TERM – 2^ND TERM

WEEK TWO

Class: Senior Secondary School 3

Age: 17 years

Duration: 40 minutes of 5 periods each

Date:

Subject: AUTO MECHANICAL

Topic: MAINTENANCE OF STEERING SYSTEMS II

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

I.) Identify the types of steering box

II.) Discuss the principles of Operation of Ackerman Linkage

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures,

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION	TEACHER’S ACTIVITY	STUDENT’S ACTIVITY
STEP 1 INTRODUCTION	The teacher identify and discusses the types of steering box	Students listens attentively to the teacher
STEP 2 EXPLANATION	Teacher explain the principles of operation of Ackerman linkage, i.e, camber angle, caster angle, toe in and toe out, kingpin inclination.	Students exhibit attentiveness and active engagement
STEP 3 NOTE TAKING	The teacher writes a summarized note on the board	The students copy the note in their books

NOTE

MAINTENANCE OF STEERING SYSTEMS II

Types of Steering Box

1. Rack and Pinion Steering: This type of steering box uses a gear mechanism to translate the rotational motion of the steering wheel into linear motion to turn the wheels. It's commonly used in modern vehicles due to its simplicity and responsiveness.

2. Recirculating Ball Steering: In this type, a worm gear on the end of the steering shaft engages a sector gear that moves a series of recirculating ball bearings. As the bearings move along the grooves, they push a piston connected to the steering linkage, turning the wheels. It's often found in older vehicles and trucks due to its durability and ability to handle heavy loads.

3. Worm and Sector Steering: This steering box consists of a worm gear on the end of the steering shaft that engages with a toothed sector gear. As the steering shaft rotates, the sector gear moves, turning the wheels. It's less common in modern vehicles but was widely used in older cars.

4. Power Steering Box: This is not a separate type but rather a feature that can be added to any of the above steering boxes. Power steering uses hydraulic or electric assistance to make steering easier, especially at low speeds or when parking.

Principles of Operation of Ackerman Linkage

Ackerman linkage is a steering geometry designed to improve handling by ensuring that all four wheels follow the same path during a turn, reducing tire wear and improving stability.

It achieves this through several principles:

Camber Angle: This is the angle at which the wheels are tilted relative to the vertical axis. In Ackerman steering, the camber angle is adjusted to ensure that the tire maintains optimal contact with the road surface during cornering.
Caster Angle: This is the angle at which the steering axis intersects with the ground. A positive caster angle helps the wheels return to the straight-ahead position after a turn, improving stability and steering feel.
Toe-In and Toe-Out: Toe refers to the angle at which the wheels point inward or outward when viewed from above. In Ackerman steering, the front wheels are set with a slight toe-in to compensate for the lateral forces during cornering and improve straight-line stability.
Kingpin Inclination: This is the angle at which the kingpin (the pivot point of the steering knuckle) is inclined inward toward the center of the vehicle. It helps reduce steering effort and improves directional stability.

EVALUATION: 1. Identify the 4 types of steering box

What is Ackerman linkage?
Identify and describe the principles of Ackerman linkage

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively

Lesson Notes By Weeks and Term - Senior Secondary 3