JP3452219B2 - Hydraulic crane - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to hydraulic cranes.

[0002]

2. Description of the Related Art In a hydraulic crane, a hydraulic actuator that operates by receiving pressure oil from each hydraulic control valve raises and lowers a mast and a jib and winds and lowers a wire. Details are as follows.

(1) As the hydraulically operated valve, there are a poppet type, a rotary type and the like, but a spool type is used in a hydraulic crane. By the way, in the rotary type and spool type, the spool (hereinafter, the rotary type rotor is also referred to as the spool) operates from the neutral position (the position where the port to the hydraulic actuator is fully closed and the drain port to the tank is fully open). When moving to the position (position where the port to the hydraulic actuator is fully opened and the drain port to the tank is fully closed), the stroke (hereinafter, the rotation amount of the rotary plate is also the stroke. The stroke is the movement amount of the spool. Therefore, in the present invention, for convenience of explanation, the stroke is the movement amount of the spool with reference to the neutral position). There is a wrap area where the ports to the actuator (meter-in and meter-out ports) are open. In the lap region, a region close to the neutral position requires time for the pump side pressure to increase to the load pressure of the hydraulic actuator, or cannot increase to this load pressure when the load pressure is large, or Even if the pressure is increased, the hydraulic actuator does not operate as intended even if the operator operates the operating rod due to the flow of oil and the like, which is a dead zone region. Further, this dead zone region has a characteristic that it becomes larger as the load pressure becomes larger. Therefore, in the hydraulic crane, a check valve is provided upstream of the hydraulic actuator so that the pressure oil of the hydraulic actuator does not drain from the drain port to the tank in this dead zone. When the spool movement is controlled, this check valve opens when the pump side pressure of the hydraulically operated valve becomes equal to or higher than the load pressure of the hydraulic actuator (that is, when the lap area exceeds the dead zone area), and the hydraulic actuator is connected to the hydraulic pump. I am trying to drain the pressure oil.

(2) Further, the hydraulic crane lowers the wire which can be hoisted and unwound from the end of the mast or jib, and has a hook at the end of the wire. The sling is
The hanging load is hung on the hook, and the mast or jib raising operation by the operating rod and the wire winding and lowering operation are the main operations. That is, when the operator tilts each operating rod, the spool of the hydraulic control valve moves according to the tilting angle of the operating rod, whereby a flow rate corresponding to the amount of tilting flows into each hydraulic actuator, and these actuate. These operations include a single operation and the following composite operation. That is, if only the mast or jib raising operation is performed, the height of the suspended load changes, and the distance approaches. In this case, it takes time for the operator to re-secure the suspended load to a predetermined height, and depending on the operating environment, the mast, jib, suspended load, or the like may come into contact with peripheral members or people and cause an unexpected accident. Therefore, when operating the mast or jib,
It is usual to carry out a combined operation in which the wire winding operation and the wire winding operation are simultaneously performed.

[0005]

The conventional hydraulic crane described above has the following problems. (1) Describe the first problem. For example, fine adjustment of the suspended load height is a frequent and main work in slinging. And such fine adjustment is the spool movement control in the lap area. Of course, this spool movement control is preferably performed in a lap region having a stroke larger than that of the dead zone region because of good responsiveness and little energy loss. However, conventionally, as described above, the spool movement control in the lap region is performed by the operator by adjusting the tilt angle of the operation rod. Moreover, the operator does not have to wait for a means for grasping the dead zone area. Therefore, the operator only controls the spool movement based on experience, and controls the spool movement including the dead zone (that is, the spool movement control including the small stroke such that the check valve opening pressure cannot be obtained). There is no choice but to perform a response delay problem. Of course, the fact is that problems such as energy loss due to this delay in response have also been neglected.

(2) The second problem will be described. If the mast or jib is undulated or the wire is hoisted and unwound suddenly, or if the wire is suddenly stopped, the mast or jib sways up and down, causing operator discomfort and unfavorable safety. This problem becomes more remarkable as the load is heavier, and becomes more remarkable in the combined operation. The former is due to an increase in inertial force due to sudden acceleration / deceleration and heavy suspended load. The latter is for the following reason. The height of the suspended load in the combined operation of the mast or jib undulation operation and the wire hoisting and lowering operation is usually performed by finely adjusting the wire hoisting and hoisting speed. However, this fine adjustment is nothing but the spool movement control in the lap area. For this reason, the response delay occurs, and not only the synchronous control cannot be performed well, but also the intermittent operation including the sudden operation (that is, the smooth continuous operation is not performed), the suspended load is accelerated and decelerated, and the inertial force due to this is generated. Shake the mast or jib up and down.

