JP6310239B2 - Shift control method for ground construction machine and ground construction machine - Google Patents

Description

  The present invention relates to a ground construction machine that performs excavation and ground improvement work on the ground by rotationally driving a tool such as an auger screw or a stirring tool, and more specifically, a shift control method in the ground construction machine. In a ground construction machine equipped with a hydraulic motor that can be changed continuously, the upper and lower limits of the tool drive torque can be set, and control is performed so that the optimum drive torque is between the upper and lower limits. The present invention relates to a ground construction machine and a speed change control method in the ground construction machine.

  Conventionally, a ground construction machine that rotates an auger screw to excavate the ground or rotates an agitating tool to improve the ground has been used. For example, when excavating the ground, it is necessary to set the drive torque and rotation speed of the tool (auger screw) to appropriate values according to the state of the ground to be excavated (soft, hard, etc.).

  In the ground construction machine, multiple gears with different relationships between the drive torque of the tool and the rotational speed are set, and the operator selects and sets the most appropriate gear from the gears according to the ground conditions. Things to do have been known for a long time. In addition, a ground construction machine that automatically performs the shift of such a shift stage is also known.

  The following Patent Document 1 describes a pile construction machine that performs excavation by selecting an appropriate one from a plurality of shift stages according to input information of an operator. Japanese Patent Application Laid-Open No. H10-228561 also describes that the gear position is automatically selected and the gear position is automatically changed in response to a change in the ground state during the excavation process. This automatic transmission technology requires a plurality of hydraulic motors capable of changing the displacement volume in stages.

  In Patent Document 2, a plurality of variable displacement hydraulic motors capable of changing the displacement volume to two stages of large and small are combined to form a five-stage shift stage, and the shift stage is automatically set between these shift stages. The shifting automatic transmission technology is described. This automatic transmission technology also requires a plurality of hydraulic motors that can change the displacement volume in stages.

JP 2008-240503 A JP 2011-69140 A

  In the ground construction machine, when the operator selects the optimum gear from a plurality of gears according to the ground condition, the worker accurately recognizes the ground condition, and which gear is appropriate. I had to judge exactly. For this reason, a high level of skill is required of the worker, and not everyone can easily handle the ground construction machine. In addition, although there is a technical idea of automatically selecting a gear position as in Patent Document 1, it has been difficult to realize a practical ground construction machine.

  In particular, as in Patent Document 1, when the optimum gear stage is selected only from the current tool driving torque, the driving torque changes rapidly at the moment of shifting, and further shifting occurs due to the torque fluctuation. There are many cases. In such a case, the shift stage may repeat many changes in a short time, and the shift control may not be stable. In addition, the tool itself may vibrate, and the tool and the ground construction machine may be damaged.

  In a ground construction machine such as Patent Document 2, not only the reference value of the pressure of the fluid that drives the hydraulic motor but also the time during which the pressure indicates the shift of the gear stage is taken into consideration, so that a practical and stable speed change can be achieved. Control is possible. However, in order to perform the shift control as in Patent Document 2, it is necessary to arrange a plurality of hydraulic motors that can change the displacement volume step by step, which increases the manufacturing cost of the ground construction machine. there were. In addition, if it is attempted to increase the number of shift stages in order to perform shift control more smoothly, it becomes necessary to increase the number of variable stages of the hydraulic motor or increase the number of hydraulic motors. Will rise further.

  Moreover, in a ground construction machine, when the ground load with respect to a tool is large and drive torque is insufficient, rotation of a tool may be restrained and it may be in a rotation stop state. In such a rotation stop state, even if an attempt is made to increase the drive torque of the tool by increasing the displacement volume of the hydraulic motor, the displacement volume may not change. That is, in such a rotation stop state, there is a problem in that automatic shift control may not function normally.

  Therefore, the present invention can set an upper limit value and a lower limit value of the drive torque of the tool in the ground construction machine having a hydraulic motor capable of continuously changing the displacement volume, and between the upper limit value and the lower limit value. It is an object of the present invention to provide a low-cost ground construction machine and a speed change control method for the ground construction machine that can stably and smoothly carry out transmission control so as to obtain an optimum driving torque.

  Further, the present invention determines that the rotation of the tool is constrained and is in a rotation stop state, and a ground construction machine capable of automatically returning from such a rotation stop state and performing gear shift control, and its An object of the present invention is to provide a speed change control method in a ground construction machine.

In order to achieve the above object, the shift control method in the ground construction machine of the present invention can continuously change the displacement tool and the tool for construction on the ground by rotational drive, and the tool is rotationally driven. Shift control in a ground construction machine comprising: a hydraulic motor that detects pressure of a fluid supplied to the hydraulic motor; and a rotation speed detector that detects a rotation speed of the hydraulic motor A method for setting an upper limit value and a lower limit value of a drive torque actually used for rotational driving of the tool within a range of drive torque that can be generated by the hydraulic motor; A procedure for setting a plurality of drive torques including the lower limit value and the upper limit value within a range equal to or less than a value, and a plurality of the hydraulic motors respectively corresponding to the set drive torques Procedure for obtaining displacement volume, and procedure for setting the reference value of the pressure for shifting from the displacement volume other than the lower limit volume corresponding to the lower limit value to the displacement volume smaller by one step as the lower reference value for each displacement volume And a procedure for setting the reference value of the pressure for shifting from the displacement volume other than the upper limit volume corresponding to the upper limit value to the displacement volume one step larger as the upper reference value for each displacement volume, and the displacement A procedure for setting a reference time for shifting from a volume to an adjacent displacement volume for each transition, and in a state where the hydraulic motor is at a predetermined displacement volume other than the lower limit value, the pressure is a lower reference value When the following state continues for a reference time or longer, a procedure for shifting to a one-step smaller displacement volume, and the hydraulic motor Wherein in a state at a predetermined the displacement other than the upper limit value, when a state wherein the pressure is equal to or greater than the upper reference value is continuously reference time or longer possess the procedure shifts to one stage higher displacement, the 1 When the displacement volume of the hydraulic motor is increased by one step in the procedure of shifting to a larger displacement volume, the rotational speed of the output shaft of the hydraulic motor is equal to or lower than a predetermined constraint reference speed and the pressure is equal to the predetermined constraint pressure. When the state that is equal to or greater than the reference value continues for a predetermined restraint reference time or longer, it is determined that the rotation of the tool is restrained, and the supply of fluid to the hydraulic motor is stopped before the displacement volume. And thereafter, a procedure for starting the supply of fluid to the hydraulic motor is executed .

  In the shift control method for the ground construction machine, the procedure for setting the plurality of drive torques may set eleven stages of drive torque including the lower limit value and the upper limit value.

  Further, in the above-described shift control method in the ground construction machine, the ground construction machine is provided to be movable along a rotation drive unit for transmitting the rotation output of the hydraulic motor to the tool and a guide leader. And a drive head in which the hydraulic motor and the rotation drive unit are arranged, and when the drive head is located at a predetermined position above the leader, the change range of the drive torque is smaller than the upper limit value. It is preferable to limit the second upper limit value or less.

