JPS60125780A - High and low pressures automatic switching device of concrete pump - Google Patents

Abstract

PURPOSE:To improve the capacity of pressure sending by a method wherein the pressure sending mode with respect to the concrete is switched automatically into low pressure-high speed or high pressure-low speed in accordance with the condition or the like of the concrete. CONSTITUTION:When ready mixed concrete is soft and the forward surface pressures of concrete pressure sending pistons 2, 2 are small, both hydraulic cylinders 3, 4 for both pumps are switched automatically and are operated in the low output-high speed mode, therefore, a large amount of concrete is sent by a low pressure. Supposed the necessary pressure sending force is increased due to some reason, both hydraulic cylinders 3, 4 for pumps are switched automatically and are operated under the high output-low speed mode, therefore, the small amount of concrete is sent by a high pressure thereby operating so as to match the demand.

Description

[Detailed Description of the Invention] Technical Field> This invention relates to a high and low pressure automatic UL arrangement contract for a concrete pump. <Prior Art> In general, a concrete pump drives a pair of pistons for pumping concrete. Equipped with a pair of pump hydraulic cylinders. There are two types of drive devices for the pair of pump hydraulic cylinders. - the drive device is
The base chambers of the pair of pump hydraulic cylinders are communicated with each other, and a tip chamber of one of the pump hydraulic cylinders,
In other words, a pressure source is connected to the chamber on the piston rond side to supply hydraulic oil. In this drive device, high-pressure hydraulic oil is supplied from the pressure source to the tip chamber of the pump hydraulic cylinder, so the pressure receiving area of the piston of the pump hydraulic cylinder is reduced by the piston rod, and the pump The operating speed of the concrete hydraulic cylinder increases, and the amount of concrete discharged increases, but the output decreases and the front pressure of the concrete pumping piston becomes low, causing the problem that concrete cannot be pumped at high pressure. be. That is, the characteristic curve of this drive device is as shown in FIG. On the other hand, another driving device has the tip chambers of a pair of pump hydraulic cylinders communicated with each other, and one of the pump hydraulic cylinders has a pressure source connected to the base chamber to supply hydraulic oil. It is something. In this drive device, high-pressure hydraulic oil is supplied from the pressure source to the base chamber, so the pressure receiving area of the pump hydraulic cylinder becomes large, resulting in a large output.
The front pressure of the concrete pumping piston increases,
Concrete can be pumped under high pressure, but there is a problem in that the operating speed of the hydraulic cylinder for the pump becomes slow and the amount of concrete discharged decreases. That is, the characteristic curve of this drive device is as shown in FIG.

In summary, the former drive device pumps concrete at low pressure and high speed, so it cannot be used for concrete that needs to be pumped at high pressure, and the latter drive device
Concrete is pumped at high pressure and low speed, so even if concrete can be pumped at low pressure, the pumping speed is slow and there is a problem in that the operating efficiency is reduced.

<Object of the Invention> Therefore, the object of the present invention is to provide a concrete pump that improves the pumping capacity by automatically switching the pumping mode F for concrete to low-pressure high-speed or high-pressure low-speed depending on conditions such as the state of concrete. The purpose of the present invention is to provide automatic high/low pressure switching equipment.

<Configuration and operation of the invention> In order to achieve the above object, the configuration of the present invention is to form a first line that connects the base chambers of a pair of pump hydraulic cylinders with each other at one position, and to A second line is formed to connect the tip chambers of the pump hydraulic cylinders to a pressure source, and a second line is formed at the other position to connect the tip chambers of the pair of pump hydraulic cylinders to each other. A control valve that connects a base chamber of the hydraulic cylinder to a pressure source; a control line that guides the load pressure of the pump hydraulic cylinder to a pilot chamber of the control valve; and a sequence valve interposed in the control line. It has the following characteristics.

The operation of the present invention is such that when the required repulsive force for pumping the concrete sheet is low, the sequence valve closes and the control valve is positioned at one switching position, so that one of the hydraulic cylinders for the pump is switched on. High-pressure hydraulic oil is supplied from a pressure source to the tip chamber, and the hydraulic cylinder for the pump is operated at low output and high speed, and the concrete pump is operated at low pressure and high speed depending on the condition of the concrete, while at the same time pumping the concrete as required. When the pressure is high, the sequence valve opens and the control valve is placed in the other switching position to supply high-pressure hydraulic oil from the pressure source to the base chamber of one of the pump hydraulic cylinders. The hydraulic cylinder for the pump is operated at high output and low speed, and the concrete pump is operated at high pressure and low speed depending on the condition of the concrete.

