JP2008115923A - Control device of working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently perform various works by a telescopic handler. <P>SOLUTION: This control device has a variable displacement type working hydraulic pump 22, a detecting means 33 detecting fork work and bucket work, capacity changing means 22a and 27 each changing pump capacity of the hydraulic pump 21, and a control means 30 controlling the capacity changing means 22a and 27 so that the pump capacity becomes smaller than that when the fork is detected work when the bucket work is detected by the detecting means 33. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for a work machine such as a telescopic handler.

  A wheel-type work machine such as a telescopic handler can be attached with various work attachments at the tip of the telescopic boom, and can perform various work according to the type of work attachment. For example, when a fork is attached to the tip of the telescopic boom, the loading / unloading work of the load placed on the pallet can be performed, and when the bucket is attached, excavation work can be performed. As a prior art document relating to this type of telescopic handler, there is one described in Patent Document 1 below.

JP 2005-54414 A

  By the way, in order to efficiently perform the loading and unloading work, it is preferable to increase the amount of hydraulic oil supplied from the working hydraulic pump to the boom telescopic cylinder via the control valve and quickly perform the boom telescopic operation. . In this case, if the hydraulic pump discharge capacity is set so that the pump discharge amount increases in accordance with the loading / unloading work, no pressure oil supply to the boom expansion / contraction cylinder is required during excavation work. There is a problem in terms of efficiency.

A control device for a work machine according to the present invention includes a variable displacement working hydraulic pump and a first hydraulic oil pump driven by pressure oil from a hydraulic pump in a stop work mode performed in a stopped state and a travel work mode performed in a travel state. 1 hydraulic actuator, a second hydraulic actuator driven by pressure oil from the hydraulic pump only in the stop operation mode, detection means for detecting the operation mode, capacity changing means for changing the pump capacity of the hydraulic pump, Control means for controlling the capacity changing means so that the pump capacity becomes smaller when the traveling work mode is detected by the detecting means than when the stop work mode is detected.
It has a slow speed command means for commanding a slow speed operation, and controls the capacity changing means so that when the slow speed command is commanded by the slow speed command means in the stop work mode, the pump displacement is smaller than when the slow speed operation is not commanded. You can also.
A travel command means for commanding forward, reverse, and travel neutral of the work machine is provided. When the travel command means commands forward or reverse by the travel command means, the travel work mode is detected, and when travel neutral is commanded. It can also comprise so that a stop work mode may be detected.
The boom can be extended and the second hydraulic actuator can be a boom extension cylinder.

  According to the present invention, the pump capacity of the working hydraulic pump in the travel work mode is made smaller than that in the stop work mode, so that the work efficiency in the stop work mode is improved and the work capacity in the travel work mode is increased. Neutral pressure loss can be reduced, which is efficient.

Hereinafter, an embodiment of a control device for a work machine according to the present invention will be described with reference to FIGS.
FIG. 1 is a side view of a telescopic handler as a work machine according to an embodiment of the present invention. The telescopic handler includes a vehicle body 1, front and rear wheels 2, and a telescopic boom 3 that can extend and retract from the vehicle body 1 so as to be raised and lowered. In FIG. 1, 1A shows a state in which the telescopic boom 3 is turned down and retracted, and 1B shows a state in which the telescopic boom 3 is erected and extended.

  The telescopic boom 3 is provided so as to be pivotable in the vertical direction with the pivot shaft 4 at the rear end of the vehicle body as a fulcrum, and is raised and lowered by driving the boom cylinder 11. The telescopic boom 3 is an expandable and contractible multistage boom having an outer cylinder 3A and an inner cylinder 3B. Inside the telescopic boom 3, a telescopic cylinder 12 having one end fixed to the outer cylinder 3A and the other end fixed to the inner cylinder 3B is disposed along the telescopic direction of the boom 3, and the telescopic boom 3 is telescopic. The cylinder 12 expands and contracts by driving the cylinder 12. The telescopic cylinder 12 needs to expand by an amount corresponding to the maximum expansion amount of the telescopic boom 3, and the capacity of the oil chamber of the telescopic cylinder 12 is relatively large. Note that a single or a plurality of intermediate cylinders may be provided between the outer cylinder 3A and the inner cylinder 3B, and the telescopic boom 3 may have three or more stages.