  Further, in the shift control method in the ground construction machine, when the drive head is positioned at a predetermined position above the leader, a procedure for setting the second upper limit value that is smaller than the upper limit value; A procedure for setting a plurality of drive torque values including the lower limit value and the second upper limit value within a range equal to or less than the second upper limit value, and a plurality of hydraulic motors respectively corresponding to the set plurality of drive torque values Procedure for obtaining displacement volume, and procedure for setting the reference value of the pressure for shifting from the displacement volume other than the lower limit volume corresponding to the lower limit value to the displacement volume smaller by one step as the lower reference value for each displacement volume And the pressure for shifting from the displacement volume other than the upper limit volume corresponding to the second upper limit value to the displacement volume larger by one step. A procedure for setting a quasi value as an upper reference value for each displacement volume, a procedure for setting a reference time for transition from the displacement volume to an adjacent displacement volume for each transition, and the hydraulic motor In a state where the displacement is in a predetermined displacement other than the lower limit value, and the state where the pressure is equal to or lower than a lower reference value continues for a reference time or longer, a procedure for shifting to a displacement smaller by one step; It is preferable to have a procedure of shifting to a larger displacement volume by one step when a state where the pressure is equal to or higher than the upper reference value continues for a reference time or longer in a state where the displacement is a predetermined displacement other than the second upper limit value. .

Further, the ground construction machine of the present invention is a tool for constructing the ground by rotational driving, a displacement volume can be continuously changed, a hydraulic motor for rotationally driving the tool, and rotation of the hydraulic motor A rotary drive unit for transmitting an output to the tool, a drive head provided to be movable along a guide reader, the hydraulic motor and the rotary drive unit disposed therein, and a fluid supplied to the hydraulic motor A pressure detector for detecting the pressure of the hydraulic motor, a rotational speed detector for detecting the rotational speed of the hydraulic motor, and controlling the displacement of the hydraulic motor to generate an appropriate driving torque. A drive control unit for controlling the drive as described above. The drive control unit includes storage means for storing information, and the storage means is a drive torque that is actually used for rotationally driving the tool within a range of drive torque that can be generated by the hydraulic motor. And storing a plurality of drive torques including the lower limit value and the upper limit value in a range not less than the lower limit value and not more than the upper limit value, and for each of the set plurality of drive torques. A plurality of displacements of the corresponding hydraulic motor are stored, and a reference value of the pressure for shifting from the displacement other than the lower limit value to a displacement smaller by one step is set as a lower reference value for each displacement volume. The reference value of the pressure for shifting from the displacement volume other than the upper limit value to the displacement volume one step larger is used as the upper reference value. Storing for each displacement, a reference time for moving to displacement adjacent from the displacement volume is configured to store for each transition. In addition, the drive control unit may displace one step smaller when the hydraulic motor is in a predetermined displacement volume other than the lower limit value and the pressure is below the lower reference value for a reference time or longer. If the state where the pressure is higher than the upper reference value and the state where the pressure is higher than the upper reference value continues for a reference time or more in the state where the hydraulic motor is in the predetermined displacement volume other than the upper limit value, the displacement volume larger by one step When the displacement volume of the hydraulic motor is increased by one step, the rotational speed of the output shaft of the hydraulic motor is equal to or lower than a predetermined constraint reference speed and the pressure is equal to the predetermined constraint pressure reference. When the state that is greater than or equal to the value continues for a predetermined restraint reference time or longer, it is determined that the rotation of the tool is restrained, and the fluid to the hydraulic motor is The sheet to increase the displacement volume from the stop, then, is to take steps to initiate the supply of fluid to the hydraulic motor.

  In the above ground construction machine, the plurality of drive torques including the lower limit value and the upper limit value can be set to 11 stages of drive torque.

  Further, in the above ground construction machine, the drive control unit may set the change range of the drive torque value to be equal to or less than a second upper limit value smaller than the upper limit value when the drive head is positioned at a predetermined position above the leader. It is preferable to restrict.

  Since this invention is comprised as mentioned above, there exist the following effects.

  By considering not only the vertical relationship between the pressure of the pressure oil supplied to the hydraulic motor and the pressure reference value, but also the time during which such vertical relationship continues, stable and smooth automatic shift control can be performed. In addition, while using only one hydraulic motor, the number of shift stages can be arbitrarily increased as necessary, and stable and smooth automatic shift control is possible.

  In the automatic transmission control according to the present invention, it is possible to arbitrarily set the upper limit value and the lower limit value of the driving torque of the tool, and it is possible to safely and appropriately carry out the construction according to the ground state and construction contents. . In addition, by performing the automatic shift control of the present invention, the pressure and flow rate of the pressure oil supplied to the hydraulic motor can be kept almost constant, and the prime mover of the pressure oil supply source can be operated with maximum efficiency, so that the tool drive Efficiency can be improved.

  Even when the rotation of the tool is constrained and becomes a rotationally constrained state, it is possible to automatically return from the rotationally constrained state to the rotational state. Furthermore, since stable and smooth automatic shift control can be performed with only one hydraulic motor, the manufacturing cost of the ground construction machine can be greatly reduced.

FIG. 1 is a schematic diagram showing the overall configuration of a ground construction machine 1 according to the present invention. FIG. 2 is a schematic diagram showing the configuration of the hydraulic motor 81 and the rotation drive unit 8. FIG. 3 is a graph showing the relationship between the drive torque on the output shaft of the hydraulic motor 81 and the torque index. FIG. 4 is a graph showing the relationship between the displacement of the hydraulic motor 81 and the drive torque on the output shaft. Figure 5 is a diagram showing a pressure reference value P _s and the reference time t _s for the automatic shift control. FIG. 6 is a flowchart showing a processing procedure of automatic shift control. FIG. 7 is a flowchart showing the processing procedure of the torque increase subroutine. FIG. 8 is a flowchart showing the processing procedure of the torque reduction subroutine. FIG. 9 is a flowchart showing the processing procedure of the torque setting subroutine.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of a ground construction machine 1 according to the present invention. The ground construction machine 1 has an endless track ring 3 and is configured to be able to run on its own. The leader 4 is a support for supporting and guiding the tool 11. The leader 4 can move up and down from a vertical state to a horizontal state with respect to the ground, and can turn together with the cab 5. When the ground construction machine 1 is moved or transported, the leader 4 is brought down to a horizontal state and moved while being held in a horizontal state at the upper part of the main body. The leader 4 is supported so as to be able to swing around a fulcrum 9, and the hydraulic cylinder 6 is operated by the operation on the cab 5 so that the leader 4 is raised and lowered.

  A drive head 7 is provided so that the leader 4 can be moved up and down with the leader 4 standing up. A hydraulic motor 81 (see FIG. 2) and a rotary drive unit 8 are fixedly disposed on the drive head 7. Has been. The hydraulic motor 81 and the rotational drive unit 8 are for rotationally driving the tube body 10 having the tool 11 fixed to the distal end side. The tube body 10 is a hollow tubular member, and a ground improver or the like can be injected into the ground through the hollow portion inside. A tool 11 such as an excavating tool or a stirring tool is fixed to the distal end side (downward side) of the tube body 10.