In view of the above-mentioned problems of the prior art, it is an object of the present invention to provide a hydraulic crane that does not cause a response delay and does not cause vertical movement of the mast or jib.

[0008]

In order to achieve the above object, the hydraulic crane according to the first aspect of the present invention uses a hydraulic actuator that operates by receiving pressure oil from a hydraulic control valve to elevate and retract a mast or a jib and wind a wire. In a hydraulic crane for hoisting, etc., (1) crane load detection means, (2) operation signal input means corresponding to each hydraulic control valve,
(3) When an operation signal is input from the operation signal input means, first, the spool of the hydraulic control valve is moved at high speed so that the stroke corresponds to the magnitude of the crane load signal input from the crane load detection means. Next, for a stroke larger than this stroke, a control means for moving the spool at a predetermined speed is provided.

A hydraulic crane according to a second aspect of the present invention is a hydraulic crane in which a hydraulic actuator that operates by receiving pressure oil from a hydraulic control valve moves a mast or a jib up and down, and winds and lowers a wire. Crane load detection means, (2) operation signal input means corresponding to each hydraulic control valve, and (3) crane load detection means input the crane load signal, and calculate the load pressure of each hydraulic actuator from this crane load signal. When an operation signal is input from the operation signal input means, first, the spool of the hydraulic control valve is moved at a high speed so that the pump side pressure of the hydraulic control valve becomes the load pressure, and then the stroke corresponding to the movement amount is exceeded. A control means for moving the spool at a predetermined speed for a large stroke is provided.

A hydraulic crane according to a third invention is the above first crane.
In the hydraulic crane of the invention or the second invention, when the controller "next moves the spool at a predetermined speed for a stroke larger than this stroke" or "the stroke larger than the stroke corresponding to the movement amount next. Then, when moving the spool at a predetermined speed ",
The control means is characterized in that the moving speed of the spool is reduced as the crane load signal increases.

A hydraulic crane according to a fourth invention is the first crane described above.
In the hydraulic crane of the invention, the second invention, or the third invention, when the control means inputs an operation signal from the plurality of operation signal input means, the control means further "predetermined speed" of each spool.
Is a predetermined speed determined in advance according to the content of the composite operation.

[0012]

According to the first aspect of the present invention, the control means, when the operation signal is inputted from the operation signal input means, firstly, the stroke corresponding to the magnitude of the crane load signal inputted from the crane load detecting means (this stroke is a dead zone). (Corresponding to the region), the spool of the hydraulic control valve is moved at a high speed, and then, for a stroke larger than this stroke, the spool is automatically moved at a predetermined speed. Therefore,
Eliminates response delay and energy loss in the dead zone.

The second aspect of the invention limits the first aspect of the invention by paying attention to boosting which is the main cause of the dead zone region. According to the second aspect of the invention, the control means first inputs the crane load signal from the crane load detection means, obtains the load pressure of each hydraulic actuator from the crane load signal, and first inputs the operation signal from the operation signal input means. , The spool of the hydraulic control valve is moved at high speed so that the pump side pressure of the hydraulic control valve becomes the load pressure, and then the stroke of the movement amount (this stroke corresponds to the stroke for opening the check valve). With a larger stroke, the spool is automatically moved at a predetermined speed. Therefore, the response delay and energy loss in the dead zone are largely eliminated.

According to the third aspect of the invention, the control means automatically reduces the moving speed of the spool in the lap region beyond the dead zone as the crane load signal becomes larger. That is, when the suspended load becomes heavy, the spool movement control corresponding to this is automatically performed. Specifically, by applying the third aspect of the invention to, for example, winding and lowering the wire, the vertical swing of the mast or jib, which is conspicuous in the prior art as the load is heavier, is automatically prevented.

According to the fourth aspect of the present invention, during the combined operation, the control means sets the moving speed of the spool in the lap area beyond the dead zone area to a predetermined speed which is predetermined according to the content of the combined operation. Therefore, for example, in a combined operation of the mast or jib undulating operation and the wire hoisting and hoisting operation, only the wire hoisting and hoisting speed to be finely adjusted can be finely adjusted, and the vertical shaking of the mast or jib can be automatically prevented.

[0016]

EXAMPLES Examples will be described with reference to FIGS.
FIG. 9 is a side view of the hydraulic crane according to the embodiment. As shown in the figure, an example machine outrigger 1 overhanging type, working machine retractable crawler 2 hydraulic traveling, an upper hydraulic swivel, mast 3 Okoshijo-telescopic and jib 4 Okoshijo-telescopic Has become. For ease of description, the jib raising operation and the wire hoisting and hoisting operation will be mainly described below.

