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Hydraulic drives of electric hydraulic working machines

A technology of operating machinery and driving devices, which is applied in the direction of fluid pressure actuating devices, mechanical equipment, servo meter circuits, etc., can solve the problems of shortening working time of operating machinery, damage to operator comfort, and faster battery attenuation, etc., to achieve Effects of heat generation reduction, comfort assurance, and power consumption reduction

Active Publication Date: 2017-10-10
NIHON KENKI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] However, since the hydraulic oil discharged from the relief valve has no effect, when the pressure of the hydraulic oil supply line held by the relief valve is P and the flow rate of the hydraulic oil supply line from the hydraulic oil supply line to the tank is set to Q , the power represented by P[MPa]×Q[L / min] / 60 is converted into heat or sound for consumption
In this case, the power consumption for cooling the electric motor increases, which leads to problems in that the discharge amount of the storage battery (power storage device) serving as the electric power source of the electric motor increases, the decay of the storage battery becomes faster, and the operation time of the working machine becomes shorter.
However, load-sensing control in which the pressure difference between the discharge pressure of the hydraulic pump and the maximum load pressure of each actuator is controlled to be constant is not conceived as the flow rate control. In the case of load-sensing control, it is not the same as the implementation of Patent Document 1. Example 1 Likewise, every time e.g. a hydraulic cylinder reaches the end of stroke, the motor speed ramps up sharply to maximum speed, with the risk of compromising the comfort of the operator due to the uncomfortable noise / vibration produced with the sharp rise in motor speed question

Method used

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  • Hydraulic drives of electric hydraulic working machines
  • Hydraulic drives of electric hydraulic working machines
  • Hydraulic drives of electric hydraulic working machines

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] ~ Composition ~

[0047] figure 1 It is a figure which shows the structure of the hydraulic drive system of the electrohydraulic working machine which concerns on 1st Embodiment of this invention. This embodiment is a case where the present invention is applied to a hydraulic drive device of a front swing hydraulic excavator.

[0048] exist figure 1 Among them, the hydraulic drive device of the present embodiment includes: an electric motor 1; a variable displacement hydraulic pump (hereinafter referred to as a main pump) 2 as a main pump driven by the electric motor 1; and a fixed displacement pilot pump 30; A plurality of actuators 3a, 3b, 3c... driven by the hydraulic oil discharged from the main pump 2; a control valve 4 located between the main pump 2 and the plurality of actuators 3a, 3b, 3c; 30 is connected to a pilot hydraulic source 38 that generates a pilot primary pressure based on the discharge oil of the pilot pump 30 ;

[0049] The control valve 4 has:...

Embodiment 2

[0162] Figure 7 It is a figure which shows the structure of the hydraulic drive system of the electrohydraulic working machine which concerns on the 2nd Embodiment of this invention. This embodiment is also a case where the present invention is applied to a hydraulic drive device of a front-swing hydraulic excavator.

[0163] ~ Composition ~

[0164] exist Figure 7 In this embodiment, the hydraulic drive device and figure 1 Unlike the first embodiment shown, the main pump 2A is a fixed capacity type, and the main pump 2A does not have the torque control device 17 for horsepower control. On the other hand, the controller 50A has a control function (function of a torque control device) simulating horsepower control of the main pump 2A in addition to a control function simulating the shutoff control of the main pump 2A.

[0165] Figure 8 It is a functional block diagram showing the processing contents of the controller 50A.

[0166] Controller 50A instead of figure 2 T...

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Abstract

A hydraulic drive device for an electrohydraulic working machine, which uses a controller (50) to control the load of a main pump (2) through the rotation speed control of an electric motor (1), and performs when the discharge pressure of the main pump (2) rises. Cutoff control of the rotation speed of the main pump (2) is controlled so as to reduce the discharge flow rate of the main pump (2) when the first predetermined pressure Ppso close to the set pressure Pmax of the main relief valve (14) is exceeded. Thus, in an electrohydraulic working machine in which a hydraulic pump is driven by an electric motor, an actuator is driven, and load-sensing control is performed by controlling the rotational speed of the electric motor, unnecessary power consumption due to the operation of the relief valve can be suppressed, and a decrease in the rotational speed of the electric motor can be suppressed. Rising sharply, ensuring comfort with greater efficiency.

Description

technical field [0001] The present invention relates to a hydraulic drive device for an electric hydraulic working machine such as a hydraulic excavator that drives a hydraulic pump by an electric motor to drive an actuator to perform various operations. In particular, it relates to a hydraulic drive device so that the discharge pressure of the hydraulic pump is only higher than the maximum load pressure by a fixed pressure A so-called load sensing type hydraulic drive device that controls the discharge flow rate of the hydraulic pump. Background technique [0002] Patent Documents 1 and 2 describe an electric hydraulic working machine such as a hydraulic excavator that drives a hydraulic pump by an electric motor and drives an actuator to perform various operations. The electric hydraulic working machine of Patent Document 1 is configured to have a fixed-capacity hydraulic pump driven by an electric motor so that the pressure difference between the discharge pressure of the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): F15B11/00E02F9/20E02F9/22F15B11/02
CPCE02F9/2296E02F3/325E02F9/2095E02F9/2228E02F9/2285F15B11/165F15B2211/20515F15B2211/20546F15B2211/251F15B2211/6309F15B2211/6313F15B2211/6651F15B2211/6653
Inventor 高桥究中村夏树竹林圭文森和繁
Owner NIHON KENKI CO LTD