  The drive head 7 can move up and down on the reader 4 by a drive mechanism (not shown). When the drive head 7 is moved, the tube body 10 and the tool 11 are moved by the same amount together with the rotation drive unit 8. For example, a tool provided with a lower-end excavation tool and a stirring tool is used as the tool 11, and the tube body 10 is lowered while being rotationally driven, so that excavation work and ground improvement work by stirring are simultaneously performed. At this time, the ground improvement agent is ejected from the stirring tool and injected into the ground structure, and the ground structure is stirred to improve the ground. The ground improvement agent is cement milk or the like, and is supplied through the hollow portion of the tube body 10.

  The ground construction machine 1 may be attached only with excavation work such as an auger screw to perform excavation work. Thus, when performing ground improvement work or excavation work by the ground construction machine 1, it is necessary to set the drive torque and rotation speed of the tool 11 to appropriate values according to the ground condition (soft, hard, etc.). . For example, it is necessary to increase the driving torque of the tool 11 (reducing the rotational speed) on hard ground, while increasing the rotational speed (reducing the driving torque) on soft ground to perform highly efficient excavation work. it can.

  FIG. 2 is a schematic diagram showing the configuration of the hydraulic motor 81 and the rotation drive unit 8. Here, the rotation drive unit 8 (see FIG. 1) includes a speed reduction mechanism 82, a spindle 83, and a chuck 84, and transmits the rotation output of the hydraulic motor 81 to the tube body 10 and the tool 11 (see FIG. 1). It is. The speed reduction mechanism 82 reduces the rotational output of the hydraulic motor 81 and transmits it to the spindle 83. The spindle 83 is supported rotatably with respect to the drive head 7.

  A chuck 84 is fixed to the spindle 83, and the tube body 10 can be gripped by the chuck 84 or the tube body 10 can be released. If the tube body 10 is gripped by the chuck 84, the tube body 10 is fixed to the spindle 83, and the tube body 10 and the tool 11 can be rotationally driven by the rotation of the spindle 83.

  The hydraulic motor 81 can continuously change the displacement volume. The hydraulic motor 81 preferably has a low rotational speed and high torque rotational output characteristics. As the hydraulic motor 81, for example, an eccentric radial piston motor can be used. In this eccentric radial piston motor, a central eccentric cylindrical cam and an output shaft are rotationally driven by pistons arranged radially with respect to the output shaft. If the eccentric amount of the eccentric cylindrical cam can be adjusted continuously, the displacement of the hydraulic motor can be continuously changed by changing the eccentric amount.

  The drive control unit 85 supplies pressure oil from a hydraulic source to the hydraulic motor 81 to perform rotational drive control of the hydraulic motor 81. The pressure P of the pressure oil supplied to the hydraulic motor 81 is detected by the pressure detector 86, and the detected value is sent to the drive control unit 85. The drive control unit 85 performs automatic shift control, that is, drive torque control of the tool 11 in accordance with the pressure P of the pressure oil supplied to the hydraulic motor 81.

  Further, the drive control unit 85 can receive the signal from the encoder 87 and obtain the rotational speed of the output shaft of the hydraulic motor 81. The encoder 87 outputs a pulse signal corresponding to the rotation angle of the output shaft of the hydraulic motor 81. That is, the encoder 87 can be used as a rotational speed detector of the hydraulic motor 81.

  The drive control unit 85 includes a CPU 851 and a storage unit 852 inside, and the CPU 851 performs various types of information processing. The storage unit 852 stores various data and programs necessary for drive control and information processing. In addition, data resulting from information processing is also stored in the storage unit 852.

  The drive control unit 85 can send an electrical control signal to the hydraulic motor 81 to change and control the displacement of the hydraulic motor 81 to an arbitrary value within a predetermined range. The drive control unit 85 changes the displacement volume of the hydraulic motor 81 to perform change control of the drive torque and rotation speed of the output shaft. Thereby, automatic transmission control of the ground construction machine 1, that is, automatic control for changing and controlling the driving torque of the tool 11 to an appropriate value is performed.

  Next, automatic shift control performed by the drive control unit 85 will be described. In the shift control method for the ground construction machine 1 of the present invention, the hydraulic motor 81 can continuously change the displacement volume. For this reason, also regarding the speed change control method, feedback control in which the displacement volume of the hydraulic motor 81 is continuously changed according to the load torque applied to the tube body 10 is also conceivable. However, in such simple feedback control, the displacement of the hydraulic motor is greatly changed and controlled due to a sudden torque fluctuation due to a change in the ground condition or the like, and the shift control may vibrate and become unstable. In addition, the tool itself may vibrate, and the tool and the ground construction machine may be damaged.

  Therefore, in the shift control method of the ground construction machine 1 of the present invention, the upper limit value and the lower limit value of the drive torque of the hydraulic motor 81 are set, and a plurality of drive torque values are set within a range including the upper limit value and the lower limit value. Thus, automatic shift control is performed using these stepwise drive torque values. That is, in the speed change control method of the present invention, instead of performing continuous change control of drive torque, a plurality of stepwise drive torque values are set for a continuous numerical range of drive torque. Automatic transmission control is performed using stepwise drive torque values.

First, the maximum value T _max and the minimum value T _min of the drive torque of the hydraulic motor 81 are stored in the storage unit 852 inside the drive control unit 85. This is the range of drive torque obtained from the output characteristics of the hydraulic motor 81. The range of the drive torque of the hydraulic motor 81 that can be used practically is a section between the maximum value and the minimum value. That is, the normally usable drive torque value is not less than the minimum value T _{min and not} more than the maximum value T _max . The manufacturer T of the ground construction machine 1 can set the minimum value T _min and the maximum value T _max of the driving torque in advance. Further, the user may be able to set or change the minimum value T _min and the maximum value T _max .

  The driving torque of the hydraulic motor 81 is set to a limit value when the driving head 7 is positioned above the leader 4. Here, the upper part of the reader 4 refers to a position above a predetermined position above the reader 4. When the drive head 7 is in a position above a predetermined position above the leader 4, the drive torque of the hydraulic motor 81 is limited to a limit value or less.

  This limit value is also stored in the storage unit 852 inside the drive control unit 85. When the driving head 7 is positioned above the leader 4, if the driving torque of the hydraulic motor 81 increases, the leader 4 is heavily loaded, and the leader 4 tilts. In the worst case, the ground construction machine 1 falls. There is also a risk. For this reason, when the drive head 7 is in a position above the predetermined position above the leader 4, it is desirable to limit the drive torque of the hydraulic motor 81 to a predetermined limit value or less.

  This limit value is a value at which construction work can be performed safely even when the drive head 7 is above the leader 4. The limit value is a default value set by the manufacturer, but the user can change the limit value. This limit value corresponds to the second upper limit value in the claims. That is, the limit value and the second upper limit value are the same.

  The drive control unit 85 constantly monitors the position of the drive head 7. When the drive head 7 is positioned above the reader 4, the drive torque of the hydraulic motor 81 is limited to the limit value (second upper limit value) or less. The Even if the driving torque of the hydraulic motor 81 is changed by manual operation or automatic shift control, the driving torque increases only up to this limit value. When the drive head 7 is not in the upper position of the leader 4, the drive torque of the hydraulic motor 81 can be changed to a value exceeding this limit value.

