JP6585532B2 - Small excavator - Google Patents

Description

  The present invention relates to a small hydraulic excavator that performs excavation work in a narrow work site such as an urban area, and more particularly, to a small hydraulic excavator provided with a work front swingable in the left-right direction on the front side of an upper swing body.

  In general, a hydraulic excavator used for earth and sand excavation work is provided with a self-propelled lower traveling body, an upper revolving body that is pivotably mounted on the lower traveling body, and an upside-down movable structure on the front side of the upper revolving body. And a working front.

  Here, as a small hydraulic excavator (mini excavator) suitably used in a narrow work site such as an urban area, a swing type hydraulic excavator in which a work front can swing (swing) in the left-right direction is known. This swing-type hydraulic excavator includes a swing post supported on the front side of the upper swing body so as to be swingable in the left-right direction, and the work front is attached to the swing post.

  Accordingly, the swing-type hydraulic excavator swings the swing post to one side in the left-right direction (for example, the left side) and swings the upper swing body to the other side in the left-right direction (for example, the right side) to It can be translated in the direction. For this reason, the side groove extending along the road can be excavated by repeating the excavation work using the work front held in a parallel posture while running the lower traveling body.

  By the way, in order to improve the safety of civil engineering work using a hydraulic excavator, a hydraulic excavator for detecting an operator existing around the hydraulic excavator by a detecting means such as a laser radar attached to the upper swing body has been proposed. . When the operator detected by the detection means is present in a remote area away from the hydraulic excavator, this hydraulic excavator reduces the discharge flow rate of the hydraulic pump and restricts the operation of the actuator. Can be aroused. On the other hand, when the operator detected by the detection means is in a near region near the hydraulic excavator, the discharge flow rate of the hydraulic pump is reduced and the pilot pressure is reduced to limit the operating speed of the hydraulic actuator. Thus, the operator can be alerted and the safety for the operator can be ensured (see Patent Document 1).

JP 2014-218849 A

  Here, in a medium-class hydraulic excavator used in a wide work site, the operator sitting on the driver's seat has low visibility on the right side and the rear side of the vehicle body. Technology is effective.

  However, since a swing-type small hydraulic excavator is generally used in a narrow work site such as an urban area, it does not only perform excavation work in the vicinity of obstacles such as houses and side walls, but also around the excavator. An operator often performs work. For this reason, as in the prior art of Patent Document 1, if the operation of the hydraulic excavator is restricted immediately when an obstacle or other worker existing around the hydraulic excavator is detected, a small size can be achieved at a narrow work site. There is a problem that work efficiency is reduced when a hydraulic excavator is used.

  In particular, in urban areas or the like, side walls are often provided on the side of the road, and the side ditching work is also performed near the side walls. Therefore, when a small hydraulic excavator is performing a side ditching operation, if the side wall is detected by an obstacle sensor, the operation of the hydraulic excavator is limited, and the workability of the side ditching operation is reduced. There is a problem of end.

  The present invention has been made in view of the above-described problems of the prior art, and it is possible to prevent the upper swing body from coming into contact with the obstacle while maintaining good workability when performing the side grooving work in the vicinity of the obstacle. The object is to provide a compact hydraulic excavator that can be used.

  In order to solve the above-described problems, the present invention provides a self-propelled lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body, and a left-right swingable front side of the upper revolving body. The present invention is applied to a small hydraulic excavator including a supported swing post and a work front supported by the swing post so as to be able to be lifted and lowered and having a bucket for excavation.

A feature of the configuration adopted by the present invention is that the upper revolving unit has an arc shape in which the rear surface of the counterweight that balances the weight with the work front falls within a virtual circle centered on the turning center of the upper revolving unit. a rear tail swing specifications formed, and an obstacle sensor for detecting the distance to an obstacle existing around the disposed on at least one side face the upper rotating body of the left and right sides of the upper rotating body, A vehicle body controller that determines whether or not the obstacle exists around the upper swing body by the obstacle sensor, and the obstacle sensor extends in the left-right direction through the turning center of the upper swing body. than the virtual line is disposed in front, the vehicle body controller, the working front causes the most swinging the swing post on one side of the lateral direction of the lower traveling body In a state in which turning the upper swing structure to the other side in the lateral direction until they are parallel to the row direction, lateral distance between the position of the obstacle sensor and the other end of the lateral direction of the bucket a reference distance that is set to determine whether the obstacle around the upper rotating body as a threshold is present based on the when the obstacle is determined to exist around the upper rotating body This is to limit the turning motion of the upper turning body .

  According to the present invention, the reference distance obtained by adding a fixed distance to the distance between the end of the bucket and the obstacle sensor in a state where the work front is translated in the left-right direction in order to perform the side grooving work is used as a threshold value. It is possible to determine whether or not there is an obstacle around the upper swing body. Therefore, when a side ditching operation is performed in the vicinity of a side wall or the like, it can be avoided that the side wall or the like is determined as an obstacle around the upper swing body, and the side ditching operation can be performed smoothly. it can. As a result, even when an obstacle exists around the upper swing body, it is possible to maintain good workability when performing the side groove digging work in the vicinity of the obstacle, and the upper swing body contacts the obstacle. Can be suppressed.

1 is a front view showing a hydraulic excavator according to a first embodiment of the present invention. It is a top view which shows a hydraulic shovel. It is a top view which shows the state which the work front translated toward the left side wall of a vehicle body. It is a top view which shows the state which the work front translated toward the right side wall of a vehicle body. It is a top view which shows the state by which the left side wall of the vehicle body was determined to be an obstacle. 1 is a system configuration diagram including a hydraulic system that controls a swing hydraulic motor, a vehicle body controller, an obstacle sensor, and the like. It is a flowchart which shows the control processing which a vehicle body controller performs. It is a top view which shows the hydraulic excavator by 2nd Embodiment in the state which the work front translated toward the right side wall of a vehicle body. It is a top view which shows the state which turned the upper revolving body of a hydraulic shovel 180 degree | times, and the work front translated in parallel toward the left side wall of a vehicle body.

