JP2009001982A - Hydraulic circuit of auger lifting and lowering equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic circuit of auger lifting and lowering equipment with an auger free-descent mechanism capable of avoiding the breakage of a hydraulic motor in a free-fall state and preventing the free fall of an auger rotary-drive unit. <P>SOLUTION: The auger rotary-drive unit is provided in a vertically movable manner in a leader. The hydraulic circuit of the auger lifting and lowering equipment makes the auger rotary-drive unit lifted and lowered by the hydraulic motor 18 which is operated by a hydraulic fluid supplied from a hydraulic pump 23 via a control valve 25 and a load holding valve 26. A cross relief valve 27 which makes relief pressure switchable is provided between the hydraulic motor and the load holding valve. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydraulic circuit for an auger elevating device, and more particularly to a hydraulic circuit for driving a hydraulic motor for elevating and lowering an auger elevating device provided on a leader of a pile driver so as to move up and down.

When constructing a steel pipe pile or auger screw with a spiral blade at the tip, the auger rotation drive apparatus determined by the weight of the auger rotation drive apparatus including the steel pipe pile or auger screw and the propulsive force of the steel pipe pile or auger screw An auger-free lowering mechanism that lowers the auger with the weight and the propulsive force regardless of the amount of oil supplied to the hydraulic motor for raising and lowering the auger is known (see, for example, Patent Documents 1 and 2). .
JP 2001-98879 A Japanese Patent No. 3119343

  However, in the auger-free descending mechanism described in Patent Document 1, when the auger-free descending mechanism is operated with an excessive pushing force applied to the steel pipe pile or auger screw and the front part of the main body is floating, the hydraulic motor is forced upward. However, the suction flow rate of the hydraulic motor becomes insufficient due to the action of the flow control valve or relief valve that constitutes the auger-free lowering mechanism, and negative pressure is generated in the ascending circuit of the hydraulic motor, causing the hydraulic motor to rotate. Could be damaged.

  On the other hand, in the auger-free lowering mechanism described in Patent Document 2, when the auger-free lowering mechanism is operated, the auger rotation driving device is completely in a free-falling state. If operated, there is a risk that the auger rotation drive device will fall, negative pressure may be generated in the descent circuit of the hydraulic motor, or the hydraulic motor may suddenly rotate and seize, causing damage to the hydraulic motor. there were.

  Therefore, an object of the present invention is to provide a hydraulic circuit for an auger lifting device having an auger free lowering mechanism that can prevent a hydraulic motor from being damaged in a free lowering state and prevent a free fall of the auger rotation driving device.

  In order to achieve the above object, the hydraulic circuit of the auger elevating device according to the present invention includes an auger rotation driving device provided on a reader so as to be movable up and down by hydraulic oil supplied from a hydraulic pump via a control valve and a load holding valve. In the hydraulic circuit of the auger lifting device that is lifted and lowered by an operating hydraulic motor, a cross-relief valve is provided between the hydraulic motor and the load holding valve so that the relief pressure can be switched.

  Furthermore, the hydraulic circuit of the auger lifting device according to the present invention can be switched between a high pressure set value in which the relief pressure of the cross relief valve is higher than the discharge pressure of the hydraulic pump and a low pressure set value lower than the discharge pressure of the hydraulic pump. The relief pressure is switched to the low pressure set value when the low pressure setting switch is turned on and the control valve is operated to the lowered position. It is said.

  According to the hydraulic circuit of the auger lifting device of the present invention, when the auger free lowering mechanism is operated by setting the set pressure of the cross relief valve at the time of lowering the auger rotation driving device to the optimum relief pressure. The cross relief valve can be opened, and hydraulic oil can be circulated and supplied to the descending circuit from the ascending circuit of the hydraulic motor that is forced to rotate downward by the propulsive force.

  FIG. 1 is a circuit diagram of a main part showing a first embodiment of a hydraulic circuit of an auger lifting device of the present invention, and FIG. 2 is a side view showing an example of a pile driving machine equipped with an auger rotation driving device.

