JP7443120B2 - crane - Google Patents

Description

The present invention relates to a crane.

As background technology in this technical field, for example, Patent Document 1 states, ``Rotation amount detectors are provided on the shafts of the sheaves of the main hoisting winch and the auxiliary hoisting winch, and the amount of rope movement from the reference point is calculated from each detected value. During synchronization control, a control signal corresponding to the operation amount of the synchronization lever is output to the electromagnetic proportional valve, which drives the winch up (down).At this time, if the deviation in the rope movement exceeds a minute value, , a control signal is output to the control valve with the larger amount of rope movement, and the pilot pressure is reduced.This slows down the drive of the winch, the amount of movement of each rope becomes equal, and the suspended load is lifted and lowered horizontally. .'' is stated.

Japanese Patent Application Publication No. 2000-143174

The technique described in Patent Document 1 is effective when a cutter is suspended from the tip of a rope and lowered at an extremely low speed (for example, 60 cm/min). However, when a bucket is attached to the end of a rope and the work is carried out at high speeds (e.g. 50 m/min) (e.g. continuous wall excavation work using a bucket), a control valve with a large flow rate is required, and such a control valve is required to have a high flow rate. It is difficult to precisely control and synchronize multiple winches with high precision.

Therefore, an object of the present invention is to provide a crane that can synchronize multiple winches with high precision.

In order to achieve the above object, one aspect of the crane according to the present invention includes: a hydraulic source; a first hydraulic motor that is driven by pressure oil from the hydraulic source and drives a rope to be hoisted and hoisted down ; a first inlet side conduit through which pressure oil supplied from the hydraulic source flows toward the first hydraulic motor when the first hydraulic motor is driven down; and a lowering drive of the first hydraulic motor; a first outlet side conduit through which pressure oil discharged from the first hydraulic motor flows, and a first bypass conduit connecting the first inlet side conduit and the first outlet side conduit. and between the first bypass pipe and the first hydraulic motor, and provided on the first outlet side pipe, when the first hydraulic motor is driven down, the first a first hoisting-down limiting means for limiting the rotation of the hydraulic motor in the hoisting-down direction; a first valve provided in the first bypass conduit; and a rotation speed or amount of rotation of the first hydraulic motor. a first rotation detection means that detects directly or indirectly; a second hydraulic motor that is driven by pressure oil from the hydraulic source and drives the rope to be hoisted up and down ; and the second hydraulic pressure. a second inlet side conduit through which pressure oil supplied from the hydraulic source flows toward the second hydraulic motor when the motor is driven down; a second outlet side conduit through which pressure oil discharged from the hydraulic motor flows; a second bypass conduit connecting the second inlet side conduit and the second outlet side conduit; and the second between the bypass pipe line and the second hydraulic motor, and is provided on the second outlet side pipe line, and when the second hydraulic motor is driven down, the second hydraulic motor is lowered. a second lowering limiting means for limiting rotation in the direction; a second valve provided in the second bypass pipe; and a second hydraulic motor that directly or indirectly controls the rotation speed or amount of rotation of the second hydraulic motor. a second rotation detecting means for detecting the rotation of the first hydraulic motor and the second hydraulic motor based on the detection results of the first rotation detecting means and the second rotation detecting means. The operation of at least one of the first valve and the second valve is controlled so as to synchronize the amount of rotation of each of the valves.

According to the present invention, multiple winches can be synchronized with high precision. Note that problems, configurations, and effects other than those described above will be made clear by the description of the embodiments below.

FIG. 1 is a side view of a crane according to an embodiment of the present invention. It is a hydraulic circuit diagram of the crane concerning this embodiment. 3 is a flowchart showing a procedure for winch synchronization control. It is a hydraulic circuit diagram of a crane concerning other embodiments.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a crane according to an embodiment of the present invention. The crane 1 shown in FIG. 1 is a crawler crane, and is applied, for example, to excavation work using a continuous wall construction method. The crane 1 includes a traveling body 2, a rotating body 4 rotatably mounted on the traveling body 2 via a rotating device 3, a boom 5 attached to the tip of the rotating body 4 so as to be able to raise and lower, and a boom 5. A bucket 16, which is an example of an excavation device, is suspended by a main hoisting rope 12 passing through the sheave 10 and an auxiliary hoisting rope 13 passing through the sheave 11. .

