JPH0314755B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention automatically corrects the driving pressure of the hydraulic motor by the amount of turning moment generated by the slope when turning a hydraulic crane on a slope, so that the same turning operation can be achieved even on a slope as on a flat land. The present invention relates to a swing control device for a hydraulic crane that can be operated.

In general, hydraulic cranes generally consist of a crane in which an upper rotating body is provided on a lower traveling body so as to be able to rotate, and a boom is attached to the upper rotating body, and a hydraulic closed circuit for swinging to drive the upper rotating body. The hydraulic closed circuit for swinging is composed of a variable displacement hydraulic pump whose discharge capacity is controlled by a variable discharge capacity mechanism, a hydraulic motor which rotates the upper rotating body, and a hydraulic closed circuit that operates according to the amount of operation of the operating lever. The variable displacement hydraulic pump has a variable displacement device for operating the variable displacement mechanism, and the hydraulic pump and the hydraulic motor are connected through a hydraulic closed circuit. varies depending on the type; for swash plate type hydraulic pumps, the discharge capacity is varied by the tilting angle of the swash plate, for slanted shaft type hydraulic pumps, by the tilting angle of the cylinder block, and for radial piston type hydraulic pumps, the discharge capacity is varied by the eccentricity of the cam ring. Therefore, the variable discharge capacity mechanism corresponds to these swash plates, cylinder blocks, cam rings, etc., and the variable discharge capacity device includes a servo valve operated by an operating lever,
and a servo actuator that operates a variable discharge capacity mechanism using hydraulic pressure supplied from the servo valve.

In this way, the pump control system that employs a hydraulic closed circuit for swinging is called pressure control (torque control), which controls the drive pressure according to the amount of operation of the operating lever and controls the output torque of the hydraulic motor. do. Therefore, in order to change the driving pressure, it is sufficient to change the displacement speed of the variable discharge capacity mechanism using the operating lever, and thereby the rotation speed of the hydraulic motor can be changed. In addition, when the operating lever is in the neutral position, the hydraulic motor is in a low torque state, and the upper rotating structure can also be rotated by inertia force or external force, so-called "driving operation" is possible. It has the characteristic that the positioning of the upper revolving body can be automatically performed when lifting the upper part from the ground, a so-called "ground cutting".
This characteristic is essential for the turning characteristics of a hydraulic crane.

Incidentally, hydraulic cranes are often used for work on flat land, but depending on the situation at a construction site, etc., they may be installed on sloped land for work. In this case, in the hydraulic crane that employs the hydraulic closed circuit for swing described above, when the operating lever is in the neutral position, the differential pressure between the discharge port and suction port of the hydraulic pump is controlled to be zero. Therefore, if the parking brake is not activated, a turning moment will be generated on the revolving upper structure due to the loads of the revolving upper structure, the boom, the suspended load, etc., and the revolving upper structure will slide onto the slope against the operator's will. It has the disadvantage of turning downward.

In addition, in the hydraulic closed circuit for turning, the discharge pressure of the hydraulic pump is controlled by the operating lever, but when turning to the right and turning to the left, when turning to the uphill side and when turning to the side of the slope The load torque of the hydraulic motor differs by "turning moment x 2" when turning downward. As a result, the operability of the control lever varies greatly, making it extremely difficult to operate, which not only increases operator fatigue, but also has the disadvantage that there is a high possibility that dangerous conditions such as load swinging may occur. There is.

The present invention was developed in view of the above-mentioned drawbacks of the prior art, and when operating a hydraulic crane on a slope, the drive pressure of the hydraulic motor is automatically corrected by the turning moment generated by the slope. By making it possible to perform the same turning operation as on flat ground, it is possible to maintain the upper rotating structure in neutral when the control lever is in the neutral position, thereby improving the safety of drifting operation and ground cutting on sloped ground. This is a hydraulic crane that allows the operator to operate the lever the same amount when going up and down a slope, making it easy for the operator to operate, and preventing the occurrence of load swing. The purpose of the present invention is to provide a swing control device.

