JP2016185864A - Work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work vehicle which can suppress a tip of a boom from entering a work limit region without stopping suddenly turning of a turning body and tilting of the boom performed at the same time.SOLUTION: The work vehicle performs: turning/tilting processes for making a turning motor turn a turning body and making a derricking cylinder tilt a boom; a first determining process that determines a limit line showing a boundary between an allowable work region and a work limit region; and a second determining process that determines a regulating region which regulates the turning/tilting processes from the limit line toward the allowable work region, which slowly stops the turning motor so that a tip of the boom stops at a turning limit line (S33) in response to intersection of an extension line of a movement track of the tip of the boom moved at the turning/tilting process with a first outline of the regulating region (S32: the first outline), and slowly stops the derricking cylinder so that the tip of the boom stops at a second tilting limit line (S34) in response to intersection of the extension line of the movement track with a second outline of the regulating region (S32; the second outline).SELECTED DRAWING: Figure 4

Description

  The present invention relates to a work vehicle capable of simultaneously turning a turning body and raising and lowering a boom.

  2. Description of the Related Art Conventionally, a crane vehicle is known that includes a lower traveling body, an upper revolving body that is supported by the lower traveling body so as to be able to swivel, and a boom that is supported by the upper revolving body so as to be raised and lowered (for example, Patent Document 1). 2). Further, in the crane vehicles described in Patent Documents 1 and 2, for example, in order to prevent the crane vehicle from overturning or to prevent contact with an obstacle, a work limit region and a turning slow stop region are set. Yes.

  The work limit area is an area where entry of the tip of the boom is prohibited. The turning slow stop area is an area where the turning speed of the upper turning body is gradually reduced so that the tip of the boom does not enter the work limit area. Then, the crane vehicle gradually reduces the turning speed so that the turning of the upper turning body stops before the work limit area when the tip of the boom enters the turning slow stop area during the turning of the upper turning body ( Hereinafter referred to as “slow stop”).

JP 11-139771 A Japanese Patent No. 3252007

  However, the above-described slow stop control is based on the premise that the upper swing body is turned independently. Therefore, when the turning of the upper revolving structure and the fall of the boom are performed at the same time, the turn or the fall may have to be stopped suddenly. As a result, the suspended load may swing greatly or the boom may be damaged.

  The present invention has been made in view of the above circumstances, and the purpose of the present invention is to make the tip of the boom without suddenly stopping the turning and overturning even when the turning of the turning body and the overturning of the boom are performed simultaneously. An object of the present invention is to provide a work vehicle that can prevent the vehicle from entering the work limit region.

  (1) A work vehicle according to the present invention includes a traveling body, a revolving body supported by the traveling body so as to be able to swivel, a boom supported by the revolving body so as to be raised and lowered, and a turning actuator for turning the revolving body. And a hoisting actuator for raising and lowering the boom, a first operation unit for accepting an operation for instructing the turning of the revolving body, a second operation unit for accepting an operation for instructing an overturn of the boom, and a control unit. The control unit is a turning / falling process for turning the turning body to the turning actuator and causing the hoisting actuator to fall the boom in response to simultaneous operation of the first operation unit and the second operation unit. And a first determination process for determining a limit line indicating a boundary between a workable area where entry of the tip of the boom is allowed and a work limit area where entry is prohibited, and the workline area side from the limit line A second determination process for determining a restriction area for restricting the turning and overturning process; and at least one of the turning actuator and the raising and lowering actuator in response to the tip of the boom entering the restriction area by the turning and falling process. A slow stop process for performing a slow stop is executed. In the first determination process, the control unit is the limit line that indicates a boundary of the work limit region where entry of the tip of the boom that has been laid down is prohibited, and has an arc shape with a first radius. Prohibition of entry of the first falling limit line, the second falling limit line adjacent to the first falling limit line in the turning direction and having a second radius smaller than the first radius, and the tip of the boom by turning the turning body The limit line indicating the boundary of the work limit area to be determined, the turning limit line connecting the adjacent ends of the first and second lodging limit lines, and the second In the determination process, an intersection of the second lodging limit line and the turning limit line is set as one vertex, an extension line of a predetermined length of the second lodging limit line is set as a first contour line, and the turning limit line An extension line of a predetermined length is used as the second contour line. The shape area is determined as the restriction area, and in the slow stop process, the extension line of the movement locus of the tip of the boom moved by the turning / falling process intersects the first contour line, The swing actuator is gently stopped so that the tip of the boom stops at the turning limit line, and the extension of the movement trajectory intersects the second contour line, so that the tip of the boom is in the second collapsed position. The undulation actuator is gently stopped to stop at the limit line.

