The characteristic of this double acting hydraulic cylinder is that the piston and the rod body are integrated, the piston cross-sectional area of the left cavity is S1, the piston cross-sectional area of the right cavity is S2, and the cross-sectional area of the rod body is S3. The relationship between the three is S1=S2+ S3.
The thrust, tension, extension and contraction sp eed of basic hydraulic power cylinder have the following relationship.
Conditions: P and Q remain unchanged; F thrust=PS1, F tension=PS2=P (S1-S3), V extension=Q/S1, V contraction=Q/S2=Q/(S1-S3); because S1> S2, so F thrust>F tension, V extension<V contraction.
This kind of double acting hydraulic cylinder has a simple structure, and is mostly used in occasions with high requirement on thrust, low requirement on tension, slow extension and low movement speed, and fast return stroke, which means heavy load out and no-load return.
The characteristic of this hydraulic power cylinder is that the piston and the rod body are not a whole body, and can move on the rod body. The cross-sectional area of the piston is S2 and the cross-sectional area of the rod is S3.
The thrust, tension, extension and contraction speed of the floating hydraulic power cylinder have the following relationships.
Conditions: P and Q remain unchanged; F thrust=PS3, F tension=PS2, V extension=Q/S3, V contraction=Q/S2; the relationship between S2 and S3 can be >, <, =, so F thrust can be>, <,=F tension, V extension can be>, <,=V contraction.
In practical applications, S3 is mostly smaller than S2, so that F thrust <F tension, V extension> V extraction, which is different from ordinary hydraulic power cylinders. The purpose of this is to make it different from the first type of hydraulic power cylinder. This kind of hydraulic power cylinder is suitable for occasions requiring high tension and low thrust.
The hydraulic power cylinder of this structure is the ordinary hydraulic power cylinder, which is the first type. The difference is that its liquid supply method is different. When it is extended, the left and right chambers supply liquid at the same time; Liquid is supplied to the right cavity.
When the differential structure is extended, there is a pressure in the hydraulic cylinder motor difference due to the different action areas on both sides. Under the action of the thrust pressure difference, the rod moves to the right and extends, and the liquid discharged from the right cavity does not flow back to the tank, but the oil from the hydraulic pump enters the left cavity together to accelerate the extension speed.
F thrust=PS1-PS2=PS3, when extending, the flow of the left cavity is the supply flow Q+the flow of the right cavity Q right=VS2, we get V=Q/S3, F thrust=PS2, V contraction=Q/S2.
Compared with the first case, the thrust has changed, but the tension has not changed. Different results can be obtained by changing the area ratio of S1, S2, and S3. This structural form has been widely used in production, and only a differential valve needs to be added.