In order to achieve the above object, the features of the configuration adopted by the present invention include a boom angle detector that detects the boom angle, a load detector that detects the load of the load suspended by the boom, and a crane in the longitudinal and lateral directions. an inclination angle detector that detects the inclination angle of the upper rotating structure; an operating lever detector that detects the amount of operation of the operating lever that performs the rotation operation of the upper rotating structure; and a pressure detector that detects the discharge pressure and suction pressure of the hydraulic pump, respectively. , a displacement detector that detects displacement of the variable discharge capacity mechanism, and an arithmetic unit that receives signals from each of the detectors and outputs a control signal to a variable discharge capacity device that operates the variable discharge capacity mechanism. , the calculation device corrects the driving pressure of the hydraulic motor corresponding to the torque generated by the tilting of the crane by inputting each detection signal from the boom angle detector, the load detector, and the tilt angle detector. Then, a new pump discharge pressure on a slope is determined by adding the control lever command pressure based on the detection signal from the control lever detector and the correction amount of the drive pressure. By performing calculations and further inputting circuit pressure signals from the pressure detectors and displacement signals from the displacement detector, a control signal necessary to set the new pump discharge pressure is sent to the discharge capacity variable device. The reason is that the calculation for output is performed.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

1 to 6 show a first embodiment of the invention.

In the figure, 1 is a crane, and the crane 1 includes a lower traveling body 2, an upper rotating body 3 rotatably provided on the lower traveling body 2, and a boom provided on the upper rotating body 3 so as to be movable up and down. It is roughly composed of 4. The boom 4 can be moved up and down via a hoisting rope 6 and a pendant rope 7 wound around the gantry 5, and a hoisting rope 8,
A suspended load 10 can be lifted and hung via a hook 9.

Next, referring to the hydraulic closed circuit for driving the upper revolving structure 3, 11 is a variable displacement hydraulic pump driven by a power source (not shown) such as an engine or an electric motor, and 12 is a load. a hydraulic motor that rotates the upper revolving body 3 together with a boom 4, etc.;
13A and 13B are hydraulic pump 11 and hydraulic motor 1
The piping connecting the two is shown. 14 is a charge pump, 15 is a tank, 16 is a relief valve that sets the maximum pressure of the charge pump 14, and from the charge pump 14 are check valves 17A,
Pressure oil is supplied to the pipes 13A, 13B via 17B to prevent cavitation in each pipe 13A, 13B. 18A and 18B are relief valves, and each of the relief valves 18A and 18B is connected between the pipes 13A and 13B with the hydraulic motor 12 in between,
The maximum pressure of each of the pipes 13A and 13B is set.
A flushing valve 19 is connected between the pipes 13A and 13B in parallel with the relief valves 18A and 18B. By discharging foreign matter from the closed circuit, foreign matter is removed. The hydraulic closed circuit configured as described above is essentially the same as the conventional technology.

Further, 21 is a discharge capacity variable mechanism for making the discharge capacity of the hydraulic pump 11 variable, and as mentioned above, the discharge capacity variable mechanism 21 is such that when the hydraulic pump 11 is a swash plate type hydraulic pump, the swash plate is a slant shaft type hydraulic pump. In a pump, this corresponds to a cylinder block, and in a radial piston type hydraulic pump, a cam ring corresponds to this. ).

Reference numeral 22 denotes a discharge capacity variable device for tilting the swash plate 21 as a discharge capacity variable mechanism (hereinafter, the discharge capacity variable device 22 will be referred to as "swash plate tilting device 22" for tilting the swash plate 21). ),
The swash plate tilting device 22 includes a pilot pump 23 serving as a hydraulic pressure source, an electromagnetic servo valve 24 that controls the flow rate of pressure oil based on a control signal to be described later, and a pressure oil supplied from the servo valve 24. Therefore, it is generally composed of a servo cylinder 25 that tilts and rotates the swash plate 21. Here, the electromagnetic servo valve 24 is always held at a neutral position by a spring, and the solenoid 24A
The switching position (A) is set by inputting a control signal to
or (b). Note that 26 is a diode for preventing back electromotive force of the solenoid 24A. Further, the servo cylinder 25 includes a piston 25B that is slidably provided in the cylinder 25A and tilts the swash plate 21, chambers 25C and 25D defined by the piston 25B, and tensions in the respective chambers 25C and 25D. A spring 25 is provided to hold the swash plate 21 in a neutral position.
E, 25F.

