JP5371210B2 - Hydraulic construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform both an operation performed by the combined control of a specific actuator and the other actuator, and an operation performed by the single control of the specific actuator at a high operating speed by providing a relatively-low-output prime mover. <P>SOLUTION: This hydraulic construction machine is equipped with a number-of-revolutions-of-prime-mover control means which controls the number of revolutions of the prime mover 22 for a hydraulic pump to the first constant number N1 of revolutions for enabling the combined control of drive motors 13 and 14 and a boom cylinder 32 etc., when control inputs of drive motors 13 and 14 are equal to or lower than a first control input which controls the number of the revolutions of the prime mover 22 to the second large constant number N2 of revolutions, when the control inputs of drive motors 13 and 14 are equal to or higher than a second control input higher than the first control input, and controls the number of the revolutions of the prime mover 22 so that the number of the revolutions of the prime mover 22 can become gradually larger depending on an increase in the control inputs of the drive motors 13 and 14, when the control inputs of the drive motors 13 and 14 are larger than the first control input and smaller than the second control input. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a hydraulic construction machine such as a hydraulic excavator that includes a prime mover and a hydraulic pump that is driven by the prime mover, and that can control the number of revolutions of the prime mover according to the amount of operation of an operating device.

There exists a thing shown by patent document 1 as this kind of prior art. This patent document 1 discloses a configuration for controlling the rotational speed of a prime mover according to the operation amount of each actuator operating device, that is, the operation state and the operation content.
JP 2002-266379 A

  In the prior art disclosed in Patent Document 1 described above, since control for simply increasing / decreasing the rotational speed of the prime mover according to increase / decrease in the operation amount of the operating device is performed, the maximum torque of the hydraulic pump and the rotational speed of the prime mover are controlled. The maximum load acting on the prime mover represented by the product increases as the rotational speed of the prime mover increases. In this case, the prime mover must have an output characteristic corresponding to the maximum load, and even when the prime mover speed is increased only during low-use operations such as traveling alone operation on a hydraulic excavator, a large output corresponding to the maximum load A prime mover will be provided.

  For example, in a battery-driven hydraulic excavator, a continuous operation time for performing a combined operation of a specific actuator such as a left and right traveling motor and another actuator different from the left and right traveling motor, such as an actuator for driving a front work machine, is increased by battery power. In order to meet this demand, there is a case where a lower rotational speed than that of an engine type hydraulic excavator of the same size is set as the rated rotational speed. In such a battery-driven hydraulic excavator, when performing the combined operation of the specific actuator and the other actuator described above, the operating speed of the left and right traveling motor, which is the specific actuator, that is, the traveling speed is relatively low. However, when traveling alone such as when crossing public roads, it is desirable to increase the traveling speed in order to reduce adverse effects on traffic. In this way, even if the rotational speed of the prime mover is increased only during the single operation of the motor, it is possible to save energy for a long time by setting a slightly low rotational speed to the rated rotational speed. A prime mover will be provided in accordance with the maximum output during single driving operation.

  That is, in the prior art, when considering a hydraulic construction machine including a specific actuator and a plurality of actuators including other actuators different from the specific actuator, a long time is required due to the combined operation of the specific actuator and other actuators. The rated rotation speed during energy saving work over a wide range may be set to a little lower, and it may be possible to operate a specific actuator at a high operating speed. In spite of the low frequency of the single operation, there is a problem that a large output prime mover corresponding to the maximum output at the time of the single operation of the specific actuator is provided, which increases the equipment cost.

  The present invention has been made from the actual situation in the above-described prior art, and its purpose is to produce relatively small outputs of both work by a combined operation of a specific actuator and another actuator and a single operation of the specific actuator at a high operating speed. It is to provide a hydraulic construction machine that can be realized by providing a prime mover.

