JPS6135742Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a hydraulic circuit for a concrete pump having a characteristic switching operation mechanism for a gate valve in the concrete pump.

(Prior art) Conventionally, in hydraulically driven piston pumps, in order to speed up the operation of the gate valve that switches between the suction and discharge strokes of concrete, an accumulator is installed in the hydraulic circuit in which a switching valve for operation on the gate valve side is provided. The accumulator is branched and connected to the hydraulic circuit, and when the hydraulic pressure in the hydraulic circuit becomes high, the gas sealed in the accumulator is compressed and pressure oil is automatically filled in the accumulator. Hydraulic oil with the same oil pressure as in the hydraulic circuit is stored and pressured. When the oil pressure in the hydraulic circuit becomes low, the high-pressure hydraulic oil accumulated in the accumulator is automatically reduced due to the air pressure in the accumulator. A general-purpose type is used which has the function of increasing the hydraulic pressure in the circuit by flowing into the same hydraulic circuit, and the hydraulic circuit is switched to the low-pressure side chamber of the gate cylinder by the switching valve for operating the gate valve. The sudden drop in oil pressure in the hydraulic circuit on the gate cylinder side at the beginning of switching is compensated for by the automatic supply of high-pressure oil from the accumulator, and the switching operation of the gate valve is performed at high speed together with the hydraulic oil supplied from the hydraulic supply source. It's well structured.

(Problems to be solved by the invention) In the hydraulic circuit with the accumulator of the conventional concrete pump, (1) The gate valve is stopped by the stopper at the end of the stroke due to the accumulator increasing the speed of the switching operation of the gate valve. When the collision occurs, the collision noise increases significantly, and the collision noise is directly emitted to the outside, resulting in a considerably loud operating noise and contributing to vibration generation.Even if the operating speed of the concrete pump is reduced, the action of the accumulator is There is no particular difference; the gate valve is always operated at high speed,
The operating noise and vibration cannot be reduced.

(2) Pressure is accumulated in the accumulator every time the switching valve is operated, and even when the concrete pump is operating at low speed, the gate valve is operated at an unnecessary high speed, resulting in wasted fuel consumption.

(3) Noise becomes a problem when working at night in residential areas, and even if the concrete pump is operated at a low speed, the operating noise and vibration caused by gate switching do not decrease, making it impossible to work.

(4) Since the gate valve is always operated at high speed, the gate valve wears out quickly, shortening its life and reducing work efficiency.

There are drawbacks such as.

(Purpose of the invention, means for solving problems) This invention relates to an invention to eliminate the above-mentioned drawbacks of conventional concrete pumps. a hydraulic cylinder side oil passage and a gate valve side oil passage;
A main hydraulic cylinder connected to the main hydraulic cylinder side oil passage via a sequence valve and a main hydraulic cylinder switching valve, a concrete pump driven by the main hydraulic cylinder, and a gate valve side oil passage connected via a gate cylinder switching valve. A connected gate cylinder, a gate valve that is driven by the gate cylinder and switches between suction and discharge of concrete in the concrete pump, and a gate valve side oil passage branching from the gate valve side oil path leading to the gate cylinder switching valve and connected via a gate valve. It is characterized in that it consists of an accumulator, a pilot oil passage branching from the gate valve side oil passage leading to the accumulator and connected to the pilot inlet of the sequence valve, and an on-off valve connected to the vent circuit of the sequence valve. The purpose of this is to install a gate valve at the outlet of the accumulator on the gate valve side and a sequence valve in the oil passage on the main hydraulic cylinder side in a concrete pump equipped with an accumulator to speed up the operation of the gate valve. An object of the present invention is to provide a hydraulic circuit for a concrete pump that can switch to a drive mode with less noise and vibration by using an on-off valve provided in the vent circuit of the concrete pump, and can save fuel consumption.

(Operations and effects of the invention) Since the present invention has the above-mentioned configuration, normally the gate valve can be switched at high speed by the action of the accumulator, so the concrete pump can be driven smoothly and at high efficiency, and the gate valve can be switched at high speed. When the accumulator is partitioned off to be inactive, and the opening/closing valve is used to open the vent circuit of the sequence valve in the oil passage on the main hydraulic cylinder side, leaving the sequence valve in the normally open state, the gate valve switching becomes slow and the gate valve side switching is activated. Noise and vibration are almost eliminated, and the oil pressure fluctuations in the gate valve side oil passage and the main hydraulic cylinder side oil passage are reduced, so the operating noise and vibration in both oil passages are also extremely small, resulting in an overall low noise and low noise.
It enables low-vibration pump drive and can be used for nighttime pouring work.