  According to the above configuration, one of the turning actuator and the hoisting actuator is gently stopped according to the positional relationship between the extension line of the movement locus at the tip of the boom and the restriction region. And since the above-mentioned judgment is performed at the timing when the front-end | tip of a boom entered into the control area, the distance required for the slow stop of an actuator can be ensured. As a result, it is possible to prevent the tip of the boom from entering the work limit area without suddenly stopping turning and overturning.

  (2) Preferably, in the slow stop process, the control unit is configured so that the tip of the boom stops at the intersection in response to an extension line of the movement trajectory passing through the intersection. And the undulation actuator is gently stopped.

  According to the said structure, it can suppress that the front-end | tip of a boom passes into the work limit area | region through the intersection of a 2nd lodging limit line and a turning limit line.

  (3) Preferably, in the second determination process, the control unit lengthens the first contour line as the turning speed of the revolving body increases, and increases the second contour line as the lowering speed of the boom. Lengthen.

  According to the above configuration, it is possible to secure a distance necessary for safely and gently stopping the turning of the turning body and the falling of the boom.

  (4) As an example, in the first determination process, the control unit extends side by side with the first fall limit line on the workable area side from the first fall limit line, and slowly stops the boom fall. A first lodging / slow stop line indicating the boundary of the lodging / slowing stop region, and a second indicating the boundary of the lodging / slowing stop region extending along the second lodging limit line on the workable region side from the second lodging limit line. A two-folding slow stop line and a turning slow stop line extending along the turning limit line on the workable area side from the turning limit line and indicating a boundary of the turning slow stop area for gently stopping the turning of the turning body. decide. And in the said 2nd determination process, the said control part WHEREIN: The 3rd outline which is an extension line of predetermined length of the said 1st outline, the said 2nd outline, and the said 2nd lodging slow stop line, The graphic area surrounded by the fourth contour line, which is an extension line of a predetermined length of the turning slow stop line, is determined as the restriction area.

  (5) As another example, the control unit, in the second determination process, has an arc-shaped third contour having a third radius centered on the first contour line, the second contour line, and the intersection. The graphic area surrounded by the line is determined as the restriction area.

  According to the present invention, at the timing when the tip of the boom enters the restriction region, at least one of the turning actuator and the undulation actuator is gently stopped according to the positional relationship between the extension line of the movement locus of the boom tip and the restriction region. Therefore, it is possible to prevent the tip of the boom from entering the work limit area without suddenly stopping the turning and overturning.

FIG. 1 is a schematic view of a rough terrain crane 10 according to the present embodiment. FIG. 2 is a functional block diagram of the rough terrain crane 10. FIG. 3 is a flowchart of the operation control process. FIG. 4 is a flowchart of the slow stop process. FIG. 5 is a diagram illustrating examples of the limit lines 61 to 64 and the slow stop lines 66 to 69. FIG. 6 is a diagram illustrating an example of the restriction region in the present embodiment. FIG. 7 is a diagram showing the relationship between the extension lines 71 ′ to 73 ′ of the movement trajectories 71 to 73 at the tip of the telescopic boom 32 and the restriction regions.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. In addition, this embodiment is only 1 aspect of this invention, and it cannot be overemphasized that an embodiment may be changed in the range which does not change the summary of this invention.

[Rough terrain crane 10]
As shown in FIG. 1, the rough terrain crane 10 according to the present embodiment mainly includes a lower traveling body 20 and an upper swing body 30. The rough terrain crane 10 is an example of a work vehicle. However, a specific example of the work vehicle is not limited to the rough terrain crane 10, and may be, for example, an all terrain crane, a cargo crane, an aerial work vehicle, or the like.

[Lower traveling body 20]
The lower traveling body 20 has a pair of left and right front wheels 21 and a pair of left and right rear wheels 22 (only the right side is shown in FIG. 1). The front wheels 21 and the rear wheels 22 are rotated by the driving force of an engine (not shown) transmitted via a transmission (not shown). The lower traveling body 20 travels when a steering wheel, an accelerator pedal, a brake pedal, and the like installed in a cabin 34 described later are operated by an operator.

  Further, the lower traveling body 20 has a pair of left and right outriggers 23 provided on the front side of the lower traveling body 20 and a pair of left and right outriggers 24 provided on the rear side of the lower traveling body 20 (in FIG. 1, Only the right side is shown). The outriggers 23 and 24 can change state between an overhanging state in which the outriggers 23 and 24 are grounded to the ground at a position protruding in the left-right direction and a retracted state in which the outriggers 23 and 24 are stored in the lower traveling body 20 while being separated from the ground. is there.