In order to achieve this object, the present invention provides a prime mover, a hydraulic pump driven by the prime mover, a specific actuator driven by pressure oil discharged from the hydraulic pump, and other different from the specific actuator. In a hydraulic construction machine including a plurality of actuators including an actuator and a specific operation unit that operates the specific actuator, when the operation amount of the specific operation unit is equal to or less than a first operation amount, the rotational speed of the prime mover is When the operation amount of the specific operation means is greater than or equal to the second operation amount that is greater than the first operation amount, the control is performed to a constant first rotation speed that enables a combined operation of the specific actuator and the other actuator. The rotational speed of the prime mover is controlled to a constant second rotational speed higher than the first rotational speed, and the operation amount of the specific operation means is the first When the operation amount is larger than the work amount and smaller than the second operation amount, the operation amount is gradually increased between the first rotation speed and the second rotation speed as the operation amount of the specific operation means increases. A motor rotation speed control means for controlling the rotation speed of the prime mover, wherein the rotation speed of the prime mover is set to the second rotation speed (in response to an operation amount of the specific operation means being equal to or greater than the second operation amount (Pi2)); In the state selected in (N2), until the discharge pressure of the hydraulic pump reaches the first predetermined pressure (P0), the rotational speed of the prime mover is not changed regardless of the discharge pressure of the hydraulic pump. The output of the hydraulic pump is maintained between the first predetermined pressure (P0) and the second predetermined pressure (P1) which is higher than the first predetermined pressure. Is the output when E is the first rotational speed (N1) (E ), And when the discharge pressure of the hydraulic pump becomes equal to or higher than the second predetermined pressure (P1), the pressure of the prime mover is controlled regardless of the discharge pressure of the hydraulic pump. The rotational speed is changed from the second rotational speed (N2) to the first rotational speed (N1), and is maintained at the changed first rotational speed (N1) .

  In the present invention configured as described above, when the specific operation means is operated with an operation amount equal to or less than the first operation amount during the combined operation of the specific actuator and another actuator, the motor rotation speed control means causes the motor rotation speed to be kept constant. It is controlled to the first rotation speed of the eye. As a result, it is possible to perform work by a combined operation of the specific actuator and another actuator. Further, when the specific operation means is operated with an operation amount equal to or larger than the second operation amount larger than the above-mentioned first operation amount when the specific actuator is operated alone, a constant higher than the above-mentioned first rotation speed is set by the motor rotation speed control means. It is controlled at the second rotational speed. As a result, the specific actuator can be operated independently at a high operating speed.

  Further, for example, the operation amount of the specific operation means is increased from the state in which the operation amount of the specific operation means is set to an operation amount equal to or less than the first operation amount and the motor speed is controlled to a constant lower first rotation speed. Thus, when the rotational speed of the prime mover is shifted to a constant high second rotational speed, the rotational speed of the prime mover gradually increases as the operation amount of the specific operation means increases by the prime mover rotational speed control means. Since it is controlled, the rotational speed of the prime mover can be smoothly shifted from the first rotational speed to the second rotational speed. In the case of shifting from the high second rotation speed to the lower first rotation speed, it is possible to smoothly shift similarly.

  Further, the present invention is the above invention, wherein the hydraulic construction machine comprises a battery-driven hydraulic excavator, the prime mover comprises a hydraulic pump electric motor, and comprises a battery capable of supplying electric power for driving the hydraulic pump electric motor, The specific actuator includes a right travel motor and a left travel motor, the other actuator includes an actuator that drives a front work machine, and the specific operation means includes an operation device that operates the right travel motor and the left travel motor. It is characterized by comprising an operating device for operation.

  In the present invention configured as described above, when the operation device is operated with an operation amount equal to or less than the first operation amount during work such as excavation work by a combined operation of the right travel motor, the left travel motor, and the actuator that drives the front work machine. The prime mover rotational speed control means controls the rotational speed of the prime mover to a lower fixed first rotational speed. As a result, excavation work by a combined operation of the right travel motor, the left travel motor, and the actuator that drives the front work machine can be performed. Further, when the operating device is operated with a second operation amount larger than the first operation amount at the time of traveling independent operation by driving the right traveling motor and the left traveling motor, the engine rotational speed control means controls the number of rotations of the motor. It is controlled to a constant second rotational speed higher than one rotational speed. As a result, traveling alone operation at a high operating speed is possible. The prime mover only needs to have an output at a constant low first rotation speed, and therefore a prime mover with a relatively small output can be provided. That is, it is possible to realize both the operation by the combined operation of the right traveling motor, the left traveling motor, and the actuator that drives the front working machine and the traveling single operation at a high operating speed by providing a relatively small output prime mover. it can.

