问题 问答题 简答题

修理机械设备时,常用的拆卸方法有哪些?

答案

参考答案:

(1)击卸法拆卸:即利用锤子敲击零件的拆卸方法,但要注意不能损伤零部件。

(2)拉拔法拆卸:即利用通用或专用工具与零,部时相互作用产生的静拉力或不大的冲击力拆卸零,部件,如锥销的拉拔,轴端的滚动轴承,齿轮等的拉卸。

(3)压卸法拆卸:即利用机械或拆卸工具与零,部件作用产生的静压力来拆卸零部件。如在压力机上拆卸过盈配合的轴和齿轮。

(4)温差法拆卸:即利用加热包容件,或冷却包容件来进行拆卸。主要用于拆卸尺寸较大,配合过盈量较大或无法用击,压,拉法拆卸的零件。

(5)破坏拆卸:用于拆卸固定连接件或轴和轴套相互咬死的情况。此法易损坏零件,要尽量避免使用。

阅读理解

阅读理解。

     As we know, there are differences between western culture and Chinese culture. We can see differences

when we pay attention to the way words are used. Let's look at the words about animals and plants. Most

expressions in Chinese about the dog, for example, "a homeless dog", "a mad dog", "a running dog" and "a

dog catching a mouse", have negative (消极的) meanings. But in western countries, dogs are thought to be

honest and good friends of humans. In English, people use the dog to describe positive (积极的) actions.

For example," you are a lucky dog" means you are a lucky person. And "every dog has its day" means each

person has good luck sometimes. To describe a person's serious illness, they say "sick as a dog". The word

"dog-tired" means very tired. However, Chinese love cats very much. But in western culture, "cat" is often

used to describe a woman who is cruel (冷酷的). There are many other examples of how "cat" is used

differently as well.

     The rose is regarded as a symbol (象征) of love in both China and some western countries. People think

the rose stands for (代表) love, peace (和平), courage and friendship. And the rose is the national flower of

England, America and many other countries.

     The words about plants and animals are used in positive or negative ways in different cultures. We can

learn about many differences in cultures by comparing how some words are used.

1. The word "dog" in Chinese usually ______.

A. shows peace

B. stands for friendship

C. has a negative meaning

D. has a positive meaning

2. "Every dog has its day." means "______".

A. Everybody in the world is lucky.

B. Each person lives his own way of life.

C. If one works hard, he's sure to succeed.

D. Everybody has a time in life to be lucky.

3. Western people usually use "cat" to refer to (指代) "______".

A. a tired person

B. a brave man

C. a homeless person

D. an unkind woman 

4. Which of the following is true according to the passage?

A. Words show differences in culture.

B. Chinese people prefer dogs to cats.

C. Western people think cats to be good friends.

D. Rose is the national flower of all western countries.

5. What's the best title for the passage?

A. Negative or Positive

B. Different Countries Have Different Culture

C. Rose Means the Same in Chinese and English

D. What Dog and Cat Mean in Chinese and English

多项选择题