Next, 27 is the angle θ _B of the boom 4 with respect to the horizontal plane
A boom angle detector 28 is provided on the boom 4 to detect the load of the suspended load 10 due to the boom 4.
A load detector for detecting W _W , the load detector 28
For example, the rope 6 for elevation is attached to the gantry 5.
The load W _W can be detected from the tension of the Reference numeral 29 denotes a tilt angle detector that detects the tilt angle θ in the longitudinal direction and the tilt angle θ in the horizontal direction of the crane 1 with respect to the horizontal plane. It is configured as a two-axis detector capable of detection, and is installed at a suitable location within the upper revolving body 3, preferably at the center of rotation. Reference numeral 30 denotes an operating lever provided in the operator's cab for rotating the upper revolving structure 3; 31 indicates an operating lever detector for detecting the amount of operation of the operating lever 30;
For example, a potentiometer or the like that outputs a signal proportional to the operating angle of the operating lever 30 is used.

On the other hand, 32A and 32B are pressure detectors that detect pressures P _A and P _B corresponding to the discharge pressure or suction pressure of the hydraulic pump 11;
2B is provided, for example, in the vicinity of the suction/discharge port of the hydraulic pump 11, midway between the pipes 13A and 13B.

A displacement detector 33 detects the displacement of the swash plate 21, that is, the tilt angle Y (hereinafter, the displacement detector 33 is referred to as the "tilt angle detector 33"). Yonmeter etc. are used.

Furthermore, 34 is an arithmetic device, and the arithmetic device 34, as shown in FIG. , "CPU36"
), a RAM 37 that stores each data described below.
and ROM38 that stores the written program.
It consists of On the other hand, 39 is a preprocessing circuit that performs gain adjustment, zero point adjustment, etc. of the analog signal input from each of the aforementioned detectors 27, 28, 29, 31, 32A, 32B, and 33; A multiplexer 41 for input channels provided in each stage is the multiplexer 4.
In the A/D converter provided next to 0, the A/D
The digital signal from the converter 41 is stored in the RAM 37 via the I/F 35. Furthermore, 42 is a solenoid drive circuit, and this drive circuit 42 is I/F3
The solenoid 24 of the electromagnetic servo valve 24 is
Convert to a valve operation signal to be input to A.

Next, regarding the arithmetic processing operation of the arithmetic unit 34,
This will be explained with reference to FIG.

First, the crane 1 is stopped on a slope, and the boom angle detector 27, load detector 28,
Each detection signal from the tilt angle detector 29 is stored in the RAM 37 from the I/F 35 via the preprocessing circuit 39, multiplexer 40, and A/D converter 41.
Under the control of the ROM 38, the CPU 36 executes step 1.
As shown in the figure, the following equation is calculated to find the turning torque T generated by the inclination.

T = T _C + T _S + T _F + T _W = {k ₁ + (k ₂ + W _W )・B・√1−(
_B +) ² }-β……(1) Here, k ₁ = W _C・l _C +W _S・l _S +W _BF・l _BF k ₂ =W _BP +W _F , and T _C : Counterweight Swinging torque caused by T _S : Swinging torque caused by upper rotating structure 3 T _F : Swinging torque caused by hook 9 T _W : Swinging torque caused by hanging load 10 W _W : Weight of hanging load 10 W _C : Weight of counterweight W _S : Upper turning torque Weight of body 3 W _BF : Equivalent weight of boom foot W _BP : Equivalent weight of boom point B : Length of boom 4 θ _B : Angle of boom 4 α : Angle of longitudinal inclination of upper revolving structure 3 β : Angle of inclination of upper revolving structure 3 in the longitudinal direction Lateral tilt angle l _C : Length from the center of rotation to the center of gravity of the counterweight l _S : Length from the center of rotation to the center of gravity of the upper rotating structure 3 l _BF : Length from the center of rotation to the boom foot,
represents.

Next, the CPU 36 performs the following steps as shown in the next step 2.
Based on the turning torque T, a correction amount P _K of the drive pressure of the hydraulic motor 12 necessary to generate the torque T is determined. Since this driving pressure correction amount P _K is expressed as a function proportional to the torque T,
This is done by accessing the table of the function stored in the ROM 38.

