JPH0627719Y2 - Boom drive for concrete pump car - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a boom drive device for hoisting or turning a boom of a concrete pump vehicle with a boom.

[Prior Art] Among concrete pump cars, a concrete pump car with a boom is a concrete pumping mechanism that sucks and discharges concrete in a hopper with a concrete pump on a frame and a concrete pipe supporting a concrete pipe to a remote place or a high place. In order to guide the tip of the concrete pipe to a certain position, a swing platform that swingably supports the boom is installed, and the lower boom of the multi-stage boom is supported up and down on the swivel platform, and The concrete pumped by the concrete pump is conveyed through the concrete pipe supported by the boom, and discharged from the tip of the concrete pipe that is guided to the tip of the uppermost boom so that concrete can be placed. is there.

Conventionally, the boom is driven in such a concrete pump vehicle with a boom by a hydraulic circuit as shown in FIG. That is, the lower cylinder a, the middle cylinder b, and the upper cylinder c, which are provided for hoisting the lower boom, the middle boom, and the upper boom, respectively, are connected to the discharge side of the pump q via the electromagnetic switching valves d, e, and f, respectively. The cylinders a, b, c can be expanded and contracted by connecting and switching the solenoid switching valves d, e, f, and further, the forward / reverse hydraulic motor h for rotating the boom and the pump q are electromagnetically coupled. Connection is made via a switching valve i, and by switching the electromagnetic switching valve i, the swing hydraulic motor h is rotated in the forward or reverse direction to swing the boom rightward or leftward.

[Problems to be Solved by the Invention] However, in the above-described conventional boom drive device, switching between extension and contraction operations of the cylinders a, b, and c of each stage, and normal rotation and reverse rotation of the turning hydraulic motor h are performed. Solenoid switching valve d, e, f, i
Therefore, for example, when the electromagnetic switching valve d or e or f is switched in order to expand or contract the cylinder a or b or c in order to arbitrarily oscillate the boom of each stage,
In the case of the electromagnetic switching valve, as shown in FIG. 6 at the same time as the switching, the amount of oil reaches the maximum value and a large amount of oil immediately starts to flow and acts on the cylinder a, b or c, so that the boom performs a hoisting motion at once. Immediately after the switch is turned off, the pressure oil supply is stopped and the boom is suddenly stopped. As a result, the boom suddenly starts moving at each stage and is suddenly stopped, causing a large impact. The same applies to the case of turning, and the turning of the electromagnetic switching valve h for turning causes sudden start or stop of turning, resulting in large swing of the boom. For this reason, conventionally, in both the case of raising and lowering the boom and the case of turning, the operator makes the boom move little by little while turning the switch ON and OFF little by little to prevent the shock from being generated as much as possible. .

Therefore, according to the present invention, even if the transmitter switch is turned on and off, the boom does not start or stop at a predetermined flow rate immediately, and the boom starts undulating at a low speed, and the boom turns gradually. Is to be done in.

[Means for Solving the Problem] In order to achieve the above object, the present invention provides a hydraulic circuit for hoisting a multi-stage boom with a proportional solenoid valve for each hoisting cylinder of each boom. A line for connecting the potentiometer and the proportional solenoid valve via an amplifier so that the proportional solenoid valves are switched by the output of the potentiometer of the joystick lever, and further for supplying pressure oil to the hydraulic motor for swinging the boom. A proportional solenoid valve is provided in the.

[Operation] Since the opening of the proportional solenoid valve can be changed by the voltage, even if the switch is turned on, the amount of oil in the circuit is not changed by the proportional solenoid valve and the maximum flow rate is not reached immediately. Therefore, the boom gradually undulates. Be operated. Further, the turning operation is also performed stepwise.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows, as an embodiment of the present invention, the hoisting cylinders 1, 2, 3, 4 provided for each boom of each stage of a two-stage boom concrete pump truck are expanded and contracted, and The boom operation circuit made to rotate the multistage boom is shown.

A hoisting cylinder 1 for the first boom that is equipped to hoist each boom from the first boom, which is the lower boom, to the fourth boom, which is the upper boom,
The second stage boom hoisting cylinder 2, the third stage boom hoisting cylinder 3 and the fourth stage hoisting cylinder 4 are connected to a hydraulic pump 5 for supplying pressure oil, and the boom hoisting cylinders are provided in the middle. Proportional solenoid valves 6 and 7 and 8 and 9 arranged for every 1, 2, 3, and 4
Connected with the pressure oil line 10 incorporating and each proportional solenoid valve
By switching 6,7,8,9, the pressure oil line 10 can be connected to the rod side or the head side of each cylinder 1,2,3,4, and the cylinder 1,2,3,4 An oil drain line 11 for returning the oil on the head side or the rod side to the tank 12 when pressure oil is being supplied to the rod side or the head side is provided, and the proportional solenoid valves 6, 7, 8, 9 are in the neutral position. The line 13 that connects the discharge side of the hydraulic pump 5 directly to the oil drain line 11 through each proportional solenoid valve 6,7,8,9 when When it is, the pressure oil from the hydraulic pump 5 is returned from the line 13 to the tank 12 through the oil drain line 11. Further, the above proportional solenoid valves 6, 7, 8,
9, the potentiometer 16 of the joystick lever 15 on the transmitter 14 is connected via the amplifier 17 as a receiver on the concrete pump car side, and proportional to the output of the potentiometer 16 when operating the joystick lever 15. Solenoid valves 6, 7, 8, 9 are slowly switched to supply pressure oil to the head side or rod side of cylinders 1, 2, 3, 4
Allow the cylinder to be extended or shortened.