The jib 4 can be raised and lowered by the expansion and contraction of the hydraulic cylinder 5, and a wire 7 that can be hoisted and unwound by a hydraulic winch 6 is lowered from the tip thereof.
Is equipped with a hook 8 at the tip. Suspended load 9 on hook 8
Can be hung.

Further, as shown in FIG. 1, the example machine comprises an operation signal input means 10, a control means 20, a crane load detection means 30, and a hydraulic circuit 40. Hydraulic circuit 40
Each hydraulic actuator and a hydraulic control valve corresponding to each hydraulic actuator are housed together with an associated oil container.

The operation signal input means 10 includes a jib raising operation rod 11, a wire winding and lowering operation rod 12, and other operation rods 1.
It becomes 3 etc., and when the operator tilts it,
The operation signal S is input to the mode selection circuit 21 of the control means 20 described later.

The control means 20 is, for example, a microcomputer,
Mode selection circuit 21, clock circuit 22, addition / subtraction circuit 2
3A, 23B and other control circuit 24.

The crane load detecting means 30 detects a head-side oil pressure P a and the bottom side pressure Pb of the hydraulic cylinder 5, a piezoelectric transducer for inputting these detected values P a, the Pb to the mode selection circuit 21.

The hydraulic circuit 40 comprises a main circuit and a pilot circuit.

The main circuit causes the pressure oil sucked from the tank 42 by the three fixed displacement pumps 43a, 43b and 43c driven by the engine 41 to flow to each hydraulic actuator via each hydraulic operation valve to operate them. It is a circuit to make. The hydraulic fluid from the fixed displacement pump 43a is switched by the hydraulic control valve 45 and flows to, for example, a swing motor (not shown). The pressure oil from the fixed displacement pump 43b is switched by the hydraulic control valve 53 for raising the jib and flows to the hydraulic cylinder 5, and the hydraulic oil is also connected in parallel with the hydraulic control valve 53. For jib extension and contraction,
It is switched by each hydraulic control valve 46 for outrigger extension and flows to each hydraulic actuator (not shown). Here, reference numeral 54 is the check valve described in the section of the prior art. Reference numeral 541 is a counter balance valve. The pressure oil from the fixed displacement pump 43c is switched in the hydraulic control year 63 for wire winding and lowering and flows to the hydraulic winch 6, and also, for example, each hydraulic control valve for left and right traveling connected in parallel with the hydraulic control valve 63. It is switched at 47 and flows to a left and right traveling motor (not shown). Here, reference numeral 64 is the check valve described in the section of the prior art, like the check valve 54. The hydraulic control valves 53 and 63 are pilot proportional 6-port three-position switching valves having a neutral position for shutting off the flow to each hydraulic actuator, as shown in the figure. Reference numeral 44 is a relief valve.

In the pilot circuit, the oil sucked out from the tank 42 by the fixed displacement pump 43d driven by the engine 41 is proportional to solenoid valves 52a, 52b, 62a, 6
2b is a circuit for setting pilot pressure by switching 2b and moving spools of the hydraulic control valves 53 and 63. In the pilot circuit of the same figure, another hydraulic operation valve 45,
The description of the proportional solenoid valve S2 for 46 and 47 is omitted. The proportional solenoid valves 52a, 52b, 62
The a and 62b receive the drive current i from the adder / subtractor circuits 23A and 23B and generate a pilot pressure proportional to the magnitude of the drive current i in the pilot circuit. That is, the hydraulic control valves 53, 63
The spool moves in a stroke proportional to the drive current i from the adder / subtractor circuits 23A and 23B, and causes pressure oil to flow to the hydraulic cylinder 5 and the hydraulic winch 6 to operate them.
Details are as follows.

When the drive current i from the adder / subtractor circuit 23A is input to the proportional solenoid valve 52a, pilot pressure proportional to the magnitude of the drive current i acts on the bottom side of the hydraulic control valve 53, and the hydraulic control valve 53 is operated. Move the spool of by a stroke proportional to the pilot pressure. Conversely, when the drive current i from the adder / subtractor circuit 23A is input to the proportional solenoid valve 52b, pilot pressure proportional to the magnitude of the drive current i acts on the rising side of the hydraulic control valve 53, and the hydraulic control valve 5
The spool No. 3 is moved by a stroke proportional to the pilot pressure. In addition, the addition / subtraction circuit 23A is a dual proportional solenoid valve 5
When the drive current i is not output to 2a and 52b, the pilot pressure does not rise, the hydraulic control valve 53 is in the neutral position by the biasing springs on both sides, and the port to the hydraulic cylinder 5 is fully closed.