  Hereinafter, a small hydraulic excavator according to the present invention will be described in detail with reference to FIGS.

  1 to 7 show a first embodiment of the present invention. In the figure, a small hydraulic excavator 1 called a mini excavator is used for excavation work in a narrow place such as an urban area, and the machine weight is suppressed to about 1 to 8 tons, for example. The hydraulic excavator 1 includes a self-propelled lower traveling body 2 having left and right crawlers (crawler belts) 2A, and an upper revolving body 4 that is turnably mounted on the lower traveling body 2 via a revolving device 3. Yes. A swing type work front 12, which will be described later, is provided on the front side of the upper swing body 4, and the work front 12 is used for excavating earth and sand. In addition, on the front side of the lower traveling body 2, a soil discharge plate 2B for discharging the excavated earth and sand is provided.

  The upper swing body 4 is a swing frame 5 serving as a base, a counterweight 6 provided on the rear side of the swing frame 5, a driver seat 7 disposed on the front side of the counterweight 6, and an upper side of the driver seat 7. The canopy 8 and the exterior cover 9 provided on the turning frame 5 so as to surround the driver's seat 7 are included.

  Here, as shown in FIG. 2, the upper-part turning body 4 has a width dimension in the left-right direction that is substantially equal to or slightly smaller than the vehicle width of the lower traveling body 2 (the distance between the left and right crawlers 2A). As seen from above, it is formed in a substantially circular shape so as to be within a virtual circle C having a turning radius R defined by the distance from the turning center O to the rear surface 6A of the counterweight 6. As a result, the excavator 1 has a small rear turning specification in which the rear surface 6A of the counterweight 6 is substantially within the vehicle width of the lower traveling body 2 when the upper revolving body 4 performs the turning operation on the lower traveling body 2. It is configured as a hydraulic excavator.

  The revolving frame 5 has a bottom plate 5A and left and right vertical plates 5B standing on the bottom plate 5A, and a cylindrical support bracket 5C extending in the vertical direction is provided on the front end side of each vertical plate 5B. ing. A swing post 10 to be described later is attached to the support bracket 5 </ b> C located on the front side of the revolving frame 5. Here, the upper swing body 4 is formed so as to be substantially within the virtual circle C centered on the swing center O, but the left front corner portion 4A of the upper swing body 4 protrudes outside the virtual circle C. It has become.

  The counterweight 6 is provided so as to extend upward from the rear side of the turning frame 5, and balances the weight with the work front 12. Here, the rear surface 6 </ b> A of the counterweight 6 extends in the left-right direction while being curved in an arc shape so as to be within a virtual circle C centered on the turning center O of the upper turning body 4. The counterweight 6 forms substantially the same surface as the exterior cover 9 and covers the equipment such as the engine from the rear together with the exterior cover 9.

  The driver's seat 7 is disposed on the left side of the upper swing body 4 and is seated by an operator who operates the excavator 1. On the front side of the driver's seat 7, left and right traveling levers / pedals 7 A for controlling the traveling of the lower traveling body 2 are provided. Left and right operation levers 7B (only the left side is shown) are provided for controlling the above. The canopy 8 is configured by a plurality of support columns 8A provided upright on the revolving frame 5 and a roof 8B provided at the upper end of each support column 8A and covering the driver's seat 7 from above.

  The exterior cover 9 includes a left exterior cover 9A that extends from the left end portion of the counterweight 6 to the front side of the revolving frame 5 and a right exterior cover 9B that extends from the right end portion of the counterweight 6 to the front side of the revolving frame 5. Has been. The exterior cover 9 accommodates equipment (not shown) such as an engine, a hydraulic pump, and a heat exchanger mounted on the revolving frame 5.

  The swing post 10 is supported by a support bracket 5C provided on the front side of the revolving frame 5 so as to be swingable in the left-right direction. A bracket 10 </ b> A is provided on the swing post 10, and a swing cylinder 11 is provided between the bracket 10 </ b> A and the turning frame 5. Therefore, by extending and retracting the swing cylinder 11, the swing post 10 is configured to swing (swing) in the left and right directions with respect to the support bracket 5C of the revolving frame 5.

  The work front 12 is supported by the swing post 10 so as to be able to move up and down. The work front 12 includes a boom 12A, an arm 12B attached to the distal end side of the boom 12A, and a bucket 12C attached to the distal end side of the arm 12B. A boom cylinder 12D is provided between the swing post 10 and the boom 12A, an arm cylinder 12E is provided between the boom 12A and the arm 12B, and a bucket cylinder 12F is provided between the arm 12B and the bucket 12C. Is provided.

  Here, as shown in FIG. 3, the swing post 10 is swung rightward and the upper swing body 4 is swung leftward, whereby the work front 12 is moved in the travel direction (front-rear direction) of the lower travel body 2. It is possible to translate to the left side while maintaining a parallel posture. On the other hand, as shown in FIG. 4, the work front 12 is made parallel to the traveling direction of the lower traveling body 2 by swinging the swing post 10 to the left and pivoting the upper swinging body 4 to the right. While maintaining the posture, it can be translated to the right side. In this way, the excavator 1 swings the swing post 10 to one side in the left-right direction and turns the upper swing body 4 to the other side in the left-right direction to translate the work front 12 in the left-right direction. be able to. For this reason, the side groove extending along the road can be excavated by repeating excavation work using the bucket 12C of the work front 12 held in a posture parallel to the traveling direction while traveling the lower traveling body 2. it can.

  The left obstacle sensor 13 is provided on the left side surface 9 </ b> A <b> 1 of the exterior cover 9 that constitutes the upper swing body 4. The left obstacle sensor 13 is constituted by a millimeter wave radar, for example, and detects a distance to an obstacle existing on the left side of the upper swing body 4. In this case, as shown in FIG. 2, the left obstacle sensor 13 is disposed in front of an imaginary line LL extending in the left and right directions through the turning center O of the upper turning body 4.