Further, the upper limit value and the lower limit value of the drive torque when the automatic transmission control or the drive torque is manually set are stored in the storage unit 852 inside the drive control unit 85. The drive torque value set automatically or manually is in a range between the lower limit value and the upper limit value (including torque values at both ends). The lower limit value and the upper limit value of the driving torque are set by the user based on the ground condition and experience at the enforcement position. Naturally, the lower limit value and the upper limit value are set to be not less than the minimum value T _{min and not} more than the maximum value T _max of the drive torque.

When the lower limit value and upper limit value of the drive torque are set, the drive control unit 85 automatically obtains eleven levels of drive torque values by dividing the range between the lower limit value and the upper limit value into 10 equal parts. In practice, 11% percentage display of 0%, 10%, 20%, 30%, 40%,..., 100% is used, where the lower limit value of the drive torque is displayed as 0% and the upper limit value is displayed as 100%. . This percentage display is called a torque index. At this time, assuming that the torque value indicated by the torque index x% is T (x), the torque value T (x) is obtained by the following equation 1 with the lower limit value T _L and the upper limit value T _U.

_{T (x) = T L +} (T U -T L) · x / 100 ... formula 1
In the automatic shift control, an appropriate value of any one of the eleven stages of drive torque values from 0% to 100% is automatically assigned according to the ground condition. The drive torque value of the hydraulic motor 81 is controlled so as to automatically transition to any one of 11 stages of drive torque values according to the ground condition. A specific procedure of automatic shift control will be described in detail later.

Note that the upper limit value T _U is a first upper limit value T _U1 that is a normal upper limit value, and a limit value of the drive torque of the hydraulic motor 81 when the drive head 7 is positioned above the leader 4. A second upper limit value T _U2 is stored. The second upper limit value T _U2 is normally set to a value smaller than the first upper limit value T _U1 .

When the driving head 7 is from the normal position i.e. a predetermined position of the leader 4 top a position below, it is set as the upper limit value T _U is the value of the first upper limit value T _U1, is required driving torque value of 11 steps described above. When the driving head 7 is positioned at an upper portion of the leader 4, it is set as the upper limit value T _U is the value of the second upper limit value T _U2, is required driving torque value of 11 steps described above.

FIG. 3 is a graph showing the relationship between the drive torque on the output shaft of the hydraulic motor 81 and the torque index. The horizontal axis of the graph indicates the torque index, and the vertical axis indicates the drive torque. As shown in the graph, the lower limit value T _L and the upper limit value T _U of the drive torque are set between the minimum value T _min and the maximum value T _max of the drive torque.

Then, the torque index corresponding to the lower limit value T _L is set to 0%, and the torque index corresponding to the upper limit value T _U is set to 100%. Then, 11 ranges of torque indices of 0%, 10%, 20%, 30%, 40%,..., 100% are set by dividing the range above the lower limit and below the upper limit into 10 equal parts. The operator of the ground construction machine 1 performs manual drive torque adjustment and automatic torque control (automatic shift control) based on this torque index. Note that the minimum value T _min and the maximum value T _{max of} the drive torque, the lower limit value T _L and the upper limit value T _U , the torque index, and the like are stored in the storage unit 852 inside the drive control unit 85.

  FIG. 4 is a graph showing the relationship between the displacement of the hydraulic motor 81 and the drive torque on the output shaft. The hydraulic motor 81 can continuously change the displacement, and the displacement is changed by a control signal from the drive control unit 85. When the pressure and flow rate of the pressure oil supplied to the hydraulic motor 81 are substantially constant, the displacement volume and driving torque of the hydraulic motor 81 are in a substantially linear relationship as shown in the figure. If there is no leakage or loss of the hydraulic motor 81, the displacement volume and the drive torque are proportional.

The minimum value T _min and the maximum value T _max of the drive torque in the drive characteristics of the hydraulic motor 81 are determined by the minimum value Q _min and the maximum value Q _max of the displacement volume. The minimum value Q _min of the displacement volume corresponds to the minimum value T _min of the driving torque, and the maximum value Q _max of the displacement volume corresponds to the maximum value T _max of the driving torque. By continuously changing the displacement volume from the minimum value Q _min to the maximum value Q _max , the driving torque also changes continuously from the minimum value T _min to the maximum value T _max .

  In order to change the drive torque of the hydraulic motor 81 to a desired value, the displacement volume corresponding to the drive torque is obtained from the relationship shown in FIG. 4, and the displacement volume of the hydraulic motor 81 is changed to the obtained value. The relationship between the drive torque and displacement as shown in FIG. 4 is stored in the storage means 852 in the drive control unit 85 in the form of a calculation formula or numerical table.

  When the pressure and flow rate of the pressure oil supplied to the hydraulic motor 81 are maintained substantially constant, the drive torque of the output shaft of the hydraulic motor 81 is proportional to the displacement volume. The rotation speed of the output shaft is inversely proportional to the drive torque. That is, even if the pressure oil pressure and flow rate are maintained substantially constant, the drive torque can be changed to an appropriate value by changing the displacement of the hydraulic motor.

  As a supply source of the pressure oil supplied to the hydraulic motor 81, a pump driven by a prime mover such as an internal combustion engine is used. In general, it is desirable to use the prime mover in the vicinity of the most efficient rated output. At this time, the supply efficiency of pressure oil is also maximized. By performing the automatic torque control (automatic shift control) of the present invention, the pressure and flow rate of the pressure oil supplied to the hydraulic motor 81 can be kept substantially constant, and the prime mover of the pressure oil supply source can be operated with maximum efficiency. Therefore, the efficiency of tool driving can be improved.

  Next, automatic return control of tool rotation in the present invention will be described. In the ground construction machine 1, the load by the ground is too large, and the rotation of the tool 11 may be restricted and stopped. In this case, the rotation of the output shaft of the hydraulic motor 81 is also restrained and stopped. At this time, even if the driving torque of the hydraulic motor 81 is increased and the driving of the tool 11 is resumed, the displacement of the hydraulic motor 81 may not change. The ground construction machine 1 of the present invention has a function of smoothly releasing the restraint state of the hydraulic motor 81 and returning to the rotational drive state in such a case.

  That is, when the rotation of the output shaft of the hydraulic motor 81 is restricted, the supply of pressure oil to the hydraulic motor 81 is automatically stopped for a certain period of time. Then, control is performed to increase the driving torque by one step by changing the displacement volume of the hydraulic motor 81. Thereafter, the supply of pressure oil to the hydraulic motor 81 is resumed, and the hydraulic motor 81 is returned to the rotating state. Thus, the displacement volume can be reliably changed by changing the displacement volume while the supply of the pressure oil is stopped.

  This is considered to be because by stopping the supply of the pressure oil, an excessive force acting on each part of the hydraulic motor 81 at the time of restraint is removed, and the displacement volume changing mechanism operates smoothly. Thus, by performing automatic return control of the hydraulic motor 81 from the rotationally restricted state to the rotational state, the operator of the ground construction machine 1 automatically performs normal rotational driving from the rotationally restricted state without performing complicated operations. It can be returned to the state.

  Next, the automatic shift control and the automatic return control as described above in the present invention will be described more specifically. The drive control unit 85 performs automatic shift control according to the pressure P of the pressure oil supplied to the hydraulic motor 81. The drive control unit 85 stores a plurality of pressure reference values for performing automatic shift control in comparison with the pressure P. That is, the pressure reference value (upper reference value) used for determining whether to increase the torque value and the pressure reference value (lower reference value) used for determining whether to decrease the torque value are respectively determined. It is stored in correspondence with the torque state. Further, a reference time serving as a reference for the time during which the torque value transition condition continues is stored in association with each torque state.

