JP5725531B2 - Winch control device and mobile crane - Google Patents

Description

  The present invention relates to a winch control device and a mobile crane.

  2. Description of the Related Art Conventionally, a winch control device using a variable displacement winch motor that can switch the number of revolutions with respect to the amount of supplied oil to a low speed mode or a high speed mode by switching the capacity per rotation is known.

  For example, Patent Document 1 includes an overload prevention device, an operation detection unit, a mode selection unit, and a motor capacity switching unit, and stores the load immediately before the start of unwinding to determine the condition for switching to the high speed mode. A control device that prevents hunting caused by fluctuations in the load value during winding is disclosed.

  Further, Patent Document 2 includes an operation amount detection unit and a capacity switching restriction unit. If the operation amount is equal to or less than a predetermined amount, the switching to the small capacity side (high speed mode) is disabled, thereby driving. A control device that avoids inability to start due to insufficient torque is disclosed.

JP 2002-68667 A JP 2002-87762 A

  However, the control device of the above-described patent document controls the winch based on either the load or the operation amount, and does not control the winch based on both the load and the operation amount.

  Therefore, the present invention provides a winch control device that balances safety and operability by controlling the winch in consideration of both the load and the operation amount, and a mobile crane including the winch control device. It is intended to provide.

In order to achieve the above object, a winch control device according to the present invention is a winch control device for controlling the rotation speed of a winch, comprising: a load detection means for detecting a load of a suspended load; A variable displacement winch motor that is rotationally driven in a high-speed mode, winch operation means for operating the variable displacement winch motor, and the variable displacement winch motor based on the load of the suspended load and the operation amount of the winch operation means. A control unit that switches to a low speed mode or a high speed mode, and the control unit controls the variable capacity winch motor regardless of the load of the suspended load when the operation amount is less than a predetermined switching operation amount. It is characterized that you keep the low-speed mode.

  Thus, the winch control device of the present invention includes a load detecting means, a variable capacity winch motor, a winch operating means, and a variable capacity winch motor based on the load of the suspended load and the operation amount of the winch operating means. And a control unit for switching to the low speed mode or the high speed mode.

  For this reason, by considering both the load of the suspended load detected by the load detection means and the operation amount of the winch operation means based on the operator's intention, the safety when the load is large and the operation amount when the operation amount is small Fine movement operability can be harmonized.

It is a side view explaining the structure of the whole cargo crane. It is a hydraulic circuit diagram explaining the structure of a hydraulic system. FIG. 3 is a block diagram illustrating a configuration of a control unit according to the first embodiment. It is explanatory drawing explaining the control content of Example 1. FIG. 3 is a graph illustrating the operation of Example 1. FIG. 5 is a block diagram illustrating a configuration of a control system according to a second embodiment. It is explanatory drawing explaining the control content of Example 2 when the load of a hanging load is larger than a switching load. It is explanatory drawing explaining the control content of Example 2 when the load of a hanging load is smaller than a switching load.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Mechanical structure)
First, the overall configuration of the mechanical system of a cargo crane 1 as a mobile crane provided with the winch control device 2 (see FIG. 2) of the present embodiment will be described with reference to FIG.

  A cargo crane 1 according to the present embodiment is supported by a vehicle body 10 having a traveling function, an outrigger 11 that prevents the vehicle body 10 from falling, a post 12 that is slidably provided on the vehicle body 10, and a post 12 that can be raised and lowered. A boom 13, a hoisting cylinder 14 for raising and lowering the boom 13, a hook 16 suspended from the tip of the boom 13 via a wire 15, a loading platform 17 for loading loads, and an operating cabin 18. .

  A winch 48 and a speed reducer 47 are disposed inside the post 12, and the wire 15 can be wound or fed out by the rotation of the variable displacement winch motor 44 (see FIG. 2).

  In addition, the boom 13 includes a first boom 131 whose base end portion is supported by the post 12 so as to be raised and lowered, a second boom 132 inserted into the first boom 131, a third boom 133 inserted into the second boom 132, Is configured in a nested manner.

(Hydraulic system configuration)
Next, the configuration of the hydraulic circuit including the winch control device 2 of this embodiment will be described with reference to FIG.

  The hydraulic circuit including the winch control device 2 of the present embodiment includes a hydraulic pump 41, a relief valve 42, a directional flow control valve 43, a variable displacement winch motor 44, a switching valve 45, and a tilt angle control cylinder. 46, a speed reducer 47, and a winch 48.