<Example> Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

In Fig. 3, 1 is a pair of concrete pressure pump cylinders, 3.4 is the concrete pressure pump piston 2,
2 is a pair of pump hydraulic cylinders that drive the pump hydraulic cylinders 3 and 4; 5 is a pressure source such as a hydraulic pump; 6 is connected between the pressure source 5 and the pump hydraulic cylinders 3 and 4;
This is a forward/reverse switching valve that controls six operations.

A control valve 11 having two positions V, V2 is connected between the forward/reverse switching valve 6 and the pump hydraulic cylinder 3.4. The control valve 11 is positioned at position V1 by a bias spring 13 during normal operation. Boats Y and M of the control valve 11 are boats A of the forward/reverse switching valve 6, respectively.

Connect to B. Bows X and Z of the control valve 11 are connected to the base chamber 4a and tip chamber 4b of the pump hydraulic cylinder 4, respectively. Further, the bows L and N of the control valve 11 are respectively the base chamber 3a and the tip chamber 31 of the pump hydraulic cylinder 3.
]. The control valve 11 is in position (3),
Connect ports M and N, boats Y and Z, and ports X and L, respectively, and on the other hand,
J LVI-kA port) Z and N are connected to each other.

Therefore, the control valve 11 forms a first line>'35.15 that communicates the base chamber 3a of the pump hydraulic cylinder 3 with the base chamber 4a of the pump hydraulic cylinder 4 at one position V1, and at the other position V1. At V2, the tip chamber 3b of the pump hydraulic cylinder 3 and the tip chamber 4 of the pump hydraulic cylinder 4
A second line 16.16 is formed which communicates with b.

The control line 21 connects the power line 15 between the port Connecting. "1" In the middle of the control line 21, "1
Sequentially from the line 15 side, check valve 22, sequence valve 23. A second throttle valve 24 is provided. The control line 21 between the sequence valve 23 and the check valve 22 is provided with a control line 26 having a check valve 25 in the middle.
A line 15 between the port L of the control valve 11 and the base chamber 3a of the pump hydraulic cylinder 3 is connected. Furthermore, a line 3 having a first throttle valve 31 in the middle is added to the control line 21 between the sequence valve 23 and the second throttle valve 24.
A tank 33 is connected via 2.

The concrete pump automatic high-low pressure switching device configured as described above operates as follows.

Now, assume that the concrete pump is started with the control valve 11 in its normal position (position 1), and that the fresh concrete to be pumped is soft and the front pressure of the concrete pumping pistons 2, 2 is small.

Then, as shown in FIG.
It is supplied to the tip chamber 4b of the pump hydraulic cylinder 4 through the ports Y and Z. In this way, when hydraulic oil is supplied to the tip chamber 4a, the piston 4C of the pump hydraulic cylinder 4 has a small pressure receiving area corresponding to the piston rod 4d, so the pump hydraulic cylinder 4 has an output is small but operates at high speed. The hydraulic oil discharged from the base chamber 4a of the pump hydraulic cylinder 4 is supplied to the base chamber 3a of the pump hydraulic cylinder 3 through the first line Is, 15.
The hydraulic cylinder for the pump also operates at the same speed as 1.

Therefore, the hydraulic syringes 3.4 for both pumps will operate in a low power, high speed mode to pump a large amount of concrete at low pressure, meeting the requirements.

On the other hand, at this time, the control line 21 and the check valve 22
a first line 15 acting on the sequence valve 23 through
In other words, the pressure corresponding to the load pressure of the pump hydraulic cylinders 3 and 4 is low pressure, so the sequence valve 23
remains closed, no hydraulic oil pressure acts on the pilot chamber 18 of the control valve 11, and the control valve 11 is at the normal position vI.
remains located. Therefore, the low power, high speed operating mode of Schilling 1,5 for both pumps is retained.