Similarly, when the drive current i from the adder / subtractor circuit 23B is input to the proportional solenoid valve 62a, this drive current i
The pilot pressure proportional to the magnitude of the pressure acts on the lowering side of the hydraulic control valve 63, and moves the spool of the hydraulic control valve 63 by a stroke proportional to the pilot pressure. vice versa,
The drive current i from the adder / subtractor circuit 23B is proportional to the solenoid valve 62.
When input to b, the pilot pressure proportional to the magnitude of the drive current i acts on the winding side of the hydraulic control valve 63 to move the spool of the hydraulic control valve 63 by a stroke proportional to the pilot pressure. When the adder / subtractor circuit 23B does not output the drive current i to the proportional electromagnetic years 62a and 62b, the pilot pressure does not rise, the hydraulic control valve 63 is in the neutral position by the bias springs on both sides, and the port to the hydraulic winch 6 is released. Fully close.

The other hydraulic control valves 45, 46, 47
The same applies to the above, and the drive current i generated by the control circuit 24 is based on the operation signal S1 from the other operation rod 13.
However, details are guided to a proportional solenoid valve S2 (not shown) and driven by the pilot pressure. However, all of these other hydraulic control valves 45, 46, 47 are set to the hydraulic control valve 53,
It need not be similar to 63. For example, it may be a hydraulic control valve that is operated by a direct signal from the operation signal input means 10 instead of a signal from the control means 20 (that is, a direct pull hydraulic control valve).

Next, the control of the example machine by the control means 20 will be described in detail with reference to FIGS. First, the outline of the control will be described with reference to FIG.

The mode selection circuit 21 of the control means 20 turns on the proportional solenoid valves 52a, 52b, 62a, 62b for each hydraulic load control valve 53, 63 for each crane load signal to be detected by the crane load detection means 30. Raising stroke current m (details will be described later), each crane load, and each operation content (that is, each single operation, each composite operation, each acceleration (stroke extension operation) and each deceleration (stroke contraction operation)) Proportional solenoid valve 52a,
Output speed coefficients n to 52b, 62a, and 62b (details will be described later) are stored in advance as a mathematical expression or table (step (1)). Therefore, when the crane load signal detected by the crane load detection means 30 is input, the clock circuit 2
Based on the clock signal from 2, the average value and the median value are calculated in, for example, 150 ms cycle (step (2)). Therefore, the start-up stroke current m is calculated or extracted from the storage with a value corresponding to the crane load signal having the calculated value, and the output speed coefficient n is calculated for each operation content and for each crane load signal having the calculated value. The corresponding value is calculated or extracted from the storage (step (3)). Next, when an operation signal is input from the operation signal input means 10, first, the operation content is discriminated (step (4)), and the output speed coefficient n calculated or extracted based on the discrimination result is extracted. Then, the drive current i to the proportional solenoid valves 52a, 52b, 62a, 62b is started to be output from the startup stroke current m, and thereafter, a small current based on the extracted output speed coefficient n for this startup stroke current m. Is added and output. When returning the spool, the small current based on the extracted output speed coefficient n is subtracted from the driving current i, and is output as the driving current i (however, the subtraction is up to the startup stroke current m). Is). The startup stroke current m and the output speed coefficient n will be described in detail below.

First, the startup stroke current m will be described in detail. As described in the section of the prior art, it is preferable that the spool movement control is performed in a lap region having a stroke larger than that of the dead zone region because the response is good and the energy loss is small. Further, as explained in the section of the prior art, the dead zone area becomes larger as the load pressure becomes larger. The dead zone area shows various values depending on the model and size of the hydraulic control valve. That is, the startup stroke current m is the startup drive current i to each proportional solenoid valve 52a, 52b, 62a, 62b that generates the pilot pressure for obtaining the boundary stroke exceeding the dead zone of the hydraulic control valves 53, 63. (Note that if the vehicle is decelerating, it will be the falloff current i).

The startup stroke current m in the example machine is as follows. FIG. 4 shows a hydraulic control valve 53 for raising the jib of the example machine.
The relationship Am between the startup stroke current m (vertical axis) and the crane load equivalent pressure Pa [kg / cm ² ] (details will be described later) (horizontal axis) is shown. As can be seen from the figure, the larger the crane load equivalent pressure Pa, the larger the startup stroke current m. On the other hand, FIG. 6 shows the relationship Cum between the startup stroke current m (vertical axis) of the hydraulic control valve 63 and the crane load W [kg] (details will be described later) (horizontal axis) when winding the wire of the example machine. Note that the relationship Cdm in FIG. 6 is the starting stroke current m of the hydraulic control valve 63 when the wire is unwound.
It is the relationship between (vertical axis) and crane load W [kg] (horizontal axis). As can be seen from the figure, the larger the crane load W, the larger the startup stroke current m. The above-mentioned crane load equivalent pressure Pa and crane load W will be supplementarily described below.