  Here, in the first embodiment, when it is detected by the left obstacle sensor 13 that an obstacle is present on the left side of the upper swing body 4, a threshold value in which the distance to the obstacle is set in advance. When it is below, it is the structure which restrict | limits the turning action of the upper turning body 4 to the left direction. The threshold value will be described with reference to FIG.

  Since the swing-type hydraulic excavator 1 is suitably used for excavating a gutter on the side of a road such as an urban area, for example, the ditch is dug along the left side wall 101L which is an obstacle standing on the left side of the road. Can be considered. In this case, the swing post 10 is most swung rightward and the upper swing body 4 is swung leftward until the work front 12 is parallel to the travel direction of the lower travel body 2. As a result, the work front 12 can be translated to the leftmost side and brought closest to the left side wall 101L.

  In this state, a reference distance (XL + α) obtained by adding a certain distance α, which is a safety allowance, to the distance XL in the left-right direction between the left end portion 12C1 of the bucket 12C and the left obstacle sensor 13 turns leftward. Is set in advance as a threshold value YL for determining whether or not to limit. Therefore, when the detection distance to the left side wall 101L detected by the left obstacle sensor 13 is larger than the threshold value YL, the left swinging operation of the upper swing body 4 can be freely performed, and when it is equal to or less than the threshold value YL. In the configuration, the left turning operation of the upper turning body 4 is limited.

  The right obstacle sensor 14 is provided on the right side surface 9 </ b> B <b> 1 of the exterior cover 9 that constitutes the upper swing body 4. The right obstacle sensor 14 is also configured by a millimeter wave radar similar to the left obstacle sensor 13 and detects a distance to an obstacle existing on the right side of the upper swing body 4. In this case, the right obstacle sensor 14 is disposed in front of an imaginary line LL extending in the left and right directions through the turning center O of the upper turning body 4.

  Here, in the first embodiment, when the right obstacle sensor 14 detects the presence of an obstacle on the right side of the upper swing body 4, a threshold value in which the distance to the obstacle is set in advance. When it is below, it is the structure which restrict | limits the turning action of the upper turning body 4 to the right direction. This threshold value will be described with reference to FIG.

  The swing-type hydraulic excavator 1 can be considered to dig a ditch along the right side wall 101R that is an obstacle standing on the right side of the road, for example. In this case, the swing post 10 is most swung leftward, and the upper swing body 4 is swung rightward until the work front 12 is parallel to the travel direction of the lower travel body 2. Thereby, the work front 12 can be translated to the rightmost side and can be brought closest to the right side wall 101R.

  In this state, a reference distance (XR + α) obtained by adding a constant distance α, which is a safety allowance, to the distance XR in the left-right direction between the right end portion 12C2 of the bucket 12C and the right obstacle sensor 14 is a rightward turning operation. Is set in advance as a threshold value YR for determining whether or not to limit. Therefore, when the detection distance to the right side wall 101R detected by the right obstacle sensor 14 is larger than the threshold value YR, the right turn operation of the upper swing body 4 can be freely performed and is equal to or less than the threshold value YR. In this case, the right turning operation of the upper turning body 4 is limited.

  Here, the upper turning body 4 is formed in a substantially circular shape so that the width dimension in the left-right direction is set to be substantially equal to the vehicle width of the lower traveling body 2 and fits within the virtual circle C centered on the turning center O. ing. Therefore, when the upper swing body 4 performs the swing operation, the rear side (counterweight 6 side) of the upper swing body 4 with respect to the virtual line LL extending in the left-right direction through the swing center O is lower. The vehicle can turn within the vehicle width of the traveling body 2. Therefore, when the crawler 2A of the lower traveling body 2 is away from the left side wall 101L or the right side wall 101R, the rear side of the upper turning body 4 with respect to the imaginary line LL contacts the left side wall 101L or the right side wall 101R. There is nothing. For this reason, the obstacle detection range by the left and right obstacle sensors 13 and 14 is a fan-shaped area that extends in the front-rear direction around the left and right obstacle sensors 13 and 14. Of these, it is not necessary to detect an obstacle in the latter half of the region corresponding to the rear side of the upper swing body 4. For this reason, in the present embodiment, the obstacle detection ranges by the left and right obstacle sensors 13 and 14 are limited to the first half of the fan-shaped areas with hatching.

  Next, a hydraulic system for controlling the turning operation of the upper turning body 4 will be described with reference to FIG.

  The main hydraulic pump 15 constitutes a hydraulic pressure source together with the tank 16, and the pilot pump 17 constitutes a pilot hydraulic pressure source together with the tank 16. The main hydraulic pump 15 and the pilot pump 17 are driven by an engine 18 as a prime mover. Here, the main hydraulic pump 15 has a capacity variable portion 15A made of, for example, a swash plate, and the capacity variable portion 15A is driven by a regulator 30 described later, whereby the discharge capacity of the main hydraulic pump 15 changes. .

  The swing hydraulic motor 19 constitutes the swing device 3, and is connected to a hydraulic source including the main hydraulic pump 15 and the tank 16 via main pipelines 20 and 21. In the middle of the main pipelines 20 and 21, for example, a hydraulic pilot type directional control valve 22 at 6 port 3 position is provided. The directional control valve 22 has hydraulic pilot portions 22A and 22B. When pilot pressure is not supplied to the hydraulic pilot portions 22A and 22B, the directional control valve 22 maintains a neutral position (a) and is discharged from the main hydraulic pump 15. The pressurized oil is discharged to the tank 16.

  When the pilot pressure is supplied to the hydraulic pilot unit 22A, the direction control valve 22 is switched to the switching position (b), and the pressure oil from the main hydraulic pump 15 is supplied to the swing hydraulic motor 19 via the main line 20. At the same time, the return oil from the swing hydraulic motor 19 is discharged to the tank 16 through the main pipeline 21. Thereby, the turning hydraulic motor 19 rotates, for example, in the left direction, and the upper turning body 4 performs the turning operation in the left direction. On the other hand, when the pilot pressure is supplied to the hydraulic pilot unit 22B, the direction control valve 22 is switched to the switching position (c), and the pressure oil from the main hydraulic pump 15 is supplied to the swing hydraulic motor 19 via the main line 21. At the same time, the return oil from the swing hydraulic motor 19 is discharged to the tank 16 via the main line 20. Thereby, the turning hydraulic motor 19 rotates, for example, in the right direction, and the upper turning body 4 performs the turning operation in the right direction.

