JPH0557367U - Viscous fluid pump control circuit - Google Patents

Abstract

(57) [Summary] [Purpose] Effective use of the hydraulic pump by operating the main hydraulic cylinder and valve operation with one hydraulic pump,
Allows smooth valve switching. [Structure] A main circuit I for alternately reciprocating two main hydraulic cylinders 7, 8 and two swing cylinders 1
A valve circuit II for alternately operating 6 and 17 is provided. The main circuit I and the valve circuit II are connected to the discharge side of the hydraulic pump 30 via one electromagnetic switching valve 29. The hydraulic pump 30 is of a variable displacement type so that the tilt can be changed. The tilt change is
It is performed by the control oil pump 32, the electromagnetic switching valve 36, the tilt change switching valve 34, and the actuator 33.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a control circuit for a viscous fluid pump that sucks and discharges viscous fluid such as concrete.

[0002]

[Prior Art]

 For viscous fluid pumps in which viscous fluid such as concrete in the hopper is alternately sucked and discharged by two fluid pressure feeding cylinders, a slide valve type is used as a suction and discharge valve for switching suction and discharge, It is conventionally known that an oscillating valve type is adopted.

As shown in FIGS. 2 and 3, a conventional viscous fluid pump having a swing valve type suction and discharge valve is provided with two suction and discharge ports 2 arranged side by side on the lower front surface of the hopper 1, and Outside, two fluid pressure feeding cylinders 3 and 4 respectively communicating with the two suction and discharge ports 2 are installed in parallel, and fluid pressure feeding pistons 5 housed in the respective fluid pressure feeding cylinders 3 and 4 are installed. Is integrally connected to the main hydraulic pistons 9 in the main hydraulic cylinders 7 and 8 connected to the fluid pressure-feeding cylinders 3 and 4 through the cleaning chamber 6 through the rods 10 respectively. By alternately moving the cylinders 7 and 8 forward and backward, the fluid pressure feeding piston 5 is moved forward and backward alternately. Further, an oscillating tube 11 bent in an S shape is located in the hopper 1, and a seal ring 12 is attached to one end of the oscillating tube 11 so that the two intake and discharge ports 2 can be alternately aligned. In addition, the other end of the rocking pipe 11 is connected to the transport pipe 13 by penetrating the back surface of the hopper 1, and the connecting shaft 14 fixed in the middle of the rocking pipe 11 is placed outside the hopper 1. By connecting the two installed rocking cylinders 16 and 17 via the operating lever 15 and tilting the operating lever 15 to the left and right, the rocking tube 11 can be rocked in the lateral direction about the connecting shaft 14. Is done.

When the viscous fluid 18 in the hopper 1 is sucked and discharged by the viscous fluid pump described above, the suction / discharge port corresponding to the fluid pressure feeding cylinder 3 that has already sucked by swinging the swing pipe 11 When it is positioned at 2, the fluid pressure feeding piston 5 of the fluid pressure feeding cylinder 3 is advanced by the main hydraulic cylinder 7 and the viscous fluid sucked into the fluid pressure feeding cylinder 3 is discharged through the oscillating pipe 11 at the same time. , Another fluid pressure-feeding cylinder 4 retracts the fluid pressure-feeding piston 5 so that the viscous fluid 18 in the hopper 1 is sucked through the suction / discharge port 2, and then the rocking pipe 11 is sucked in differently from the above. The fluid pressure feeding cylinders 3 and 4 are swung to the discharge port 2 side to operate in the opposite manner to the above, so that the viscous fluid is continuously discharged through the swing pipe 11.