On the other hand, when the operator operates the operating lever 30 to rotate the upper revolving structure, a detection signal corresponding to the operating amount output from the operating lever detector 31 is transmitted from the I/F 35 to the RAM 37 as described above.
is memorized. Further, the ROM 38 stores a function table showing the relationship between the lever stroke of the operating lever 30 and the command pressure P _L as shown in FIG. calculates the command pressure P _L corresponding to the detected value of the operating lever detector 31 stored in .

Next, as shown in step 4, the CPU 36 calculates a new pump discharge pressure P _M in step 5 by adding the driving pressure correction amount _PK and the command pressure _PL . That is, the calculation process of P _M = P _K + P _L (2) is performed. In this case, when the upper rotating body 3 rotates in the direction up the slope, P _K >0, so the pump discharge pressure P _M becomes a larger value than the command pressure P _L , and conversely, when the upper rotating body 3 rotates in the direction going down the slope. Since P _K <0 when the pump rotates, the pump discharge pressure P _M has a value smaller than the command pressure P _L .

Further, the detected pressures P _A and P _B detected by the pressure detectors 32A and 32B and the tilt angle Y detected by the tilt angle detector 33 are stored in the RAM 37. Then, as shown in step 6, the CPU 36 receives the new pump discharge pressure P _M , detected pressures P _A , P _B , and tilting angle Y calculated as described above, and performs calculations.
A swash plate tilting signal as a control signal is input from the I/F 35 to the solenoid 24A of the electromagnetic servo valve 24 via the solenoid drive circuit 42.

Here, in the hydraulic closed circuit, the hydraulic motor 1
When the load No. 2 is an inertial load, the tilting speed of the swash plate 21 and the discharge pressure of the hydraulic pump 11 are in a proportional relationship. The plate tilting speed may be controlled.

Therefore, in step 6, the CPU 36
performs specific arithmetic processing based on the flow shown in FIG. That is, in step 6a of FIG. 5, the CPU 36 reads the actual pump pressure P before and after the hydraulic pump 11 from the detected pressures P _A and P _B of the pressure detectors 32A and 32B as P=P _A - P _B. At the same time, the tilt angle Y detected by the tilt angle detector 33 is read. Then, from the new target pump discharge pressure P _M in step 6b and the pump pressure P obtained in step 6a, the deviation ΔP is calculated as ΔP=
Calculate as P _M - P.

Next, in step 6c, an increase/decrease in the tilting angle to make the deviation ΔP zero is calculated for each cycle of the program with respect to the deviation ΔP. For this reason, ROM3
8 stores a table consisting of a control function of the swash plate tilting speed V and the deviation ΔP, V=f(ΔP), as shown in FIG. Here, in the control function shown in Fig. 6, the horizontal axis shows the deviation ΔP, the vertical axis shows the swash plate tilting speed, and the tilting angle to be increased or decreased with respect to the deviation ΔP is expressed as ΔX,
If the time is Δt, it is expressed as V=ΔX/Δt, so by accessing the control function every cycle of the program, that is, every time Δt,
Assuming that ΔX≈f(ΔP), it is possible to calculate how much the tilting angle ΔX should be increased or decreased in response to the deviation ΔP. In addition, in the control function of Fig. 6, the predetermined deviation ±
Above ΔP _C, the maximum swash plate tilting speed V _nax is constant,
This prevents extreme pressure fluctuations from occurring during one program cycle.

Next, in step 6d, it is determined whether the deviation ΔP is positive or negative, and if ΔP>0, the target tilt angle
XfΔX is calculated (step 6e), and if ΔP<0, the target tilt angle X is calculated as X←X−ΔX (step 6f). Then, in the next step 6g, the current swash plate tilt angle Y detected by the tilt angle detector 33 is subtracted from the target tilt angle X as ΔY=X−Y, and one cycle of the program is performed. swash plate 2
Calculate the swash plate tilting angle ΔY at which 1 should actually be tilted.

