JPH0653803U - Hydraulic circuit of construction machinery - Google Patents

Abstract

(57) [Abstract] [Purpose] Even if the capacity of the hydraulic pump of one hydraulic circuit is insufficient, the flow rate of the hydraulic circuit is increased by using another hydraulic pump installed. A bypass circuit 8 is connected from a front drive circuit 3 having a second hydraulic pump 6 to an attachment drive circuit 2 having a first hydraulic pump 4, and a switching valve 9 is provided in the front drive circuit 3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hydraulic circuit of a construction machine such as a pile driver and a traveling crane.

[0002]

[Prior art]

 This type of construction machine is equipped with multiple hydraulic circuits for different purposes, such as a hydraulic circuit for traveling and a hydraulic circuit for work, and each hydraulic circuit is equipped with a hydraulic pump. The actuator driven by is used in proportion to the discharge amount of the hydraulic pump provided in each hydraulic circuit.

However, recently, the attachments used by these construction machines have become large in size, and the capacity of the hydraulic pump that drives the attachments may not be able to fully exert their capabilities.

[0004]

[Problems to be solved by the device]

 In such a case, it may be possible to increase the size of the hydraulic pump or use an external hydraulic source, but it is difficult to increase the size of the pump due to space constraints. Also, the use of an external hydraulic pressure source is troublesome because a hydraulic unit is prepared each time.

Therefore, the present invention aims to provide a hydraulic circuit capable of fully exerting its capability by a mounted hydraulic pump even if a large attachment is used.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention provides a hydraulic circuit of a construction machine having a plurality of hydraulic circuits for different purposes, each of which has a hydraulic pump, and a bypass circuit communicating with each of the hydraulic circuits. However, a switching valve is provided in the bypass circuit.

[0007]

[Work]

 For example, in the pile driver, the hydraulic circuit for traveling, the hydraulic circuit for the stay cylinder, the front jack, the outrigger, etc. are not used during the work using the attachment.

Therefore, if these unused hydraulic circuits are connected to the hydraulic circuit for attachment via the bypass circuit, the flow rate of the hydraulic circuit for attachment can be increased.

[0009]

【Example】

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

FIG. 1 shows a first embodiment of the present invention. A hydraulic circuit 1 of a construction machine comprises an attachment drive circuit 2 such as a hammer and a front drive circuit 3, and the attachment drive circuit 2 includes , A first hydraulic pump 4 and a first control valve 5 are provided.

Further, the front drive circuit 3 is provided with a second hydraulic pump 6 and a second control valve 7, and between the second hydraulic pump 6 and the second control valve 7 the second drive pump of the attachment drive circuit 2 is provided. 1 A bypass circuit 8 communicating downstream of the control valve 5 is branched.

Further, the front drive circuit 3 is provided with a switching valve 9 for switching the pressure oil supplied from the second hydraulic pump 6 to the front drive circuit 3 and the bypass circuit 8. The switching valve 9 is provided with a solenoid valve 10 that connects and disconnects the second hydraulic pump 6 and the second control valve 7, and a solenoid valve 11 that connects and disconnects the second hydraulic pump 6 and the bypass circuit. Has been.

With this configuration, when the capacity of the first hydraulic pump supplied to the attachment drive circuit 2 is insufficient, the solenoid valve 10 of the switching valve 9 is closed and the solenoid valve 11 is opened. The pressure oil from the second hydraulic pump 6 can be supplied to the attachment drive circuit 2, and the flow rate of the attachment drive circuit 2 can be increased.

Therefore, even if a large attachment is used, its ability can be fully exhibited.

FIG. 2 shows a second embodiment of the present invention, in which the hydraulic circuit 20 has substantially the same configuration as that of the first embodiment, and the switching valve 21 includes a solenoid valve 22. The pressure oil supplied from the second hydraulic pump 6 is switched to the front drive circuit 3 and the bypass circuit 8.

In the hydraulic circuit 30 of FIG. 3, the manual switching valve 31 switches the pressure oil supplied from the second hydraulic pump 6 to the front drive circuit 3 and the bypass circuit 8. An example is shown.

[0017]

[Effect of device]

 As described above, the hydraulic circuit of the present invention is provided with the bypass circuit which communicates between the hydraulic circuits each having a hydraulic pump and for different purposes of use, and the switching valve is provided in the bypass circuit. When the capacity of the hydraulic pump used is insufficient, connecting the unused hydraulic circuit to the used hydraulic circuit via a bypass circuit will increase the flow rate of the used hydraulic circuit. For example, when a large attachment is used, it can be covered by the installed hydraulic pump without adding a hydraulic pump.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a hydraulic circuit diagram showing a third embodiment of the present invention.

[Explanation of symbols]

1, 20, 30 ... Hydraulic circuit, 2 ... Attachment drive circuit, 3 ... Front drive circuit, 4 ... First hydraulic pump, 5 ...
1st control valve, 6 ... 2nd hydraulic pump, 7 ... 2nd control valve, 8 ... Bypass circuit, 9, 21,
31 ... Switching valve

Claims (1)

[Scope of utility model registration request] 1. A hydraulic circuit of a construction machine, wherein a plurality of hydraulic circuits having different purposes of use are provided with hydraulic pumps respectively.
A hydraulic circuit for a construction machine, wherein a bypass circuit communicating with each of the plurality of hydraulic circuits is provided, and a switching valve is provided in the bypass circuit.