JP2788614B2 - Crane boom undulation control method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling a boom hoisting drive in a crane.

[0002]

2. Description of the Related Art Generally, in a crane in which a boom is driven up and down, a rated total load corresponding to the capacity of the crane is set in order to prevent overturning and damage to a machine. Since the rated total load decreases as the working radius increases, the ratio of the actual load to the rated total load (load ratio) changes as the boom moves up and down. Therefore, it is important to monitor the load factor during the operation of raising and lowering the boom and stop the boom raising and lowering drive before the load factor exceeds the upper limit (for example, 100%). If the operator constantly monitors the rate, the burden becomes very large. Therefore, such a crane is generally provided with a control device that automatically stops the boom when the load factor reaches the upper limit during driving of the boom.

When such an automatic stop is performed, it is desirable for safety to sufficiently lower the boom hoisting speed before the stop. Therefore, as a control device for decelerating before stopping the up and down movement of the boom, for example, Japanese Utility Model Laid-Open No. 5-69069.
In the micro-film, a first value η ₁ lower than the upper limit is set in advance for the load factor η, and the relationship between the load factor η and the actual pump discharge amount Q as shown in the graph of FIG. Is set, and based on this relationship, the pump discharge amount Q is changed according to the change of the load factor η.

According to this device, at the time of boom fall when the load factor η increases, the pump discharge amount Q starts to be reduced (ie, deceleration starts) when the load factor η _first reaches the _first load factor η _1. ), And when the load factor reaches 100%,
The pump discharge amount Q is reduced to the minimum value, the control valve is returned to the neutral position, and the winch drive is forcibly stopped.

[0005]

In the above apparatus, the first value η ₁ for starting deceleration is constant regardless of the boom up / down driving state, and in any case, the load factor η is equal to the first value η.
Whenever the speed reaches ₁ , deceleration starts. Accordingly, even if not yet required deceleration is boom fallen speed is sufficiently low, the load factor eta is the decelerated when it reaches the first value eta ₁ is started. Moreover, since the boom undulation direction is not considered, for example, the load factor η is 100%
When driving the boom in the upright direction from the stopped state,
Although the drive in the rising direction is safe and its speed does not need to be limited, the rising speed is increased little by little until the load factor η falls to the first value η ₁ .

When such control is executed, not only does the operator feel uncomfortable, but also the work efficiency is significantly reduced because the undulating speed is unnecessarily limited.

In view of the above circumstances, the present invention provides a crane boom hoist control method and apparatus which can guarantee a safe stop of a boom hoist drive without giving a sense of incongruity to an operator and without lowering work efficiency. The purpose is to provide.

[0008]

As a means for solving the above problems, the present invention detects a load factor of a crane,
In the crane boom hoisting control method for stopping the boom hoisting drive when the detected load factor matches a preset stop load factor, the boom hoisting direction is determined, and when the direction is the tilting direction, The lower the deceleration start load ratio is calculated as the value corresponding to the lodging speed is higher, and the deceleration of the boom lodging is started when the detected load ratio matches the deceleration start load ratio (claim 1).

In this method, if the target lodging speed calculated for the purpose of this deceleration exceeds the commanded inputting speed inputted from the outside during the boom falling-down deceleration, the input commanded lodging speed is set to the target lodging speed. Thereby, a more excellent effect as described below can be obtained (claim 2).

Further, the present invention includes a load factor detecting means for detecting a load factor of the crane, and stops the boom raising / lowering drive when the detected load factor matches a preset stop load factor. In the control device, when the boom is driven in the falling direction, first calculating means for calculating a lower deceleration start load ratio as the value corresponding to the lowering speed is higher, and the detected load ratio is set to the deceleration start load ratio. A second calculating means for calculating a target lodging speed for decelerating the winch from the time of the coincidence; and a deceleration control means for controlling the lodging of the boom based on the target falling speed calculated by the second calculating means. (Claim 3).

In this device, the first calculating means may be configured to calculate the deceleration start load ratio based on a commanded fall speed input from the outside (claim 4).

If the target lodging speed calculated by the second calculating means is higher than the commanded inputting speed inputted from the outside during the boom falling-down deceleration, the inputted commanded inputting speed is set as the target lodging speed and the winch drive is performed. By configuring the deceleration control means so as to control the following, more excellent effects as described later can be obtained (claim 5).

