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第9讲螺纹连接件的画法 [兼容模式]

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第九讲 螺纹连接(Threads)
1. 螺纹要素及分类 Key Elements and types 2. 内外螺纹画法 Representations of internal and
external threads

3. 螺纹联接 Threaded connection 4. 螺*艄碳 Threaded fasteners
1

螺孔
Threaded hole

2

9.1

螺纹的形成、结构和要素
一个与轴线共面的*面图形(三 角形、梯形等),绕圆柱面作螺旋运 动,则得到一圆柱螺旋体 ——螺纹。
A cylinder thread is a long narrow projection of uniform cross the section in the form of helix ont the surface of a cylinder

Generation , structure and key elements of thread

⒈ 螺纹的形成Generation

螺旋线 Helix

A



制在圆柱体外表面上的螺*型 螺纹。External thread is a thread on the outside of a
cylindrical surface ,as on a shaft.

制在圆柱体内表面上的螺*心 螺纹。Internal thread is a thread on the inside of a
cylindrical surface, as in a hole.
3

2. 螺纹加工 Machining screw thread
工件
A Shaft

工件旋转
The part rotates

卡盘
Fixture

车刀Cutter

车刀沿轴向移动
The cutter move along the axis

车外螺纹
Lathe external thread

车内螺纹
Lathe internal thread

4

⒊ 螺纹的要素Key Elements of
⑴ 螺纹的牙型 Form of thread
在通过螺纹轴线的剖面上,螺纹的轮廓形状。The
cross section of thread cut by a plane containing the axis.

threads

牙型 Form

常用的有:Most often used:
三角形
Metric

梯形
ACME

锯齿形
Buttress

5

⑵ 螺纹的大径和小径

Major diameter and minor diameter

大径:与外螺纹牙顶或内螺纹牙底相切的假想圆柱面的直 径。D、d Major diameter: The largest diameter of a screw thread 小径:与外螺纹牙底或内螺纹牙顶相切的假想圆柱面的直 径。 D1、d1 Minor diameter: The smallest diameter of a screw thread
牙底
Root

牙顶
Crest

小径
牙顶
Crest

大径
牙底Root
6

螺纹的中径Pitch diameter:
一个假想圆柱的直径。该圆柱的母线通过牙型 上沟槽和凸起宽度相等的地方。The diameter of an imaginary
cylinder where the thread width is equal to space between the threads.

牙底
Root

内螺纹
Internal thread

牙顶
Crest

牙顶
Crest

外螺纹 牙底Root External thread

小径 Minor dia. D1、 d1 中径 Pitch dia. D2、 d2

大径 Major Dia. D、 d
7

⑶ 螺纹的线数Number of

threads

?沿一条螺旋线形成的螺*凶龅ハ 螺纹;Single thread: with only one start. ?沿两条或两条以上在轴向等距分布 的螺旋线所形成的螺*凶龆嘞呗 纹。Multiple thread: with two or more starts

单线螺纹
Single thread

双线螺纹
Multiple thread

瓶口三线螺纹
Triple-start thread
8

⑷ 螺距和导程 Pitch and Lead
螺纹上相邻两牙在中径线上对应两点之间的轴向距离P 称为螺距。Pitch: The distance from a point on one thread to the corresponding point
on the adjacent thread, measured parallel to the axis of the thread.

同一条螺纹上相邻两牙在中径线上对应两点之间的轴向 距离L称为导程。Lead: The distance a thread advances axially in one turn.
螺距P =导程L 导程L 螺距P

单线螺纹(Single thread): P=L

多线螺纹(Multiple thread): P=L/n

9

⑸ 螺纹的旋向 How the thread spiral
右旋(常用) :顺时针旋转外螺纹时旋入的螺纹为右旋。除非特别 注明,螺纹均为右旋 Right-hand(Default):A thread is always considered to be
right-hand unless otherwise specified.

左旋:加标记:“LH” Left-hand:always labeled ‘LH’ on drawing 右边升高 左边升高
Slant upward to the left Slant upward to the right

左旋 Left-hand

右旋

Right-hand

注意:只有上述五要素完全相同的内、外螺纹 才能旋合在一起。The external thread and internal thread can be
mated only when their five elements are all the same .
10

外螺纹External thread
牙顶Crest 螺尾Thread runout
小径 Minor dia. 大径 Major dia.

