1. Read the following text and describe the drawings.

Bearing. Types of Bearings

Bearing is a machine part which sup­ports a moving part and

Fig. 25 Fig. 26

confines its mo­tion. That part of a shaft which rotates in a bearing

is called a journal. Bearings of parts having a rocking motion belong to the

second class, bearings with a continuous rotary motion form the great

majority of all bearings.

Bearings in which one rubbing surface slides over another are called plain bearings.They may be divided into two classes: 1) those with a continuous rotary motion and 2) those with an intermittent motion. Journal bearings belong to the first class. Bearings with a continuous rotary motion are the only ones in which an oil film pressure is adequate to support the journal itself.

Here are some types of bearings: a) a sliding bearing, b) an antifriction bearings, c) a radial ball bearing d) an axial ball bearing.

Ball bearing consists of two rings: an inner ring and an outer ring between which there are hardened steel balls spaced in ball retainer or cage. In rotating machines the balls are spaced so that they do not touch each other, thus reducing wear and noise.They require an absolutely parallel raceway to roll upon, entirely free from eccentricity of vibration.

Notes. ft./min – foot per minute

lb – pound = 453,59 grams.

Vocabulary

bearing підшипник

journal цапфа, шпонка

intermittent перервний, ритмічний

sliding ковзаючий

ball retainer сепаратор підшипника

2. Answer the questions on the text.

1. What is called a bearing? 2. What does a bearing support (confine)?

3. What part of a shaft is called a journal? 4. How many types of bearings can you mention? 5. What are they? 6. What types are antifriction bearings?

3. Choose the right variant.

1. Bearings with continuous rotary ____ form a great majo­rity of all

bearings.

a) angle b) force c) space d) motion

2. Journal bearings belong to the first ____.

a) group c) part d) class d) side

3.Bearings carry a load ____ at right angles to the shaft axis.

a) forcing b) acting c) producing d) rotating

4. A head of a rivet is an upset ____ of a rivet.

a) body b) top c) thread d) part

5.____ wear can be reduced by providing a sufficient bearing area and by adequate lubrication.

a) excessive b) additional c) great d) much

6. Usually right-hand ___ are used in screw fastenings.

a) sides b) threads c) forms d) types

7. Rivets are used____elements made of metals which are

difficult to weld together.

a) to connect b) to effect c) to make d) to hold