Furthermore, in the next step 6h, it is determined whether the tilting angle ΔY at which the swash plate 21 should be tilted, calculated as described above, is positive or negative. Then, if ΔY<0, it is determined whether the range is within the dead zone where no tilting operation is actually necessary or not, as |ΔY|> dead zone (step 6i), and if ΔY>0, ΔY> A similar judgment is made as a dead zone (step 6j). In the judgment in step 6i, if the tilt angle |ΔY|> is larger than the dead zone, the pressure on the piping 13A side
The swash plate 21 is controlled to make P _A a high voltage (step 6k), and if the tilt angle |ΔY| is within the dead zone, the swash plate 21 is maintained at its current state (step 6l).
On the other hand, if the tilt angle ΔY is larger than the dead zone in the judgment at step 6j, the pressure in the pipe 13B is
The swash plate 21 is controlled to make P _B a high pressure (step 6m), and if the tilting angle ΔY is within the dead zone, it is maintained at the current state (step 6l).

Thus, the CPU 36 completes steps 6a~
The calculation process in step 6 is performed with 6m as one cycle.The control function table in the ROM 38 is accessed based on the pump discharge pressure P _M calculated in step 5, and the necessary slope is calculated to achieve the discharge pressure P _M. The CPU 36 calculates the plate tilting speed, that is, the tilting angle ΔX, and further calculates the rotation angle detected by the tilting angle detector 33 so that the pump discharge pressure P _M matches the actual pump pressure P = P _A - P _B. The pressure of the hydraulic pump 11 is controlled every predetermined time Δt by outputting a swash plate tilt signal while performing feedback control so that the swash plate 21 changes at a preset speed from the tilt angle Y.

The present embodiment is constructed as described above, but first, the operation when the crane 1 is stopped on a slope where it is about to turn to the right and the operating lever 30 is in the neutral position will be described.

At this time, even though the operating lever 30 is in the neutral position, the upper rotating body 3 generates a right turning torque based on the inclination as shown in equation (1). As a result, the calculation device 34 calculates the turning torque T in equation (1) in step 1, and calculates the turning torque T in step 2.
Find the drive pressure correction amount P _K required to generate . On the other hand, since the operating lever 30 is in the neutral position, the command pressure P _L is zero even in the pressure metering conversion in step 3. However, even in this case, since the driving pressure correction amount P _K is not zero, the addition of equation (2) is performed in step 4,
In step 5, the pump discharge pressure P _M is calculated. Furthermore, as shown in FIG. 5, the arithmetic unit 34 calculates the tilting angle ΔX, that is, the swash plate tilting speed, for each cycle of the program necessary to reach the pump discharge pressure P _M in steps 6a to 6m, and The solenoid 24A of the electromagnetic servo valve 24 that constitutes the swash plate tilting device 22 via the drive circuit 42
outputs a swash plate tilt signal that prevents the vehicle from turning to the right.

Thus, the servo valve 24 is switched to the switching position (b), and the pressure oil from the pilot pump 23 is supplied to the chamber 25D of the servo cylinder 25, and the piston 25B is moved to the left in the figure against the spring 25E. The swash plate 21 is tilted to the right in the figure at a predetermined speed to generate a predetermined discharge pressure on the piping 13B side. Thus, the computing device 34 is connected to the pressure sensor 32.
Input the detected pressures P _A and P _B from A and 32B, and
From the control function in the figure, P = P _A − P _B and pump discharge pressure
_P
By performing feedback control so that the pressure changes at a predetermined tilting speed, the pressure on the pipe 13B side is maintained so as to be apparently zero. As a result, the hydraulic motor 12 performs a pumping action due to the inertial load of the upper rotating body 3, which is an inertial body, and the pressure on the piping 13B side becomes high by the amount of rotation torque based on the inertial load, and the pressure oil from the hydraulic pump 11 is pumped. It tries to turn to the right by the amount of leakage, but as mentioned above, the pipe 13B
Since the side also has a pump discharge pressure P _M corresponding to the turning torque, the hydraulic pump 11 and the hydraulic motor 12
The differential pressure between the supply and discharge ports and between the pipes 13A and 13B becomes substantially zero. In this way, the revolving upper structure 3 is in the same state as if it were stopped on a flat ground, and it is possible to prevent the revolving upper structure 3 from turning to the right due to inclination.

Next, when the crane 1 is stopped on a slope where it is about to turn right, and the operating lever 30 is switched to the left or right operating position in order to turn the upper rotating structure 3 to the left or right. The operation of the is described below.

