JP2012207491A - Travel control device of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the same slow start function as that during double-traveling even during single-traveling.SOLUTION: A hydraulic shovel moves forward and backward by means of a travel unit using left and right traveling motors 4, 5 as driving sources, and a travel control device of this hydraulic shovel delays response of the traveling motors 4, 5 to the operation of travel remote control valves 6, 7 during traveling and perform a delay processing to make a lower structure slowly start. The travel control device is constituted in order to select one of two kinds of delay processing characteristics according to double-traveling and single-traveling such that the rise of starting speed becomes same at a both-traveling time when the left and right traveling motors 4, 5 are driven simultaneously and in the same direction and at a single-traveling time when only one of the traveling motors 4, 5 is driven.

Description

  The present invention relates to a traveling control device for a construction machine including a crawler traveling body such as a hydraulic excavator.

  The background art will be described using a hydraulic excavator as an example.

  The hydraulic excavator is mounted on a crawler type lower traveling body so that the upper swinging body can swing around an axis perpendicular to the ground, and a drilling attachment equipped with a boom, an arm, and a bucket is attached to the upper swinging body. Configured.

  The lower traveling body includes left and right crawler traveling devices, and both the crawler traveling devices are driven by separate traveling motors (hydraulic motors) using a hydraulic pump as a drive source.

  These two traveling motors are rotated in the direction and speed by switching the control valve based on the operation of individual operating means (normally a remote-controlled valve operated by a lever, which will be described in this example) provided on the upper swing body. Is controlled.

  In this hydraulic excavator, there occurs a situation in which the operation direction of the remote control valve and the traveling direction of the lower traveling body are reversed due to the turning of the upper rotating body.

  That is, a situation in which the operator intends to move forward moves backward or vice versa.

  In this case, it is not preferable to start the vehicle at the same rising speed (acceleration) as that during normal traveling because the operator has no room for recognizing an erroneous operation and correcting it.

  As countermeasures against this point, the applicant, at the time of traveling start, slowly slows the rising of the traveling motor speed by giving a delay in response to the pump discharge amount or control valve switching with respect to the operation of the remote control valve. Proposed a slow start system to start (see Patent Document 1)

JP 2000-319940 A

  In the above-mentioned known technology, the traveling operation is performed regardless of both the traveling time in which both traveling motors are simultaneously driven in the same direction (straight traveling) and the single traveling time in which only one traveling motor is driven (in the pivot turn). If there is, it is configured to start slowly with the same characteristics.

  However, during one-way travel, the travel load is much larger than when traveling straight, and the required travel torque also increases. Therefore, the vehicle begins to move after further delay from the targeted response delay.

  In other words, after the start delay that exceeds the delay time for slow start, it will start suddenly, the slow start control can not be utilized, and the original purpose of preventing erroneous operation (notifying the operator of correct operation) Cannot be achieved.

  Therefore, the present invention provides a traveling control device for a construction machine that can ensure the same slow start function as that during both travelings even during one traveling.

  As means for solving the above-described problems, in the present invention, the left and right traveling motors using the left and right traveling motors as drive sources are used to travel forward and backward, and left and right traveling that individually command the operation of both the traveling motors. Based on the operation means, the operation detection means for detecting the operation of the left and right travel operation means, and the signal from the operation detection means, the response of the travel motor to the operation of the travel operation means is delayed during travel to loosen the traveling body. In the traveling control apparatus for a construction machine, comprising a control means for performing a delaying process for starting, the control means is driven during both travels in which the left and right travel motors are simultaneously driven in the same direction, and only one travel motor is driven. The characteristic of the delay processing is made different according to both the traveling and the one-way traveling so that the starting speed rises at the same time during the one-way traveling. .

  In this way, paying attention to the fact that the traveling load is larger and the rise of speed is slower than that of both runs during one run, so that the start speed rise (speed gradient) during this one run is the same as during both runs. Since the delay processing characteristics are made different from each other, the same slow start function can be ensured even during one traveling as in both traveling, and erroneous operation can be prevented.

