JPH0373703U

JPH0373703U -

Info

Publication number: JPH0373703U
Application number: JP13492489U
Authority: JP
Priority date: 1989-11-22
Filing date: 1989-11-22
Publication date: 1991-07-24

Description

[Brief explanation of drawings]

第１図は本考案の１実施例を示す回路図、第２
図は従来例の回路図、第３図はエンジン回転数と
ポンプ吐出量の関係を示す特性図、第４図はエン
ジン回転数とポンプ吐出量の関係を示す特性図、
第５図はバルブストロークと２次流量の関係を示
す特性図、第６図は他の実施例を示す回路図であ
る。１……エンジン、２……ギヤボツクス、３……
旋回用油圧ポンプ、３ａ……パイロツト操作部、
３ｂ……パイロツト操作回路、４……旋回用以外
の油圧ポンプ、５……制御弁、６……旋回モータ
、７……管路、８……流量調整弁、９……可変絞
り弁、１０……スイツチ、１１……バイパス弁、
１１ａ……バイパス回路。 Figure 1 is a circuit diagram showing one embodiment of the present invention, Figure 2 is a circuit diagram showing one embodiment of the present invention.
The figure is a circuit diagram of a conventional example, FIG. 3 is a characteristic diagram showing the relationship between engine speed and pump discharge amount, and FIG. 4 is a characteristic diagram showing the relationship between engine speed and pump discharge amount.
FIG. 5 is a characteristic diagram showing the relationship between the valve stroke and the secondary flow rate, and FIG. 6 is a circuit diagram showing another embodiment. 1...Engine, 2...Gearbox, 3...
Hydraulic pump for swing, 3a...Pilot operating section,
3b...Pilot operating circuit, 4...Hydraulic pump other than for swing, 5...Control valve, 6...Swivel motor, 7...Pipe line, 8...Flow rate adjustment valve, 9...Variable throttle valve, 10 ...Switch, 11...Bypass valve,
11a... Bypass circuit.

Claims

[Claims for Utility Model Registration] 1. A pipe line 7 connecting a swing variable displacement hydraulic pump 3 driven by the engine 1 and a control valve 5 that controls the direction and flow rate of pressure oil to the swing motor 6. A variable throttle valve 9 is inserted, and a flow rate adjustment valve 8 operated by the differential pressure before and after the throttle valve 9 is inserted,
A hydraulic circuit for swinging a crane, characterized in that the pipe line 7 and a pilot operation section 3a for controlling a discharge amount of the variable displacement hydraulic pump 3 for swinging are communicated with each other. 2. The hydraulic circuit for swinging a crane or the like according to claim (1), further comprising a bypass valve 11 that can be opened and closed in parallel with the flow rate regulating valve 8.