  The pilot valve 23 selectively supplies the pilot pressure from the pilot pump 17 to the hydraulic pilot portions 22A and 22B of the direction control valve 22 in accordance with the operation of the operation lever 7B disposed on the side of the driver's seat 7. It is. The pilot pump 17 and the pilot valve 23 are connected via a pilot pipe line 24. The pilot valve 23 and the hydraulic pilot part 22A of the direction control valve 22 are connected via a branch pilot line 24A, and the pilot valve 23 and the hydraulic pilot part 22B of the direction control valve 22 are connected to a branch pilot pipe. They are connected via a path 24B.

  The pressure reducing control valve 25 is provided in the middle of the branch pilot line 24A. The pressure reduction control valve 25 has an electromagnetic pilot section 25A, and a control signal is supplied to the electromagnetic pilot section 25A from a vehicle body controller 27 described later. Then, the pressure reduction control valve 25 performs pressure reduction control on the pilot pressure supplied to the hydraulic pilot part 22 </ b> A of the direction control valve 22 in accordance with a control signal from the vehicle body controller 27. Thereby, the pressure oil supplied to the turning hydraulic motor 19 via the direction control valve 22 is restricted, and the operation speed when the upper turning body 4 turns leftward is restricted.

  The pressure reduction control valve 26 is provided in the middle of the branch pilot line 24B. The pressure reducing control valve 26 has an electromagnetic pilot section 26A, and a control signal is supplied from the vehicle body controller 27 to the electromagnetic pilot section 26A. Then, the pressure reduction control valve 26 controls the pilot pressure supplied to the hydraulic pilot part 22 </ b> B of the direction control valve 22 in accordance with a control signal from the vehicle body controller 27. Thereby, the pressure oil supplied to the turning hydraulic motor 19 via the direction control valve 22 is restricted, and the operation speed when the upper turning body 4 turns rightward is restricted. That is, the turning operation restriction means is constituted by the pressure reducing control valves 25 and 26 and the control signal supplied from the vehicle body controller 27 to the pressure reducing control valves 25 and 26.

  Next, the vehicle body controller 27 that controls the operations of the main hydraulic pump 15, the swing hydraulic motor 19 and the like will be described with reference to FIG.

  The vehicle body controller 27 as an obstacle determination means is mounted on the hydraulic excavator 1 and controls the operation of the turning hydraulic motor 19 and the like based on detection signals from the left and right obstacle sensors 13 and 14. On the input side of the vehicle body controller 27, a left obstacle sensor 13, a right obstacle sensor 14, an engine controller 28, a turning operation restriction switch 29, and the like are connected. On the other hand, to the output side of the vehicle body controller 27, a regulator 30 that drives the displacement variable portion 15 </ b> A of the main hydraulic pump 15, electromagnetic pilot portions 25 </ b> A and 26 </ b> A of pressure reduction control valves 25 and 26, and a vehicle body monitor 31 are connected.

  The engine controller 28 controls, for example, the rotational speed of the engine 18 based on a command signal input from a main controller (not shown). The engine controller 28 outputs a signal corresponding to, for example, the rotational speed of the engine 18 to the vehicle body controller 27. The vehicle body controller 27 outputs a drive signal to the regulator 30 based on a signal from the engine controller 28. Thereby, the regulator 30 drives the displacement variable portion 15A of the main hydraulic pump 15, and the discharge capacity of the main hydraulic pump 15 is controlled according to the rotational speed of the engine 18.

  The turning operation restriction switch 29 is disposed, for example, in the vicinity of the driver's seat 7 and is used by the operator to manually select whether or not to restrict the turning operation of the upper turning body 4. For example, when the turning movement restriction switch 29 is turned on, the vehicle body controller 27 has the distance to the obstacle detected by the left and right obstacle sensors 13 and 14 equal to or less than the threshold YL or YR described above. Sometimes, control for limiting the turning motion of the upper turning body 4 is performed. On the other hand, when the turning movement restriction switch 29 is not turned on (turned off), the vehicle body controller 27 operates the operation lever 7B regardless of the detection results of the left and right obstacle sensors 13 and 14. The control which permits the turning operation | movement of the upper turning body 4 according to this is performed.

  The vehicle body monitor 31 is disposed in the vicinity of the driver's seat 7, for example, and when the distance to the obstacle detected by the left and right obstacle sensors 13 and 14 is equal to or less than the threshold value YL or YR described above, A warning (warning display, warning sound, etc.) is emitted.

  The swing-type hydraulic excavator 1 according to the first embodiment has the above-described configuration. Hereinafter, a case where excavation work is performed near a side wall in an urban area or the like will be described.

  First, an operator seated in the driver's seat 7 starts the engine 18 and operates the traveling lever / pedal 7A to cause the hydraulic excavator 1 to travel. In addition, the operator turns on the turning operation restriction switch 29.

  As a result, as shown in FIG. 5, the hydraulic excavator 1 self-travels to the work site near the left side wall 101 </ b> L by the lower traveling body 2. At this time, the left and right obstacle sensors 13 and 14 each detect a distance to an obstacle existing around the upper swing body 4 and output a signal corresponding to the detected distance to the vehicle body controller 27.

  In this case, as shown in FIG. 5, the left obstacle sensor 13 detects a distance Z to the left side wall 101 </ b> L that is an obstacle, and outputs a signal corresponding to the detected distance Z to the vehicle body controller 27. The vehicle body controller 27 determines whether or not the detection distance Z is less than or equal to the above-described threshold value YL. If the detection distance Z is less than or equal to the threshold value YL, the pilot supplied to the hydraulic pilot unit 22A of the directional control valve 22 is determined. The pressure reduction control by the pressure reduction control valve 25 is performed on the pressure.