  By setting the outriggers 23 and 24 to the extended state during the operation of the upper swing body 30, the posture of the rough terrain crane 10 is stabilized. On the other hand, the outriggers 23 and 24 are placed in a retracted state when the lower traveling body 20 travels. In addition, the rough terrain crane 10 can vary the amount of extension of the outriggers 23 and 24 on the left and right. In the example of FIG. 5, the overhang amounts of the right outriggers 23, 24 are smaller than the overhang amounts of the left outriggers 23, 24.

[Upper turning body 30]
The upper turning body 30 is supported by the lower traveling body 20 through a turning bearing (not shown) so as to be turnable. The upper turning body 30 is turned by a turning motor 31 (see FIG. 2). The turning motor 31 is an example of a turning actuator. Further, as shown in FIG. 1, the upper swing body 30 mainly includes a telescopic boom 32, a hook 33, and a cabin 34.

  The telescopic boom 32 is supported by the upper swing body 30 so as to be able to undulate and extend. The telescopic boom 32 is raised and lowered by the hoisting cylinder 35 and is extended and retracted by the telescopic cylinder 36 (see FIG. 2). The telescopic boom 32 is not limited to a box-type boom, and may be a lattice-type jib. The hoisting cylinder 35 is an example of a hoisting actuator. The hook 33 is suspended from a rope 38 that extends downward from the distal end of the telescopic boom 32. The hook 33 is raised and lowered by winding and unwinding the rope 38 by the winch 39 (see FIG. 2). Further, the cabin 34 includes an operation unit 56 (see FIG. 2) for operating the lower traveling body 20 and the upper swing body 30.

[Control unit 50]
As shown in FIG. 2, the rough telelane crane 10 includes a control unit 50. The control unit 50 controls the operation of the rough terrain crane 10. The control unit 50 may be realized by a CPU (Central Processing Unit) that executes a program stored in a memory, may be realized by a hardware circuit, or may be a combination thereof.

  As shown in FIG. 2, the control unit 50 acquires various signals output from the turning angle sensor 51, the undulation angle sensor 52, the boom length sensor 53, the suspension load sensor 54, the outrigger sensor 55, and the operation unit 56. To do. Further, the control unit 50 controls the turning motor 31, the hoisting cylinder 35, the telescopic cylinder 36, the winch 39, and the outriggers 23 and 24 based on the acquired various signals.

  The turning angle sensor 51 outputs a detection signal corresponding to the turning angle of the upper turning body 30 (for example, the angle in the clockwise direction with the forward direction of the lower traveling body 20 being 0 °). The hoisting angle sensor 52 outputs a detection signal corresponding to the hoisting angle of the telescopic boom 32 (the angle formed by the horizontal direction and the telescopic boom 32). The boom length sensor 53 outputs a detection signal corresponding to the length of the telescopic boom 32. The suspended load sensor 54 outputs a detection signal corresponding to the weight of the suspended load 40 suspended from the hook 33. The outrigger sensor 55 outputs a detection signal corresponding to the state of the outriggers 23 and 24 and the overhang amount.

  The operation unit 56 receives a user operation for operating the rough terrain crane 10. And the operation part 56 outputs the operation signal according to the received user operation. That is, the control unit 50 causes the lower traveling body 20 to travel based on the user operation received through the operation unit 56 and causes the upper swing body 30 to operate. The operation unit 56 includes a lever for operating the rough terrain crane 10, a steering, a pedal, an operation panel, and the like.

  The operation unit 56 according to the present embodiment includes a turning lever that drives the turning motor 31 and a hoisting lever that drives the hoisting cylinder 35. The user can turn the upper turning body 30 by operating the turning lever, and can raise and lower the telescopic boom 32 by operating the raising and lowering lever. The turning lever is an example of a first operation unit that receives an operation for instructing turning of the upper turning body 30. The raising / lowering lever is an example of a second operation unit that receives an operation for instructing the fall of the telescopic boom 32.

  For example, the control unit 50 specifies the turning direction according to the falling direction of the turning lever, and specifies the turning speed according to the amount of fall of the turning lever. Then, the control unit 50 drives the turning motor 31 so that the upper turning body 30 is turned at the turning speed specified in the specified turning direction. For example, the control unit 50 identifies the undulation direction (rise or fall) according to the lie direction of the undulation lever, and identifies the undulation speed according to the amount of the undulation lever. Then, the controller 50 drives the hoisting cylinder 35 so that the telescopic boom 32 is hoisted at the hoisting speed specified in the specified hoisting direction. In addition, a turning motor or a raising / lowering cylinder may be driven in accordance with the operation of each of the above-described turning, raising / lowering, and falling / lowering operation levers, and the speed may be specified by the amount of change in each angle.

