JPH0338430B2 - - Google Patents

Description

Detailed Description of the Invention <Industrial Application Field> The present invention provides a concrete system that can reduce vibrations and noise generated when sucking and pumping ready-mixed concrete by driving a concrete pump and valve cylinder according to the condition of the ready-mixed concrete. The present invention relates to a pump sequence drive device.

<Prior art> As a conventional concrete pump sequence drive device, as shown in Fig. 4, a hydraulic pump 1 is used.
When the pressure oil from the accumulator 2 is accumulated in the accumulator 2 and the pressure in the accumulator 2 exceeds the set pressure of the sequence valve 4, the sequence valve 4 is activated and the hydraulic oil is transferred to the hydraulic pump 1 via the sequence valve 4 and the main cylinder control switching valve 5. Pressure oil from is supplied to one main cylinder 6, and this main cylinder 6 operates to pump fresh concrete from one concrete pump 8, and at the same time,
Fresh concrete is sucked into the other concrete pump 8 through the valve 9, and then the valve control switching valve 1
1 is switched, the pressure oil in the accumulator 2 is suddenly supplied to the valve cylinder 12 via the valve control switching valve 11, the valve 9 is switched instantaneously, and the pressure in the accumulator 2 is switched to the sequence valve again. When the set pressure of 4 is reached, the main cylinder 6
There are pumps that operate to suck fresh concrete into one concrete pump 8 through a valve 9, and at the same time pump the fresh concrete from the other concrete pump 8.

<Problems to be Solved by the Invention> However, in the concrete pump sequence drive device, since the valve 9 is switched at high speed and high pressure using the accumulator 2 every time the valve 9 is switched, vibrations and vibrations occur during the switching. There is a problem with noise. Moreover, since the switching of the valve 9 is performed by reciprocating the piston 14 in the valve cylinder 12 at high speed and high pressure using pressure oil from the hydraulic pump 1 and pressure oil from the accumulator 2, the piston 14 There is a problem in that severe wear occurs on the sliding parts of the valve 9 and the contact surface of the valve 9.

Therefore, the purpose of this invention is to reduce the number of times the accumulator is used, and to reduce the number of times the accumulator is used, by not using the accumulator when pumping ordinary ready-mixed concrete using low pressure, and only when pumping ready-mixed concrete with a poor mix using high pressure. The aim is to reduce the number of times and also reduce the amount of wear that occurs on valves and valve housings.

<Structure of the Invention> In order to achieve the above object, the sequence drive device for a concrete pump of the present invention includes a main cylinder connected to a hydraulic pump via an oil path to drive the concrete pump, and a third cylinder for controlling the main cylinder. a position switching valve; a concrete valve that switches between sucking and pressurizing fresh concrete in the concrete pump; a valve cylinder that is connected to a hydraulic pump via an oil path to control the concrete valve and drives the concrete valve; and the hydraulic pump. and an accumulator disposed in an oil path between the valve cylinder and the valve cylinder, an accumulator selection switch for selecting whether or not to use the accumulator, and an accumulator in the accumulator selection switch When the fluid pressure in the oil line connected in series with the operating side contact and leading to the accumulator is lower than the accumulator setting pressure, the main cylinder control valve 3 is turned off.
The position switching valve is held in a neutral position to accumulate pressure oil in the accumulator, and when the fluid pressure in the oil passage exceeds the set pressure of the accumulator, it is turned on and switches the main cylinder control switching valve to the operating position. and a pressure switch that causes pressure oil to be fed from the accumulator to the valve cylinder.

<Examples> The present invention will be described in detail below with reference to illustrated examples.