  According to the present invention, it is possible to realize both a work by a combined operation of a specific actuator and another actuator and a single operation of the specific actuator at a high operating speed by providing a relatively small output prime mover. Therefore, it is possible to realize a reduction in equipment cost by reducing the size of the prime mover.

  The best mode for carrying out the hydraulic construction machine according to the present invention will be described below with reference to the drawings.

1-4 is a figure which shows the reference example of embodiment of the hydraulic construction machine which concerns on this invention, FIG. 1 is a side view which shows the battery-driven hydraulic shovel which shows the reference example of the hydraulic construction machine which concerns on this invention, 2 is a block diagram illustrating a control system provided in a battery-driven hydraulic excavator according to a reference example of the hydraulic construction machine illustrated in FIG. 1, and FIG. 3 is a travel set in a controller included in the control system illustrated in FIG. It is a figure which shows the relationship between lever input and the rotation speed of a hydraulic pump electric motor. FIG. 4 is a diagram showing parameters relating to power acting on a hydraulic pump electric motor provided in a battery-driven hydraulic excavator according to a reference example of the present invention . FIG. 4A is a pump discharge pressure set in a controller. The figure which shows the relationship between (P) and the rotation speed (N) of the electric motor for hydraulic pumps, (b) The figure shows the relationship between the pump discharge pressure (P) and the flow rate (Q) obtained in this reference example , and this reference characteristic diagram showing the relationship of the resulting pump discharge pressure (P) and押退only volume (q) in the example, and (c) drawing the pump discharge pressure obtained in the present reference example (P) and the pump absorption torque (T) And a relationship between the pump discharge pressure (P) and the output (E), that is, the absorption horsepower of the hydraulic pump, obtained in this reference example .

As shown in FIG. 1, a battery-driven hydraulic excavator according to a reference example of the present invention includes a traveling body 10, and this traveling body 10 includes a pair of left and right crawlers 11, a crawler frame 12, and each crawler 11 independently. And a pair of traveling hydraulic motors that are driven and controlled, that is, a right traveling motor 13 and a left traveling motor 14, and a speed reduction mechanism (not shown) of these traveling motors 13 and 14. The right traveling motor 13 and the left traveling motor 14 described above constitute, for example, a specific actuator among a plurality of actuators.

  The revolving body 20 is disposed on the traveling body 10, and the revolving body 20 is provided on the revolving frame 21, the hydraulic pump electric motor 22 that constitutes the prime mover, and the hydraulic pump. It includes a battery 23 that supplies electric power to the electric motor 22, a turning electric motor 24 that is driven by electric power from the battery 23, and a reduction mechanism that decelerates the rotation of the electric turning motor 24. A turning mechanism 25 for turning the turning body 20 with respect to the traveling body 10 is provided.

  A front working machine 30 is attached to the revolving unit 20. The front work machine 30 includes a boom 31 that can be raised and lowered, a boom cylinder 32 that drives the boom 31, an arm 33 that is rotatably supported near the tip of the boom 31, and an arm that drives the arm 33. A cylinder 34, a bucket 35 pivotally supported at the tip of the arm 33, a bucket cylinder 36 for driving the bucket 35, and the like are provided. The boom cylinder 32, the arm cylinder 34, and the bucket cylinder 36 described above constitute, for example, another actuator different from the specific actuator among the plurality of actuators.

  Further, on the swing frame 21 of the swing body 20, a hydraulic pump 41 driven by a prime mover, that is, a hydraulic pump electric motor 22, and the right travel motor 13, the left travel motor 14, the boom cylinder 32, the arm from the hydraulic pump 41 described above. A hydraulic control mechanism including a hydraulic control valve 42 for controlling the direction and flow rate of the pressure oil supplied to the cylinder 34 and the bucket cylinder 36 is mounted. The hydraulic control valve 42 includes a plurality of control valves corresponding to each actuator.

A battery-driven hydraulic excavator according to a reference example of the present invention includes the control system shown in FIG. In this figure, a thick line indicates a mechanical drive system, a middle line indicates a hydraulic drive system, a thin line indicates an electrical drive system, and a dotted line indicates an electrical signal system.