  Further, the turning motor 31, the hoisting cylinder 35, the telescopic cylinder 36, and the winch 39 according to the present embodiment are hydraulic actuators. That is, the control unit 50 drives each actuator by controlling the direction and flow rate of the hydraulic oil to be supplied. However, the actuator of the present invention is not limited to a hydraulic type, and may be an electric type or the like.

[Operation of rough terrain crane 10]
Next, the operation of the rough terrain crane 10 will be described with reference to FIGS. For example, the control unit 50 starts the operation control process shown in FIG. 3 in response to the operation signal output from both the turning lever and the raising / lowering lever. The user can operate both the turning lever and the raising / lowering lever at the same time (hereinafter referred to as “combined operation”). In the present specification, processing when only one of the turning lever and the raising / lowering lever is operated alone (hereinafter referred to as “single operation”) is omitted. Further, in the present specification, the process of raising and lowering the telescopic boom 32 and the process of extending and retracting the telescopic boom 32 are omitted.

  First, the control unit 50 executes a first determination process (S11). The first determination process is a process of determining a limit line indicating the boundary between the workable area and the work limit area and a slow stop line indicating the boundary of the slow stop area. The workable area is an area where the tip of the telescopic boom 32 is allowed to enter. The work limit area is an area where entry of the tip of the telescopic boom 32 is prohibited. The slow stop region is a region where the operation of the upper swing body 30 or the telescopic boom 32 is gently stopped. A workable area, a work limit area, a slow stop area, and a restriction area described later are virtual areas on a horizontal plane including the rough terrain crane 10.

  The limit lines include lodging limit lines 61 and 62 and turning limit lines 63 and 64, as shown in FIG. The fall limit lines 61 and 62 indicate the boundaries of the work limit area where entry of the fallen telescopic boom 32 is prohibited. The turning limit lines 63 and 64 indicate the boundaries of the work limit region where the intrusion of the telescopic boom 32 due to the turning of the upper turning body 30 is prohibited. Further, the slow stop lines include the overturning slow stop lines 66 and 67 and the turning slow stop lines 68 and 69. The fall / slow stop lines 66 and 67 indicate boundaries of a fall / slow stop region where the fall of the telescopic boom 32 is gently stopped. The turning gentle stop lines 68 and 69 indicate the boundaries of the turning slow stop region where the turning of the upper turning body 30 is slowly stopped. The limit line and the slow stop line are virtual lines on the horizontal plane including the rough terrain crane 10.

The control unit 50 determines the lodging limit lines 61 and 62 based on, for example, the overhang amounts of the outriggers 23 and 24 and the weight of the suspended load 40. The lodging limit line 61 has a circular arc shape with a radius R ₁ centering on the turning center of the upper turning body 30. The lodging limit line 62 has an arc shape with a radius R ₂ (<R ₁ ) centered on the turning center of the upper turning body 30. In addition, the lodging limit lines 61 and 62 are adjacent to each other in the turning direction of the upper turning body 30. The lodging limit line 61 is an example of the first lodging limit line, the lodging limit line 62 is an example of the second lodging limit line, the radius R ₁ is an example of the first radius, and the radius R ₂ is the second radius of the second radius. It is an example.

In the example of FIG. 5, the control unit 50 arranges the lodging limit line 61 on the front, left, and rear sides of the rough terrain crane 10, and the A lodging limit line 62 is arranged in the direction. The control unit 50 includes, for example, set to a small enough radius _R 1, _{R 2} overhang of the outriggers 23 and 24 is small, setting a small radius _R 1, _{R 2} as the weight of the suspended load 40 is large.

  Next, the control unit 50 determines the turning limit lines 63 and 64 that connect the end points adjacent to each other of the lodging limit lines 61 and 62. In the example of FIG. 5, the turning limit line 63 is a part of a straight line that passes through the turning center of the upper turning body 30 and extends diagonally right forward of the rough terrain crane 10. Further, the turning limit line 64 is a part of a straight line that passes through the turning center of the upper turning body 30 and extends obliquely rearward to the right of the rough terrain crane 10.

Next, the control unit 50 determines the fall / slow stop lines 66 and 67 based on the fall speed of the telescopic boom 32, for example. The lodging slow stop lines 66 and 67 extend alongside the lodging limit lines 61 and 62 on the workable area side of the lodging limit lines 61 and 62. In the example of FIG. 5, the overturning slow stop line 66 has an arc shape with a radius R ₃ (<R ₁ ) centered on the turning center of the upper turning body 30. The overturning slow stop line 67 has an arc shape with a radius R ₄ (<R ₂ ) centered on the turning center of the upper turning body 30.