  First, as shown in FIG. 2, a pile driving machine 12 for embedding and constructing a steel pipe pile 11 having a spiral blade 11a at the tip is set up at the front part of an upper turning body 14 that is turnably provided on a lower traveling body 13. The auger rotation driving device 17 provided on the leader 15 is supported by the backstay 16 and can be moved up and down so as to be moved up and down by the hydraulic motor 19 of the auger lifting device 18 provided in the reader 15 via the chain 18a. Is formed. The steel pipe pile 11 is embedded by rotating the auger rotation driving device 17 by hydraulic pressure to rotate the steel pipe pile 11 and operating the hydraulic motor 19 of the auger lifting / lowering device 18 by hydraulic pressure to lower the auger rotation driving device 17. Is done.

  As shown in FIG. 1, the hydraulic circuit for operating the hydraulic motor 19 includes a control valve 25, a load holding unit between an ascending circuit 21 and a descending circuit 22 of the hydraulic motor 19, a hydraulic pump 23 and a tank 24. The valve 26 and the cross relief valve 27 are arranged, and the hydraulic motor 19 is raised by operating the control valve 25 with the operation lever 28 and switching the supply direction of the hydraulic pressure between the ascending circuit 21 and the descending circuit 22. It can be rotated to the side or rotated to the lower side.

  The cross relief valve 27 is connected to a relief pressure switching circuit 31 for switching the relief pressure of the cross relief valve 27. The relief pressure switching circuit 31 includes a solenoid valve 32, a pilot valve 33, a descending operation detection switch 34, a low pressure setting switch 35, and an alarm 36. When the relief pressure switching circuit 31 is operated, the cross relief valve 27 is provided. The relief pressure of the relief valve 27a provided in is switched from the high pressure set value during normal operation to the low pressure set value during free descent.

  The high pressure set value and the low pressure set value set as the relief pressure of the relief valve 27a are normally set to be higher than the maximum discharge pressure of the hydraulic pump 23 so that the relief valve 27a does not open during normal burying construction. Set to On the other hand, the low pressure set value is a pressure at which the relief valve 27a can be opened by the hydraulic pressure of the hydraulic oil supplied from the hydraulic pump 23, that is, a pressure equal to or lower than the discharge pressure of the hydraulic pump 23, and the steel pipe pile 11 is In the hydraulic pressure generated by the downward force in the rotational direction applied to the hydraulic motor 19 due to the weight of the held auger rotation driving device 17, that is, the hydraulic pressure acting on the relief valve 27a from the hydraulic motor 19 through the upward circuit 21 at this time. The pressure range is set so that the relief valve 27a does not open.

  In this embodiment, the high pressure set value is obtained when the relief chamber 27a is closed, and the low pressure set value is the relief pressure of the pilot valve 33 that communicates with the pilot chamber of the relief valve 27a when the relief pressure switching circuit 31 is operated. It is formed to set by adjusting.

  When the steel pipe pile 11 is buried with the low pressure setting switch 35 turned off (the state shown in FIG. 1), the control valve 25 is lowered by the operation lever 28 while the steel pipe pile 11 is rotated by the auger rotation drive device 17. Switch to position 25a. Thereby, the hydraulic oil from the hydraulic pump 23 is supplied toward the descending circuit 22 through the flow path of the descending position 25a.

  When the hydraulic pressure acts on the lower side of the load holding valve 26, the brake 19a is released by the brake release circuit 26a, the hydraulic motor 19 can be rotated, and the upward release valve 26c is applied by the action of the hydraulic pressure to the upward release circuit 26b. Opens. The hydraulic oil passes through the descending check valve 26d of the load holding valve 26, passes through the cross relief valve 27, and is supplied to the descending circuit 22 of the hydraulic motor 19, and rotates the hydraulic motor 19 to the descending side to raise the circuit 21. To leak.

  The hydraulic fluid flowing in the reverse direction in the ascending circuit 21 passes through the cross relief valve 27 and returns to the tank 24 through the flow path of the ascending release valve 26c of the load holding valve 26 and the descending position 25a of the control valve 25. The hydraulic motor 19 is rotated downward by the flow of the hydraulic oil, and the amount of discharge from the hydraulic pump 23 is controlled to lower the auger rotation driving device 17 in synchronization with the excavation speed of the steel pipe pile 11, or the steel pipe An appropriate pushing force can be applied to the pile 11.

