Chapter 21. -OTHER AUXILIARY EQUIPMENT 



SOCKET RING 



OUTPUT 

 SHAFT 



PISTON 

 (ONE OF 9) 



FIXED TILT 



VALVE PLATE 



CYLINDER BARREL 



FROM A-END 



TO A-END 



Figure 21-1.— Hydraulic motor for electrohydraulic transmission. 



110.23 



(See fig. 21-3.) the turning component rotates 

 the socket ring. The rotation of the socket ring 

 causes the cylinder barrel and output shaft of 

 the motor to rotate, and thereby provides the 

 rotary motion utilized to drive a machine. 

 When reciprocating motion is required, as 

 in the case of a steering gear (fig. 21-4), the 

 motor of an electrohydraulic transmission is 

 replaced by a piston or plunger. The com- 

 plete hydraulic assembly of which the plunger 

 is a part is commonly called a ram. The 

 force of the hydraulic fluid from the pump 

 causes the movement of the piston or plunger. 

 The tilting box in the pump can be controlled 

 either locally (as on the anchor windlass) or by 

 remote control (as on the steering gear). 



STEERING GEARS 



The steering gears installed on naval ships 

 are of two types: electromechanical and electro- 

 hydraulic. Most modern naval ships have steer- 

 ing gears of the electrohydraulic type; however, 

 electromechanical steering gears are also de- 

 scribed briefly. 



ELECTROMECHANICAL STEERING GEAR 



Electric motors were first introduced as 

 prime movers of steering gears on combatant 

 ships to serve in case of failure of the steam 

 steering engines, at one time the only prime 

 mover used. Electric motors were used later 

 as the primary source of power, with steam as 

 a reserve. Steam is no longer used as a prime 

 mover for steering gears. The use of electro- 

 mechanical steering gear is now limited to small 

 noncombatant vessels. 



The principles of operation are about the 

 same for all designs of electromechanical steer- 

 ing gear. Any differences that exist are chiefly 

 in the manner in which the driving motor is 

 connected to the tiller and the method by which 

 the motor is controlled. The motor may drive 

 the tiller by means of gears and a quadrant, a 

 right- and left-hand screw assembly (fig. 21-5), 

 or by means of wire rope from a drum. In the 

 gear and quadrant type, the steering engine is 

 located in the steering gear room; in the wire 

 rope and drum type, it may be installed in a 

 nearby machinery space. 



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