-rear direction. Particularly, in the present embodiment, when the left and right traveling devices 12 are parallel to each other (when the legs are closed as shown in FIG. 5), the outer sides of the left and right traveling devices 12 in the vehicle width direction are substantially opposite square sides in a plan view. The distance and length of the traveling device 12 are adjusted so that As a result, stability is ensured despite the short traveling device 12.

3. Revolving structure The revolving structure 30 includes a revolving frame (not shown), a driver's seat 32, a counterweight 33, a machine room 34, and the like. The revolving frame is a base frame of the revolving structure 30, and is provided above the track frame 11 (center frame 14) via the revolving wheel 25. A revolving motor (not shown) is mounted near the revolving wheel 25 on the revolving frame, and an output shaft of the revolving motor meshes with a gear provided on the revolving wheel 25, so that the revolving structure 30 with respect to the traveling body 10 is provided. Turn around the vertical axis. Although an electric motor can be used as the swing motor, a hydraulic motor is used in this embodiment.

  The driver's seat 32 is arranged at a position offset to one side in the left-right direction (left side in the present embodiment) with respect to the turning center of the turning body 30. The upper side of the driver's seat 32 is covered with a canopy 35. Further, an operating device 36 is arranged at the front of the revolving frame so as to be located in front of the driver's seat 32. The operation device 36 is a plurality of operation devices such as a lever device and pedals for instructing the operation of the work machine 40, the traveling body 10, and the revolving structure 30. The counterweight 33 is a weight for balancing the weight with the working machine 40, and is provided at the rear end of the revolving frame. The counterweight 33 in the present embodiment is formed integrally with a cover (outer wall) of the machine room 34 (also serves as a cover), and covers each device housed in the machine room 34. Further, the hydraulic excavator 100 is ultra-small, and among the columns supporting the canopy 35, the column 35a arranged at the rear part of the revolving structure 30 stands up from the upper part of the counterweight 33 or a cover (not shown) thereon, and the revolving structure 30 moves. Located near the rear end of the.

  Although not shown, the machine chamber 34 accommodates a motor 37, a hydraulic pump, a cooling fan, a valve unit, a hydraulic oil tank, a fuel tank, a controller 38, and the like. The electric motor 37 is a prime mover that drives a hydraulic pump, and is driven by, for example, electric power supplied via a cable (not shown) from a generator separate from the hydraulic excavator 100. However, instead of receiving a power supply from an external power source, a power source (a generator, a battery, etc.) may be mounted in the machine room 34. The hydraulic pump driven by the electric motor 37 sucks the hydraulic oil in the hydraulic oil tank and discharges it as pressure oil. The pressure oil discharged from the hydraulic pump is supplied to the corresponding hydraulic actuator under the control of a valve unit that operates according to the operation of the operating device 36. The controller 38 is a control device that controls electrical components. The hydraulic excavator 100 of the present embodiment is ultra-compact as shown in FIG. 1, and the layout of the equipment accommodated in the machine room 34 is arranged such that the controller 38 and the electric motor 37 are arranged vertically below the driver seat 32. The revolving structure 30 has an extremely small diameter by being three-dimensionally devised. In this embodiment, the controller 38 is arranged above the electric motor 37. Although not particularly shown, the driver seat 32 has a structure in which the rear part rotates up and down with the front part as a fulcrum. When the rear part of the driver seat 32 is lifted and tilted, the upper side of the controller 38 is opened and the controller 38 is opened. 38 is accessible.

4. Working Machine The working machine 40 is a multi-joint type front working machine including a working arm 41 and a working tool 44 that is an attachment, and is attached to the revolving structure 30. The working arm 41 includes a boom 42, an arm 43, a boom cylinder (not shown), an arm cylinder 46, and a working tool cylinder 47. The boom 42 is rotatably connected to the front part of the revolving structure 30, the arm 43 is rotatably connected to the tip of the boom 42, and the work tool 44 is rotatably connected to the tip of the arm 43. The boom 42, the arm 43, and the work tool 44 all rotate about a rotary shaft that extends horizontally to the left and right. Although FIG. 1 shows an example in which a bucket is mounted as the work tool 44 and a breaker is mounted as the work tool 44 in FIG. 2, other attachments can also be mounted. Both ends of the boom cylinder are connected to the revolving structure 30 and the boom 42, and the arm cylinder 46 is connected to the boom 42 and the arm 43. The work tool cylinder 47 has a base end connected to the arm 43, and a tip end connected to a tip end portion of the arm 43 and the work tool 44 via a link 48. The boom cylinder, the arm cylinder 46, and the work implement cylinder 47 are all hydraulic actuators, which are driven by the pressure oil discharged from the hydraulic pump and drive the work machine 40 by the expansion and contraction operation.