  A work attachment 7 is attached to the distal end portion of the telescopic boom 3 so as to be pivotable in the vertical direction about a pivot shaft 6 via a bracket 5. The work attachment 7 swings by driving the swing cylinder 13. The work attachment 7 is detachable from the tip of the boom. In FIG. 1, the fork 71 is attached to the tip of the boom, but a bucket 72 can also be attached as shown in FIG. When the fork 71 is attached, an unloading operation (fork operation) is performed as described later, and when the bucket 72 is attached, an excavation operation (bucket operation) is performed. The fork work is usually performed while the vehicle is stopped, and the bucket work is performed while traveling.

  FIG. 2 is a diagram showing a schematic configuration of the control device according to the embodiment of the present invention. A variable displacement travel pump (HST pump 21) and a variable displacement work pump 22 are connected to the output shaft of the engine 20. These pumps 21 and 22 are driven by the engine 20, and the rotational speeds of the pumps 21 and 22 increase as the engine rotational speed increases. The pressure oil from the HST pump 21 is supplied to the traveling motor 23, and the traveling motor 23 is driven. The driving force of the travel motor 23 is transmitted to the wheels 2 via the transmission 24 and the front and rear axles 25, 26, and the vehicle travels.

  The pump capacity (for example, the amount of pump tilt) of the HST pump 21 is controlled by the capacity control device 21a. The capacity control device 21a includes a tilt adjustment cylinder and a forward / reverse switching valve that switches in conjunction with the operation of the forward / reverse switching lever. As shown in FIG. 3, the forward / reverse switching lever 31 is provided below the steering handle 35 and on the left side of the steering column, and is rotated from the neutral position forward (forward position) and backward (reverse position) as indicated by the arrows in the figure. Is possible. When the forward / reverse switching lever 31 is operated to the neutral position, the forward / reverse switching valve is switched to the neutral position, and the tilt adjustment cylinder is controlled so that the HST pump 21 is tilted to zero, and the pump discharge amount is set to zero. .

  When the forward / reverse switching lever 31 is operated to the forward movement position or the reverse movement position, the forward / reverse switching valve switches to the forward movement position or the reverse movement position, controls the operation direction of the tilt adjustment cylinder, and changes the tilt direction of the HST pump 21. Control. At this time, a control pressure is supplied to the tilt adjustment cylinder via the forward / reverse switching valve, and the pump tilt amount is controlled according to the control pressure. The control pressure increases as the engine speed increases, and the pump tilt increases as the control pressure increases. As a result, when the engine speed increases, both the rotation speed of the HST pump 21 and the pump tilt amount increase, the pump discharge amount increases, and smooth acceleration traveling becomes possible. The engine speed is adjusted by operating an accelerator pedal (not shown).

  Pressure oil from the working hydraulic pump 22 is supplied to the boom cylinder 11, the telescopic cylinder 12, and the swing cylinder 13 through the control valves 11a to 13a, respectively. The control valves 11a to 13a are switched by operating the operation levers 11b to 13b, respectively, and the supply of pressure oil to the cylinders 11 to 13 is controlled according to the operation of the operation levers 11a to 13b. When the operation levers 11b to 13b are not operated, the control valves 11a to 13a are switched to the neutral position, and supply of pressure oil to the cylinders 11 to 13 is blocked.

  The pump capacity (for example, the pump tilt amount) of the hydraulic pump 22 is controlled by the regulator 22a. The self-pressure of the pump 22 acts on the regulator 22a, and horsepower control is performed. The horsepower control is PQ control as shown by the solid line in FIG. 4, and the regulator 21a sets the pump tilt amount q so that the load determined by the pump discharge pressure P and the pump discharge amount Q does not exceed the engine output. Be controlled.

  The regulator 22a has a maximum capacity limiting unit, and the pump pressure is applied to the maximum capacity limiting unit by switching the electromagnetic valve 27, and the maximum tilt of the pump 22 is controlled in two stages of large (q0) or small (q1). . That is, when the solenoid valve 27 is off, the maximum pump tilt is q0, and the pump discharge amount under a predetermined engine speed is Q0 in FIG. When the solenoid valve 27 is on, the maximum pump tilt is q1, and the pump discharge amount is Q1 (<Q0) in FIG. Note that q0 is the maximum tilt determined by the specifications of the pump itself.

