JP2013035617A - Constituting member lifting device of mobile crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constituting member lifting device of a mobile crane capable of lifting a constituting member of the mobile crane without slanting, by synchronizing telescoping actions of a plurality of hydraulic cylinders.SOLUTION: A fixed throttle valve 38 is arranged in a hydraulic fluid flow passage 32e through which hydraulic fluid supplied to a cylinder tube 31a flows when lifting a counterweight W by contracting the hydraulic cylinder 31, and a variable throttle valve 39 is arranged in a hydraulic fluid flow passage 32g through which hydraulic fluid supplied to the cylinder tube 31a flows when lowering the counterweight W by extending the hydraulic cylinder 31.

Description

  The present invention relates to a mobile crane constituent member lifting apparatus that lifts and lowers a constituent member by a plurality of hydraulic cylinders when attaching or detaching the constituent member of the mobile crane such as a counterweight or a winch.

  The mobile crane has a swivel that is turnably provided on an upper surface of a self-propelled vehicle and a telescopic boom that can be raised and lowered provided on the turntable. This mobile crane is configured so that a counterweight as a constituent member can be detachably attached to the rear part of the swivel base in order to ensure stability when a load is lifted at the tip of the telescopic boom.

  The mobile crane moves the counterweight placed on the upper surface of the vehicle body to the rear side of the swivel to move the counterweight to and from the rear of the swivel, and the counterweight located on the rear side of the swivel The component member raising / lowering device for performing the operation | movement which descend | falls to the state mounted in the upper surface of the vehicle body is provided.

  The component lifting device has a plurality of hydraulic cylinders arranged in the width direction of the vehicle. Each hydraulic cylinder has one end connected to the counterweight and the other end connected to the rear part of the swivel. In this counterweight lifting device, it is necessary to synchronize the expansion and contraction operations of the hydraulic cylinders so that the counterweight is not tilted during lifting.

  When a plurality of hydraulic cylinders are driven by a single hydraulic pump, the expansion and contraction of each hydraulic cylinder depends on the individual difference of each hydraulic cylinder and the difference in hydraulic oil pressure loss between the hydraulic pump and each hydraulic cylinder. Is difficult to synchronize. Therefore, the hydraulic fluid flow passages are connected to both ends of the cylinder tube of each hydraulic cylinder, and the hydraulic fluid passages for supplying hydraulic fluid for extending or shortening the hydraulic cylinders are throttled in parallel to each other so that the opening is variable. There is known one in which a variable throttle valve and a check valve are provided to synchronize the expansion and contraction operations of the hydraulic cylinders (for example, cited document 1).

Japanese Patent Laid-Open No. 2003-4006

  When the component that lifts and retracts the hydraulic cylinders is applied to a component lifting device, the weight of the counterweight becomes a load when the counterweight is raised. The pressure difference between the upstream side and the downstream side of the variable throttle valve in the supply path becomes large. In this case, even if the valve opening degree of the variable throttle valve is slightly changed, the flow rate of the hydraulic oil greatly changes. For this reason, the hydraulic cylinder cannot be expanded and contracted as intended, and it is difficult to raise and lower the counterweight without tilting.

  An object of the present invention is to provide a mobile crane constituent member lifting device capable of lifting and lowering a constituent member of a mobile crane without tilting by reliably synchronizing expansion and contraction operations of a plurality of hydraulic cylinders. It is in.

  In order to achieve the above-mentioned object, the present invention moves with respect to a mobile crane having a swivel provided so as to be turnable with respect to the vehicle, and an extendable boom provided so as to be freely raised and lowered with respect to the swivel. In a moving crane constituent member lifting device that lifts and lowers a constituent member with a plurality of hydraulic cylinders when attaching and detaching the constituent member of the crane, the operation is connected to one end side of the cylinder tube of each hydraulic cylinder and lifts the constituent member Is connected to the hydraulic oil supply passage for raising the hydraulic oil into the cylinder tube and the other end side of the cylinder tube of each hydraulic cylinder. A hydraulic circuit having a lowering hydraulic oil supply path to be supplied, and a fixed throttle valve for restricting the hydraulic oil flow path to a predetermined opening area is provided in each of the upward hydraulic oil supply paths. , Each lowering hydraulic fluid supply path, the variable throttle valve is provided for throttling the hydraulic fluid flow passage in the variable opening.

  As a result, when the component member is raised, the drive speed of each hydraulic cylinder is synchronized by adjusting the flow rate of the low-pressure hydraulic oil flowing out from each cylinder tube, and when the component member is lowered, each cylinder Since the driving speed of each hydraulic cylinder is synchronized by adjusting the flow rate of the hydraulic oil at a low pressure due to the weight of the constituent member acting when flowing into the tube, in both the upward and downward movements of the constituent member The flow rate of the hydraulic oil is accurately adjusted, and the expansion and contraction operations of the hydraulic cylinders can be accurately synchronized.