  At this time, the pressure of the hydraulic oil flowing through the descending side circuit 22 acts on the relief valve 27a of the cross relief valve 27, but the low pressure setting switch 35 is turned off and the relief pressure switching circuit 31 is not operated. Since the chamber is in a closed state and the relief pressure of the relief valve 27a is a high pressure set value set to be equal to or higher than the discharge pressure of the hydraulic pump 23, the relief valve 27a is always closed.

  When the control valve 25 is switched to the neutral position 25b (the state shown in FIG. 1), the ascending circuit 21 and the descending circuit 22 are both released to the tank 24 through the control valve 25, and the ascending circuit The hydraulic pressure does not act on any of 21 and the descent side circuit 22, and the brake 19a enters the braking state when the hydraulic pressure is released from the brake release circuit 26a of the load holding valve 26, and the ascending side release circuit 26b and the descent side release circuit. Since the hydraulic pressure does not act on 26e, the ascending release valve 26c and the descending release valve 26f are closed.

  At this time, the weight of the auger rotation drive device 17 including the steel pipe pile 11 is acting on the hydraulic motor 19 in the downward rotation direction, but the load holding valve 26 is closed and the brake 19a is in a braking state. Since the load holding valve 26 is closed and the flow of hydraulic fluid is also blocked, the hydraulic motor 19 does not rotate, and the auger rotation drive device 17 does not descend or rise.

  When an excessive load is applied to the hydraulic motor 19 for some reason while the auger rotation driving device 17 is descending or ascending, the pressure on the ascending side circuit 21 or the descending side circuit 22 rises. A relief valve (not shown) provided in the (hydraulic unit) is opened to avoid an abnormal pressure increase.

  When embedding the steel pipe pile 11 in a free descending state, the low pressure setting switch 35 of the relief pressure switching circuit 31 is turned on, and the operation lever 28 is operated to switch the control valve 25 to the descending position 25a. By operating the operation lever 28 to the lower side, the lowering operation detection switch 34 is turned ON to energize the solenoid of the solenoid valve 32, and the flow path of the solenoid valve 32 is released from the blocking position 32a (the state shown in FIG. 1). Switch to position 32b. As a result, the pilot chamber of the relief valve 27a communicates with the pilot valve 33 via the solenoid valve 32, and the relief pressure of the relief valve 27a is switched to the low pressure set value.

  When the control valve 25 is switched to the descending position 25a, the hydraulic oil from the hydraulic pump 23 passes through the load holding valve 26 and the cross relief valve 27 from the flow path at the descending position 25a of the control valve 25 as described above. Is supplied to the lowering circuit 22 of the hydraulic motor 19 to rotate the hydraulic motor 19 downward. The hydraulic fluid that has flowed out from the hydraulic motor 19 to the ascending side circuit 21 flows in the ascending side circuit 21 in the reverse direction, and returns to the tank 24 through the cross relief valve 27, the load holding valve 26, and the control valve 25. The amount of hydraulic oil discharged from the hydraulic pump 23 at this time is sufficient to allow the brake 19a to be released by the brake release circuit 26a and the rising side release valve 26c to be opened by the rising side release circuit 26b.

  A hydraulic motor 19 in which the lowering speed of the auger rotation driving device 17 determined by the weight of the auger rotation driving device 17 including the steel pipe pile 11 and the propulsive force of the steel pipe pile 11 is determined by the flow rate of the hydraulic oil supplied from the lowering side circuit 22. When the rotation speed is lower than the lowering speed, the hydraulic motor 19 is forcibly rotated to the lowering side by the lowering auger rotation driving device 17, and the hydraulic motor 19 is supplied with the amount of hydraulic oil supplied. Attempts to rotate downward at a high rotational speed. Accordingly, since the amount of hydraulic oil supplied is smaller than the rotation speed, the hydraulic oil in the lowering circuit 22 is sucked into the hydraulic motor 19 and the hydraulic pressure in the lowering circuit 22 is lowered.