  The drive control unit 85 compares the pressure P with the pressure reference value (upper reference value), and increases the drive torque by one step when the state where the pressure P is equal to or higher than the upper reference value continues for the reference time or longer. Further, the drive control unit 85 compares the pressure P with the pressure reference value (lower reference value), and when the state where the pressure P is lower than the lower reference value continues for the reference time or longer, the drive control unit 85 decreases the drive torque by one step. Let When the pressure P is larger than the lower reference value and smaller than the upper reference value, the driving torque is maintained as it is.

FIG. 5 is a diagram illustrating an example of set values of the pressure reference value P _s and the reference time t _s for automatic shift control. Set value of the pressure reference value P _s and the reference time t _s is stored in the internal storage unit 852 the drive control unit 85. In the automatic transmission control, the driving torque of the hydraulic motor 81 is automatically selected from torque values corresponding to the 11-step torque index and set to an appropriate torque value. Moreover, even if the ground state changes during construction, the driving torque is automatically changed to an appropriate driving torque according to the ground state.

  Here, an index number n is defined for each of 11 stages of torque indices 0% to 100% of the drive torque. That is, the index number: 0 corresponds to the torque index 0%, the index number: 1 corresponds to the torque index 10%, and the index number: 2 corresponds to the torque index 20%. Similarly, the index numbers: 3 to 10 are made to correspond to the torque indexes 30% to 100%, respectively. The torque index 100% corresponds to the index number: 10.

  Here, the operation of increasing the driving torque by one step is the same as shifting from the driving torque corresponding to the index number n to the driving torque corresponding to the index number n + 1. Further, the operation of reducing the driving torque by one step is the same as shifting from the driving torque corresponding to the index number n to the driving torque corresponding to the index number n-1.

The pressure reference value P _s and the reference time t _s are set for each drive torque transition operation. When the current drive torque state is a torque value corresponding to the index number n, the pressure reference value (upper reference value) used to determine whether to increase the torque value is represented as P _s (n, n + 1). . The reference time for the pressure reference value is expressed as t _s (n, n + 1). The pressure reference value (lower reference value) used for determining whether to decrease the torque value is represented as P _s (n, n−1). Further, the reference time for the pressure reference value is expressed as _ts (n, n-1).

Here, the pressure reference value P _s (n, n + 1) and the reference time t _s (n, n + 1) are set for n = 0 to 9, and the pressure reference value P _s (n, n−1) and the reference time are set. t _s (n, n−1) is set for n = 1 to 10.

The pressure reference value P _s and the reference time t _s are set for each of 11 steps of driving torque values with respect to the first upper limit value T _U1, which is the upper limit value in the normal state. It is also set for each of 11 steps of driving torque with respect to the second upper limit value T _U2, which is the upper limit value when the head 7 is positioned above the leader 4. That is, two types of tables as shown in FIG. 5 are stored, and are used properly according to the position of the drive head 7. Note that the pressure reference value and reference time table as shown in FIG. 5 is stored in the storage means 852 in the drive control unit 85.

  Here, the control in the case where the drive head 7 is positioned above the reader 4 is performed by setting the 11 stages of drive torque with the upper limit value of the drive torque as the second upper limit value. It is not limited to simple control. When the driving head is positioned above the leader, the driving torque may simply be set not to exceed the limit value.

  Next, a specific control procedure for automatic shift control and automatic return control will be described based on the flowcharts of FIGS. 6 to 9 show the contents of the program executed by the drive control unit 85. FIG. 6 is a flowchart showing a processing procedure of automatic shift control. When an operation for starting the rotational drive of the tool 11 is performed in a state where the shift control mode of the ground construction machine 1 is set to the automatic shift mode, the procedure of the flowchart of FIG. 6 is started.

  In step 101, the rotational drive of the hydraulic motor 81 is started. Thus, when the construction of the ground is started, automatic shift control is executed by repeating the processing from step 102 to step 106. That is, the drive torque of the hydraulic motor 81 is changed to an appropriate value according to the ground condition and the load on the tool 11.

  In step 101, an initial torque for automatic shift control is set. The initial torque is an initial value of the drive torque at the start of automatic shift control. The operator can set an arbitrary initial value from a torque index of 0% to 100%. If the operator has not set an initial value, a torque value corresponding to a torque index of 50% is set as a default value. Then, the value of the index number corresponding to the initial value is substituted into the variable n indicating the index number of the current driving torque. For example, when the initial value is a torque index of 50%, 5 is substituted into a variable n representing the current number of driving torque indices.

In step 102, the position of the driving head 7 on the reader 4 is detected. Next, in step 103, a drive torque and a torque index are set, and a pressure reference value and a reference time are set. In these settings, either the first upper limit value T _U1 or the second upper limit value T _U2 is set as the upper limit value T _U according to the position of the drive head 7 on the reader 4, thereby corresponding to each torque index. Eleven levels of driving torque values are obtained. Further, the pressure reference value and the reference time corresponding to the position of the drive head 7 are set to be used.

  In step 103, the number of indices is corrected when the position of the drive head 7 changes from the normal position to the upper position, or when the position changes from the upper position to the normal position. This is because the value of the drive torque corresponding to the number of indexes differs between the case where the position of the drive head 7 is the normal position and the case where the position is the upper position. When the position of the drive head 7 is changed between the normal position and the upper position, first, the drive torque corresponding to the number of indices before the position change is obtained, and the drive torque closest to the drive torque is changed to 11 after the position change. Select from among the drive torques in stages. Then, the index number corresponding to the selected drive torque is substituted into the variable n. The variable n represents the current drive torque index number.

  In the next procedure 104, a process for calling a torque increase subroutine is performed. The torque increase subroutine executes the processing procedure shown in FIG. 7 and performs processing for increasing the drive torque according to each condition in automatic shift control. This torque increase subroutine will be described in detail later.

  When returning to the calling source from the torque increase subroutine, the process proceeds to step 105. In step 105, a process for calling a torque reduction subroutine is performed. The torque reduction subroutine executes the processing procedure shown in FIG. 8, and performs processing to reduce the drive torque according to each condition in automatic shift control. This torque reduction subroutine will be described in detail later. When returning to the calling source from the torque reduction subroutine, the process proceeds to step 106.

  In step 106, it is determined whether or not to continue automatic shift control. When the speed change control mode of the ground construction machine 1 is changed to the manual speed change mode, or when the ground work is finished and the rotation drive of the tool 11 is stopped, the procedure proceeds from the step 106 to “No” and the automatic speed change control is finished. . If there is no such operation for ending the automatic transmission control, the process proceeds from step 106 to “Yes”, returns to step 102, and repeats the processes of steps 102 to 106.

  FIG. 7 is a flowchart showing the processing procedure of the torque increase subroutine. The torque increase subroutine is a process for increasing the drive torque of the hydraulic motor 81 according to each condition in the automatic shift control. When the torque increase subroutine is called, first, in step 201, it is determined whether or not the value of the currently set driving torque index number n is 10. When the value of the index number n is 10, the index number n = 10 corresponds to the upper limit value of the drive torque, and the drive torque cannot be increased any more. Therefore, the process of the torque increase subroutine is terminated and the process returns to the calling source. .

