Work machine

1. A work machine comprising:

a work device having a boom, an arm, and a bucket;

a plurality of hydraulic actuators that drive the work device;

an operation device that outputs an operation signal in response to an operator's operation and that instructs the plurality of hydraulic actuators to be actuated; and

a controller that limits a velocity at which the work device approaches a predetermined design surface to be equal to or lower than a predetermined limiting velocity in such a manner that the work device is located onto or above the design surface when the operation device is operated, wherein

the controller

determines whether a work phase of the work device is compaction work on a basis of a posture of the bucket with respect to the design surface in a case in which the operation device instructs the work device to approach the design surface,

sets the limiting velocity, when determining that the work phase of the work device is the compaction work, to be higher than the limiting velocity when determining that the work phase of the work device is other than the compaction work, and

determines that the work phase of the work device is the compaction work when an angle formed between a bottom surface of the bucket and the design surface is equal to or greater than a predetermined value and the operation signal is an operation instructing the work device to approach the design surface.

2. The work machine according to claim 1 , wherein

the controller sets the limiting velocity when the controller determines that the work phase of the work device is the compaction work and a tip end of the work device is located in a first region surrounded by a first boundary set above the design surface and a second boundary set onto or below the design surface, to be higher than the limiting velocity when the controller determines that the work phase of the work device is other than the compaction work.

3. The work machine according to claim 1 , wherein

while it is defined that a direction in which the work device penetrates into below the design surface is positive in relation to a velocity direction of the limiting velocity,

the controller sets the direction of the limiting velocity to be positive when the work device is located in a second region surrounded by a second boundary set below the design surface and a third boundary set below the design surface in a case in which the controller determines that the work phase of the work device is the compaction work when the operation signal is an operation signal for giving an instruction of any one of arm dumping and arm crowding.

4. The work machine according to claim 1 , wherein

the plurality of hydraulic actuators include a boom cylinder that drives the boom, and

the controller changes a magnitude of the limiting velocity on a basis of a pressure of a rod side of the boom cylinder in a case of determining that the work phase of the work device is the compaction work.

5. The work machine according to claim 1 , wherein

the plurality of hydraulic actuators include a boom cylinder that drives the boom, and

the controller reduces a magnitude of the limiting velocity in response to an increase in a pressure of a rod side of the boom cylinder in a case of determining that the work phase of the work device is the compaction work.

6. The work machine according to claim 1 , wherein

the plurality of hydraulic actuators include a boom cylinder that drives the boom, and

while it is defined that a direction in which the work device penetrates into below the design surface is positive in relation to a velocity direction of the limiting velocity,

the controller sets the direction of the limiting velocity to be positive and changes a magnitude of the limiting velocity on a basis of a pressure of a rod side of the boom cylinder when a tip end of the work device is located in a second region surrounded by a second boundary set below the design surface and a third boundary set below the design surface in a case in which the controller determines that the work phase of the work device is the compaction work when the operation signal is an operation signal for giving an instruction of any one of arm dumping and arm crowding.

7. The work machine according to claim 1 , wherein

an angle formed between a bottom surface of the bucket and the design surface is a value obtained by subtracting an angle formed between the design surface and a reference plane from an angle formed between the bottom surface of the bucket and the reference plane, and an angle counterclockwise from the reference plane is defined as being positive.

8. The work machine according to claim 1 , further comprising:

a switch that switches over between validity and invalidity of processing for setting the limiting velocity when it is determined that the work phase of the work device is the compaction work, to be higher than the limiting velocity when the work phase determination section determines that the work phase is other than the compaction work.

9. A work machine, comprising:

a work device having a boom, an arm, and a bucket;

a plurality of hydraulic actuators that drive the work device;

an operation device that outputs an operation signal in response to an operator's operation and that instructs the plurality of hydraulic actuators to be actuated; and

a controller that limits a velocity at which the work device approaches a predetermined design surface to be equal to or lower than a predetermined limiting velocity in such a manner that the work device is located onto or above the design surface when the operation device is operated, wherein

the controller

determines whether a work phase of the work device is compaction work on a basis of a posture of the bucket with respect to the design surface in a case in which the operation device instructs the work device to approach the design surface,

sets the limiting velocity, when determining that the work phase of the work device is the compaction work, to be higher than the limiting velocity when determining that the work phase of the work device is other than the compaction, and

determines that the work phase of the work device is the compaction work when a rear end of a bottom surface of the bucket is closer to the design surface than a tip end of the bottom surface of the bucket and the operation signal is an operation signal instructing the work device to approach the design surface.

10. A work machine, comprising:

a work device having a boom, an arm, and a bucket;

a plurality of hydraulic actuators that drive the work device;

an operation device that outputs an operation signal in response to an operator's operation and that instructs the plurality of hydraulic actuators to be actuated; and

a controller that limits a velocity at which the work device approaches a predetermined design surface to be equal to or lower than a predetermined limiting velocity in such a manner that the work device is located onto or above the design surface when the operation device is operated, wherein

the controller

determines whether a work phase of the work device is compaction work on a basis of a posture of the bucket with respect to the design surface in a case in which the operation device instructs the work device to approach the design surface,

sets the limiting velocity, when determining that the work phase of the work device is the compaction work, to be higher than the limiting velocity when determining that the work phase of the work device is other than the compaction work, and

determines that the work phase of the work device is the compaction work when an angle formed between a bottom surface of the bucket and the design surface is equal to or greater than a predetermined value and the operation signal is an operation signal for giving an instruction of any one of boom lowering, arm dumping, and arm crowding.