TWO STEP PROPORTIONAL PRESSURE REDUCING VALVE

PROBLEM TO BE SOLVED: To provide a two-step proportional pressure-reducing valve with which it is possible to achieve two-step pressure reduction from high pressure to low pressure with a single pressure-reducing valve whereas such operation conventionally is achieved using two pressure-reducing valves.SOLUTION: A two-step proportional pressure-reducing valve 8 comprises a proportional pressure-reducing valve unit 9 and a pressure-reducing valve unit 10. The proportional pressure-reducing valve unit 9 is slidably fitted into a sleeve 27 and arranged coaxially with an electromagnetic valve 13, and has a spool 41 for forming a large diameter sectional area engaged with a tank port 26 and a small diameter sectional area smaller than the large diameter sectional area and formed between first and second discharge ports 24, 25. The pressure-reducing valve unit 10 has an oil passage 57 communicating with a small diameter hole 51 formed in a large diameter hole 56 of a stepped piston 54 fitted into the sleeve 27. One end of the stepped piston 54 is fluid-tightly sealed by a plug 58 that is screwed into the sleeve 27.SELECTED DRAWING: Figure 1 【課題】２台の減圧弁を使用して行っていた高圧から低圧への二段減圧を１台の減圧弁で行えることができる二段減圧比例弁を提供。【解決手段】二段比例減圧弁８は、比例減圧弁部９と減圧弁部１０よりなる。比例減圧弁部９はスリーブ２７に摺動自在に嵌挿し電磁弁１３と同軸上に配置され、タンクポート２６に係合する大径部の断面積と、第一、第二の吐出ポート２４，２５間に形成され大径部の断面積よりも小さい小径部の断面積とを形成するスプール４１とを有する。減圧弁部１０は、スリーブ２７に嵌挿した段付ピストン５４の大径部５６には小径孔部５１に連通する油路５７が形成されている。スリーブ２７に螺着された栓５８により、段付ピストン５４の一端を液密に封止する。【選択図】図１