  As shown in FIG. 2, the DC power from the battery 23 is converted into AC power having a predetermined voltage and frequency by the hydraulic pump inverter 52 and input to the hydraulic pump motor 22. The driving force of the hydraulic pump electric motor 22 is transmitted to the hydraulic pump 41. The hydraulic control valve 42 controls the discharge amount and the discharge direction of the operating oil to the boom cylinder 32, the arm cylinder 34, the bucket cylinder 36, the right traveling motor 13, and the left traveling motor 14 in accordance with an operation command from the operation device 54. To do. The operation device 54 includes a plurality of specific operation means for operating the right travel motor 13 and the left travel motor 14 which are specific actuators, and other actuator operation means for operating the boom cylinder 32, the arm cylinder 34, and the bucket cylinder 36. Operating means, that is, a plurality of operating devices.

  Further, the DC power from the battery 23 is converted into AC power having a predetermined voltage and frequency by the turning inverter 28 and input to the turning motor 24. Further, for example, the turning electric motor 24 is used in the generator characteristics at the time of deceleration, and the electric power regenerated by the turning electric motor 24 is converted into direct current and stored in the battery 24.

  An operation signal from the operation device 54 is input to the controller 55, and a drive command corresponding to the arithmetic processing executed by the controller 55 is given to the turning inverter 28 and the hydraulic pump inverter 52.

The controller 55 is provided with prime mover rotation speed control means which is a feature of this reference example . This prime mover rotation speed control means includes the travel lever input shown in FIG. 3, that is, the setting relationship between the operation amount (Pi) of the travel operation device and the rotation speed (N) of the hydraulic pump motor, and (a ) It is constituted by the set relationship between the pump discharge pressure (P) and the rotational speed (N) of the hydraulic pump motor shown in the figure.

  That is, the prime mover rotation speed control means is the prime mover, that is, the hydraulic pressure when the specific operation means, that is, the travel lever input of the operation device of the travel motors 13 and 14, that is, the operation amount (Pi) is less than or equal to the first operation amount Pi1 shown in FIG. The rotational speed (N) of the pump electric motor 22 is slightly lower to enable combined operation of the traveling motors 13 and 14 that are specific actuators and the boom cylinder 32, arm cylinder 34, and bucket cylinder 36 that are other actuators. When the operation amount (Pi) of the travel lever is equal to or greater than the second operation amount Pi2 that is larger than the first operation amount Pi1, the rotation speed (N) of the hydraulic pump motor 22 is controlled. Is controlled to a constant second rotational speed (N2) higher than the first rotational speed (N1), and the operation amount (Pi) of the travel lever is larger than the first operational amount Pi1. When the operation amount is smaller than the second operation amount Pi2, it gradually increases, for example, proportionally between the first rotation speed (N1) and the second rotation speed (N2) as the operation amount of the travel lever increases. Thus, it consists of what controls the rotation speed (N) of the electric motor 22 for hydraulic pumps.

  Further, as shown in FIG. 4 (a), the prime mover rotational speed control means is provided with the first rotational speed (N1) or the second rotational speed (in accordance with the input of the travel lever of FIG. 3, ie, the operation amount Pi. In a state where N2) is selected, the selected first rotational speed (N1) or second rotational speed (N2) regardless of the magnitude of the discharge pressure (P) of the hydraulic pump 41. Is configured to hold.

In the reference example configured as described above, as shown in FIG. 4B, the displacement volume (q) with respect to the discharge pressure (P) of the hydraulic pump 41 is equal to the rotational speed of the hydraulic pump motor 22 described above. Both the displacement volume q1 at the first rotation speed N1 and the displacement volume q2 at the second rotation speed N2 are controlled so that the torque is constant when the pump discharge pressure (P) is equal to or higher than the predetermined pressure P1. Is done. That is,
P × q (q1 = q2) = constant (1)
It is. The discharge flow rate (Q) of the hydraulic pump 41 is
Q = q × N (2)
Therefore, regardless of the discharge pressure (P) of the hydraulic pump 41, at the above-mentioned first rotational speed N1,
Q1 = q1 × N1 (3)
In addition, in the case of the second rotation speed N2 described above,
Q2 = q2 × N2 = Q1 × N2 / N1 (4)
Are in a relationship.