Next, suppose that the required concrete pumping force becomes large for some reason. Then, the control valve 23
Since the pressure in the first line 15 acting on the control valve becomes high, the sequence valve 23 automatically opens, and the pressure in the first line 15, that is, the pressure corresponding to the load pressure, is applied to the pilot chamber 18 of the control valve 11. As a result, control valve 11 is automatically placed in position a V 2 . Then, the control valve 11
Port)N and Z of the control valve 11 are connected to form a second line 16.16, and the hydraulic oil from the pressure source is supplied to the port)Y of the control valve 11.
, L, and is supplied to the base chamber 3a of the pump hydraulic cylinder 3. This base chamber 3a includes a piston rod 3d.
Since there is no pressure, the pressure receiving area of the piston 3c is large, and the pump hydraulic cylinder 3 operates at low speed but high output. The hydraulic oil discharged from the tip chamber 3b of the pump hydraulic cylinder 3 is transferred to the second line 16. i6, and is supplied to the tip chamber 41 of the pump hydraulic cylinder 4,
The pump hydraulic cylinder 4 also operates at the same speed as the pump hydraulic cylinder 3. Therefore, the hydraulic cylinders 3 and 4 for both pumps will compress a small amount of concrete at high pressure in high output and low speed mode, and must operate in accordance with the requirements. become. Note 1. At this time, the control line 26 is connected to the pilot chamber 18 of the control valve J1.
Hydraulic oil is supplied through a check valve 25, a sequence valve 23, and a second throttle valve 24.

Next, in this state, if the required pressure for pumping concrete decreases, the sequence valve 23 will automatically close, and the hydraulic fluid in the pilot chamber 18 of the control valve 11 will flow through the second throttle valve 24 and 1 through the throttle valve 31, tank 3
3, the control valve 11 automatically returns to the false position by the spring force of the spring 13, and the pump hydraulic cylinder 3
, 4 in low power, high speed mode.

In this way, the high-low pressure automatic switching device of this concrete pump automatically switches the concrete pumping mode to low-pressure high-speed or high-pressure low-speed depending on conditions such as the condition of the concrete, improving the concrete pumping capacity. It can be done. The above-mentioned pumping mode is now shown by the thick solid line ■ in Figure 4, and by combining the conventional characteristic curve 1 and the characteristic curve in Figure 2, the one in Figure 2 is used for high pressure and low speed, and the first characteristic curve is used for low pressure and high speed.
This is the one shown in the figure.

The second throttle valve 24 is intended to slow down the response of the control valve 11 to pressure fluctuations in a spool (not shown), thereby preventing hunting or the like.

FIG. 5 shows a modification in which an electromagnetic pilot switching valve 41 is provided in place of the first throttle valve 31 shown in FIG. 3, and the valve is in the normal position S when not in operation. The control valve 11 is placed at the switching position SI to perform pressure relief, and is energized during operation to be placed at the switching position SI to operate the control valve 11 in accordance with the load pressure. In the apparatus shown in FIG. 5, the same components as those in the apparatus shown in FIG. 4 are given the same reference numerals, and the description thereof will be omitted.

Although not shown, the first throttle valve 31 shown in FIG. 3 and the electromagnetic pilot switching valve 41 shown in FIG.
You may make it branch toward the tank 33 in parallel from the downstream of 3.

<Effects of the Invention> As is clear from the above explanation, according to the present invention, the pumping mode for concrete is automatically switched to low pressure high speed or high pressure low speed depending on the condition of the concrete etc. You can improve your abilities to +11.

[Brief explanation of the drawing]

Figures 1 and 2 are characteristic diagrams showing the pumping capacity of a conventional concrete pump, Figure 3 is a circuit diagram of an embodiment of the present invention, and Figure 4 is a diagram showing the pumping capacity of a conventional concrete pump.
The figure is a characteristic diagram of the above embodiment, and FIG. 5 is a circuit diagram of a modified example. 3,・1... Hydraulic cylinder for pump, 3a, 4a...
- Base chamber, 311, 411... Tip chamber, 5... Pressure source, 11... Control valve, 15... First line, 16.
...Second line, 21.26...Control line, 23...
・Sequence valve. Patent Applicant: Kyokuto Kaihatsu Kogyo Co., Ltd. Agent: Patent Attorney: Aohaku Ao and 2 others Figure 1 Figure 4 Figure 2

Claims (1)

[Claims] (1) - Forming a first line that communicates the base chambers of the pair of pump hydraulic cylinders with each other at the force position, and
While connecting the tip chambers of one of the pump hydraulic cylinders to a pressure source, a second line is formed at the other position to connect the tip chambers of the pair of pump hydraulic cylinders with each other, and one of the pump hydraulic cylinders is connected to a pressure source. a control valve that connects the base chamber of the hydraulic cylinder for the pump to a pressure source; a control line that guides the load pressure of the hydraulic cylinder for the pump to the pilot chamber of the control valve; and a sequence valve interposed in the control line. An automatic high-low pressure switching device for a concrete pump, characterized by comprising: