JP2024000801A - Control device of construction machine, construction machine, and control method of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a construction machine capable of suppressing breakage of a hammer grab while suppressing increase in cycle time of a hammer grab operation.

SOLUTION: A control device includes: a detector 81 that is used to obtain a hammer grab height from a bottom 12 of a work target of a hammer grab operation; and a controller 101 that causes the free fall of a hammer grab 10 when the hammer grab height is higher than a set height Hs set above the bottom 12, and performs control to adjust a brake on a winch drum DR1 so that the descending speed of the hammer grab 10 approaches a predetermined target speed Vs when the hammer grab height is equal to or less than the set height Hs.

SELECTED DRAWING: Figure 9

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to technology for controlling construction machinery during hammer grab work.

Conventionally, construction machines equipped with hammer grabs have been known. A hammer grab is an attachment used for hammer grab work using the all-casing construction method. This hammer grab work involves excavating the earth and sand inside the casing by dropping the hammer grab inside a casing (cylindrical member) that has been pushed into the ground, and lifting the hammer grab that holds the excavated earth and sand into the casing. including the discharge work of discharging the earth and sand outside. During excavation work, the operator operates the brake pedal as appropriate to prevent damage to the hammer grab upon landing. Such a brake operation is difficult for the operator because it is performed in a situation where the operator cannot visually see the hammer grab inside the casing. Additionally, in recent years there has been a shortage of construction machinery operators. Therefore, it is desired to develop a control device that assists an operator in hammer grabbing work so that even an unskilled person can easily perform the hammer grabbing work.

Patent Document 1 discloses a control device for an excavating machine that aims to automate an excavating operation among a series of operations in a hammer grab operation so that even an inexperienced operator can easily operate the excavating operation. In the control device of Patent Document 1, when the bucket is placed in the upper part of the casing, the bucket is lowered at low speed by the power of the motor, and after passing through this low-speed section, the bucket is lowered at high speed by the power of the motor. After passing through this high-speed section, this control device causes the bucket to fall freely and penetrate into the ground.

Japanese Patent Application Publication No. 5-163885

As described above, in the control device of Patent Document 1, the bucket is hoisted down by the power of the motor in the low-speed section and the following high-speed section, so there is a problem that the cycle time of the hammer grab operation becomes long.

The present disclosure aims to provide a construction machine control device, a construction machine, and a construction machine control method that can suppress damage to the hammer grab while suppressing the cycle time of the hammer grab operation from increasing. .

What is provided is a control device for a construction machine that performs hammer grab work by dropping a hammer grab by letting out a wire rope from a winch drum, the height of the hammer grab being determined from the bottom of the workpiece of the hammer grab work. a detector used to obtain the hammer grab height; and if the hammer grab height is higher than the set height above the bottom, the hammer grab is caused to fall freely; and a controller that performs control to adjust a brake on the winch drum so that the descending speed of the hammer grab approaches a predetermined target speed when the speed is lower than a predetermined target speed.

In this control device, the controller allows the hammer grab to fall freely until it reaches the set height, so the hammer grab work cycle is lower than the conventional technology in which hoisting is lowered by motor power in low-speed and high-speed sections. It becomes possible to shorten the time. In addition, with this control device, when the height of the hammer grab reaches a set height, the controller adjusts the brake on the winch drum so that the descending speed of the hammer grab approaches a predetermined speed, thereby preventing the descending speed from becoming too large. be done. Therefore, this control device can suppress breakage of the hammer grab while suppressing an increase in the cycle time of the hammer grab operation.

Preferably, the controller controls to adjust a brake on the winch drum so that the wire rope is prevented from being unwound excessively from the winch drum after the hammer grab lands on the bottom. With this configuration, the wire rope is prevented from being excessively paid out from the winch drum after the hammer grab lands on the bottom, so it is possible to suppress the winch drum from continuing to rotate due to inertia after the hammer grab lands. This prevents the winding state of the wire rope relative to the winch drum from becoming disordered (so-called random winding) during the subsequent winding of the wire rope.

The control device may further include an input device that receives an input of the set height by an operator, and the controller may set the set height based on the input. With this configuration, the operator can freely set the set height in consideration of, for example, the state of the work object, the characteristics of the construction machine, the operator's skill, and the like.

The controller may determine the set height using the target speed and a target acceleration (deceleration) when the hammer grab descends. With this configuration, even if the operator is an unskilled person, an appropriate setting height can be automatically set by the controller. Further, with this configuration, the controller can set an appropriate setting height in consideration of the target speed and target acceleration (deceleration). Specifically, the controller uses the target speed and target acceleration (deceleration) to set the smallest possible set height, which allows the hammer grab to set the free fall distance as long as possible. , the cycle time can be reduced more effectively.

The control device further includes a load value detector that detects a hammer grab load that is a load of the hammer grab acting on the wire rope, and the controller is configured to detect whether the wire rope is Based on a load change in which the hammer grab load increases due to being wound up by the winch drum, a ground-off height that is a height position when the hammer grab leaves the bottom is determined, and the ground-off height is set as an origin. Preferably, the height of the hammer grab is calculated. With this configuration, the controller can acquire the height off the ground, which is the height position when the hammer grab separates from the bottom, for each hammer grab operation that is repeatedly performed. Moreover, the load value detector for detecting the hammer grab load is relatively often originally installed in the construction machine, and in this case, there is no need to separately add a load value detector, so it is possible to suppress an increase in cost.

The controller includes load change information regarding the load change that is input from the load value detector, and information from the time when the hammer grab leaves the bottom until the load change information is input from the load value detector to the controller. It is preferable that the ground clearance height is determined using a delay time. With this configuration, the height off the ground is determined more accurately, so the calculation accuracy of the hammer grab height is further improved.

It is preferable that the controller performs loosening control, which is a control for performing loosening work, when the operator performs a winding operation after the hammer grab lands on the bottom. With this configuration, after the hammer grab lands on the bottom in the hammer grab operation, the loosening operation can be smoothly started.

A construction machine according to the present disclosure includes the above-described control device and the winch drum. This construction machine can suppress breakage of the hammer grab while suppressing an increase in the cycle time of the hammer grab operation.

A method for controlling a construction machine according to the present disclosure is a method for performing hammer grab work by dropping a hammer grab by letting out a wire rope from a winch drum. The control method includes obtaining a hammer grab height that is the height of the hammer grab from the bottom of the work target of the hammer grab work, and when the hammer grab height is higher than a set height set above the bottom. allowing the hammer grab to fall freely, and adjusting a brake for the winch drum so that the descending speed of the hammer grab approaches a predetermined target speed when the height of the hammer grab is less than or equal to the set height; Be prepared. This control method can suppress breakage of the hammer grab while suppressing an increase in the cycle time of the hammer grab operation.

As described above, according to the present disclosure, there is provided a control device for a construction machine, a construction machine, and a control method for a construction machine that can suppress damage to the hammer grab while suppressing an increase in the cycle time of the hammer grab operation. provided.

1 is a side view showing a construction machine including a control device according to an embodiment of the present disclosure. FIG. 3 is a diagram showing a hydraulic circuit of the construction machine. FIG. 3 is a block diagram showing a functional configuration of the control device. It is a graph which shows an example of the change of the falling speed of the hammer grab controlled by the said control apparatus. It is a graph which shows another example of the change of the falling speed of the hammer grab controlled by the said control apparatus. It is a graph showing the relationship between the height position of the hammer grab with respect to the bottom of the work object and the load value. It is a graph showing the delay in the change in the load value measured by the load value detector with respect to the change in the actual load value. It is a flowchart which shows the arithmetic control operation|movement which the controller of the said control apparatus performs. It is a flowchart which shows the arithmetic control operation|movement which the said controller performs. It is a figure which shows the modification of the hydraulic circuit of the said construction machine.

Preferred embodiments of the present disclosure will be described with reference to the drawings.

FIG. 1 shows a crane 200 that is a construction machine according to the embodiment. This crane 200 can perform hammer grab work using the all-casing construction method. As shown in FIG. 1, in this hammer grab work, earth and sand inside the casing 11 is excavated by dropping the hammer grab 10 inside the casing 11, which is a cylindrical member pushed into the ground (underground) that is the work target. This includes excavation work and a discharge work of elevating the hammer grab 10 that holds the excavated earth and sand to discharge the earth and sand outside of the casing 11.

This crane 200 includes a lower body 201, an upper revolving body 202 rotatably supported on the lower body 201, an undulating member 204 supported on the upper revolving body 202 so that it can be raised and lowered, and a plurality of winches. , and a hammer grab 10.

The lower body 201 includes a traveling device such as a crawler traveling device, for example, and is configured to be self-propelled. However, the lower body only needs to support the upper revolving body 202 in a rotatable manner, and may be constituted by a structure such as a support stand that is not self-propelled.

The upper revolving body 202 includes a revolving frame 203 rotatably attached to the lower body 201, a cabin supported at the front of the revolving frame 203, and a counterweight supported at the rear of the revolving frame 203.

The undulating member 204 is constituted by a boom supported by the revolving frame 203 so that it can be undulated. However, the undulating member may include a boom and a jib rotatably supported at the tip of the boom. A gantry 207 is erected on the rotating frame 203. A lower spreader 210 is arranged at the upper end of the gantry 207. One end of a guy line 208 is connected to the tip of the undulating member 204, and an upper spreader 209 is connected to the other end of the guy line 208. Lower spreader 210 and upper spreader 209 are spaced apart from each other. A undulating wire rope 211 is wrapped around the lower spreader 210 and the upper spreader 209.

The plurality of winches include a main winch WC1, an auxiliary winch WC2, and a hoisting winch WC3. In this embodiment, the plurality of winches are supported by the upper revolving structure 202, but at least one of the plurality of winches may be supported by the undulating member 204, for example.

The undulation winch WC3 has a winch drum DR3 around which the undulation wire rope 211 is wound. The undulation winch WC3 reduces or expands the distance between the upper spreader 209 and the lower spreader 210 by winding or letting out the undulation wire rope 211. As the separation distance decreases or expands, the undulating member 204 is undulated.

The main winding winch WC1 is a device for winding and letting out the main winding wire rope R1. The auxiliary winding winch WC2 is a device for winding and feeding out the auxiliary winding wire rope R2.

