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Hydraulic drive device of electric hydraulic machinery

A technology for working machines and driving devices, applied in fluid pressure actuating devices, mechanical equipment, servo meter circuits, etc. The effect of reducing heat generation, ensuring comfort, and reducing power consumption

Active Publication Date: 2015-05-13
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 drive device of electric hydraulic machinery
  • Hydraulic drive device of electric hydraulic machinery
  • Hydraulic drive device of electric hydraulic machinery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] ~compose~

[0047] figure 1 It is a figure which shows the structure of the hydraulic drive apparatus of the electric hydraulic 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 type 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 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...; via the pilot oil passage 31 and the pilot pump 30 is connected to a pilot hydraulic pressure source 38 that generates a pilot primary pressure based on the discharge o...

Embodiment 2

[0162] Figure 7 It is a figure which shows the structure of the hydraulic drive apparatus of the electric hydraulic working machine which concerns on 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 type hydraulic excavator.

[0163] ~compose~

[0164] exist Figure 7 Among them, the hydraulic drive device of this embodiment is the same as figure 1 Unlike the first embodiment shown, the main pump 2A is of a fixed displacement 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 controller) that simulates the horsepower control of the main pump 2A in addition to the control function that simulates the cut-off control of the main pump 2A.

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

[0166] ...

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Abstract

In addition to performing load-sensing control of a main pump (2) by rotational frequency control of an electric motor (1) using a controller (50), cutoff control for controlling the rotational frequency of the main pump (2) is performed so as to reduce the discharge flow rate of the main pump (2) when the discharge pressure of the main pump (2) rises above a first specified pressure (Ppso) near the set pressure (Pmax) of a main relief valve (14). As a result, in the electric hydraulic machinery, which drives the hydraulic pump using the electric motor to drive an actuator and performs load-sensing control by rotational frequency control of the electric motor, wasted power consumption by the operation of the relief value is limited, sudden elevations in electric motor rotational frequency are limited, and higher efficiency and comfort can be secured.

Description

technical field [0001] The present invention relates to a hydraulic drive device for an electric hydraulic working machine such as a hydraulic excavator, which drives a hydraulic pump by an electric motor to drive an actuator to perform various operations, and more particularly, to a hydraulic pump such that the discharge pressure of the hydraulic pump is higher than the maximum load pressure by a fixed pressure. It is 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 electric hydraulic work machines such as hydraulic excavators that perform various operations by driving a hydraulic pump by an electric motor and driving an actuator. The electric hydraulic working machine of Patent Document 1 is configured to include a fixed-capacity hydraulic pump driven by an electric motor so that the pressure difference between the discharge pressure of the hydra...

Claims

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Application Information

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Patent Type & Authority Applications(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