  In the present invention, a hydraulic motor using a hydraulic pump as a hydraulic source is used as the left and right traveling motors, and a remote control valve using a pilot pump as a pressure source is used as the operating means. The control means controls the rotational direction and speed of the travel motor, and the control means controls the pilot pressure with respect to the operation of the remote control valve according to both travel and single travel. It is desirable that the delay processing has different characteristics (claims 2 to 4).

  In this way, if the pilot pressure control system that makes the delay processing characteristics different during both traveling and single traveling by pilot pressure control of the control valve is adopted, control is easy because of low pressure control, and control response is good. It will be a thing.

  In this case, an electromagnetic proportional pressure reducing valve for controlling the pilot primary pressure sent to the remote control valve is provided in the pilot pump circuit connecting the pilot pump and the remote control valve, and the control means is adapted for both travel and single travel. The pilot primary pressure delay processing characteristic for the operation of the remote control valve may be made different (Claim 3), or a pilot circuit connecting the remote control valve and the control valve may be connected to the control valve. An electromagnetic proportional pressure reducing valve for controlling the pilot pressure to be sent is provided, and the control means is configured to vary the delay processing characteristics of the pilot pressure with respect to the operation of the remote control valve according to both traveling and one traveling. (Claim 4).

  According to the former configuration that controls the pilot primary pressure, the left and right control valves can be controlled by one electromagnetic proportional pressure reducing valve, so that the cost can be reduced.

  Alternatively, as another control method, a variable displacement pump whose discharge amount is controlled by a regulator is used as the hydraulic pump, and the control means responds to the operation of the remote control valve according to both traveling and single traveling. The delay characteristic of the pump discharge amount may be made different (Claim 5), or the hydraulic pump may be driven by an engine, and the control means may be used for both traveling and single traveling. Accordingly, the delay processing characteristic of the engine speed with respect to the operation of the remote control valve may be made different (claim 6).

  According to this configuration, it is only necessary to control the existing equipment such as the regulator or the governor of the engine, and the control equipment to be added for the slow start is unnecessary, so that the cost can be reduced.

  According to the present invention, the same slow start function as that during both travelings can be ensured even during one traveling to prevent erroneous operation and to improve safety.

It is a circuit block diagram which shows 1st Embodiment of this invention. It is a figure which shows the relationship between the output of the pilot pressure sensor in 1st Embodiment, and the command electric current of an electromagnetic proportional pressure reducing valve. It is a figure which shows the change condition of the traveling speed with respect to progress of time as a control result by the embodiment. It is a flowchart for demonstrating the effect | action of the embodiment. It is a circuit block diagram which shows 2nd Embodiment of this invention. It is a circuit block diagram which shows 3rd Embodiment of this invention. It is a circuit block diagram which shows 4th Embodiment of this invention.

  The embodiment is applied to a hydraulic excavator.

  FIG. 1 shows a traveling circuit of this hydraulic excavator, in which a traveling drive system is indicated by a solid line, a pilot system is indicated by a broken line, and a control system is indicated by a solid line with diagonal lines.

  In this circuit, a main hydraulic pump 2 as a traveling hydraulic power source and a pilot pump 3 as a pilot pressure source are driven by an engine 1, and left and right traveling motors (hydraulic motors) 4 are driven by pressure oil discharged from the hydraulic pump 2. , 5 are driven.

  Between the hydraulic pump 2 and the both travel motors 4 and 5, hydraulic pilot type left travel and right travel control valves individually operated by left and right travel remote control valves 6 and 7 as operating means. 8 and 9 are provided, and the control valves 8 and 9 control the rotational direction and rotational speed of the traveling motors 4 and 5, that is, the forward / reverse switching of the lower traveling body and the traveling speed. In FIG. 1, T is a tank.