  As a result, the pilot pressure supplied to the hydraulic pilot portion 22A of the direction control valve 22 is reduced, and the flow rate of the pressure oil supplied to the swing hydraulic motor 19 is limited. As a result, when the excavator 1 performs excavation work in the vicinity of the left side wall 101L, the operation speed when the upper swing body 4 turns leftward is limited, and the work front 12 contacts the left side wall 101L. Can be avoided, and the work front 12 and the left side wall 101L can be protected.

  On the other hand, when the distance to the obstacle detected by the right obstacle sensor 14 is far away from the upper swing body 4, the vehicle body controller 27 determines that the distance detected by the right obstacle sensor 14 is greater than the threshold YR described above. Therefore, the pilot pressure reduction control by the pressure reduction control valve 26 is not performed. As a result, a pilot pressure corresponding to the operation of the operation lever 7B is supplied to the hydraulic pilot portion 22B of the direction control valve 22. As a result, the operation speed when the upper swing body 4 swings in the right direction is not limited, and the right swing operation of the upper swing body 4 can be freely performed as shown by a two-dot chain line in FIG. Can be done.

  Next, as shown in FIG. 3, when digging a side groove along the left side wall 101 </ b> L, the excavator 1 self-travels to the vicinity of the left side wall 101 </ b> L by the lower traveling body 2, for example, The vehicle stops in a state where the traveling direction and the left side wall 101L are parallel to each other. In this state, the excavator 1 swings the swing post 10 in the right direction and turns the upper swing body 4 in the left direction until the work front 12 becomes parallel to the travel direction of the lower travel body 2. As a result, the work front 12 moves in parallel to the left side and maintains a posture parallel to the left side wall 101L.

  At this time, the left obstacle sensor 13 detects a distance ZL to the left side wall 101L that is an obstacle, and outputs a signal corresponding to the detected distance ZL to the vehicle body controller 27. The vehicle body controller 27 determines whether or not the detection distance ZL is equal to or less than the above-described threshold value YL, and when the detection distance ZL is larger than the threshold value YL, stops the pilot pressure reduction control by the pressure reduction control valve 25 ( Not performed).

  Therefore, even when the excavator 1 is working in the vicinity of the left side wall 101L, when the work front 12 is translated to the left side to perform the side grooving work, the left turning operation of the upper turning body 4 is restricted. It will not be done. As a result, when excavating the side groove along the left side wall 101L, the upper swing body 4 can be turned according to the operation of the operation lever 7B, and the workability of the side groove digging work can be improved.

  On the other hand, as shown in FIG. 4, when excavating a gutter along the right side wall 101R erected on the right side of the road, in the excavator 1, the traveling direction of the lower traveling body 2 and the right side wall 101R are parallel. In this state, the swing post 10 is swung leftward, and the upper swing body 4 is swung rightward until the work front 12 is parallel to the travel direction of the lower travel body 2. As a result, the work front 12 translates to the right side and maintains a posture parallel to the right side wall 101R.

  At this time, the right obstacle sensor 14 detects a distance ZR to the right side wall 101R that is an obstacle, and outputs a signal corresponding to the detected distance ZR to the vehicle body controller 27. The vehicle body controller 27 determines whether or not the detection distance ZR is less than or equal to the above-described threshold value YR, and when the detection distance ZR is greater than the threshold value YR, stops the pilot pressure reduction control by the pressure reduction control valve 26 ( Not performed).

  Therefore, even when the excavator 1 is working near the right side wall 101R, when the work front 12 is translated to the right side and the side groove digging work is performed, the right turn operation of the upper swing body 4 is performed. There is no limit. As a result, when excavating the side groove along the right side wall 101R, the upper swing body 4 can be turned according to the operation of the operation lever 7B, and the workability of the side groove digging work can be improved.

  When the operator turns the turning motion restriction switch 29 to the OFF state, the vehicle body controller 27 does not turn the upper turning body regardless of the distance to the obstacle detected by the left and right obstacle sensors 13 and 14. 4 is allowed to turn left and right. As a result, even when an obstacle exists near the upper swing body 4, the operator operates the operation lever 7B while recognizing the obstacle, so that the upper swing body 4 is moved in the left-right direction according to the operation of the operation lever 7B. Can be swiveled.

  As described above, the vehicle body controller 27 controls the turning operation of the upper-part turning body 4 based on the detection signals from the left and right obstacle sensors 13 and 14, and the control process executed by the vehicle body controller 27 is described below. This will be described with reference to FIG.

  The control process by the vehicle body controller 27 is started when the engine 18 is started, for example. In step 1, it is determined whether or not the turning operation restriction switch 29 is in an ON state. If it is determined as “NO” in step 1, the turning operation of the upper swing body 4 is not limited, so the process proceeds to step 2 to stop the pilot pressure reduction control by the pressure reduction control valves 25 and 26, and The warning by the vehicle body monitor 31 is stopped.

  After step 2 is executed, the process proceeds to step 3 to determine whether or not the engine 18 is stopped. If “YES” is determined in the step 3, the control process is ended, and if “NO” is determined in the step 3, the process returns to the step 1.

  Next, if “YES” is determined in Step 1, the detection distance to the obstacle detected by the left obstacle sensor 13 and the obstacle detected by the right obstacle sensor 14 are determined in Step 4. After reading the detected distance, go to step 5. In step 5, it is determined whether or not the detection distance by the left obstacle sensor 13 is equal to or less than the threshold YL.

  If “YES” is determined in step 5, an obstacle is present in the vicinity of the left side of the upper swing body 4, and therefore, the process proceeds to step 6 and a warning (warning display, warning sound) is displayed by the vehicle body monitor 31. )I do. As a result, the operator can be warned that there is an obstacle in the vicinity of the left side of the upper swing body 4 and can be alerted.

