JP3503059B2 - Hydraulic circuit of pile auger lifting device - 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 of an auger lifting device for a pile driver.

[0002]

2. Description of the Related Art In a pile driving machine, the pinions of an even number of hydraulic motors mounted as lifting devices in an auger rotary drive are engaged with teeth on both sides of a rack provided on a leader, and the auger rotates by the rotation of the hydraulic motors. An auger elevating device is configured by a device that raises and lowers the drive device along the leader, sprockets provided above and below the leader, a chain that is stretched over both sprockets, and an even number of hydraulic motors that rotate one of the sprockets. There is one in which both ends of a chain are connected to the upper and lower sides of an auger rotation drive device, and a hydraulic motor rotates a sprocket to move the auger rotation drive device up and down along a leader.

[0003]

When constructing steel pipe piles with spiral blades with these pile driving machines, the descending speed of the auger rotation drive device follows the screwing speed of the steel pipe piles.
The rotation speed of the lifting hydraulic motor is adjusted in the power down mode, but the steel pipe pile may be pulled in by the thrust of the spiral blade of the steel pipe pile depending on the ground. At this time, the operator responds by switching the rotation of the hydraulic motor to the free descent mode.However, since the hydraulic motor is located at a place far away from the tank mounted on the base machine, the rotation of the hydraulic motor is prevented by pulling in the steel pipe pile. The hydraulic motor sucks the hydraulic oil in the tank through a long hose, and cavitation easily occurs.

Therefore, the present invention provides a hydraulic circuit of an auger lifting device for a pile driving machine, which can follow the descending speed of the auger rotary drive device with a simple operation when the screwing speed of the steel pipe pile becomes fast. Is intended.

[0005]

In order to achieve the above object, the present invention provides an auger rotation by driving an even number of hydraulic motors having a circuit in which descending flow passages and ascending flow passages are connected in parallel. In a hydraulic circuit of an auger lifting device for a pile driver that raises and lowers a drive unit along a leader, a down-side switching valve is provided in a circuit that connects the down-side flow passages, and the down-side switching valve includes one hydraulic motor. A circuit branching from the ascending side flow path is connected, and a switching valve is provided in the ascending side circuit that connects the ascending side flow paths, and a circuit branching from the descending side path of one hydraulic motor is provided at the ascending side switching valve. It is characterized in that a circulation circuit is formed between the hydraulic motors by connecting and switching operation of both switching valves. Further, a pressure control valve or a flow rate control valve may be provided in the circuit branched from the descending side flow path.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the embodiments shown in the drawings. 1 to 4 show a first embodiment of the present invention, in which two hydraulic motors 4 mounted on the auger rotation driving device 3 as lifting devices are provided on the teeth on both sides of a rack 2 provided on a reader 1. The respective pinions 5 of 4 are engaged with each other, and the auger rotation drive device 3 is moved up and down along the reader 1 by the rotation of the hydraulic motors 4 and 4.

The drive circuit 6 for the hydraulic motors 4, 4 includes a descending passage 8 and an ascending passage 9 extending from the control valve 7.
Are branched at the ends of the counter balance valve 10. The branched descending flow paths 8a and 8b are connected to the hydraulic motors 4 and 4, respectively.
The ascending-side flow passages 9a and 9b are connected to the descending-side ports 4a of the hydraulic motors 4 and 4, respectively.
Further, the counter balance valve 10 is connected to a brake release valve 12 that is electrically operated to release the brakes 11 of the hydraulic motors 4 and 4.

A descending side switching valve 13 is provided between the descending side passages 8a and 8b, and a circuit 9c branched from the ascending side passage 9a of one hydraulic motor 4 is connected to the descending side switching valve 13. ing. Further, the ascending-side switching valve 14 is provided in the ascending-side flow passages 9a and 9b, and the ascending-side switching valve 14 is connected to a circuit 8c that branches from the descending-side flow passage 8a of one hydraulic motor 4. . The circuit 8c is provided with a variable relief valve 15 as a pressure control valve.

In the power down mode shown in FIG. 2, this drive circuit puts the down-side switching valve 13 into communication with the down-side flow paths 8a and 8b and the up-side switching valve 14 into the up-side flow paths 9a and 9b. By keeping the communication state, the hydraulic fluid is
It is supplied from the descending side flow paths 8a and 8b to the descending side ports 4a of the hydraulic motors 4 and 4, respectively, and the ascending side ports 4b of the hydraulic motors 4 and 4 respectively.
Through the ascending side flow paths 9a and 9b and the ascending side flow path 9 to return to the tank.

When the free lowering mode is set in a situation such as pulling in the steel pipe pile, as shown in FIG. 1, the brake release valve 12, by switching the switch to the free lowering mode in the neutral state of the control valve 7, The descending side switching valve 13 and the ascending side switching valve 14 are switched. This allows
The brakes 11, 11 of the hydraulic motors 4, 4 are released and the hydraulic motors 4, 4 are free to rotate. Further, the descending side passage 8a of one hydraulic motor 4 communicates with the ascending side passage 9b of the other hydraulic motor 4, and the ascending side passage 9a of one hydraulic motor 4 descends the other hydraulic motor 4. A circulation circuit is formed between the hydraulic motors 4 and 4 so as to communicate with the side flow passage 8b.