  The solenoid valve 27 is switched by a signal from the control device 30. The control device 30 is supplied with signals from a detector 33 that detects the operation of the forward / reverse switching lever 31 and a selector switch 32 that commands a slow speed operation. The changeover switch 32 is provided on the operation panel on the right side of the steering wheel 35 as shown in FIG. 3, and outputs an ON signal or an OFF signal in accordance with the switch operation. A change-over switch 32 may be provided in the grips of the operation levers 11b to 13b, whereby a low speed operation can be commanded without releasing the hands from the operation levers 11b to 13b.

  FIG. 5 is a flowchart illustrating an example of processing executed by the control device 30. This flowchart is started by turning on an engine key switch, for example. In step S1, the operation of the forward / reverse switching lever 31 is determined based on the signal from the detector 33. This determination is a determination of the work mode. That is, when the forward / reverse switching lever 31 is in the neutral position, it is determined that the vehicle is in the stopped work mode, and when it is in the forward position or the reverse position, it is determined as the traveling work mode that is performed in the traveling state. If it is determined in step S1 that the forward / reverse switching lever 31 is in the forward drive position or the reverse drive position, that is, if it is determined in the traveling work mode, the process proceeds to step S2 and the electromagnetic valve 27 is turned on. As a result, the maximum tilt of the hydraulic pump 22 is small, that is, q1.

  On the other hand, if it is determined in step S1 that the forward / reverse switching lever 31 is in the neutral position, that is, the stop work mode, the process proceeds to step S3, and a signal from the changeover switch 32 is determined. If it is determined that the ON signal is output from the changeover switch 32, that is, if there is a slow speed operation command, the process proceeds to step S2, and if the OFF signal is determined to be output, the process proceeds to step S4. In step S4, the solenoid valve 27 is turned off. As a result, the maximum tilt of the hydraulic pump 22 is large, that is, q0.

The operation of the control device according to the present embodiment will be described more specifically.
(1) Fork Work First, a case will be described in which a fork 71 is attached to the tip of the telescopic boom 3 as shown in FIG. That is, fork work which is an example of the stop work mode will be described. Fork work, the vehicle travels to the front of the load placed on the pallet, inserts the tip of the fork 71 into the bottom of the pallet, and then operates the forward / reverse switching lever 31 to the neutral position to stop the vehicle. Perform in the state. For this reason, the electromagnetic valve 27 is turned off during fork work, and the maximum tilt of the pump 22 is controlled to q0 (step S4).

  When the load on the pallet is piled up on the platform 8 in the above-described state, first, the fork 71 is moved to the near side by holding the load as shown by the arrow 6a by raising the boom 3 or swinging the fork 71. Defeat and lift the load from the ground. When the load is installed at a place away from the table 8, the vehicle is moved to the front of the table 8 after the load is lifted from the ground as described above, and then the forward / reverse switching lever 31 is moved. By operating to the neutral position, the stop work mode may be set.

  Next, by raising and extending the boom 3, the load is raised vertically as indicated by the arrow 6b. Next, as shown by an arrow 6c, the load is moved in the horizontal direction by turning and extending the boom 3. Thereafter, the pallet is placed on the table 8 as shown by the arrow 6d by turning the boom 3 and swinging the fork 71. Next, the fork 71 is pulled out from the lower side of the pallet as shown by the arrow 6e by raising and retracting the boom 3. Next, the fork 71 is vertically lowered as shown by the arrow 6f by the folding and retracting operation of the boom 3. The load lifting operation is thus completed. After that, when lifting another load, the same operation is repeated.

  When unloading the load placed on the base 8, the boom 3 and the fork 71 may be operated in the reverse order as described above. That is, the boom 3 is raised and extended to raise the fork 71, and then the boom 3 is turned and extended to insert the fork 71 below the pallet. Next, the boom 3 is raised and the fork 71 is swung to lift the pallet, and the boom 3 is raised and retracted to horizontally move the load to the front side. Next, the boom 3 is turned and retracted to move the load vertically downward, and the fork 71 swings to lower the load on the floor.