  This directional flow control valve 43 is a 6-port manual switching valve. When the operator manually operates an operation lever 49 as a winch operation means, the direction and flow rate of the hydraulic oil are adjusted in proportion to the operation amount. To the variable capacity winch motor 44. In addition, a differential transformer 54 is attached to the directional flow control valve 43 as an operation amount detector that detects the spool position.

  The variable displacement winch motor 44 is a swash plate type or swash axis type axial piston motor, and rotates in a low speed mode or a high speed mode according to an instruction from the controller 3. Specifically, when the switching valve 45 that has been instructed by the controller 3 is switched to the OFF position, the pressure oil in the tilt angle control cylinder 46 is released and the internal spring moves to the large capacity position (low speed mode). Become. On the other hand, when the switching valve 45 is switched to the ON position, the drive pressure of the variable displacement winch motor 44 is supplied to the tilt angle control cylinder 46 via the shuttle valve to enter the small displacement position (high speed mode). .

  Furthermore, a boom length detector 51 that detects the entire length of the boom 13 and a boom angle detector 52 that detects the angle of the boom 13 are attached to the first boom 131 of the present embodiment. In addition, the undulating cylinder 14 is provided with a moment detector 53 that detects a moment load by measuring a pressure difference between the rod side and the cylinder side.

  Then, the detected values of the boom length detector 51, the boom angle detector 52, and the moment detector 53 as the load detecting means 5, and the operation amount detected by the differential transformer 54 as the operation amount detector. The received controller 3 determines either the low speed mode or the high speed mode, and instructs the switching valve 45 to turn off or on.

(Configuration of control unit)
Next, the configuration of the controller 3 as the control unit of the winch control device 2 of the present embodiment will be described with reference to FIGS.

  The controller 3 as the control unit of the present embodiment is a general-purpose microcomputer, and includes a load calculation unit 31, a load determination unit 32, a switching load storage unit 33, a position determination unit 34, and a switching position storage unit 35. The mode determination unit 36 and the output unit 37 are provided.

  The load calculating unit 31 stores the boom length L detected by the boom length detector 51, the boom angle θ detected by the boom angle detector 52, the moment M detected by the moment detector 53, and the like. Based on the weight of the hook 16 or the like, the load W of the suspended load is calculated in reverse calculation.

  The load determination unit 32 determines the magnitude relationship between the switching load WX stored in the switching load storage unit 33 and the calculated load W of the suspended load. Here, the switching load WX is determined so that a sufficient torque can be obtained even in the high-speed mode in consideration of the lifting ability (torque). Specifically, when the maximum crane capacity is 2.93 (t) × 4.0 (m), the switching load WX is set to 1.7 (t).

  The position determination unit 34 indirectly determines the operation amount S of the operation lever 49 based on the spool position P of the directional flow control valve 43 detected by the differential transformer 54. That is, the position determination unit 34 determines the magnitude relationship between the switching position PX stored in the switching position storage unit 35 and the detected spool position P. Here, the switching position PX is determined so that the fine movement area can be secured while suppressing the shock in consideration of the impact due to the speed difference when switching between the high speed mode and the low speed mode and the size of the fine movement operation area. Specifically, when the entire stroke of the spool is 6.3 (mm), the switching position PX is set to 4.0 (mm).

  The mode determination unit 36 applies the determination map (FIG. 4) based on the determination result of the load W of the suspended load and the determination result of the spool position P, and instructs either the low speed mode or the high speed mode. To determine.

  That is, as shown in FIG. 4, the vertical axis (y-axis) is the load W of the suspended load, the horizontal axis (x-axis) is the spool position P, and the switching load WX and the switching position PX are the boundaries as a whole. In the determination map divided into two, it is determined to which region the state (P, W) at the time of determination belongs.

  In short, since the mode determination unit 36 is considered to have an intention to finely control when the spool position P is less than the switching position PX, the low-speed mode regardless of the magnitude of the load W and the switching load WX. Is determined.

  On the other hand, when the spool position P is equal to or higher than the switching position PX, the mode determination unit 36 is considered to have a desire to move at a high speed. Therefore, the mode determination unit 36 should be applied depending on the magnitude relationship between the suspended load W and the switching load WX. Change the mode. That is, if the load W of the suspended load is less than the switching load WX, the intention of high-speed movement is given priority and the high-speed mode is determined. If the load W of the suspended load is greater than or equal to the switching load WX, priority is given to safety. Judged as low speed mode.

