JPH06626Y2 - Concrete pump hydraulic switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a hydraulic switching device for a piston type concrete pump.

[Prior Art] (1) In FIG. 4, a high-pressure hydraulic oil obtained from an oil pump 01 is a switching valve incorporated in a hydraulic switching valve block 02.
It is distributed to the main hydraulic cylinder 03 and the gate valve driving hydraulic cylinder 04 through 05 and 06, and the switching valve 05 is the main hydraulic cylinder.
The switching valve 06 controls the flow of the hydraulic oil to the 03, and the switching valve 06 controls the flow of the hydraulic oil to the hydraulic cylinder 04 for driving the gate valve.

Now, when the piston of the main hydraulic cylinder 03 moves toward the arrow in FIG. 4 and reaches the stroke end, the main hydraulic cylinder 03
Switching the switching valve 06 in the opposite direction by the pilot pressure of the gate valve Switching the hydraulic cylinder 04 for driving the gate in the opposite direction
08 is switched in the opposite direction, and the switching valve is set by the pilot pressure at the time of switching.
The switching valve 05 is switched to the opposite side via 07, and the main hydraulic cylinder 03
Is operated in the direction opposite to the arrow in FIG. That is, the fourth
In the case of the figure, the hydraulic cylinders 03 and 04 are alternately switched right and left by the pilot pressure after switching the main hydraulic cylinder 03 and the gate valve driving hydraulic cylinder 04.

(2) In FIG. 5, the high-pressure hydraulic oil obtained from the oil pump 1 is the switching valve incorporated in the hydraulic switching valve block 2.
6 and 7 are distributed to the main hydraulic cylinder 3 and the swing valve driving hydraulic cylinder 4, and the switching valve 6 is the main hydraulic cylinder 3
To the swing valve driving hydraulic cylinder 4, and the switching valve 7 controls the flow of hydraulic oil to the swing valve driving hydraulic cylinder 4.

Now, when the piston of the main hydraulic cylinder 3 operates in the direction of the arrow in FIG. 5 and moves to the stroke end, the switching valve 9 is switched by the electric signal of the piston position detection switch 10, the switching valve 7 is switched in the opposite direction, and the swing The piston of the valve driving hydraulic cylinder 4 is switched to the opposite. When the piston of the swing valve driving hydraulic cylinder 4 moves to the stroke end, the switching valve 8 is switched by the electric signal of the piston position detection switch 11 and the switching valve 6 is switched to the opposite direction, and the piston of the main hydraulic cylinder 3 is moved in the direction opposite to the arrow. Works. That is, in the case of FIG. 5, the main hydraulic cylinder 3 and the swing valve driving hydraulic cylinder 4 are alternately switched to the left and right by an electric signal obtained by detecting the piston position of the hydraulic cylinder.

[Problems to be solved by the invention]

The conventional hydraulic circuits shown in FIGS. 4 and 5 have the following problems.

(1) In the case of the device shown in FIG. 4, the gate valve for switching the switching valve 06 for switching the main hydraulic cylinder 03 with the driving pressure for switching the gate valve driving hydraulic cylinder 04 as the pilot pressure.
If 08 requires a large switching force, switching valve 06 will switch quickly because a large pilot pressure is generated even though gate valve 08 is in the process of switching, so the main hydraulic pressure in the next step Cylinder 03 starts to operate, gate valve 08 remains in a half-opened state, and concrete is not pumped smoothly. Further, if the operation is stopped during the switching process of the gate valve, the gate valve will stop in a half-open state, and if there is a rising portion in the concrete pipe, the head pressure will cause the concrete to flow back. Besides, the control by the hydraulic pilot pressure is apt to malfunction due to the influence of the oil temperature change of the working oil, the oil pressure, the internal leak of the switching valve, the contamination and the like. Therefore, it is necessary to adjust the throttle valve according to the operating conditions, but skill is required to achieve the optimum state.

(2) In the case of the device shown in FIG. 5, since the piston position of the swing valve driving hydraulic cylinder 4 is detected and the main hydraulic cylinder 3 is switched by the electric signal of the switch 11, the swing valve
When 16 does not completely switch due to the inclusion of aggregates, etc., the concrete pump stops in this state and it is necessary to take measures to stop the pump once and switch the swing valve 16 completely without moving to the next process. .

Further, since the piston position is detected, the switching force is always the maximum pressing force due to the pressure set by the safety valve 5, and the maximum surge pressure is always generated regardless of the concrete pumping load, which affects the temperature rise of the hydraulic oil. Since switching is always performed with the maximum switching force, it causes vibration and noise due to impact noise during switching.

In addition, in the position detection control, it is necessary to detect an externally moving object, which complicates the structure and has some safety problems.

[Means for solving problems]

When the switching of the intake / discharge switching valve is completed, the hydraulic pressure for driving the intake / discharge valve rises, and the rise in pressure is detected by the pressure switch and used as the switching signal for the main hydraulic cylinder circuit.

When the circuit internal pressure is set and rises to the pressure, the process proceeds to the next step, and the switching force is optimally controlled by setting the pressure according to the load in the circuit.

[Action]

(B) When the intake / discharge valve switching is completed and the circuit pressure rises to an arbitrary pressure set pressure, the pressure switch operates and an electric signal is output to switch the main hydraulic cylinder.

(B) By properly selecting the set pressure of the pressure switch, the valve switching force can be freely controlled.

