Functions of Steering Gear Box:
1. It converts the Rotary movement of the steering wheel in to the angular turning of the front wheels.
2. It also multiplies drivers efforts and give MECHANICAL ADVANTAGE.
Types of Steering Gear Boxes:
1.Worm and Wheel Type
2. Re-circulating Ball Type
3. Rack and Pinion Type
4. Cam and Lever Type
5. Worm and Sector Type
1.Worm and Wheel Type: This type of steering gear has a square cut screw threads at the end of the steering column; which forms a worm, at the end of it a worm wheel is fitted and works rigidly with it. Generally covered shaft is used for the worm wheel. The worm wheel can be turned to a new position the drop arm can be readjusted to the correct working position.
2. Re-circulating Ball Type: In this type of gear box the endless chain of balls are provided between the worm and nut members. The nut form a ring of rack having an axial movement. So that the sector on the rocker shaft racks, the balls roll continuously between the worm and nut. Being provided with return chambers at the ends of the worm. This method reduces friction between worm and nut members. This type of steering gear is used for heavy vehicles.
3. Rack and Pinion Type: This is common manual type of steering gear box is used in most of the vehicles. In this type of steering a pinion is provided the bottom end of the steering column. The teeth of the pinion wheel in mesh with corresponding teeth provided on the rack, the end of which are connected to the stub axle through the rod. The rotating motion of the pinion operates the rack in FORE and AFT direction which in turn operates the stub axle.
4. Cam and Lever Type: The cam and lever steering uses one or two lever studs fitted in taper roller bearing. When the worm in the form of helical groove rotates the stub axle and it also rotates along with it. This imports a turning motion to the drop arm shaft.
5. Worm and Sector Type: In this type the worm on the end of the steering shaft meshes with a sector mounted on a sector shaft. When the worm is rotated by rotation of the steering wheel, the sector also turn rotating the sector shaft. Its motion is transmitted to the wheel through the linkage. The sector shaft is attached to the drop arm or pitmen arm.
Power Steering:
Power steering reduces much strain on the part of the driver while negotiating sharp curves. It makes easy to turn sharp corners. It is usually arranged to be operative when the effort of steering wheel exceeds a predetermined value. It is fitted on heavy commercial vehicles and medium cars.
STEERING SYSTEM
Introduction: This system provides the directional change in the movement of an Automobile and maintain in a position as per the driver’s decision without much strain on him.
REQUIREMENTS OF STEERING SYSTEM:
a. It must keep the wheel at all times in to rolling motion with out rubbing on the road.
b. This system should associate to control the speed.
c. It must light and stable.
d. It should also absorb the road shocks.
e. It must easily be operated with less maintenance.
f. It should have self-centering action to some extent.
Functions of Steering System:
1. It helps in swinging the wheels to the left or right.
2. It helps in turning the vehicle at the will of the driver.
3. It provides directional stability.
4. It is used to minimize the tyre wear and tear.
5. It helps in achieving self-centering efforts.
6. It absorbs major part of the road shocks.
Main Components of Steering System:
Following are the main components of steering system:
1. Steering Wheel
2. Steering column or shaft
3. Steering Gear
4. Drop Arm or Pitman Arm
5. Drag Link
6. Steering Arm
7. Track-Arms
8. Track Rod or Tie-Rod
9. Adjusting Screws
The potential of electric field of a point charge:-
If potential 0-level is chosen in infinity The electric field potential at a point in space is equal to the amount of work we done by electric force to move the test charge from the point in question to infinity, divided by charge. The electric potential created by a point charge Qsource, at a distance r from the charge (relative to the potential at infinity), can be shown to be:
Electric field:-
• Intensity of an electric field E (or strength of an electric field or electric field) is vector characteristic. It is defined as the ratio of the force F acting upon the test charge to the magnitude of the test charge.
• The electric field of a point charge can be obtained from Coulomb's law.
• The magnitude of electric field produced by point charge Qsource at a distance r from this charge (in a point of M is where the electric field is defined).
Field lines:-
• An electric field has both magnitude and direction. The distribution of an electric field in space is visually represented by the intensity lines (or lines of force or field lines). Electric field-lines are drawn according to the following rules:
The direction of the electric field is everywhere tangent to the field-lines, in the sense of the arrows on the lines. The magnitude of the field is proportional to the number of field-lines per unit area passing through a small surface normal to the lines.
• The lines of force of a potential electric field (electrostatic field) that is created by electric charges originate on positive charges and terminate on negative charges. The electric field is stronger where the field lines are close together than where they are farther apart.
Electric Dipole:-
• An electric dipole is a pair of point electric charges of equal magnitude but opposite sign, separated by some small distance.
• The distribution of the charge in a dipole can be characterized by a parameter called the dipole moment p. The dipole moment is a vector which is directed from the negative charge towards the positive charge and is defined as:
Invoking Commands In AutoCAD:-
When you start AutoCAD and you are in the drawing area, you need to invoke AutoCAD commands to perform any operation. AutoCAD has provided the following methods to invoke commands:
• Keyboard
• Menu
• Toolbar
• Shortcut menu
• TOOL PALETTES
• Keyboard:-
You can invoke any AutoCAD command at the keyboard by typing the command name at the Command prompt, and then pressing ENTER or the SPACEBAR. If the Command prompt is not displayed as the last line in the command window area, you must cancel the existing command by pressing Esc (escape) on the keyboard. The following example shows how to invoke the LINE command from the keyboard:
Command: LINE or L « (L is command alias)
• Menu:-
You can also select commands from the menu. The menu bar that displays the menu bar titles is at the top of the screen. As you move the cursor over the menu bar, different titles are highlighted. You can choose the desired item by pressing the pick button of your pointing device. Once the item is selected, the corresponding menu is displayed directly under the title. Some of the menu items in the menu display an arrow on the right side, which indicates that the menu item has a cascading menu. You can display the cascading menu by moving the arrow pointer over the item and press the pick button.
• Toolbar:-
In Windows, the toolbar is an easy and convenient way to invoke a command. For example, you can invoke the LINE command by choosing the Line button in the Draw toolbar. When you choose a command from the toolbar, the command prompts are displayed in the command window.
Toolbar has numerous features that help to control their appearance. Toolbar features include:
1: Displaying Toolbars: The various toolbars can be displayed by selecting their respective check boxes in the Toolbars tab of the Customize dialog box. The Customize dialog box can be invoked by selecting Toolbars in the View menu. You can also display a toolbar from the shortcut menu by selecting the name of the toolbar. The shortcut menu can be displayed by right clicking anywhere on any toolbar on the screen.
2: Moving and Reshaping Toolbars
• Shortcut Menu:-
AutoCAD has provided shortcut menus as an easy and convenient way of invoking commands. These menus are context sensitive. They are invoked by right-clicking and displayed at the cursor location.
You can also right-click on the command window to display the shortcut menu. This menu displays the six most recently used commands and some of the window options like Copy and Paste.
You can right-click on the status bar to display the shortcut menu. This menu contains the options to change the settings of drawing tools.
• TOOL PALETTES:-
AutoCAD has provided TOOL PALETTES as an easy and convenient way of placing and sharing hatch patterns and blocks in the current drawing. By default, AutoCAD displays the Tool Palettes as a window on the right of the drawing area. Also, the TOOL PALETTES window can be turned on or off by either choosing the Tool Palettes button available on the Standard toolbar or by pressing the CTRL and 3 keys.