  After step 6 is executed, the process proceeds to step 7 where the pilot pressure for turning left is controlled to be reduced. Specifically, the vehicle body controller 27 outputs a control signal to the electromagnetic pilot part 25A of the pressure reduction control valve 25 to reduce the pilot pressure supplied to the hydraulic pilot part 22A of the direction control valve 22. Thereby, the flow rate of the pressure oil supplied to the turning hydraulic motor 19 through the main pipeline 20 is restricted, and the operation speed when the upper turning body 4 turns leftward is restricted.

  Thus, after the pilot pressure for turning left is controlled to be reduced, the process proceeds to step 8 and the detection distance to the obstacle detected by the left obstacle sensor 13 is read. Then, the process proceeds to step 9, and it is determined whether or not the detection distance by the left obstacle sensor 13 is larger than the threshold YL.

  If “NO” is determined in step 9, the state in which the obstacle exists in the vicinity of the left side of the upper swing body 4 is continued, so the process returns to step 7, and if “YES” is determined in step 9. Since the upper swing body 4 is away from the obstacle, the process proceeds to step 2 and the pilot pressure reduction control by the pressure reduction control valve 25 is stopped and the warning by the vehicle body monitor 31 is stopped.

  On the other hand, if “NO” is determined in the step 5, the process proceeds to a step 10 to determine whether or not the detection distance by the right obstacle sensor 14 is equal to or less than the threshold YR. If “NO” is determined in the step 10, the process returns to the step 4. If “YES” is determined in step 10, the obstacle is present in the vicinity of the right side of the upper swing body 4, and thus the process proceeds to step 11 and a warning (warning display, warning sound) from the vehicle body monitor 31 is reached. )I do. As a result, the operator can be warned that there is an obstacle in the vicinity of the right side of the upper swing body 4 and can be alerted.

  After step 11 is executed, the routine proceeds to step 12, where the pilot pressure for turning right is controlled to be reduced. Specifically, the vehicle body controller 27 outputs a control signal to the electromagnetic pilot part 26A of the pressure reduction control valve 26 to reduce the pilot pressure supplied to the hydraulic pilot part 22B of the direction control valve 22. Thereby, the flow rate of the pressure oil supplied to the turning hydraulic motor 19 through the main pipeline 21 is restricted, and the operation speed when the upper turning body 4 turns rightward is restricted.

  After the pilot pressure for right turn is controlled to be reduced in this way, the process proceeds to step 13, and after reading the detection distance to the obstacle detected by the right obstacle sensor 14, the process proceeds to step 14. In step 14, it is determined whether or not the detection distance by the right obstacle sensor 14 is larger than the threshold YR.

  If it is determined as “NO” in step 14, the state in which the obstacle exists in the vicinity of the right side of the upper swing body 4 is continued, so the process returns to step 12. If it is determined as “YES” in step 14, Since the upper swing body 4 is in a state of being away from the obstacle, the process proceeds to step 2, and the pressure reduction control of the pilot pressure by the pressure reduction control valve 26 is stopped and the warning by the vehicle body monitor 31 is stopped.

  Thus, according to the first embodiment, the left obstacle sensor 13 is provided on the left side surface 9A1 of the left exterior cover 9A constituting the upper swing body 4, and the right obstacle sensor 14 is disposed on the right side surface 9B1 of the right exterior cover 9B. And the vehicle body controller 27 determines whether or not there is an obstacle around the upper swing body 4 based on the distance to the obstacle detected by the left and right obstacle sensors 13 and 14. .

  In this case, when the vehicle body controller 27 translates the work front 12 to the leftmost side, the vehicle body controller 27 adds a fixed distance α to the leftward distance XL between the left end portion 12C1 of the bucket 12C and the left obstacle sensor 13. When the distance (XL + α) is set as a threshold value YL to determine whether there is an obstacle around the upper swing body 4, and when the work front 12 is translated to the rightmost side, the right end 12D1 of the bucket 12C and the right obstacle A reference distance (XR + α) obtained by adding a fixed distance α to the distance XR in the right direction from the sensor 14 is set as a threshold YR to determine whether there is an obstacle around the upper swing body 4.

  As a result, when the excavator 1 performs excavation work, if the distance to the obstacle detected by the left obstacle sensor 13 is smaller than the threshold YL when performing the side ditching work, the upper swing body 4 Left-turning motion can be restricted. Further, when the distance to the obstacle detected by the right obstacle sensor 14 is smaller than the threshold value YR when performing the side ditching operation, the right turning operation of the upper turning body 4 can be restricted. Therefore, it is possible to prevent the work front 12 from coming into contact with the left side wall 101L or the right side wall 101R when the upper turn 4 performs a turning operation, and the work front 12 and the like can be protected.

  On the other hand, for example, when the work front 12 of the excavator 1 is translated to the left side (left side wall 101L side) in the vicinity of the left side wall 101L erected in an urban area, the left obstacle sensor 13 When the detected distance to the obstacle is larger than the threshold YL, the left turning operation of the upper turning body 4 is not limited. Similarly, when the work front 12 of the excavator 1 is translated to the right side (right side wall 101R side) in the vicinity of the right side wall 101R erected in the urban area, the right obstacle sensor 14 When the detected distance to the obstacle is larger than the threshold value YR, the right turning operation of the upper turning body 4 is not restricted. Therefore, when the side groove digging work is performed along the left side wall 101L or the right side wall 101R, the upper swing body 4 can be turned according to the operation of the operation lever 7B, and the workability of the side groove digging work can be improved.

  As a result, in the hydraulic excavator 1 according to the first embodiment, when there is an obstacle around the upper swing body 4, the operation front 12 is made to be an obstacle by restricting the swing operation of the upper swing body 4. When the side groove digging work is performed in the vicinity of the obstacle, it is possible to suppress the turning operation of the upper swing body 4 from being restricted, and to improve the workability of the side groove digging work. Can be kept good.