  “Two lines extending side by side” means that the distance between the two lines hardly changes depending on the location. Typically, if two lines are straight, they are “parallel” and if two lines are arcs, they are concentric arcs, but they need not be strictly parallel or concentric arcs. That is, as shown in FIG. 5, it means that the lodging limit lines 61 and 62 and the lodging slow stop lines 66 and 67 do not intersect with each other and extend in substantially the same direction. The relationship between turning limit lines 63 and 64, which will be described later, and turning slow stop lines 68 and 69 is the same.

Next, the control unit 50 determines the turning slow stop lines 68 and 69 based on, for example, the turning speed of the upper turning body 30. The turning slow stop lines 68 and 69 extend alongside the turning limit lines 63 and 64 on the workable region side of the turning limit lines 63 and 64. In the example of FIG. 5, the turning slow stop line 68 is a straight line that passes through the turning center of the upper turning body 30 and is inclined counterclockwise by the inclination angle θ ₁ from the turning limit line 63. The turning slow stop line 69 is a straight line that passes through the turning center of the upper turning body 30 and is inclined clockwise by the inclination angle θ ₂ from the turning limit line 64.

The control unit 50, as laid down speed of the telescopic boom 32 is high, to reduce the radius _R 3, _{R 4.} Alternatively, the control unit 50 may determine the radii R ₃ and R ₄ based on the maximum lodging speed of the telescopic boom 32. Similarly, the control unit 50 increases the inclination angles θ ₁ and θ ₂ as the turning speed of the upper turning body 30 increases. Alternatively, the control unit 50 may determine the inclination angles θ ₁ and θ ₂ based on the maximum turning speed of the upper turning body 30.

  As a result, the region surrounded by the lodging limit lines 61 and 62 and the turning limit lines 63 and 64 becomes the workable region. Moreover, the area | region outside the lodging limit lines 61 and 62 and the turning limit lines 63 and 64 becomes a work limit area. Further, the area surrounded by the lodging limit line 61, the lodging slow stop line 66, and the turning limit lines 63, 64, and the extension line of the lodging limit line 62, the lodging gentle stop line 67, and the turning limit lines 63, 64 are surrounded. This area becomes the lodging and slow stop area. Further, a region surrounded by an extension line of the turning limit line 63, the turning slow stop line 68, the lodging limit line 61, and the lodging limit line 62, the turning limit line 64, the turning slow stop line 69, the lodging limit line 61, and A region surrounded by an extension line of the lodging limit line 62 is a turning slow stop region.

  According to the first determination process described above, the overturning slow stop region or the turning slow stop region is provided between the workable region and the work limit region. As a result, turning of the upper turning body 30 and falling of the telescopic boom 32 can be safely and slowly stopped. However, at the positions of intersections A and B of the lodging limit line 62 and the turning limit line 63, the turnable area and the work limit area are in contact with each other. That is, when the tip of the telescopic boom 32 passes near the intersections A and B by the combined operation, there is a possibility that the turning of the upper swing body 30 and the collapse of the telescopic boom 32 are suddenly stopped.

  Therefore, the control unit 50 executes a second determination process (S12). The second determination process is a process for determining the restriction area. The restriction area is an area for restricting simultaneous execution of the process of turning the upper-part turning body 30 and the process of causing the telescopic boom 32 to fall down. The restriction region is, for example, a region different from the overturning slow stop region and the turning slow stop region in the workable region. The restriction region according to the present embodiment is a region circumscribing the overturning slow stop region and the turning slow stop region. However, a part of the regulation region may overlap with the overturning slow stop region or the turning slow stop region.

  The restriction region in the present embodiment is a region formed around the intersection A of the lodging limit line 62 and the turning limit line 63. More specifically, as shown in FIG. 6, the restriction region in the present embodiment has an intersection A as one of the vertices, and an extension line of a predetermined length of the lodging limit line 62 as a first contour line 62 ′. In addition, it refers to a graphic area having an extension line of a predetermined length of the turning limit line 63 as a second contour line 63 ′. Similarly, a restriction region is also formed around the intersection B of the lodging limit line 62 and the turning limit line 64.

  As an example, as shown in FIG. 6A, the control unit 50 includes a first contour line 62 ′ that is an extension of a predetermined length of the lodging limit line 62 and a predetermined length of the turning limit line 63. A second contour line 63 ′ which is an extension line of the above, a third contour line 67 ′ which is an extension line of a predetermined length of the overturning gentle stop line 67, and an extension line of a predetermined length of the turning slow stop line 68. A graphic area surrounded by a certain fourth contour line 68 ′ may be determined as a restriction area.