FIG. 2 is a diagram showing a hydraulic circuit included in the crane 200. As shown in FIGS. 1 and 2, the main winding winch WC1 includes a main winding drum DR1, which is a winch drum around which the main winding wire rope R1 is wound, a main winding motor 34 that drives the main winding drum DR1, and a main winding motor 34 that drives the main winding drum DR1. It has a winding clutch brake 48 and a reduction gear 47.

The configuration of the auxiliary winch WC2 is substantially the same as the configuration of the main winch WC1. Therefore, in the hydraulic circuit of FIG. 2, the configuration of the main winch WC1 is depicted as a representative, and the configuration of the auxiliary winch WC2 is omitted. The auxiliary winding winch WC2 includes an auxiliary winding drum DR2, which is a winch drum around which the auxiliary winding wire rope R2 is wound, an auxiliary winding motor 35 that drives the auxiliary winding drum DR2, an auxiliary winding clutch brake 49, and a speed reducer 47. , has.

As shown in FIG. 1, the hammer grab 10 includes a body 10A, a grab 10B, and a crown 10C. The glove 10B is attached to the lower part of the body 10A so as to be openable and closable. The crown 10C is a member for switching the glove 10B between an open state and a closed state. In the specific example of FIG. 1, the crown 10C is located above the body 10A.

A main winding point sheave 205 and an auxiliary winding point sheave 206 are attached to the tip of the undulating member 204. The main winding wire rope R1 hangs down from the main winding point sheave 205 while being wound around the main winding point sheave 205. The auxiliary winding wire rope R2 hangs down from the auxiliary winding point sheave 206 in a state of being wound around the auxiliary winding point sheave 206. The main winding wire rope R1 is a wire rope for suspending the body 10A and the grab 10B of the hammer grab 10, and the auxiliary winding wire rope R2 is a wire rope for suspending the crown 10C.

The hammer grab 10 operates, for example, as follows. First, as the main winding wire rope R1 is let out from the main winding drum DR1, the hammer grab 10 falls within the casing 11 to the bottom 12 of the ground that is the work target (excavation target). The hammer grab 10 excavates the earth and sand at the bottom part 12 by using the energy accompanying the fall. Thereafter, the main winding wire rope R1 is wound up by the main winding winch WC1 and the grab 10B is closed, so that the earth and sand are held in the grab 10B. Then, the main winding wire rope R1 is further wound up by the main winding winch WC1, the hammer grab 10 is taken out of the casing 11, and the upper rotating body 202 rotates to move the hammer grab 10 above a predetermined position. An auxiliary winding wire rope R2 is let out from an auxiliary winding drum DR2 of a winding winch WC2. Then, the crown 10C fits into the body 10A of the hammer grab 10. As a result, the body 10A and the crown 10C are suspended from the auxiliary winding wire rope R2, and the glove 10B becomes openable. In this state, the main winding wire rope R1 is let out from the main winding drum DR1 of the main winding winch WC1, thereby opening the grab 10B and discharging earth and sand from the hammer grab 10 to the predetermined position.

Each of the main winding motor 34 and the auxiliary winding motor 35 is a hydraulic motor, and is connected to the hydraulic pump 31. The main winding motor 34 operates to rotate the main winding drum DR1 in either the feeding direction or the winding direction by being supplied with hydraulic oil discharged from the hydraulic pump 31. Similarly, the auxiliary winding motor 35 operates to rotate the auxiliary winding drum DR2 in either the feeding direction or the winding direction by receiving the hydraulic oil discharged from the hydraulic pump 31. The hydraulic pump 31 is driven by a drive source such as an engine (not shown).

The reducer 47 of the main winding winch WC1 reduces the rotation of the main winding motor 34, and transmits power (rotational force) from the main winding motor 34 to the main winding drum DR1. The reducer 47 of the auxiliary winding winch WC2 reduces the rotation of the auxiliary winding motor 35, and transmits power (rotational force) from the auxiliary winding motor 35 to the auxiliary winding drum DR2. Each of these speed reducers 47 has, for example, a planetary gear mechanism.

The main clutch brake 48 can be switched between a connected state and a free state. The main winding clutch brake 48 can adjust the degree of connection between the main winding motor 34 and the main winding drum DR1 between the connected state and the free state.

The connected state is a state in which the power of the main winding motor 34 can be transmitted to the main winding drum DR1. That is, the connected state is a state in which the main winding wire rope R1 can be paid out and wound up by the power of the main winding motor 34. Therefore, when the main winding motor 34 operates in the above-mentioned connected state, the power of the main winding motor 34 is transmitted to the main winding drum DR1 via the reduction gear 47, and the main winding drum DR1 rotates. When the main winding drum DR1 rotates, the main winding wire rope R1 is paid out or wound up.

The free state is a state in which the main winding wire rope R1 can be let out from the main winding drum DR1 by the weight of the hammer grab 10. That is, the free state is a state in which the main winding wire rope R1 can be let out from the main winding drum DR1 by the tension of the main winding wire rope R1, that is, a state in which the hammer grab 10 can freely fall. Therefore, in the free state, the main winding wire rope R1 can be paid out from the main winding drum DR1 without operating the main winding motor 34 in the feeding direction in which the main winding wire rope R1 is paid out.

Similarly, the auxiliary clutch brake 49 can be switched between a connected state and a free state. The auxiliary winding clutch brake 49 can adjust the degree of connection between the auxiliary winding motor 35 and the auxiliary winding drum DR2 between the connected state and the free state.

The connected state is a state in which the power of the auxiliary winding motor 35 can be transmitted to the auxiliary winding drum DR2. That is, the connected state is a state in which the auxiliary winding wire rope R2 can be paid out and wound up by the power of the auxiliary winding motor 35. Therefore, when the auxiliary winding motor 35 operates in the above-mentioned connected state, the power of the auxiliary winding motor 35 is transmitted to the auxiliary winding drum DR2 via the reduction gear 47, and the auxiliary winding drum DR2 rotates. When the auxiliary winding drum DR2 rotates, the auxiliary winding wire rope R2 is paid out or wound up.

The free state is a state in which the auxiliary winding wire rope R2 can be let out from the auxiliary winding drum DR2 by the weight of the hammer grab 10. That is, the free state is a state in which the auxiliary winding wire rope R2 can be let out from the auxiliary winding drum DR2 by the tension of the auxiliary winding wire rope R2. Therefore, in the free state, the auxiliary winding wire rope R2 can be paid out from the auxiliary winding drum DR2 without operating the auxiliary winding motor 35 in the direction of feeding out the auxiliary winding wire rope R2.

The main winding clutch brake 48 is capable of applying a braking force to the main winding drum DR1, that is, applying a brake to the main winding drum DR1. Specifically, the main winding clutch brake 48 can adjust the braking force applied to the main winding drum DR1.

Similarly, the auxiliary winding clutch brake 49 can apply a braking force to the auxiliary winding drum DR2, that is, it is possible to apply a brake to the auxiliary winding drum DR2. Specifically, the auxiliary volume clutch brake 49 can adjust the braking force applied to the auxiliary volume drum DR2.

In this embodiment, each of the main clutch brake 48 and the auxiliary clutch brake 49 is a so-called wet brake, and includes a case 40, a piston 42 that is displaced relative to the case 40 by hydraulic pressure applied from the pilot pump 36, and a plurality of A brake disc 41 (a plurality of clutch plates) is provided. Each of the plurality of brake discs 41 is, for example, a friction plate soaked in hydraulic oil.

The plurality of brake discs 41 can be switched between a state in which the plurality of brake discs 41 are in contact with each other and a state in which the plurality of brake discs 41 are separated from each other by the operation of the piston 42. Each of the main clutch brake 48 and the auxiliary clutch brake 49 is in the free state when the plurality of brake discs 41 are separated from each other, thereby allowing the hammer grab 10 to descend (free fall) under its own weight. become. Furthermore, each of the main volume clutch brake 48 and the auxiliary volume clutch brake 49 enters the connected state when the plurality of brake discs 41 are brought into contact with each other.

More specifically, each of the main volume clutch brake 48 and the auxiliary volume clutch brake 49 includes a spring 46. A pair of oil chambers 43 and 44 are formed in each case 40 of the main clutch brake 48 and the auxiliary clutch brake 49. The piston 42 has a partition 45 that partitions a pair of oil chambers 43 and 44. The spring 46 urges the piston 42 in a direction in which the plurality of brake discs 41 approach each other.

For example, when the hydraulic pressure applied from the pilot pump 36 to the pair of oil chambers 43 and 44 is the same, the piston 42 receiving the urging force of the spring 46 pushes the plurality of brake discs 41, so that the plurality of brake discs 41 They are in contact with each other. When the oil pressure applied to one oil chamber 44 from the pilot pump 36 becomes larger than the oil pressure applied to the other oil chamber 43 by a predetermined amount or more, the plurality of brake discs 41 become separated from each other. That is, in each of the main clutch brake 48 and the auxiliary clutch brake 49, the degree of contact between the plurality of brake discs 41 changes depending on the difference between the oil pressure applied to the oil chamber 44 and the oil pressure applied to the oil chamber 43. . Therefore, the main winding clutch brake 48 can adjust the braking force on the main winding drum DR1 according to the difference between the oil chamber 43 and the oil chamber 44, and the auxiliary winding clutch brake 49 can adjust the braking force on the main winding drum DR1 according to the difference between the oil chamber 43 and the oil chamber 44. The braking force applied to the auxiliary drum DR2 can be adjusted according to the difference between the two.

Crane 200 includes a control device for operating hammer grab 10 by controlling the operations of main hoisting drum DR1 and auxiliary hoisting drum DR2. FIG. 3 is a block diagram showing the functional configuration of the control device. As shown in FIGS. 2 and 3, this control device includes a plurality of operating devices, a plurality of valves, a drum rotation detector, a monitor switch 105, a load value detector 106, a temporary cancel switch 107, A controller 101 is provided.

The plurality of operating devices include a main winding winch operating device 51, an auxiliary winding winch operating device 53, a main winding brake operating device 52, and an auxiliary winding brake operating device 54.