  When the rotation speed (N) of the hydraulic pump motor 22 is maintained at the second rotation speed (N2) as shown in FIG. 4 (a), it is determined whether the discharge pressure (P) of the hydraulic pump 41 varies. Regardless, N1 <N2 is a constant value.

FIG. 4C shows the torque (T) with respect to the discharge pressure (P) of the hydraulic pump 41 and the output (E), that is, the pump absorption horsepower. The torque (T) at the first rotation speed N1 is shown. When T1, the output (E) is E1, the torque (T) at the second rotation speed N2 is T2, and the output (E) is E2,
T∝P × q (q1 = q2) (5)
E = P × Q (6)
Therefore, regardless of the discharge pressure (P) of the hydraulic pump 41,
T1 = T2 (7)
E1 = P × Q1 (8)
E2 = P × Q2 = E1 × Q2 / Q1 = E1 × N2 / N1 (9)
Are in a relationship.

In the reference example described above, the operation device 54 shown in FIG. 2 is included in excavation work or the like by a combined operation of the right travel motor 13, the left travel motor 14 and an actuator such as a boom cylinder 32 that drives the front work machine 30. When the travel levers of the operating devices for the right travel motor 13 and the left travel motor 14 are operated with an operation amount equal to or less than the first operation amount Pi1 shown in FIG. 3, the engine speed control means included in the controller 55, that is, FIG. According to the setting relationship shown in FIG. 3, the rotational speed (N) of the hydraulic pump electric motor 22 is controlled to a lower constant first rotational speed (N1). Accordingly, long-time energy-saving excavation work and the like can be performed by a combined operation of the right travel motor 13 and the left travel motor 14 and an actuator such as a boom cylinder 32 that drives the front work machine 30. In addition, when the single traveling operation is performed by driving the right traveling motor 13 and the left traveling motor 14, the operating devices for the right traveling motor 13 and the left traveling motor 14 are operated at a second operation amount Pi2 or more that is larger than the first operation amount Pi1. Then, the rotational speed (N) of the hydraulic pump motor 22 is controlled to a constant second rotational speed (N2) higher than the first rotational speed (N1) by the prime mover rotational speed control means included in the controller 55. The As a result, it is possible to perform a traveling single operation at a low operating speed with a low frequency.

  For example, the operation amount of the operating device of the right travel motor 13 and the left travel motor 14 is set to an operation amount equal to or less than the first operation amount Pi1, and the rotation speed (N) of the hydraulic pump electric motor 22 is set to a constant low first rotation. When the operation amount of the above-described operation device is increased from the state where the number (N1) is controlled, and the rotational speed (N) of the hydraulic pump motor 22 is shifted to a constant high rotational speed (N2), the control is performed. 3 so that the rotational speed (N) of the hydraulic pump motor 22 gradually increases with an increase in the operation amount of the operating device, by the motor speed control means included in the device 55, that is, according to the setting relationship shown in FIG. Since it is controlled, the rotational speed (N) of the hydraulic pump electric motor 22 can be smoothly shifted from the first rotational speed (N1) to the second rotational speed (N2). Similarly, when shifting from the second rotational speed (N2) to the first rotational speed (N1), the transition can be made smoothly.

As described above, according to the reference example , the relatively small output prime mover, that is, the hydraulic pump motor 22 can be provided, and the prime mover rotational speed control means included in the controller 55 allows the right travel motor 13 that is a specific actuator. , Both long-term energy-saving excavation work by a combined operation of the left travel motor 14 and an actuator such as the boom cylinder 32 of the front work machine 30 which is another actuator, and a single travel operation at a low and fast operating speed. Can be realized.

  In addition, the prime mover rotation speed control means included in the controller 55 can smoothly shift the rotation speed between the first rotation speed (N1) and the second rotation speed (N2). The operability of the actuator can be realized.