The hydraulic pressures P a and Pb detected by the crane load detecting means 30 are first calculated by the mode selection circuit 21 as “Pb · Ab−P a · Ah = W”. Here, Ab is a pressure receiving area on the bottom side of the hydraulic cylinder 5, Ah is a pressure receiving area on the head side of the hydraulic cylinder 5, and W is a crane load. The crane load W is the crane load W. For example, even if the hanging load is the same, the crane load W has a different value depending on the rising angle of the mast or jib. Next, the crane load equivalent pressure Pa for obtaining the rising stroke current m on the rising side of the jib 4 is calculated by "W / Ab = Pa". This crane load equivalent pressure Pa is the crane load equivalent pressure Pa.
On the other hand, the crane load equivalent pressure Pa for obtaining the start-up stroke current m on the bottom side of the jib 4 is calculated by “W / Ah = Pa”. The crane load equivalent pressure Pa is also the crane load equivalent pressure Pa.

That is, the mode selection circuit 21 stores the above relationships Am, Cum, Cdm as mathematical expressions or tables in advance, and when the hydraulic pressures P a , P b are input from the crane load detection means 30, they are obtained by the above calculation. Each proportional control valve 5 based on the crane load equivalent pressure Pa, the crane load W, and the memory.
Calculate or extract the startup stroke currents m of 3, 63.

The main values of the above relations Am, Cum and Cdm are also described on the vertical axis of the graph during the jib raising operation of FIG. 3 and the graph during the wire winding and unwinding operation of FIG. In addition,
Relationship A in FIG. 3 is the relationship when the jib is raised.
The relation Ao shows a no load, the relation A1 shows a representative value at a light load, the relation A2 shows a representative value at a medium load, and the relation A1 shows a heavy load.
Relationship B shows the relationship during the jib prone operation. Further, the relationship Cu (solid line) in FIG. 5 is the relationship at the time of wire winding operation, the relationship Cuo is a no load, the relationship Cu1 is a representative value at a light load, and the relationship Cu2 is a heavy load. The relationship Cd (dotted line) is the relationship during the wire lowering operation, the relationship Cd1 is for a light load, and the relationship Cd2 is for a heavy load.

Therefore, the mode selection circuit 21 sets the rising stroke current m corresponding to the crane load to the proportional solenoid valve (52) as soon as the operation signal is input from the operation signal input means 10.
a or 52b, 62a or 62b). Specific values of the startup stroke current m in the example machine are shown in Table 1 (these specific values are values obtained by transcribing the main values from FIGS. 4 and 6).

[0036]

[Table 1]

Next, the output speed coefficient n will be described in detail. As described in the prior art, when a hydraulic crane suddenly performs a mast or jib start-up operation or a wire hoisting and lowering operation, the mast or jib sways up and down, which not only makes the operator uncomfortable Cause interruption. The vertical swing of the mast or jib becomes more remarkable as the crane load increases and during combined operation. However, in the related art, the prevention of the vertical movement of the mast or the jib depends on the operator's empirical spool movement control.

Therefore, in the example machine, no matter how the operation rod is operated for each typical event in which the mast or the jib vertically swings, the spool is controlled only at a predetermined speed for each predetermined event during spool movement control. In order to prevent the movement of the drive current i, the increasing speed or the decreasing speed of the drive current i from the control means 20 is limited. In this way, the output speed coefficient n is a mathematical element that limits the moving speed of the spool during spool movement control. Details are as follows.

Before and after the explanation, the relation between the above event and the output speed coefficient n in the example machine will be described first. The output speed coefficient n of the example machine is only for wire hoisting and lowering operations.
It is specified as a different value for each event. That is, the output speed coefficient n at the time of raising the jib 4 is a constant value (n = 7 =
Constant). On the other hand, the output speed coefficient n at the time of winding and lowering the wire is shown in Table 1 above when it is divided into the single operation, the combined operation with the jib starting operation, the acceleration, the deceleration, the light load and the heavy load. As described above, the following 8 events were set in 7 ways.

Output speed coefficient n (= 7) during independent operation, acceleration and light load Output speed coefficient n (= 5) during independent operation, acceleration and heavy load Output speed coefficient n during independent operation, deceleration and light load (= 12) Output speed coefficient n (= 8) for single operation, deceleration and heavy load Output speed coefficient n (= 5) for composite operation, acceleration and light load Output speed coefficient during composite operation, acceleration and heavy load n (= 4) Output speed coefficient n (= 2) for combined operation, deceleration, and light load Output speed coefficient n (= 1.
8) The mode selection circuit 21 stores these.

