Bolt joints

THREAD JOINTS

Washer 20.01.016 State Standard 11371-78.

Table 4.8

Nominal thread diameter dn	d1 type	d2	S
	17.5			3.0
				3.0
				3.0
				3.0
				4.0

Figure 4.20 – Types of washers

Basic types of joints with the use of considered previously connecting elements are connection by a bolt, screw, stud, and also pipe joints. These types of joints (except of a pipe) have the three depictions: structural, simplified and conventional.

The structuraldepiction suits all structural elements of the parts of a joint.

The simplifieddepiction is used for details without chamfers, a thread is represented along the length of a bar of a thread part, a clearance between a bar and an opening is not shown.

A conventionaldepiction is used in those cases, when the diameter of a bar on a drawing less than 2 mm. State Standard 2.315:2008 is used for simplified joints.

Pipe joints are done only structurally.

A bolt joint consists of a bolt – 3, a nut –5 and a washer –3 (fig.4.21, а). There are two parts in the bolt joint also (d₁ and d₂ – their thickness).

At the structural drawing of a thread connection opening diameter equals 1.1 × d_n (where d_n is a nominal diameter of a bolt thread). Actual working length of a bolt is found as a sum of the followings parameters: L= d₁+ d₂ + H _n + S _w + 0.25× d_n,

where d₁ and d₂ – the thickness of connecting parts, H _n– the thickness of a nut, S _w – the thickness of a washer, d_n – the nominal diameter of a thread. The received sum is rounded to the nearest from the resulted standard row of workings lengths – L at table 4.9.

Table 4.9

Working length of a bolt L, mm	Threaded length l0 according to the set nominal diameter of a thread dn
50,55,60,65,70,75,80

At the simplified drawing of a bolt joint for the calculation of working length of a bolt - L the dependence is used:

L= d₁ + d₂ +1,3× d_n,

where d₁ and d₂ – the thickness of connecting parts, d_n – the nominal diameter of a thread.

The parameter 1,3× d_n approximately takes into account the structural sizes of the thickness of a washer, the height of a nut and stocked on length of a bolt. For the implementation of the simplified drawing of a bolt joint the followings correlations are used:

D=2 ´ d_n; D_w=2,2 ´ d_n; H=0,8 ´ d_n; S_w=0,15 ´ d_n; h=0,7 ´ d_n.

The structural drawing of a bolt joint is presented in figure 4.21, a and it is simplified – in figure 4.21, b.

а) b)

Figure 4.21 – The bolt joint

Дата добавления: 2014-10-15