内螺纹Internal thread
牙底 Root

螺距Pitch 中径 Pitch dia. 牙型Thread form

倒角
Chamfer

螺距 Pitch

牙型 Thread form

内外螺纹旋合三要素:牙型、大径、螺距
Three key elements for mating : thread form, major dia. and pitch
11

螺纹收尾和退刀槽
螺尾Thread runout

Thread runout and relief

退刀槽Thread relief

外退刀槽External relief 退刀纹Incomplete thread
due to tool exits

退刀纹
Incomplete thread

退出车刀
Exit completely

开始退刀
Cutting tool begins to exit

内退刀槽Internal relief

12

9.2 螺纹的种类

Classification of threads commonly used 粗牙螺纹Coarse 普通螺纹Metric thread 细牙螺纹
Fine

连接 螺纹
Connecting

密封管螺纹Screw-sealed 管螺纹Pipe thread 非密封管螺纹Non-screw-sealed 梯形螺纹Trapezoidal thread

螺纹
Thread

传动 螺纹
Transmitting

锯齿形螺纹Buttress thread

13

常用的几种螺纹的特征代号及用途
The labels and common uses of some threads

螺 纹 种 类Types
粗牙 普 通 Coarse

特征 代号
Labels

外 形 图
Profiles


Use



是最常用的联接螺纹 M
Most often used connecting thread

联接 螺纹
Conne -cting

纹 细牙 螺 Metric
Fine

用于细小的精密或薄壁零件
Used for fine or thin part

管螺纹
Pipe thread

G

用于水管、油管、气管等薄 壁管子上,用于管路的联接。
Used for connection of pipes or tubes of water, oil or gas

梯形螺纹 传动 螺纹
Transmission Trapezoidal

Tr

用于各种机床的丝杠,作 传动用。Power transmission, like in lead
screw.

锯齿形 螺纹
Buttress

B

只能传递单方向的动力。
Transmit power in one direction only, like in a car jack 14

9.3 螺纹的规定画法Conventional representation of threads
★牙顶用粗实线表示 (外螺纹的大径线,内螺纹的小径线)。
The crest line ( i.e. major dia. for external thread and minor dia. for internal thread) defined by thick solid line.

★牙底用细实线表示 (外螺纹的小径线,内螺纹的大径线)。
The root line ( i.e. minor dia. for external thread and major dia. for internal thread) defined by thin solid line.

★在投影为圆的视图上,表示牙底的细实线圆只画约3/4圈。
On an end view, the root should be represented by a circle of approximately 3/4 of the circumference drawn by thin solid line .

★螺纹终止线用粗实线表示。The thread end lines (The limits of useful
thread) should be shown by a thick solid line.

★不管是内螺纹还是外螺纹,其剖视图或断面图上的剖面线 都必须画到粗实线。For threaded parts shown in a sectional view ,The section lines
should be extended to the thick solid lines.

15

⒈ 外螺纹画法 Representation of external threads
大径线画粗实线
Major dia. by thick solid lines

倒角圆不画
Chamfer circle not shown on such view

小径线画细实线且画到倒角内Minor
dia. by thin solid lines and extended cross the chamfer line

小径圆约画3/4圈 螺纹终止线画 粗实线Thread end
line by thick solid line Minor dia. by a thin solid line circle of approximately 3/4

外螺纹剖视画法:
Section of external thread: A 大径
小径

小径≈0.85d

A- A

A 螺纹终止线画一小段
Thread end line appears short

剖面线画到粗实线
Section lines extended to thick solid lines 16

⒉ 内螺纹画法 Representation of Internal threads
大径线画细实线
Major dia. by thin solid lines

倒角圆不画
Chamfer circle not shown on such view

小径线画粗实线,≈0.85d
Minor dia. by thick solid lines and extended cross the chamfer line

螺纹终止线
Thread end line by thick solid line

大径圆约画3/4圈Major
dia. by a thin solid line circle of approximately 3/4

A

A- A

A 剖面线画到粗实线
Section lines extended to thick solid lines 17

不穿通螺纹孔的画法Blind tapped hole:

钻孔
Drill

攻丝
Tap

120°
18

0.5D

⒊ 螺纹局部结构的画法
⑴ 倒角Chamfer
C2 2×45° 2×45°

P505表

⑵ 退刀槽Relief
b

⑶ 螺尾 Runout
与轴线成30°细实线
Thin solid lines 30°to the axis

?螺尾只在有要求时 才画,不需标注。
Runout not shown unless it’s required.

19

4. 螺纹联接的画法Representation of threaded connection
A A-A

按不剖画
As non-sectioned

A 旋入深度
Length of screwed

内、外螺纹剖面线方向相反
Reversed section lines for internal and external threads

? 大径线和大径线对齐;小径线和小径线对齐。
Two major diameters are collinear, so does the two minor diameters. For threaded connection part, external thread covers internal thread.

为什么?

?旋合部分按外螺纹画;其余部分按各自的规定画。
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画图步骤Steps:

? 画外螺纹(小径画0.85d )
External thread (Major dia. as 0.85d)

? 确定内螺纹的端面位置
Determine the location of internal thread ends

? 画内螺纹及其余部分投影
Finish the remaining part of internal thread.
21

9.4 螺纹的标注
⒈ 标注的基本模式
螺纹代号
Designation of threads

Thread designation
General symbols

公称直径
Nominal dia.

