Assembly Drawings 339
dharm
d:\N-Design\Des18-4.pm5
The closed end cover 5 is used on the right side of the worm shaft and fastened to the housing
while end cover 7 is fastened to the housing on the left side.
The worm wheel 4 is fitted on the wheel shaft by means of a key. The oil seal 11 and roller
bearing 6 are assembled in both the wheel shaft end covers 8. These end cover assemblies are
located on the wheel shaft assembly and placed over the housing. The top cover 12 is placed over
the housing and the wheel shaft end covers are fastened to both the housing and top cover, thus
completing the assembly.
Exercise
The details of a single stage worm gear speed reducer are shown in the Fig. 18.53. Assemble the
parts and draw to a suitable scale, (i) sectional view from the front and (ii) the view from the left.
SOLUTIONS FOR GUIDANCE
The assembly drawings are very critical and the principles of making the assembly drawings
from the part drawings are explained in detail in the text. The preparation of assembly drawings
from part drawings, require lot of skill. This can be achieved only through practice.
As a guide to the students, for majority of the projects considered in this chapter, one
assembly drawing; plain or sectional, is presented. Some are included in the text itself and for the
remaining ones, the views are given below. For example, Fig. 18.1A shows the assembly drawing
of the components given in Fig. 18.1 and so on. The students are advised to study these views and
develop other required ones.
50
24
60 TEETH
PCD 158
R5
R5
KEY WAY, 6×2
4
8
30°
f^28 f^72 f (^116) f^28 f^24
33
(^1019)
12
4
f^36 f^48 f^588
R2
6 HOLES, DIA 4
EQUI-SP, PCD 96
12
f48
f^2430°6 8
8
1×45°
f42
f^206
10
KEY WAYS,
6×3
f^24
2×45°320
67
f^2840
76 67
f^2420 2×45°
8 1×45°
f^36 f24
(^611)
30°
Fig. 18.53 Speed reducer