In addition, the hydraulic motor 18
The boom swing circuit 19 by
20 is installed in the same manner as each of the proportional solenoid valves for raising and lowering the boom, and the proportional solenoid valve 20 is connected to the pushbutton switch 21 on the transmitter 14.
To the proportional solenoid valve 20 by operating the switch 21.

The transmitter 14 is provided with two joystick levers 15a and 15b as shown in FIG.
With a, the first and second cylinders 1 and 2 are expanded and contracted, and with the other lever 15b, the third and fourth cylinders 3 and 4 are expanded and contracted. Install push-button type switches 21 for turning the boom right and left, and turn on the "right" switch when turning the boom to the right and the "left" switch when turning the boom to the left. .

In FIG. 1, 22 is a check valve provided in the pressure oil supply line 10 on each inlet side of each proportional solenoid valve 6, 7, 8, 9 and 20.

If the joystick lever 15 on the transmitter 14 is operated as instructed in FIG. 2 in order to extend and retract the boom of the first stage from the boom of the first stage to the boom of the fourth stage, the output of the potentiometer 16 Is transmitted to the proportional solenoid valve 6 via the amplifier 17, and the proportional solenoid valve 6 is switched according to the output of the potentiometer 16 which changes depending on the angle at which the joystick lever 15 is tilted. The flow rate of the pressure oil to the undulating cylinder 1 does not reach the maximum value immediately, but is gradually changed as shown in FIG. 3, and the flow rate is gradually increased to control the operation speed. The same applies when the other proportional solenoid valves 7, 8, 9 are switched. As a result, the boom can be smoothly moved up and down, and it is possible to prevent the occurrence of vibration due to an impact.

Further, when the "right" or "left" button of the push-button type switch 21 in FIG. 2 is pressed, the turning proportional solenoid valve 20 is excited and switched. In this case as well, the flow rate of the proportional solenoid valve 20 is changed. Control is performed and the output of the amplifier 17 is set so that the swing of the boom is performed stepwise as shown in FIG.

It should be noted that, in the above embodiment, the case where the boom is of the four-stage type has been shown, but the same applies to cases other than the four-stage boom.

[Advantages of the Invention] As described above, according to the boom drive device of the present invention, the proportional solenoid valve is incorporated in the hydraulic circuit that connects the hoisting cylinder of the multistage boom and the pressure oil supply source, and the boom is rotated. The proportional solenoid valve for turning is also installed in the hydraulic circuit that connects the hydraulic motor for hydraulic pressure and the pressure oil supply source, and these are operated by operating the switch on the operation panel. By controlling the amount with a proportional solenoid valve, the boom can be moved little by little, and the boom can be swung in stages, and the impact force of suddenly starting and stopping suddenly as in the past. It is possible to obtain an excellent effect that the problem of occurrence of vibration due to is not caused.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of a boom drive device according to the present invention, FIG. 2 is a perspective view showing an example of a control panel, and FIG. 3 shows a state of change in the amount of oil in the circuit according to the present invention. Figure, 4th
FIG. 5 is a diagram showing the relationship between the time and the operation speed of the boom swing operation according to the present invention, FIG. 5 is a schematic diagram of a hydraulic circuit showing a conventional example, and FIG. 6 is a state of change in the oil amount of the circuit in the conventional example. FIG. 1,2,3,4 …… Cylinder for undulation, 5 …… Hydraulic pump, 6,7,
8, 9 ... proportional solenoid valve, 10 ... pressure oil supply line, 14 ... transmitter, 15 ... joystick lever, 16 ... potentiometer, 17 ... amplifier, 18 ... hydraulic motor, 20 ... proportional solenoid Valve, 21 …… switch.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A proportional solenoid valve is installed in a pressure oil supply line connecting a cylinder for undulation provided for each stage of a multi-stage boom and a pressure oil supply source, corresponding to each cylinder for undulation. In addition, a proportional solenoid valve is installed in the pressure oil supply line that connects the swing hydraulic motor that rotates the boom and the pressure oil supply source,
A boom drive device for a concrete pump car, comprising a transmitter equipped with a joystick lever and a switch for turning operation and the proportional solenoid valves described above connected via an amplifier.