Therefore, damage to gate valves and oil passages is reduced.
It also saves fuel.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

In the figure, 1 is a hydraulic supply source, that is, a hydraulic pump,
A discharge oil passage 2 connected to a hydraulic pressure supply source 1 branches into a main hydraulic cylinder side oil passage 16 and a gate valve side oil passage 17, and a sequence valve 6 provided in the middle of the main hydraulic cylinder side oil passage 16 and a main hydraulic cylinder switching The two main hydraulic cylinders 19, 19 installed side by side are connected via the valve 15 so that they stroke in opposite directions, and the two concrete pumps A, A installed side by side are connected to each other for suction/discharge through the pistons of both hydraulic cylinders 19, 19. It is designed to travel in the opposite direction.

On the other hand, a gate cylinder switching valve 12 is provided in the middle of the gate valve side oil passage 17, and the gate valve 1 alternately opens and closes both the suction ports of the two concrete pumps A, A.
4 and another gate valve 14 that alternately opens and closes both discharge ports.
is provided at both ends of both gate valves 14, 14 so as to open the suction port and close the discharge port of one concrete pump A in the suction stroke, and close the suction port and open the discharge port of the other concrete pump A in the discharge stroke. The gate cylinders 13, 13, 13, 13 are connected to the gate cylinder switching valve 12 described above.

Further, the gate valve side oil passage 17 leading to the gate cylinder switching valve 12 is provided with an accumulator 11 branched via the gate valve 10, and the gate valve side oil passage 17 leading to the accumulator 11 is branched to the sequence valve 6. A pilot oil passage 6' connected to the pilot inlet of the sequence valve 6 is provided, and an on-off valve 8 is connected to the vent circuit 6'' of the sequence valve 6.

Further, a main relief valve 3 is provided in the discharge oil passage 2 connected to the hydraulic pressure supply source 1, and a switching valve 4 is provided in its vent circuit to switch between unloading and on-loading of the main relief valve 3. . Note that the gate cylinder switching valve 12 and the main hydraulic cylinder switching valve 15 can be operated by an appropriate switching mechanism (description omitted). Further, the opening/closing valve 8 and the gate valve 10 of the sequence valve are not limited to the front, but may be an electromagnetic switching valve, and any mechanism that can open and close the circuit can be applied. An electromagnetic switching valve is used for the on-off valve 8 of the sequence valve and the gate valve 10 of the accumulator.
By operating the ON/OFF switch on the concrete pump operation panel, you can easily select whether to activate or stop the accumulator at any time without leaving the operation panel. In the figure, 18 is a return tank.

Next, the operation of the above embodiment will be explained. In the illustrated state, when the gate valve 10 is fully opened and the hydraulic pressure supply source 1 is driven, the discharged pressure oil flows from the discharge pipe 2 through the main relief valve 3 and the tank return pipe. 5
The entire amount returns to the oil tank 18. Next, when the vent circuit 4 is energized, the vent circuit of the main relief valve 3 is closed and the main relief valve 3 is closed, and the pressure oil is sent to the concrete pump circuit side through the discharge pipe 2 and the pump is operated. . Initially, the sequence valve 6 is "closed" because no pressure is accumulated in the accumulator 11, and the pressure oil is in the check valve 9.
from the gate cylinder switching valve 12 to the gate cylinder 13, and both gate valves 14, 14 are placed in the illustrated position, and the inside of the gate valve side oil passage 17 becomes high pressure with the hydraulic pressure supplied from the hydraulic pressure supply source 1, and the gate valve side The operating shaft flows into the accumulator 11 from the oil passage 17 through the gate valve 10 (by compressing the gas sealed in the accumulator 11), and the accumulator 11
As the pressure of the gas increases, the increased pressure of the operating shaft in the accumulator 11 reaches the same high pressure as the oil pressure in the gate valve side oil passage 17 and is accumulated. When the internal pressure of the accumulator 11 exceeds the set pressure of the sequence valve 6, the sequence valve 6 is opened and pressure oil is sent to the main hydraulic cylinder 19 through the sequence valve 6, check valve 7, and main hydraulic cylinder switching valve 15. , both cylinders 1
9 and 19 as shown in the figure, the upper concrete pump A performs the discharge stroke, and the lower concrete pump A performs the suction stroke. When the main hydraulic cylinder reaches top dead center, the gate cylinder switching valve 12 is switched by a mechanism not shown, and the gate valve side oil passage 17 is connected to the low pressure side chamber of the gate cylinder 13 (because it communicates with the return tank 18). Since the oil pressure on the same side of the gate valve side oil passage 17 decreases due to communication,
Pressure oil stored in the accumulator 11 passes through the gate valve 10 and the gate cylinder switching valve 12 and is discharged to the gate cylinders 13 .
4 is rapidly switched in the opposite direction, and as a result of the increase in oil pressure in the gate valve side oil passage 17, pressure is accumulated in the accumulator 11 as described above. Next, when the main hydraulic cylinder switching valve 15 is switched, the accumulator 11
After the pressure is accumulated in the pump, the sequence valve 6 is opened, and the main hydraulic cylinders 19, 19 operate in the opposite direction to the above, the upper concrete pump A enters the suction stroke, and the lower concrete pump A discharges. This becomes a stroke, and by repeating the above operation, a normal pump action is achieved.