FIG. 5 is a diagram showing parameters relating to power acting on the hydraulic pump electric motor provided in the battery-driven hydraulic excavator according to the embodiment of the present invention. FIG. 5A is a pump discharge pressure set in the controller. (P) and shows the relationship between the rotation speed of the electric motor hydraulic pump (N) FIG, (b) drawing the relationship between the pump discharge pressure obtained in this embodiment (P) and flow rate (Q), and the present The characteristic figure which shows the relationship between the pump discharge pressure (P) and displacement volume (q) which are obtained by a form , (c) A figure is the pump discharge pressure (P) and pump absorption torque (T) which are obtained by this embodiment . And a relationship between the pump discharge pressure (P) obtained in this embodiment and the output (E), that is, the absorption horsepower of the hydraulic pump.

In this embodiment, the engine speed control means provided in the controller 55 is configured so that the absorption horsepower, that is, the output (E) of the hydraulic pump 41 does not exceed the maximum absorption horsepower at the first rotation speed (N1). It consists of what can control the rotation speed (N) of the motor 22 for a motor. That is, the prime mover rotation speed control means of this embodiment has a setting relationship between the travel lever input, that is, the operation amount (Pi) and the rotation speed (N) of the hydraulic pump motor 41 shown in FIG. 3, and (a) of FIG. The pump discharge pressure (P) and the rotational speed (N) of the hydraulic pump motor 22 shown in FIG. Other configurations are the same as those in the reference example described above.

In this embodiment , the motor speed control means has the setting relationship shown in FIG. 3, that is, the setting relationship shown in FIG. 3 equivalent to that in the reference example , as shown in FIG. 5 (a). In the state where the first rotational speed (N1) is selected in accordance with the input of the travel lever in FIG. 3, that is, the first operation amount Pi1 or less, how much the discharge pressure (P) of the hydraulic pump 41 varies. Regardless, the selected first rotational speed (N1) is maintained. Further, in the state where the second rotation speed (N2) is selected in accordance with the input of the travel lever in FIG. 3, that is, the second operation amount Pi2 or more, the discharge pressure (P) of the hydraulic pump 41 is the predetermined pressure described above. Until the predetermined pressure P0 (first predetermined pressure) smaller than P1 (second predetermined pressure) is reached, the selected second rotation speed (N2) regardless of the magnitude of the discharge pressure (P) of the hydraulic pump 41. ) And the rotational speed (N) is controlled so that the pump output (E) becomes E1 when the discharge pressure (P) of the hydraulic pump 41 is between the above-described discharge pressures P0 to P1, and the discharge of the hydraulic pump 41 When the pressure (P) becomes equal to or higher than the predetermined pressure P1, the second rotation speed (N2) is changed to the first rotation speed (N1) regardless of the magnitude of the discharge pressure (P) of the hydraulic pump 41. The rotation speed (N) is changed, and the changed first rotation speed (N1) is held. It is configured.

In the embodiment of the present invention configured as described above, when the discharge pressure (P) of the hydraulic pump 41 becomes equal to or higher than the predetermined pressure P1, the hydraulic pump motor 22 outputs the output E1 at the first rotational speed N1, and the first This is an electric motor having an output characteristic corresponding to the output E1 at the first rotational speed N1 because the output characteristic corresponding to the product of the ratio (N2 / N1) of the first rotational speed N1 and the second rotational speed N2 is N2 = N1. I need it. Therefore, the hydraulic pump electric motor 22 can be a small electric motor, and the equipment cost can be further reduced.

In addition, each operation | movement according to the operation amount of the operating device of the right traveling motor 13 in this embodiment and the left traveling motor 14 is equivalent to the thing in the reference example mentioned above.