An example of the control circuit of the viscous fluid pump that suctions and discharges the viscous fluid as described above is shown in FIG. 4. As shown in FIG. 4, the head-side pressure chambers of the two main hydraulic cylinders 7 and 8 are provided. An electromagnetic four-way valve 20 is provided in the middle of a pressure oil supply / discharge line 19 for supplying / discharging pressure oil to / from the rod-side pressure chambers of the main hydraulic cylinders 7 and 8 by a sealing circuit 22. The pressure oil discharged from the hydraulic pump 21 is alternately supplied to the main hydraulic cylinder 7 or 8 by this switching, and the main hydraulic cylinders 7 and 8 are alternately moved forward and backward to alternate the fluid pressure feeding cylinders 3 and 4. Is switched to the suction side and the discharge side so that the viscous fluid is discharged into the transport pipe 13, and the electromagnetic four-way valve is provided in the middle of the line 23 for supplying and discharging the pressure oil to the two rocking cylinders 16 and 17. 24 is provided and the electromagnetic four-way valve 24 is turned off. By exchanging, the rocking cylinders 16 and 17 are alternately moved forward and backward to allow the rocking tube 11 to rock to the left and right. Sensors LS1 and LS2 are provided at the forward stroke ends of the main hydraulic cylinders 7 and 8, and sensors LS3 and LS4 are provided at the stroke ends of the oscillating cylinders 16 and 17 to provide the oscillating cylinder. When the oscillating cylinder 11 or 17 reaches the stroke end and the sensor LS3 or LS4 is actuated by switching the oscillating pipe 11 with the solenoid SOL. 2 or SOL. 1 is excited so that the electromagnetic four-way valve 20 is switched to the port b or a, and when the main hydraulic cylinder 7 or 8 reaches the stroke end and the sensor LS1 or LS2 operates, the electromagnetic four-way valve 24 Solenoid SOL. 4 or SOL. 3 is excited so that the electromagnetic four-way valve 24 can be switched to the port b or a, and the solenoid SOL. 1 or SOL. 2, pressure oil from an accumulator Acc provided in the pressure oil supply line to the rocking cylinders 16 and 17 is constantly operated via a line 25. For example, a solenoid SOL. 1 is excited and the electromagnetic four-way valve 20 is switched to the port a, the solenoid SOL. The pressure oil is allowed to escape from the No. 2 side to the tank 27 through the line 26. 28 is a relief valve.

[0006]

[Problems to be solved by the device]

However, in the above-mentioned conventional control circuit, the main circuit for driving the main hydraulic cylinders 7 and 8 and the valve circuit for driving the oscillating cylinders 16 and 17 have different hydraulic sources, and the oscillating cylinders 16 and 17 are provided. There is a problem that the hydraulic pump 21 of the main circuit is idle when it is driven, and it is not effectively utilized. Moreover, the conventional control circuit uses the accumulator Acc. The output of the accumulator Acc depends on the pressure of the N ₂ gas charged on the gas side. When the pressure changes due to the volume change of the gas side, the output changes and the output drops due to the decrease in gas pressure.

Therefore, the present invention makes it possible to drive the main circuit and the valve circuit with a single hydraulic pump to effectively utilize the hydraulic pump, eliminates the need for a valve circuit drive device, and further, when using an accumulator. It is intended to eliminate such a problem of pressure drop.

[0008]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention has a common main circuit for supplying and discharging pressure oil to two main hydraulic cylinders and a valve circuit for supplying and discharging pressure oil to two swing cylinders. It is connected to the discharge side of the variable hydraulic pump and the tank via an electromagnetic switching valve, and an electromagnetic four-way valve is provided separately in the main circuit and valve circuit, and the tilt angle of the variable hydraulic pump is changed. Therefore, a control oil pump for adjusting the discharge amount of the hydraulic pump and a tilt conversion switching valve for operating the actuator by the discharge pressure of the control oil pump are provided.

[0009]

[Action]

 When the common electromagnetic switching valve is switched to the main circuit and the valve circuit, the discharge hydraulic pressure from the variable hydraulic pump is distributed to the main circuit and the valve circuit to act on them, and they are incorporated in the main circuit and the valve circuit, respectively. By switching the electromagnetic four-way valve, either one of the two main hydraulic cylinders can be moved forward, or one of the two rocking cylinders can be extended to switch the valve. The hydraulic pump is used effectively because it is used to drive the main circuit and valve circuit. When the tilt of the variable hydraulic pump is changed by the pressure oil from the control oil pump, the discharge amount of the variable hydraulic pump can be increased or decreased.