The main winch operating device 51 includes a main winch lever 51A to which an operator's main winch operation is input, and a main winch lever input detector 51B to detect the direction and operation amount of the input main winch operation. . The main winding lever input detector 51B inputs the detection result to the controller 101. The main winding winch operation includes a winding operation for winding up the main winding wire rope R1, and a feeding operation for letting out the main winding wire rope R1.

The auxiliary winding winch operating device 53 includes an auxiliary winding lever 53A to which an operator's auxiliary winding winch operation is input, and an auxiliary winding lever input detector 53B that detects the direction and operation amount of the inputted auxiliary winding winch operation. . The auxiliary winding lever input detector 53B inputs the detection result to the controller 101.

The main volume brake operating device 52 includes a main volume pedal 52A to which a main volume brake operation by an operator is input.

The auxiliary winding brake operating device 54 includes an auxiliary winding pedal 54A to which an auxiliary winding brake operation by an operator is input.

The plurality of valves include a main winding valve group for controlling the operation of the main winding drum DR1 and an auxiliary winding valve group for controlling the operation of the auxiliary winding drum DR2. As shown in FIG. 2, the main volume valve group includes a main volume control valve 32, a payout proportional valve 61A, a take-up proportional valve 61B, a main volume brake control proportional valve 62, a main volume pedal proportional valve 67, It includes a brake system switching valve 65, a mode switching valve 66, and an emergency brake switching valve 69. The configuration of the auxiliary volume valve group is substantially the same as the configuration of the main volume valve group. Therefore, in the hydraulic circuit of FIG. 2, the main volume valve group is depicted as a representative, and the illustration of the auxiliary volume valve group is omitted. The auxiliary volume valve group includes an auxiliary volume control valve 33, a payout proportional valve 63A, a take-up proportional valve 63B, an auxiliary volume brake control proportional valve 64, an auxiliary volume pedal proportional valve 68, a brake system switching valve 65, It includes a mode switching valve 66 and an emergency brake switching valve 69.

The main winding control valve 32 is interposed between the hydraulic pump 31 and the main winding motor 34 , and the auxiliary winding control valve 33 is interposed between the hydraulic pump 31 and the auxiliary winding motor 35 . Each of the main winding control valve 32 and the auxiliary winding control valve 33 has a feeding pilot port and a winding pilot port.

The main winding control valve 32 is held at a neutral position and isolates the main winding motor 34 from the hydraulic pump 31 when no pilot pressure is applied to both pilot ports. The main winding control valve 32 opens to form an oil passage for rotating the main winding motor 34 in the feeding direction when pilot pressure is applied to the feeding pilot port. The main winding control valve 32 opens to form an oil passage for rotating the main winding motor 34 in the winding direction when pilot pressure is applied to the winding pilot port.

Similarly, the auxiliary winding control valve 33 is held at the neutral position and isolates the auxiliary winding motor 35 from the hydraulic pump 31 when no pilot pressure is applied to both pilot ports. The auxiliary winding control valve 33 opens to form an oil passage for rotating the auxiliary winding motor 35 in the feeding direction when pilot pressure is applied to the feeding pilot port. The auxiliary winding control valve 33 opens to form an oil passage for rotating the auxiliary winding motor 35 in the winding direction when pilot pressure is applied to the winding pilot port.

The proportional feed valve 61A is interposed between a hydraulic power source (not shown) and the feed pilot port of the main winding control valve 32. The feed proportional valve 61A is, for example, an electromagnetic proportional valve. The proportional payout valve 61A generates a pilot pressure that is a secondary pressure in accordance with a main winding payout command input from the controller 101, and inputs the pilot pressure to the payout pilot port of the main winding control valve 32. Thereby, the opening degree of the main winding control valve 32 is adjusted to a magnitude according to the main winding payout command, and the main winding motor 34 rotates in the feeding direction at a speed corresponding to the pilot pressure.

The winding proportional valve 61B is interposed between the hydraulic pressure source and the winding pilot port of the main winding control valve 32. The winding proportional valve 61B is, for example, an electromagnetic proportional valve. The winding proportional valve 61B generates a pilot pressure which is a secondary pressure according to the main winding command input from the controller 101, and inputs the pilot pressure to the winding pilot port of the main winding control valve 32. Thereby, the opening degree of the main winding control valve 32 is adjusted to a size according to the main winding command, and the main winding motor 34 rotates in the winding direction at a speed according to the pilot pressure.

Similarly, the proportional feed valve 63A is interposed between the hydraulic pressure source and the feed pilot port of the auxiliary winding control valve 33. The feed proportional valve 63A is, for example, an electromagnetic proportional valve. The proportional feed valve 63A generates a pilot pressure that is a secondary pressure in accordance with the auxiliary winding feed-out command input from the controller 101, and inputs the pilot pressure to the feeding pilot port of the auxiliary winding control valve 33. Thereby, the opening degree of the auxiliary winding control valve 33 is adjusted to a size according to the auxiliary winding payout command, and the auxiliary winding motor 35 rotates in the feeding direction at a speed according to the pilot pressure.

The winding proportional valve 63B is interposed between the hydraulic pressure source and the winding pilot port of the auxiliary winding control valve 33. The winding proportional valve 63B is, for example, an electromagnetic proportional valve. The take-up proportional valve 63B generates a pilot pressure, which is a secondary pressure, according to the auxiliary winding command input from the controller 101, and inputs the pilot pressure to the winding pilot port of the auxiliary winding control valve 33. Thereby, the opening degree of the auxiliary winding control valve 33 is adjusted to a size according to the auxiliary winding winding command, and the auxiliary winding motor 35 rotates in the winding direction at a speed according to the pilot pressure. In addition, the pilot pump 36 may be sufficient as the said hydraulic pressure source, and the pilot pump 36 may be a different pump.

The main volume brake control proportional valve 62 is interposed between the pilot pump 36 and the main volume clutch brake 48 . The main volume brake control proportional valve 62 is, for example, an electromagnetic proportional valve. The main volume brake control proportional valve 62 generates secondary pressure (main volume pilot pressure) according to the main volume brake command input from the controller 101, and this secondary pressure is applied to the oil chamber 43 of the main volume clutch brake 48. is input. That is, the main volume brake control proportional valve 62 can generate a braking force in the main volume clutch brake 48 according to the main volume brake command input from the controller 101.

Similarly, the auxiliary volume brake control proportional valve 64 is interposed between the pilot pump 36 and the auxiliary volume clutch brake 49. The auxiliary brake control proportional valve 64 is, for example, an electromagnetic proportional valve. The auxiliary winding brake control proportional valve 64 generates secondary pressure (auxiliary winding pilot pressure) according to the auxiliary winding brake command input from the controller 101, and this secondary pressure is applied to the oil chamber 43 of the auxiliary winding clutch brake 49. is input. That is, the auxiliary winding brake control proportional valve 64 can generate a braking force in the auxiliary winding clutch brake 49 according to the auxiliary winding brake command input from the controller 101.

The main volume pedal proportional valve 67 is interposed between the pilot pump 36 and the main volume clutch brake 48 . The main volume pedal proportional valve 67 generates a secondary pressure (main volume pilot pressure) according to the amount of main volume brake operation inputted to the main volume pedal 52A by the operator, and this secondary pressure is applied to the main volume clutch. It is input to the oil chamber 43 of the brake 48. That is, the main volume pedal proportional valve 67 can generate a braking force in the main volume clutch brake 48 according to the amount of operation of the main volume brake by the operator.

Similarly, the auxiliary volume pedal proportional valve 68 is interposed between the pilot pump 36 and the auxiliary volume clutch brake 49. The auxiliary winding pedal proportional valve 68 generates a secondary pressure (auxiliary winding pilot pressure) according to the amount of auxiliary winding brake operation inputted to the auxiliary winding pedal 54A by the operator, and this secondary pressure is applied to the auxiliary winding clutch. It is input to the oil chamber 43 of the brake 49. That is, the auxiliary volume pedal proportional valve 68 can generate a braking force in the auxiliary volume clutch brake 49 according to the amount of operation of the auxiliary volume brake by the operator.

The mode switching valve 66 is a switching valve for switching between a state in which a detour oil passage is formed and a state in which a proportional valve oil passage is formed. The mode switching valve 66 is interposed between the brake system switching valve 65 and the main clutch brake 48 .

The bypass oil passage is an oil passage through which the pilot pump 36 bypasses the main volume brake control proportional valve 62 and the main volume pedal proportional valve 67 and is connected to the oil chamber 43 of the main volume clutch brake 48 . That is, the detour oil path is an oil path through which the pilot pump 36 is connected to the oil chamber 43 of the main clutch brake 48 without going through these proportional valves 62 and 67.

The proportional valve oil passage is an oil passage through which the pilot pump 36 is connected to the oil chamber 43 of the main volume clutch brake 48 via either the main volume brake control proportional valve 62 or the main volume pedal proportional valve 67. The proportional valve oil passage includes a brake control proportional valve oil passage and a pedal proportional valve oil passage. The brake control proportional valve oil passage is an oil passage through which the pilot pump 36 is connected to the oil chamber 43 of the main volume clutch brake 48 via the main volume brake control proportional valve 62. The pedal proportional valve oil passage is an oil passage through which the pilot pump 36 is connected to the oil chamber 43 of the main volume clutch brake 48 via the main volume pedal proportional valve 67 .

Specifically, for example, the mode switching valve 66 is set to a detour oil passage forming position (the right position in FIG. 2), which is a position where a detour oil passage is formed, and a proportional valve oil position, in accordance with a command input from the controller 101. It may be a two-position electromagnetic switching valve having a spool that can be switched between a proportional valve oil passage forming position (left side position in FIG. 2), which is a position where a passage is formed. In the specific example shown in FIG. 2, when the solenoid of the mode switching valve 66 is in a non-energized state, the spool of the mode switching valve 66 is arranged at the detour oil path forming position, and when the solenoid of the mode switching valve 66 is in an energized state, , the spool of the mode switching valve 66 is arranged at the proportional valve oil path forming position. However, the structure of the mode switching valve 66 is not limited to this specific example. The mode switching valve 66 is configured such that when the solenoid is in an energized state, the spool is placed in a detour oil path forming position, and when the solenoid is in a de-energized state, the spool is placed in a proportional valve oil path forming position. You can leave it there.

