Automotive Components: Hand Brake System - Coursework Example

Hand Brake System An automobile comprises around 1000 nitty gritty parts that all contribute to its total functionality. In the absence of one part, the automobile is no longer functional and efficient. One of the most important aspects in automobiles is the brakes. Hand brakes in particular are added in the modern mechanisms of automobiles for safety. Auto Braking System The braking system of automobiles comprises a group of small and big mechanical, hydraulic and electric components with one goal contribution to the whole machine – that is to stop a moving automobile with the use of friction. The first braking system were those external type brakes found on horse carriages. Then internal brakes were discovered with the use of drums and discs attached to wheels. Generally, a braking system is composed of disc brakes and drum brakes. These are connected with calipers and wheel cylinders in which pistons are attached for application of friction along the surface of the walls of brake drums. The application of pressure then slows down the wheel rotation of the automobile (Motorist Assurance Program, 2014). Hand brakes are installed in automobiles as secondary braking system holding cars in position. They don’t overcome the same inertia as required by the main braking system. There is less braking power as well and lesser force to keep automobiles in stationary position (Lexus Technical Training, n.d). Hand Brakes Modern braking systems have been upgraded from the traditional braking systems. Basically, cars have brakes on the front working on hydraulic system. Hand brakes are part of the whole braking system. Hand brakes mechanically act on the rear wheels. It consists of lever and arm in the brake drum operated with a cable from the handbrake lever in the car. The mechanical system separates from the hydraulic cylinder when acted on the shoes of the braking system. Basically, hand brakes is considered as parking brakes as they give limited braking in the absence of hydraulic breaking system (Howacarworks, 2014). The hand brake consists of two links connected to the brake shoes. When the hand is applied on the hand brakes, the brake shoes are opened and a braking action on the drums is obtained.  The wheel cylinders in brake calipers holding the wheel cylinders in place. The hand brake system is shown in this diagram: Design Parameters The brake system of automobile are designed intricately so as to achieve the maximum efficiency and functionality desired. Braking system functionality requires deceleration in controlled repeatable manner, maintain constant downhill speed, can hold vehicle on stationary on flat gradient. The design parameters for braking system comprises of the following: magnetic circuit design; material selection; working surface area, sealing; viscous torque generation; applied current density and MR fluid selection. These are configuration elements considered for design optimization of automobile brake systems (Karakoc, 2008). It is of prime importance to have the braking effort between the rear and front wheels to be appropriately proportioned. The front ones must lock up first before the rear ones. The system is fully functional when the required deceleration rate is obtained. Basically the following parameters are observed in braking systems (Krishnamacharie, 1996). Front weight Rear weight CG height CG to front Axle CG to rear Axle Wheelbase Tire Rolling Radius Cars are designed with hand brakes which are popularly lever type. There are various styles for hand brake systems. One of the styles is the service brake design. This design uses the ordinary service brake mechanism where operation includes mechanical shoe and piston. The other brake system is the parking brake. It has a lever located near the driver. The lever is pulled by hand. These levers are connected with cables to the brake assembly. Parking brakes have ratchet locking mechanism that maintains the lever at the set position. Parking brake levers are designed as one of the following: Stick Types, Center Lever Type and Pedal type ( Lexus Technical Training, n.d). Hand brakes are the most useful type of secondary brakes. They can be used in start up of engines at inclined steeps. The centrally placed handles are the easiest to be activated by drivers or the passenger. They are the preferred designs for initiation of hand brake turns since it can prevent the brake from latching when the release button is released (Motorcars, n.d) Latest Designs for Hand Brakes Hand brakes are implemented with newer designs influenced by modern technology. There are the Primitive cable pulling type and the computer controlled brakes. Cable pulling type of hand brakes has electric motor the pulls the emergency brake cable. Computer controlled units are designed in such a way that the motor is attached to the brake caliper automatically controlled via computer. These latest designs are already installed in cars such as BMW (Motorcars.in, n.d). Latest technology is producing automated hand brakes. There are push button hand brakes already available in the market today. Push buttons are mounted on the dash boards of cars that are accessible to the driver. It takes less space within the car and the installation is done easily. This type of hand brakes is fully automatic and can be switched of automatically as well (Karnataka, 2011). Automatic parking brakes are truly appreciated especially on steeps, hills and other inclined roads. It ensures