As described above, the inclination angle theta ₁ of the turning slow stop line 68 increases with increasing turning speed, the first contour line 62 ', the turning speed becomes higher the longer faster. In other words, the size of the turning direction of the restriction region increases as the turning speed increases. Further, as described above, the radius R ₄ of the lodging slow stop line 67 becomes smaller as the lodging speed increases, so the second contour line 63 ′ becomes longer as the lodging speed increases. In other words, the size of the restriction area in the turning radius direction increases as the lodging speed increases.

As another example, as illustrated in FIG. 6B, the control unit 50 includes a first contour line 62 ′ that is an extension of a predetermined length of the lodging limit line 62 and a predetermined limit of the turning limit line 63. A graphic region surrounded by the second contour line 63 ′, which is an extension of the length, and the arc-shaped third contour line 70 having a radius R ₅ centered on the intersection A may be determined as the restriction region. . Control unit 50, as laid down speed is higher, and / or, as the rotation speed is high, may be increased radius R _5. That is, the first contour line 62 ′ and the second contour line 63 ′ of the restriction region shown in FIG. 6B become longer as the lodging speed is higher and / or as the turning speed is faster. Radius R ₅ is an example of a third radius.

  Next, the control unit 50 drives the turning motor 31 and the hoisting cylinder 35 (S13). Specifically, the control unit 50 supplies the hydraulic oil having a flow rate corresponding to the amount of fall of the turning lever to the turning motor 31 in a direction corresponding to the falling direction of the turning lever to turn the upper turning body 30. In addition, the control unit 50 supplies the hydraulic oil at a flow rate corresponding to the amount of collapse of the hoisting lever to the hoisting cylinder 35 in the direction corresponding to the tilting direction of the hoisting lever, and causes the telescopic boom 32 to fall. The process of step S13 is an example of a turning lodging process.

  The control unit 50 continues the turning and lodging process until the operation of the operation unit 56 is finished (S14: No). Although illustration is omitted, the control unit 50 re-executes steps S11 and S12 in response to changes in the operation amounts of the turning lever and the hoisting lever or in response to changes in the weight of the suspended load 40. May be. On the other hand, the control unit 50 stops the swing motor 31 and the hoisting cylinder 35 in response to the operation unit 56 not being operated (S14: Yes), and ends the operation control process.

  Further, the control unit 50 monitors the position of the tip of the telescopic boom 32 that is moved by the turning-over process (S15, S16). The control unit 50 is, for example, a well-known method based on the turning angle acquired from the turning angle sensor 51, the undulation angle acquired from the undulation angle sensor 52, and the length of the telescopic boom 32 acquired from the boom length sensor 53. Thus, the position of the tip of the telescopic boom 32 can be specified. Then, the control unit 50 continues the turning and falling process in response to the tip of the telescopic boom 32 being within the workable area (S15: Yes) (S13).

  Further, the control unit 50 gently stops the turning motor 31 in response to the tip of the telescopic boom 32 being in the turning slow stop region (S15: No & S16: turning slow stop region) (S17). The control unit 50 gradually reduces the turning speed of the upper turning body 30 so that the tip of the telescopic boom 32 stops on the turning limit lines 63 and 64. More specifically, the control unit 50 gradually reduces the amount of hydraulic oil supplied to the turning motor 31. That is, when the tip of the telescopic boom 32 is located within the turning slow stop region, the control unit 50 does not drive the turning motor 31 in response to the operation of the turning lever.

  Further, the control unit 50 gently stops the hoisting cylinder 35 in response to the tip of the telescopic boom 32 being in the overturning slow stop region (S15: No & S16: overturning slow stop region) (S18). The controller 50 gradually decelerates the lodging speed of the telescopic boom 32 so that the tip of the telescopic boom 32 stops on the lodging limit lines 61 and 62. More specifically, the control unit 50 gradually reduces the amount of hydraulic oil supplied to the undulation cylinder 35. That is, when the tip of the telescopic boom 32 is located in the overturning slow stop region, the control unit 50 does not drive the hoisting cylinder 35 according to the operation of the hoisting lever.

  In step S17, the control unit 50 sets the turning speed of the turning motor 31 in a speed pattern in which the suspended load 40 does not swing in the turning direction when the tip of the telescopic boom 32 stops on the turning limit lines 63 and 64. It is desirable to slow down. Similarly, in step S18, when the tip of the telescopic boom 32 stops on the turning limit lines 63 and 64, the control unit 50 causes the hoisting cylinder 35 to fall in a speed pattern that does not swing in the turning radius direction. It is desirable to reduce the speed. Such a speed pattern is determined by, for example, a swing cycle specified by the length from the tip of the telescopic boom 32 to the suspended load 40.