As shown in FIG. 1, logic valves 25a, 25b, 25c, and 25d are connected to a valve cylinder 26a between a high pressure line 22a connected to the outlet of the hydraulic pump 21 and a low pressure line 22b connected to the tank 24. , 26b are connected. The valve cylinders 26a, 26b and the hydraulic pump 21
The high pressure line 22a between the accumulator 2
There are 8. A check valve 29 is provided between the accumulator 28 and the hydraulic pump 21, and the check valve 29 prevents the pressure oil accumulated in the accumulator 28 from flowing back. Main cylinder logic valves 31a, 31b, 31c, 31 are connected between the high pressure line 22a and the low pressure line 22b between the check valve 29 and the hydraulic pump 21.
The main cylinders 32 and 42 are connected via d. As shown in FIG. 2, a cylindrical concrete pump 34 having a larger diameter than the main cylinder 32 is connected to the main cylinder 32, and the main cylinder 32 causes a piston 34a of the concrete pump 34 to reciprocate. . Another main cylinder 42 and concrete pump 4 having the same structure as the above main cylinder 32 and concrete pump 34
4, the other ends of the main cylinders 32, 42 are connected to each other by a connecting passage 35, and one ends of the concrete pumps 34, 44 are connected to the outlet of a concrete hopper (not shown). A valve 36 is provided at the outlet. Then, by opening and closing the valve 36, the concrete pump 34,
The fresh concrete in the concrete hopper is sucked into the concrete hopper 44, and the suction is stopped. Further, as shown in FIG. 1, the main cylinder control pilot switching valve 38 is a three-position switching valve, and
The pilot chambers 38a, 38b at both ends are connected to the pilot line 3 to the valve cylinders 26a, 26b.
9 and 41 respectively, the valve cylinders 26a and 26b operate to the end of their stroke and increase pressure, thereby switching from the neutral position to a predetermined symbol position.
2 and 42 are controlled. In addition, the 3-position switching valve 45 for main cylinder control is connected to the high pressure line 22a.
It is connected between the low pressure line 22b and the main cylinder control pilot switching valve 38, and controls the operation of the main cylinders 32,42. Further, the valve control pilot switching valve 46 is a two-position switching valve, with pilot chambers 46a and 4 located at both ends thereof.
6b are connected to main cylinders 42 and 32 via logic valves 48 and 49, respectively. A pilot line 51 between the valve control pilot switching valve 46 and the high pressure and low pressure lines 22a and 22b,
52 is connected to a switching valve 54 for valve control.
The valve control switching valve 54 is a three-position switching valve, and controls the opening and closing of the valve 36. The valve control switching valve 54 and the high pressure and low pressure lines 22a,
A pressure switch PS is connected between the pilot line 51 and the pilot line 52. Note that 70, 70, and 70 are check valves, and 71 is a relief valve.

Contact PS ₁ of the pressure switch PS is provided in a relay circuit shown in FIG. 3 in a control panel (not shown). That is, in the relay circuit, the power line 61a and the common contact C1 of the accumulator selection switch 62 are connected, and the relay coil R1 is connected between the accumulator non-operating side contact B of the accumulator selection switch 62 and the power line 61b, A contact PS 1 of a pressure switch PS is connected between a connection point ₆₄ between the relay coil R1 and an accumulator non-operating contact B and an accumulator operating contact A of an accumulator selection switch 62.

In addition, while connecting the power line 61a and the common contact C2 of the concrete pump drive switch 65, a relay coil _R3 is connected between the normal rotation side contact E of the concrete pump drive switch 65 and the power line 61b, and the concrete Reverse side contact F of pump drive switch 65 and power line 61b
Relay coil R2 is connected between.

Further, a relay contact r2 and one coil S3 of the valve control switching valve 54 are connected in series between the two power supply lines 61a and 61b. The connection point 66 between the relay contact r2 and the coil S3 and the power line 61b are connected to the relay contact r1 and one coil S of the three-position switching valve 45 for controlling the main cylinder.
2 are connected in series, while the relay contacts r3 and r1 are connected in three positions for main cylinder control between the connection point 68 between the relay contact r2 and the power line 61a and the power line 61b. The other coil S1 of the switching valve 45 is connected in series. Furthermore, the relay contact r3 and the relay contact r
The other coil S4 of the valve control switching valve 54 is connected between the connection point 69 between the valve control valve 1 and the power supply line 61b.