Furthermore, when the on-off valve 8 provided in the vent circuit 6'' of the sequence valve 6 is switched from the illustrated state, the vent circuit 6'' is communicated with the oil tank 18, and the pressure accumulated in the accumulator 11 is controlled by the pilot oil passage 6'. Regardless, the sequence valve 6 is always “open”,
When the gate valve 10 is fully closed, there is no accumulation of pressure in the accumulator 11 and no discharge from it, so the gate valve 14 is switched only by the pressure oil supplied from the discharge oil path 2, and the same pressure oil is always supplied to the main hydraulic cylinder side. Therefore, by switching the gate cylinder switching valve 12 and the main hydraulic cylinder switching valve 15, both concrete pumps A, A can be driven alternately in the suction and discharge strokes.

Therefore, when the pump is driven as described above when the sequence valve 6 is fully opened by communicating the vent circuit 6'' through the on-off valve 8 and the accumulator 11 is made inoperable by fully closing the gate valve 10, the accumulated pressure in the accumulator 11 is reduced. Since it is not added to the gate valve side oil passage 17, the gate valves 14, 14 are switched only by the hydraulic pressure supplied from the discharge pipe 2 side, and the operating noise and vibration caused by switching the gate valve 14 are almost eliminated. Fuel consumption equivalent to the pressure accumulated in the tank is saved, and damage to the gate valve 14 is also reduced. Calculation using a mathematical formula shows that when the accumulator is operating, the switching operation speed of the gate valve is lower than when the accumulator is not operating. It has been established that the speed of the motor is increased several times and that the operating noise is therefore also significantly increased in proportion to said speed increase.

Furthermore, since there is no oil pressure supplied from the accumulator 11, the oil pressure fluctuation in the gate valve side oil passage 17 is small, and since there is no switching operation of the sequence valve in the main hydraulic cylinder side oil passage 16, there is no oil pressure fluctuation due to it. The operating noise and vibrations of both oil passages 16 and 17 have become extremely small, the operating speed of concrete pumps A and A has been reduced, and the opening and closing operations of on-off valves 8 and gate valves 10 have enabled quiet pump drive as a whole. This reduces fuel consumption and damage to gate valves, oil passages, etc.

[Brief explanation of drawings]

The figure is an explanatory diagram of the hydraulic circuit of the concrete pump of the present invention. 1: Hydraulic supply source (hydraulic pump), 2: Discharge oil path, 6: Sequence valve, 6': Pilot oil path,
6″: Vent circuit, 7, 9: Check valve, 8: Open/close valve, 10: Gate valve, 11: Accumulator, 1
2: Gate cylinder switching valve, 13: Gate cylinder, 14: Gate valve, 15: Main hydraulic cylinder switching valve, 16: Main hydraulic cylinder side oil passage, 17: Gate valve side oil passage, 19: Main hydraulic cylinder, A: concrete pump.

Claims (1)

[Scope of utility model registration request] A discharge oil path connected to a hydraulic pressure supply source, a main hydraulic cylinder side oil path and a gate valve side oil path branched from the discharge oil path, and a sequence valve and a main hydraulic cylinder switching valve to the main hydraulic cylinder side oil path. A connected main hydraulic cylinder, a concrete pump driven by the main hydraulic cylinder, a gate cylinder connected to the gate valve side oil passage via a gate cylinder switching valve, and a concrete pump driven by the gate cylinder. A gate valve for switching suction/discharge, an accumulator branched from a gate valve side oil path leading to the gate cylinder switching valve and connected via a gate valve, and a sequence valve branched from the gate valve side oil path leading to the accumulator. A hydraulic circuit for a concrete pump, comprising a pilot oil passage connected to a pilot inlet of the concrete pump, and an on-off valve connected to a vent circuit of the sequence valve.