At this time as well, the upper revolving body 3 generates a turning torque based on the inclination as shown in equation (1), so the calculation device 34 calculates the turning torque T of equation (1) in step 1, and calculates this turning torque T in step 2. Find the drive pressure correction amount P _K required to generate turning torque. on the other hand,
By stroking the operating lever 30 to the left turning position or right turning position, the operating lever detector 3
1 outputs a signal corresponding to this manipulated variable. As a result, the arithmetic unit 34 performs pressure metering conversion in step 3 based on the characteristics shown in FIG.
Calculate command pressure P _L. Next, in step 4, a computation is performed to add the command pressure P _L and the drive pressure correction amount _PK , which is the correction pressure on a slope, and in step 5, a new pump discharge pressure P _M on a slope is determined.
Then, in step 6, the swash plate tilting speed corresponding to the pump discharge pressure P _M is calculated, and a swash plate tilting signal is output to the solenoid 24A of the electromagnetic servo valve 24.

Assuming that the operating lever 30 is first operated to rotate the upper revolving structure 3 to the right and the electromagnetic servo valve 24 is switched to the switching position (A), the pressure oil from the pilot pump 23 is transferred to the servo cylinder. 25, the piston 25B is displaced to the right in the figure against the spring 25F, and the swash plate 21
is tilted to the left in the figure at a predetermined speed to generate a predetermined discharge pressure on the piping 13A side. At the same time, the calculation device 34 inputs the detected pressures P _A and P _B from the pressure detectors 32A and 32B, and P _A - P _B is the pump discharge pressure P _M
By performing feedback control so that the tilting angle Y from the tilting angle detector 33 changes at a predetermined tilting speed, the pressure on the piping 13A side is changed to a predetermined pressure P _M. Hold.

However, first, a case will be considered in which the operating lever 30 is operated to turn to the right while the crane 1 is in a position to turn to the right in the direction of going down a slope. In this case, since the upper rotating body 3 generates a turning torque that causes it to turn to the right due to the inertial load, the correction amount P _K of the motor drive pressure is negative. Therefore, in step 4, P _K +P _L
The pump discharge pressure P _M obtained by performing the calculation satisfies P _M <P _L. Thus, the arithmetic unit 34 outputs a swash plate tilting signal that tilts the swash plate 21 to the left in the figure based on the pump discharge pressure P _M , which is smaller than the command pressure P _L of _the operating lever 30 by the correction amount P K. By only outputting the power, the upper revolving body 3 can be turned to the right in the same state as on flat ground.

On the other hand, a case will be considered in which the operating lever 30 is operated to turn to the left while the crane 1 is in a position to turn to the right in the direction of going down a slope. In this case, since the driving pressure correction amount P _K is positive, the pump discharge pressure P _M >P _L.
Therefore, the arithmetic unit 34 generates a swash plate tilting operation that tilts the swash plate 21 to the right in the figure based on the pump discharge pressure P _L which is greater than the command pressure P _L of the operating lever 30 by the drive pressure correction amount P _K. By outputting the signal, the upper revolving body 3 can be turned to the left in the same state as on flat ground.

Next, FIG. 7 shows a second embodiment of the present invention,
The feature of this embodiment is that the swash plate tilting device as a discharge capacity variable device is constructed from four electromagnetic valves instead of the electromagnetic servo valve 24 in the first embodiment.

That is, in FIG. 7, the same components as in the first embodiment described above are denoted by the same reference numerals, and the explanation thereof will be omitted. The solenoid valves 51 and 54 are normally open, and the solenoid valves 52 and 53 are normally closed.
Solenoid valves 52, 51 and 53, 54 are connected in series between the pilot pump 23 and the tank 15, respectively, and each chamber 25C, 25D of the servo cylinder 25 is connected in series between the solenoid valves 52 and 51. They are connected between valves 53 and 54, respectively.

Since the present embodiment is configured as described above, by outputting a swash plate tilting signal from the arithmetic unit 34 to the solenoids 51A and 52A, and supplying pressure oil from the pilot pump 23 to the chamber 25C of the servo cylinder 25, The piston 25B is displaced to the right against the spring 25F, displacing the swash plate 21 to the left by an amount corresponding to the pump discharge pressure P _M , generating a predetermined discharge pressure on the piping 13A side, and starting the hydraulic motor 12. Turn right. Conversely, the solenoid 53 from the arithmetic unit 34
By outputting a swash plate tilting signal to A and 54A, the swash plate 21 is displaced to the right by an amount corresponding to the pump discharge pressure P _M , a predetermined discharge pressure is generated on the piping 13B side, and the hydraulic motor 12 is activated. Turn left.