  According to the present invention, the flow rate of the hydraulic oil is accurately adjusted in both the ascending and descending operations of the constituent members, and the expansion and contraction operations of the respective hydraulic cylinders can be accurately synchronized. Can be made.

It is a side view of the mobile crane which shows one Embodiment of this invention. It is the figure which looked at the turntable which shows the connection method of a turntable and a counterweight from back. It is the figure which looked at the turntable which shows the state where the counterweight was attached with respect to the turntable from back. It is a schematic block diagram of a counterweight raising / lowering apparatus.

  1 to 4 show an embodiment of the present invention.

  As shown in FIG. 1, the mobile crane 1 including the lifting member lifting device of the present invention includes a traveling vehicle 10 and a crane device 20.

  The vehicle 10 has wheels 11 and travels using an engine as a power source. Further, on both the left and right sides of the front side and the rear side of the vehicle 10, there are provided outriggers 12 for preventing the vehicle 10 from overturning during crane work and for supporting the vehicle 10 stably.

  The crane device 20 is provided at the center in the front-rear direction of the vehicle 10 so as to be able to turn in the horizontal direction via a turning bearing 21, and can be raised and lowered with respect to the turning table 22, and can be extended and retracted. And a cabin 24 that is provided on the front side of the swivel base 22 and that performs operations related to the crane device 20.

  In the mobile crane 1, a counterweight W as a constituent member is detachably attached to the rear portion 22 a of the swivel base 22 in order to ensure stability when a load is suspended from the tip of the boom 23.

  When attaching the counterweight W to the rear portion 22a of the swivel base 22, first, as shown in FIG. 1, the counterweight W is suspended and moved by the crane device 20, and is slightly forward of the center in the front-rear direction on the top surface of the vehicle 10. The counterweight W is placed on the. Next, as shown in FIG. 2, the turntable 22 is turned so that the rear portion 22 a of the turntable 22 faces the counterweight W placed on the vehicle 10. In this state, as shown by a two-dot chain line in FIG. 2, the support base 22 b extending backward from the rear portion 22 a of the swivel base 22 and the counterweight W are connected. The rear portion 22 a of the swivel base 22 and the counterweight W are connected to each other via a counterweight lifting device 30 as a component lifting device for moving the counterweight W in the vertical direction with respect to the swivel base 22. Finally, the counterweight W mounted on the upper surface of the vehicle 10 is lifted by the counterweight lifting device 30 to complete the attachment of the counterweight W to the turntable 22 as shown in FIG.

  As shown in FIG. 4, the counterweight lifting device 30 has a pair of hydraulic cylinders 31 and a hydraulic circuit 32 for supplying hydraulic oil to each hydraulic cylinder 31.

  The hydraulic cylinders 31 are arranged at intervals in the width direction of the counterweight W. Each hydraulic cylinder 31 includes a cylindrical cylinder tube 31a whose one end face is closed, and a piston rod 31b provided to be movable in the cylinder tube 31a. On the outer peripheral surface of each cylinder tube 31a on the piston rod 31b side, an ascending hydraulic oil supply port 31c for supplying hydraulic oil for shortening the hydraulic cylinder 31 and raising the counterweight W is provided. Further, on the outer peripheral surface on the bottom side of each cylinder tube 31a, a lowering hydraulic oil supply port 31d to which hydraulic oil for extending the hydraulic cylinder 31 and lowering the counterweight W is supplied is provided. In each hydraulic cylinder 31, the bottom end of the cylinder tube 31a is connected to the counterweight W, and the end of the piston rod 31b is connected to the support base 22b.

The hydraulic circuit 32 is connected to a hydraulic pump 33 that is driven by the power of the vehicle running engine, and the suction side of the hydraulic pump 33 is connected to the hydraulic oil tank 34 via the hydraulic oil flow passage 32a. The discharge side of the hydraulic pump 33 is connected to the first port 35a of the electromagnetic direction switching valve 35 via the hydraulic oil flow passage 32b. A safety valve 36 for preventing the pressure in the hydraulic circuit 32 from exceeding a predetermined pressure is connected to the hydraulic oil flow passage 32b. A hydraulic oil tank 34 is connected to the second port 35b of the direction switching valve 35 via a hydraulic oil flow passage 32c. Each cylinder tube 31a is connected to the third port 35c of the direction switching valve 35 via a hydraulic oil flow passage 32e as a rising hydraulic oil supply passage extending from the hydraulic oil flow passage 32d and the hydraulic oil flow passage 32d. The rising hydraulic oil supply ports 31c are connected in parallel to each other. Each hydraulic fluid passage 32e is provided with a check valve 37 and a fixed throttle valve 38 having a fixed opening degree in order from the direction switching valve 35 to the rising hydraulic oil supply port 31c. Each cylinder tube 31a is connected to the fourth port 35d of the direction switching valve 35 via a hydraulic oil flow passage 32g as a downward hydraulic oil supply passage extending from the hydraulic oil flow passage 32f and the hydraulic oil flow passage 32f. The lowering hydraulic oil supply ports 31d are connected in parallel to each other. A variable throttle valve 39 having a variable opening is provided in the hydraulic oil flow passage 32g.
The check valve 37 is a pilot check valve capable of circulating hydraulic oil in the reverse direction by the pilot pressure in the hydraulic oil flow passage 32g. The fixed throttle valve 38 is formed with, for example, a circular hole-shaped throttle portion having a diameter of 0.8 mm. The variable throttle valve 39 is formed with a circular throttle-shaped throttle portion that is larger than the opening area of the fixed throttle valve 38, for example, with a valve opening of 3 mm in diameter, and the opening degree of the throttle portion is adjusted by a needle-like valve body. The

