JP2556641Y2 - Backhoe working vehicle hydraulic circuit - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit for a backhoe working vehicle.

[0002]

2. Description of the Related Art Generally, a backhoe working vehicle is shown in FIGS.
As shown in FIG. 1, a revolving unit 4 is provided on a traveling unit 3 having a pair of left and right traveling units 1 and 2 so as to be revolvable by a revolving unit 5, and a boom 6 is provided by a boom swing cylinder 7 in front of the revolving unit 4. An arm 9 is provided at the tip of the boom 6 so as to be rotatable by an arm cylinder 10 and can be pivoted horizontally and raised and lowered by a boom cylinder 8.
A bucket 11 is provided at the tip so as to be rotatable by a bucket cylinder 12.

[0003] In the drawing, reference numeral 13 denotes an earth discharging plate mounted so as to be driven by an earth discharging plate cylinder 14 in front of the traveling body 3.

As shown in FIG. 2, the hydraulic circuit of the backhoe working vehicle shown in FIGS.
4, the boom swing operation valve V1, the boom operation valve V2, and the bucket operation valve V3 are connected in parallel to the first hydraulic pump P1, and the second travel operation valve V7, the swing operation valve V9, the arm operation valve V8, and the earth discharging plate are connected. Operating valve V6 and second hydraulic pump P
2 and one of the pair of left and right traveling devices 1 and 2 (the traveling motor M2 in the example of the figure) is connected to the first traveling operation valve V4.
, A boom swing cylinder 7 for the boom swing operation valve V1, a boom cylinder 8 for the boom operation valve V2, a bucket cylinder 12 for the bucket operation valve V3, and the left and right for the second travel operation valve V7. The other of the pair of traveling devices 1 and 2 (the traveling device 1 provided with the traveling motor M1 in the example in the figure) is provided with a turning device 5 provided with a turning motor M3 on a turning operation valve V9, and an arm cylinder 1 provided on an arm operation valve V8.
0 is connected to the earthing plate operation valve V6 with the earthing plate cylinder 14 respectively.

[0005] In the figure, V5 is a preliminary operation valve.

[0006]

In the backhoe working vehicle as described above, the swing operation valve V9 and the arm operation valve V8 are simultaneously operated during excavation work or the like, and the arm 9 is rotated while the swing body 4 is swung. In this case, the hydraulic oil is supplied from the second hydraulic pump P2 to both the swing motor M3 of the swing device 5 and the arm cylinder 10 at the same time, so that the respective operating speeds of the swing motor M3 and the arm cylinder 10 are reduced. There was a problem that the work efficiency was reduced by half as compared with the time of the independent work.

[0007] In view of such circumstances, the present invention can maintain the respective operating speeds substantially equal to each other without halving even when the arm is operated at the same time as the turning of the revolving body, and improve the working efficiency. An object of the present invention is to provide a hydraulic circuit for a backhoe working vehicle.

[0008]

According to the present invention, at least a first travel control valve and a boom swing control valve are connected in parallel to a first hydraulic pump, and at least a second travel control valve, a swing control valve and an arm control valve are provided. Are connected in parallel to the second hydraulic pump, one of the pair of left and right traveling devices is connected to the first traveling control valve, the boom swing cylinder is connected to the boom swing operating valve, and the other of the pair of left and right traveling devices is connected to the second traveling control valve. In the hydraulic circuit of the backhoe working vehicle, in which the turning device is connected to the turning device and the arm cylinder is connected to the arm cylinder,
The two supply / discharge passages connecting the turning operation valve and the inlet / outlet port of the turning device are connected by a detection passage provided with a shuttle valve on the way, and the discharge passage of the first hydraulic pump and the second passage are connected to each other. A supply flow path from the hydraulic pump to the arm operation valve is connected by an auxiliary supply flow path, and a switching valve that opens with pressure oil from an outlet of the shuttle valve is provided in the auxiliary supply flow path. Is what you do.

[0009]