Furthermore, FIGS. 8 to 11 show the third embodiment of the present invention.
An example is shown below.

In the first and second embodiments described above, the turning torque T generated by the tilt in step 2 is
When calculating the driving pressure correction amount P _K based on
The calculation was performed assuming the mechanical efficiency of the hydraulic motor 12 to be 100%. However, the hydraulic motor 12 has a problem in that the mechanical efficiency is not 100% due to frictional resistance, the influence of viscosity due to oil temperature, etc.

That is, the above-mentioned turning torque T and drive pressure correction
P _K is as follows.

P _K =K・T/η _T (3) where K: indicates displacement, a constant determined by reduction ratio, etc., and η _T : indicates mechanical efficiency.

Therefore, in the turning control on a slope described in the first embodiment, by including the mechanical efficiency η _T in the calculation of the drive pressure correction amount P _K , the hydraulic motor drive pressure required by the hydraulic motor 12 and the operating lever 30 can be reduced. The relationship with the manipulated variable can be more closely approximated.

This embodiment has been developed by focusing on the above-mentioned problems, and will be explained based on the embodiments shown in FIGS. 8 to 11. Note that the same components as those in the first embodiment described above are given the same reference numerals, and their explanations will be omitted.

However, reference numeral 61 denotes a rotation speed detector for detecting the rotation of the hydraulic motor 12, and the rotation speed detector 61 uses, for example, electromagnetic or optical pulse transmitting means.
Reference numeral 62 denotes an oil temperature detector for detecting the temperature of hydraulic oil in the hydraulic circuit, and the oil temperature detector 62 is provided, for example, in a circuit connected to the charge pump 14. The rotation speed detector 61 is connected to a preprocessing circuit 39 via an F/V converter 63 for converting pulses into voltage.
The oil temperature detector 62 is also connected to the preprocessing circuit 39, and the detection signals from these are sent to the arithmetic unit 34 via the multiplexer 40 and A/D converter 41.
It is stored in the RAM 37 of.

This embodiment is configured as described above, but in step 1, the calculation device 34 calculates the torque T generated by the inclination in the same way as in the first embodiment.
In step 2, a motor drive pressure correction amount P _K is calculated. In this calculation, the mechanical efficiency η _T is expressed by the following formula.

η _T = 1−C _f −C _a μn/P ……(4) However, C _f , C _d : Friction coefficient, μ : Viscosity, n : Rotation speed of hydraulic motor 12 , P : Introduction to outflow of hydraulic motor 12 Further, the viscosity μ is expressed as a function of oil temperature, μ=f(t), as shown in FIG.

Therefore, since the mechanical efficiency η _T is expressed as a function of the rotation speed n of the hydraulic motor 12, the pressure P, and the oil temperature t, in step 2, the arithmetic unit 34
Store the table of μ=f(t) in ROM38, and
36 accesses the rotation speed n, pressure P, and oil temperature t stored in the RAM 37, and the table showing μ=f(t) in the ROM 38, and calculates equations (3) and (4). Find the driving pressure P _K including the efficiency η _t .

Furthermore, the arithmetic processing in steps 3 to 6 is performed, and a swash plate tilting signal is output to the solenoid 24A of the electromagnetic servo valve 24 to control the tilting of the swash plate 21. This makes it possible to perform turning control that takes into account the influence of viscosity caused by oil temperature and frictional resistance.

In each of the above embodiments, a swash plate type hydraulic pump is used as the hydraulic pump 11, and a swash plate 21 is used as the discharge capacity variable mechanism, but a slant axis type hydraulic pump or a radial type hydraulic pump may also be used. When using the control signal, the control signals outputted from the arithmetic unit 34 become a cylinder block tilting signal and a cam ring displacement signal.

The swing control device for a hydraulic crane according to the present invention, as described in detail above, can perform the same swing operation even on a slope as on a flat ground, and therefore has the following effects.