The brake system switching valve 65 is a switching valve for switching between a state in which the brake control proportional valve oil passage is formed and a state in which the pedal proportional valve oil passage is formed. Brake system switching valve 65 is interposed between proportional valves 62 and 67 and mode switching valve 66.

Specifically, for example, the brake system switching valve 65 moves from the brake control proportional valve oil passage forming position (lower part of FIG. A two-position electromagnetic switch with a spool that can be switched between the side position (side position) and the pedal proportional valve oil passage forming position (upper position in Figure 2), which is the position where the pedal proportional valve oil passage is formed. It may also be a valve. In the specific example shown in FIG. 2, when the solenoid of the brake system switching valve 65 is in a de-energized state, the spool of the brake system switching valve 65 is placed in the pedal proportional valve oil path forming position, and the solenoid of the brake system switching valve 65 is in the non-energized state. When in the excited state, the spool of the brake system switching valve 65 is placed at the brake control proportional valve oil path forming position. However, the structure of the brake system switching valve 65 is not limited to this specific example. The brake system switching valve 65 has a spool disposed in a pedal proportional valve oil passage forming position when the solenoid is in an energized state, and a spool in a brake control proportional valve oil passage forming position when the solenoid is in a non-energized state. It may be configured so that

The mode switching valve 66 of the auxiliary volume valve group is a switching valve for switching between a state in which a detour oil passage is formed and a state in which a proportional valve oil passage is formed. The brake system switching valve 65 of the auxiliary volume valve group is a switching valve for switching between a state in which the brake control proportional valve oil passage is formed and a state in which the pedal proportional valve oil passage is formed. The configurations of the brake system switching valve 65 and mode switching valve 66 of the auxiliary volume valve group are substantially the same as the configurations of the brake system switching valve 65 and mode switching valve 66 of the main volume valve group described above. Detailed explanation will be omitted.

The emergency brake switching valve 69 is a switching valve for switching between a pump connected state in which the oil chamber 44 of the main clutch brake 48 is connected to the pilot pump 36 and a tank connected state in which the oil chamber 44 is connected to the tank. be. Specifically, for example, the emergency brake switching valve 69 has a supply position (left side position in FIG. 2) that allows hydraulic oil from the pilot pump 36 to be supplied to the oil chamber 44, and a supply position that allows the hydraulic oil from the pilot pump 36 to be supplied to the oil chamber 44; It may be a two-position electromagnetic switching valve having a spool that can be switched between a discharge position (right position in FIG. 2) that allows oil to be discharged from the oil chamber 44 into the tank. .

In normal times, the controller 101 sets the spool of the emergency brake switching valve 69 to the supply position, as shown in FIG. 2, and brings the emergency brake switching valve 69 into the pump connected state. On the other hand, in an emergency, the controller 101 switches the spool of the emergency brake switching valve 69 from the supply position to the discharge position. That is, the state of the emergency brake switching valve 69 is switched from the pump connected state to the tank connected state, and the oil chamber 44 is connected to the tank. As a result, the main winding drum DR1 is in a state where a braking force is generated, that is, the main winding drum DR1 is braked, so that the rotation of the main winding drum DR1 is decelerated and stopped. The configuration of the emergency brake switching valve 69 of the auxiliary volume valve group is substantially the same as the configuration of the emergency brake switching valve 69 of the main volume valve group described above, so a detailed explanation thereof will be omitted.

The drum rotation detector includes a main winding rotation sensor 81 and an auxiliary winding rotation sensor 82. The main winding rotation sensor 81 detects the main winding rotation amount ωm, which is the rotation amount of the main winding drum DR1, and inputs the detection result of the main winding rotation amount ωm to the controller 101. The auxiliary winding rotation sensor 82 detects the auxiliary winding rotation amount ωa, which is the rotation amount of the auxiliary winding drum DR2, and inputs the detection result of the auxiliary winding rotation amount ωa to the controller 101. Note that the main winding rotation sensor 81 may be a sensor that detects the movement of another member corresponding to the amount of rotation of the main winding drum DR1 (for example, the amount of rotation of the main winding point sheave 205). Similarly, the auxiliary winding rotation sensor 82 may be a sensor that detects the movement of another member corresponding to the amount of rotation of the auxiliary winding drum DR2 (for example, the amount of rotation of the auxiliary winding point sheave 206).

The monitor switch 105 is an input device used to set the weight of the hammer grab, which is the weight of the hammer grab 10. When the operator wants to set the weight of the hammer grab, the operator presses the monitor switch 105 and the weight of the hammer grab is stored in the controller 101. The monitor switch 105 may be provided, for example, on an unillustrated monitor placed in the cabin of the revolving upper structure 202, or may be provided on a portable information terminal that can be operated by an operator outside the revolving upper structure 202. Good too.

The load value detector 106 is a sensor that can detect a load value that correlates to the weight of the hammer grab. In this embodiment, the load value detector 106 is a sensor that detects the load value acting on the main wire rope R1. The load value detector 106 inputs the detection result of the load value to the controller 101. Since the load value acting on the main winding wire rope R1 is a value that correlates to the weight of the hammer grab, the controller 101 can acquire information regarding the weight of the hammer grab based on the detection result input from the load value detector 106. can. Specifically, for example, the load value detector 106 may include a load cell connected to the main winding wire rope R1.

Generally, cranes are equipped with a moment limiter (overload prevention device). This moment limiter uses information such as the length of the undulating member including the boom, the angle (attitude) of the undulating member, and the tension of the rope to calculate the moment acting on the crane, and if the calculated moment exceeds the allowable range. and stop the crane operation or issue an alarm. This moment limiter calculates the moment using the tension of the wire rope detected by a load value detector such as a load cell. The load value detector 106 of the crane 200 according to this embodiment is also used as a detector for calculating the moment.

The temporary cancel switch 107 is an input device that is input by the operator when the operator wants to temporarily cancel the automatic control of the brakes by the control device.

Controller 101 (mechatronic controller) controls the operation of crane 200. The controller 101 includes an arithmetic processing unit such as a CPU and an MPU, and a memory.

As shown in FIG. 3, the controller 101 includes a main drum winding layer calculating section 108, an auxiliary drum winding layer calculating section 109, an initial setting section 110, a hammer grab height calculating section 111, and a control state switching section 112. , landing automatic brake control calculation section 113, impact force adjustment control calculation section 114, loosening control calculation section 115 (no control calculation section 115), and automatic brake invalidation control calculation section 116 (brake control invalidation calculation section 116). , a main volume brake control proportional valve command current value calculation section 117 , and a switching valve command current value calculation section 118 .

The main winding drum winding layer calculation unit 108 calculates the winding layer of the main winding wire rope R1 wound on the main winding drum DR1 using the main winding rotation amount ωm detected by the main winding rotation sensor 81 of the drum rotation detector. do. The winding layer refers to the number of layers of the main winding wire rope R1 wound around the main winding drum DR1. Information such as the size of the main winding drum DR1 including the diameter and axial length of the main winding drum DR1, and the diameter of the main winding wire rope R1 is stored in the controller 101 in advance. Therefore, the main winding drum winding layer calculation unit 108 can obtain the number of rotations of the main winding drum DR1 from the reference position using the main winding rotation amount ωm, and the number of layers (windings) of the main winding wire rope R1 at that point in time. layers) can also be calculated.

The auxiliary winding drum winding layer calculation unit 109 calculates the winding layer of the auxiliary winding wire rope R2 wound on the auxiliary winding drum DR2 using the auxiliary winding rotation amount ωa detected by the auxiliary winding rotation sensor 82 of the drum rotation detector. do. The winding layer refers to the number of layers of the auxiliary winding wire rope R2 wound around the auxiliary winding drum DR2. Information such as the size of the auxiliary winding drum DR2 including the diameter and axial length of the auxiliary winding drum DR2, and the diameter of the auxiliary winding wire rope R2 is stored in the controller 101 in advance. Therefore, the auxiliary winding drum winding layer calculation unit 109 can obtain the number of rotations of the auxiliary winding drum DR2 from the reference position using the auxiliary winding rotation amount ωa, and the number of layers (windings) of the auxiliary winding wire rope R2 at that point in time. layers) can also be calculated.

The initial setting section 110 sets the weight of the hammer grab. The initial setting unit 110 may calculate the weight of the hammer grab using, for example, the load value detected by the load value detector 106. Specifically, the initial setting unit 110 sets the load value detected by the load value detector 106 at the time when the operator presses the monitor switch 105 as the hammer grab weight, and stores the set hammer grab weight in the memory. It may be configured to do so. Further, the initial setting unit 110 may set an input value (for example, a numerical value) input by the operator to an input device (not shown) as the weight of the hammer grab.

The hammer grab height calculation unit 111 calculates the hammer grab height, which is the height of the hammer grab 10 at that point in time, using the bottom 12 of the hole at that point in the work object (excavation object) as the origin. The hammer grab height has a positive value when the hammer grab 10 is above the bottom 12. The hammer grab height calculation unit 111 periodically and repeatedly calculates the hammer grab height during the hammer grab operation, thereby acquiring the hammer grab height during the hammer grab operation in real time. The hammer grab height calculating section 111 can calculate the hammer grab height using the detection result of the main winding rotation amount ωm inputted to the controller 101 from the main winding rotation sensor 81 of the drum rotation detector. The hammer grab height calculating section 111 uses the detection result of the main winding rotation amount ωm inputted to the controller 101 from the main winding rotation sensor 81 and the number of layers of the main winding wire rope R1 calculated by the main winding drum winding layer calculating section 108. By calculating the hammer grab height using (winding layer) and , it is possible to obtain a more accurate hammer grab height that takes the number of layers into consideration.

The hammer grab height calculation unit 111 can obtain the origin, which is the reference for the hammer grab height, that is, the position of the bottom 12 of the hole, for example, as follows. The hammer grab height calculation unit 111 calculates the load value detected by the load value detector 106 during the process in which the main winding wire rope R1 is wound up by the main winding drum DR1 from a state where the hammer grab 10 is in contact with the bottom 12 of the hole. The height off the ground, which is the height position when the hammer grab 10 separates from the bottom 12, can be determined based on the load change that increases. The hammer grab height calculation unit 111 sets this height off the ground as the origin at that point.

The control state switching unit 112 determines which of a plurality of preset control states the crane 200 is in. The plurality of control states include an automatic brake state upon landing, an impact force adjustment state, a loosening control state (no control state), and an automatic brake invalid control state (brake control invalid state).