It is a side view which shows the battery drive type hydraulic shovel which shows the reference example of the hydraulic construction machine which concerns on this invention. It is a block diagram which shows the control system with which the battery drive type hydraulic excavator which concerns on the reference example of the hydraulic construction machine shown in FIG. It is a figure which shows the relationship between the travel lever input set to the controller contained in the control system shown in FIG. 2, and the rotation speed of a hydraulic pump electric motor. It is the figure which showed each parameter regarding the power which acts on the electric motor for hydraulic pumps with which the battery drive type hydraulic shovel which concerns on the reference example of this invention is equipped, (a) A figure is pump discharge pressure (P) set to a controller and shows the relationship between the rotation speed of the electric motor hydraulic pump (N) FIG, (b) drawing the relationship of the pump discharge pressure obtained in the reference example and (P) and flow rate (Q), and obtained in the reference example (C) is a characteristic diagram showing the relationship between the pump discharge pressure (P) and displacement volume (q), (c) the relationship between the pump discharge pressure (P) and the pump absorption torque (T) obtained in this reference example , It is a characteristic diagram showing the relationship between the pump discharge pressure (P) and the output (E), that is, the absorption horsepower of the hydraulic pump obtained in this reference example . BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed each parameter regarding the power which acts on the electric motor for hydraulic pumps with which the battery drive type hydraulic shovel which concerns on embodiment of this invention is equipped, (a) A figure is pump discharge pressure (P) set to a controller. The figure which shows the relationship between the rotation speed (N) of the motor for hydraulic pumps, and (b) The figure shows the relationship between the pump discharge pressure (P) and the flow rate (Q) obtained in this embodiment , and this another embodiment (C) is a characteristic diagram showing the relationship between the pump discharge pressure (P) and displacement volume (q) obtained in step (c), and shows the relationship between the pump discharge pressure (P) and pump absorption torque (T) obtained in this embodiment . It is a characteristic view which shows the relationship and the relationship between the pump discharge pressure (P) and output (E) which are obtained by this embodiment , ie, the absorption horsepower of a hydraulic pump.

10 traveling body 13 right traveling motor (specific actuator)
14 Left travel motor (specific actuator)
20 Revolving body 22 Electric motor for hydraulic pump (motor)
23 Battery 30 Front working machine 31 Boom 32 Boom cylinder (other actuator)
33 Arm 34 Arm cylinder (other actuators)
35 Bucket 36 Bucket cylinder (other actuator)
DESCRIPTION OF SYMBOLS 40 Hydraulic control mechanism 41 Hydraulic pump 42 Hydraulic control valve 52 Hydraulic pump inverter 54 Operating device 55 Controller (motor speed control means)

Claims (2)

A plurality of actuators including a prime mover, a hydraulic pump driven by the prime mover, a specific actuator driven by pressure oil discharged from the hydraulic pump, and another actuator different from the specific actuator, and the specific actuator In a hydraulic construction machine with a specific operating means to operate,
When the operation amount of the specific operation means is less than or equal to the first operation amount, the rotational speed of the prime mover is controlled to a constant first rotation speed that enables a combined operation of the specific actuator and the other actuator, When the operation amount of the operation means is equal to or greater than the second operation amount that is larger than the first operation amount, the rotation speed of the prime mover is controlled to a constant second rotation speed that is higher than the first rotation speed, and the specific operation means When the operation amount is larger than the first operation amount and smaller than the second operation amount, the operation amount of the specific operation means is increased between the first rotation speed and the second rotation speed. Motor speed control means for controlling the speed of the prime mover so as to gradually increase,
In a state where the rotation speed of the prime mover is selected as the second rotation speed in response to the operation amount of the specific operation means being equal to or greater than the second operation volume, the discharge pressure of the hydraulic pump is the first. Until the predetermined pressure is reached, the rotation speed of the prime mover is maintained at the second rotation speed regardless of the discharge pressure of the hydraulic pump, and the discharge pressure of the hydraulic pump is changed from the first predetermined pressure to the first predetermined pressure. The rotational speed of the prime mover is controlled so that the output of the hydraulic pump is the output at the first rotational speed up to a second predetermined pressure that is greater than the pressure, and the discharge pressure of the hydraulic pump is When the pressure exceeds a predetermined pressure, the rotational speed of the prime mover is changed from the second rotational speed to the first rotational speed regardless of the discharge pressure of the hydraulic pump, and the changed first rotational speed. hydraulic pressure, characterized in that so as to be held in Construction machinery. In the invention of claim 1,
The hydraulic construction machine comprises a battery-driven hydraulic excavator;
The prime mover comprises a hydraulic pump motor;
A battery capable of supplying electric power for driving the electric motor for the hydraulic pump is provided.
The specific actuator comprises a right travel motor and a left travel motor,
The other actuator comprises an actuator that drives a front work machine,
The hydraulic construction machine, wherein the specific operation means includes an operation device for operating the right travel motor and an operation device for operating the left travel motor.

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