JPH03128754U - - Google Patents
Info
- Publication number
- JPH03128754U JPH03128754U JP10654390U JP10654390U JPH03128754U JP H03128754 U JPH03128754 U JP H03128754U JP 10654390 U JP10654390 U JP 10654390U JP 10654390 U JP10654390 U JP 10654390U JP H03128754 U JPH03128754 U JP H03128754U
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- pilot
- hydraulic excavator
- valve
- port
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000010586 diagram Methods 0.000 description 3
Landscapes
- Operation Control Of Excavators (AREA)
Description
第1図は上部旋回式油圧掘削機の正面図、第2
図は前面図、第3図はその油圧回路図の従来例を
示す線図的構成説明図、第4図は本考案の実施例
を示す油圧回路図である。
P1,P2はポンプ、5は走行モータ、5aは
正転ポート、5bは逆転ポート、8,9は吐出路
、17,18は可変リリーフ弁、24はパイロツ
ト弁、25,26は管路。
Figure 1 is a front view of the upper swing type hydraulic excavator, Figure 2
The figure is a front view, FIG. 3 is a diagrammatic configuration explanatory diagram showing a conventional example of the hydraulic circuit diagram, and FIG. 4 is a hydraulic circuit diagram showing an embodiment of the present invention. P 1 and P 2 are pumps, 5 is a travel motor, 5a is a forward rotation port, 5b is a reverse rotation port, 8 and 9 are discharge passages, 17 and 18 are variable relief valves, 24 is a pilot valve, and 25 and 26 are pipelines. .
Claims (1)
1の操作弁を経て油圧掘削機のシリンダに供給し
、第2の操作弁で走行モータ5の正転ポート5a
、逆転ポート5bに供給するようにした油圧回路
において、 前記吐出路8,9に、パイロツト圧力が作用し
ないとセツト圧力が低く、パイロツト圧力が作用
するとセツト圧力が高くなるセツト圧力可変の可
変リリーフ弁17,18を設け、 該可変リリーフ弁17,18にパイロツト圧力
を供給するパイロツト管路23を、前記走行モー
タ5の正転ポート5aに接続する管路25と逆転
ポート5bに接続する管路26の圧力差で切換え
作動して高圧側の管路25又は26に接続するパ
イロツト弁24を設けたことを特徴とする上部旋
回式油圧掘削機の油圧回路。[Claims for Utility Model Registration] The pressure oil in the discharge passages 8 and 9 of the pumps P 1 and P 2 is supplied to the cylinder of the hydraulic excavator through the first operation valve, and the second operation valve is used to supply the pressure oil to the cylinder of the hydraulic excavator. normal rotation port 5a
, in a hydraulic circuit configured to supply to the reversing port 5b, a variable relief valve with a variable set pressure in which the set pressure is low when no pilot pressure is applied to the discharge passages 8 and 9, and the set pressure is high when the pilot pressure is applied. 17, 18, a pilot line 23 for supplying pilot pressure to the variable relief valves 17, 18 is connected to the forward rotation port 5a of the travel motor 5, and a line 26 is connected to the reverse rotation port 5b. 1. A hydraulic circuit for an upper swing type hydraulic excavator, characterized in that a pilot valve 24 is provided which switches and operates based on a pressure difference between the two and connects to a high-pressure side pipe line 25 or 26.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10654390U JPH03128754U (en) | 1990-10-12 | 1990-10-12 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10654390U JPH03128754U (en) | 1990-10-12 | 1990-10-12 |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH03128754U true JPH03128754U (en) | 1991-12-25 |
Family
ID=31655273
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP10654390U Pending JPH03128754U (en) | 1990-10-12 | 1990-10-12 |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH03128754U (en) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5254876A (en) * | 1975-10-28 | 1977-05-04 | Caterpillar Tractor Co | Balance change valve for changing pressure which is held at central position by means of spring |
-
1990
- 1990-10-12 JP JP10654390U patent/JPH03128754U/ja active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5254876A (en) * | 1975-10-28 | 1977-05-04 | Caterpillar Tractor Co | Balance change valve for changing pressure which is held at central position by means of spring |
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