JPS5869059U

JPS5869059U - Hydraulic power shovel hydraulic control device

Info

Publication number: JPS5869059U
Application number: JP16385681U
Authority: JP
Inventors: 南部　正博
Original assignee: 株式会社日本製鋼所
Priority date: 1981-11-04
Filing date: 1981-11-04
Publication date: 1983-05-11
Also published as: JPS6332195Y2

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Brief explanation of the drawing]

第゛１図は従来の油圧パワーショベルの油圧制御装置を
示す図、第２図は本考案による油圧パワーショベルの油
圧制御装置を示す図、第３図は本考案の第２の実施例で
ある油圧制御装置を示す図である。　　　　− １・・・・・・油圧ポンプ、２・・・・・・旋回モー　
タ用切換弁、３・・・・・・走行モータ用切換弁、４・
・・・・・アームシリンダ用切換弁、５・・・・・・カ
ウンタバランス弁、５ａ・・・・・・パイロットポート
、６・・・・・・旋回モータ、７・・・・・・走行モー
タ、８・・・・・・アームシリンダ、８ａ、　　６ｂ・
・・・・・シリンダ室、９・・・・・・伸長用油路、９
′・・・・・・収縮用油路、１０・・・・・・パイロッ
ト切換弁、ｌｅａ・・・・・・オリフィス、１１・・・
・・・チェック弁、１２・・・・・・油路。〜゛−−＼Fig. 1 shows a conventional hydraulic control device for a hydraulic power shovel, Fig. 2 shows a hydraulic control device for a hydraulic power shovel according to the present invention, and Fig. 3 shows a second embodiment of the present invention. It is a figure showing a hydraulic control device. - 1...Hydraulic pump, 2...Swivel motor
switching valve for motor, 3... switching valve for travel motor, 4.
...Arm cylinder switching valve, 5...Counter balance valve, 5a...Pilot port, 6...Swivel motor, 7...Travel Motor, 8... Arm cylinder, 8a, 6b.
...Cylinder chamber, 9...Extension oil passage, 9
'... Contraction oil path, 10... Pilot switching valve, lea... Orifice, 11...
... Check valve, 12 ... Oil line. 〜゛−−＼

Claims

[Scope of Claim for Utility Model Registration] Hydraulic pressure is supplied in parallel from one hydraulic pump to the swing motor that swings the power shovel and the arm cylinder that extends and contracts the arm, respectively, through a swing motor switching valve and an arm cylinder switching valve. In the hydraulic control device for a hydraulic power excavator, the extension oil passage communicates the arm cylinder switching valve and the cylinder chamber on the side where the arm cylinder piston is extended, or the arm cylinder switching valve and the arm cylinder piston are contracted. A pilot switching valve and a check valve are installed in parallel in the contraction oil passage that communicates with the cylinder chamber on the side to be extended, and when the pilot switching valve and check valve are installed in the extension oil passage, the check valve is connected from the arm cylinder. If the valve is arranged in a direction that allows oil to flow to the arm cylinder switching valve, and if a pilot switching valve and a check valve are installed in the contraction oil passage, the check valve should be placed in the direction that allows oil to flow from the arm cylinder switching valve to the arm cylinder. The pilot switching valve is arranged in a direction that allows flow, and the pilot switching valve guides the supply pressure to the swing motor as pilot pressure, and when the pilot pressure is greater than a predetermined value, the pilot switching valve connects the arm cylinder switching valve and the arm cylinder to the orifice. For arm cylinder when connected through and the pilot pressure is lower than the specified value.
゛A hydraulic control bag for a hydraulic power excavator characterized by connecting the switching valve and the arm cylinder without going through an orifice! .