JPH0634703U - Bubble removal device in hydraulic circuit of construction machine - Google Patents

Abstract

(57) [Summary] [Purpose] Air that can be automatically removed during operation without stopping the operation of the machine and without performing manual air bleeding work. [Structure] An air bleed filter 4 is provided in the middle of a suction circuit 3 extending from a hydraulic oil tank 1 to a hydraulic pump 2 to discharge air from the oil in the circuit 3 to the outside. [Effect] The air in the circuit can be removed directly to the outside of the circuit while the machine is running, eliminating the air bleeding work that was necessary in the past, and preventing damage due to cavitation of hydraulic equipment. The life of the equipment can be greatly improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hydraulic circuit used in a construction machine, and more particularly to a device for removing bubbles in the hydraulic circuit.

[0002]

[Prior art]

 Conventionally, a large amount of air bubbles are mixed in the circuit immediately after assembly or maintenance such as connection between hydraulic equipment and piping, so that the amount of bubbles in the circuit should be below the standard value at the beginning of operation. Bleeding is performed.

[0003]

[Problems to be Solved by the Invention] If such air bleeding is neglected, the hydraulic pump and the hydraulic cylinder may be damaged. I had to suspend the operation.

In view of the above, the present invention has made it possible to automatically remove air during operation without stopping the operation of the machine, and without manually removing the air, thereby removing bubbles in a hydraulic circuit of a construction machine. The purpose is to provide a device and solve the drawbacks of the conventional technology.

[0005]

[Means for Solving the Problems] As a means for solving the above-mentioned problems of the prior art, claim 1 of the present invention provides an air vent filter in the middle of a suction circuit from a hydraulic oil tank to a hydraulic pump. Is characterized in that air is discharged to the outside from the above oil, and in claim 2, the oil in the hydraulic oil tank is sucked and discharged by a gear pump separately from the circuit for discharging the oil, and An air bleeding filter is connected to the discharge side of the gear pump to provide a circulation circuit for releasing the air on the discharge side to the outside and returning only the oil to the tank. An air bleeding filter is provided in the middle of the suction circuit leading to the pump so that air from the oil in the circuit is always returned directly into the tank. The air vent filter is installed in the middle of the suction circuit from the engine to the hydraulic pump, and a solenoid valve is installed in the middle of the pipe line that connects the air outlet of the air vent filter and a separately provided oil reservoir. The switch in the driver's cab turns it on and off, and the monitor in the driver's cab also detects the tank fullness of the oil that has flowed out with the air released to the atmosphere. According to claim 5, an air vent filter is provided in the middle of the suction circuit from the hydraulic oil tank to the hydraulic pump, and an electromagnetic valve is provided in the middle of the pipeline connecting the air outlet of the air vent filter and a separately provided oil sump container. A valve and a float sensor for detecting bubbles containing air are provided, and the controller turns the solenoid valve on and off according to a detection signal from the float sensor. Banamo - the rotation of the motor controller - characterized by Le.

[0006]

[Action]

 According to the above configuration, in the hydraulic circuit of the construction machine, the air in the circuit can be discharged to the outside of the circuit while operating the machine.

[0007]

【Example】

 1 is an embodiment of a bubble removing device for a hydraulic circuit of a construction machine according to claim 1 of the present invention, FIG. 2 is an embodiment of a bubble removing device according to claim 2 of the present invention, and FIG. 4 is an embodiment of the bubble removing apparatus according to claim 4, FIG. 5 is an embodiment of the bubble removing apparatus according to claim 5, and FIG. 6 is a flow chart of FIG. -It is a chart.

The present invention will be described below with reference to the embodiments shown in FIGS. 1 to 6, but a known air bleeding filter is used. Further, the same reference numerals are used for all common parts in FIGS. 1 to 5. According to claim 1 of the present invention, as shown in FIG. 1, an air bleed filter 4 is provided in the middle of the suction circuit 3 from the hydraulic oil tank 1 to the hydraulic pump 2 to discharge air from the oil in the circuit 3 to the outside. It was done like this.

Since the hydraulic pump 2 sucks the oil from the hydraulic oil tank 1, the oil reaching the pump 2 is at atmospheric pressure or less, and the air is easily separated. The dotted line 5 in the figure shows the direction of air release.

According to a second aspect of the present invention, as shown in FIG. 2, the oil in the hydraulic oil tank 1 is sucked and discharged by the hydraulic pump 2, and the oil in the tank 1 is separated from the circuit 3 by a gear pump 6 A circulation circuit 7 is provided for connecting the air suction filter 4 to the discharge side of the gear pump 6 and connecting the air bleeding filter 4 to discharge the air on the discharge side to the outside and returning only the oil to the tank 1.