  In addition, according to the present embodiment, the upper swing body 4 has a rear small turn specification in which the rear surface 6A of the left and right counterweights 6 is formed in an arc shape that fits within a virtual circle C centered on the turn center O. The left and right obstacle sensors 13 and 14 are arranged in front of an imaginary line LL extending in the left-right direction through the turning center O of the upper turning body 4.

  For this reason, when the width dimension in the left-right direction of the upper swing body 4 is set to be substantially equal to the vehicle width of the lower traveling body 2, when the upper swing body 4 performs a turning operation, the upper swing body 4 The rear side (counterweight 6 side) of the imaginary line LL can turn within the vehicle width of the lower traveling body 2. Therefore, when the crawler 2A of the lower traveling body 2 is away from the left and right side walls 101L and 101R, the rear surface 6A of the counterweight 6 is moved to the left and right when the upper revolving body 4 performs the turning operation. The safety of the turning operation can be ensured without contacting the side walls 101L and 101R.

  On the other hand, even when the portion of the upper swing body 4 that is in front of the imaginary line LL passing through the turning center O, for example, the left front corner 4A, protrudes outward from the virtual circle C centered on the turning center O. By arranging the left obstacle sensor 13 in the vicinity of the left front corner 4A, it is possible to avoid the left front corner 4A from contacting the left side wall 101L.

  Further, in the present embodiment, when the vehicle body controller 27 determines that an obstacle exists around the upper swing body 4, pressure reduction control valves 25 and 26 for limiting the swing operation of the upper swing body 4 are provided, and the pressure reduction When it is determined that there is an obstacle on the left side of the upper swing body 4, the control valve 25 restricts the upper swing body 4 from turning leftward, and the pressure reducing control valve 26 is located on the right side of the upper swing body 4. When it is determined that there is an object, the upper turning body 4 is restricted from turning rightward. Thereby, it is possible to avoid the work front 12 from colliding with surrounding obstacles due to the turning operation of the upper turning body 4, and the work front 12 and the like can be protected.

  Next, FIG. 8 and FIG. 9 show a second embodiment of the present invention. The feature of this embodiment is that the left and right side surfaces of the upper swing body are on the side opposite to the driver's seat across the swing post. The obstacle sensor is provided on the side. In the second embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

  Similar to the excavator 1 according to the first embodiment, the excavator 41 according to the second embodiment includes the lower traveling body 2, the upper swing body 42, the swing post 10, and the work front 12. . Here, the upper turning body 42 includes the turning frame 5, the counterweight 6, the driver's seat 7, the canopy 8, and the exterior cover 9, similarly to the upper turning body 4 according to the first embodiment. It is configured.

  The upper turning body 42 has a width dimension in the left-right direction that is substantially equal to the vehicle width of the lower traveling body 2 and is substantially circular when viewed from above so as to be within a virtual circle C centered on the turning center O. Is formed. As a result, the excavator 41 has a small rear turning specification in which the rear surface 6A of the counterweight 6 is substantially within the vehicle width of the lower traveling body 2 when the upper revolving body 42 performs the turning operation on the lower traveling body 2. It is configured as a hydraulic excavator.

  However, the upper turning body 42 is provided with one right obstacle sensor 14 only on the right side surface 9B1 of the right exterior cover 9B among the left exterior cover 9A and the right exterior cover 9B constituting the exterior cover 9. That is, the upper turning body 42 is provided with one right obstacle sensor 14 on the right side surface 9B1 of the right exterior cover 9B located on the opposite side of the driver seat 7 with the swing post 10 interposed therebetween. This is different from the upper swing body 4 according to the first embodiment.

  Here, when excavating a side groove along the right side wall 101 </ b> R erected on the right side of the road using the hydraulic excavator 41, the hydraulic excavator 41 is driven in the traveling direction of the lower traveling body 2 as shown in FIG. 8. In the state where the right side wall 101R and the right side wall 101R are parallel, the swing post 10 is most swung to the opposite side (arrow A1 direction) from the right side wall 101R, and the work front 12 is parallel to the traveling direction of the lower traveling body 2. The upper turning body 42 is turned to the right side wall 101R side (arrow B1 direction) until it becomes. As a result, the work front 12 moves in parallel toward the right side wall 101R and maintains a parallel posture with respect to the right side wall 101R.

  In this state, a reference distance (XR + α) obtained by adding a constant distance α, which is a safety allowance, to the lateral distance XR between the right end portion 12C2 of the bucket 12C and the right obstacle sensor 14 is the right side of the upper swing body 42. It is set as a threshold value YR for determining whether or not the turning motion to the wall 101R side (arrow B1 direction) is restricted. And when the detection distance to the right side wall 101R detected by the right obstacle sensor 14 is larger than the threshold value YR, the turning operation of the upper turning body 42 toward the right side wall 101R (arrow B1 direction) is freely performed. If it is less than the threshold value YR, the turning operation of the upper turning body 42 toward the right side wall 101R (arrow B1 direction) is limited.

  On the other hand, when digging a gutter along the left side wall 101L erected on the left side of the road, the excavator 41 turns the upper turning body 42 by 180 degrees as shown in FIG. Thereby, the rear side (counterweight 6 side) of the upper swing body 42 corresponds to the front side (the earth discharging plate 2B side) of the lower traveling body 2, and the left obstacle 101 can be detected by the right obstacle sensor 14. .

  In this state, the swing post 10 is most swung to the opposite side (arrow A2 direction) from the left side wall 101L, and the upper swing body 42 is moved to the left side until the work front 12 is parallel to the traveling direction of the lower traveling body 2. Turn to the wall 101L side (arrow B2 direction). Thereby, the work front 12 can be most translated in the direction approaching the left side wall 101L, and can be brought closest to the left side wall 101L.

  In this state, a reference distance (XL + α) obtained by adding a constant distance α, which is a safety allowance, to the lateral distance XL between the right end portion 12C2 of the bucket 12C and the right obstacle sensor 14 is the left side of the upper swing body 42. It is set as a threshold value YL for determining whether or not to limit the turning operation toward the wall 101L (arrow B2 direction). And when the detection distance to the left side wall 101L detected by the right obstacle sensor 14 is larger than the threshold YL, the turning operation of the upper turning body 42 to the left side wall 101L side (arrow B2 direction) is freely performed. When it is less than or equal to the threshold value YL, the turning operation of the upper turning body 42 toward the left side wall 101L (arrow B2 direction) is limited.

