JP2001200803A - Hydraulic circuit of industrial machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic circuit of industrial machinery capable of supplying pressurized oil of standard flow rate in standard condition and, as required, assuring the pressurized oil of a flow rate larger than the standard flow rate in standard condition. SOLUTION: This hydraulic circuit of an industrial vehicle having a hydraulically operated attachment 9 comprises a standard pump 2 supplying pressurized oil of standard flow rate, a flow increasing pump 1 allowing to supply the pressurized oil of a flow rate equal to a difference between the standard flow rate and a specified maximum flow rate, and a merging selector valve 3, as necessary, allowing the discharge pipeline 22 of the flow increasing pump 1 to communicate with the discharge pipeline 20 of the standard pump 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit of an industrial machine having a hydraulically operated working device, which can secure a larger flow rate of hydraulic oil than a standard state as required in an industrial machine. .

[0002]

2. Description of the Related Art An industrial machine having a hydraulically-operated working device is provided with a standard operating device, for example, a working vehicle in which various attachments are exchanged and used. In some cases, a larger amount of pressure oil is required than the flow rate in the state.

Conventionally, such an industrial machine has been equipped with a hydraulic pump having a capacity of one to two grades larger than that of an optimum capacity in a standard state in order to cope with a necessary large flow rate. However, when a hydraulic pump with such a large capacity is installed, a large flow rate of hydraulic oil is constantly supplied from the hydraulic pump, so that when a standard working device is used, the working speed of the working device increases. May cause an accident.

Therefore, there is a hydraulic circuit in which a restrictor is provided in the hydraulic circuit, but the restrictor may not be able to exhibit the original performance of the machine, and the energy efficiency is also deteriorated.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problem in an industrial machine having a hydraulically operated working device. It is an object of the present invention to provide a hydraulic circuit of an industrial machine capable of securing a larger amount of hydraulic oil than a standard state.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a standard pump for supplying a standard flow rate of hydraulic oil to a hydraulic circuit of an industrial machine equipped with a hydraulically operated working device; A flow increasing pump capable of supplying a pressure oil having a flow rate different from a required large flow rate, and a merge switching valve for connecting a discharge pipe of the flow increasing pump to a discharge pipe of a standard pump when necessary are provided.

In the hydraulic circuit of the industrial machine, in a standard state, a standard pump supplies a standard flow rate of pressurized oil to the working device, so that the industrial machine can operate properly without impairing its performance. If the operating conditions of the working device change and a pressure oil with a larger flow rate than the standard flow rate is required, the changeover valve is switched to connect the discharge pipe of the high-pressure pump to the discharge pipe of the standard pump. Thus, the working oil can be supplied to the working device at a larger flow rate than the standard state.

[0008]

FIG. 1 is a hydraulic circuit diagram of a working vehicle which is an embodiment of a hydraulic circuit of an industrial machine according to the present invention.
This work vehicle includes a standard pump 2 driven by an engine PTO13 and a flow increasing pump 1. Standard pump 2
Is connected to the pump port P of the control valve 4 via the power steering 15, and the tank port T of the control valve 4 is connected to the oil tank 12 via the return line 21 via the return filter 11. It is connected. The cylinder ports A _l , B _l of the control valve 4 are connected to the oil chamber of the cylinder 6, and the cylinder ports A ₂ , B ₂ of the control valve 4 are connected to the oil chamber of the cylinder 5.

The discharge pipeline 22 of the booster pump 1 is normally connected to the return pipeline 21 from the control valve 4 to the oil tank 12 via the junction switching valve 3. By switching the discharge line 2 of the standard pump 2.
It is supposed to communicate with 0. This work vehicle uses a replaceable attachment 9 as a work device, and a working conduit 23 of the attachment 9 is connected to the PTO outlet 7 of the control valve 4 via the attachment operation valve 10. ing. The return line 24 of the attachment 9 is connected to the oil tank 12 via the return filter 11.

The attachment operation valve 10 is a two-position electromagnetic switching valve. The PTO outlet 7 is always in communication with the oil tank 12, and an operator sends an operation signal to the solenoid to operate the attachment operation valve 1.
0 is switched to operate the attachment 9. Working line 23 and return line 24 of attachment 9
The quick couplers 8 and 14 are provided in the middle of each of them so that various attachments can be easily replaced and used as a working device.

When the attachment 9 is of a standard type, the junction switching valve 3 is in the state shown in the figure, and the pressure oil discharged from the flow increasing pump 1 returns to the oil tank 12 through the return filter 11. In such a standard state, a standard flow rate of hydraulic oil discharged from the standard pump 2 is supplied to the cylinder 5, the cylinder 6, and the attachment 9, so that the flow rate does not become excessive and the original performance of the machine is not impaired. .

When another attachment that requires a pressure oil having a flow rate larger than the flow rate in the standard state is attached instead of the attachment 9, the switching valve 3 for the confluence is switched so that the discharge pipe of the flow increasing pump 1 is switched. Road 22 is standard pump 2
And the pressure oil discharged from the standard pump 2 and the pressure oil discharged from the booster pump 1 merge, so that a large amount of pressure oil flows into the cylinder 5, cylinder 6, and Supplied to the attachment.

Therefore, the required flow rate is ensured even when a large flow rate attachment is used, so that an attachment which could not be used due to insufficient flow rate can be used, and the working range of the work vehicle is expanded.

[0014]

As described above, the hydraulic circuit of an industrial machine according to the present invention can exhibit the original performance of the machine by supplying the standard flow rate of the hydraulic oil in the standard state. It is possible to secure a larger amount of pressure oil than in the state.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a work vehicle which is an embodiment of a hydraulic circuit of an industrial machine according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Increasing pump 2 Standard pump 3 Merging switching valve 4 Control valve 5 Cylinder 6 Cylinder 7 PTO outlet 8 Quick coupler 9 Attachment 10 Attachment operation valve 11 Return filter 12 Oil tank 13 Engine PTO 14 Quick coupler 15 Power steering 20 Discharge pipe Channel 21 Return line 22 Discharge line 23 Working line 24 Return line

Claims (1)

[Claims] 1. An industrial machine equipped with a hydraulically operated working device, a standard pump for supplying a standard flow of pressurized oil, and a flow increasing pump capable of supplying a pressurized oil of a difference flow between the standard flow and a required large flow. A hydraulic circuit for an industrial machine, comprising: a merged switching valve for connecting a discharge line of a booster pump to a discharge line of a standard pump when necessary.