In the concrete pump sequence drive device configured as described above, first, when ordinary ready-mixed concrete is sucked and pumped by the concrete pumps 34 and 44, it is necessary to use the accumulator 28 because ordinary ready-mixed concrete has a high moisture content and is easy to pump. Therefore, the common contact C1 of the accumulator selection switch 62 of the relay circuit shown in FIG. 3 is connected to the accumulator non-operating contact B. Relay coil R1
is excited and relay contact r1 is turned on. on the other hand,
In order to cause the concrete pumps 34, 44 to rotate in the normal direction, the common contact C2 and the normal rotation side contact E of the concrete pump drive switch 65 are connected. Relay coil R3 is energized and relay contact r3 is turned on. As a result, one coil S1 of the three-position switching valve 45 for controlling the main cylinder is excited, and one coil S4 of the switching valve 54 for valve control is excited. As shown in FIG. 1, the three-position switching valve 45 for main cylinder control switches from the neutral position, that is, the normal position Vo, to the symbol position V1, while the valve control switching valve 54 switches from the normal position to the symbol position V4. Switch to . At this time, the pressure oil discharged from the hydraulic pump 21 is transferred to the high pressure line 2.
2a, and this high pressure is transmitted through the pilot line 51 to the valve control switching valve 54 located at the symbol position V4. On the other hand, since the valve control pilot switching valve 46 has been switched to symbol position V5, the high pressure is applied to the pilot line 51, the valve control switching valve 54 at symbol position V4, and the valve control pilot switching valve at symbol position V5. Logic valves 25a and 2 for the first and third valves from the upstream side in the figure are connected via the valve 46.
It is transmitted to the spring chambers S, S of 5c. Then, the logic valves 25a and 25c are closed.
On the other hand, the spring chambers S and S of the logic valves 25b and 25d for the second and fourth valves from the upstream side in the figure are the pilot switching valve 46 for valve control located at the symbol position V5, and the switching valve for valve control located at the symbol position V4. 54. Since it communicates with the low pressure line 22b via the pilot line 52, the valve logic valves 25b and 25d are opened. As a result, high pressure oil in the high pressure line 22a is supplied to the valve cylinder 26b via the valve logic valve 25d, the valve cylinders 26a and 26b are operated, and the valve 36 is switched. When the valve cylinder 26b operates to the end of its stroke, the pressure in the valve cylinder 26b becomes approximately as high as the discharge pressure of the hydraulic pump 21, so this high pressure is passed through the pilot line 41 to the main cylinder control pilot switching valve. 38 pilot compartment 38b
, the main cylinder control pilot switching valve 38 is switched from the normal position to the symbol position V6. As mentioned above, 3 for main cylinder control
Since the position switching valve 45 has been switched to the symbol position V1, the high pressure pilot line 81 from the high pressure line 22a, the three-position switching valve 45 for main cylinder control located at the symbol position V1, and the symbol position V
Main cylinder control pilot switching valve 38 located at 6
through the spring chambers S, S of the second and fourth main cylinder logic valves 31b, 31d from the upstream side in the figure.
can be conveyed to. Then, the main cylinder logic valves 31b and 31d are closed. On the other hand, the spring chambers S and S of the first and third main cylinder logic valves 31a and 31c from the upstream side in the figure are at the symbol position V.
Pilot switching valve 3 for main cylinder control located at 6
8. The main cylinder control three-position switching valve 45 located at the symbol position V1 is connected to the low pressure line 22b via the pilot line 82, so the main cylinder logic valves 31a and 31c are opened. As a result, high pressure oil from the high pressure line 22a is supplied to the main cylinder 32 via the main cylinder logic valve 31a, and the piston 34 shown in FIG.
a, 44a are activated to suck fresh concrete into the concrete pump 34 via the valve 36, while pumping the fresh concrete from the concrete pump 44.