As specific means for the deceleration control, a hydraulic actuator for driving the boom up and down, a hydraulic source for supplying hydraulic oil to the hydraulic actuator, and a hydraulic source provided between the hydraulic source and the hydraulic actuator are provided. A control valve for changing the supply flow rate of hydraulic oil from the hydraulic source to the hydraulic actuator by operating the spool, and the deceleration control means configured to operate the spool in accordance with the target lodging speed. Is preferable (claim 6).

[0014]

In the method and apparatus according to the first and third aspects, the up-and-down direction of the boom is first determined, and when this direction is the boom down-tilt direction, the boom down-tilt starts from the time when the detected load factor reaches the deceleration start load factor. Is started, and the boom lodging speed is finally reduced to a minute speed. Then, when the actual load factor reaches the stop load factor, the falling drive is stopped. Here, the deceleration start load ratio is set to a lower value as the value corresponding to the boom's lodging speed (in Claim 4, a commanded sleeping speed input from the outside) is set higher. That is, when a long time is required for braking before stopping the boom, the deceleration is started from a relatively early point in time. Conversely, when the falling speed is low, that is, when braking until stopping can be performed in a short time, the comparison is made. The normal drive control is continued without starting the deceleration until a very late time.

In the method and the apparatus according to the second and fifth aspects, during the boom lodging deceleration, the target lodging speed calculated by the second calculating means is compared with an externally input commanded sleeping speed, and the former is determined to be the latter. If it exceeds, the commanded lodging speed is set as the target lodging speed, and the winch drive is controlled based on this.

In the apparatus according to the sixth aspect, the operation flow rate of the operating oil to the hydraulic actuator is adjusted by the operation of the spool in the control valve provided between the winch driving hydraulic actuator and the hydraulic power source. Is controlled.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, a boom 3 is mounted on a crane body 1 so that the boom 3 can be raised and lowered around a boom pin 2, and a winch drum 4A for lifting loads and a winch drum 4B for raising and lowering the boom are mounted.

The rope 6A pulled out from the winch drum 4A is hung on a sheave 7 of a boom head, and the hook block 8 is suspended by the rope 6. The rope 6B pulled out from the winch drum 4B is wound between a pair of moving pulleys 9A, 9B, and one of the moving pulleys 9A is rotatably connected to a support member 1a on the crane main body 1 side via a pin 11. And the other moving pulley 9B
Are connected to the boom head via a guy cable 6C. Therefore, the hook block 8 is moved up and down by the rotation of the winch drum 4A, and the boom 3 is raised and lowered by the drive of the winch drum 4B.

At the base of the boom 3, a boom angle detector 5 is provided. Between the moving pulley 9A and the pin 11, a rope tension detector 13 for detecting the tension of the rope 6B is provided. ing.

FIG. 2 shows a hydraulic circuit for driving the winch drum 4B. This circuit includes a hydraulic pump 10, a tank 12, and a hydraulic motor (hydraulic actuator) 14 for driving a drum. A control valve 16 is provided between the hydraulic pump 10 and the hydraulic motor 14.

The control valve 16 comprises a three-position pilot switching valve in the illustrated example. In a neutral state where the pilot pressure is not supplied to both pilot portions 16a and 16b, the oil discharged from the hydraulic pump 10 is supplied to the hydraulic motor 14. When the oil is directly released to the tank 12 without being supplied and the hydraulic pressure is supplied to the pilot portion 16a, the discharge oil is supplied to the hydraulic motor 14 through the hydraulic pipe 18A and the return oil is released to the tank 12 through the hydraulic pipe 18B. When hydraulic pressure is supplied to the pilot section 16b,
The discharge oil is supplied to the hydraulic motor 14 through the hydraulic pipe 18B, and the return oil is released to the tank 12 through the hydraulic pipe 18A. When hydraulic pressure is supplied to the hydraulic motor 14 from the hydraulic pipe 18A, the winch drum 4B is driven to rotate in a lowering direction (boom falling direction; clockwise in FIG. 1). When hydraulic pressure is supplied from the hydraulic piping 18B, the hydraulic motor 14 and the winch drum 4B are rotated so that the winch drum 4B is driven to rotate in the hoisting direction (boom rising direction; counterclockwise direction in FIG. 1). Are linked.

The pilot pressure is supplied to each of the pilot sections 16a and 16b by a pilot hydraulic pump 22.
A and 22B are performed via the electromagnetic proportional pressure reducing valves 20A and 20B. The electromagnetic proportional pressure reducing valves 20A and 20B reduce the discharge oil of the pilot hydraulic pumps 22A and 22B to a set pressure corresponding to the electric signal input to the solenoid while using the pilot oil as the pilot pressure.
a, 16b.

In FIG. 2, reference numeral 26 denotes a main relief valve.

This apparatus includes a lever angle detector 30 as shown in FIG. 1, a deceleration start load ratio calculator 32,
A load factor calculator 34 and a motor drive controller 36 are provided.

The lever angle detector 30 detects the operation direction and the operation amount of the operation lever 28 provided in the cab. The load factor calculator (load factor detection means) 34
The rated total load is calculated from the boom angle detected by the boom angle detector 5 and the boom length (fixed in this embodiment), and the actual total load determined from the rated total load and the output signal of the rope tension detector 13 is obtained. The present load factor is calculated in real time based on the load.

The deceleration start load ratio calculator (first calculation means) 32 and the motor drive controller (second calculation means and deceleration control means) 36 finally determine the stop load ratio at which the detected load ratio is set in advance. The drive control of the winch drum 4B (i.e., the up / down drive control of the boom 3) is performed for the purpose of sufficiently reducing the boom lodging speed so that the vehicle can be safely stopped when it reaches (100% in this embodiment). Is what you do. The operation is shown in the flowchart of FIG.

First, the deceleration start load ratio calculator (first calculating means) 32 determines the corresponding command driving direction of the winch drum 4B (that is, the command raising / lowering direction) from the operating direction of the operating lever 28. If the direction is the hoisting direction (boom rising direction) (NO in step S1), a control signal (signal corresponding to the commanded fall speed) b corresponding to the current operation amount of the operation lever 28 is calculated (step S1).
7). Then, the motor drive controller 36 outputs the control signal b as it is to the electromagnetic proportional pressure reducing valve 20A for hoisting drive (step S10). As a result, the pilot pressure is supplied to the pilot pressure 16a of the control valve 16, the spool is operated, the winch drum 4B is driven up at a speed corresponding to the lever operation amount, and the boom 3 is driven in the upright direction. .

On the other hand, when the command driving direction is the lowering direction (boom falling direction) (YE in step S1).
S), the deceleration start load ratio calculator 32 calculates a command lowering speed (a value corresponding to the boom falling speed) corresponding to the lever operation amount.
Is calculated (step S2), and based on the command lowering speed, a deceleration required load ratio required to reduce the boom laydown speed to a predetermined minute speed at a preset deceleration is calculated (step S3). The relationship between the required deceleration load factor and the command lowering speed is determined as a proportional relationship as shown in the graph of FIG. 4. For example, when the command lowering speed is the maximum speed, it is set to 10%. You. Further, the deceleration start load factor calculator 32 calculates a value obtained by subtracting the deceleration required load factor from the stop load factor (100%) as a deceleration start load factor (step S4).

In the present invention, the relationship between the "value corresponding to the boom hoisting speed" and the deceleration start load ratio does not need to be particularly proportional but may be a relationship in which one increases and the other increases. What is necessary is just to set suitably according to the characteristic of a crane. Further, the deceleration completion load ratio may be equal to the stop load ratio, or the deceleration completion load ratio may be smaller than the stop load ratio. In the former case, the deceleration control is continued up to the stop load ratio.In the latter case, the deceleration control is continued up to the deceleration completion load ratio, and thereafter, the minute falling speed is maintained and the stop load ratio is reached. At that point, the lodging stop is executed.

After calculating the deceleration start load ratio as described above, the motor drive controller 36 determines whether or not the current load ratio is equal to or greater than the deceleration start load ratio, that is, whether or not it is within the deceleration region. (Step S5).

If the vehicle has not yet reached the deceleration area (NO in step S5), a control signal b corresponding to the lever operation amount is calculated (step S7), and the control signal b is directly used as an electromagnetic proportional for lowering drive. Output to the pressure reducing valve 20B (step S10). Thus, the winch drum 4B is driven down at a speed corresponding to the lever operation amount, and the boom 3 is driven in the falling direction.

As described above, when the boom 3 falls down and the load ratio rises and reaches the deceleration start load ratio (that is, when the vehicle enters the deceleration region; YES in step S5), the motor drive controller 36 sets the Based on the set deceleration, a control signal (a signal corresponding to the lowering speed) a corresponding to the current load factor is calculated (step S6), and the deceleration start load factor calculator 32 performs control corresponding to the lever operation amount. The signal b is calculated (step S7). Then, the motor drive controller 36
The two control signals a and b are compared with each other. Only when the control signal a is equal to or smaller than the control signal b (YES in step S8), the control signal a is input to the electromagnetic proportional pressure reducing valve 20B (step S8).
9) In other cases (NO in step S8), control signal b is input to electromagnetic proportional pressure reducing valve 20B (step S8).
10). After the falling speed is sufficiently reduced by such a deceleration control, when the load factor reaches 100%, the output of the control signal is stopped and the driving of the winch drum 4B is stopped. This stop control may be performed by the motor drive controller 36 or another device (a safety device for preventing overload). Thereby, the crane of the crane and the breakage of the machine such as the boom 3 are prevented beforehand.

According to this device, the following effects can be obtained.

A) First, the drive direction of the winch drum 4B (that is, the up-and-down direction of the boom 3) is determined, and the deceleration control is performed only when the direction is the boom inversion direction. When the boom is raised, the driving speed of the boom 3 is not limited. Therefore, the work efficiency does not decrease, and the operator does not feel uncomfortable.

B) When the boom falls, instead of fixing the load factor at which deceleration is started to a constant value, the lower the command lowering speed (command lowering speed) input from the operation lever 28, the lower the deceleration load factor. When the command lowering speed is high, deceleration is started at an early timing when the command lowering speed is high, so that reasonable boom stop control is ensured. If not, a high work efficiency can be secured by delaying the deceleration start timing.

C) Even when the vehicle enters the deceleration area, the target lodging speed (speed corresponding to the control signal a) calculated for the deceleration is equal to the commanded lodging speed (speed corresponding to the control signal b) from the operator. If it exceeds, the latter commanded fall speed is prioritized (step S8), so that a more flexible drive control that always respects the will of the operator can be executed on the safe side (ie, the low speed drive side). .

Next, a second embodiment will be described with reference to FIGS.

In the first embodiment, the motor drive controller 36 for controlling the pilot pressure is also used as the second calculating means and the deceleration control means. A pump displacement adjuster 40 is provided as a calculation means and a deceleration control means. The pump displacement adjuster 40 calculates a target pump discharge amount according to the load ratio from the time when the load ratio enters the deceleration region, and outputs a control signal corresponding to this to the electromagnetic proportional pressure reducing valve 38, The tilting angle of the variable displacement type hydraulic pump 10 is gradually changed to reduce the pump discharge amount.

As described above, in the present invention, regardless of the means for changing the boom hoisting speed, in addition to the above-described pump discharge amount control, the electromagnetic proportional pressure reducing valve 20 shown in the first embodiment can be used.
A new electromagnetic proportional pressure reducing valve may be provided between A, 20B and the control valve 16 to reduce the pilot pressure. However, if the deceleration control is performed using the control valve 16 and the electromagnetic proportional pressure-reducing valves 20A and 20B which are originally required for the drive control of the hydraulic motor 14 as in the first embodiment, the drive circuit can be further simplified. There is an advantage that the reliability can be improved.

The present invention can also take the following forms as examples.

(1) The “stop load factor” in the present invention is 100
The value is not limited to%, and may be set to a value less than 100% with a margin. Also in this case, the deceleration completion load ratio may be set to a predetermined value equal to or less than the stop load ratio.

(2) In the above embodiment, the case where the boom is driven up and down by the winch has been described. However, in the present invention, the case where the drive speed can be adjusted regardless of the specific means of the boom up / down drive. It is widely applicable.

(3) In the present invention, the “value corresponding to the falling speed” includes not only the commanded falling speed corresponding to the operation amount of the operation lever 28 but also the pilot pressure and the detected rotation amount of the boom hoisting angle detector 5. The actual boom hoisting speed calculated from the time change rate may be adopted.

[0045]

As described above, according to the present invention, the boom undulation direction is first determined, and when this direction is the boom hill direction, a value corresponding to the boom hill speed (in claim 4, an externally input signal is input). The lower the deceleration start load factor, the lower the deceleration start load factor is calculated, and the deceleration is started when the detected load factor reaches this deceleration start load factor. Only when a speed limit is required, deceleration can be performed, and there is an effect that reasonable and safe drive stop can be guaranteed without giving a sense of incongruity to the operator and without lowering work efficiency. .

Further, in the method and the device according to the second and fifth aspects, when the target lodging speed calculated by the second calculating means exceeds the commanded sleeping speed inputted from the outside during the boom lodging deceleration, The boom hoisting drive is controlled using the input commanding hoisting speed as the target hoisting speed, so that the operator's will can always be respected on the safe side (low speed driving side), and more flexible control can be executed. effective.

In the apparatus according to the sixth aspect, the supply flow rate of the hydraulic oil to the hydraulic actuator is adjusted by the operation of the spool in the control valve provided between the hydraulic actuator for boom hoisting drive and the hydraulic source. Since the boom is controlled in terms of its falling speed, a special means for adjusting the drive speed of the hydraulic actuator can be dispensed with, whereby the structure can be simplified and a more reliable device can be provided. There is.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a boom hoist control device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a winch drive circuit controlled by the boom up / down control device.

FIG. 3 is a flowchart showing a calculation control operation performed by the boom undulation control device.

FIG. 4 is a graph showing a relationship between a required deceleration load factor and a deceleration start load factor calculated in the arithmetic control operation and a command lowering speed.

FIG. 5 is an overall configuration diagram of a boom undulation control device according to a second embodiment of the present invention.

FIG. 6 is a circuit diagram of a winch drive circuit controlled by the boom up / down control device.

FIG. 7 is a graph showing a relationship between a pump discharge amount and a load factor controlled by a conventional boom hoist control device.

[Explanation of symbols]

Reference Signs List 3 boom 4B winch drum 5 boom hoisting angle detector (load factor detecting means) 6B rope 10 hydraulic pump 13 rope tension detector (load factor detecting means) 14 hydraulic motor (hydraulic actuator) 16 control valve 28 operating lever 30 lever angle detecting Device 32 deceleration start load ratio calculator (first calculation means) 34 load ratio calculator (load ratio detection means) 36 motor drive controller (second calculation means and deceleration control means) 40 pump displacement controller (second calculation means) And deceleration control means)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B66C 23/00-23/94

Claims (6)

(57) [Claims] 1. A crane boom hoist control method for detecting a load ratio of a crane and stopping the boom hoist drive when the detected load ratio matches a preset stop load ratio. When the direction is the falling direction, the lower the deceleration start load factor is calculated as the value corresponding to the falling speed is higher, and the boom tilting deceleration is started from the time when the detected load factor matches the deceleration starting load factor. Starting crane operation. 2. The crane boom hoisting control method according to claim 1, wherein the target tilting speed calculated for the purpose of the boom tilting deceleration exceeds the commanded tilting speed input from the outside when the boom tilting is decelerated. A crane boom raising / lowering control method, comprising setting a commanded lodging speed to a target lodging speed. 3. A crane boom hoist control device which includes a load factor detecting means for detecting a load factor of a crane, and stops the boom hoisting drive when the detected load factor matches a preset stop load factor. A first calculating means for calculating a lower deceleration start load ratio as the value corresponding to the lowering speed is higher when the boom is driven in the lowering direction, and a time when the detected load ratio matches the lowering speed. A second calculating means for calculating a target lodging speed for decelerating the winch, and a deceleration control means for controlling the boom lodging based on the target lodging speed calculated by the second calculating means. Characteristic crane boom hoisting control device. 4. The crane boom hoist control apparatus according to claim 3, wherein the first calculating means is configured to calculate the deceleration start load ratio based on a commanded fall speed input from outside. Crane boom undulation control device. 5. The crane boom raising / lowering control device according to claim 3, wherein the second boom is lowered during the boom lowering / lowering deceleration.
The deceleration control means is configured to control the winch drive when the target lodging speed calculated by the arithmetic means is higher than the commanded sleeping speed input from the outside, using the input commanded sleeping speed as the target sleeping speed. A crane boom undulation control device. 6. A crane boom hoist control apparatus according to claim 3, wherein the hydraulic actuator drives the boom up and down, a hydraulic source supplying hydraulic oil to the hydraulic actuator, and a hydraulic source. And a control valve provided between the hydraulic actuator and the hydraulic actuator, the control valve changing the supply flow rate of hydraulic oil from the hydraulic source to the hydraulic actuator by operating the spool, and operating the spool in accordance with the target falling speed A crane boom raising / lowering control apparatus comprising the above-described deceleration control means.