The control state switching unit 112 can select one of a plurality of control states using information such as the height of the hammer grab, the weight of the hammer grab, the main winding pedal input, the load value, and the input to the temporary cancel switch 107. can. Details of the control state switching section 112 will be described later.

When the control state switching unit 112 determines the control state to be the automatic landing brake state, the landing automatic brake control calculation unit 113 executes the landing automatic brake control. Details of the automatic brake control upon landing will be described later.

The impact force adjustment control calculation unit 114 executes impact force adjustment control when the control state switching unit 112 determines the control state to be the impact force adjustment state. Details of the impact force adjustment control will be described later.

The loosening control calculating section 115 (non-control calculating section 115) executes loosening control when the control state switching section 112 determines the control state to be the loosening control state (no control state). Details of the loosening control will be described later.

The automatic brake invalidation control calculation unit 116 (brake control invalidation calculation unit 116) executes automatic brake invalidation control when the control state switching unit 112 determines the control state to be the automatic brake invalidation control state (brake control invalidation state). Details of the automatic brake invalidation control will be described later.

The main volume brake control proportional valve command current value calculation unit 117 calculates a main volume brake command (command current value ) is calculated.

The switching valve command current value calculation unit 118 inputs a command (command current value) to be input to the brake system switching valve 65 and the mode switching valve 66 based on the calculation results calculated by each of the calculation units 113 to 116. Calculate the command (command current value) for

Hereinafter, the impact force adjustment control, automatic brake control upon landing, loosening control, and automatic brake invalidation control performed by the control device of the crane 200 according to the present embodiment will be described.

[Impact force adjustment control]
In this impact force adjustment control, the controller 101 causes the hammer grab 10 to fall freely when the height of the hammer grab is higher than a set height Hs set above the bottom portion 12, and when the height of the hammer grab is lower than the set height Hs. In some cases, the braking force applied to the main drum DR1 is adjusted so that the descending speed of the hammer grab 10 approaches a predetermined target speed Vs (see FIG. 4).

In this impact force adjustment control, the controller 101 drops the hammer grab 10 in the order of a work start position P1, a deceleration control start position P2, and a landing position P3, as shown in FIG.

The work start position P1 is a position where the excavation work by the hammer grab 10 is started. This work start position P1 is a position where at least a portion of the hammer grab 10 is placed inside the casing 11 and the hammer grab 10 is placed above the casing 11. Before the impact force adjustment control is initiated, the operator places the hammer grab 10 at the work start position P1 by manually operating the main winding lever 51A. The work start position P1 is a position above the set height Hs.

The deceleration control start position P2 is a position where deceleration control is started to bring the descending speed of the hammer grab 10 closer to the target speed.

The landing position P3 is a position where the hammer grab 10 lands on the bottom 12 of the hole.

The target speed Vs is set to a speed that takes into consideration the impact force upon landing so that damage to the hammer grab 10 can be suppressed even if the hammer grab 10 lands at this target speed Vs. It is preferable that the target speed Vs is set to a value as large as possible within an allowable range so that the excavation work can be performed efficiently. The target speed Vs is a value that is preset in consideration of, for example, the characteristics of the hammer grab 10 such as the weight of the hammer grab 10 and the strength of the hammer grab 10, the work environment such as the soil quality of the bottom 12 of the hole to be worked, etc. . Further, the target speed Vs may be set in consideration of the soil quality of the work target (soil condition, soil hardness, etc.). Note that, as shown in FIG. 4, the control device may be configured so that the operator can adjust the target speed Vs to a desired value. In this case, the control device further includes a setting input device 91 shown in FIG. 2, the operator inputs the target speed Vs into the setting input device 91, and the controller 101 sets the target speed Vs based on the input.

The set height Hs may be set based on information input by an operator. In this case, the operator inputs the set height Hs into the setting input device 91, and the controller 101 sets the set height Hs based on the input.

Further, the set height Hs may be automatically set by the controller 101. In this case, the controller 101 may determine the set height Hs using, for example, the target speed and target acceleration (deceleration). A method for determining the set height Hs by the controller 101 will be described later.

FIG. 4 is a graph showing an example of a change in the falling speed of the hammer grab 10 in the impact force adjustment control performed by the control device according to the present embodiment.

The controller 101 starts impact force adjustment control with the hammer grab 10 placed at the work start position P1 shown in FIG. Impact force adjustment control includes free fall control performed when the hammer grab 10 is in the range from the work start position P1 to the deceleration control start position P2, and free fall control performed when the hammer grab 10 is in the range from the deceleration control start position P2 to the landing position P3. This includes deceleration control that is sometimes performed.

The impact force adjustment control calculation unit 114 of the controller 101 executes impact force adjustment control when the control state switching unit 112 switches the control state to the impact force adjustment state. The control state switching unit 112 may switch the control state to the impact force adjustment state, for example, in response to an instruction from an operator to start excavation work. In this case, the control device includes a start instruction input device 92 shown in FIG. Switch to force adjustment state.

When the control state is switched to the impact force adjustment state, the impact force adjustment control calculation unit 114 performs control to switch the main winding clutch brake 48 to the free state (time t1 in FIG. 4). As a result, as shown in FIG. 4, the hammer grab 10 starts to fall freely due to its own weight.

Specifically, when the control state is switched to the impact force adjustment state, the impact force adjustment control calculation unit 114 positions the spool of the mode switching valve 66 at the proportional valve oil path forming position (the left position in FIG. 2). This command is output to the mode switching valve 66. As a result, the main winding clutch brake 48 is switched to the free state, and the hammer grab 10 becomes in a state where it can freely fall due to its own weight.

Further, in this embodiment, when the control state is switched to the impact force adjustment state, the impact force adjustment control calculation unit 114 moves the spool of the brake system switching valve 65 to the brake control proportional valve oil path forming position (lower side in FIG. 2). A command is output to the brake system switching valve 65 for arranging the brake system at the brake system switching valve 65. As a result, the impact force adjustment control calculation unit 114 applies a brake force to the main volume clutch brake according to the main volume brake command (command current value) input from the impact force adjustment control calculation unit 114 to the main volume brake control proportional valve 62. 48.

When the hammer grab 10 is in the range from the work start position P1 to the deceleration control start position P2, the impact force adjustment control calculation unit 114 controls the operation of the hammer grab 10 so that the main winding clutch brake 48 does not generate a braking force. Therefore, in the time period from time t1 to time t2 in FIG. 4, the descending speed of the hammer grab 10 (hammer grab speed) becomes a large value exceeding the target speed Vs, as shown by the solid line in FIG. In the impact force adjustment control, the hammer grab height calculating section 111 periodically calculates the hammer grab height.

When the hammer grab 10 freely falls to the deceleration control start position P2 and the hammer grab height reaches the set height Hs, the impact force adjustment control calculation unit 114 starts deceleration control.

In this deceleration control, the impact force adjustment control calculation unit 114 adjusts the braking force on the main winding drum DR1 so that the descending speed of the hammer grab 10 approaches the target speed Vs. The impact force adjustment control calculation unit 114 inputs a main winding brake command (command current value) to the main winding brake control proportional valve 62 so that the lowering speed of the hammer grab 10 approaches the target speed Vs, and the lowering speed of the hammer grab 10 approaches the target speed Vs. A braking force that approaches the speed Vs is generated in the main clutch brake 48. As a result, the descending speed of the hammer grab 10 is adjusted to the target speed Vs as shown in FIG. 4, and the descending speed when the hammer grab 10 falls to the landing position P3 and lands on the bottom 12 of the hole becomes approximately the target speed Vs. .

In this embodiment, the impact force adjustment control calculation unit 114 provides feedback to adjust the opening degree of the main winding brake control proportional valve 62 so that the speed difference, which is the difference between the target speed Vs and the descending speed of the hammer grab 10, becomes zero. Control may also be performed. In this case, the impact force adjustment control calculation unit 114 calculates a main volume brake command to the main volume brake control proportional valve 62 so that the speed difference becomes zero, and transmits the main volume brake command to the main volume brake control proportional valve 62. Enter. As the feedback control method, for example, PID control, PI control, or P control may be used. In the case of PID control, the impact force adjustment control calculation unit 114 may calculate the main winding brake command using, for example, the following equation.

u(t)=Kp×e(t)+Ki∫e(t)dt+Kd(de(t)/dt)
In the above formula, "u" is the main winding brake command, "Kp", "Ki", and "Kd" are PID gains (proportional gain, integral gain, and differential gain), and "e" is This is the speed difference. The PID gain is set in advance and stored in the controller 101.

As described above, in the control device according to the present embodiment, the controller 101 causes the hammer grab 10 to fall freely until the hammer grab height reaches the set height Hs, so that the lowering by the power of the motor is prevented in the low speed section and the high speed section. Compared to conventional techniques, it is possible to shorten the cycle time of the hammer grab operation. That is, until the hammer grab height reaches the set height Hs, the hammer grab 10 can be lowered at a high speed associated with free fall, so the cycle time can be reduced. In addition, in this control device, when the height of the hammer grab reaches the set height Hs, the controller 101 adjusts the braking force on the main drum DR1 so that the descending speed of the hammer grab 10 approaches the target speed Vs, so that the descending speed increases. It is suppressed from becoming too large. Therefore, this control device can suppress breakage of the hammer grab 10 while suppressing an increase in the cycle time of the hammer grab operation. On the other hand, if the deceleration control as in this embodiment is not performed, the hammer grab 10 will land on the bottom 12 at a high speed exceeding the target speed Vs even after time t2, as shown by the broken line in FIG. Become.

FIG. 5 is a graph showing a modification example of the change in the falling speed of the hammer grab 10 in the impact force adjustment control performed by the control device according to the present embodiment. The modification shown in FIG. 5 differs from the case shown in FIG. 4 in that the position at which the hammer grab 10 starts excavation work (work start position) is below the set height Hs. In this modification, the following control is performed.

The impact force adjustment control in this modification includes the deceleration control as described above, but does not include the free fall control as described above. That is, in this modification, deceleration control is executed from the start of work (time t1 in FIG. 5).