  The hydraulic pump 2 is configured as a variable displacement pump whose discharge amount is changed by a tilt adjusting action by the regulator 10 as a standard specification of the hydraulic excavator, and the discharge amount is controlled by a controller 11 as a control unit based on various sensor signals. The

  However, in the first embodiment, this pump control is irrelevant to the slow start, so a detailed description is omitted.

  The pilot pump 3 and the left and right remote control valves 6 and 7 include a pilot pump circuit 12 that discharges pilot oil from the pilot pump 3 and a pilot primary pressure circuit 13 that distributes the discharged pilot pump oil to both remote control valves 6 and 7. , 14 and the pilot primary pressure sent from the pilot pump 3 is reduced in accordance with the operation amount of the remote control valve, and the secondary pressure (pilot pressure) is pilot pilot ports 15 and 16 of the control valves 8 and 9. Configured to send to.

  As a result, the control valves 8 and 9 are switched and controlled in accordance with the operation of the remote control valves 6 and 7, and the operation (forward / reverse and its speed) of both the traveling motors 4 and 5 is controlled.

  In the first embodiment, the pilot pump circuit 12 is provided with an electromagnetic proportional pressure reducing valve (hereinafter simply referred to as a proportional valve) 17 and a pilot as operation detecting means for detecting the pilot pressure from the left and right remote control valves 6 and 7. Pressure sensors 18 and 19 are provided, and the secondary pressure of the proportional valve 17, that is, the pilot primary pressure sent to the remote control valves 6 and 7 is controlled by a control signal from the controller 11 based on the outputs from both the sensors 18 and 19. It is comprised so that.

  FIG. 2 shows the relationship between the sensor output when the remote control valves 6 and 7 are fully operated and the current sent from the controller 11 to the proportional valve 17 based on the sensor output.

  FIG. 3 shows the rising characteristics of the traveling speed with respect to the passage of time as a result.

  2 and 3, the broken line indicates a case where no delay process is applied. In FIG. 2, the solid line indicates the proportional valve current during both travels, and the thick line indicates the proportional valve current during one travel.

  When the delay process is not applied, as shown by the broken line in FIG. 2, when the remote control valves 6 and 7 are operated (running operation), the proportional valve current rises with almost no delay.

  As a result, as shown by the broken line in FIG. 3, the traveling speed rapidly rises as soon as the full lever is operated.

  On the other hand, according to the embodiment, during traveling, a delay process is performed in which the proportional valve current is gently increased with respect to the sensor output as indicated by the solid line and the thick line in FIG.

  As a result, as shown by the solid line in FIG. 3, the traveling speed rises with a gentle speed gradient α from the point of full lever operation. That is, “slow start” is performed to start slowly.

  As a result, for example, even if the operator moves backward (or moves forward) with the intention of moving forward (or moving backward) with the direction of the upper turning body reversed, he notices an erroneous operation within a short moving distance, and immediately corrects it (stops running). Or reverse operation).

  In this case, when only one of the left and right traveling motors 4 and 5 is driven, the traveling load is much larger than that during both traveling and the necessary traveling torque is increased. It starts moving after being further delayed from the response delay.

  That is, after the start delay exceeding the delay time for slow start, the vehicle starts suddenly and the slow start function cannot be used.

  Therefore, in this embodiment, the delay processing characteristics are different for both traveling and one traveling.

  That is, as shown by the solid line in FIG. 2, the controller 11 has a delay processing characteristic I for both travelings where the rise of the proportional valve current is gentle, and a delay processing characteristic (I) for covering the starting delay during one traveling. The delay processing characteristic (II) for one-way running that makes the rise of the proportional valve current steeper than that is set and stored in advance, and the delay processing characteristic I for both driving and the delay processing characteristic II for one-way driving, respectively. By selecting and executing, the slow start function having the speed gradient α shown in FIG.

  The operation of the controller 11 at this point will be described with reference to the flowchart of FIG.