(Function)
Next, the operation of the winch control device 2 of the present embodiment will be described with reference to FIGS. Here, the operation amounts S0 to S1 in FIG. 5 are at the spool position 0 in FIG. 4, the operation amount S3 in FIG. 5 is the full stroke 6.3 (mm) in FIG. 4, and the switching operation amount SX in FIG. It corresponds to each position PX (= 4.0 (mm)).

(Improved operability when the amount of operation is small)
First, a case where the operation amount S of the operation lever 49 as the winch operation means is less than the switching operation amount SX regardless of the load W of the suspended load will be described.

  In this case, since it is presumed that the worker has an intention to perform a fine movement operation, this intention is prioritized and the low-speed mode is maintained.

  Specifically, if the load W of the suspended load is greater than or equal to the switching load WX, the state changes to abbeg in FIG. That is, it changes to ab before the grounding of the suspended load, and apparently after the grounding, the load W of the suspended load becomes light and changes to beg. The states (P, W) at the time of determination are always in the low speed mode because both states are in the low speed mode.

  When this state is described with reference to FIG. 5, it corresponds to the state changing between A and Y, and the low speed mode is always set.

  Similarly, if the load W of the suspended load is less than the switching load WX, the state changes to deg in FIG. That is, before the grounding of the suspended load, it changes to de, and after the grounding, the load W of the suspended load becomes lighter and changes to eg. The states (P, W) at the time of determination are always in the low speed mode because both states are in the low speed mode.

  When this state is described with reference to FIG. 5, it corresponds to the state changing between A and Y, and the low speed mode is always set.

(Speeding up when the amount of operation is large and the load is small)
Next, a case where the operation amount S of the operation lever 49 as the winch operation means is greater than or equal to the switching operation amount SX and the load W of the suspended load is smaller than the switching load WX will be described.

  In this case, since it is presumed that the operator has no intention to perform a fine movement operation and desires to move at high speed, this intention is prioritized and the high speed mode is set.

  Specifically, if the load W of the suspended load is less than the switching load WX, the state changes to dfh in FIG. That is, before the grounding of the suspended load, it changes to df, and after the grounding, the load W of the suspended load becomes lighter and changes to fh. In the state of ef where the spool position is PX or more, the low speed mode is switched to the high speed mode.

  When this state is described with reference to FIG. 5, for example, it corresponds to the state being changed to AYZD, and when the operation amount S reaches the switching operation amount SX, the low speed mode is changed to the high speed mode. (YZ), the suspension is lowered in the high speed mode to ground the suspended load, and the high speed mode is maintained even after the ground contact.

(Improved safety when the amount of operation is large and the load is large)
Next, a case where the operation amount S of the operation lever 49 as the winch operation means is greater than or equal to the switching operation amount SX and the load W of the suspended load is greater than the switching load WX will be described.

  In this case, although it is presumed that the operator does not intend to perform a fine movement operation and intends to move at high speed, safety is given priority because the load W of the suspended load is large, and the low speed mode is set as a general rule.

  Specifically, if the load W of the suspended load is greater than or equal to the switching load WX, the state changes to abcffh in FIG. In other words, the load changes from a to b-c before contact with the suspended load, and apparently after the contact, the load W of the suspended load becomes lighter and changes to cfh. Change. That is, after the suspended load is grounded, the low speed mode is switched to the high speed mode.

  When this state is described with reference to FIG. 5, for example, this corresponds to a change in the state of AYBD, and the low speed mode is maintained during the stroke (AYB), but the low speed mode is maintained. After lowering and the suspended load is grounded, the mode is switched from the low speed mode to the high speed mode (BD).

  As described above, when switching from the low speed mode to the high speed mode at the time of grounding (cf in FIG. 4), the operator may return the operation lever 49 to reduce the operation amount S, although safety may be impaired. By doing so (fe, fg in FIG. 4), it is possible to return from the high speed mode to the low speed mode. Here, a countermeasure for safety will be described later as a second embodiment.

(effect)
Next, effects of the winch control device 2 of this embodiment will be listed and described.

  (1) Thus, the winch control device 2 of the present embodiment is a winch control device 2 for controlling the rotational speed of the winch 48, and is a boom length as load detection means for detecting the load W of the suspended load. As a height detector 51, a boom angle detector 52, a moment detector 53, a variable capacity winch motor 44 that rotates the winch 48 in a low speed mode or a high speed mode, and winch operation means for operating the variable capacity winch motor 44 And the controller 3 as a control unit that switches the variable capacity winch motor 44 to the low speed mode or the high speed mode based on the load W of the suspended load and the operation amount S of the operation lever 49.