  Furthermore, the control part 50 performs a slow stop process according to the front-end | tip of the telescopic boom 32 being a control area (S15: No & S16: control area) (S19). The slow stop process is a process of slowly stopping at least one of the swing motor 31 and the hoisting cylinder 35. Typically, the control unit 50 determines the timing at which the tip of the telescopic boom 32 enters the restriction region, that is, the tip of the telescopic boom 32 is the third contour line 67 ′, the fourth contour line 68 ′, or the third contour line. The slow stop process is executed at the timing when it passes through the intersection C between 67 'and the fourth contour line 68'. The details of the restriction process will be described with reference to FIG.

  First, the control unit 50 performs notification processing (S31). The notification process is a process of notifying the operator that the tip of the telescopic boom 32 is located within the restriction region. In other words, the notification process is a process of notifying the operator that the turning of the upper swing body 30 and the collapse of the telescopic boom 32 should not be performed simultaneously. Although the specific method of notification is not particularly limited, for example, a message may be displayed on the display (not shown) of the overload prevention device, or a warning sound may be output from a speaker (not shown), An LED (not shown) or the like may be turned on.

  Next, the control part 50 judges the relationship between the extension line of the movement locus | trajectory of the front-end | tip of the telescopic boom 32 moved by the turning-over process, and a control area (S32). The extension line of the movement trajectory of the tip of the telescopic boom 32 can be estimated from the position of the tip of the telescopic boom 32 specified in steps S18 and S19, the turning speed, and the overturning speed. With reference to the example of FIG. 7, the process according to the relationship between the estimated extension line of the movement locus and the restriction region will be described.

  As shown in FIG. 7A, the control unit 50 determines that the extension line 71 ′ of the movement locus 71 of the telescopic boom 32 intersects the first contour line 62 ′ (S32: first). (Contour line), the turning motor 31 is gently stopped so that the tip of the telescopic boom 32 stops on the turning limit line 63 (S33). The slow stop of the turning motor 31 is common to step S17. Further, the control unit 50 continues to drive the hoisting cylinder 35 according to the operation signal from the hoisting lever.

  Further, as shown in FIG. 7B, the control unit 50 determines that the extension line 72 ′ of the movement locus 72 of the telescopic boom 32 and the second contour line 63 ′ intersect (S32: (Second contour line), the undulation cylinder 35 is gently stopped so that the tip of the telescopic boom 32 stops on the lower limit line 62 (S34). The slow stop of the hoisting cylinder 35 is common to step S18. Further, the control unit 50 continues to drive the turning motor 31 according to the operation signal from the turning lever.

  Further, as shown in FIG. 7C, the control unit 50 determines that the extension line 73 ′ of the movement locus 73 of the telescopic boom 32 and the intersection A intersect (S32: intersection A). The swing motor 31 and the hoisting cylinder 35 are gently stopped so that the tip of the telescopic boom 32 stops on the intersection point A (S35). The slow stop of the swing motor 31 is common with step S17, and the slow stop of the hoisting cylinder 35 is common with step S18.

[Operational effects of this embodiment]
According to the above embodiment, one or both of the turning motor 31 and the hoisting cylinder 35 is activated depending on the positional relationship between the extension lines 71 ′ to 73 ′ of the movement trajectories 71 to 73 of the tip of the telescopic boom 32 and the restriction region. Slowly stopped. And since the slow stop process is performed at the timing when the front-end | tip of the telescopic boom 32 approached into the control area | region, the distance required in order to make an actuator stop slowly slowly can be ensured. As a result, it is possible to prevent the tip of the telescopic boom 32 from entering the work limit area without suddenly stopping turning and overturning.

  Further, according to the second determination process according to the above embodiment, the restriction region having a size corresponding to the turning speed of the upper turning body 30 and the overturning speed of the telescopic boom 32 can be determined. It is possible to secure a distance necessary for safely and slowly stopping the fall of the telescopic boom 32. However, the method of determining the restriction area is not limited to the above example. For example, the restriction region may be a portion surrounded by the first contour line 62 ′ and the second contour line 63 ′ in a rectangular shape having the intersections A and B as the center of gravity or the center.

  FIG. 7A shows an example in which the movement locus 71 of the tip of the telescopic boom 32 intersects the fourth contour line 68 ′, and the extension line 71 ′ of the movement locus 71 intersects the first contour line 71 ′. However, the combination of intersecting sides (or vertices) is not limited to this. For example, in the example of FIG. 7A, the movement locus 71 may intersect with the third contour line 67 'or the intersection C, and the extension line 71' of the movement locus 71 may intersect with the first contour line 62 '. The same applies to FIGS. 7B and 7C.

