JPH018601Y2 - - Google Patents

Description

[Detailed description of the invention] This invention enables straight-line traveling with excellent stability by driving the hydraulic motors for driving each of the left and right traveling devices separately by two main pumps. In addition, if you want to drive the dozer's fluid pressure cylinder that drives up and down the earth removal plate with an auxiliary pump that is different from the two main pumps mentioned above, and move straight ahead while raising and lowering the earth removal plate. However, for details on the fluid pressure circuit of the dozer/backhoe work vehicle that prevents the aircraft from tilting, please see 2.
A bucket, an arm, and a boom are swung in order on a traveling machine base equipped with left and right traveling devices each driven by separate traveling fluid pressure motors, and a soil removal plate that can be raised and lowered by a dozer fluid pressure cylinder. A swivel base equipped with a backhoe device that can be connected to the swivel table is mounted to be rotatably driven by a swivel hydraulic motor, and two main pumps separately connected to the traveling hydraulic motor and the dozer hydraulic cylinder are installed. The present invention relates to a fluid pressure circuit for a dozer/backhoe work vehicle, which is provided with an auxiliary pump connected to a dozer/backhoe vehicle.

In backhoe work, for example,
As described in Publication No. 163503, the fluid pressure motor is frequently used, the fluid pressure cylinder for boom lifting and lowering, and the fluid pressure cylinder for swinging the arm are driven by separate pumps. It is desirable to configure a circuit to prevent fluctuations in the operating speed of the boom and arm and the rotating speed of the swivel table due to the driving status of these motors and cylinders, and to enable highly accurate work. Even in a double backhoe work vehicle, configuring a fluid pressure circuit suitable for such backhoe work would require four pumps in addition to the pump for driving the dozer's fluid pressure cylinder, which had the disadvantage of increasing manufacturing costs. .

For this reason, in the fluid pressure circuit of a conventional dozer/backhoe work vehicle, two main pumps are connected to a traveling fluid pressure motor, a swing fluid pressure motor, a boom lifting/lowering fluid pressure cylinder, and an arm swinging fluid pressure circuit. A method has been adopted to reduce the number of required pumps to three by distributing and connecting the cylinders (for example, in the Japanese patent publication
(Refer to Publication No. 55-111534), there was a problem in that it was not possible to perform work with the same precision as a work vehicle intended only for backhoe work.

The present invention has been developed in view of the above-mentioned circumstances, and has the following features: There is little need to rotate the swivel table while driving the earth removal plate up and down during dozer work, and
Focusing on the fact that backhoe work and dozer work are not performed at the same time, by devising the connection structure between the two main pumps and the auxiliary pump, it is now possible to perform dozer work and backhoe work using three pumps. However, during backhoe work, the hydraulic motor for swinging, the hydraulic cylinder for lifting and lowering the boom, and the hydraulic cylinder for swinging the arm can be driven by separate pumps, and the operating speed of the boom or arm can be increased. The purpose of the present invention is to enable backhoe work to be performed at high speed and with high precision.

The characteristic structure of this invention to achieve the above purpose is as follows:
In the fluid pressure circuit of the above-mentioned dozer and backhoe work vehicle, a boom lifting hydraulic cylinder for swinging the boom up and down with respect to the swivel base is connected to one of the two main pumps, An arm swinging hydraulic cylinder for swinging the arm with respect to the boom is connected to the other main pump, and the swinging fluid pressure motor is connected to the auxiliary pump, and a swinging control of the swinging fluid pressure motor is connected. When the valve is in a neutral state, a boom speed increasing valve for supplying fluid from the auxiliary pump to the boom rising side passage in the boom lifting hydraulic cylinder is connected to the boom in the boom lifting hydraulic cylinder. The auxiliary pump is connected to the lifting control valve so that it can be operated simultaneously, and when the swing control valve and the boom speed increase valve are both in a neutral state, the fluid from the auxiliary pump is connected to the arm. A flow path is provided to supply the arm swinging control valve of the swinging fluid pressure cylinder, and this configuration provides the following effects.

That is, during backhoe work, the hydraulic cylinder for lifting and lowering the boom and the hydraulic cylinder for swinging the arm are each driven by two main pumps,
Since the swing hydraulic motor is driven by an auxiliary pump, the operating speed of the boom and arm and the swing speed of the swing base are less likely to fluctuate.