The impact force adjustment control calculation unit 114 executes deceleration control when the control state switching unit 112 switches the control state to the impact force adjustment state. In this deceleration control, the impact force adjustment control calculation unit 114 adjusts the braking force on the main winding drum DR1 so that the descending speed of the hammer grab 10 approaches the target speed Vs. The impact force adjustment control calculation unit 114 inputs a main winding brake command (command current value) to the main winding brake control proportional valve 62 so that the lowering speed of the hammer grab 10 approaches the target speed Vs, and the lowering speed of the hammer grab 10 approaches the target speed Vs. A braking force that approaches the speed Vs is generated in the main clutch brake 48. As a result, the descending speed of the hammer grab 10 is adjusted to the target speed Vs as shown in FIG. 5, and the descending speed when the hammer grab 10 falls to the landing position and lands on the bottom 12 of the hole becomes approximately the target speed Vs. Therefore, damage to the hammer grab 10 can be suppressed. On the other hand, if deceleration control as in the modified example is not performed, the hammer grab 10 will land on the bottom 12 at a high speed exceeding the target speed Vs, as shown by the broken line in FIG.

[Automatic brake control upon landing]
The automatic brake control upon landing is performed to control the main winding drum DR1 so that after the hammer grab 10 lands on the bottom 12 of the hole, the main winding wire rope R1 is prevented from being excessively paid out from the main winding drum DR1 (over-feeding). This is a control for adjusting the brakes. That is, the automatic brake control upon landing is a control for preventing excessive payout of the main winding wire rope R1 when the control state switching unit 112 determines that the hammer grab 10 has landed on the bottom 12 of the hole.

The control state switching unit 112 determines whether the hammer grab 10 has landed using, as a trigger (landing trigger), the satisfaction of a preset landing condition that allows determining that the hammer grab 10 has landed. Specifically, for example, the control state switching unit 112 determines the landing of the hammer grab 10 by comparing the origin set by the initial setting unit 110 and the hammer grab height calculated by the hammer grab height calculation unit 111. Good too. Further, the control state switching unit 112 may determine whether the hammer grab 10 has landed based on a change in the load value (rapid decrease in the load value) input from the load value detector 106 to the controller 101.

The control state switching unit 112 switches the control state from the impact force adjustment state to the landing automatic braking state when landing conditions are met, and the landing automatic braking control calculation unit 113 switches the main winding wire rope after the hammer grab 10 lands. In order to prevent over-feeding of R1, automatic brake control is executed upon landing to apply a brake on the rotation of main winding drum DR1. In this embodiment, in this automatic landing brake control, the automatic landing brake control calculation unit 113 operates the main winding clutch brake 48 to apply a full brake (maximum brake) to the rotation of the main winding drum DR1. May be controlled.

Specifically, when the control state is the automatic landing braking state, the spool of the mode switching valve 66 is placed in the proportional valve oil path forming position (the left position in FIG. 2), and the spool of the brake system switching valve 65 is placed in the braking position. The control proportional valve is arranged at the oil passage forming position (lower position in FIG. 2). When the control state is switched from the impact force adjustment state to the landing automatic braking state, the spool position of the mode switching valve 66 and the spool position of the brake system switching valve 65 remain in the same position as in the impact force adjustment state. maintained.

When the landing condition is satisfied when the hammer grab 10 reaches the landing position P3 in FIG. 1 and the control state is switched to the automatic landing brake state, the automatic landing brake control calculation unit 113 controls the A main winding brake command (command current value) that causes full braking to be applied is input to the main winding brake control proportional valve 62. As a result, a large braking force is generated in the main winding clutch brake 48 immediately after the hammer grab 10 lands on the bottom portion 12, and it is suppressed that the main winding wire rope R1 is unwound excessively from the main winding drum DR1. As a result, it is possible to prevent the main winding drum DR1 from continuing to rotate due to inertia after the hammer grab 10 lands. Therefore, during the subsequent winding of the main winding wire rope R1, disturbances in the winding state of the main winding wire rope R1 with respect to the main winding drum DR1 (so-called random winding) are suppressed.

[Loosen control]
The loosening control is used, for example, to loosen and soften the soil at the bottom 12 of a hole, thereby increasing the efficiency of subsequent excavation work (loosening work). In this loosening work, instead of dropping the hammer grab 10 from the work starting position P1 (high position) as in the excavation work, the hammer grab 10 is repeatedly dropped from a position relatively close to the bottom part 12 (low position). 12 soils are loosened.

The loosening control calculating section 115 (non-control calculating section 115) executes loosening control when the control state switching section 112 determines the control state to be the loosening control state (no control state). Specifically, when the control state is switched to the loosening control state (no control state), the loosening control calculation unit 115 (non-control calculation unit 115) moves the spool of the mode switching valve 66 to the proportional valve oil path forming position (Fig. A command to place the spool of the brake system switching valve 65 at the brake control proportional valve oil path forming position (the lower position in FIG. 2) is output to the mode switching valve 66. is output to the brake system switching valve 65.

Note that the control state switching unit 112 may set the loosening control state (no control state) as the initial setting of the control state. The control state switching unit 112 maintains the control state in the loosened control state (no control state) and does not change the control state to another control state until a predetermined reset operation is performed. The loosening control state (no control state) is a state in which automatic brake control such as impact force adjustment control is not performed.

The reset operation is an operation for updating the origin that serves as a reference for the height of the hammer grab 10. The operator causes the crane 200 to perform a reset operation by manually operating the main hoisting lever 51A. A specific example of the reset operation will be described later. After the reset operation is performed, the control state switching unit 112 switches from the loosening control state (no control state) to another state, for example, when the height of the hammer grab 10 exceeds a transition height that is a predetermined value. Switch to the control state. As another control state, an impact force adjustment state can be exemplified. This is because hammer grab work (excavation work) is often performed after loosening work.

The control state switching unit 112 changes the control state from the loosening control state (no control state) to the automatic landing state even when the above-mentioned landing conditions are met when the hammer grab 10 lands on the bottom 12 during loosening work. Switching to the braking state, the landing automatic brake control calculation unit 113 performs landing automatic brake control to brake the rotation of the main winding drum DR1 in order to prevent overfeeding of the main winding wire rope R1 after the hammer grab 10 lands. may be executed.

After the hammer grab 10 lands on the bottom 12, the operator performs a winding operation on the main winding lever 51A. Therefore, when the operator performs a hoisting operation while the control state is the automatic landing brake state, the control state switching unit 112 switches the control state from the automatic landing brake state to the loosening control state (no control state). You can. Thereby, the loosening work can be started smoothly after landing. However, the operator may perform a winding operation on the main winding lever 51A while the hammer grab 10 is falling. Therefore, when the operator performs a hoisting operation while the control state is in the impact force adjustment state or the automatic landing braking state, the control state switching unit 112 switches the control state to the loosening control state (no control state). Good too.

[Automatic brake invalidation control]
The automatic brake disabling control is designed to enable the operator to obtain the same operating feeling as the conventional operating feeling when the operator performs a brake operation (manual operation) on the main winding pedal 52A of the main winding brake operating device 52. It is control.

The control state switching unit 112 switches the control state to an automatic brake disabling control state when a preset disabling condition is satisfied. Specifically, for example, the invalidation condition may be that the temporary cancel switch 107 (see FIG. 3) is pressed. More specifically, the invalid condition is that the control state is an impact force adjustment state, a loosening control state (no control state), or an automatic brake control state upon landing, and either the main winding lever 51A or the auxiliary winding lever 53A is The temporary cancel switch 107 may be pressed when no operation is applied to the main winding pedal 52A and a brake operation is applied to the main winding pedal 52A.

The automatic brake invalidation control calculation unit 116 (brake control invalidation calculation unit 116) executes automatic brake invalidation control when the control state switching unit 112 determines the control state to be the automatic brake invalidation control state (brake control invalidation state). Specifically, when the control state is switched to the automatic brake invalidation control state, the automatic brake invalidation control calculation unit 116 places the spool of the mode switching valve 66 at the proportional valve oil path forming position (the left position in FIG. 2). A command for this is output to the mode switching valve 66, and the spool of the brake system switching valve 65 is placed at the pedal proportional valve oil path forming position (upper position in FIG. 2). Thereby, the main volume pedal proportional valve 67 can generate a braking force in the main volume clutch brake 48 according to the amount of operation of the main volume brake by the operator.

That is, the main volume pedal proportional valve 67 is connected to the oil chamber 43 of the main volume clutch brake 48 instead of the main volume brake control proportional valve 62 for automatically controlling the brake force. Therefore, when the operator performs a brake operation (manual operation) on the main winding pedal 52A of the main winding brake operating device 52, the braking force actually generated on the main winding drum DR1 is Since the magnitude corresponds to the operation amount of the main winding brake operation (pedal operation amount), the operator can obtain the same operation feeling as the conventional operation feeling.

FIG. 8 is a flowchart showing the calculation control operation performed by the controller 101 of the control device according to the present embodiment.

The control device according to the present embodiment performs control by switching the control state of the crane 200 to a control state corresponding to the stage of work performed by the crane 200. The control device may have a plurality of states for managing control in more detail within each of the plurality of control states, whereby the operation of the crane 200 is managed hierarchically.

The initial setting unit 110 of the controller 101 performs initial settings (step S1). Specifically, as described above, the initial setting unit 110 sets the load value detected by the load value detector 106 at the time when the operator presses the monitor switch 105 as the hammer grab weight, and sets the set hammer grab weight. Store the information in memory. Further, the hammer grab height calculation unit 111 sets the bottom 12 of the hole at that point in time in the work object (excavation object) as the origin. The origin is the height reference of the hammer grab 10 (step S1).

Next, as described above, the hammer grab height calculation unit 111 calculates the hammer grab height, which is the height of the hammer grab 10 at that point in time, using the bottom 12 of the hole at that point in the work object (excavation object) as the origin. (Step S2).

The control state switching unit 112 switches the control state using information such as the hammer grab height (step S3). As the initial state, the control state may be set to, for example, a loosening control state (no control state).

The control state switching unit 112 selects one of the plurality of control states using information such as the height of the hammer grab, the weight of the hammer grab, the main winding pedal input, the load value, and the input to the temporary cancel switch 107 (step S4).

When the control state switching unit 112 determines the control state to be the automatic landing brake state, the automatic landing brake control calculation unit 113 executes the automatic landing brake control as described above (step S5).