  After the control is started, it is determined in step S1 whether the left or right traveling operation has been performed based on the outputs from the pilot pressure sensors 18, 19, and if NO (no operation), the process returns to step S1, and YES (operation is present). ), The process proceeds to step S2.

  In step S2, a difference (differential pressure) ΔP between the left and right traveling pilot pressures is obtained. In subsequent step S3, it is determined whether or not the differential pressure ΔP is smaller than a set value (both traveling or single traveling).

  If it is determined YES (both traveling), the delay processing characteristic (I) is selected and executed in step S4, and the process returns to step S1.

  On the other hand, if NO (one-way running) is determined, the delay processing characteristic (II) is selected and executed in step S5, and the process returns to step S1.

  In this way, by making the delay processing characteristics different between the two travelings and the one traveling, the same slow starting function can be ensured with the same starting speed rising, and erroneous operation can be prevented.

  Assuming that the full lever is operated during both travel and single travel, the pilot differential pressure ΔP is obtained as described above and compared with the set value as a method for determining whether the travel is either double travel or single travel. Instead of the processing to be performed, it may be determined whether the vehicle is traveling in both directions or only in traveling, depending on whether there is an output from both pilot pressure sensors 18 and 19 or only from one of them.

Second embodiment (see FIG. 5)
In the following embodiments, only differences from the first embodiment will be described.

  In the second embodiment, electromagnetic proportional pressure reducing valves (proportional valves) 20 and 21 are provided in the left and right pilot circuits 15 and 16, respectively, and both proportional valves 20 and 21 are individually controlled by the controller 11.

  That is, the pilot pressure sent from the remote control valves 6 and 7 to the control valves 8 and 9 is controlled by both proportional valves 20 and 21, and the pilot pressure is delayed with respect to the operation of the remote control valve according to both traveling and one traveling. The processing characteristic is selected from the characteristics (I) and (II).

  Specifically, both proportional valves 20 and 21 are simultaneously controlled according to the delay processing characteristic (I) of FIG. 2 during both travelings, and only the proportional valve 20 or 21 on the side operated for traveling during one traveling is the delay processing characteristic (II). ) Controlled according to.

  Also with this configuration, as in the first embodiment, the basic effect of ensuring the same slow start function as during both travelings can be obtained even during one traveling.

  However, according to the first embodiment, since the left and right control valves 8 and 9 can be controlled by one proportional valve 17, there is an advantage that the cost can be reduced compared to the second embodiment.

Third embodiment (see FIG. 6)
In the third embodiment, a configuration in which the relationship between the sensor output and the discharge amount of the hydraulic pump 2 is delayed with different characteristics for both travel and single travel, that is, the rise of the pump discharge amount with respect to the sensor output is moderated, and This rising characteristic is different between both traveling and one traveling.

  Specifically, when the controller 10 is controlled by the controller 11 and the vertical axis of FIG. 2 is the pump discharge amount, the pump discharge amount is increased at a gentle rise shown by the solid line in FIG. As shown by the thick line in FIG. 2, the vehicle is configured to increase at a steep rise as compared with the case of both travelings.

Fourth embodiment (see FIG. 7)
In the fourth embodiment, the relationship between the sensor output and the engine speed is delayed with different characteristics for both travel and single travel, that is, the rise of the engine speed with respect to the sensor output is moderated, and this rise The configuration is such that the characteristics are different for both traveling and single traveling.

  Specifically, the controller 11 controls the governor control unit 22 that controls the engine speed, and when the vertical axis in FIG. 2 is the engine speed, the engine speed is shown by a solid line in FIG. In contrast to the increase at a gentle rise, as shown by the bold line in FIG.

  Both the third and fourth embodiments can provide basically the same effects as the first embodiment.

  In addition, according to both the third and fourth embodiments, the existing equipment (the regulator 10 or the governor control unit 22) is controlled, and the control equipment to be added for the slow start is unnecessary, so the cost is reduced. It's cheap.