  The operations of the cylinders 11 to 13 at the time of the fork work described above may be performed independently or simultaneously by a combined operation. In this case, during the fork operation, the maximum tilt of the hydraulic pump 22 is q0, and the pump discharge amount under a predetermined engine speed is Q0. For this reason, the moving speed of the fork 71 when loading and unloading can be increased, and the working efficiency is improved. In particular, the telescopic handler has a large effect of improving the work efficiency by increasing the pump discharge amount because the telescopic cylinder 12 has a large expansion / contraction amount.

  Of the above operations, the operation of pulling out the fork 71 from the lower side of the pallet and the operation of inserting the fork 71 need to be performed slowly. When performing this operation, the operator operates the changeover switch 32. As a result, the maximum inclination of the hydraulic pump 22 becomes q1, and the pump discharge amount decreases from Q0 to Q1 (step S2). For this reason, the drive speed of each cylinder 11-13 becomes low speed, and very low speed operation becomes easy.

(2) Bucket Work Next, a case where excavation work is performed with the bucket 72 attached to the tip of the telescopic boom 3 as shown in FIG. 7 will be described. That is, the bucket work which is an example of the traveling work mode will be described. The bucket operation is performed while the vehicle is moving forward and backward by switching the forward / reverse switching lever 31 to the forward position or the reverse position. For this reason, the electromagnetic valve 27 is turned on during the bucket operation, and the maximum tilt of the pump 22 is controlled to q1 (step S2).

  When performing bucket work, first, the bucket 72 is set in a horizontal state toward the earth and sand as shown in FIG. 7a. Then, in a state where the forward / reverse switching lever 31 is operated to the forward position, the vehicle is caused to travel forward toward the earth and sand as shown in FIG. Next, while the vehicle is traveling forward, the boom 3 is raised and the bucket 72 is swung forward (cloud). Thereby, as shown to 7c of a figure, the boom 3 is stood up and earth and sand are taken in in a bucket. Next, after operating the forward / reverse switching lever 31 to the reverse position, the vehicle is driven backward by operating the accelerator pedal. Further, the bucket 72 is moved downward as shown in FIG.

  Thereafter, the forward / reverse switching lever 31 is operated to the forward movement position, the steering handle 35 and the accelerator pedal are operated to move the vehicle forward toward a predetermined earthing position, and the boom 3 is moved by the standing operation of the boom 3. Stand up. Next, as shown in 7e of the figure, the bucket 72 is set to a horizontal position by swinging the bucket 72 (cloud) after releasing the earth and sand in the bucket by swinging the bucket 72 (dump). . Next, the forward / reverse switching lever 31 is operated to the reverse position, the vehicle is moved backward by operating the accelerator pedal, and the bucket 72 is returned to the state of 7a in FIG. Thereafter, the same operation is repeated.

  During the above bucket operation, only the boom cylinder 11 and the swing cylinder 13 are operated. The operations of the cylinders 11 and 13 may be performed independently or simultaneously by a combined operation. Since the maximum tilt of the hydraulic pump 22 decreases from q0 to q1 during bucket operation, the discharge amount of the hydraulic pump 22 is forcibly reduced, and the pressure loss of the pressure oil in the neutral control valve 12a, that is, the neutral pressure loss is reduced. can do. In this case, since it is not necessary to drive the telescopic cylinder 12 having a large cylinder capacity during the bucket operation, the excavation operation can be performed without any problem even if the pump discharge amount is reduced. Further, since the pump capacity is reduced without reducing the engine speed, the traveling operation is not adversely affected.

According to the present embodiment, the following operational effects can be achieved.
(1) When the forward / reverse switching lever 31 is in the forward position or the reverse position, the maximum tilt of the working pump 22 is made smaller than in the neutral position. As a result, the pump discharge amount during the bucket operation is reduced, and the neutral pressure loss of the control valve 12a is reduced, which is efficient. In addition, the boom 3 can be quickly expanded and contracted during fork work, and work efficiency is improved. In this case, since it is not necessary to extend and retract the boom 3 during the bucket operation, there is no problem that the work efficiency is deteriorated.
(2) During the fork operation, the maximum tilt of the pump is decreased from q0 to q1 by operating the changeover switch 32. As a result, the fork 71 can be easily inserted into or pulled out from the bottom of the pallet by a slow speed operation.
(3) Since the pump maximum tilt is controlled in accordance with the operation position of the forward / reverse switching lever 31, there is no need for a separate operation for instructing the pump maximum tilt, and no complicated operation is required.