  When the hydraulic pressure of the descending circuit 22 decreases, the hydraulic pressure acting on the ascending release circuit 26b of the load holding valve 26 decreases, so that the ascending release valve 26c closes and the hydraulic oil circuit returns from the ascending circuit 21 to the tank 24. Is cut off. As a result, the hydraulic pressure of the rising side circuit 21 is increased by the hydraulic oil discharged from the hydraulic motor 19, and the hydraulic pressure acting on the relief valve 27a is increased via the check valve 27b of the cross relief valve 27.

  As described above, the relief pressure of the relief valve 27a is set to a low pressure set value by operating the relief pressure switching circuit 31. Therefore, the relief valve 27a is opened by a slight increase in hydraulic pressure, and the ascending side circuit 21 is operated. The hydraulic fluid flows through the check valve 27b, the relief valve 27a and the check valve 27c to the descending circuit 22. Accordingly, since the hydraulic oil circulates to the hydraulic motor 19 through the cross relief valve 27, the descending side circuit 22 does not become negative pressure, and the auger rotation driving device 17 is lowered by the propulsive force of the steel pipe pile 11. The hydraulic motor 19 can be rotated at a rotational speed commensurate with the speed, and the steel pipe pile 11 can be buried in a free descending state.

  On the contrary, when the discharge amount from the hydraulic pump 23 is excessive with respect to the rotational speed of the hydraulic motor 19, the hydraulic pressure of the descending circuit 22 rises and the hydraulic pressure acts via the check valve 27d of the cross relief valve 27. The relief valve 27a is opened, and excess hydraulic oil in the descending circuit 22 passes through the check valve 27d, the relief valve 27a and the check valve 27e, flows into the ascending circuit 21 and returns to the tank 24, and the propulsive force of the steel pipe pile 11 The hydraulic oil 19 is supplied to the hydraulic motor 19 as much as it follows. As a result, the auger rotation driving device 17 descends due to the lowering speed determined by the weight of the auger rotation driving device 17 including the steel pipe pile 11 and the propulsive force of the steel pipe pile 11 and the slight hydraulic pressure applied to the hydraulic motor 19. It will be in the state where embedding of the pile 11 advances.

  When the control valve 25 is returned to the neutral position 25b by the operation lever 28 after the construction, the descending operation detection switch 34 is turned off even when the low pressure setting switch 35 is in the on state, so that the solenoid valve 32 is switched to the cutoff position 32a. . As a result, the pilot chamber of the relief valve 27a is closed, and the relief pressure of the relief valve 27a becomes the high pressure set value. Therefore, the raising of the auger rotation driving device 17 with the steel pipe pile 11 cut off can be performed as usual by switching the control valve 25 to the raising position 25c.

  Further, even when the control valve 25 is in the neutral position 25b with the auger rotation driving device 17 raised, the relief pressure of the relief valve 27a is a high pressure set value, so that the relief valve 27a is opened and the hydraulic oil is hydraulic. The motor 19 is not circulated, and the auger rotation driving device 17 does not fall freely. In addition, by operating the alarm 36 when the low pressure setting switch 35 is in the on state, the operator can recognize that the free drop is in progress, and be careful about forgetting to turn off the low pressure setting switch 35 after the free drop ends. Can be urged.

  On the other hand, when normal embedding is performed with the control valve 25 in the lowered position 25a without operating the relief pressure switching circuit 31, an excessive pushing force is applied to the steel pipe pile 11 due to the ground, and the front part of the main body. If the low pressure setting switch 35 is mistakenly turned on when the state becomes floating, the hydraulic motor 19 is forced to rotate upward (reverse rotation), and the hydraulic motor 19 is 21 hydraulic oil is sucked.

  At this time, since the low pressure setting switch 35 is turned on while the control valve 25 is in the lowered position 25a, the relief pressure switching circuit 31 is activated as described above, and the relief pressure of the relief valve 27a is applied to the pilot valve 33. The low pressure set value is set. Accordingly, the hydraulic oil supplied to the lower side circuit 22 from the hydraulic pump 23 and further the hydraulic oil discharged from the hydraulic motor 19 rotating in the reverse direction to the lower side circuit 22 increases the hydraulic pressure of the lower side circuit 22, and the cross The relief valve 27a of the relief valve 27 is opened, and the hydraulic oil in the descending circuit 22 flows to the ascending circuit 21 through the check valve 27d, the relief valve 27a and the check valve 27e, and the ascending circuit 21 becomes negative pressure. To prevent.