  As another control method, a configuration may be adopted in which a flow rate control valve is provided between the control valves 8 and 9 and the traveling motors 4 and 5 and a delay process is performed on the flow rate supplied to the traveling motors 4 and 5.

  Further, a slow start release switch may be provided so that the function can be canceled in a situation where the slow start function is unnecessary.

  On the other hand, the present invention is not limited to an all-hydraulic excavator in which the engine 1 drives the hydraulic pump 2 to drive the traveling motors (hydraulic motors) 4 and 5, but also a hybrid excavator that uses both engine power and battery power, and engine drive The present invention can also be applied to an electric excavator or a battery excavator that drives a traveling motor (electric motor) with electric power from a generator or commercial power source or battery power.

  Further, the present invention can be applied not only to the shovel but also to other construction machines such as a dismantling machine and a crusher configured with the shovel as a base.

  When an electric motor is used as the traveling motor, for example, the electric motor current may be controlled in the same manner as the delay processing characteristics (I) and (II) in FIG. 2 with respect to the sensor output.

DESCRIPTION OF SYMBOLS 1 Engine 2 Hydraulic pump 3 Pilot pump 4 Left and right traveling motors 6, 7 Remote control valve as traveling operation means 8, 9 Control valve 10 Regulator 11 Controller as controlling means 12 Pilot pump circuit 15, 16 Pilot circuit 17 Electromagnetic proportional pressure reducing valve 18, 19 Pilot pressure sensor as operation detecting means 20, 21 Proportional pressure reducing valve 22 Governor control unit for controlling engine speed

Claims (6)

  A traveling body that moves forward and backward by left and right traveling devices that use left and right traveling motors as drive sources, left and right traveling operation means that individually command the operation of both traveling motors, and operations of the left and right traveling operation means. Construction comprising operation detecting means for detecting, and control means for performing delay processing for slowly starting the traveling body by delaying the response of the traveling motor to the operation of the traveling operation means during traveling based on a signal from the operation detecting means In the machine travel control device, the control means may start up the starting speed when both the left and right hydraulic motors are simultaneously driven in the same direction and when only one hydraulic motor is driven. A traveling control device for a construction machine, characterized in that the characteristics of the delay processing are made different according to both traveling and single traveling so as to be the same.   A hydraulic motor using a hydraulic pump as a hydraulic source is used as the left and right traveling motors, and a remote control valve using a pilot pump as a pressure source is used as the operating means, and a hydraulic pilot control valve is operated by a pilot pressure sent from the remote control valve. And configured to control the rotational direction and speed of the travel motor, and the control means has a characteristic of delay processing of the pilot pressure with respect to the operation of the remote control valve according to both travel and single travel. 2. The traveling control device for a construction machine according to claim 1, wherein the traveling control device is configured to be different.   The pilot pump circuit connecting the pilot pump and the remote control valve is provided with an electromagnetic proportional pressure reducing valve that controls a pilot primary pressure sent to the remote control valve, and the control means is configured to 3. The traveling control device for a construction machine according to claim 2, wherein the pilot primary pressure delay processing characteristic with respect to the operation of the remote control valve is made different.   An electromagnetic proportional pressure reducing valve for controlling a pilot pressure sent to the control valve is provided in a pilot circuit connecting the remote control valve and the control valve, and the control means controls the remote control according to both traveling and single traveling. 3. The traveling control device for a construction machine according to claim 2, wherein the delay processing characteristics of the pilot pressure with respect to the operation of the valve are made different.   As the hydraulic pump, a variable displacement pump whose discharge amount is controlled by a regulator is used, and the control means has a delay processing characteristic of the pump discharge amount with respect to the operation of the remote control valve according to both traveling and single traveling. 2. The traveling control device for a construction machine according to claim 1, wherein the traveling control device is configured to be different.   The hydraulic pump is configured to be driven by an engine, and the control means is configured to vary delay processing characteristics of the engine speed with respect to the operation of the remote control valve according to both traveling and single traveling. The traveling control device for a construction machine according to claim 1.

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