5. Track Frame FIG. 3 is a plan view of the traveling body of the hydraulic excavator shown in FIGS. 1 and 2, and FIG. 4 is a view of the left side portion of the center frame as seen from the front. FIG. 3 shows a state in which the front part of the left and right traveling devices 12 is widened (the rear part is narrowed) and the left and right traveling devices 12 are opened in a V-shape. Further, for clarity of the structure, the upper plate 52 (FIG. 4) on the center frame to which the swivel wheel 25 is attached is not shown. As described above, the track frame 11 includes the center frame 14, the link 15 and the side frame 16 (FIGS. 1 and 2).

  The center frame 14 is a main frame of the track frame 11, and links 15 and side frames 16 are connected to both left and right sides thereof, and a revolving structure 30 is supported on an upper portion thereof. The center frame 14 includes a lower surface plate 51, an upper surface plate 52 (FIG. 4), a front surface plate 53, a rear surface plate 54, a left side surface plate 55, and a right side surface plate 56. The front surface plate 53, the rear surface plate 54, the left side surface plate 55, and the right side surface plate 56 are plate members that are vertically erected. The center frame 14 has a structure in which a square frame having front, rear, left, right, and right side plates 53, 55, and 56 as front, rear, left, and right sides is sandwiched from above and below by a horizontal bottom plate 51 and a top plate 52. . The lower surface plate 51, the upper surface plate 52, the front surface plate 53, the rear surface plate 54, the left side surface plate 55, and the right side surface plate 56 are fixed to each other by welding or the like.

  The left and right links 15 are arranged at a height between the lower surface plate 51 and the upper surface plate 52 of the center frame 14, and have a first arm 58 and a second arm 59, respectively. The base end of the first arm 58 is connected to the lower surface plate 51 and the upper surface plate 52 of the center frame 14 via a vertically extending rotation shaft 61, and the first arm 58 is horizontal with respect to the center frame 14 about the rotation shaft 61. It can be rotated along. The rotation shafts 61 of the left and right links 15 are located on the left and right of the front portion of the center frame 14, respectively. The second arm 59 has a base end portion connected to the distal end portion of the first arm 58 via a vertically extending rotary shaft 62, and the second arm 59 extends along the horizontal plane with respect to the first arm 58 about the rotary shaft 62. It is rotatable. The tip end portion of the second arm 59 is connected to a bracket 64 protruding inward in the vehicle width direction from the front portion of the side frame 16 (FIG. 1, etc.) of the track frame 11 via a vertically extending rotary shaft 63. . Therefore, the second arm 59 is also rotatable along the horizontal plane with respect to the side frame 16 with the rotation shaft 63 as a fulcrum. Further, brackets 65 protruding inward in the vehicle width direction are provided at the rear portions of the left and right side frames 16, respectively. The bracket 65 is arranged at a height between the lower surface plate 51 and the upper surface plate 52 of the center frame 14, and is connected to the lower surface plate 51 and the upper surface plate 52 via a vertically extending rotating shaft 66, and the rotating shaft 66 is connected to the bracket 65. It is rotatable about a center frame 14 along a horizontal plane. These rotating shafts 66 are located on the left and right of the rear portion of the center frame 14, respectively. Reinforcing plates 68 are provided on the left and right sides of the center frame 14 at positions on the front side of the rotating shaft 61 and on the front side of the rotating shaft 66, respectively. These four reinforcing plates 68 are vertically extending members that extend to the left and right, and connect the lower surface plate 51 and the upper surface plate 52.

  As described above, the brackets 65 of the side frames 16 are directly connected to the center frame 14 at the rear parts of the left and right traveling devices 12, while the brackets 64 of the side frames 16 are centered at the front parts of the left and right traveling devices 12 via the links 15. It is connected to the frame 14. As a result, the left and right traveling devices 12 can be horizontally rotated about the rotation shaft 66 to widen the interval between the front parts and narrow the interval between the rear parts to open the V-shaped legs. You can do it.

