比例阀对流量的控制可以分为两种： 一种是开关控制：要么全开、要么全关，流量要么最da、要么最小，没有中间状态，如普通的电磁直通阀、电磁换向阀、电液换向阀。 另一种是连续控制：阀口可以根据需要打开任意一个开度，由此控制通过流量的大小，这类阀有手动控制的，如节流阀，也有电控的，如比例阀、伺服阀。 所以使用比例阀或伺服阀的目的就是：以电控方式实现对流量的节流控制（当然经过结构上的改动也可实现压力控制等），既然是节流控制，就必然有能量损失，伺服阀和其它阀不同的是，它的能量损失更大一些，因为它需要一定的流量来维持前置级控制油路的工作伺服阀的主阀一般来说和换向阀一样是滑阀结构，只不过阀芯的换向不是靠电磁铁来推动，而是靠前置级阀输出的液压力来推动，这一点和电液换向阀比较相似，只不过电液换向阀的前置级阀是电磁换向阀，而伺服阀的前置级阀是动态特性比较好的喷嘴挡板阀或射流管阀。 也就是说，伺服阀的主阀是靠前置级阀的输出压力来控制的，而前置级阀的压力则来自于伺服阀的入口p，假如p口的压力不足，前置级阀就不能输出足够的压力来推动主阀芯动作。 而我们知道，当负载为零的时候，如果四通滑阀完全打开，p口压力=t口压力+阀口压力损失（忽略油路上的其它压力损失），如果阀口压力损失很小，t口压力又为零，那么p口的压力就不足以供给前置级阀来推动主阀芯，整个伺服阀就失效了。所以伺服阀的阀口做得偏小，即使在阀口全开的情况下，也要有一定的压力损失，来维持前置级阀的正常工作。 D41FHE02B4NB00 D41FHE02B4NB0048 D91FHE01H1NB00 D91FHE01H1NB0048 D41FHB32B1NB00 D41FHB32B1NB0048 D41FHE52C1NB00 D41FHE52C1NB0048 D41FWB32FC2NLW0 D41FWB32FC2NLW026 D31FWE01CC4NXW0 D31FWE01CC4NXW026 D31FWA32CC4NLW0 D31FWA32CC4NLW026 D41FHB61C1NB00 D41FHB61C1NB0048 D41FHE52F5VB00 D41FHE52F5VB0048 D91FHE01H4NB00 D91FHE01H4NB0048 D31FWE01CC4NLW0 D31FWE01CC4NLW026 D46FHE01F2NB00 D46FHE01F2NB0048 D81FHE02F1NB00 D81FHE02F1NB0048 D31FHB61C5NB00 D31FHB61C5NB0048 D41FHB00F4NB0048X856 D111FHB32L1NB20 D111FHB32L1NB2048 D46FHE01B5NB00 D46FHE01B5NB0048 D31FHB32A4NE00 D31FHB32A4NE0047 DK-M8X1-15 DK-M8X1-15 DIN 906 AK-WL06CKG092 AK-WL/RL06-C-K-G09-2 SK-D41FW SK-D41FW-10/20 D36FHE50B4NB00 D36FHE50B4NB0048 D91FHE01F1NE00 D91FHE01F1NE0048 D41FHE01E1NE00 D41FHE01E1NE0048 D91FHB63H2NB00 D91FHB63H2NB0048 D41FHB31E1NE00 D41FHB31E1NE0048 D41FHE01F4NE00 D41FHE01F4NE0048 D41FHB32F4NE08 D41FHB32F4NE0848 VSVS VSVS VSVS VSVS D31FWE01CC4NLW8 D31FWE01CC4NLW827 DK-M6X1-25 DK-M6X1-25 DIN 906 D91FHE02F1VB00 D91FHE02F1VB0048 SK-D81FHV SK-D81FH-V K-STAND 30-46 D91FHB32H5NB00 D91FHB32H5NB0048 D41FHE02C1NB00 D41FHE02C1NB0048 D41FWE01FC4NLW0 D41FWE01FC4NLW026 D91FWE01HC4NLW0 D91FWE01HC4NLW028 D31FSE01B4NLW0 D31FSE01B4NLW037 D41FSE01C4NLW0 D41FSE01C4NLW039 D91FSE01H4NLW0 D91FSE01H4NLW040 D111FSE01L4NLW0 D111FSE01L4NLW037 D91FHE52H4NB00 D91FHE52H4NB0048 D1FVE02BCVLB D1FVE02BCVLB35 D31FWE02CC4NLW0 D31FWE02CC4NLW026 D41FHE52E2NB00 D41FHE52E2NB0048 D91FWE01HC1NLW0 D91FWE01HC1NLW028 D41FWE02FC4NLW0 D41FWE02FC4NLW026 D91FHE02H4NB00 D91FHE02H4NB0048 D81FHE52H4NB00 D81FHE52H4NB0048 D81FSE01E4NLW0 D81FSE01E4NLW039 