(C) Since the switching valve is switched by the electric signal from the pressure switch, even if the operation is stopped during the switching, the valve can be stopped after the switching completely.

〔Example〕

FIG. 1 shows a hydraulic circuit diagram of the embodiment. The high-pressure hydraulic oil obtained by the oil pump 1 passes through the switching valves 6 and 7 incorporated in the hydraulic switching valve block 2, is distributed to the main hydraulic cylinder 3 and the swing valve driving hydraulic cylinder 4, and is switched to the switching valve 6.
Controls the flow of hydraulic oil to the main hydraulic cylinder 3, and the switching valve 7 controls the flow of hydraulic oil to the swing valve driving hydraulic cylinder 4. Now, when the piston of the main hydraulic cylinder 3 operates in the direction of the arrow in FIG. 1 and moves to the stroke end, the switching valve 9 is switched by the electric signal of the piston position detection switch 10 or 11, and the switching valve 7 is switched in the opposite direction. ,
The piston of the swing valve driving hydraulic cylinder 4 is switched in the opposite direction. Swing valve drive hydraulic cylinder 4
When the circuit pressure rises to the pressure set value of the pressure switch 21 or 22 after the completion of the piston switching, the switching valve 8 is switched by the electric signal of the pressure switch 21 or 22 and the switching valve 6 is switched in the opposite direction, and the piston of the main hydraulic cylinder 3 The opposite can be switched.

Here, as a condition for sending a signal to the solenoid valve 13 of the main hydraulic cylinder switching switching valve 8, as shown in FIG. 2, an electric signal to the solenoid valve 14 of the swing valve driving hydraulic cylinder switching switching valve 9 is used. , When both of the electric signals of the pressure switch 21 are turned on, the condition for sending a signal to the solenoid valve 12 is that the solenoid valve of the switching valve 9
When both the electric signal to 15 and the electric signal of the pressure switch 22 are turned on, the swing valve 16 is received by receiving the electric signal for switching the swing valve (the electric signal to the solenoid valve 14 or 15). After the operation is completed, increase the pressure in the hydraulic circuit of the swing valve driving hydraulic cylinder 4 by changing the pressure.
The sequence is detected by 21 or 22, and the main hydraulic cylinder 3 is operated in the direction of the arrow in FIG. 1 or in the direction opposite to the arrow.

Use a pressure switch 21 or 22 with a structure that can set the pressure arbitrarily. Mixing ratio of concrete and pipe condition (it is necessary to increase the switching force when poorly mixed concrete or high-pressure pumping, conversely when the pumping load is small. It is possible to freely change the pressure switch set pressure by lowering the switching force to increase the temperature of hydraulic oil, noise and vibration.

In the electric circuit shown in Fig. 3, when the concrete pump operation switch SW is turned on and the operation is started, the input signal (A) of the holding circuit becomes high and the output signal (B) becomes high and the signal during operation is changed. The output signal of (B) is output here.
When the output signal (B) returned to the input side of the R circuit becomes high once, the input signal (C) of the OR circuit also becomes high, turning off the concrete pump operation switch SW, and input vibration (C) even when the operation is stopped. Solenoid valve unless is low
The input signal for switching 14 or 15 is continuously output, and switching of 14 or 15 is continued until the swing valve 16 is completely switched. When the swing valve 16 is completely switched, the swing valve switching completion signal (D) becomes high, the input signal (C) of the OR circuit becomes low, and the swing valve 16 is completely switched even if the concrete pump operation switch SW is stopped. Can be stopped.

In the above-mentioned embodiment, the swing valve 16 is used as the concrete intake / discharge switching valve, but the swing valve is not limited to the swing valve type, and any other type such as the gate valve type (plate valve) shown in FIG. Any valve type may be used.

[Effect of device]

(1) It becomes possible to freely control the switching force of the gate valve. Therefore, it is possible to save energy without wasting energy.

(2) The control such as half-opening prevention of the gate valve can be advanced.

(3) It is safe and simple because there is nothing that operates externally.

(4) Continuous operation is possible without stopping even if the aggregate gets caught in the gate valve.

(5) Pressure switch The set pressure can be freely controlled, and the valve switching force can be freely selected.

(6) It is possible to operate with the optimum energy (switching force) without wasting energy, and at the same time it is possible to prevent the rise of oil temperature and the impact noise generated during switching.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of an embodiment of a concrete pump hydraulic switching device of the present invention, FIG. 2 is an electrical system block diagram of the device of FIG. 1, and FIG. 3 is an electrical system block diagram of a holding circuit of the device of FIG. is there. 4 and 5 are hydraulic circuit diagrams of a conventional device, respectively. 1 ... Oil pump 2 ... Hydraulic switching valve block 3 ... Main hydraulic cylinder 4 ... Concrete suction / discharge switching valve drive hydraulic cylinder 10,11 ... Piston position detection switch 16 ... Concrete suction / discharge switching valve 21,22 ... Pressure switch

Claims (1)

[Scope of utility model registration request] 1. A piston having a pair of main hydraulic cylinders for driving a concrete pump, a hydraulic cylinder for driving a concrete suction / discharge switching valve, and a plurality of switching valves for switching pressure oil supplied to the hydraulic cylinders. In a hydraulic concrete pump, a pressure that is provided in a hydraulic circuit and that outputs a switching signal to the switching valve of the main hydraulic cylinder when the switching pressure of the switching valve is set and the circuit pressure of the drive hydraulic cylinder reaches the set pressure. Concrete pump hydraulic switching device characterized by having a switch.