unit8课文翻译

图

8.1a

和

b

同时简述了用于估计诸如加工时间和金属去除率之类的磨削作业不同参数的方程式。

During the surface-grinding operations, heavy workpieces are either held in fixtures or clamped on the

machine

table

by

strap

clamps

and

the

like,

whereas

smaller

workpieces

are

usually

held

by

magnetic

chucks.

在平面磨削时，重的工件用夹具固定或用压板 等夹紧在磨床工作台上，而小的工件则通常是用电磁卡盘固定的。

2.

Cylindrical grinding.

In cylindrical grinding, the workpiece is held between centers during the

grinding operation, and the wheel rotation is the source and cause for the rotary cutting motion, as

shown in Fig.8.2. In fact, cylindrical grinding can be carried out by employing any of the following

methods:

2.

圆柱面磨削：

在圆柱面磨削中， 作业时工件支撑在两顶尖之间，砂轮转动是导致回转切削运动的动力源，如图

8.2

所示。实际上，圆柱面磨削能通过采用下列任意方法来实现：

(1) The transverse method, in which both the grinding wheel and the workpiece rotate and longitudinal

linear feed is applied to enable grinding

of the whole length. The depth of cut is adjusted by

the cross

feed of the grinding wheel into the workpiece.

(1)

横向方法：这种方法 中砂轮与工件均旋转且采用线性纵向进给以保证能磨削整个长度。切削深度通过改变砂轮

对工件的横向进给来进行调整。

(2) The plunge-cut method, in which grinding is achieved through the cross feed of the grinding wheel

and no axial feed is applied. As you can see, this method can be applied only when the surface to be

ground is shorter than the width of the grinding wheel used.

(2)

插入< /p>

-

切削方法：这种方法通过砂轮的横向进给完成磨削而不采用轴向 进给。正如料想的那样，这种方法只在

要磨削表面比所用砂轮宽度短时才使用。

(3) The

full-depth method, which is similar to the transverse method

except that the

grinding allowance

is removed in a single pass. This method is usually recommended when grinding short rigid shafts.

(3)

全深度方 法：这种方法除了一次加工就能去除磨削余量外其它与横向方法相同。这种方法通常在磨削较短刚性

轴时推荐使用。

Internal grinding.

Internal grinding is employed for grinding relatively short holes, as shown

in

Fig.8.3.

The

workpiece

is

held

in

a

chuck

or

a

special

fixture.

Both

the

grinding

wheel

and

the

workpiece

rotate during the operation and feed is applied in the longitudinal direction.

内表面磨削：

内表面磨削用于相对较短的孔，如图

8.3

所示 。工件安装在卡盘或特殊夹具上。作业时砂轮

和工件都回转并且采用纵向进给。

Any desired depth of cut can be obtained by the cross feed of the grinding wheel. A variation from this

type is planetary internal grinding, which is recommended for heavy workpieces that cannot be held in

chucks.

通过砂轮的横向进给能得到任意所需的切削 深度。这种方法的一个变体是行星式内表面磨削，当工件较重不能用卡

盘固定时推荐使用 。

In

that

case,

the

grinding

wheel

not

only

spins

around

its

own

axis

but

also

rotates

around

the

centerline

of the hole that is being ground.

在这种情况下，砂 轮不但绕自身轴线回转，同时还绕被磨削孔的中心线旋转。

Centerless

grinding.

Centerless

grinding

involves

passing

a

cylindrical

workpiece, which is

supported

by

a

rest

blade,

between

two

wheels,

i.e.,

the

grinding

wheel

and

the

regulating

or

feed

wheel.

无心磨削：

无心磨削用于加工圆柱形工件，工件由托板支撑，在 两轮即砂轮和调节或进给轮之间通过去。

The grinding wheel does

the actual grinding,

while the regulating wheel

is responsible for rotating the

workpiece as well as generating the longitudinal feed. This is possible because of the frictional

characteristics of that wheel, which is usually made of rubber-bonded abrasive.

砂轮完成实际磨削，而调节轮负责旋转工件和产生纵向进给。由于 调节轮通常用橡胶粘结的磨料制成，其摩擦特性

使这成为可能。

As can be seen in Fig.8.4, the axis of the regulating wheel is tilted at a slight angle with the axis

of the grinding wheel. Consequently, the peripheral velocity of the regulating wheel can be resolved

into two components, namely, workpiece rotational speed and longitudinal feed.

正如在图

8.4

中所看到的那样，调节轮的轴与砂轮轴倾斜一个微小角度。因此调节轮的圆周速度 可以分解为两个分

量，即工件回转速度和纵向进给。

These can be given by the following equations:

V

workpi ece

＝

V

regulating

wheel

×

c os

α

Axial feed

＝

V

regul ating

wheel

×

×

sin

α

Where

c

is

a

constant

coefficient

to

account

for

the

slip

between

the

workpiece

and

the

regulating

wheel

(c=0.94~0.98).

其值可由下列公式给出：

V

工件

＝

V

调 节轮

×

cos

α

轴向进给＝

V

调节轮

×

c

×

sin

α

式中

c

是考虑工件和调节轮之间滑动的恒定系数