  Therefore, the spool position P proportional to the load W of the suspended load detected by the boom length detector 51, the boom angle detector 52, and the moment detector 53 and the operation amount S of the operation lever 49 based on the operator's intention. By determining the mode in consideration of both, safety and operability can be harmonized.

  That is, if the mode is determined based only on the load W of the suspended load with priority given to safety, even if the operation amount S is decreased when the load W of the suspended load is small, the fine movement operation in the low speed mode cannot be performed. Becomes worse.

  On the other hand, if the mode is determined based only on the operation amount S with priority on operability, even if the load W of the suspended load is large, if the operation amount S is large, high-speed movement in the high-speed mode is possible and there is a possibility that safety is impaired. .

  Therefore, by preparing a determination map based on both the load W of the suspended load and the operation amount S, and determining the mode by fitting to the determination map, the operability and the safety can be harmonized.

  (2) Further, when the operation amount S is less than the predetermined switching operation amount SX, the controller 3 as the control unit maintains the variable displacement winch motor 44 in the low speed mode regardless of the load W of the suspended load. .

  As described above, when the operation amount S is small, priority is given to the operator's intention to work carefully, and the variable displacement winch motor 44 is maintained in the low speed mode, thereby enabling fine movement operation.

  (3) Further, the controller 3 as the control unit, when the operation amount S is equal to or greater than the predetermined switching operation amount SX, if the load W of the suspended load is less than the predetermined switching load WX, the variable capacity winch motor 44. Is set to the high speed mode, and the variable capacity winch motor 44 is set to the low speed mode if the load W of the suspended load is equal to or greater than the switching load WX.

  As described above, when the operation amount S is large, safety can be improved by determining the low speed mode or the high speed mode according to the load W of the suspended load while giving priority to the operator's intention to move at high speed. .

  (4) And the cargo crane 1 as a mobile crane of a present Example becomes a crane which harmonized safety and operativity by providing the control apparatus 2 of one of the winches mentioned above.

  Hereinafter, a winch control device 2A different from the above-described embodiment will be described with reference to FIGS. The description of the same or equivalent parts as described in the above embodiment will be given with the same reference numerals.

(Constitution)
Since the configuration of the mechanical system and the configuration of the hydraulic system of the winch control device 2A of the present embodiment are the same as those of the first embodiment, description thereof will be omitted.

(Configuration of control unit)
Next, the configuration of the controller 3A as the control unit of the winch control device 2A according to the present embodiment will be described with reference to FIG.

  The controller 3A as the control unit of the present embodiment includes a load calculation unit 31, a load determination unit 32, a switching load storage unit 33, a position determination unit 34, a switching position storage unit 35, a mode determination unit 36, In addition to the output unit 37, a lowering determination unit 61, a neutral determination unit 62, and a mode storage unit 63 are further provided.

  The unwinding determination unit 61 determines the start of unwinding based on the time change of the spool position P corresponding to the operation amount S of the operation lever 49. Specifically, the time point when the spool position P exceeds zero from the winding upper side and the position is changed to the lowering side is determined as the winding start time.

  Similarly, the neutral determination unit 62 determines neutral based on the temporal change of the spool position P corresponding to the operation amount S of the operation lever 49. Specifically, the time when the spool position P becomes zero from the lower position is determined to be neutral.

  Further, the mode storage unit 63 stores the mode determination result of the mode determination unit 36 at the time when the lowering determination unit 61 determines that the lowering is started. In short, it memorizes whether the low-speed mode or the high-speed mode was set at the start of the lowering.

  And the mode determination part 36 of a present Example selects a determination map at the time of winding-down start, determines low speed mode or high speed mode by fitting to the selected determination map, and uses the same determination map until neutral time Apply.

  That is, first, the mode determination unit 36 selects which determination map of the two prepared determination maps should be applied according to the load W of the suspended load at the start of unwinding. Specifically, the determination map of FIG. 7 is applied if the load W of the suspended load is greater than or equal to the switching load WX, and the determination map of FIG. 8 is applied if the load W of the suspended load is less than the switching load WX.

  Next, the mode determination unit 36 applies the selected determination map (FIG. 7 or FIG. 8) to the low speed mode based on the determination result of the suspended load W and the determination result of the spool position P. Alternatively, it is determined which one of the high-speed modes is instructed.

  Thereafter, the mode determination unit 36 continues to apply the selected determination map until the neutral time, selects the determination map to be applied again when the neutral time is reached, and again applies the determination map to the determination map.