If the value of the index number n is not 10 (0 to 9), the process proceeds from the procedure 201 to the procedure 202. In step 202, the timer built in the drive control unit 85 is reset and time measurement is started. By this timer, the time during which the state where the pressure P of the pressure oil supplied to the hydraulic motor 81 is equal to or higher than the pressure reference value P _s (n, n + 1) is measured.

Next, in step 203, the detected value of the pressure P of the pressure oil supplied to the hydraulic motor 81 is compared with the pressure reference value P _s (n, n + 1). The pressure reference value P _s (n, n + 1) corresponding to the current driving torque index number n is selected from the table shown in FIG. If the pressure P is greater than or equal to the pressure reference value P _s (n, n + 1), the process proceeds to the next step 204. If not, the process of the torque increase subroutine is terminated and the process returns to the calling source.

In the next procedure 204, the time t being measured by the timer is compared with the reference time t _s (n, n + 1). The reference time t _s (n, n + 1) corresponding to the current driving torque index number n is selected from the table shown in FIG. If the time t is equal to or greater than the reference time t _s (n, n + 1), the process proceeds to step 205. If not, the process returns to step 203, and steps 203 to 204 are repeated.

Eventually, in step 203 and step 204, it is determined whether or not the state where the pressure P is equal to or higher than the pressure reference value P _s (n, n + 1) continues for the reference time t _s (n, n + 1). If it continues for the reference time t _s (n, n + 1) or longer, the process proceeds to step 205. If not continued, the process of the torque increase subroutine is terminated and the process returns to the calling source. That is, if the state where the pressure P is equal to or higher than the pressure reference value P _s (n, n + 1) does not continue for the reference time t _s (n, n + 1), the driving torque is not increased.

  In step 205, a value (n + 1) is substituted into a variable m representing the number of indices. Since the driving torque of the hydraulic motor 81 is set by the value of the variable m, this substitution indicates that the driving torque is increased by one step. In the next step 206, a process for calling a torque setting subroutine is performed. The torque setting subroutine executes the processing procedure shown in FIG. 9 and performs processing for setting the driving torque of the hydraulic motor 81 according to the value of the variable m. This torque setting subroutine will be described in detail later. When returning to the calling source from the torque setting subroutine, the processing of the torque increasing subroutine is terminated and the processing returns to the calling source.

  FIG. 8 is a flowchart showing the processing procedure of the torque reduction subroutine. The torque reduction subroutine performs processing for reducing the drive torque of the hydraulic motor 81 according to each condition in the automatic shift control. When the torque reduction subroutine is called, first, in step 301, it is determined whether or not the value of the currently set driving torque index number n is zero. When the value of the index number n is 0, the index number n = 0 corresponds to the lower limit value of the drive torque, and the drive torque cannot be reduced any further. Therefore, the process of the torque reduction subroutine is terminated and the process returns to the calling source.

When the value of the index number n is not 0 (in the case of 1 to 10), the process proceeds from the procedure 301 to the procedure 302. In step 302, a timer built in the drive control unit 85 is reset and time measurement is started. By this timer, the time during which the state where the pressure P of the pressure oil supplied to the hydraulic motor 81 is equal to or lower than the pressure reference value P _s (n, n−1) is measured.

Next, in step 303, the detected value of the pressure P of the pressure oil supplied to the hydraulic motor 81 is compared with the pressure reference value P _s (n, n−1). As the pressure reference value P _s (n, n−1), a pressure corresponding to the current driving torque index number n is selected from the table shown in FIG. If the pressure P is equal to or less than the pressure reference value P _s (n, n−1), the process proceeds to the next step 304. If not, the process of the torque reduction subroutine is terminated and the process returns to the calling source.

In the next procedure 304, the time t being measured by the timer is compared with the reference time t _s (n, n−1). As this reference time t _s (n, n−1), the one corresponding to the current driving torque index number n is selected from the table shown in FIG. If the time t is equal to or greater than the reference time t _s (n, n−1), the process proceeds to step 305. Otherwise, the process returns to step 303, and steps 303 to 304 are repeated.

Eventually, in steps 303 and 304, it is determined whether or not the state where the pressure P is equal to or lower than the pressure reference value P _s (n, n−1) continues for the reference time t _s (n, n−1). The If it continues for the reference time t _s (n, n−1) or longer, the process proceeds to step 305, and if not continued, the process of the torque reduction subroutine is terminated and the process returns to the calling source. That is, unless the state where the pressure P is equal to or lower than the pressure reference value P _s (n, n−1) continues for the reference time t _s (n, n−1) or longer, the driving torque is not reduced.

  In step 305, a value (n-1) is substituted into a variable m representing the number of indices. Since the driving torque of the hydraulic motor 81 is set by the value of the variable m, this substitution represents that the driving torque is reduced by one step. In the next procedure 306, a process for calling a torque setting subroutine is performed. The torque setting subroutine executes the processing procedure shown in FIG. 9 and performs processing for setting the driving torque of the hydraulic motor 81 according to the value of the variable m. When returning from the torque setting subroutine to the calling source, the processing of the torque reduction subroutine is terminated and the processing returns to the calling source.

  FIG. 9 is a flowchart showing the processing procedure of the torque setting subroutine. This torque setting subroutine performs processing for setting the drive torque of the hydraulic motor 81 based on the value of the variable m representing the number of indices. The torque setting subroutine also incorporates a procedure for automatic return control from the rotation restraint state to the rotation state. This torque setting subroutine is used not only for automatic shift control in the automatic shift mode but also for manually setting the drive torque value in the manual shift mode.

  When the torque setting subroutine is called, it is first determined in step 401 whether or not the automatic return control from the rotation restraint state to the rotation state is turned on. If the automatic return control is on, the process proceeds to step 402. If the automatic return control is off, the process proceeds to step 410. That is, when the automatic return control is turned off on the operation panel, the automatic return control is not performed, and the drive torque of the hydraulic motor 81 is simply set according to the value of the variable m.

  In step 410, in order to set the driving torque corresponding to the value of the variable m representing the number of indices, first, the displacement corresponding to the driving torque is obtained from the relationship of FIG. Then, the displacement volume of the hydraulic motor 81 is set to the obtained volume. In addition, the displacement volume of the hydraulic motor 81 is set, and at the same time, the value of the variable m is substituted for the variable n indicating the current index number of the driving torque. Thereby, the index number of the drive torque after the change is set to the variable n. After step 410, the process of the torque setting subroutine is terminated and the process returns to the calling source.

  In step 401, if the automatic return control is on, the process proceeds to step 402, and it is determined whether or not the value of the variable m is larger than the value of the variable n. If the value of the variable m is larger, it means that the drive torque is increased, and the procedure proceeds to step 403, where the drive torque is set with automatic return control. Otherwise, the drive torque is not increased, so the procedure proceeds to step 410, and the automatic return control is not performed, and the drive torque of the hydraulic motor 81 is simply set according to the value of the variable m. That is, the automatic return control is performed only when an instruction to increase the drive torque is given.