  Further, when the left and right overhang amounts of the outriggers 23 and 24 are the same, the boundaries of the lodging limit lines 61 and 62 are different from the example of FIG. The control unit 50 in this case is, for example, a region sandwiched between straight lines extending from the turning center of the upper turning body 30 to the front outrigger 23 and a straight line extending from the turning center of the upper turning body 30 to the rear outrigger 24. A first lodging limit line is set to the sandwiched area. In addition, the control unit 50 is sandwiched by a straight line extending from the turning center of the upper turning body 30 to the right outriggers 23 and 24 and a straight line extending from the turning center of the upper turning body 30 to the left outriggers 23 and 24. The second lodging limit line is set to the specified area. Further, the control unit 50 sets a portion sandwiched between the lodging limit lines 61 and 62 among the straight lines extending from the upper swing body 30 to the outriggers 23 and 24 as a turning limit line.

DESCRIPTION OF SYMBOLS 10 ... Rough terrain crane 20 ... Lower traveling body 30 ... Upper turning body 31 ... Turning motor 32 ... Telescopic boom 36 ... Hoisting cylinder 37 ... Telescopic cylinder 38 ... Rope 50: Control unit 57: Operation unit

Claims (5)

A traveling body,
A revolving structure supported to be capable of revolving on the traveling body;
A boom supported by the swivel body in a undulating manner;
A turning actuator for turning the turning body;
A hoisting actuator for hoisting the boom,
A first operation unit that receives an operation for instructing the turning of the revolving structure;
A second operation unit for receiving an operation for instructing the boom to fall down;
A work vehicle comprising a control unit,
The control unit
In response to the simultaneous operation of the first operating unit and the second operating unit, the turning actuator causes the turning actuator to turn the turning body and causes the hoisting actuator to fall the boom.
A first determination process for determining a limit line indicating a boundary between a workable area where entry of the tip of the boom is allowed and a work limit area where entry is prohibited;
A second determination process for determining a restriction area for restricting the turning and falling process from the limit line to the workable area side;
A slow stop process for gently stopping at least one of the swing actuator and the hoisting actuator in response to the tip of the boom entering the restriction region by the swing overturning process;
In the first determination process,
The limit line indicating the boundary of the work limit area where entry of the tip of the boom that has fallen is prohibited is the first fall limit line having an arc shape with a first radius, and the first fall limit in the turning direction. A second lodging limit line adjacent to the line and having a second radius smaller than the first radius;
The limit line indicating the boundary of the work limit area where entry of the tip of the boom due to turning of the swing body is prohibited, and the adjacent end portions of the first and second fall limit lines Determine the turning limit line that connects them,
In the second determination process, an intersection of the second lodging limit line and the turning limit line is set as one vertex, an extension line of a predetermined length of the second lodging limit line is set as a first contour line, and the turning A graphic region having an extension line of a predetermined length of a limit line as a second contour line is determined as the restriction region,
In the above slow stop process,
In response to the extension of the movement trajectory of the tip of the boom moved by the turning overturning process intersecting the first contour line, the turning actuator is stopped so that the tip of the boom stops at the turning limit line. Stop slowly,
A work vehicle that slowly stops the hoisting actuator so that the tip of the boom stops at the second fall limit line in response to an extension line of the movement trajectory intersecting the second contour line.   In the slow stop process, the control unit loosens the swing actuator and the hoisting actuator so that the tip of the boom stops at the intersection in response to the extension line of the movement trajectory passing through the intersection. The work vehicle according to claim 1 to be stopped. In the second determination process, the control unit
The faster the turning speed of the revolving body, the longer the first contour line,
The work vehicle according to claim 1 or 2, wherein the second contour line is lengthened as the boom falling speed increases. The control unit
In the first determination process,
A first fall / slow stop line extending from the first fall limit line alongside the first fall limit line on the workable region side and indicating a boundary of a fall / slow stop region for gently stopping the fall of the boom;
A second lodging slow stop line extending along the second lodging limit line on the workable area side from the second lodging limit line and indicating a boundary of the lodging slow stop area;
A turning slow stop line that extends alongside the turning limit line on the workable region side from the turning limit line and that indicates a boundary of a turning slow stop region that gently stops the turning of the turning body;
In the second determination process, the first contour line, the second contour line, a third contour line that is an extension of a predetermined length of the second lodging slow stop line, and the turning slow stop line The work vehicle according to any one of claims 1 to 3, wherein the graphic region surrounded by a fourth contour line that is an extension line of a predetermined length is determined as the restriction region.   In the second determination process, the control unit includes the graphic surrounded by the first contour line, the second contour line, and a third contour line having an arc shape with a third radius centered on the intersection. The work vehicle according to claim 1, wherein an area is determined as the restriction area.

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