[0010]

【Example】

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

FIG. 1 shows an embodiment of the present invention. Similar to the control circuit of the conventional viscous fluid pump shown in FIG. 4, pressure oil is supplied to the head side pressure chambers of the two main hydraulic cylinders 7 and 8. An electromagnetic four-way valve 24 is provided in the middle of a pressure oil supply / discharge line 23 for supplying / discharging oil, and a main circuit is formed by connecting two rod-side pressure chambers of two main hydraulic cylinders 7 and 8 with a sealed circuit 22. A circuit I and a valve circuit II including an electromagnetic four-way valve 24 are provided in the middle of a pressure oil supply / discharge line 23 for supplying / discharging pressure oil to / from the two rocking cylinders 16 and 17, and the main hydraulic pressure When one of the sensors LS1 and LS2 provided at the forward stroke end of the cylinders 7 and 8 is activated, the solenoid SOL. 3 and SOL. One of the sensors LS3 and LS4 installed at the stroke end of the rocking cylinders 16 and 17 is adapted to switch the electromagnetic four-way valve 24 to the port a or b. When one of them operates, the solenoid SOL. 1 and SOL. In a configuration in which either one of the two is excited to switch the electromagnetic four-way valve 20 to the port a or b, the main circuit I and the valve circuit II are connected via a common electromagnetic switching valve 29. Connect the discharge side of the variable hydraulic pump 30 to the tank 31 so that the pressure oil from the variable hydraulic pump 30 is distributed to the main circuit I or the valve circuit II by switching the electromagnetic switching valve 29. .. Further, a control oil pump 32 is provided in parallel with the variable hydraulic pump 30, and a tilt change switching valve 34 for operating an actuator 33 for changing the tilt angle of the variable hydraulic pump 30 is provided. The pressure oil from the control oil pump 32 is decompressed by the pressure reducing valve 35 so as to be used as a hydraulic pressure source for switching the tilt change changeover valve 34, and further the pressure reduction on the discharge side of the control oil pump 32 is performed. It is possible to connect the inlet side of the valve 35 and the tilt change changeover valve 34 via an electromagnetic changeover valve 36, and to switch the tilt changeover changeover valve 34 at high pressure by switching the electromagnetic changeover valve 36. It can be so . Solenoid SOL. 5 is excited by, for example, a detection signal of the discharge amount of the viscous fluid so that the pressure oil from the control oil pump 32 does not pass through the pressure reducing valve 35 and directly acts on the tilt change switching valve 34. , The solenoid SOL. 6 is excited when the sensors LS3 and LS4 at the stroke ends of the rocking cylinders 16 and 17 are activated, and the solenoids SOL. 7 is excited when the sensors LS1 and LS2 at the forward stroke ends of the main hydraulic cylinders 7 and 8 are activated. 37 and 38 are relief valves.

Now, the electromagnetic four-way valve 24 of the valve circuit II is switched to the port b side as shown in the figure, and the swing pipe 11 shown in FIG. 2 is swung to the main hydraulic cylinder 8 side. When the main hydraulic cylinder 8 reaches the stroke end and the sensor LS2 operates when the viscous fluid is being pressure-fed through the oscillating pipe 11 due to the extension operation of the cylinder 8, the solenoid SOL of the electromagnetic four-way valve 24 of the valve circuit II is activated. ． 3 is excited and switched to the port a, and at the same time, the solenoid SOL. 7 is excited and switched to port b. As a result, the pressure oil from the variable hydraulic pump 30 as the main pump is supplied to the valve circuit II side and is supplied to the rocking cylinder 16 through the port a of the electromagnetic four-way valve 24. (See FIG. 2) is swung to the main hydraulic cylinder 7 side. When the sensor LS3 is activated by the extension operation of the oscillating cylinder 16, the solenoid SOL. 2 is excited and switched to port b, and at the same time, the solenoid SOL. 6 will be excited and switched to port a. As a result, the pressure oil from the hydraulic pump 30 is supplied to the main circuit I side to advance the main hydraulic cylinder 7, and the viscous fluid is pressure-fed.