  In the above embodiment, the operation mode (stopping operation mode, traveling operation mode) is detected by detecting the operation position of the forward / reverse switching lever 31 with the detector 33. For example, the operation mode setting device The operation mode may be detected by detecting this setting operation, and the configuration of the detection means is not limited to that described above. Although the maximum tilt of the hydraulic pump 22 is controlled by switching the electromagnetic valve 27, any capacity changing means may be used as long as the pump capacity is changed. The pump tilt itself may be controlled instead of the maximum tilt. If the pump capacity is made smaller in the traveling work mode than in the stop work mode, the processing in the control device 30 as the control means is not limited to the above.

  Although the slow speed operation is commanded by operating the changeover switch 32, the slow speed operation may be commanded by other than the switch operation (for example, voice or the like), and the configuration of the slow speed command means is not limited to this. Although the vehicle is commanded to move forward and backward and neutral by the forward / reverse switching lever 31, it may be performed by other travel command means. Although the case where the fork 71 and the bucket 72 are attached to the boom tip has been described above, other work attachments can be attached. Further, the present invention can be similarly applied to work machines other than the telescopic handler. Accordingly, the boom cylinder 11 and the swing cylinder 13 are driven in the stop work mode and the travel work mode, and the extension cylinder 12 is driven only in the stop work mode. However, the first hydraulic actuator and the second hydraulic actuator are used. Is not limited to this.

  In the above embodiment, the traveling motor 23 is driven by the HST pump 21 to travel the vehicle. However, the engine output may be transmitted to the transmission 24 via the torque converter to travel the vehicle. Instead of operating the accelerator pedal, the gin rotational speed may be set by operating a manual dial or the like, and the operation may be performed under a constant engine rotational speed, that is, a constant rotational speed of the hydraulic pump 22. That is, as long as the features and functions of the present invention can be realized, the present invention is not limited to the control device for the work machine according to the embodiment.

The side view of the telescopic handler which is an example of the working machine which concerns on embodiment of this invention. The figure which shows schematic structure of the control apparatus which concerns on embodiment of this invention. The figure which shows arrangement | positioning of the operation member in a driver's cab. The figure which shows the PQ characteristic of the working hydraulic pump of FIG. The flowchart which shows an example of the process performed with the control apparatus of FIG. The figure which shows an example of operation | movement of a fork work. The figure which shows an example of operation | movement of a bucket operation | work.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Boom cylinder 12 Telescopic cylinder 13 Oscillating cylinder 22 Working hydraulic pump 22a Regulator 27 Solenoid valve 30 Control device 31 Forward / reverse switching lever 32 Changeover switch 33 Detector 71 Fork 72 Bucket

Claims (4)

A variable displacement working hydraulic pump;
A first hydraulic actuator driven by pressure oil from the hydraulic pump, respectively, in a stop work mode in which work is performed in a stop state and in a travel work mode in which work is performed in a travel state;
A second hydraulic actuator driven by pressure oil from the hydraulic pump only during the stop operation mode;
Detection means for detecting the work mode;
Capacity changing means for changing the pump capacity of the hydraulic pump;
Control means for controlling the capacity changing means so that the pump capacity becomes smaller when the traveling work mode is detected by the detecting means than when the stop work mode is detected. Control device for work machines. The work machine control device according to claim 1,
Provided with a slow speed command means for commanding a slow speed operation,
The capacity control means controls the capacity changing means so that when the slow speed operation is commanded by the slow speed commanding means in the stop operation mode, the pump capacity is smaller than when the slow speed operation is not commanded. A control device for work machines. The work machine control device according to claim 1 or 2,
Travel command means for commanding forward, reverse, and travel neutral of the work machine,
The control device for a work machine, wherein the detection means detects the traveling work mode when a forward or reverse movement is instructed by the traveling command means, and detects the stop working mode when a traveling neutral is instructed. . In the control apparatus of the working machine according to any one of claims 1 to 3,
The work machine has a telescopic boom,
The control device for a working machine, wherein the second hydraulic actuator is a boom telescopic cylinder.

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