As shown in FIG. 1, the control means 20 includes a mode selection circuit 21, a clock circuit 22, and an addition / subtraction circuit 2.
3A and 23B.

Therefore, first, the output speed coefficient n in the jib starting operation will be described. It is assumed that the jib raising operation rod 11 is suddenly fully tilted from the neutral position to the rising side. In the case of the conventional technique, the maximum drive current i (710 mA [milliampere] in FIG. 3) corresponding to the total tilt angle is immediately output to the proportional control valve 53, the jib 4 suddenly rises, and the jib 4 swings up and down. Occurs. On the other hand, in the example machine, the jib raising operation rod 1
When the operation signal from 1 is input to the mode selection circuit 21, the startup stroke current m is first calculated or extracted as described above. Then, the adder / subtractor circuit 23A adds 7 points every 20 ms based on the clock signal from the clock circuit 22, converts this into a small current, and adds this added current to the startup stroke current m while The startup stroke current m is continuously output to the proportional solenoid valve 52b. Therefore, even if the jib raising operation bar 11 is suddenly fully tilted from the neutral position to the wake-up side in this way, the spool gradually increases with time, so that the jib 4 rises up sharply as in the prior art and the mast is raised. The vertical shaking of the jib 4 does not occur. That is, these 7 points are the output speed coefficient n of the jib 4.

Further description will be given with reference to FIG. Figure 3
The addition / subtraction point V (horizontal axis) and the drive current i (vertical axis) are shown. Further, the startup stroke current m is plotted on the vertical axis. In the figure, at the start of spool movement control (that is, when the startup stroke current m is output), to is 0 point and 290 mA. On the other hand, the completion time t11 of the spool movement control in the lap region (that is, the completion time t11 of the movement of the hydraulic control valve 53 to the operating position) is 950 points, which is 450 mA. Here, in the example machine, since it gradually increases by 7 points every 20 ms, even if the operation bar 11 is fully tilted at once (acceleration) or even if it is returned from full tilt to neutral (at deceleration) 950 / 350≈2.
It takes 7 seconds. The value of the small current corresponding to the 7 points varies depending on the load, as shown in FIG. For example, with no load, Ao is 3.3 mA [≈450 × 7/9
50], if the load is A3, 1.2 mA [≈ (45
0-290) × 7/950], but even during acceleration,
Even at the time of deceleration, both the above-mentioned about 2.7 during the time from to to t11.
s.

That is, the moving speed of the spool is uniquely determined by the output speed coefficient n. It should be noted that, when t11 to t12 in FIG. 3 is 450 to 710 mA, when the operation rod is continuously tilted, the spool movement control is not stopped as soon as the spool movement control in the lap region is finished, but the operating position Is a margin drive current i for completely moving the spool against the spring. The time required during this period is about 0.1.
4s “= (1000-950) / 50 × 7 = 50/35
0≈0.14 ”, which is a high speed. That is, the area AA is a margin area in the relationship A when the jib is raised, and the area AAA is the stroke end of the spool. On the other hand, the area BBB is the stroke end of the spool in the relationship B during the jib prone operation.

Next, the output speed coefficient n during the wire winding and lowering operation will be described. In the example machine, the output speed coefficient n of the jib raising operation is set to a constant value (n = 7) as described above. On the other hand, the output speed coefficient n for wire winding and winding
As described above, 8 events, 7 types (n = 7, 5, 12,
8, 4, 2, 1.8). However, even if there are seven output speed coefficients n in this way, the operation of each output speed coefficient n is exactly the same as the operation of the output speed coefficient n in the above-described jib raising operation, and the resulting spool movement is Only the speed is different. That is, in the wire hoisting and hoisting operation, even if the operation bar 12 is operated all at once, the operation takes a time (spool movement control time) listed below according to the output coefficient n for each event.

[0046] When n = 7, 950 / 350≈2.7s When n = 5, 950/250 = 3.8s When n = 12, 950 / 600≈1.6s When n = 8, 950 / 400≈2.4s When n = 5, 950/250 = 3.8s When n = 4, 950 / 200≈4.8s When n = 2, 950/100 = 9.5s When n = 1.8, 950 / 90≈10.6s

The time t21 in FIG. 5 corresponds to the time t11 in FIG. 3, the time t22 is t12, CC becomes AA, and CCC again.
Corresponds to AAA. Therefore, these explanations are omitted.