When the control state switching unit 112 determines the control state to be the impact force adjustment state, the impact force adjustment control calculation unit 114 executes the impact force adjustment control as described above (step S6).

When the control state switching unit 112 determines the control state to be the loosening control state (no control state), the loosening control calculating unit 115 (non-control calculating unit 115) executes the loosening control as described above (step S7).

When the control state switching unit 112 determines the control state to be the automatic brake invalid control state (brake control invalid state), the automatic brake invalid control calculation unit 116 (brake control invalid calculation unit 116) executes automatic brake invalid control (step S8).

The main volume brake control proportional valve command current value calculation unit 117 inputs the command current value to the main volume brake control proportional valve 62 based on the calculation result calculated by the calculation unit corresponding to the current control state among the calculation units 113 to 116. The main winding brake command (command current value) is calculated (step S9). Then, the main volume brake control proportional valve command current value calculation unit 117 inputs the calculated main volume brake command to the main volume brake control proportional valve 62 (step S10). Note that it is preferable to perform filter processing or the like on the command current value (brake input) calculated in each control state to prevent sudden changes in the current value.

The switching valve command current value calculation unit 118 calculates a command (command current value) to be input to the brake system switching valve 65 based on the calculation result calculated by the calculation unit corresponding to the current control state among the calculation units 113-116. ) and a command (command current value) to be input to the mode switching valve 66 (step S9). Then, the switching valve command current value calculation unit 118 inputs the calculated commands to the brake system switching valve 65 and the mode switching valve 66, respectively (step S10).

FIG. 9 is a flowchart showing a specific example of the impact force adjustment control (step S6 in FIG. 8) performed by the controller 101. The impact force adjustment control calculation unit 114 performs the above-described deceleration control when the deceleration control is in the ON state, and performs the above-described free fall control instead of the deceleration control when the deceleration control is in the OFF state.

First, when the control state switching section 112 switches the control state to the impact force adjustment state (impact force adjustment control ON: step S21), the hammer grab height calculation section 111 determines the bottom of the hole at that point in the work object (excavation object). 12 as the origin, the height of the hammer grab at that point is calculated (step S22).

Next, the impact force adjustment control calculation unit 114 determines whether the calculated hammer grab height is higher than the set height Hs (step S23). If the hammer grab height is higher than the set height Hs (YES in step S23), the impact force adjustment control calculation unit 114 performs free fall control to cause the hammer grab 10 to fall freely (step S25). On the other hand, if the hammer grab height is less than or equal to the set height Hs (NO in step S23), the impact force adjustment control calculation unit 114 applies a braking force to the main winding drum DR1 so that the descending speed of the hammer grab 10 approaches the target speed Vs. A deceleration control is performed to adjust the speed (step S24).

The control state switching unit 112 determines whether the landing condition is satisfied (step S26). If the landing conditions are satisfied (YES in step S26), the control state switching unit 112 switches the control state from the impact force adjustment state to the landing automatic braking state, and the controller 101 ends the impact force adjustment control and starts the landing. Automatic brake control is performed.

If the landing condition is not satisfied (NO in step S26), the controller 101 repeats steps S22-S26 described above.

FIG. 6 is a graph showing the relationship between the height position of the hammer grab 10 with respect to the bottom 12 of the hole in the work target and the load value. FIG. 6 shows a decrease in the load value when the hammer grab 10 lands, and an increase (rise) in the load value when the hammer grab 10 rises.

As described above, the hammer grab height is calculated using the amount of rotation of the main winding drum DR1 and the effective diameter (wound layer) of the main winding drum DR1. As shown in FIG. 6, the load value (hammer grab load) detected by the load value detector 106 shows that when the hammer grab 10 lands, the load of the hammer grab 10 is deposited on the ground compared to when the hammer grab 10 is falling. Therefore, it rapidly decreases to almost zero (time t3 in FIG. 6). Since the bottom portion 12 is excavated when the hammer grab 10 lands, the height position of the bottom portion 12 becomes lower than before the hammer grab 10 lands. Therefore, it is necessary to reset the height position of the bottom portion 12 every time excavation work is performed. That is, when the hole becomes deeper due to excavation work, it is necessary to update the origin according to the depth. The origin of the hammer grab height is reset based on the change in the load value when the hammer grab 10 leaves the bottom 12 (off the ground) as at time t4 in FIG. 6.

When the main winding wire rope R1 of the main winding drum DR1 is wound up after the hammer grab 10 lands, the hammer grab 10 rises while closing the grab 10B. During this winding process, when the hammer grab 10 separates from the bottom 12, the load of the hammer grab 10 is again applied to the main winding wire rope R1, and the load value increases at time t4 (the load value rises). The controller 101 resets the origin (height reset) by detecting the distance from the ground based on the rise of this load value. This series of operations is the above-mentioned reset operation.

Note that the height of the hammer grab cannot be reset until the hammer grab 10 lands for the first time, so at the time of the first excavation work, the operator should perform appropriate brake operations while landing the hammer grab 10 and reset the height to start the work. I can do it.

The hammer grab height calculation section 111 calculates the amount of rotation obtained from the main winding rotation sensor 81 of the drum rotation detector, the winding layer of the main winding drum calculated by the main winding drum winding layer calculating section 108, and main winding lever input detection. The above reset is performed using the main winding lever input input from the controller 101 from the load value detector 106, the load value input from the load value detector 106 to the controller 101, and the hammer grab weight set by the initial setting section 110. You may perform an action.

FIG. 7 is a graph showing the delay in the change in the load value measured by the load value detector 106 with respect to the actual change in the load value in the above reset operation.

There is a time delay between the time when the hammer grab 10 actually leaves the ground and the time when the load value indicating the separation is input to the controller 101 due to communication delays, sensor characteristics, etc. Sometimes. In this case, the rise of the load value at time t4 in FIG. 6 is detected with a delay, and when the rise of the load value is detected by the load value detector 106, the hammer grab 10 is already in the air. For this reason, if the hammer grab height is reset (initialized) as the origin at the rising timing of the load value, an error will occur between the reset origin and the actual height position of the bottom portion 12.

Therefore, in the present embodiment, the controller 101 receives the load change information regarding the load change input from the load value detector 106 and the load change information from the time when the hammer grab 10 leaves the bottom part 12 from the load value detector 106 to the controller 101. The height off the ground is determined using the delay time td (see FIG. 7) until input. That is, the controller 101 resets the height before the delay time as the bottom 12 (ground), taking into account the magnitude of the error caused by the delay time td.

Specifically, the controller 101 stores in advance an expected delay time as the delay time td. Before performing the reset operation, the operator may determine the delay time (estimated delay time) of the load value by estimating filter characteristics, communication delay characteristics, etc. in advance. Further, the expected delay time may be set, for example, by simulation before performing the reset operation, or may be set based on the actually measured delay time. Specifically, for example, the expected delay time may be determined by comparing the load value measured using a method with less delay on an actual crane and the load value measured using the load value detector 106. good.

When the controller 101 performs the reset operation, the controller 101 momentarily stores the hammer grab height from the time before the estimated delay time or a longer time. Then, the controller 101 calculates the difference between the height of the hammer grab before the expected delay time and the height of the hammer grab when the load value rises, and calculates the height when the corrected load value rises. As a result, the origin of the hammer grab height is reset (initialized). In order to use this method, the controller 101 may always store the hammer grab height for "(load value delay time)/(control period)".

A specific example will be explained as follows. Assume that the expected delay time (load value delay time) is set to, for example, 100 msec. In this case, it is assumed that the height of the hammer grab before resetting the origin (before initialization) is -300 mm 100 msec before the load value rises, and that the height of the hammer grab before initialization when the load rises is 500 mm. do. Since the delay is 100 msec, the moment 100 msec before the rise of the load value is the moment when true separation occurs. The fact that the height of the hammer grab before initialization is -300 mm 100 msec before the load value rises (the moment of true separation from the ground) means that this hammer grab excavated -300 mm of ground in one excavation. It means. Originally, it should be reset as the ground (0mm). However, since the height of the hammer grab before initialization when the load value rises is 500 mm, the hammer grab 10 has risen by a height of "500 mm - (-300 mm) = 800 mm" from the bottom when the load value rises. It turns out. Therefore, the origin of the hammer grab height is reset (initialized) taking into account that the hammer grab height is 800 mm when the load value rise is detected. Thereby, it is possible to suppress the brake from being driven before the hammer grab 10 collides with the bottom portion 12 (ground).

Next, an example of a method by which the controller 101 sets the set height Hs will be described. The set height Hs may be given in advance as a constant, but the controller 101 may determine the set height Hs using the target speed Vs and target acceleration (deceleration). Specifically, the controller 101 can determine the set height Hs using, for example, the following equation (1).

Here, in the above equation (1), "h _decSpeed " is the set height Hs. " _vo " is the current hammer grab speed. “v _conf ” is a preset speed upon landing (ie, the target speed Vs). “T _conf ” is the time to fall at a constant speed “v _conf ”. That is, "T _conf " is the time from when the hammer grab speed reaches the target speed Vs until the hammer grab lands. Moreover, "a _conf " is the magnitude of target acceleration (deceleration). "a _conf " may be determined using, for example, the hammer grab weight "W _hammar ", the maximum wire tension "P _confmax ", the gravitational acceleration "g", and the following equation (2).

The above equation (1) is obtained, for example, as follows. In the graph of FIG. 4, when deceleration control is started from time t2, it is assumed that the hammer grab speed at time t2 is decelerated at a constant acceleration (target acceleration a _conf ) from the target speed Vs. In this case, the target acceleration a _conf and the time T required to decelerate to the target speed Vs have the relationship expressed by the following equation (3).

The following equation (4) is obtained by transforming equation (3).

The height h _decSpeed required from time t2 when the deceleration control is started until the hammer grab lands on the bottom 12 of the hole can be expressed by the following equation (5).

By substituting the above equation (4) into the above equation (5), the following equation (6) is obtained.

In each of the above equations (5) and (6), "margin" can be set, for example, in consideration of the time T _conf (for example, 1 sec) for falling at a constant speed v _conf . Specifically, "margin" may be set to, for example, "v _conf ×T _conf ". By substituting this "margin" into the above equation (6), the above equation (1) is obtained.

