Cushion lock assembly with shuttle and anti-cavitation checks
|C, C/S||Ports C1, C2, V1, V2: 1/2" NPTF; Port T: 3/4" NPTF; Port S: 1/4" NPTF;|
|D, D/S||Ports C1, C2, V1, V2: 3/4" NPTF; Port T: 3/4" NPTF; Port S: 1/4" NPTF;|
|K, K/S||Ports C1, C2, V1, V2: SAE 10; Port T: SAE 12; Port S: SAE 4;|
|L, L/S||Ports C1, C2, V1, V2: SAE 12; Port T: SAE 12; Port S: SAE 4;|
|V, V/S||Ports C1, C2, V1, V2: 1/2" BSPP; Port T: 3/4" BSPP; Port S: 1/4" BSPP;|
|W, W/S||Ports C1, C2, V1, V2: 3/4" BSPP; Port T: 3/4" BSPP; Port S: 1/4" BSPP;|
This valve assembly provides overrunning load-control and load-port relief protection and includes a load sense shuttle for brake release. Connecting the T port is optional and will supply make-up oil and may flush hot dirty oil out of the actuator. Oil coming out of the actuator may return to tank through either port T or the directional valve.
- The counterbalance valves should be set at 1.3 times the maximum load induced pressure.
- The term cushion in the name Cushion Lock is a misnomer. Because the counterbalance valves play a dual role as load controls and work port reliefs they must be set too high to provide any real cushion. Deceleration can only be achieved by ramping down the input flow.
- Low pilot ratio counterbalance valves (3:1 vrs 10:1) may be necessary to generate enough pressure to release a brake.
- Hydraulic motors leak. Therefore a mechanical brake is recommended to positively lock any stopped live load.
- These packages are also available as 3 letter manifolds. Look under counterbalance.
|Body Type||Line mountLine mount|
|Capacity||30 gpm120 L/min.|
|Mounting Hole Diameter||.40 in..40 in.|
|Mounting Hole Depth||ThroughThrough|
|Mounting Hole Quantity||22|
There are exactly 250 Sun drops in a cubic inch or 15 in a cc.
Reasons to anodize:
- To increase corrosion resistance. Sun uses 6061-T651 aluminum. It is one of the most corrosion resistant aluminum alloys there is. Whether or not anodizing improves the corrosion resistance of 6061 aluminum is debatable. We have yet to have a manifold returned because of corrosion.
- Appearance (color). The 2 colors that would appeal to Sun would be blue or black. Unfortunately these are the colors that are hardest to do consistently.
- To provide a hard wear surface. Sun does not make parts-in-body valves. The manifold is just plumbing. We don't need a wear surface.
- Because everyone else does it. Bad reason.
Reasons to not anodize:
- Cost. It's another process.
- Logistics. When you make tens of thousands of manifolds a month and you anodize hundreds, it's a problem. Consistency. See above.
- Stamping. After a body is anodized you cannot do any more stamping without making a mess.
Inspection. Have you ever tried to look for burrs in a black anodized body? It's the old blackboard factory at night scenario.
- Torque. You will experience an increase in breakaway torque when removing items from an anodized manifold.
- Fatigue life. This is the best reason to not anodize. Fatigue failure is a very complex phenomenon. What it takes to initiate a crack is difficult to predict. What it takes to propagate a crack is readily defined. Anodizing produces a very thin, very hard, and very brittle surface on aluminum. The first time you pressurize an anodized aluminum manifold you have initiated fatigue cracks. Whether or not the stress is enough to propagate the cracks is a matter of pressure and manifold geometry. Anodizing an aluminum manifold grossly reduces the fatigue life by anywhere from 20% to 50%.
Direct-acting valves are used to prevent over pressure, and pilot-operated valves are used to regulate pressure. If you are unsure, use a direct-acting valve. Sun's direct acting valves are very fast, dirt tolerant, stable, and robust. Sun's pilot-operated valves are moderately fast, they have a low pressure rise vs. flow curve, and they are easy to adjust.
- Important: Carefully consider the maximum system pressure. The pressure rating of the manifold is dependent on the manifold material, with the port type/size a secondary consideration. Manifolds constructed of aluminum are not rated for pressures higher than 3000 psi (210 bar), regardless of the port type/size specified.
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