×

螺距 或 导程(P螺距)
Pitch or Lead (P& pitch value)

LH (如为左旋)
LH (if left-hand)



一个或两个公差带代号
One or two tolerance zone symbols



旋合长度代号
Symbol for length of engagement

中径和顶径 公差带代号

长Long:L 中等Middle:N 短Short:S

?粗牙螺纹不标注螺距; P502 ?右旋螺纹省略标注; ?旋合长度为中等时,“N”可省略。
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⒉ 标注示例 Example 例 1:
普通螺纹
Metric thread

P502
短旋合长度
Short engagement length

M 20 ×2 LH -5g6g - s
顶径公差带代号
Major dia. tolerance zone

大径Major dia. d=20 螺 距 2 (细 牙 )
Pitch is 2 (fine thread)

中径公差带代号 左旋
Left- hand Pitch dia. tolerance zone

例 2:
梯形螺纹

Tr40×7(14/2)-7H-L

两公差相同则只标一个。小写字 母表示外螺纹,大写字母表示内 螺纹。If the two tolerance zone symbols are
the same, only one indicated。Capital for internal and small for external threads.

Trapezoidal thread

大径Major dia. D=40 螺距 7导程14,双线螺纹
Pitch is 7, lead is 14 ,double thread.

长旋合长度Long engagement length 中径、顶径公差 带代号Major dia.
and pitch dia. tolerance zone

右旋 Right hand

23

⒊ 标注方法
M20× 2

Thread notes

M20-7H

P502

外螺纹
External

内螺纹
Internal

G1

注: G后面的数字不 是管螺纹的大径 ,而是它的公称 直径。The value
after letter “G” is not the major dia. but its nominal dia.

尺寸界线应 从大径引出!
The extension lines should be from the major dia.

管螺纹

1 in = 25.4mm P504

24

9.5 螺*艄碳谋昙呛突═hreaded fasteners
常用的螺*艄碳校郝菟ā⒙荻ぁ⒙葜⒙菽负 垫圈等。由于这类零件都是标准件,通常只需在装配图 中用简化画法画出,同时给出其规定标记。 标记方法按 “GB” 有关规定。
Threaded fasteners, which include bolts, screw, stud, nut and washer etc., are standardized. On assembly drawings they are specified by means of designations and shown in conventional representation. Designation according to “GB”

25

⒈ 六角螺母

Nuts

P 513

规定标记 Specified designation: 例: 螺母 GB/T 6170 M12 国标号 螺纹规格 GB symbol
for nuts Thread size

简化画法 Simplified drawing:
0.8d 2d
26

? 比例画法见P414 图15-20
? See P414 Fig. 15-20 for proportional drawing as

⒉ 六角头螺栓 Bolts 规定标记:Specified designation

P506
螺栓长度L
Length of stud L

例:螺栓GB/T 5782 M12×80
0.1d×45°

Simplified drawing

d 2d 0.7d L (由设计决定)
Determined by design

简化画法:

? 比例画法见 P414 图15-20
See P414 Fig. 15-20 for proportional drawing as

27

⒊ 垫圈 Washers

P514

规定标记:Specified designation
例: 垫圈GB/T 97 12
规格,指用于M12的螺栓或螺柱 ? P514为*垫圈,P515为弹簧 垫圈 P514 shows plain washers while P515
1.1d 2.2d
28

Size 12 means that it is used for M12 bolts or studs

简化画法Simplified drawing : 0.15d

about spring washers

⒋ 螺钉 Screws
Specified designation

P511
M8×45
螺钉长度L 0.1d×45°
Length of screw L

规定标记: 例:螺钉GB/T 65
开槽圆柱头螺钉
Slotted cheesed head screw

简化画法:
Simplified drawing

1.5d 0.2d

0.3d
P508 内六角圆 柱头螺钉
Hex. Socket cheese head screw

2d 0.6d L
P510开槽沉头 螺钉 Slotted
countersunk head screw

d

29

9.6 螺*艄碳芭渫嫉幕
Representation of fasteners in assembly drawing

⒈ 螺栓联接 Bolt joints
?用于将两个都有通孔的 零件联接Used to hold two parts
together each of which has a through and clearance hole.

30

螺栓联接装配图画法 Drawing of bolt joints
0.3d ?螺栓大径为d Major dia. Of the bolt is ?被联接件的孔径=1.1d
Holes in two parts drawn as diameters of 1.1d d

?两块板的剖面线方向相反 δ2 L δ1
Reserved directions of section lines for two parts

?螺栓、垫圈、螺母沿轴线剖到按不剖画
Bolt, washer and nut as non-sectioned along the axis

?螺栓的有效长度按下式计算
Design length of the bolt is calculated as :

Ld=δ1+ δ2+0.15d(垫圈厚 height of washer) +0.8d(螺母厚height of nut)+0.3d

将Ld与标准规定的公称长度系列L比较,选择最接*于计 算值的公称长度。(P506) Compare the length Ld with the nominal length L
series specified in the standard and choose the one closest to the calculated value.