  FIG. 3 is a circuit diagram of a main part showing a second embodiment of the hydraulic circuit of the auger lifting device of the present invention. In the following description, the same configuration as the components of the hydraulic circuit shown in the first embodiment is shown. Elements are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the hydraulic circuit shown in the present embodiment, the cross-relief valve is replaced with the integrated cross-relief valve 27 shown in the first embodiment, and an ascending circuit 21 and a descending circuit 22 are connected. It is configured by a combination of a single pair of relief valves 51 and 52 provided, and the relief pressure of both relief valves 51 and 52 is switched by a combination of a solenoid valve 53 and a pair of pilot valves 54 and 55. It is composed.

  The pilot valves 54 and 55 have one pilot valve 54 for high pressure setting and the other pilot valve 55 for low pressure setting. Like the first embodiment, the high pressure setting pilot valve 54 is the relief valve. The relief valves 51 and 52 are set to open when the hydraulic pressure acting on the pressure pumps 51 and 52 becomes equal to or higher than the discharge pressure of the hydraulic pump 23, and the low pressure setting pilot valve 55 is hydraulic pressure acting on the relief valves 51 and 52. However, the relief valves 51 and 52 are set so as not to be opened by the hydraulic pressure generated by the lowering force in the rotational direction applied to the hydraulic motor 19 due to the weight of the auger rotation driving device 17.

  When the control valve 25 is switched to the lowered position 25a with the low pressure setting switch 35 turned off (the state shown in FIG. 3), the hydraulic oil discharged from the hydraulic pump 23 is supplied to the control valve 25, the load holding valve 26, and the cross relief valve. 27 is supplied to the descending circuit 22 of the hydraulic motor 19, rotates the hydraulic motor 19 downward, flows out to the ascending circuit 21, flows in the reverse direction, and returns to the tank 24. At this time, since the flow path of the solenoid valve 53 is the high pressure side 53a communicating with the high pressure setting pilot valve 54, the relief pressures of the relief valves 51 and 52 are at the high pressure set value, and therefore always closed. It is in a state.

  When the low pressure setting switch 35 is turned on and the control lever 25 is operated to switch the control valve 25 to the lower position 25a, the lower operation detection switch 34 is turned on and the solenoid valve 53 is switched to the low pressure side 53b. The relief pressures of the valves 51 and 52 are switched to the low pressure set value set in the low pressure setting pilot valve 55.

  When the descent speed of the auger rotation driving device 17 by the propulsive force of the steel pipe pile 11 is fast and the hydraulic motor 19 is rotated to the lower side, the load holding valve 26 is closed and the higher side as in the first embodiment. Since the hydraulic pressure of the circuit 21 increases, one relief valve 51 that opens due to the increase in hydraulic pressure of the rising circuit 21 opens, and the hydraulic oil of the rising circuit 21 flows to the lower circuit 22 through the relief valve 51, Circulates to the motor 19. Thereby, the steel pipe pile 11 can be laid in a free descending state while preventing the descending circuit 22 from becoming a negative pressure.

  Further, when the low pressure setting switch 35 is turned on with the front portion of the main body floating due to an excessive pushing force to the steel pipe pile 11 at the time of burial construction, the hydraulic motor 19 rotates reversely and the hydraulic pressure of the descending circuit 22 increases. Therefore, the other relief valve 52 that opens due to the increase in the hydraulic pressure of the descending circuit 22 is opened, and the hydraulic oil in the descending circuit 22 flows to the ascending circuit 21 through the relief valve 52, and the ascending circuit 21 becomes negative pressure. To prevent becoming.

  As shown in both embodiments, a cross-relief valve 27 or a pair of relief valves 51 and 52 that allow the relief pressure to be switched between the hydraulic motor 19 and the load holding valve 26 is used as an auger-free lowering mechanism. The cross-relief valve is provided, and the relief pressure of the cross-relief valve is appropriately set between the high pressure and the low pressure, thereby preventing negative pressure from being generated in the ascending side circuit 21 and the descending side circuit 22. Thus, the hydraulic motor 19 can be reliably protected.