As a result, bubbles of the oil in the hydraulic oil tank 1 are constantly discharged to the outside of the tank 1, and the bubbles are removed, so that air does not enter the suction side of the hydraulic pump 2.

As a means for removing bubbles, the oil in the hydraulic oil tank is sucked by a hydraulic pump, discharged and supplied to a control valve, and used oil is returned from the control valve to the tank. In the circuit, an air bleeding filter may be provided in the return circuit from the control valve to the tank to discharge the air in the oil to the outside.

Claims 3 to 5 of the present invention specifically show the release of air. In claim 3, the suction from the hydraulic oil tank 1 to the hydraulic pump 2 is shown in FIG. The air bleeding filter 4 is provided in the middle of the circuit 3 so that the air from the oil in the circuit 3 is always returned directly into the tank 1.

That is, a pipe 8 for allowing only bubbles to pass from the air bleeding filter 4 into the tank 1 is connected to a height near the oil level of the tank 1 so that the air is discharged from the oil surface. Is directly returned to the tank 1 before entering the hydraulic pump 2. In this case, it is conceivable that a cock that can be opened and closed is provided in the middle of the pipe line 8 and when air enters the circuit for maintenance or repair, the air may be bleed to be released to the atmosphere by manual operation after starting. As described in claim 4, it is more efficient.

According to a fourth aspect of the present invention, as shown in FIG. 4, an air bleed filter 4 is provided in the middle of the suction circuit 3 from the hydraulic oil tank 1 to the hydraulic pump 2, and an air discharge port 4a of the air bleed filter 4 is provided. A solenoid valve 10 is provided in the middle of a pipe line 8 connecting to a separately provided oil sump container 9, and the solenoid valve 10 is turned on and off by a switch 12 provided in a driver's cab 11 and also provided in the driver's cab 11. The monitor 13 detects the fullness of the oil in the container 9 flowing out together with the air released to the atmosphere.

According to this, when the operator wants to bleed air, by turning on the switch 12, the solenoid valve 10 which has been closed until now is opened, and air bubbles from the air bleeding filter 4 are removed. Inside, air escapes to the atmosphere, and only oil accumulates in the container 9. When the monitor 13 provided in the operator's cab 11 detects that the storage amount is full, the switch 12 is turned off and the solenoid valve 10 is closed.

According to a fifth aspect of the present invention, as shown in FIG. 5, an air bleed filter 4 is provided in the middle of the suction circuit 3 from the hydraulic oil tank 1 to the hydraulic pump 2, and an air discharge port 4a of the air bleed filter 4 is provided. A solenoid valve 10 and a float sensor 14 for detecting air bubbles including air are provided in the middle of a pipe line 8 connecting to a separately provided oil sump container 9, and a controller outputs a detection signal from the float sensor 14. 15 turns the solenoid valve 10 ON and OFF, and if the air is above the specified level, the rotation of the governor motor 16 is reduced so that the engine speed is reduced to prevent pump damage and the speed is restored after the air is removed. Is controlled.

That is, a small oil reservoir 17 to which the float sensor 14 is attached is provided in front of the solenoid valve 10 in the pipe line 8 connecting the air discharge port 4a and the separately provided oil reservoir container 9, When air bubbles are accumulated in the small oil sump 17 at a certain height, the float sensor 14 detects this and causes the controller 15 to turn on the solenoid valve 10 and at the same time, the governor motor 16 of the engine. A signal is sent to control the rotation, and the air is automatically released to the atmosphere. In the present invention, a photothyristor or the like may be used instead of the float sensor 14.

Next, the automatic opening to the atmosphere according to claim 5 will be described with reference to the flowchart shown in FIG. First, a start is performed to automatically release the air to the atmosphere. If air is present in the suction pipe 3 in step 1, the air is accumulated in the small oil sump 17, and if the float sensor 14 detects this, a signal is sent to the controller 15. If the controller 15 is a signal from the float sensor 14 and "Are there air?" Is yes, the solenoid valve 10 is turned on to open the air to the oil reservoir 9 and "If the engine speed is idling? If no, the governor signal is used for low idling. In step 2, it is judged whether or not the preset time required for bleeding air has been reached. If the answer is yes, the solenoid valve 10 is turned off, and the rotation of the governor motor 16 is proportional to the throttle lever. To control. When Step 1 and Step 2 are no, the original flow is returned to and the flow from Step 1 to Step 2 is repeated.

