JPH01156367U

JPH01156367U -

Info

Publication number: JPH01156367U
Application number: JP5386188U
Authority: JP
Priority date: 1988-04-21
Filing date: 1988-04-21
Publication date: 1989-10-27
Anticipated expiration: 2003-04-21
Also published as: JPH0534389Y2

Description

[Brief explanation of the drawing]

第１図は本考案によるパイロツト油圧切換弁を
含むシリンダの作動制御回路を示す回路図、第２
図は第１図に示したパイロツト油圧切換弁の拡大
断面図、第３図は本考案による他のパイロツト油
圧切換弁を含むシリンダの作動制御回路を示す回
路図、第４図は第３図に示したパイロツト油圧切
換弁の拡大断面図である。符号の説明、１９……タンク、２１ｄ……環状
溝（他のポートに連通する通路の一部）、２１ｈ
……環状溝、２１ｊ……（第２）環状溝、２１ｋ
……連通路、２２……スプール、２６……Ｏリン
グ（シールリング）、４０……チエツク弁、５０
……油圧源、Ｂ，Ｄ，Ｆ，Ｈ……ポート、Ｓ……
スプリング機構、Ｖ，Ｖａ……パイロツト油圧切
換弁。 Fig. 1 is a circuit diagram showing a cylinder operation control circuit including a pilot hydraulic switching valve according to the present invention;
The figure is an enlarged sectional view of the pilot hydraulic switching valve shown in Fig. 1, Fig. 3 is a circuit diagram showing the operation control circuit of a cylinder including another pilot hydraulic switching valve according to the present invention, and Fig. 4 is the same as that shown in Fig. 3. FIG. 3 is an enlarged sectional view of the illustrated pilot hydraulic switching valve. Explanation of symbols, 19... Tank, 21d... Annular groove (part of passage communicating with other ports), 21h
...Annular groove, 21j...(Second) annular groove, 21k
...Communication path, 22...Spool, 26...O ring (seal ring), 40...Check valve, 50
...Hydraulic source, B, D, F, H...Port, S...
Spring mechanism, V, Va...Pilot hydraulic switching valve.

Claims

[Scope of utility model registration request]

At least two sets of four ports are simultaneously communicated with and disconnected from each other by axial movement of a spool pushed against a spring by pilot oil pressure, and the side of the spool that engages with the spring A seal ring is provided at the end of the spool to prevent oil leakage around the spool.
This is a pilot hydraulic switching valve in which an annular groove communicating with a port connected to a hydraulic power source or a tank is provided adjacent to the seal ring, and a second annular groove is provided between the annular groove and the seal ring. When the annular groove is connected to a hydraulic power source or a tank through the port, the second annular groove communicates with a passage connected to the tank or the hydraulic power source through another port through a communication passage; A pilot hydraulic switching valve is provided with a check valve that allows outflow from the second annular groove and prevents backflow.