As described above, the controller 101 determines the set height Hs using the target speed Vs and the target acceleration a _conf when the hammer grab 10 descends, so even if the operator is an unskilled person, An appropriate set height Hs is automatically set by the controller 101. In this case, the controller 101 can set the set height Hs as small as possible using the above formula that takes safety into consideration. Thereby, it becomes possible to set the distance over which the hammer grab 10 freely falls as long as possible, and the cycle time can be more effectively reduced. Specifically, acceleration (deceleration) is a parameter related to the difference from the target speed, impact during braking, and the like. Therefore, by determining the set height Hs using the target acceleration related to these, it is possible to safely make the hammer grab speed reach the target speed Vs without applying an excessively sudden brake during deceleration control.

The present disclosure is not limited to the embodiments described above. The present disclosure includes, for example, the following forms.

(A) Regarding crane specifications Although the crane according to the embodiment shown in FIG. 1 does not include a jib and a strut, the crane specifications are not limited to those shown in FIG. 1. The crane according to the present disclosure may be a luffing crane that includes a jib, a front strut, and a rear strut, or may be a fixed jib crane that includes a jib and one strut. Further, the crane according to the present disclosure may be a crane (for example, a large crane) that includes a mast instead of a gantry.

(B) Regarding the operating device The operating device according to the present disclosure may be appropriately selected depending on the type of the main winding winch and the auxiliary winding winch and the drive device thereof. For example, the main winding lever input detector 51B of the main winding winch operating device 51 and the auxiliary winding lever input detector 53B of the auxiliary winding winch operating device 53 shown in FIGS. It may be configured by a remote control valve that outputs pressure and a pressure sensor that detects secondary pressure of the remote control valve.

(C) Regarding the winch The main winch and the auxiliary winch according to the present disclosure may be, for example, electric winches. In this case, the hydraulic circuit shown in FIG. 1 can be replaced with an electric circuit (for example, a circuit including an inverter) that drives the electric winch.

(D) About the main winding and auxiliary winding In the embodiment described above, the body 10A of the hammer grab 10 and the grab 10B are suspended from the main winding wire rope R1 that is let out from the main winding drum DR1, but they are suspended from the main winding wire rope R1 that is let out from the auxiliary winding drum DR2. It may be suspended from the auxiliary winding wire rope R2. In this case, the crown 10C of the hammer grab 10 is suspended from the main winding wire rope R1. That is, the control device according to the present disclosure also includes a modification example in which the function of the component related to the "main volume" in the embodiment described above is performed by the component related to the "auxiliary volume."

(E) Regarding electric pedals The control device according to the embodiment shown in FIG. 2 includes a hydraulic circuit including a main volume pedal proportional valve 67 and a brake system switching valve 65. The brake system switching valve 65 generates a secondary pressure according to the amount of pedal operation input to the main winding pedal 52A of the winding brake operating device 52, and the brake system switching valve 65 is in a state where the brake control proportional valve oil passage is formed and when the pedal Switch between the state in which a proportional valve oil passage is formed. However, the control device according to the present disclosure is not limited to the embodiment described above, and may include a hydraulic circuit according to a modification example shown in FIG. 10, for example. In the control device for the crane 200 according to the modified example shown in FIG. 10, the main winding brake operating device 52 is constituted by a so-called electric pedal.

Specifically, as shown in FIG. 10, the main-volume brake operating device 52 includes a main-volume pedal 52A to which the main-volume brake operation by the operator is input, and an operation amount (pedal operation amount) of the input main-volume brake operation. ) for outputting a pedal operation signal to the controller 101. A pedal operation signal output from the output device 52B is input to the controller 101. Thereby, the controller 101 can acquire the pedal operation amount input to the main winding pedal 52A.

In the control device according to the modified example shown in FIG. It is adjusted based on the main winding brake command (command current value) inputted to the main winding brake control proportional valve 62 from the main winding brake control proportional valve 62 . In the control device according to the modification shown in FIG. 10, the main winding pedal proportional valve 67 and the brake system switching valve 65 included in the control device shown in FIG. 2 are omitted because they are unnecessary.

In this modification, the mode switching valve 66 is interposed between the main volume brake control proportional valve 62 and the main volume clutch brake 48. Specifically, the pilot pump 36, the main volume brake control proportional valve 62, the mode switching valve 66, and the oil chamber 43 of the main volume clutch brake 48 are connected in this order.

[Impact force adjustment control]
In this modification, when the control state is switched to the impact force adjustment state, the impact force adjustment control calculation unit 114 positions the spool of the mode switching valve 66 at the proportional valve oil path forming position (the left position in FIG. 2). This command is output to the mode switching valve 66. As a result, the main winding clutch brake 48 is switched to the free state, and the hammer grab 10 becomes in a state where it can freely fall due to its own weight. Further, the impact force adjustment control calculation unit 114 applies a brake force to the main volume clutch brake 48 according to the main volume brake command (command current value) input from the impact force adjustment control calculation unit 114 to the main volume brake control proportional valve 62. can be generated in

[Automatic brake control upon landing]
In addition, in this modification, when the control state is switched to the landing automatic braking state, the landing automatic braking control calculation unit 113 moves the spool of the mode switching valve 66 to the proportional valve oil path forming position (left side position in FIG. 2). A command for arranging the mode is output to the mode switching valve 66. Then, the landing automatic brake control calculation unit 113 inputs a main winding brake command (command current value) to the main winding brake control proportional valve 62 so that a full brake is applied to the rotation of the main winding drum DR1. As a result, a large braking force is generated in the main winding clutch brake 48 immediately after the hammer grab 10 lands on the bottom portion 12, and it is suppressed that the main winding wire rope R1 is unwound excessively from the main winding drum DR1.

[Loosen control]
Further, in this modification, when the control state is switched to the loosening control state, the loosening control calculation unit 115 performs a control operation for arranging the spool of the mode switching valve 66 at the proportional valve oil path forming position (left side position in FIG. 2). A command is output to the mode switching valve 66.

[Automatic brake invalidation control]
Further, in this modification, when the control state is switched to the automatic brake invalidation control state, the automatic brake invalidation control calculation unit 116 moves the spool of the mode switching valve 66 to the proportional valve oil path forming position (the left position in FIG. 2). A command for placement is output to the mode switching valve 66. Then, the automatic brake invalidation control calculation unit 116 generates a main volume brake command (command current value) so that a brake force corresponding to the operation amount (pedal operation amount) of the main volume brake operation by the operator is generated at the main volume clutch brake 48. is input to the main winding brake control proportional valve 62.

Note that the other configurations of the control device according to the modification shown in FIG. 10 are the same as the configuration of the control device according to the embodiment shown in FIG. 2, so detailed explanations will be omitted. Further, when the auxiliary brake operating device 54 is constituted by an electric pedal, the auxiliary brake operating device 54 includes an auxiliary pedal 54A and an output device 54B, and the hydraulic circuit including the auxiliary brake operating device 54 is The configuration is similar to the configuration of the hydraulic circuit as described above including the main brake operating device 52 related to the electric pedal, so a detailed explanation thereof will be omitted.

10: Hammer grab 11: Casing 12: Bottom (bottom of work target)
48: Main winding clutch brake 51: Main winding winch operating device 51A: Main winding lever 51B: Main winding lever input detector 52: Main winding brake operating device 52A: Main winding pedal 52B: Output device 62: Main winding brake control proportional valve 65: Brake system switching valve 66: Mode switching valve 67: Main winding pedal proportional valve 81: Main winding rotation sensor (drum rotation detector)
91: Setting input device 92: Start instruction input device 100: Crane 101: Controller 105: Monitor switch 106: Load value detector 200: Crane DR1: Main hoisting drum Hs: Setting height P1: Work start position P2: Start of deceleration control Position P3: Landing position R1: Main winding wire rope Vs: Target speed WC1: Main winding winch

Claims (9)

A control device for construction machinery that performs hammer grab work by dropping a hammer grab by letting out a wire rope from a winch drum,
a detector used to obtain a hammer grab height that is the height of the hammer grab from the bottom of the work target of the hammer grab operation;
When the height of the hammer grab is higher than a set height set above the bottom, the hammer grab is allowed to fall freely, and when the height of the hammer grab is less than the set height, the descending speed of the hammer grab is set at a predetermined speed. A controller for controlling a brake on the winch drum so as to approach a target speed of the winch drum. 2. The controller according to claim 1, wherein the controller performs control to adjust a brake on the winch drum so that the wire rope is prevented from being excessively paid out from the winch drum after the hammer grab lands on the bottom. Control equipment for construction machinery. further comprising an input device for receiving input of the set height by an operator,
The control device for construction machinery according to claim 1 or 2, wherein the controller sets the set height based on the input. The control device for a construction machine according to claim 1 or 2, wherein the controller determines the set height using the target speed and a target acceleration when the hammer grab descends. further comprising a load value detector that detects a hammer grab load that is a load of the hammer grab acting on the wire rope,
The controller controls the height when the hammer grab separates from the bottom based on a load change in which the hammer grab load increases as the wire rope is wound up by the winch drum from a state where the hammer grab is in contact with the bottom. 2. The control device for a construction machine according to claim 1, wherein a height off the ground that is a position is determined, and the height of the hammer grab is calculated using the height off the ground as an origin. The controller includes load change information regarding the load change that is input from the load value detector, and information from the time when the hammer grab leaves the bottom until the load change information is input from the load value detector to the controller. The control device for a construction machine according to claim 5, wherein the ground clearance height is determined using a delay time. 2. The control device for a construction machine according to claim 1, wherein the controller performs loosening control for performing loosening work when the operator performs a hoisting operation after the hammer grab lands on the bottom. A control device according to claim 1;
A construction machine comprising the winch drum. A control method for a construction machine that performs hammer grab work by dropping a hammer grab by letting out a wire rope from a winch drum, the method comprising:
obtaining a hammer grab height that is the height of the hammer grab from the bottom of the work target of the hammer grab work;
When the height of the hammer grab is higher than a set height set above the bottom, the hammer grab is allowed to fall freely, and when the height of the hammer grab is less than the set height, the descending speed of the hammer grab is set at a predetermined speed. adjusting a brake on the winch drum so as to approach a target speed of the winch drum.