D41FSE02C4VXW0 D41FSE02C4VXW039 D41FTB00FC4NF0842X821 D31FWA31CC4NLW0 D31FWA31CC4NLW026 D31FWE02CC5NLW0 D31FWE02CC5NLW026 D41FHB34F2NB00 D41FHB34F2NB0048 D46FHE01F1NB00 D46FHE01F1NB0048 D41FHB61F1NB00 D41FHB61F1NB0048 D91FHE01H1NB20 D91FHE01H1NB2048 D41FSE02C1NLW0 D41FSE02C1NLW039 D31FWA32CC1NLW0 D31FWA32CC1NLW026 D41FSE01C2NXW0 D41FSE01C2NXW039 D31FSE02B4NXW0 D31FSE02B4NXW037 D41FSE02C1NXW0 D41FSE02C1NXW039 D111FSB32L2NXW0 D111FSB32L2NXW037 D41FSE02C4NXW0 D41FSE02C4NXW039 D91FSB32H2NXW0 D91FSB32H2NXW040 D91FWE05HC2NLW0 D91FWE05HC2NLW028 D41FSE02C1VXW0 D41FSE02C1VXW039 D31FWB31CC4NLW0 D31FWB31CC4NLW026 D41FSE01C5NXW8 D41FSE01C5NXW839 D41FWB31FC1NLW0 D41FWB31FC1NLW026 D111FSB34L4NXW0 D111FSB34L4NXW037 D41FHE01B2NB00 D41FHE01B2NB0048 SK-D41FHV SK-D41FH-V K-STAND 30-47 D31FWE03CC4NLW0 D31FWE03CC4NLW026 D111FSE02L2NXW0 D111FSE02L2NXW037 D46FHE01F5NB00 D46FHE01F5NB0048 D41FWB31FC2NLW0 D41FWB31FC2NLW026 D91FSB31H2NXW0 D91FSB31H2NXW040 AK-D1FVSB030 AK-D1FV-S-B0-30 D41FWE02FC2NLW0 D41FWE02FC2NLW026 D41FSB32C4NXW0 D41FSB32C4NXW039 D41FHE01E5NB08 D41FHE01E5NB0848 D36FHE01B4NB00 D36FHE01B4NB0048 AK-D1FWCJW20 AK-D1FW-C-JW-20 D31FWE02CC4VXW0 D31FWE02CC4VXW026 D41FSB32C1NXW0 D41FSB32C1NXW039 D41FWA32FC4NLW0 D41FWA32FC4NLW026 D91FWE02HC2NXW0 D91FWE02HC2NXW028 D111FSE02L1NXW0 D111FSE02L1NXW037 NC-PROFIBUS NC-PROFIBUS D31FWE03CC4NXW0 D31FWE03CC4NXW026 D31FWB32CC4NLW0 D31FWB32CC4NLW026 D31FHA32C4VB00 D31FHA32C4VB0047 D41FWE02FC2NXW0 D41FWE02FC2NXW026 D41FWB32FC2NXW0 D41FWB32FC2NXW026 D31FHB61A2NB00 D31FHB61A2NB0048 D41FSA32C2NXW0 D41FSA32C2NXW039 D91FWE01HC2NLW8 D91FWE01HC2NLW828 D41FWE01FC2NLW8 D41FWE01FC2NLW827 D81FHA32F1NB00 D81FHA32F1NB0048 D41FWE01FC4NXW0 D41FWE01FC4NXW026 D41FHB61F2VB00 D41FHB61F2VB0048 D41FHA32C2NE00 D41FHA32C2NE0048 D91FWE02HC1NXW0 D91FWE02HC1NXW028 D31FWE01CC5NXW0 D31FWE01CC5NXW026 D41FWE01FC2NLW0 D41FWE01FC2NLW026 D111FHE01L2NE00 D111FHE01L2NE0048 D41FWE02FC1VLW0 D41FWE02FC1VLW026 D31FSE01B2NXW0 D31FSE01B2NXW037 D41FWA32FC1NLW0 D41FWA32FC1NLW026 D91FSB32H1NXW0 D91FSB32H1NXW040 D81FSE02E4NXW0 D81FSE02E4NXW039 D31FSB89B4NXW0 D31FSB89B4NXW037 D31FHE02C1VB00 D31FHE02C1VB0047 D31FSB31B4NLW0 D31FSB31B4NLW037 D31FSE01B1NXW0 D31FSE01B1NXW037 D1FPE50MB9NS00 D1FPE50MB9NS0015