When the auger rotation drive device 3 descends due to the pulling in of the steel pipe pile, the hydraulic oil of the hydraulic motors 4, 4 is pushed out from the respective rising side ports 4b, and the hydraulic oil of one hydraulic motor 4 becomes the other hydraulic motor. No. 4, the hydraulic oil of the other hydraulic motor 4 flows to the descending side port 4a of the one hydraulic motor 4, respectively. Thereby, the descending speed of the auger rotation drive device 3 can be made to follow the descending speed of the steel pipe pile.

Therefore, since the hydraulic oil circulates in the short circuit between the hydraulic motors 4 and 4, the hydraulic oil in the tank is not sucked through the long hose, and the hydraulic motors 4 and 4 may be damaged due to the occurrence of cavitation. There is no. Further, a complicated structure such as increasing the number of pipes to the pile driver main body is not required.

The variable relief valve 15 has a set pressure so that the auger rotation drive device 3 can hold its own weight. The drive device 3 is safe without dropping and can follow the descending speed of the steel pipe pile without any problem even when the propulsive force of the steel pipe pile is applied.

Further, as in the second embodiment shown in FIG. 5, a variable throttle valve 16 is provided as a flow control valve in place of the variable relief valve 15, and the variable throttle valve 16 is set to a slow speed. In other words, in the case similar to the above, the auger rotation drive device 3 does not drop at a rapid speed.

In each of the above embodiments, two hydraulic motors have been described, but the present invention can be applied to an even number of hydraulic motors such as four and six hydraulic motors.

Further, as shown in FIGS. 6 and 7, two chains 20 and 20 provided along the leader 1 are connected to the upper and lower sides of the auger rotation driving device 3, and two hydraulic motors below the leader 1 are connected. The present invention is also applicable to a pile driving machine that raises and lowers the auger rotation drive device 3 along the leader 1 by rotating the sprocket wheels 21 and 21 of 4, 4 respectively.

[0017]

As described above, the hydraulic circuit of the auger lifting device for the pile driver of the present invention connects the descending side flow paths of the even number of hydraulic motors for moving the auger rotary drive device up and down along the leader. The down-side switching valve is installed in the circuit that connects to the down-side switching valve, the circuit that branches from the up-side flow path of one hydraulic motor is connected, and the up-side switching valve is installed in the circuit that connects the up-side flow paths. Since the circuit that branches from the lower flow path of one hydraulic motor was connected to the side switching valve, switching the lower switching valve and the upper switching valve to the free lowering mode causes the auger rotation drive device to lower by pulling in the steel pipe pile. In this case, the hydraulic oil of each hydraulic motor circulates in a short circuit between the hydraulic motors, and causes the descending speed of the steel pipe pile to follow the descending speed of the auger rotation drive device. Therefore, the hydraulic oil in the tank is not sucked through the long hose, and there is no risk of damage to the hydraulic motor due to cavitation. Moreover, a complicated structure such as an increase in the number of pipes is not required.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a first embodiment in a free descent mode.

[Fig. 2] Similarly, a hydraulic circuit diagram for holding a power down mode

FIG. 3 is a side view of a rack and pinion type auger rotation drive device.

FIG. 4 is a front view of a rack and pinion type auger rotation drive device.

FIG. 5 is a hydraulic circuit diagram of a second embodiment in which a free descent mode is maintained.

FIG. 6 is a side view of a chain drive type auger rotation drive device.

[Figure 7] Similarly, front view

[Explanation of symbols]

1 ... Leader, 2 ... Rack, 3 ... Auger rotation drive device, 4
... hydraulic motor, 5 ... pinion, 6 ... hydraulic motor drive circuit, 8, 8a, 8b ... descending side flow path, 8c ... branched circuit, 9, 9a, 9b ... rising side flow path, 9c ... branched circuit, 13 ... Downward switching valve, 14 ... Upward switching valve, 15 ...
Variable relief valve, 16 ... Variable throttle valve

Claims (3)

(57) [Claims] 1. An auger lifting device for a pile driver that drives an auger rotation drive device up and down along a leader by driving an even number of hydraulic motors having a circuit in which descending flow passages and rising flow passages are connected in parallel. In this hydraulic circuit, a descending side switching valve is provided in the circuit that connects the descending side flow passages, and a circuit branching from the ascending side passage of one hydraulic motor is connected to the descending side switching valve. An ascending side switching valve is provided in the circuit that connects the paths, and a circuit that branches from the descending side flow path of one hydraulic motor is connected to the ascending side switching valve, and a circulation circuit is provided between the hydraulic motors by switching operation of both switching valves. A hydraulic circuit of an auger lifting device for a pile driver, which is characterized in that 2. The hydraulic circuit of the auger lifting device for a pile driving machine according to claim 1, wherein a pressure control valve is provided in a circuit branched from the descending side flow passage. 3. The hydraulic circuit of the auger lifting device for a pile driving machine according to claim 1, wherein a flow control valve is provided in a circuit branched from the descending side flow passage.