Even if the swing control lever is held in the neutral position with the parking brake inactive, the upper revolving structure can be held stationary, making it possible to carry out swinging turns on slopes, and to lift suspended loads. It is possible to ensure the safety of ground cutting during lifting, and also to prevent the upper revolving structure from running away.

Since the operating amount of the operating lever can be the same when turning down a slope and when turning up a slope, even an unskilled operator can easily perform turning operations on a slope. It is possible to improve operability and reduce operator fatigue.

Since the swing operation is easy, it is possible to prevent the danger of hanging loads from swinging out and improve the safety of work on slopes.

Since it is possible to perform control that takes into account the influence of oil temperature during turning operations on slopes, it is possible to maintain acceleration performance similar to that on flat lands.

Even in the case where the lower traveling body is a floating crane capable of navigating underwater, it is possible to perform a turning operation that takes into account the rocking caused by waves (the inclination of the upper rotating body).

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention, FIG. 1 is an overall configuration diagram thereof, FIG. 2 is a circuit configuration diagram consisting of each detector and an arithmetic device, and FIG. 3 is an arithmetic operation diagram. An explanatory diagram explaining the processing in the device, FIG. 4 is a diagram showing the relationship between the operating lever stroke and the command pressure,
FIG. 5 is a flow diagram showing a program for controlling the swash plate tilting angle, FIG. 6 is a diagram showing the relationship between deviation and swash plate tilting speed, and FIG. 7 is a second embodiment of the present invention. 8 to 11 show a third embodiment of the present invention, FIG. 8 is an overall configuration diagram thereof, and FIG. 9 is a circuit configuration consisting of each detector and an arithmetic device. FIG. 10 is an explanatory diagram for explaining the processing in the arithmetic unit, and FIG. 11 is a diagram showing the relationship between oil temperature and viscosity. 1... Crane, 2... Lower traveling body, 3... Upper revolving body, 4... Boom, 10... Hanging load, 11...
...Hydraulic pump, 12...Hydraulic motor, 13A, 1
3B... Piping, 21... Variable discharge capacity mechanism, 22
... Discharge capacity variable device, 27 ... Boom angle detector, 28 ... Load detector, 29 ... Inclination angle detector, 30 ... Control lever, 31 ... Control lever detector, 32A, 32B ... Pressure Detector, 33...
Displacement detector, 34...Arithmetic unit, 39...Preprocessing circuit, 40...Multiplexer, 41...A/D
Converter, 51, 52, 53, 54... Solenoid valve, 6
1... Rotation speed detector, 62... Oil temperature detector.

Claims (1)

[Claims] 1. A crane in which a lower traveling body is provided with an upper rotating body so as to be able to rotate, and a boom is attached to the upper rotating body, a variable displacement hydraulic pump whose discharge capacity is controlled by a variable discharge capacity mechanism, and the upper rotating body. A hydraulic crane having a hydraulic motor for rotationally driving a revolving body, the hydraulic pump and the hydraulic motor being connected through a hydraulic closed circuit, comprising: a boom angle detector for detecting the angle of the boom; and a boom angle detector for detecting the angle of the boom; a load detector that detects the load of the suspended load; a tilt angle detector that detects the tilt angle of the crane in the longitudinal direction and the left-right direction; and a tilt angle detector that detects the operation amount of the operating lever that performs the rotation operation of the upper rotating structure. A control lever detector, a pressure detector that detects discharge pressure and suction pressure of the hydraulic pump, respectively, a displacement detector that detects displacement of the variable discharge capacity mechanism, and signals from each of the detectors are inputted. , and a calculation device that outputs a control signal to a variable discharge capacity device that operates the variable discharge capacity mechanism, and the calculation device outputs each detection signal from the boom angle detector, the load detector, and the inclination angle detector. is input, a calculation is performed to determine the correction amount of the drive pressure of the hydraulic motor corresponding to the torque generated by the tilting of the crane, and then the command pressure of the operating lever is calculated based on the detection signal from the operating lever detector. Calculation is performed to obtain a new pump discharge pressure on a slope by adding the correction amount of the driving pressure and the circuit pressure signal from each pressure detector and the displacement signal from the displacement detector are input. A swing control device for a hydraulic crane, characterized in that the swing control device for a hydraulic crane is configured to perform a calculation to output a control signal necessary for setting the new pump discharge pressure to the discharge capacity variable device.