[0020]

[Effect of device]

 As described above, according to the present invention, in claim 1, an air bleeding filter is provided in the middle of the suction circuit from the hydraulic oil tank to the hydraulic pump, and air is discharged from the oil in the circuit to the outside. Separately from the circuit for sucking and discharging the oil in the hydraulic oil tank with a hydraulic pump, the oil in the tank is sucked with a gear pump, and an air bleed filter is connected to the discharge side of the gear pump to externally discharge the air on the discharge side. A circulation circuit for returning only oil to the tank is provided. In claim 3, an air bleed filter is provided in the middle of the suction circuit from the hydraulic oil tank to the hydraulic pump, and air from the oil in the circuit is introduced into the tank. It is always returned directly, and in claim 4, an air bleeding filter is provided in the middle of the suction circuit from the hydraulic oil tank to the hydraulic pump, and the air bleeding filter is installed. A solenoid valve is provided in the middle of the pipeline that connects the discharge port and a separately provided oil sump container, and the solenoid valve is turned on and off by a switch provided in the operator's cab, and a monitor also provided in the operator's cab The fullness of the oil outflowing with the air released to the atmosphere is detected in the container. In claim 5, an air bleeding filter is provided in the suction circuit from the hydraulic oil tank to the hydraulic pump, and the air bleeding is performed. An electromagnetic valve and a float sensor for detecting air bubbles containing air are installed in the middle of the conduit connecting the air outlet of the filter and a separately provided oil reservoir, and the detection signal from the float sensor is used. Since the controller turns the solenoid valve on and off and controls the rotation of the governor motor, the air in the circuit is removed directly from the circuit while the machine is running. Will be cut, an air vent work that has been done to stop the a mechanical conventionally required is unnecessary, hydraulic equipment of cavitation - damage prevention by Deployment is achieved, hydraulic equipment of life can be greatly improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a bubble removing device in a hydraulic circuit of a construction machine according to claim 1 of the present invention.

FIG. 2 is an explanatory view showing an embodiment of a bubble removing device according to claim 2 of the present invention.

FIG. 3 is an explanatory view showing an embodiment of a bubble removing device according to claim 3 of the present invention.

FIG. 4 is an explanatory view showing an embodiment of a bubble removing device according to claim 4 of the present invention.

FIG. 5 is an explanatory view showing an embodiment of a bubble removing device according to claim 5 of the present invention.

FIG. 6 is an explanatory view showing the flow chart of FIG.

[Explanation of symbols]

 1 Hydraulic Oil Tank 2 Hydraulic Pump 3 Suction Circuit 4 Air Venting Filter 4a Air Discharge Port 6 Gear Pump 7 Circulation Circuit 8 Pipeline 9 Oil Reservoir Container 10 Solenoid Valve 11 Operator's Room 12 Switch 13 Monitor 14 Float Sensor 15 Controller 16 Governor -

Claims (5)

[Scope of utility model registration request] 1. A bubble removing device in a hydraulic circuit of a construction machine, wherein an air bleeding filter is provided in the middle of a suction circuit from a hydraulic oil tank to a hydraulic pump, and air is discharged from the oil in the circuit to the outside. . 2. A circuit for sucking and discharging oil in a hydraulic oil tank by a hydraulic pump, the oil in the tank is sucked in by a gear pump, and an air bleeding filter is connected to the discharge side of the gear pump to discharge the oil. A bubble removal device in a hydraulic circuit of a construction machine, which is provided with a circulation circuit that discharges air from the outside to return only oil to the tank. 3. A hydraulic system for a construction machine, wherein an air bleeding filter is provided in the middle of a suction circuit from a hydraulic oil tank to a hydraulic pump, and air from the oil in the circuit is constantly returned directly into the tank. Air bubble removal device in the circuit. 4. An air bleed filter is provided in the middle of the suction circuit from the hydraulic oil tank to the hydraulic pump, and a solenoid valve is provided in the pipeline connecting the air discharge port of the air bleed filter and a separately provided oil sump container. A solenoid valve is provided to turn on / off the solenoid valve by a switch provided in the driver's cab, and a monitor also provided in the operator's cab detects the fullness of the oil outflowing with the air and the container. A bubble removing device in a hydraulic circuit of a construction machine characterized by the above. 5. An electromagnetic valve is provided in the middle of a suction circuit from a hydraulic oil tank to a hydraulic pump, and a solenoid valve is provided in a pipeline connecting an air discharge port of the air bleed filter and an oil reservoir provided separately. And a float sensor for detecting air bubbles including air, and the controller turns on and off the solenoid valve according to the detection signal of the float sensor and controls the rotation of the governor motor. The air bubble removal device in the hydraulic circuit of the characteristic construction machine.