smooth and gradual operation of the car with utmost safety to the driver and the passenger. The computer assisted automated hand brakes deduces the minimum amount of torque to advance vehicles. It offers no risk for cars to roll upon engine initiation. Moreover, automated hand brakes start off cars gently and smoothly since the system releases the brakes gradually. Hand brakes Manufacture and Quality Inspection Handbrakes are tailor-made in accordance with the automobile where it is installed. There are general materials used in the manufacture of hand brakes and the clutch system. Hand brake levers are made from high quality stainless steels. They have been improved through the years where fabrication includes other metals such as aluminum alloy, high tensile alloys, mild steel and other metals. They offer outstanding strength, superior design and conformable operating features. They offer corrosion resistance, rugged construction and superior finish that is compatible with the interior design of cars. The cables used for handbrakes are braided ropes building the cable which are flexible cables. Braided wires building the cables type are those cables with superior strength. Spiral rope cables are covered with nylon and molybdenum disulphide for the self lubrication of cables. A trapezoidal sheath and inner plastic pipe is also installed for good flexibility and protection of the rope when they are rubbed with metal sheaths (TRW Clutch & Handbrake Cables,2014). Handbrake productions are done in various stages such as shearing, notching, plate straightening, welding plates, planning and drilling. These are all done in fixtures to assure perfect alignment. The body sections are welded perfectly in steel plates where heavy truss rods and braces provide strength to the assembly. For easy operation of hand brake system, they are built with simple designs. The moving parts must be kept at minimum and it must be built with truss rod construction. Basically, hand brake system is designed to work in the most direct fashion (Dreiss& Krump, n.d). Handbrakes with their clutch cables undergo quality inspection before they are released in the market. A rolling road test bench is applied as tests for hand brakes. If there are dragging that occur, then the brake system is inspected deeper. The drums are removed and the hand brake levers are checked if they are working properly. If the hand brake levers are released, the shoes should get back to resting position. Disconnection and checking of cables are always done as part of quality checking of the brakes before the other parts are mounted (TRW Clutch & Handbrake Cables,2014). Testing procedures for hand brakes must be ensured that equipment is secured. According to APTA Press Task Force (1999), the following steps are done for quality inspection of handbrakes: Visual inspection of handbrakes to confirm proper clearance to the following: worn pins, gears and pawls. Full application of handbrakes. Shoe/pads are ensured if they are set firmly against the disc. In the application mode of the handbrake, all associated linkages and cables must be inspected. Thorough inspection of handbrake mechanism when fully released. Inspect of the shoes/pads are also fully released. Associated linkages such as chains, levers, pulleys, pins, clevises, bushings, cotter pins and cables are inspected to be okay as the handbrake is released. The test date of the handbrake must be marked in the handbrake to signify that it passed quality test. The advent of hand brake production has inclined into sophistication. There various materials for the assembly totally depend upon the automobile. The designs are also depending upon the assembly of the car. The braking system is never taken for granted in cars. They provide safety for the passengers and the machine as well. Hand brakes offer easy operation as drivers are assured that they can position their car intricately. Handbrakes technology is geared towards more energy efficient and automatic operation. Works Cited APTA. (1999). Standarf for Passenger Car Handbrake Periodic Inspection and Maintenance. Vol. IV- Inspection and Maintenance. Available from http://www.apta.com/resources/standards/Documents/APTA-PR-IM-S-004-98.pdf Dreis & Krump. (n.d). Profit Profiles in Hand Brakes Bulletin HB 66. USA:California. Howacarworks. (2014). How the Braking sytem works. Avaialable from http://www.howacarworks.com/basics/how-the-braking-system-works Karakoc K. et al. (2008). Design considerations for an automotive magnetorheological brake, Mechatronics . Available at file:///C:/Documents%20and%20Settings/Server/My%20 Documents/Downloads/d912f5112d52bd85fb.pdf Karnataka, B. (2011). Push Button Hand Brake. Tech Briefs. Available from http://contest.techbriefs.com/2011/entries/transportation/1269 Krishnamachari R.S. (1996). Design of a Vacuum-Assisted Hydraulic Braking System. University of Michigan. Available from http://ode.engin.umich.edu/publications/PapalambrosReports/UM-MEAM-96-12.pdf Motorcars.in. (n.d). Hand Brake or Parking Brake: Discussion Forms. Available at http://www.motorcars.in/brakes/hand_brake.htm Lexus Technical Training. (n.d). Section 6: Parking Brake. Available at http://www.autoshop101.com/forms/brake06.pdf Motorist Assurance Program. (2014). Auto Braking Systems. Available from http://motorist.org/articles/auto-braking-systems TRW Clutch & Handbrake Cables. (2014). TRW Automotives. Available at https://www.trwaftermarket.com/en/Products/Drum-Brake-and-Actuation-Systems/Handbrake--Clutch-Cables/ Read More