The main winding rope 12 and the auxiliary winding rope 13 are respectively wound around the main winding winch 6 and the auxiliary winding winch 7 mounted on the revolving structure 4, and each rope 12, 13 is wound up or let out by driving each winch 6, 7. bucket 16 is raised and lowered. As will be described in detail later, in order to horizontally raise and lower the bucket 16, control is performed to synchronize the drives of the winches 6 and 7 (synchronization control). A pendant rope 14 is connected to the tip of the boom 5, and when the hoisting rope 15 is wound up or let out by driving the hoisting winch 8 mounted on the revolving body 4, the boom 5 is connected to the boom 5 via the pendant rope 14. is raised and lowered.

FIG. 2 is a hydraulic circuit diagram of the crane according to this embodiment. As shown in FIG. 2, the hydraulic circuit in this embodiment includes an engine 20 as a prime mover, hydraulic pumps 21 and 22 (hydraulic sources), a hydraulic circuit HC1 for driving the main winch 6, and an auxiliary winch. 7, a main operating lever 70 (first operating device) through which the operator inputs hoisting and lowering commands for the main hoisting winch 6, and a main operating lever 70 (first operating device) through which the operator inputs hoisting and lowering commands for the auxiliary hoisting winch 7. It mainly includes an auxiliary operation lever 71 (second operation device). Note that E1 to E10 indicate electrical wiring.

The hydraulic pump 21 and the hydraulic pump 22 are, for example, variable displacement piston pumps, and are driven by the engine 20. The hydraulic circuit HC1 and the hydraulic circuit HC2 are connected in series to the hydraulic pumps 21 and 22 (series circuit), and the pressure oil discharged from the hydraulic pumps 21 and 22 is sent to the hydraulic circuit HC1 and then to the hydraulic circuit HC2. It flows and returns to tank 23.

The hydraulic circuit HC1 includes a hydraulic motor 31 (first hydraulic motor) which is a hydraulic actuator, and a direction control valve 30 (first direction control valve), a pair of pipes L2 and L3 (first inlet pipe, first outlet pipe) connecting the hydraulic motor 31 and the direction control valve 30, a counterbalance valve 33, and a pipe It includes a bypass line L4 (first bypass line) that connects line L2 and line L3, and an electromagnetic switching valve 32 (first valve). The hydraulic motor 31 is driven by pressure oil discharged from the hydraulic pumps 21 and 22. The rotation of the output shaft of the hydraulic motor 31 is transmitted to the winch drum 50, and the winch drum 50 is driven up and down. Note that the counterbalance valve 33 is for restricting rotation of the hydraulic motor 31 in the lowering direction.

Similarly, the hydraulic circuit HC2 includes a hydraulic motor 41 (second hydraulic motor), which is a hydraulic actuator, and a directional control valve 40 (second hydraulic motor) that controls the flow of pressure oil supplied from the hydraulic pumps 21 and 22 to the hydraulic motor 41. 2 directional control valve), a pair of pipes L6 and L7 (second inlet side pipe, second outlet side pipe) connecting the hydraulic motor 41 and the direction control valve 40, and a counterbalance valve 43. , a bypass pipe L8 (second bypass pipe) connecting pipe L6 and pipe L7, and an electromagnetic switching valve 42 (second valve). The hydraulic motor 41 is driven by pressure oil discharged from the hydraulic pumps 21 and 22. The rotation of the output shaft of the hydraulic motor 41 is transmitted to the winch drum 51, and the winch drum 51 is driven up and down. Note that the counterbalance valve 43 is for restricting rotation of the hydraulic motor 41 in the lowering direction.