(Function)
Next, the operation of the winch control device 2A of this embodiment will be described.

(Improved operability when the load at the start of unwinding is large)
First, the case where the load W of the suspended load at the start of unwinding is greater than or equal to the switching load WX will be described.

  In this case, safety is prioritized regardless of the amount of operation S, and the low speed mode is maintained until the operation lever 49 is neutral.

  Specifically, if the load W of the suspended load at the start of unwinding is equal to or greater than the switching load WX, the mode determination unit 36 performs the fitting after applying the determination map of FIG.

  If the operation amount S is large, the state changes to, for example, abcfch in FIG. That is, before the grounding of the suspended load, it changes to abc, and after the grounding, the load W of the suspended load becomes lighter and changes to cfh. In the determination map of FIG. 7, since the low speed mode is set in all areas, the low speed mode is maintained.

  On the other hand, if the operation amount S is small, the state changes to, for example, abeg in FIG. That is, it changes to ab before the grounding of the suspended load, and apparently after the grounding, the load W of the suspended load becomes light and changes to beg. In the determination map of FIG. 7, since the low speed mode is set in all areas, the low speed mode is maintained.

  If this state is described with reference to FIG. 5, it corresponds to the state changing between AYB (-C), and the low speed mode is always set.

(Speeding up when the load at the start of unwinding is small)
Next, the case where the load W of the suspended load at the start of unwinding is less than the switching load WX will be described.

  In this case, until the operation lever 49 is neutral, the high speed mode is set if the operation amount S is large, and the low speed mode is set if the operation amount S is small.

  Specifically, if the load W of the suspended load at the start of unwinding is less than the switching load WX, the mode determination unit 36 applies the determination after applying the determination map of FIG.

  If the operation amount S is large, the state changes to, for example, dfh in FIG. That is, before the grounding of the suspended load, it changes to df, and after the grounding, the load W of the suspended load becomes lighter and changes to fh. In ef, since the spool position exceeds PX and the high speed mode is set, the low speed mode is switched to the high speed mode.

  On the other hand, if the operation amount S is small, the state changes to eg deg in FIG. That is, before the grounding of the suspended load, it changes to de, and after the grounding, the load W of the suspended load becomes lighter and changes to eg. Since deg is a low speed mode, the low speed mode is maintained.

  When this state is described with reference to FIG. 5, it corresponds to the state changing between AYZD (-E), and when the operation amount S reaches the switching operation amount SX, the low speed mode is changed to the high speed state. Switch to mode (Y-Z).

(effect)
Next, effects of the winch control device 2A of this embodiment will be listed and described.

  (1) As described above, the controller 3A as the control unit of the winch control device 2A of the present embodiment, when the load W of the suspended load at the time when the lowering is started is equal to or higher than the predetermined switching load WX. The variable displacement winch motor 44 is maintained in the low speed mode until the operation lever 49 as the winch operation means is neutral.

  For this reason, when the load W of the suspended load is large, it is possible to prevent the switching to the high-speed mode even if the apparent load becomes light after the grounding by maintaining the low-speed mode, thereby improving the safety.

  (2) Further, the controller 3A as the control unit makes the operation lever 49 as the winch operation means neutral when the load W of the suspended load at the time when the lowering is started is less than the predetermined switching load WX. Until the operation amount S is less than the predetermined switching operation amount SX, the variable displacement winch motor 44 is set to the low speed mode, and when the operation amount S is greater than or equal to the switching operation amount SX, the variable displacement winch motor 44 is set to the high speed mode. To.

  For this reason, when the load W of the suspended load is small, the operator's intention reflected in the operation amount S is prioritized. When the operation amount S is small, the low-speed mode is set, and when the operation amount S is large, the high-speed operation is performed. Operability can be improved by setting the mode.

  In addition, since it is as substantially the same as the said Example about another structure and an effect, description is abbreviate | omitted.

  The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention are not limited to the present invention. included.

  For example, in the first and second embodiments, the case where the winch control devices 2 and 2A are applied to the cargo crane 1 as a mobile crane is described. However, the present invention is not limited to this, and a truck crane, a rough terrain crane, It can also be applied to mobile cranes such as all-terrain cranes.

  In the first and second embodiments, the case where the spool position P is detected in order to indirectly detect the operation amount S has been described. However, the present invention is not limited to this, and a radio control device ( When the transmitter / receiver is used, the operation amount S can be detected directly without detecting the spool position P.