When the main hydraulic cylinder 7 reaches the stroke end and the sensor LS1 operates, the solenoid SOL. 4 is excited, and at the same time, the solenoid SOL. 7, the pressure oil from the variable hydraulic pump 30 is switched to the valve circuit II side, the swing cylinder 17 is extended, and the swing pipe is switched to the main hydraulic cylinder 8 side. When the sensor LS4 is activated by the extension operation of the oscillating cylinder 17, the solenoid SOL. 1 is excited, and at the same time the solenoid SOL. 6 will be excited.

As described above, the electromagnetic switching valve 29 can supply the pressure oil in the two directions of the main circuit I and the valve circuit II, so that the hydraulic pump 30 can be effectively utilized without idling.

Next, for example, when the discharge amount of the viscous fluid is small, the solenoid SOL. 5, the discharge oil of the control oil pump 32 is caused to act on the tilt change switching valve 34 without passing through the pressure reducing valve 35, and the actuator 33 is operated to change the tilt angle of the hydraulic pump 30. To As a result, it becomes possible to increase the discharge amount of the hydraulic pump 30 and switch the rocking pipes at high speed.

Although the oscillating valve type is illustrated as the intake / discharge valve, other types may be used.

[0017]

[Effect of the device]

 As described above, according to the control circuit of the viscous fluid pump of the present invention, the two main hydraulic cylinders for alternately sucking and discharging the viscous fluid by alternately reciprocating the two fluid pressure cylinders are alternately used. A main circuit for reciprocating the valve and a valve circuit for alternately switching the intake and discharge valves according to the switching of the main circuit are connected to the discharge side of the variable hydraulic pump via the electromagnetic switching valve. Since it is connected and the tilt of the variable hydraulic pump can be changed by the discharge hydraulic pressure from the control oil pump, it is possible to operate both the main circuit and the valve circuit with one hydraulic pump, The output of the hydraulic pump can be effectively utilized, the drive device for valve operation can be eliminated, and shock absorption can be easily achieved. Further, the output can be supplied to the valve circuit. Oil pressure is constant From, rather than such a pressure drop upon conventional accumulator used, thereby the valve driving force is not changed, smooth valve switching is possible, the effect is also obtained, et al is called.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a control circuit of a viscous fluid pump of the present invention.

FIG. 2 is a partially cut side view showing an example of a viscous fluid pump.

FIG. 3 is a view showing a portion for rocking a rocking tube of the viscous fluid pump of FIG.

FIG. 4 is a control circuit diagram of a conventional viscous fluid pump.

[Explanation of symbols]

 I Main circuit II Valve circuit 1 Hopper 3,4 Fluid pressure feeding cylinder 7,8 Main hydraulic cylinder 11 Swing pipe 16,17 Swing cylinder 20,24 Electromagnetic four-way valve 29 Electromagnetic switching valve 30 Variable hydraulic pump 31 Tank 32 Control Oil Pump (Tilt Change Device) 33 Actuator (Tilt Change Device) 34 Tilt Change Switching Valve (Tilt Change Device) 36 Electromagnetic Change Valve (Tilt Change Device)

Claims (1)

[Scope of utility model registration request] 1. A main circuit for supplying and discharging pressure oil to and from two main hydraulic cylinders for sucking and discharging a viscous fluid by alternately reciprocating two fluid pressure feeding cylinders, and switching between the main circuits. A valve circuit for alternately switching the intake and discharge valves is connected to the discharge side of the variable hydraulic pump and the tank via one electromagnetic switching valve, and the main circuit and the valve circuit are separately electromagnetically connected. A control circuit for a viscous fluid pump, further comprising a variable four-way valve, and a tilt changing device for changing the tilt angle of the variable hydraulic pump to adjust the discharge amount of the hydraulic pump. ..