  The rotary shafts 62 of the left and right links 15 are connected by a single cylinder 67. The cylinder 67 extends to the left and right, and is arranged through openings provided in the left side face plate 55 and the right side face plate 56 of the center frame 14. The left-right dimension of the lower plate 51 and the upper plate 52 is set so as to cover the whole or most of the cylinder 67 which is extended to the maximum. As the cylinder 67 expands and contracts, the left and right traveling devices 12 open and close in a V-shape as shown in FIG. 3 (the left and right traveling devices 12 both extend forward and backward and are parallel to each other). become). FIG. 5 is a plan view showing a state of the hydraulic excavator 100 which is closed at the bottom of the vertical hole H to work, and FIG. 6 is a plan view showing a state of the hydraulic excavator 100 which is opened at the bottom of the vertical hole H to work. Indicated.

6. Stopper A stopper 70 is arranged between the lower surface plate 51 and the upper surface plate 52 of the center frame 14. The left and right stoppers 70 are rod-shaped, horizontal flat plate-shaped members, and have elongated holes 72 through which the connecting pins are inserted. The long hole 72 extends in the longitudinal direction of the stopper 70 and opens vertically. In the present embodiment, the rotating shaft 62 that connects the left and right links 50 and the cylinder 67 is used as the connecting pin passing through the long hole 72. These stoppers 70 are horizontally rotatably connected to the center frame 14 by left and right support shafts 71 provided separately from the rotating shaft 66. The left and right support shafts 71 extend vertically, and the upper portion is supported by the upper surface plate 52 of the center frame 14 and the lower portion is supported by a bracket 69 (FIG. 3) provided on a reinforcing plate 68 described later. However, when the support shaft 71 is extended to penetrate the upper plate 52 and the lower plate 51 of the center frame 14 and the upper and lower sides of the support shaft 71 are supported by the upper plate 52 and the lower plate 51, the bracket 69 can be omitted. The left and right support shafts 71 are located on the front and rear sides of the rotary shaft 66 in the left and right sides of the rear portion of the center frame 14, and are separated from the rotary shaft 66 by the reinforcing plate 68.

  With such a configuration, in the present embodiment, the maximum opening angle of the left and right traveling devices 12 is individually limited by restraining the rotary shaft 62 by the elongated hole 72 of the stopper 70. In the present embodiment, the individual maximum open leg angle of the left and right traveling devices 12 is about 45 degrees with respect to the center line extending in the front and rear of the center frame 14, and the relative maximum open leg angle of the left and right traveling devices 12 is approximately. It is 90 degrees. Thus, as shown in FIG. 3, even if the left and right traveling devices 12 are fully opened, the traveling device 12 does not interfere with the outriggers 13. The grounding portion of the outrigger 13 is also formed in a right-angled triangle shape along with the rear edges of the left and right traveling devices 12 when the legs are fully opened.

7. Operation When excavating the vertical hole H as a deep foundation pile hole of a steel tower in a mountainous area, for example, the disassembly type hydraulic excavator assembled on site excavates the vertical hole H to a certain depth from the ground surface, and then the hydraulic excavator 100 is excavated by a crane or the like. Is charged into the vertical hole H. When operating the hydraulic excavator 100, the operator sits in the driver's seat 32 and operates the operation device 36 as appropriate. This allows the traveling body 10 to move the hydraulic excavator 100, the work machine 40 to perform excavation work, and the revolving structure 30 to revolve. For the excavation work, for example, as shown in FIG. 1, a bucket is used as the work tool 44 to dig the bottom of the vertical hole H, or if necessary, a breaker is used as the work tool 44 as shown in FIG. Crush the bedrock on the bottom. The excavated earth and sand, gravel, etc. are scooped with a bucket, loaded into a separately prepared container, and the container is lifted with a crane or the like and carried out of the vertical hole H.

  For example, when it is necessary to open the legs and excavate the region between the left and right traveling devices 12, the operator in the driver's seat 32 appropriately operates to extend the cylinder 67. At this time, if there is no bias in the operation resistance of the leg opening operation of the left and right traveling devices 12, both traveling devices 12 rotate as the cylinder 67 extends, and as shown in FIG. 3 and FIG. Open legs. However, in the case where the left and right traveling devices 12 are biased in the operating resistance of the open leg, the traveling device 12 having a relatively smaller operating resistance is opened first. The operation in that case will be described below.