Also, even during backhoe work, when the swivel table is not rotated, the fluid from the auxiliary pump is
The operating speed of the boom or arm is increased because the fluid from one main pump that is supplied to the boom lifting/lowering hydraulic cylinder or the fluid from the other main pump that is supplied to the arm swinging hydraulic cylinder is merged. This makes it possible to efficiently perform excavation work while swinging the arm back and forth, or to lift the excavated earth and sand by raising the boom when transferring the excavated earth and sand from a location to be excavated to another location.

Furthermore, when the swivel base is not rotating, the fluid from the auxiliary pump is not distributed and supplied to the hydraulic cylinder for lifting the boom and the hydraulic cylinder for swinging the arm in a constant distribution, but rather to the hydraulic cylinder for lifting the boom. When the hydraulic cylinder for lifting the boom is not being driven to the rising side of the boom, it is supplied to the hydraulic cylinder for swinging the arm, so deep grooves etc. When excavating, the excavation time can be effectively shortened.

In other words, when excavating a trench, etc., normally the arm is oscillated to shovel dirt into the bucket, the boom is swung upwards to allow the bucket to escape upward from the trench, etc., and then the swivel table is The machine rotates and releases the excavated earth and sand to a designated location.
A series of operations can be performed at high speed, from raking earth and sand into the bucket to escaping from the grooves of the bucket after the earth and sand have been shoveled in, while making efficient use of the fluid from the auxiliary pump.

Therefore, according to the present invention, although it is a dozer and backhoe work vehicle equipped with a total of three pumps, backhoe work can be performed at high speed and with high precision.
In particular, when excavating deep trenches, etc., the excavation time can be effectively shortened.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

As shown in Figures 1 and 2, the hydraulic motor
A rotating base 2 is mounted on a traveling machine base equipped with a pair of left and right traveling crawlers 1a and 1b that can be driven separately at Ma and Mb.
is mounted so that it can be driven and rotated around the vertical axis _X1 by a hydraulic motor Mc, and the support arm 3a of the earth removal plate 3 is mounted on the front part of the traveling machine base so that it can be driven up and down by a hydraulic cylinder 4, and the swivel base is mounted. 2 is equipped with an engine 5 and a driver's seat 6, and is located in the center of the front side of the swivel base 2.
A boom support bracket 7 is installed so that it can be driven and rotated around the vertical axis X ₂ by a hydraulic cylinder 8, and a boom 9 is installed on the bracket 7 so that it can be driven up and down and swung around the horizontal axis by a hydraulic cylinder 10. , an arm 11 is attached to the boom 9 so as to be movable around a horizontal axis by a hydraulic cylinder 12;
1, a backhoe device is constructed by attaching a bucket 13 so that it can be driven and swung around a horizontal axis by a hydraulic cylinder 14, thereby providing a dozer and backhoe work vehicle capable of performing dozer work and backhoe work. has been configured.

For driving the various hydraulic actuators, a second
As shown in the figure, two main pumps Pa, Pb and 1
Auxiliary pumps Pc are provided directly connected to the engine 5,
One main pump Pa is connected to the left traveling crawler 1a.
Hydraulic motor Ma control valve Va for
and connect the control valve 15 of the arm swing cylinder 12 to the control valve Va.
is connected so that pressure oil is supplied to it in its neutral state. Also, the other main pump Pb
, the hydraulic motor for the right traveling crawler 1b
Connect the control valve Vb of Mb, and connect the control valve 16 of the boom lifting cylinder 10 and the control valve 17 of the bucket rocking cylinder 14 to the control valve Vb.
They are connected so that pressure oil is supplied in parallel to their neutral state.