The operating levers 70, 71 are so-called electric levers, and when an operator operates the operating levers 70, 71 in one direction or the other, a control signal corresponding to the amount of operation of the operating levers 70, 71 is transmitted via electrical wiring E1, E2. and is output to the controller 60. Of course, the operating levers 70 and 71 may be hydraulic levers. The controller 60 outputs switching signals corresponding to these control signals to the pilot ports of the directional control valves 30 and 40 via electrical wiring E3 to E6. When the operating levers 70 and 71 are in the neutral position (when not operated), the directional control valves 30 and 40 are in positions B and E, respectively. When the operating levers 70, 71 are operated in one direction and a hoisting command is input to the controller 60, the states of the directional control valves 30, 40 are switched to positions A and D, respectively. On the other hand, when the operating levers 70, 71 are operated in the other direction and a lowering command is input to the controller 60, the states of the directional control valves 30, 40 are switched to positions C and F, respectively.

When the directional control valve 30 is switched to position A, the pressure oil discharged from the hydraulic pumps 21 and 22 flows in the order of pipe L1 → pipe L3 → hydraulic motor 31 → pipe L2, and the hydraulic motor 31 is the main The winding rope 12 is rotationally driven in the winding direction. On the other hand, when the direction control valve 30 is switched to position C, the pressure oil discharged from the hydraulic pumps 21 and 22 flows in the order of pipe L1 → pipe L2 → hydraulic motor 31 → pipe L3, and rotates the main winding rope 12 in the direction of winding it down.

Therefore, when the hydraulic motor 31 is driven down, the pipe L2 is the inlet pipe of the hydraulic motor 31, and the pipe L3 is the outlet pipe of the hydraulic motor 31. On the other hand, when the hydraulic motor 31 is hoisting, the pipe L3 becomes the inlet side pipe of the hydraulic motor 31, and the pipe L2 becomes the outlet side pipe of the hydraulic motor 31.

Furthermore, when the directional control valve 40 is switched to position D, the pressure oil discharged from the hydraulic pumps 21 and 22 is transferred to the pipe L1 → hydraulic circuit HC1 → pipe L5 → direction control valve 40 → pipe L7 → hydraulic motor. 41→pipe L6→direction control valve 40→pipe L9→tank 23, and the hydraulic motor 41 rotates the auxiliary winding rope 13 in the direction to wind it up. On the other hand, when the directional control valve 40 is switched to position F, the pressure oil discharged from the hydraulic pumps 21 and 22 is transferred to the pipe L1 → hydraulic circuit HC1 → pipe L5 → direction control valve 40 → pipe L6 → hydraulic motor. 41→pipe L7→direction control valve 40→pipe L9→tank 23, and the hydraulic motor 31 rotates the auxiliary winding rope 13 in the direction of lowering it.

Therefore, when the hydraulic motor 41 is driven down, the conduit L6 is the inlet side conduit of the hydraulic motor 41, and the conduit L7 is the outlet side conduit of the hydraulic motor 41 . On the other hand, when the hydraulic motor 41 is hoisting, the pipe L7 becomes the inlet pipe of the hydraulic motor 41, and the pipe L6 becomes the outlet pipe of the hydraulic motor 41.

The electromagnetic switching valves 32, 42 are normally closed by a close command output from the controller 60 via the electrical wiring E7, E8, and when an open command is output from the controller 60, the electromagnetic switching valves 32, 42 are energized. A portion of the pressure oil supplied to the hydraulic motors 31 and 41 flows through the bypass pipes L4 and L8. As a result, the flow rate of pressure oil supplied to the hydraulic motors 31 and 41 decreases. As a result, the number of rotations (amount of rotation) of the hydraulic motors 31, 41 decreases.

The maximum flow rate of the electromagnetic switching valve 32 is, for example, 30 liters/minute. On the other hand, the maximum flow rate of the directional control valve 30 is, for example, 500 liters/minute. That is, the maximum flow rate of the electromagnetic switching valve 32 is 10% or less of the maximum flow rate of the directional control valve 30. This means that the entire amount of pressure oil flowing through the hydraulic motor 31 does not need to flow through the bypass line L4, and only the flow rate of pressure oil required to synchronize the hydraulic motor 31 and the hydraulic motor 41 is passed through the bypass line L4. This is because as long as it flows, it is enough. The same applies to the relationship between the directional control valve 40 and the electromagnetic switching valve 42.