  The hydraulic excavator 41 according to the second embodiment has the above-described configuration, and there is no particular difference in basic operation from the hydraulic excavator 1 according to the first embodiment.

  However, in the hydraulic excavator 41 according to the second embodiment, the right side surface 9B1 of the right exterior cover 9B that is the side surface opposite to the driver's seat 7 across the swing post 10 among the left and right side surfaces of the upper swing body 42. Further, only one right obstacle sensor 14 is provided. And it is set as the structure which detects the left side wall 101L and the right side wall 101R using the one right obstacle sensor 14 by turning the upper turning body 42 180 degree | times with respect to the lower traveling body 2. FIG.

  Thus, unlike the first embodiment, it is not necessary to provide two obstacle sensors, the left obstacle sensor 13 and the right obstacle sensor 14, and by reducing the number of expensive obstacle sensors. The manufacturing cost of the hydraulic excavator 41 can be reduced.

  In this case, the visibility of the operator sitting on the driver's seat 7 on the side opposite to the driver's seat 7 with the swing post 10 interposed therebetween decreases. In contrast, in the second embodiment, the right obstacle sensor 14 is provided on the right side surface of the upper swing body 42 (the right side surface 9B1 of the right exterior cover 9B). As a result, the right obstacle sensor 14 can reliably detect an obstacle in a region that is difficult for the operator seated in the driver's seat 7 to see.

  In the embodiment, a case where millimeter wave radar is used as the left and right left obstacle sensors 13 and 14 is illustrated. However, the present invention is not limited to this, and an obstacle sensor may be configured using, for example, an ultrasonic sensor or a laser radar.

  Moreover, in embodiment, the hydraulic shovel 1 (41) provided with the canopy 8 which covers the driver's seat 7 from upper direction is illustrated. However, the present invention is not limited to this, and can be applied to, for example, a hydraulic excavator provided with a cab that surrounds the driver's seat 7.

2 Lower traveling body 4, 42 Upper revolving body 6 Counterweight 6A Rear 7 Driver's seat 9A Left exterior cover 9A1 Left side 9B Right exterior cover 9B1 Right side 10 Swing post 12 Work front 12C Bucket 12C1 Left end 12C2 Right end 13 Left obstacle Sensor 14 Right obstacle sensor 15 Main hydraulic pump 17 Pilot pump 18 Engine (motor)
DESCRIPTION OF SYMBOLS 19 Turning hydraulic motor 20,21 Main pipe line 22 Directional control valve 22A, 22B Hydraulic pilot part 23 Pilot valve 24 Pilot pipe line 25,26 Pressure-reduction control valve (turning operation restriction means)
27 Body controller (obstacle determination means)

Claims (5)

A self-propelled lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body, a swing post that is supported swingably in the left-right direction on the front side of the upper revolving body, and the swing post In a small hydraulic excavator comprising a working front having a bucket for excavation supported so as to be able to move up and down,
The upper swivel body is a small rear swivel specification formed in an arc shape in which a rear surface of a counterweight that balances the weight with the work front fits within a virtual circle centered on the swivel center of the upper swivel body,
An obstacle sensor that is disposed on at least one of the left and right side surfaces of the upper swing body and detects a distance to an obstacle existing around the upper swing body;
A vehicle body controller that determines whether or not the obstacle exists around the upper swing body by the obstacle sensor;
The obstacle sensor is disposed in front of an imaginary line extending in the left-right direction through the turning center of the upper turning body,
The vehicle body controller, to pivot the upper rotating body on the other side in the lateral direction to the working front causes most swing the front Symbol swing post on one side in the lateral direction is parallel to the running direction of the lower traveling body in the state, the surrounding of the upper rotating body as a threshold reference distance set based on lateral distance between the position of the obstacle sensor and the other end of the lateral direction of the bucket A small-sized hydraulic excavator characterized by determining whether or not an obstacle is present and restricting the turning motion of the upper swing body when it is determined that the obstacle exists around the upper swing body . A driver's seat is provided on one side in the left-right direction of the upper swing body,
The small-sized hydraulic excavator according to claim 1, wherein the obstacle sensor is provided on a side surface opposite to the driver's seat across the swing post. The vehicle body controller, when it is determined that an obstacle exists on one side in the lateral direction of the front SL upper revolving structure, and limits the upper swing structure is pivoted to one side in the horizontal direction, the other side in the lateral direction The small-sized hydraulic excavator according to claim 1, wherein the excavator is allowed to turn to the right. A main hydraulic pump that discharges pressure oil by being driven by a prime mover;
A pilot pump that discharges pilot pressure oil by being driven by the prime mover;
A turning hydraulic motor for turning the upper turning body by being supplied with pressure oil from the main hydraulic pump;
Direction of pressure oil supplied to the swing hydraulic motor according to a pilot pressure provided in the middle of a main pipeline connecting the main hydraulic pump and the swing hydraulic motor to the hydraulic pilot section from the pilot pump A directional control valve to control the
A pilot valve for controlling a pilot pressure supplied from the pilot pump to the hydraulic pilot portion of the directional control valve;
A pressure reduction control valve provided in the middle of a pilot line connecting the hydraulic pilot portion of the directional control valve and the pilot valve;
The vehicle body controller, a compact hydraulic excavator according to claim 1, characterized in that to limit the swivel motion to limit the operating speed of the hydraulic swing motor by controlling the pre-Symbol pressure reduction control valve. The obstacle detection range by the obstacle sensor is set to the front half of the fan-shaped area that extends in the front-rear direction of the upper swing body around the obstacle sensor that is the detection range of the obstacle sensor. The small-sized hydraulic excavator according to claim 1, wherein:

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