cylinder mountings

CYLINDER MOUNTINGS

1. Why Cylinder Mountings?

• The hydraulic cylinders are to be mounted properly depending upon their applications for which they are designed. Improper mounting can cause side loading, which destroys rod bearings and seals, or loosens hydraulic connections to cause leaks. In the worst cases, it can even cause pistons to bind or rods to buckle.

• Some of the factors to be considered while selecting a particular mounting are nature of applications, type of force applied (tensile/compressive/bucking load), alignment of the rod with the resistive load, space constraints, etc.

2. Types of Cylinder Mountings (Methods of Cylinder Mountings)

In order to accommodate a wide variety of applications, there are different type of cylinder mountings are available. Five important types of mountings normally used in industries are depicted in Fig.5.9.

1. Foot mounting: It should be designed to give a limited amount of movement on one foot only to allow for thermal or load expansion. That is, the cylinder should be positively located or dowelled at one end only (Fig.5.9(a)).

2. Rod-end flange or front flange mounting: During the extend stroke, pressure in the hydraulic fluid acts on the cylinder-end cap, the force set up being transmitted to the front mounting flange through the cylinder body (Fig.5.9(b)).

3. Rear flange, back flange or head-end flange mounting: No stress is present in the cylinder owing to load on the extend stroke; only hoop stress is present. The load acts through the fluid onto the rear flange (Fig.5.9(c)).

4. Trunnion mounting: It allows angular movement. It is designed to take shear load only. Bearing should be as close to the cylinder body as possible (Fig.5.9(d)).

5. Eye or clevis mounting: There is a tendency for the cylinder to jack knife under load. Side loading of bearing must be carefully considered (Fig.5.9(e)).

3. Engine Mounting Arrangements

A typical engine mounting arrangements are illustrated in Fig.5.10.