Furthermore, the control valve 18 of the cylinder 4 for elevating the earth removal plate and the control valve Vc of the motor Mc for rotating the rotating table are connected in parallel to the auxiliary pump Pc, and fluid is supplied to the boom upward flow path R ₁ in the boom elevating cylinder 10. The boom speed increase valve 19 for supplying the boom speed is connected to the control valve for the swivel
The boom speed increasing valve 19 is connected to the boom control valve 16 so that it can be operated simultaneously with the boom control valve 16, and is connected to the boom control valve 16 so as to be supplied with pressure oil in its neutral state. A flow path _R2 is provided to supply pressure oil to the arm control valve 15 in the neutral state, and a state in which the swivel base rotation motor Mc is connected to the swivel base control valve Vc and for the rotation of the boom support bracket 7 is provided. By providing a control valve 20 that selectively switches between the state in which the hydraulic cylinder 8 is connected and the left and right traveling crawlers 1a and 1b being separately driven by two main pumps Pa and Pb, By configuring it so that it can move straight ahead, and by raising and lowering the soil removal plate 3 using an auxiliary pump Pc,
It is constructed so that it can move straight ahead even during dozer work. Also, during backhoe work,
By driving the boom 9, arm 11, and swivel base 2 separately with separate pumps Pa, Pb, and Pc, the work of operating the boom 9, arm 11, and swivel base 2 all at once is facilitated. Furthermore, even when the swivel base is not in operation, the boom 9 is configured to be able to move upward at a sufficiently high speed by effectively utilizing the pressure oil of the auxiliary pump Pc. By effectively utilizing the pressure oil of the auxiliary pump Pc when the platform 2 and boom 9 are inactive,
The arm 11 is designed to be able to swing at a sufficiently high speed. Furthermore, during the backhoe operation, by rotating the boom support bracket 7 in advance, it is possible to excavate a groove in the lateral side of the machine body.

Note that the present invention may be implemented using a pneumatic actuator.

In addition, in implementing this proposal, the control valve 18 for the earth removal plate or the control valve Vc for the swivel base
One of the two valves 18 or Vc may be connected to the auxiliary pump Pc, and the other valve 18 or Vc may be connected to the one valve 18 or Vc so as to be supplied with fluid in its neutral state.

Further, wheels may be used as the left and right traveling devices 1a and 1b.

Note that although reference numerals are written in the claims section of the utility model registration for convenience of comparison with the drawings, the present invention is not limited to the structure of the attached drawings by such entry.

[Brief explanation of the drawing]

The drawings show an embodiment of a fluid pressure circuit for a dozer/backhoe vehicle according to the present invention; FIG. 1 is a side view of the dozer/backhoe vehicle, and FIG. 2 is a hydraulic circuit. 1a, 1b...travel device, 2...swivel base, 3...
...Earth removal plate, 4, 10, 12...Fluid pressure cylinder,
9...Boom, 11...Arm, 13...Bucket, 15, 16, Vc...Control valve,
19...Boom speed increase valve, Pa, Pb...Main pump, Pc...Auxiliary pump, Ma, Mb, Mc...Fluid pressure motor, _R1 ...Boom upward flow path, _R2 ...
flow path.

Claims (1)

[Scope of utility model registration request] A bucket truck is mounted on a traveling machine base equipped with left and right traveling devices 1a and 1b that are driven separately by two hydraulic pressure motors Ma and Mb for traveling, and a soil removal plate 3 that can be driven up and down by a hydraulic cylinder 4 for a dozer. 13, arm 11, and boom 9 are connected in order to be able to swing. A swivel base 2 equipped with a backhoe device is attached to be rotatably driven by a swivel fluid pressure motor Mc, and is connected to the traveling fluid pressure motors Ma and Mb. In a fluid pressure circuit of a dozer/backhoe work vehicle that is provided with two main pumps Pa and Pb that are separately connected and an auxiliary pump Pc that is connected to the dozer fluid pressure cylinder 4, the two main pumps A boom lifting hydraulic cylinder 10 for lifting and lowering the boom 9 relative to the swivel base 2 is connected to one main pump Pb of Pa and Pb, and the other main pump Pa is connected to an arm relative to the boom 9. 11 is connected to the arm swinging fluid pressure cylinder 12, and the swinging fluid pressure motor Mc is connected to the auxiliary pump Pc, and the swinging control valve Vc of the swinging fluid pressure motor Mc is brought into a neutral state. At some point, the fluid from the auxiliary pump Pc is transferred to the boom rising side flow path _R1 in the boom lifting hydraulic cylinder 10.
A boom speed increasing valve 19 for supplying the boom speed is provided in conjunction with the boom elevating control valve 16 in the boom elevating fluid pressure cylinder 10 so as to be operable simultaneously therewith, and A flow path _R2 is provided for supplying fluid from the auxiliary pump Pc to the arm swinging control valve 15 of the arm swinging fluid pressure cylinder 12 when both the boom speed increasing valve 19 is in a neutral state. A fluid pressure circuit for a dozer and backhoe work vehicle characterized by the following.