That is, the operating rods 11 and 12 limit the maximum stroke in the spool movement control of the hydraulic control valves 53 and 63, and the output speed coefficient n limits the moving speed of the spool. Then, as is clear from the above description, the moving speed of the spool becomes slower as the output speed coefficient n becomes smaller.

Other examples will be listed below. (1) In the above embodiment, the operation signal input means 10 is of the operation rod type, but the button type of inputting operation signals by ON / OFF signals is more preferable. That is, in the operation rod type of the above-described embodiment, even if the operator fully tilts at once, the hydraulic actuator operates based on the output speed coefficient n for each event, so that the operator who is accustomed to the operation rod can perform the work reliably and Even if it is safe, you cannot wipe out the feeling of unfamiliarity in operation. However, since the button type originally does not output a proportional signal unlike the operation type, such a feeling of unfamiliarity does not occur. In the button type, acceleration means when the button is pressed (ON), and deceleration means when the hydraulic actuator stops operating from the time the finger is released from the button (OFF). Is in between. Of course, there are ON / OFF types even if they are operation type.
It is not necessary to conclude that the operating system is proportional.

(2) Although the crane load detecting means 30 in the above embodiment is a mere piezoelectric converter, it is a strain magnetic type provided on the wire 7, the jib 4, the mast 3 or a connecting pin (not shown) thereof. Alternatively, a force sensor such as a strain-electric type sensor may be used.

(3) In the above embodiment, the hydraulic pressure control valves 53 and 63 are driven by the pilot hydraulic pressure obtained by temporarily outputting the drive current i to the proportional solenoid valves 52a, 52b, 62a and 62b. The hydraulic control valves 53 and 63 may be electromagnetic control valves, and the drive current i from the control means 20 may be directly output to the electromagnetic control valves 53 and 63.

(4) In the above embodiment, only the hydraulic control valve 53 corresponding to the hydraulic cylinder 5 for raising the jib and the hydraulic control valve 63 corresponding to the hydraulic winch 6 for winding and lowering the wire are provided with a rising stroke. Although the current m and the output speed coefficient n are set, they may be set for the control valves corresponding to other hydraulic actuators.

(5) In the above embodiment, the output speed coefficient n for each event is given only to the wire hoisting and hoisting operation, but each event is also given to the jib raising operation and the operation of other operation. And the output speed coefficient n may be given.

(6) In the above embodiment, the output speed coefficient n is divided into 8 events and 7 ways for the wire hoisting and hoisting operation, but there may be any number. Further, the relationship P1 in FIG.
As shown in P2 and the relationships P3 and P4 in FIG. 8, when these can be represented by functions, the mode selection circuit 21 stores these functions in advance, and directly outputs the output speed coefficient n between the crane load W and these functions. May be calculated (these functions
It corresponds to the formula in the above embodiment). 7 and 8 show the relationship between the crane load W and the output speed coefficient n when the wire is hoisted and unwound, FIG. 7 is the time of acceleration, FIG. 8 is the time of deceleration, and the relationships P1 and P3 are the relationships of single operation. And the relations 2 and 4 show the relations during the combined operation with the jib raising operation.

(7) In the above embodiment, the detection cycle time of the crane load signal by the crane load detection means 30 is set to 150 ms, and the operation cycle time in the adder / subtractor circuits 23A and 23B is set to 20 ms. However, these cycle times are appropriately changed. You can do it. Needless to say, the output speed coefficient n changes variously depending on the set value of the calculation cycle time. For example, when the calculation cycle time is 20 ms and the output speed coefficient n is “n = 4”, and the calculation cycle time is 1
The moving speed of the spool is the same as when the output speed coefficient n is “n = 2” at 0 ms. That is, the seven output speed coefficients n in the above embodiment are merely examples.

(8) The above embodiment is a combined use of the startup stroke current m and the output speed integer n. In this case, for example, in FIGS. 3 and 5, the relationship between the number of addition / subtraction points V (horizontal axis) and the drive current i (vertical axis) is a plurality of straight lines (for example, if there are two straight lines B in FIG. BBB etc. 3
If it is a book, straight lines A1, AA, AAA and straight line A2 in FIG.
AA, AAA, etc.). Therefore, the mode selection circuit 21 may store each corresponding value based on these relationships as a table, or may store it as a set of linear functions. Further, the number of addition / subtraction points V in FIGS.
As described above, the (horizontal axis) is the added value of the output speed coefficient n for each event in 20 ms in the example machine.
= 50 × n × t (the unit of t is seconds s)], and the horizontal axis V
Can also be used as the time axis t. Therefore, the mode selection circuit 21 can also store the function f (V) that stores the number of addition / subtraction points V as a variable, as the function f (t) that has the time t as a variable. These functions also correspond to the mathematical expressions in the above embodiment.