In step 403, a timer built in the drive control unit 85 is reset and time measurement is started. By this timer, the rotation speed R of the output shaft of the hydraulic motor 81 is equal to or less than a predetermined constraint reference speed R _r , and the pressure P of the pressure oil supplied to the hydraulic motor 81 is equal to or greater than the constraint pressure reference value _Pr. Measure the time that the condition lasts.

Here, the restriction reference speed R _r is a reference value of the rotation speed of the output shaft of the hydraulic motor 81 for determining that the tool 11 is in the rotation restricted state. The restraint pressure reference value _Pr is a reference value of the pressure of the pressure oil supplied to the hydraulic motor 81 for determining that the tool 11 is in the rotation restraint state. That is, the rotational speed R of the output shaft of the hydraulic motor 81 is less constrained reference speed R _r, and the pressure P of the pressure oil supplied to the hydraulic motor 81 is above restraining pressure reference value P _r state is given When the restriction reference time _{tr is} continued, it is determined that the tool 11 is in the rotation restricted state.

First, in step 404, it is determined whether or not the rotational speed R of the output shaft of the hydraulic motor 81 is equal to or lower than the constraint reference speed _Rr . If less constrained reference speed R _r go to Step 405, set according to the value of the driving torque variable m simply the hydraulic motor 81 without automatic return control proceeds to step 410 otherwise. Information on the rotational speed R of the output shaft of the hydraulic motor 81 is obtained from a detection signal from the encoder 87. The actual value of the constraint reference speed R _r is about 1 [rotation / min]. The value of the restriction reference speed R _r can also be set by the user.

Next, in step 405, it is determined whether or not the pressure P of the pressure oil supplied to the hydraulic motor 81 is greater than or equal to the restraint pressure reference value _Pr . If restraining pressure reference value P _r or proceed to step 406, set according to the value of the driving torque variable m simply the hydraulic motor 81 without automatic return control proceeds to step 410 otherwise. A value close to the maximum value of the pressure oil supplied to the hydraulic motor 81 is set as the value of the restraint pressure reference value _Pr . When rotation is constrained, the maximum value of the pressure oil supply pressure is detected.

Next, in step 406, the time t during the measurement by the timer is compared with the restraining reference time t _r. The actual value of the constraint reference time t _r is about 1 second. The value of this restraint reference time t _r is also user-configurable. Time t is go to step 407 if the more restraint the reference time t _r, return to step 404 if not, repeat the procedure 406 from step 404.

Eventually, in steps 404 to 406, the rotational speed R of the output shaft of the hydraulic motor 81 is equal to or lower than the constraint reference speed R _r , and the pressure P of the pressure oil supplied to the hydraulic motor 81 is equal to the constraint pressure reference value P. _It is determined whether or not the state of _r or more continues for the constraint reference time _tr or more. Proceed to Step 407 if continuous restraint reference time t _r or more, setting the drive torque of the automatic return control is simply the hydraulic motor 81 without the process proceeds to Step 410 to be continued according to the value of the variable m. In other words, the automatic return control is not performed unless the rotation constraint state continues for a predetermined constraint reference time _tr or more.

  In step 407, the supply of pressure oil to the hydraulic motor 81 is stopped, and the rotational drive of the hydraulic motor 81 is turned off. This rotation drive stop time is a predetermined time that is set in advance, and is specifically about 0.1 seconds. The value of this stop time can also be set by the user. After turning off the rotational drive of the hydraulic motor 81 in step 407, the process immediately proceeds to step 408 to set the drive torque. When a predetermined stop time has elapsed, the rotational drive of the hydraulic motor 81 is turned on again in step 409. .

  In step 408, in order to set the driving torque corresponding to the value of the variable m representing the number of indices, the displacement volume corresponding to the driving torque is obtained, and the displacement volume of the hydraulic motor 81 is set to the obtained value. In addition, the displacement volume of the hydraulic motor 81 is set, and at the same time, the value of the variable m is substituted for the variable n indicating the current index number of the driving torque. Thereby, the index number of the drive torque after the change is set to the variable n.

  In the next procedure 409, after a predetermined stop time has elapsed, the rotational drive of the hydraulic motor 81 is turned on again. After step 409, the process of the torque setting subroutine is terminated and the process returns to the calling source. In the above torque setting subroutine, the drive torque of the hydraulic motor 81 is set by the value of the variable m representing the number of indices, and if the automatic return control is on, the automatic return control from the rotation restraint state to the rotation state is performed. With the automatic return control, the operator can automatically return from the rotationally restricted state to the rotational state without performing a particularly complicated operation.

  By performing the automatic shift control according to the processing procedures as shown in FIGS. 6 to 9, the stability of the automatic shift control can be greatly improved. In other words, stable and smooth automatic shift control can be performed by considering not only the vertical relationship between the pressure of the pressure oil supplied to the hydraulic motor and the pressure reference value, but also the time during which such vertical relationship continues. ing. In addition, while using only one hydraulic motor, the number of shift stages can be arbitrarily increased as necessary, and this also enables stable and smooth automatic shift control.

  Moreover, it is possible to arbitrarily set the upper limit value and the lower limit value of the driving torque of the tool, and it is possible to perform the work safely and appropriately according to the condition of the ground and the construction content. In addition, by performing the automatic shift control as described above, the pressure and flow rate of the pressure oil supplied to the hydraulic motor can be kept almost constant, and the prime mover of the pressure oil supply source can be operated with maximum efficiency. Driving efficiency can be improved.

  Even when the rotation of the tool is constrained and becomes a rotationally constrained state, it is possible to automatically return to the rotational state from the rotationally constrained state. Furthermore, since stable and smooth automatic shift control can be performed with only one hydraulic motor, the manufacturing cost of the ground construction machine can be greatly reduced.

  As described above, according to the present invention, stable and smooth automatic shift control is possible, and by arbitrarily setting the upper limit value and the lower limit value of the driving torque of the tool, the state of the ground and the construction contents Depending on the situation, construction can be carried out safely and appropriately. Further, even when the rotation of the tool is constrained and becomes a rotationally constrained state, it is possible to automatically return from the rotationally constrained state to the rotational state.

  In the description of the above embodiment, the range between the lower limit value and the upper limit value of the drive torque in the automatic shift control is equally divided into 10 to set the 11 stages of drive torque values. The drive torque value may be set not only in the steps but also in any number of steps. For example, drive torques such as 21 steps and 41 steps can be set. Also, the number of stages of driving torque can be made smaller than 11 stages.

  According to the present invention, it is possible to provide a stable and smooth automatic transmission control in a ground construction machine, and it is possible to provide a ground construction machine that executes a stable and smooth automatic transmission control. Furthermore, it is possible to automatically return to the rotation state from the rotation restrained state of the tool, and to provide a low-cost ground construction machine.

