Power Steering ! Electronic Power Steering

-

Power steering

            In heavy-duty (dump) trucks and power tractors the effort applied by the driver is inadequate to turn the wheels. In this case, a booster arrangement is incorporated in the steering system. The booster is set into operation when the steering wheel is turned. The booster then takes over and does most of the work for steering. This system called power steering uses compressed air, electrical mechanisms, and hydraulic pressure. Hydraulic pressure is used on a vast majority of power steering mechanism today.


            When the steering wheel is turned, the worm turns the sector of the worm wheel and the arm. The arm turns the road wheel by means of the drag link. If the resistance offered to turn the wheels is too high and the effort applied by the driver to the steering wheel is too weak, then the worm, like a screw in a nut will be displaced axially together with the distributor slide valve. The axial movement of the distributor slide valve in the cylinder will admit oil into the booster cylinder through the pipeline. 

            The piston in the booster cylinder will turn the road wheels via the gear rack, the toothed worm sector, arm, and drag link. At the same time, the worm sector will act upon the work and will shift it together with the distribution slide valve to its initial position and stop the piston travel in the boost cylinder. When the steering wheel is turned in the other direction, the wheels will be turned appropriately in the same sequence.

            The more the steering mechanism and wheels resist turning, the more the control valve is displaced. Hence, power assistance is always supplied in proportion to the effort needed to turn the wheels.

Electronic power steering

            Electrically assisted power steering is used in some cars. The assistance can be applied directly by an electric stepper motor integrated with the steering column, or the steering mechanism, or it can be applied indirectly with hydraulic assistance pressurized by an electric pump. EPS attached to the rack and pinion-steering-exists in Honda-City vehicles.


            Electronic power steering Improves steering feel and power-saving effectiveness and increases steering performance. It does so with control mechanisms that reduce steering effort. Nissan’s Blue Bird passenger car series uses an electronically controlled three-way power steering. This power steering is responsive to vehicle speed, providing maximum assistance as the speed rises. The driver can also select his or her own performance from three levels of assistance that make the steering effort heavy, normal, or light.

 


Comments

Post a Comment

Popular posts from this blog

Types of Flexible Coupling – Bibby Resilient Couplings

-
Image
Types of Flexible Coupling – Bibby Resilient Couplings                  Named after its Inventor Dr. James Bibby in 1917, this coupling is still one of the most sought after flexible couplings for heavy shock applications. Let us now look at the constructional features of the coupling. 1.       The Coupling consists of two flanges or hubs specifically mounted on the drive and the driven shafts respectively. These hubs contain axial grooves cut on their circumference. 2.       The two couplings are joined or held together by means of a specially designed grid spring. 3.       The total assembly is enclosed in a casing or shell filled with grease for low-speed applications or, in high-speed applications with high viscosity oil. Now let’s look at the working aspect of the coupling and how it tends to reduce vibration and prevents the build-up of resonance in the system. a.) The specially designed spring is wound up through the grooves forming a series of resilient bridges throughout the p
Read more

Safety Systems in Vehicles | Seat Belts | Air Bags

-
Image
Safety Systems in Vehicles | Seat Belts | Air Bags Seat belts                The function of the seat belts is to restrain the occupants of a vehicle in their seats when the vehicle hits an obstacle:                Three-point seat belt: In motoring history, this is the single most significant advance. All credit goes to Volvo’s Nils Bolin for devising it and to Volvo for introducing it in 1959. The three-pointer afforded unrivaled restraint. Its use was a quick, easy one-handed operation. Many improvements have been made to the webbing, mountings, latches, and inertia reels and belts have got smarter in relating to accident severity and occupant weight. In the present day vehicles, seat belts have become mandatory for the driver and front passenger. Some vehicles have seat belts for rear passengers also.                Seat belt pre-tensioner: A spring-loaded or explosive device that reacts to a severe frontal impact by automatically snugging the seat belt tight for fully effective re
Read more

What Is Nvh ???

-
Image
What Is Nvh ? Noise:                Noise is defined as an unpleasant or unexpected sound created by a vibrating object. Vibration:                Vibration is defined as any objectionable repetitive motion of an object, back-and-forth or up-and-down. Harshness:                Harshness is defined as an aggressive suspension feel or lack of “give” in response to a single input. Noise and Vibration Theory:                A vibrating object normally produces sound, and that sound may be an annoying noise. In the case where a vibrating body is the direct source of noise (such as combustion causing the engine to vibrate), the vibrating body or source is easy to find. In other cases, the vibrating body may generate a small vibration only. This small vibration may cause a larger vibration or noise due to the vibrating body’s contact with other parts. When this happens, attention focuses on where the large vibration or noise occurs while the real source often escapes notice.                 A
Read more