Further, as shown in FIG. 4, the counterweight lifting device 30 includes a controller 40 for controlling the switching of the direction switching valve 35 and the adjustment of the opening of the variable throttle valve 39.
The controller 40 has a CPU, ROM, and RAM. When the controller 40 receives an input signal from a device connected to the input side, the CPU reads a program stored in the ROM based on the input signal, and stores a state detected by the input signal in the RAM. The output signal is transmitted to a device connected to the output side.
A direction switching valve 35 and a variable throttle valve 39 are connected to the output side of the controller 40. An operation unit 41 for operating the vehicle 10 and the crane device 20 is connected to the input side of the controller 40.

When the operation of raising the counterweight W is input to the operation unit 41 in the moving member raising / lowering device of the mobile crane configured as described above, the hydraulic oil discharged from the hydraulic pump 33 causes the check valve 37 to flow. After passing in the forward direction, it passes through the fixed throttle valve 38 and flows into each cylinder tube 31a from each rising hydraulic oil supply port 31c. Accordingly, each hydraulic cylinder 31 is driven in a shortening direction to raise the counterweight W. Further, when each hydraulic cylinder 31 is driven in a shortening direction, the hydraulic oil flows out from each cylinder tube 31a through the lowering hydraulic oil supply port 31d. The hydraulic oil flowing out from the lowering hydraulic oil supply port 31d passes through the variable throttle valve 39 and is then discharged to the hydraulic oil tank 34.
At this time, the controller 40 adjusts the valve opening degree of the variable throttle valve 39, thereby adjusting the flow rate of the hydraulic oil flowing out from each cylinder tube 31a, and synchronizes the speed of the shortening operation of each hydraulic cylinder 31. The chamber on the bottom side of each cylinder tube 31 a is in a low pressure because it communicates with the hydraulic oil tank 34. Therefore, since the change in the flow rate of the hydraulic oil due to the adjustment of the opening degree of the variable throttle valve 39 is small, the driving speed of each hydraulic cylinder 31 can be accurately adjusted.

When an operation for lowering the counterweight W is input to the operation unit 41, the hydraulic oil discharged from the hydraulic pump 33 passes through each variable throttle valve 39 and passes through each lower hydraulic oil supply port 31d. It flows into the cylinder tube 31a. Accordingly, each hydraulic cylinder 31 is driven in the extending direction to lower the counterweight W. Further, when each hydraulic cylinder 31 is driven in the extending direction, the hydraulic oil flows out from each cylinder tube 31a through the rising hydraulic oil supply port 31c. The hydraulic oil flowing out from the ascending hydraulic oil supply port 31c passes through the fixed throttle valve 38 and then flows in the reverse direction through the check valve 37 opened by the pilot pressure in the hydraulic oil flow passage 32g. To be discharged.
At this time, the controller 40 adjusts the opening degree of the variable throttle valve 39 to adjust the flow rate of the hydraulic oil flowing into each cylinder tube 31a, and synchronizes the speed of the extension operation of each hydraulic cylinder 31. The chamber on the bottom side of each cylinder tube 31a is subjected to the weight of the counterweight W, and therefore has a lower pressure than the chamber on the piston rod 31b side of each cylinder tube 31a when the counterweight W is raised. Therefore, since the change in the flow rate of the hydraulic oil due to the adjustment of the opening degree of the variable throttle valve 39 is small, the driving speed of each hydraulic cylinder 31 can be accurately adjusted.