DESCRIPTION OF SYMBOLS 1 Ground construction machine 3 Track belt 4 Leader 5 Driver's cab 6 Hydraulic cylinder 7 Drive head 8 Rotation drive part 9 Support point 10 Tube body 11 Tool 81 Hydraulic motor 82 Deceleration mechanism 83 Spindle 84 Chuck 85 Drive control part 86 Pressure detector 87 Encoder 851 CPU
852 storage means

Claims (7)

A tool (11) for construction on the ground by rotational drive;
A hydraulic motor (81) capable of continuously changing the displacement volume and rotationally driving the tool (11);
A pressure detector (86) for detecting the pressure of the fluid supplied to the hydraulic motor (81) ;
A shift control method in a ground construction machine comprising a rotation speed detector (87) for detecting the rotation speed of the hydraulic motor (81) ,
A procedure for setting an upper limit value and a lower limit value of the drive torque actually used for rotational driving of the tool (11) within a range of drive torque that can be generated by the hydraulic motor (81);
A procedure for setting a plurality of driving torques including the lower limit value and the upper limit value in a range not less than the lower limit value and not more than the upper limit value;
A procedure for obtaining a plurality of displacement volumes of the hydraulic motor (81) respectively corresponding to the plurality of set driving torques;
A procedure for setting a reference value of the pressure for shifting from a displacement volume other than the lower limit volume corresponding to the lower limit value to a displacement volume one step smaller as a lower reference value for each displacement volume;
A procedure for setting the reference value of the pressure for shifting from the displacement volume other than the upper limit volume corresponding to the upper limit value to the displacement volume one step larger as the upper reference value for each displacement volume;
A procedure for setting, for each transition, a reference time for transitioning from the displacement volume to the adjacent displacement volume;
A procedure for shifting to a one-step smaller displacement when the hydraulic motor (81) is in a predetermined displacement other than the lower limit and the pressure is below a lower reference value for a reference time or longer. When,
A procedure for shifting to a one-step larger displacement volume when the hydraulic motor (81) is in a predetermined displacement volume other than the upper limit and the pressure is equal to or higher than the upper reference value for a reference time or longer. It has a door,
When the displacement volume of the hydraulic motor (81) is increased by one step in the procedure for shifting to the one-step larger displacement volume, the rotational speed of the output shaft of the hydraulic motor (81) is equal to or lower than a predetermined constraint reference speed. When the state where the pressure is equal to or greater than the predetermined constraint pressure reference value continues for a predetermined constraint reference time or more, it is determined that the rotation of the tool (11) is constrained, and the hydraulic motor ( 81) A shift control method in a ground construction machine that executes a procedure of increasing the displacement volume after stopping the supply of fluid to 81) and then starting the supply of fluid to the hydraulic motor (81) . A shift control method in the ground construction machine according to claim 1 ,
The procedure for setting the plurality of drive torques is a shift control method for a ground construction machine, wherein 11 stages of drive torque including the lower limit value and the upper limit value are set. A shift control method for a ground construction machine according to any one of claims 1 and 2 ,
The ground construction machine is movably provided along a rotation drive unit (82 to 84) for transmitting the rotation output of the hydraulic motor (81) to the tool (11) and a guide leader (4). And a drive head (7) in which the hydraulic motor (81) and the rotary drive units (82 to 84) are arranged,
When the drive head (7) is positioned above the predetermined position above the leader (4), the shift in the ground construction machine is to limit the change range of the drive torque to a second upper limit value which is smaller than the upper limit value. Control method. A shift control method in the ground construction machine according to claim 3 ,
When the driving head (7) is positioned above a predetermined position above the reader (4),
A procedure for setting the second upper limit value smaller than the upper limit value;
A procedure for setting a plurality of driving torque values including the lower limit value and the second upper limit value in a range not less than the lower limit value and not more than the second upper limit value;
A procedure for obtaining a plurality of displacement volumes of the hydraulic motor (81) respectively corresponding to the plurality of set driving torque values;
A procedure for setting a reference value of the pressure for shifting from a displacement volume other than the lower limit volume corresponding to the lower limit value to a displacement volume one step smaller as a lower reference value for each displacement volume;
A procedure for setting the reference value of the pressure for shifting from the displacement volume other than the upper limit volume corresponding to the second upper limit value to the displacement volume one step larger as the upper reference value for each displacement volume;
A procedure for setting, for each transition, a reference time for transitioning from the displacement volume to the adjacent displacement volume;
A procedure for shifting to a one-step smaller displacement when the hydraulic motor (81) is in a predetermined displacement other than the lower limit and the pressure is below a lower reference value for a reference time or longer. When,
When the hydraulic motor (81) is in a predetermined displacement volume other than the second upper limit value and the pressure is continuously above the upper reference value for a reference time or longer, the displacement shifts to one step larger. A shift control method in a ground construction machine having a procedure to perform. A tool (11) for construction on the ground by rotational drive;
A hydraulic motor (81) capable of continuously changing the displacement volume and rotationally driving the tool (11);
A rotation drive unit (82 to 84) for transmitting the rotation output of the hydraulic motor (81) to the tool (11);
A drive head (7) provided so as to be movable along the guide leader (4), wherein the hydraulic motor (81) and the rotation drive units (82 to 84) are disposed;
A pressure detector (86) for detecting the pressure of the fluid supplied to the hydraulic motor (81);
A rotational speed detector (87) for detecting the rotational speed of the hydraulic motor (81);
A drive control unit (85) for controlling the displacement of the hydraulic motor (81) to control the hydraulic motor (81) to generate an appropriate driving torque;
The drive control unit (85) includes storage means (852) for storing information,
The storage means (852)
Within the range of drive torque that can be generated by the hydraulic motor (81), the upper limit value and lower limit value of the drive torque actually used for rotational driving of the tool (11) are stored, and the upper limit value and the upper limit value are stored. Storing a plurality of driving torques including the lower limit value and the upper limit value within a range below the value;
Storing a plurality of displacement volumes of the hydraulic motor (81) respectively corresponding to the plurality of set driving torques;
The reference value of the pressure for shifting from the displacement volume other than the lower limit value to the displacement volume smaller by one step is stored as a lower reference value for each displacement volume, and 1 from the displacement volume other than the upper limit value. Storing the reference value of the pressure for transitioning to a larger displacement volume as an upper reference value for each displacement volume;
A reference time for transitioning from the displacement volume to the adjacent displacement volume is stored for each transition;
Furthermore, the drive control unit (85)
A procedure for shifting to a one-step smaller displacement when the hydraulic motor (81) is in a predetermined displacement other than the lower limit and the pressure is below a lower reference value for a reference time or longer. When,
A procedure for shifting to a one-step larger displacement volume when the hydraulic motor (81) is in a predetermined displacement volume other than the upper limit and the pressure is equal to or higher than the upper reference value for a reference time or longer. run the door,
When the displacement volume of the hydraulic motor (81) is increased by one step, the rotational speed of the output shaft of the hydraulic motor (81) is not more than a predetermined constraint reference speed and the pressure is not less than a predetermined constraint pressure reference value. When a certain state continues for a predetermined restriction reference time or more, it is determined that the rotation of the tool (11) is restricted, and the supply of fluid to the hydraulic motor (81) is stopped before A ground construction machine that increases a displacement volume and then executes a procedure for starting supply of fluid to the hydraulic motor (81) . The ground construction machine according to claim 5 ,
The ground construction machine in which the plurality of drive torques including the lower limit value and the upper limit value are eleven stages of drive torque. The ground construction machine according to any one of claims 5 and 6 ,
When the drive head (7) is positioned above a predetermined position above the leader (4), the drive control unit (85) sets the change range of the drive torque value to a second upper limit value that is less than the upper limit value. The ground construction machine that is to be restricted.

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