The winch drums 50, 51 are provided with rotation amount detectors 61, 62 (first rotation detection means, second rotation detection means) for detecting the amount of drum rotation, respectively. The rotation amount detectors 61 and 62 are, for example, pulse encoders, and output a predetermined number of pulses per drum rotation. Each detection signal (pulse) from the rotation amount detectors 61, 62 is input to the controller 60 via electric wiring E9, E10. The controller 60 can detect the total amount of rotation of the winch drums 50 and 51 by counting the number of pulses.

Here, since the winch drums 50 and 51 are connected to the hydraulic motors 31 and 41, respectively, detecting the amount of rotation of the winch drums 50 and 51 is the same as detecting the amount of rotation of the hydraulic motors 31 and 41. be. Therefore, in this embodiment, the amount of rotation of the hydraulic motors 31, 41 is measured by the amount of rotation of the winch drums 50, 51. Of course, the amount of rotation of the hydraulic motors 31, 41 may be directly detected.

The controller 60 includes a CPU 60a that performs various calculations, a storage device 60b such as a ROM or HDD that stores programs for executing calculations by the CPU 60a, a RAM 60c that serves as a work area when the CPU 60a executes programs, and other devices. It consists of hardware including a communication interface (communication I/F) 60d, which is an interface for transmitting and receiving data, and software stored in the storage device 60b and executed by the CPU 60a. Each function of the controller 60 is realized by the CPU 60a loading various programs stored in the storage device 60b into the RAM 60c and executing them.

Next, details of the synchronization control of the winches 6 and 7 by the controller 60 will be explained using FIG. 3. FIG. 3 is a flowchart showing a procedure for synchronization control of the winches 6 and 7 executed by the controller 60. The controller 60 monitors whether the operations of the operating levers 70 and 71 satisfy "predetermined conditions." Specifically, when the operating levers 70 and 71 are operated by the maximum amount (full lever operation) in the same direction (upward direction or downward direction), the controller 60 determines that the "predetermined condition" is satisfied (S1/ Yes), synchronization control of winches 6 and 7 is started. On the other hand, if the predetermined condition is not satisfied (S1/No), the process returns to step S1.

Next, the controller 60 calculates in real time the difference ΔN between the number of pulses N1 (total rotation amount) detected by the rotation amount detector 61 and the number of pulses N2 (total rotation amount) detected by the rotation amount detector 62. (S2), when the difference ΔN exceeds the first threshold T1 (for example, T1 = 2) (S3/Yes), an open command is output to the electromagnetic switching valve of the hydraulic circuit that drives the hydraulic motor with the larger number of pulses. (S4).

For example, when the amount of rotation of the hydraulic motor 31 is larger than the amount of rotation of the hydraulic motor 41, the electromagnetic switching valve 32 corresponding to the hydraulic motor 31 is opened. Then, a part of the pressure oil flows through the bypass pipe L4, and the flow rate of the pressure oil supplied to the hydraulic motor 31 decreases, so the rotation speed of the hydraulic motor 31 decreases, and the hydraulic motor 31 and the hydraulic pressure decrease. The motor 41 is driven in synchronization with the motor 41. When the amount of rotation of the hydraulic motor 41 is large, the number of rotations of the hydraulic motor 41 is reduced by similarly opening the electromagnetic switching valve 42, and the hydraulic motor 31 and the hydraulic motor 41 are driven in synchronization.

Next, the controller 60 determines whether the difference ΔN in the number of pulses has become equal to or less than the second threshold value T2 (for example, T2=0) (S5), and determines whether the difference ΔN has become equal to or less than the second threshold value T2. If so (S5/Yes), a close command is output to the electromagnetic switching valve opened in step S4, and the electromagnetic switching valve is closed (S6). For example, when the electromagnetic switching valve 32 is opened in step S4, the rotation speed of the hydraulic motor 31 is reduced, and the hydraulic motor 31 and the hydraulic motor 41 are synchronized (the main winch 6 and the auxiliary winch 7 are synchronized), the pulse The difference ΔN becomes 0. Then, since the answer is Yes in step S5, the controller 60 proceeds to step S6 and closes the electromagnetic switching valve 32. Then, the controller 60 returns to step S1. Note that if the result in step S3 is No, and if the result in step S5 is No, the process returns to step S2.

As explained above, according to this embodiment, the following effects can be achieved.

(1) An electromagnetic switching valve 32 is provided in the bypass pipe L4, and an electromagnetic switching valve 42 is provided in the bypass pipe L8, and at least one of the electromagnetic switching valves 32, 42 is determined based on the difference ΔN between the number of pulses of the winch drums 50, 51. By controlling to open the main winch 6 and the auxiliary winch 7, it is possible to synchronize the main winch 6 and the auxiliary winch 7 with high precision. Moreover, since it is sufficient to provide only the bypass pipes L4 and L8 and the electromagnetic switching valves 32 and 42, the hydraulic circuit configuration can be simplified.

(2) The electromagnetic switching valves 32 and 42 have a smaller maximum flow rate than the directional control valves 30 and 40, for example, about 10% of the directional control valves 30 and 40, so they are very small compared to the directional control valves 30 and 40. It requires only small parts, is inexpensive, and requires little space for installation. In addition, since the maximum flow rate is small, it is easy to adjust the flow rate of the pressure oil flowing through the bypass pipes L4 and L8 even when the electromagnetic switching valves 32 and 42 are opened and closed, and synchronized control between the main winch 6 and the auxiliary winch 7 is possible. becomes stable.

(3) Since the hydraulic circuit configuration is such that the hydraulic circuit HC1 and the hydraulic circuit HC2 are connected in series to the hydraulic pumps 21 and 22, there is no need to provide a hydraulic pump in each hydraulic circuit, and the hydraulic pump can be downsized. Moreover, even if the electromagnetic switching valve 32 of the upstream hydraulic circuit HC1 is opened, the entire amount of pressure oil discharged from the hydraulic pumps 21 and 22 flows into the downstream hydraulic circuit HC2, so that the main winch 6 and The precision of synchronization control with the auxiliary winding winch 7 is not reduced.

Here, when trying to perform synchronized control of the main winch 6 and the auxiliary winch 7 by adjusting the motor tilting of the hydraulic motors 31 and 41, the pump load pressure (holding pressure) of the hydraulic pumps 21 and 22 changes. Therefore, it is necessary to adjust the pump tilting of the hydraulic pumps 21 and 22, and synchronization control is complicated and difficult. Furthermore, if the hydraulic circuit HC1 and the hydraulic circuit HC2 are connected in series, it is very difficult to adjust the pump tilting and perform synchronized control. It becomes necessary to provide a bypass line or the like to bypass and connect to the hydraulic circuit HC2 to perform synchronized control. Therefore, the hydraulic circuit becomes complicated and large. On the other hand, in the present embodiment, synchronized control can be performed simply by controlling the opening and closing operations of the electromagnetic switching valves 32 and 42, so there is an advantage that synchronized control is simple.

(4) Control that only opens and closes the electromagnetic switching valves 32 and 42 so that the difference in total rotation amount (ΔN) between the hydraulic motor 31 and the hydraulic motor 41 falls within the range of the first threshold T1 and the second threshold T2 Therefore, synchronization control between the main winding winch 6 and the auxiliary winding winch 7 is simple.

Note that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the gist of the present invention, and all technical matters included in the technical idea described in the claims are This is the object of the present invention. Although the embodiments described above are preferred examples, those skilled in the art can realize various alternatives, modifications, variations, or improvements based on the contents disclosed in this specification. These are within the scope of the appended claims. Other embodiments will be mentioned below.

(Reference to other embodiments)
FIG. 4 is a hydraulic circuit diagram of a crane according to another embodiment. As shown in FIG. 4, the bypass pipes L4 and L8 may be provided with slow return check valves (one-way throttle valves) 80 and 81, respectively. The slow return check valves 80 and 81 allow free flow in one direction, and restrict the flow rate in the opposite direction with a throttle. For example, in the hydraulic circuit HC1, the pressure difference between the conduit L2 and the conduit L3 is large during hoisting, but the pressure difference between the conduit L2 and the conduit L3 becomes small when the hoist is lowered. Therefore, by providing a slow return check valve 80 in the bypass pipe L4, pressure oil can freely flow through the bypass pipe L4 during hoisting, and by restricting the pressure oil flowing through the bypass pipe L4 during lowering, higher accuracy can be achieved. Synchronized control of the main winding winch 6 and the auxiliary winding winch 7 can be realized. The reason for providing the slow return check valve 81 in the hydraulic circuit HC2 is also the same.

Further, as shown in FIG. 4, a start button 75 is provided for starting synchronized control between the main winch 6 and the auxiliary winch 7, and when an operation signal from the start button 75 is input to the controller 60, , the controller 60 may determine that a predetermined condition is satisfied and start tuning control. That is, whether or not the start button 75 is operated can be used as an alternative example of the process in step S1 (see FIG. 3). In this way, the crane 1 can be operated according to the operator's preference, improving usability. Further, for example, when a synchronization control command is input to the controller 60 from an external source such as a management server that manages the operation of the crane 1, the controller 60 may determine that a predetermined condition is satisfied and perform synchronization control. .

Further, instead of detecting the amount of rotation of the winch drums 50 and 51, for example, the amount of rotation of the sheaves 10 and 11 may be detected, or the amount of movement of the main hoisting rope 12 and the auxiliary hoisting rope 13 may be detected. The synchronization control of the main winding winch 6 and the auxiliary winding winch 7 may be performed based on the difference in the amount of movement. Alternatively, the number of rotations may be detected instead of the amount of rotation for synchronized control. That is, "detecting the number of rotations or the amount of rotation of the hydraulic motor" in the present invention is not limited to directly detecting the number of rotations or amount of rotation of the hydraulic motors 31, 41 with a sensor; 41, and indirectly detects the rotation speed or rotation amount of the hydraulic motors 31, 41 by detecting the rotation speed or rotation amount of the winch drums 50, 51 connected to the boom 5. It also includes indirectly detecting the rotation speed or rotation amount of the hydraulic motors 31, 41 by detecting the rotation speed or rotation amount of the sheaves 10, 11, or the movement amount or rope height of the ropes 12, 13. .

In addition, information on the winding layers and winding rows of the ropes 12, 13 wound around the winch drums 50, 51 is input to the controller 60, and based on this information, the number of revolutions or the amount of rotation of the hydraulic motors 31, 41 is controlled. It is also possible to perform correction and synchronization control between the main winding winch 6 and the auxiliary winding winch 7.

In other words, the "synchronized control" in the present invention is not limited to a configuration in which the rotation amount (rotation speed) of the main winch 6 and the auxiliary winch 7 are controlled to be the same; When the amount of movement of the ropes 12 and 13 differs with respect to the number of rotations or the amount of rotation, controlling the movement amounts of the ropes 12 and 13 to be the same corresponds to "synchronized control" of the present invention.

Further, if it is desired to finely control the flow rate of the pressure oil flowing through the bypass pipes L4 and L8, an electromagnetic proportional valve may be used instead of the electromagnetic switching valve 32. Further, depending on the value of the difference ΔN in the number of pulses, both the electromagnetic switching valve 32 and the electromagnetic switching valve 42 can be opened by a command from the controller 60.

Further, in order to perform synchronized control of the main winding winch 6 and the auxiliary winding winch 7, at least one of the electromagnetic switching valve 32 and the electromagnetic switching valve 42 may be controlled to close. For example, in FIG. 2, the electromagnetic switching valves 32 and 42 are held in the open position in a de-energized state, but if a configuration in which they are held in the closed position in the de-energized state is adopted, in order to perform synchronized control. , the control is such that at least one of the electromagnetic switching valves 32 and 42 is closed.

Although a crawler crane has been illustrated as an example of a crane, the present invention is not limited to this and can be applied to other mobile cranes such as wheel cranes, truck cranes, rough terrain cranes, and all-terrain cranes, as well as tower cranes and ceiling cranes. Applicable to all cranes such as cranes, jib cranes, retraction cranes, stacker cranes, gantry cranes, and unloaders.

1 Crane 2 Traveling body 3 Swivel device 4 Swivel body 5 Boom 6 Main winch 7 Auxiliary winch 10, 11 Sheave 12 Main rope 13 Auxiliary rope 16 Bucket 20 Engine 21, 22 Hydraulic pump (hydraulic source)
23 Tank 30 Directional control valve (first directional control valve)
31 Hydraulic motor (first hydraulic motor)
32 Solenoid switching valve (first valve)
40 Directional control valve (second directional control valve)
41 Hydraulic motor (second hydraulic motor)
42 Solenoid switching valve (second valve)
50, 51 winch drum 60 controller 70 main operating lever (first operating device)
71 Auxiliary operation lever (second operation device)
75 Start button 80, 81 Slow return check valve L2, L3 Pipe line (first inlet side pipe line, first outlet side pipe line)
L4 bypass pipe line (first bypass pipe line)
L6, L7 pipe line (second inlet side pipe line, second outlet side pipe line)
L8 bypass pipe line (second bypass pipe line)

Claims (7)

a hydraulic source;
a first hydraulic motor that is driven by pressure oil from the hydraulic source and drives the rope up and down ;
a first inlet side conduit through which pressure oil supplied from the hydraulic source flows toward the first hydraulic motor when the first hydraulic motor is driven down ;
a first outlet side conduit through which pressure oil discharged from the first hydraulic motor flows when the first hydraulic motor is driven down ;
a first bypass conduit connecting the first inlet side conduit and the first outlet side conduit;
The first hydraulic motor is provided between the first bypass conduit and the first hydraulic motor and on the first outlet side conduit, and when the first hydraulic motor is driven down, the first hydraulic motor a first lowering limiting means for restricting the rotation in the lowering direction;
a first valve provided in the first bypass pipeline;
a first rotation detection means that directly or indirectly detects the number of rotations or amount of rotation of the first hydraulic motor;
a second hydraulic motor that is driven by pressure oil from the hydraulic source and drives the rope up and down ;
a second inlet side conduit through which pressure oil supplied from the hydraulic source flows toward the second hydraulic motor when the second hydraulic motor is driven down ;
a second outlet side conduit through which pressure oil discharged from the second hydraulic motor flows when the second hydraulic motor is driven down ;
a second bypass conduit connecting the second inlet side conduit and the second outlet side conduit;
Provided between the second bypass pipe line and the second hydraulic motor, on the second outlet side pipe line, when the second hydraulic motor is driven down, the second hydraulic motor a second hoisting-down limiting means for limiting the rotation in the hoisting-down direction;
a second valve provided in the second bypass pipeline;
a second rotation detection means for directly or indirectly detecting the number of rotations or amount of rotation of the second hydraulic motor;
the first hydraulic motor so as to synchronize the respective rotation amounts of the first hydraulic motor and the second hydraulic motor based on the detection results of the first rotation detecting means and the second rotation detecting means; A crane characterized in that the operation of at least one of the valve and the second valve is controlled. The crane according to claim 1,
a first direction control valve that is provided between the hydraulic power source and the first hydraulic motor and controls the flow direction of pressure oil supplied from the hydraulic power source;
a first operating device that operates the first directional control valve;
a second direction control valve that is provided between the hydraulic power source and the second hydraulic motor and controls the flow direction of pressure oil supplied from the hydraulic power source;
further comprising a second operating device that operates the second directional control valve,
Starting control for synchronizing the first hydraulic motor and the second hydraulic motor based on operation signals from the first operating device and the second operating device satisfying a predetermined condition. Features a crane. The crane according to claim 2,
The crane characterized in that the predetermined condition is that the first operating device and the second operating device are both operated in the same direction with a maximum operating amount. The crane according to claim 2 or 3,
The first valve has a smaller maximum flow rate than the first directional control valve,
The crane, wherein the second valve has a smaller maximum flow rate than the second directional control valve. The crane according to any one of claims 1 to 4,
A crane, wherein the first hydraulic motor and the second hydraulic motor are connected in series to the hydraulic power source. The crane according to any one of claims 1 to 5,
A crane characterized in that each of the first bypass pipeline and the second bypass pipeline is provided with a slow return check valve. The crane according to any one of claims 1 to 6,
When the difference between the total number of rotations or the total rotation amount of the first hydraulic motor and the second hydraulic motor from the start of the control for synchronizing them becomes equal to or more than a first threshold value, the first valve and the second hydraulic motor Among the two valves, the valve corresponding to the hydraulic motor having the larger total rotation speed or the total rotation amount is opened, and when the difference becomes equal to or less than a second threshold value that is smaller than the first threshold value, the valve is opened. A crane characterized by closing.

Images