  Further, the first embodiment has been described by taking the lowering as an example. However, the present invention is not limited to this, and the determination map of FIG. 4 can be applied not only to the lowering but also to the hoisting.

  In the first and second embodiments, the switching load WX and the switching position PX are described as being stored in the switching load storage unit 33 and the switching position storage unit 35 in advance. However, the present invention is not limited to this. The value can be adjusted to an appropriate value according to the user's preference.

  In addition, although the second embodiment has been described as having the controller 3A different from the first embodiment, it is not limited to this, and the controller 3A of the second embodiment is the same as the controller 3 of the first embodiment. However, the second embodiment may be implemented exceptionally after the first embodiment is used as a principle.

  Furthermore, in the said Example, although the load calculating part 31 demonstrated the case where the load W of a suspended load was calculated based on boom length L, boom angle (theta), moment M, etc., it is not limited to this. Alternatively, the speed of the variable capacity winch motor 44 may be controlled by determining the load W of the suspended load based on the pressure supplied to the variable capacity winch motor 44.

  As a configuration in that case, the winch control device includes a pressure switch in the hydraulic path of the directional flow control valve 43 and the variable displacement winch motor 44. This pressure switch outputs a signal when the crane lifts the load W of the suspended load corresponding to the switching load WX. If this signal is input to the controller 3, winch control similar to that in the above embodiment can be performed.

  That is, the controller 3 receives a signal from the pressure switch, performs signal conversion processing inside the controller 3, and outputs a signal to the hanging mode determination unit 32.

  Note that the pressure detected by the pressure switch when the load W of the suspended load is lifted varies depending on the capacity of the variable displacement winch motor 44. In order to cope with this change, two types of pressure switches according to the size of the capacity are provided, and the output of the pressure switch to be used is selected according to the current capacity of the variable capacity winch motor 44. Good. Since the controller 3 stores the current capacity of the variable displacement winch motor 44, the selection can be performed by processing inside the controller 3. Therefore, the appropriate one selected from the outputs of the two pressure switches is selected. What is necessary is just to output an output to a hanging load mode determination part.

  Accordingly, the speed control of the variable displacement winch motor 44 can be performed without providing a sensor for detecting the boom length L, the boom angle θ, and the moment M, and the configuration can be simplified.

P Spool position PX Switching position S Operation amount SX Switching operation amount W Suspended load WX Switching load 1 Cargo crane (movable crane)
2,2A winch controller 3,3A controller (control unit)
31 load calculation unit 32 load determination unit 33 switching load storage unit 34 position determination unit 35 switching position storage unit 36 mode determination unit 37 output unit 43 directional flow control valve 44 variable displacement winch motor 51 boom length detector (load detection means) )
52 Boom angle detector (load detection means)
53 Moment detector (load detection means)
54 Differential transformer (Operation amount detector)
61 Lowering determination unit 62 Neutral determination unit 63 Mode storage unit

Claims (5)

A winch control device for controlling the rotation speed of the winch,
Load detection means for detecting the load of the suspended load;
A variable displacement winch motor that rotationally drives the winch in a low speed mode or a high speed mode;
Winch operating means for operating the variable capacity winch motor;
A control unit that switches the variable capacity winch motor to a low speed mode or a high speed mode based on the load of the suspended load and the operation amount of the winch operating means ,
Wherein, when the operation amount is smaller than the predetermined switching operation amount, regardless of the load of the suspended load, control of the winch, characterized that you keep the variable displacement winch motor to the low speed mode apparatus. When the operation amount is equal to or greater than a predetermined switching operation amount, the control unit
The variable capacity winch motor is set to a high speed mode if the load of the suspended load is less than a predetermined switching load, and the variable capacity winch motor is set to a low speed mode if the load of the suspended load is equal to or higher than the switching load. The winch control device according to claim 1 . In the case where the load of the suspended load at the time when the lowering is started is equal to or higher than a predetermined switching load, the control unit is configured to neutralize the winch operation means.
The winch control device according to claim 1 or 2, wherein the variable displacement winch motor is maintained in a low speed mode. In the case where the load of the suspended load at the time when the lowering is started is less than a predetermined switching load, the control unit, until the winch operation means is neutral,
The variable displacement winch motor is set to a low speed mode if the operation amount is less than a predetermined switching operation amount, and the variable displacement winch motor is set to a high speed mode if the operation amount is greater than or equal to the switching operation amount. The winch control device according to any one of claims 1 to 3 . A mobile crane comprising the winch control device according to any one of claims 1 to 4 .