(9) Each hydraulic control valve 53, 6 of the above embodiment
Although 3 is a three-position switching valve, any type may be used as long as the spool movement is controlled. For example,
The hydraulic control valve 53 for raising and lowering the jib may be an electromagnetic on-off valve for raising, an electromagnetic on-off valve for silling, an electromagnetic on-off valve for draining to the tank, or the like, and the synchronous drive current i may be given to each.

[0058]

As can be seen from the description of the above-mentioned embodiments, the present invention is, in short, a hydraulic crane having the means as described in the claims, and as is clear from the description of the above-mentioned embodiments, It is a hydraulic crane with no response delay and no swinging of the mast or jib.

[Brief description of drawings]

FIG. 1 is an overall control block diagram of an embodiment.

FIG. 2 is an overall control flow of the embodiment.

FIG. 3 is an addition / subtraction point V [= 5 at the time of starting the jib of the embodiment.
[0xnxt] (horizontal axis) is a relationship diagram between a startup stroke current m and a drive current i (vertical axis).

FIG. 4 is a crane load equivalent pressure Pa when the jib is raised in the embodiment.
It is a relational graph of (horizontal axis) and startup stroke current m (vertical axis).

FIG. 5 is a relational diagram of an addition / subtraction point V [= 50 × n × t] (horizontal axis) and a startup stroke current m and a drive current i (vertical axis) when winding and winding the wire according to the embodiment.

FIG. 6 is a graph showing the relationship between the crane load W (horizontal axis) and the startup stroke current m (vertical axis) when the wire is hoisted and unwound in the embodiment.

FIG. 7 is a graph showing the relationship between the crane load W (horizontal axis) and the output speed coefficient n (vertical axis) in the single operation and the combined operation during wire hoisting and hoisting acceleration of the embodiment.

FIG. 8 is a graph showing a relationship between a crane load W (horizontal axis) and an output speed coefficient n (vertical axis) in a single operation and a composite operation during wire hoisting and hoisting deceleration of the example.

FIG. 9 is a diagram showing an example of a hydraulic crane.

[Explanation of symbols]

1: Outrigger 2: Crawler 3: Mast 4: Jib 5: Hydraulic cylinder 52a, 52b: Proportional solenoid valve 53: Hydraulic control valve 6: Hydraulic winch 62A, 62B: Proportional solenoid valve 63: Hydraulic control valve 7: Wire 8: Hook 9: Suspended load 10: Operation signal input means 11: Jib starting operation rod 12: Wire winding and lowering operation rod 13: Other operations 20: Control means 21: Mode selection circuit 22: Clock circuit 23A, 23B: Addition / subtraction circuit 24: Other control circuits 30: Crane load detection device 40: Hydraulic circuit i: drive current m: Startup stroke current n: output speed coefficient

Claims (4)

(57) [Claims] 1. A mast or jib undulation expansion and contraction by a hydraulic actuator that operates by receiving pressure oil from a hydraulic control valve,
In a hydraulic crane that winds and lowers wires, (1) crane load detection means, (2) operation signal input means corresponding to each hydraulic control valve, and (3) operation signal input from operation signal input means Then, first, the spool of the hydraulic control valve is moved at high speed so that the stroke corresponds to the magnitude of the crane load signal input from the crane load detection means, and then, at a stroke larger than this stroke, a predetermined speed is reached. A hydraulic crane, comprising: a control means for moving the spool by the. 2. A mast or jib undulation expansion and contraction by a hydraulic actuator that operates by receiving pressure oil from a hydraulic control valve,
In a hydraulic crane that hoists and lowers wires, (1) crane load detection means, (2) operation signal input means corresponding to each hydraulic control valve, and (3) crane load detection means that receive crane load signals. When the load pressure of each hydraulic actuator is obtained from this crane load signal and the operation signal is input from the operation signal input means, first, the spool of the hydraulic control valve is adjusted so that the pump side pressure of the hydraulic control valve becomes the load pressure. And a control means for moving the spool at a predetermined speed for a stroke larger than the stroke of the moving amount. 3. The hydraulic crane according to claim 1 or 2, wherein the controller "when the spool is moved at a predetermined speed in a stroke larger than this stroke", or "the next is the amount of movement." When the spool is moved at a predetermined speed for a stroke larger than the stroke, the hydraulic crane is a control means for slowing the moving speed of the spool as the crane load signal increases. 4. The hydraulic crane according to claim 1, 2 or 3, wherein when the control means inputs an operation signal from a plurality of operation signal input means, the "predetermined speed" of each spool is a composite operation. A hydraulic crane characterized in that a predetermined speed is set in advance according to the contents of the above.