?参见P416 图15-23

Refer to P416 Fig. 15-23

31

画图步骤 Steps:

先画俯视图较方便
Top view first recommended

32

2. 螺钉联接
?螺钉连接用于受力不大 且不要求调整的机构。
Screw joints are used on machines requiring few adjustments and lower strength.

Screw joints

光孔
Clearance hole

螺纹孔
Tapped hole

33

螺钉联接画法 Drawing of bolt joints
螺钉计算长度:
Length calculated by:

Ld=bm+δ

δ

查表定L -P511
Find L in list of P511

bm 0.5d

L

旋合长度bm与被零件材料有关:
Length of screwed bm is determined by material of jointed part:

45°

?钢Steel: ?铸铁Cast iron: ?铜Copper: ?铝Aluminum:

bm=d bm=1.25d bm=1. 5d bm=2d

?参见P418 图15-28
Refer to P418 Fig. 15-28
34

常见的错误画法Incorrect drawings:

×


允许将螺纹画到底
Simplified representation permitted

×
螺纹终止线应 高于两零件分界
Thread end line should be higher than the demarcation line

螺钉末端应不拧到底The
screw should not touch the end of the tapped hole. 35

画在何处?
The structure of the cone?

锥顶角度?
What is the angle?

剖面线画到何处?
Where the section lines extended to?
36

倾斜角度?
How inclined?

3. 双头螺柱联接
螺母端
Nut end

A stud joints

光孔
Clearance hole

旋入端
Metal end

螺纹孔
Tapped hole

?螺柱联接用于零件材料较厚不能制通孔的机构。
Stud joints are used on machines which are difficult to drill through holes in .
37

双头螺柱联接画法 Representation of stud joints
Ld= δ +0.15d+0.8d+0.3d
查表 P507
δ

L

? 旋合长度bm(即螺柱旋入 端长度),同螺钉一样由被 联接件的材料决定。 As in
screw joint, length of screwed bm is(i.e. the length of metal end of the stud ) determined by material of jointed part

对齐
Aligned

?螺柱画法参见P415图15-20 ,螺母端螺纹长度可*似为2d。See P415
Fig. 15-20 for drawing of stud ,the length of nut end can be drawn as 2d.

?螺柱联接画法参见P417 图15-25 和15-26

bm

Refer to P417 Fig. 15-25 and 15-26
38

小 结Conclusion
1. 在螺纹的规定画法中,要抓住三条线。The key is
three lines in the conventional representation of thread:

?牙顶用粗实线表示 (用手摸得着的柱面)。
The crest by thick solid line (The portion that can be touched)

?牙底用细实线表示 (用手摸不着的柱面)。
The root by thin solid line (The portion that can’t be touched)

?螺纹终止线用粗实线表示。The thread end line by thick line. ☆ 注意剖视图中剖面线的画法。Note the section lines.

2. 螺纹标注的目的,主要是把螺纹的类型和参数 体现出来。尺寸界线要从大径引出。The notes of threads
show the types and parameters。The dimension extension lines should be from the Major dia.
39

3 . 螺栓、螺钉、螺柱、螺母、垫圈都是标准件, 掌握其联接装配图的规定画法(简化画法),注 意比较它们的相同点和区别。掌握其标记内容。
The screw fasteners are standardized which are specified by means of designations and their representations (conventional and simplified)in assembly drawing are symbolized 。

4. 会查阅螺纹及螺纹联接件的标准手册。
Use thread tables to specify or draw threaded fasteners

40

作业:*题集 P97, 98(1-3),99(1)
参考教材Refer to:P403-420

下下周:期中测验
(尺寸标注,剖视,轴测图,螺纹)

Next week: Mid-exam
(dimensioning, section, isometric drawing, thread)
41

ANSI中表达外螺纹的两种方式: Two representing for external threads in a drawing –ANSI:

42

ANSI 内螺纹
ANSI internal thread:

细节图(剖视)

简图(剖视)

未剖视

侧视

43

ANSI 公制螺纹标注
ANSI metric thread specification:

44

ANSI 英制螺纹标注
ANSI thread specification (in inches):

大径0.5英寸 每英寸28齿 牙型注 C系列(C指粗糙) 配合类型(3为精密,2 为普通,1为松配合) B指内螺纹(A指外螺纹) 注:UN是普通牙型
45

螺 纹 代 号

螺 纹 种 类

大径

导 程

螺 距 线 数 公差带代号与精度

旋 向

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