Therefore, when the turning operation valve and the arm operation valve are simultaneously operated to turn the arm while turning the revolving body during excavation work or the like, the operation of the turning operation valve causes the two supply / drain passages to be moved. The pressure oil from the second hydraulic pump flows to one of them, and the turning device is driven, and the pressure oil flows from the detection channel through the shuttle valve to the switching valve side as pilot pressure oil, thereby causing the switching. The valve is opened, and the pressure oil from the first hydraulic pump is supplied from the discharge flow path to the arm cylinder via the auxiliary supply flow path and the supply flow path, and the arm cylinder is driven, whereby the pressure in the supply flow path is increased. Since the pressure oil from the second hydraulic pump is increased by the pressure oil from the first hydraulic pump, most of the pressure oil from the second hydraulic pump is supplied to the turning device via the turning operation valve, and the turning body and the arm are each operated independently. Approximately the same speed To operate.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.
The same reference numerals as in FIG. 2 denote the same parts, and the basic configuration is the same as the conventional one shown in FIG. 2, but the feature of this embodiment is shown in FIG. as,
The turning operation valve V9 and the entrance / exit ports 15, 16 of the turning device 5
Are connected by a detection flow path 20 provided with a shuttle valve 19 on the way,
The discharge passage 21 of the first hydraulic pump P1 and the second hydraulic pump P
2 is connected to the supply flow path 22 communicating with the arm operation valve V8 by the auxiliary supply flow path 23, and the pressure oil 24 from the outlet of the shuttle valve 19
In that a switching valve 25 is provided.

In the figure, reference numeral 26 denotes a check valve provided in the middle of the supply passage 22 upstream of the connection point of the auxiliary supply passage 23,
Reference numeral 7 denotes a check valve provided in the middle of the auxiliary supply passage 23 downstream of the switching valve 25, and reference numeral 28 denotes a throttle provided in the middle of the auxiliary supply passage 23 downstream of the check valve 27.

With the above-described structure, when the turning operation valve V9 and the arm operation valve V8 are simultaneously operated to turn the arm 9 while turning the revolving body 4 during excavation work or the like, the turning operation valve V9 The second hydraulic pump P2 is connected to one of the two supply / discharge passages 17 and 18 by the operation of
The hydraulic oil flows from the detection valve 20 to drive the swivel device 5, and the hydraulic oil flows from the detection flow path 20 through the shuttle valve 19 to the switching valve 25 side as the pilot hydraulic oil 24, and the switching valve 2
5 is opened, and the pressure oil from the first hydraulic pump P1 is discharged from the discharge passage 2
1 to the arm cylinder 10 through the auxiliary supply channel 23, the supply channel 22 downstream of the check valve 26,
The arm cylinder 10 is driven.

As a result, the pressure in the supply passage 22 is increased by the pressure oil from the first hydraulic pump P1.
Most of the pressure oil from the second hydraulic pump P2 is supplied to the turning device 5 via the turning operation valve V9.

In this way, even if the arm 9 is operated at the same time as the revolving structure 4 is turned, the operating speeds are not reduced by half compared to the time of the independent operation, and the operating speeds are maintained substantially equal to those of the independent operation. And work efficiency can be improved.

It should be noted that the hydraulic circuit of the backhoe working vehicle of the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention.

[0017]

As described above, according to the hydraulic circuit of the backhoe working vehicle of the present invention, even if the arm is operated at the same time as the turning of the revolving body, each operating speed is substantially the same without being reduced by half compared to the case of the independent operation. , And an excellent effect that the work efficiency can be improved can be achieved.

[Brief description of the drawings]

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

FIG. 2 is a hydraulic circuit diagram of a conventional example.

FIG. 3 is a left side view of a general backhoe working vehicle.

FIG. 4 is a right side view of a general backhoe working vehicle.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 traveling device 2 traveling device 5 turning device 7 boom swing cylinder 10 arm cylinder 15 entrance port 16 entrance port 17 supply / discharge channel 18 supply / discharge channel 19 shuttle valve 20 detection channel 21 discharge channel 22 supply channel 23 auxiliary supply Flow path 24 Pressure oil 25 Switching valve P1 First hydraulic pump P2 Second hydraulic pump V1 Boom swing operating valve V4 First traveling operating valve V7 Second traveling operating valve V8 Arm operating valve V9 Turning operating valve

Claims (1)

(57) [Scope of request for utility model registration] At least a first travel control valve and a boom swing control valve are connected in parallel to a first hydraulic pump,
At least a second travel control valve, a swing control valve, and an arm control valve are connected in parallel to the second hydraulic pump, and one of the pair of left and right travel devices is connected to the first travel control valve, and a boom swing cylinder is connected to the boom swing control valve. In a hydraulic circuit of a backhoe working vehicle in which the other of the pair of left and right traveling devices is connected to the second traveling operation valve, the turning device is connected to the turning device, and the arm cylinder is connected to the arm cylinder, the turning operation valve and the turning device are The two supply / discharge flow paths connecting the entrance / exit port are connected by a detection flow path provided with a shuttle valve in the middle, and the discharge flow path of the first hydraulic pump and the second hydraulic pump lead to the arm operation valve. A backhoe connected to the supply flow path by an auxiliary supply flow path and provided with a switching valve in the middle of the auxiliary supply flow path, the switching valve being opened by pressure oil from an outlet of the shuttle valve. Hydraulic circuit of the working vehicle.