  Also, by setting the relief pressure on the high pressure side of the cross relief valve to be higher than the discharge pressure of the hydraulic pump 23, the cross relief valve will not open under normal operation. It can be carried out. Furthermore, by setting the relief pressure on the low pressure side of the cross relief valve so that the cross relief valve does not open with the hydraulic pressure generated from the hydraulic motor 19 due to the weight of the auger rotation drive device 17 including the steel pipe pile 11 or the auger screw, It is possible to prevent the raised auger rotation drive device 17 from falling freely.

  In addition, by allowing the free descent to be performed only when both the low pressure setting switch 35 and the descent operation detection switch 34 are turned on, erroneous operation can be reliably prevented, and an alarm 36 is provided. By operating the alarm 36 when the low pressure setting switch 35 is turned on, the operator can be informed that the low pressure setting switch 35 is turned on, and can be alerted not to forget to turn it off. .

  In both examples, the pile driving machine that embeds the steel pipe pile is illustrated, but the same applies to the pile driving machine that performs excavation with an auger screw, and the auger lifting device may use a rack and pinion. . Furthermore, depending on conditions such as the scale of the pile driver, the descent operation detection switch and the alarm device can be omitted. Moreover, a warning light and a warning sound can be used suitably for an alarm device, and multiple types can also be used together.

It is a circuit diagram of the principal part which shows the 1st form example of the hydraulic circuit of the auger raising / lowering apparatus of this invention. It is a side view which shows an example of the pile driving machine provided with the auger rotation drive device. It is a circuit diagram of the principal part which shows the 2nd form example of the hydraulic circuit of the auger raising / lowering apparatus of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Steel pipe pile, 11a ... Blade | wing, 12 ... Pile driver, 13 ... Lower traveling body, 14 ... Upper turning body, 15 ... Leader, 16 ... Backstay, 17 ... Auger rotation drive device, 18 ... Auger lifting device, 18a DESCRIPTION OF SYMBOLS ... Chain, 19 ... Hydraulic motor, 19a ... Brake, 21 ... Ascending side circuit, 22 ... Decreasing side circuit, 23 ... Hydraulic pump, 24 ... Tank, 25 ... Control valve, 25a ... Down position, 25b ... Neutral position, 25c ... Ascending position, 26 ... Load holding valve, 26a ... Brake release circuit, 26b ... Up side release circuit, 26c ... Up side release valve, 26d ... Down side check valve, 26e ... Down side release circuit, 26f ... Down side release valve, 27 ... Cross relief valve, 27a ... Relief valve, 27b, 27c, 27d, 27e ... Check valve, 28 ... Operation lever, 31 ... Relief pressure switching circuit, 3 ... Solenoid valve, 32a ... Shut-off position, 32b ... Open position, 33 ... Pilot valve, 34 ... Lowering operation detection switch, 35 ... Low pressure setting switch, 36 ... Alarm, 51, 52 ... Relief valve, 53 ... Solenoid valve, 53a ... High pressure side, 53b ... Low pressure side, 54,55 ... Pilot valve

Claims (3)

  In the hydraulic circuit of the auger elevating device, the auger rotation driving device provided in the leader so as to be movable up and down is moved up and down by a hydraulic motor operated by hydraulic oil supplied from a hydraulic pump via a control valve and a load holding valve. A hydraulic circuit for an auger lifting device, characterized in that a cross-relief valve is provided between the load holding valve and the load holding valve so that the relief pressure can be switched.   The relief pressure of the cross relief valve is configured to be switchable between a high pressure set value higher than the discharge pressure of the hydraulic pump and a low pressure set value lower than the discharge pressure of the hydraulic pump. Hydraulic circuit of the described auger lifting device.   3. The hydraulic pressure of the auger lifting / lowering device according to claim 2, wherein switching of the relief pressure to a low pressure set value is performed when a low pressure setting switch is turned on and the control valve is operated to a lowered position. circuit.

Images