Next, when concrete pumps 34 and 44 are sucking in and pumping fresh concrete with a poor mix that is difficult to pump and contains a lot of aggregate with little moisture, the set pressure of the pressure switch PS is set to 120 kg/cm ² . shall be. Then, the discharge pressure of the hydraulic pump 21 is 120
Kg/cm ² or less, the common contact C1 of the accumulator selection switch 62 of the relay circuit shown in FIG.
Even if the contact A on the accumulator operating side is connected,
Since the set pressure of pressure switch PS is set to 120Kg/ ^cm2 , relay coil R1 is not energized and relay contact r1 is turned off because contact PS ₁ of pressure switch PS does not turn on. The coil S1 in one pilot chamber 45a of the three-position switching valve 45 for controlling the main cylinder is de-energized.
Common contact of concrete pump drive switch 65
Since _C2 is connected to the normal rotation side contact E, the relay coil R3 is energized, the relay contact r3 is turned on, and the relay S4 in the pilot chamber 54a on one side of the valve control switching valve 54 is energized. It will remain as it is. As a result, the three-position switching valve 45 for main cylinder control switches from the symbol position V1 to the normal position Vo, while the valve control switching valve 54 is held at the symbol position V4. Furthermore, since the main cylinder control pilot switching valve 38 is held at the symbol position V6 as described above, the high pressure line 2
The high pressure from 2a is transmitted to all the main cylinder logic valves 31a through the pilot line 81, the 3-position switching valve 45 for main cylinder control located at the normal position Vo, and the pilot switching valve 38 for main cylinder control located at the symbol position V6. , 31b, 31c,
31d to the spring chambers S, S, S, S, and the main cylinder logic valves 31a, 31b, 31
c, 31d are closed. And hydraulic pump 21
The pressure oil discharged from the main cylinders 32 and 42 is not supplied to the main cylinders 32 and 42, and the main cylinders 32 and 42 are in a stopped state, and the pressure oil is accumulated in the accumulator 28. Then, the discharge pressure of the hydraulic pump 21 is 120
When the pressure exceeds Kg/cm ² , the contact PS ₁ of the pressure switch PS shown in Fig. 3 turns on, so the relay coil R1 is energized and the relay contact r1 turns on.
Since the common contact C2 of the concrete pump drive switch 65 is connected to the normal rotation side contact E, the relay coil R3 is energized and the relay contact r3 is turned on to switch one side of the three-position switching valve 45 for main cylinder control. coil S1 is excited, while one coil S4 of the valve control switching valve 54 remains excited. As a result, the three-position switching valve 45 for controlling the main cylinder changes from the normal position Vo to the symbol position V1.
On the other hand, the valve control switching valve 54 is held at the symbol position V4. As a result, the high pressure of the high pressure line 22a passes through the pilot line 51 and passes through the valve control switching valve 54 located at the symbol position V4 and the valve control pilot switching valve 46 located at the symbol position V5. This is transmitted to the spring chambers S, S of the third logic valves 25a, 25c, and the logic valves 25a, 25c are closed. On the other hand, logic valves 25 for the second and fourth valves from the upstream side in the figure
The spring chambers S and 25d communicate with the low pressure line 22b via the valve control pilot switching valve 46 located at the symbol position V5, the valve control switching valve 54 located at the symbol position V4, and the pilot line 52, so that the above-mentioned valves logic valve 25b, 25
d is open. For this reason, the pressure oil accumulated in the accumulator 28 is immediately transferred to the valve logic valve 25.
d to the valve cylinder 26b, and the valve 36 is switched at high speed.

On the other hand, as described above, one coil S1 of the 3-position switching valve 45 for main cylinder control is energized, and the 3-position switching valve 45 for main cylinder control is in the normal position.
While switching from Vo to symbol position V1,
The high pressure in the valve cylinder 26b is applied to the pilot chamber 3 of the main cylinder control pilot switching valve 38.
8b, the main cylinder control pilot switching valve 38 is switched to the symbol position V6. Further, the high pressure from the high pressure line 22a is transferred to the upstream side in the figure via the pilot line 81, the 3-position switching valve 45 for main cylinder control located at the symbol position V1, and the pilot switching valve 38 for main cylinder control located at the symbol position V6. This is transmitted to the spring chambers S, S of the second and fourth main cylinder logic valves 31b, 31d, and the main cylinder logic valves 31b, 31d are closed, while the first and third main cylinder logic valves 31b, 31d from the upstream side in the figure are closed. Logic valve 31 for main cylinder
The spring chambers S and S of a and 31c are connected to the low pressure line 22a via a pilot switching valve 38 for controlling the main cylinder located at the symbol position V6, a 3-position switching valve 45 for controlling the main cylinder located at the symbol position V1, and a pilot line 82. Therefore, the main cylinder logic valves 32a and 32c are opened. The pressure oil from the main hydraulic pump 21 is supplied to the high pressure line 2.
2a, is supplied to the main cylinder 32 via the main cylinder logic valve 31a, and the pistons 34a, 44
b is activated and at the same time the concrete pump 34 sucks ready-mixed concrete into the concrete pump 4.
From step 4, the fresh concrete is pumped. This main cylinder 3
2 is transmitted via pilot line 84 to the spring chamber of logic valve 49, causing logic valve 49 to close. Also, concrete pump 4
When the piston 44a of No. 4 reaches the stroke end, the pressure inside the main cylinder 42 increases, and this high pressure flows through the pilot line 85 and the logic valve 4.
8 to the pilot chamber 46a of the valve control pilot changeover valve 46, and the valve control pilot changeover valve 46 is switched from the symbol position V5 to the symbol position V7. As a result, the valve logic valves 25b and 25d are closed. On the other hand, the valve logic valves 25a and 25c are opened. After the pressure oil from the hydraulic pump 21 is accumulated in the accumulator 28, the accumulated pressure oil is supplied at once to the cylinder valve 26a via the valve logic valve 25a. Valve 36 switches at high speed. On the other hand, the high pressure in the valve cylinder 26a passes through the pilot line 39 to the pilot chamber 38 of the main cylinder control pilot switching valve 38.
a, the main cylinder control pilot switching valve 38 changes from symbol position V6 to symbol position V.
Switch to 8. As a result, the main cylinder logic valves 31a and 31c are closed, while the main cylinder logic valves 31b and 31d are opened. and,
Pressure oil from the hydraulic pump 21 is supplied to the main cylinder 42 via the main cylinder logic valve 31d, and the pistons 34a and 44a shown in FIG. At the same time, the fresh concrete is pumped from the concrete pump 34.