  FIG. 7 is a plan view of the traveling body 10 in a state where the left and right traveling devices have different leg opening motion resistances and only the right traveling device is opened, and FIG. 8 is a plan view of the hydraulic excavator 100 in that state. FIG. 7 is a view corresponding to FIG. 3 and FIG. 8 is a view corresponding to FIG. 5 and FIG. In the example of FIG. 7 and FIG. 8, it is assumed that the left traveling device 12 is caught on the ground and the operation resistance of the leg opening operation is larger than that of the right traveling device 12, for example. In the state where the left and right traveling devices 12 are closed as shown in FIG. 5, the rotary shaft 62 is located on the innermost side in the vehicle width direction in its own movement range. In the example of FIG. 7, as shown for the traveling device 12 on the left side, when the legs are closed, the rotary shaft 62 is located at a position side by side with the rotary shafts 61 and 66. When the cylinder 67 is extended from this state, the rotary shaft 62 of the traveling device 12 on the right side, which has a low resistance to open legs, moves outward in the vehicle width direction, and the stopper 70 engages with the rotary shaft 62 in the elongated hole 72. Rotate outward in the vehicle width direction. When the rotary shaft 62 reaches the end of the elongated hole 72 of the stopper 70 (the end opposite to the support shaft 71), the rotary shaft 62 is constrained by the stopper 70. In this way, when the right traveling device 12 is fully opened, the left traveling device 12 is not fully extended and the extension amount of the cylinder 67 is still left, but the right traveling device 12 is further extended. There is no. When the cylinder 67 is further extended thereafter, the magnitude relationship of the operating resistance is reversed by the restraint of the right-side traveling device 12, and the left-side traveling device 12, which has become smaller, opens its legs and finally shown in FIG. As described above, the left and right traveling devices 12 open the legs to the maximum angle.

8. Effects (1) According to the present embodiment, first, the traveling device 12 can be opened into a V-shape, so that the legs are opened to excavate between the left and right traveling devices 12 and the left and right crawler belts 23 are rotated in reverse. By doing so, it is possible to laterally move in an arc shape at the bottom of the vertical hole H. Therefore, even in a narrow vertical hole H, a small turn can be made, and even if an appropriate distance cannot be taken from the excavation site, the excavation can be performed to the lower part of the front part of the revolving structure 30, so that the work can be efficiently performed.

  At this time, in the ultra-compact hydraulic excavator 100, the traveling body 10 is also small, and the left and right traveling devices 12 are individually connected to the center frame 14 by cylinders (that is, the left and right traveling devices 12 are provided with their own cylinders). There is not enough layout margin to make up the structure. Since the left and right traveling devices 12 are opened by the single cylinder 67, for example, as described above, the right traveling device is caught on the ground and is restrained. Only the lower left-hand drive opens. If the left and right traveling devices 12 have different leg opening angles, one traveling device 12 may excessively open the leg, and the one traveling device 12 may interfere with the outrigger 13 provided at the rear portion.

  Therefore, in the present embodiment, the stoppers 70 that individually limit the leg opening angles of the left and right traveling devices 12 are provided. As a result, in the open leg hydraulic excavator 100 in which the front portions of the left and right crawler type traveling devices 12 are widened, one traveling device 12 is prevented from being excessively opened. be able to. As a result, the traveling device 12 can be prevented from interfering with the outriggers 13 and the like provided on the rear portion.

  (2) In order to secure the structural strength of the center frame 14, a member such as the reinforcing plate 68 is needed as needed. If the stopper 70 is connected to the center frame 14 by the rotating shaft 66, if the stopper 70 is arranged between the lower surface plate 51 and the upper surface plate 52 of the center frame 14, the stoppers that engage with the rotating shafts 62 and 66 are engaged. 70 interferes with the reinforcing plate 68. Therefore, when the rotary shaft 66 is extended above the upper surface plate 52 of the center frame 14 and the stopper 70 is arranged above the upper surface plate 52, interference between the stopper 70 and the reinforcing plate 68 can be avoided, but in that case, the rotary shaft 62 is moved upward. It interferes with the face plate 52. Further, when the stopper 70 is arranged on the upper side of the center frame 14, the upper surface plate 52 has to be cut out in order to allow the movement of the rotating shaft 62, which reduces the structural strength of the center frame 14. The same applies when the rotary shaft 66 is extended below the lower surface plate 51 of the center frame 14 and the stopper 70 is arranged below the lower surface plate 51. In particular, when the stopper is arranged on the lower side of the center frame 14, when the area of the lower surface plate 51 is reduced due to the notch, the lower surface plate 51 protects the cylinder 67 and the like from the gravel and the like that jumps up from the ground during the work. Structurally disadvantageous.

  Therefore, in the present embodiment, the support shaft 71 is provided separately from the rotating shaft 66, and the stopper 70 is supported by the dedicated support shaft 71 so as to avoid the interference with the reinforcing plate 68 and the lower surface plate of the center frame 14. A stopper 70 can be arranged between the 51 and the top plate 52. As a result, it is not necessary to cut out the lower plate 51 and the upper plate 52, and it is possible to suppress deterioration of the strength of the center frame 14 and the protective function of the cylinder 67.

  (3) Since the rotating shaft 62 that connects the first arm 58 and the second arm 59 of the left and right links 15 also serves as a connecting pin that passes through the elongated hole 72 of the stopper 70, the configuration can be simplified and the number of parts can be suppressed. To be

  (4) In this embodiment, the left and right traveling devices 12 are not directly connected by the cylinder 67, but the left and right links 15 are connected by the cylinder 67. Thereby, the expansion / contraction operation of the cylinder 67 can be efficiently converted into the rotational movement of the traveling device 12, and the length and stroke of the cylinder 67 can be suppressed.

9. Modifications In the above embodiment, in order to obtain the above effect (2), the stopper 70 is connected to the center frame 14 by the dedicated support shaft 71 in addition to the rotation shaft 60 which is the rotation support point of the traveling device 12. However, the structure is not necessarily limited to this as long as the essential effect (1) is obtained. For example, when the structural strength of the center frame 14 can be sufficiently secured without the reinforcing plate 68, the stopper 70 may be connected to the center frame 14 by the rotating shaft 66. Further, in order to obtain the above effect (3), the connecting pin passing through the elongated hole 72 of the stopper 70 is also used as the rotating shaft 62 of the link 15, but the connecting pin may move as the cylinder 67 expands and contracts. Therefore, a dedicated connecting pin provided separately from the rotary shaft 62 on the other parts of the left and right links 15 (for example, the first arm 58 and the second arm 59) or the other parts of the cylinder 67 (for example, the ends of the tube and the rod). It is also possible to have a structure in which

  Further, if it can be installed, there may be a plurality of cylinders 67. In this case, the left and right traveling devices 12 can be individually rotated by different cylinders, but it is conceivable that a cylinder unit in which a plurality of cylinders are connected and a stroke amount is increased is replaced with the cylinder 67. .

  Further, the case where the invention is applied to the hydraulic excavator 100 equipped with the electric motor 37 as a prime mover for driving the hydraulic pump has been described as an example. However, when the hydraulic excavator 100 can be operated remotely, or when exhaust gas does not pose a problem at the operating site, an engine (internal combustion engine) may be used as a prime mover instead of the electric motor 37.

DESCRIPTION OF SYMBOLS 10 ... Running body, 12 ... Running device, 14 ... Center frame, 15 ... Link, 30 ... Revolving body, 37 ... Electric motor (motor), 40 ... Working machine, 46 ... Arm cylinder (hydraulic actuator), 47 ... Working tool cylinder (Hydraulic actuator), 51 ... bottom plate, 52 ... top plate, 62 ... rotating shaft (connecting pin), 67 ... cylinder, 70 ... stopper, 71 ... support shaft, 72 ... oblong hole, 100 ... open leg hydraulic excavator

Claims (3)

A traveling body, a revolving structure provided on the traveling structure so as to be revolvable, a working machine attached to the revolving structure, a hydraulic actuator for driving the working machine, a hydraulic pump for discharging pressure oil for driving the hydraulic actuator, and A center frame that supports the revolving structure, and includes a prime mover that drives the hydraulic pump, and the traveling structure is rotatably connected to the center frame so that a space between front portions of the traveling structure is enlarged to form a V-shape. And left and right traveling devices capable of opening legs, left and right links respectively connecting the center frame and the left and right traveling devices, and a cylinder for connecting the left and right links to open and close the left and right traveling devices. In open leg hydraulic excavator,
Left and right stoppers that are arranged between the upper and lower plates of the center frame and that have elongated holes through which the connecting pins provided on the left and right links or the cylinder are inserted,
The center frame includes left and right support shafts that are provided on both left and right sides of the center frame and support the left and right stoppers so as to be horizontally rotatable.
An open leg hydraulic excavator, wherein the maximum open leg angle of each of the left and right traveling devices is individually limited by restraining the connecting pin with the elongated hole of the stopper.   The open leg hydraulic excavator according to claim 1, wherein the left and right support shafts are different from a rotation shaft that rotatably supports the left and right traveling devices with respect to the center frame. Leg type hydraulic excavator.   The open leg hydraulic excavator according to claim 1, wherein the left and right connecting pins are rotary shafts that connect the left and right links and the cylinder.

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