JPH0260701U

JPH0260701U -

Info

Publication number: JPH0260701U
Application number: JP14032988U
Authority: JP
Priority date: 1988-10-27
Filing date: 1988-10-27
Publication date: 1990-05-07

Description

[Brief explanation of drawings]

第１図ないし第４図は本考案の第１の実施例を
示し、第１図は油圧回路図、第２図は戻り油の流
量と出口側圧力との関係を示す特性線図、第３図
は補助切換弁の拡大縦断面図、第４図は第１図と
異なる操作状態を示す油圧回路図、第５図は第２
の実施例を示す油圧回路図、第６図は第３の実施
例を示す油圧回路図、第７図は第４の実施例を示
す油圧回路図、第８図は従来技術を示す油圧回路
図である。１……油圧ポンプ、２……タンク、４……油圧
モータ、４Ａ……容量可変部、５，４１……容量
可変アクチユエータ、８Ａ，８Ｂ……主管路、９
……方向切換弁、９Ａ……操作レバー、１０，５
１……カウンタバランス弁、１３……シヤトル弁
（高圧選択弁）、１４……制御管路、１５……ド
レン管路、１６，２２……パイロツト管路、２１
，３１……容量制御弁、２３……低圧選択弁、２
５……補助切換弁、２４，３２……パイロツト管
路。 1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a hydraulic circuit diagram, FIG. 2 is a characteristic diagram showing the relationship between return oil flow rate and outlet side pressure, and FIG. The figure is an enlarged vertical cross-sectional view of the auxiliary switching valve, Figure 4 is a hydraulic circuit diagram showing an operating state different from Figure 1, and Figure 5 is a hydraulic circuit diagram of the auxiliary switching valve.
Fig. 6 is a hydraulic circuit diagram showing the third embodiment, Fig. 7 is a hydraulic circuit diagram showing the fourth embodiment, and Fig. 8 is a hydraulic circuit diagram showing the prior art. It is. DESCRIPTION OF SYMBOLS 1... Hydraulic pump, 2... Tank, 4... Hydraulic motor, 4A... Variable capacity part, 5, 41... Variable capacity actuator, 8A, 8B... Main conduit, 9
... Directional switching valve, 9A ... Operation lever, 10,5
1... Counter balance valve, 13... Shuttle valve (high pressure selection valve), 14... Control pipe line, 15... Drain pipe line, 16, 22... Pilot pipe line, 21
, 31... Capacity control valve, 23... Low pressure selection valve, 2
5... Auxiliary switching valve, 24, 32... Pilot pipe line.

Claims

[Claims for Utility Model Registration] (1) A variable capacity hydraulic motor having a variable capacity section, a variable capacity actuator that tilts and drives the variable capacity section of the hydraulic motor between a large capacity side and a small capacity side; A pair of main pipes connecting the inlet and outlet sides of the hydraulic motor to a hydraulic pump and a tank, and a main pipe provided in the middle of the pair of main pipes to control the flow rate of pressure oil supplied to and discharged from the hydraulic motor, a directional switching valve that switches the rotational direction of the hydraulic motor; and a hydraulic motor that is located between the directional switching valve and the hydraulic motor and is disposed between the pair of main pipes, and is on the high-pressure side of each of the main pipes. a high pressure selection valve that selects an inlet side pressure and supplies it to the variable capacity actuator; and a high pressure selection valve that is located between the directional control valve and the hydraulic motor and is disposed between the pair of main pipes; A low pressure selection valve selects a hydraulic motor outlet side pressure that is a low pressure side, and when the hydraulic motor outlet side pressure selected by the low pressure selection valve is lower than a predetermined pressure, the capacity variable part of the hydraulic motor is set to a large capacity constant. and when the hydraulic motor outlet side pressure is higher than a predetermined pressure, the capacity variable part is tilted between a large capacity side and a small capacity side according to the hydraulic motor inlet side pressure derived from the high pressure selection valve. A variable capacity hydraulic motor control circuit configured to (2) A capacity control valve is provided to switch and control the pressure oil supplied to the variable capacity actuator, and the capacity control valve is controlled to control the hydraulic motor outlet side pressure from the high pressure selection valve and the hydraulic motor outlet side pressure from the low pressure selection valve. 2. A variable displacement hydraulic motor control circuit according to claim (1), which is configured to switch between a large capacity side and a small capacity side depending on the conditions.