In this way, the accumulator 28 is used only in the case of poorly mixed concrete that is difficult to pump.
Not only can the number of occurrences of vibration and noise generated from the valve 36 and the valve cylinders 26a, 26b when pressure oil is fed by the accumulator 28 be reduced, but also the amount of wear on the sliding parts of the valve cylinders 26a, 26b can be reduced. Furthermore, by making the set pressure of the pressure switch PS variable, the charge pressure of the accumulator 28 can be controlled, and it is possible to deal with fresh concrete of various poor mixes.

Further, when the ready-mixed concrete is to be pumped to a high place or a far place, the above-mentioned ready-mixed concrete can be pumped using the accumulator 28 in the same way as in the case of the above-mentioned poor mix of ready-mixed concrete.

<Effects of the Invention> As is clear from the above description, the concrete pump sequence drive device of the present invention includes a hydraulic pump, a main cylinder, a 3-position switching valve for controlling the main cylinder, a concrete valve, a valve cylinder, an accumulator, Furthermore, we have installed an accumulator selection switch that selects whether or not to use the accumulator, and a pressure switch that operates based on the relationship between the set pressure of the accumulator and the fluid pressure in the oil line, so that it is possible to use a poorly mixed concrete that is difficult to pump. The accumulator can be used only when pressure oil is pumped from a concrete pump, and it is possible to reduce the number of vibrations and noises generated from valves, valve cylinders, oil passages, etc. when pressure oil is pumped by the accumulator, and also to reduce the number of vibrations and noises generated from valves, valve cylinders, oil passages, etc. The amount of wear on the sliding parts of the valve and the contact surface of the valve can be reduced.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of the concrete pump sequence drive device of the present invention, Fig. 2 is a schematic diagram showing the main cylinder, concrete pump, and valve, and Fig. 3 is a schematic diagram showing the main cylinder, concrete pump, and valve.
The figure is a relay circuit diagram, and FIG. 4 is a circuit diagram of a conventional concrete pump sequence drive device. 21... Main hydraulic pump, 26a, 26b... Valve cylinder, 28... Accumulator, 32,
42... Main cylinder, 34, 44... Concrete pump, 36... Valve, 45... 3-position switching valve for main cylinder control, 62... Accumulator selection switch, PS... Pressure switch.

Claims (1)

[Scope of Claims] 1. A main cylinder connected to a hydraulic pump via an oil line to drive the concrete pump, a 3-position switching valve for controlling the main cylinder, and switching between suction and pressure feeding of ready-mixed concrete in the concrete pump. a concrete valve; a valve cylinder that is connected to a hydraulic pump via an oil passage to control the concrete valve and drives the concrete valve; and an accumulator disposed in the oil passage between the hydraulic pump and the valve cylinder. an accumulator selection switch for selecting whether or not to use the accumulator, and an oil pump connected in series with the accumulator operating side contact of the accumulator selection switch and communicating with the accumulator; When the fluid pressure in the oil passage is less than the set pressure of the accumulator, the valve is turned off and the three-position switching valve for controlling the main cylinder is held in the neutral position, allowing pressure oil to accumulate in the accumulator. A concrete pump characterized in that it is equipped with a pressure switch that is turned on when the pressure exceeds a set pressure of the accumulator, switches the main cylinder control switching valve to an operating position, and causes pressure oil to be fed from the accumulator to the valve cylinder. sequence drive device.