  Thus, according to the component crane lifting apparatus of the mobile crane of this embodiment, the hydraulic oil flow passage through which the hydraulic oil supplied to the cylinder tube 31a flows when the hydraulic cylinder 31 is shortened and the counterweight W is raised. A fixed throttle valve 38 is provided at 32e, and a variable throttle valve 39 is provided in a hydraulic oil flow passage 32g through which hydraulic oil supplied to the cylinder tube 31a flows when the hydraulic cylinder 31 is extended to lower the counterweight W. . Thus, when the counterweight W is raised, the drive speeds of the hydraulic cylinders 31 are synchronized by adjusting the flow rate of the low-pressure hydraulic oil that flows out of the cylinder tube 31a and is discharged to the hydraulic oil tank 34. Further, when the counterweight W is lowered, the driving speed of each hydraulic cylinder 31 is synchronized by adjusting the flow rate of the hydraulic oil that is low in pressure due to the weight of the counterweight W when it flows into each cylinder tube 31a. Is called. Therefore, it is possible to accurately adjust the flow rate of the hydraulic oil in both the rising and lowering operations of the counterweight W, and the expansion / contraction operation of each hydraulic cylinder 31 can be accurately synchronized. It can be lifted up and down.

  Further, a check valve 37 capable of regulating the outflow of the working oil flowing in the direction of flowing out from the cylinder tube 31a to the working oil flow passage 32e through which the working oil supplied to the cylinder tube 31a flows when the counterweight W is raised. Is provided. Thereby, in a state where the counterweight W is lifted by the hydraulic cylinder 31, it is possible to prevent the counterweight W from being lowered due to the weight of the counterweight W. Therefore, it is possible to improve safety.

  Further, the opening degree of the variable throttle valve 39 is variable within the range of the opening area larger than the opening area of the fixed throttle valve 38. As a result, the adjustment range of the flow rate of the hydraulic oil can be increased, so that the expansion and contraction operations of the hydraulic cylinders 31 can be synchronized more accurately.

  The controller 40 adjusts the valve opening of each variable throttle valve 39 to synchronize the expansion and contraction operations of the hydraulic cylinders 31. As a result, the opening degree of each variable throttle valve 39 can always be adjusted during the expansion / contraction operation of each hydraulic cylinder 31, so that the expansion / contraction operation of each hydraulic cylinder 31 can be synchronized more accurately. Become.

  In the above embodiment, the counter weight W is raised and lowered. However, the present invention is not limited to this. If it is a member which comprises the mobile crane 1, you may apply to raising / lowering of the structural members of the mobile crane 1 other than the counterweight W, such as a winch, for example.

  In the above embodiment, the counter weight W is raised by shortening the plurality of hydraulic cylinders 31 and the counter weight W is lowered by extending the plurality of hydraulic cylinders 31. It is not limited to. For example, the present invention can be applied even by a mechanism different from the above-described embodiment in which the counterweight is raised by extending a plurality of hydraulic cylinders and the counterweight is lowered by shortening the plurality of hydraulic cylinders 31. .

DESCRIPTION OF SYMBOLS 1 Mobile crane 10 Vehicle 20 Crane apparatus 30 Counterweight raising / lowering apparatus 31 Hydraulic cylinder 32 Hydraulic circuit 32e Hydraulic oil flow path 32g Hydraulic oil flow path 33 Hydraulic pump 37 Check valve 38 Fixed throttle valve 39 Variable throttle valve 40 Controller W Counterweight

Claims (4)

When attaching / detaching the components of the mobile crane to / from a mobile crane having a swivel base that is turnable with respect to the vehicle and a telescopic boom that is provided so as to be raised and lowered relative to the turn base, In the mobile crane constituent member lifting device that lifts and lowers the constituent member by the hydraulic cylinder of
Connected to one end side of the cylinder tube of each hydraulic cylinder, and to the other end side of the cylinder tube of each hydraulic cylinder, and a hydraulic fluid supply passage for raising hydraulic fluid into the cylinder tube during the operation of raising the component A hydraulic circuit having a lowering hydraulic oil supply path that is connected and supplies hydraulic oil into the cylinder tube during the operation of lowering the constituent members;
Each rising hydraulic oil supply path is provided with a fixed throttle valve that throttles the hydraulic oil flow passage to a predetermined opening area.
Each of the lowering hydraulic oil supply passages is provided with a variable throttle valve that squeezes the hydraulic oil flow passage in a variable opening degree. 2. The mobile crane according to claim 1, wherein each of the ascending hydraulic oil supply passages is provided with a check valve capable of regulating the flow of the hydraulic oil flowing in the direction of flowing out from the cylinder tube. The component raising / lowering device. The opening / closing degree of the variable throttle valve is variable in a range of an opening area larger than the opening area of the fixed throttle valve. The constituent member lifting device for a mobile crane according to claim 1 or 2. The expansion / contraction operation synchronizing means for synchronizing the expansion / contraction operation of each hydraulic cylinder that raises and lowers the structural member by adjusting the opening degree of each variable throttle valve of the hydraulic circuit is provided. The component raising / lowering device of the mobile crane of description.

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