ing is very difficult and these types need a fixture with very high
accuracy.
With respect to the realization difficulty of the accuracy,
when functionally connected surfaces are machined in separate
clampings, the connecting types can be pided into two types:
loosely and strictly tolerance-related connections (Fig. 2).
The group of loosely tolerance-related connections consists
of accuracy-related requirements, which can be achieved rela-
tively easily even in cases when the connected surfaces are ma-
chined in two separate clampings. In the case of these functional
connecting types the fixture accuracy is critical only with respect
to parallelism or perpendicularity to the machine table.
The group of strictly tolerance-related connections consists
of accuracy-related requirements which can be achieved only
with difficulty in cases when the connected surfaces are ma-
chined in two separate clampings. They need a high accuracy of
the fixture and of the locating elements of the workpiece. For
these connecting types the connected surfaces need to be ma-
chined in one clamping or, such surfaces should be machined in
two separate clampings, only when there is no other solution.
The faces of a workpiece, depending on the surfaces they
contain, have appropriate attributes. The face is: “machined”
when it contains a machined surface, it is “connected” when
it contains a connected surface, it is “strictly connected” when
it contains a strictly connected surface, and it is “loosely con-
nected” when it contains a loosely connected surface.3 Identification of the locating and clamping entities
3.1 Plane locating types of the workpiece
Determining of the plane locating types was with the help of
the analysis of technological facilities of horizontal machining
centers and existing clamping fixtures. There are three types of
plane locations (Fig. 4): horizontal (denoted with “pos1”), verti-
cal (“pos2”), and vertical with partial machining of the locating
face (“pos3”).
The selection of a plane locating face with a given plane lo-
cating type determines the set of workable faces.
3.2 Side locating types
From an analysis of existing clamping fixtures and the corres-
ponding literature, there are four basic types of side location
(Fig. 5) [8, 10]:
(1) Side location by using surfaces, which are on the adjoin-
ing faces of the plane locating face
(2) Side location using two inside diameter on the plane lo-
cating face
(3) Side location by using one inside diameter on the plane
locating face and a face on one of the adjoining faces(4) Side location by using two threaded joints on the plane
locating face
3.3 Clamping types
According to the direction of clamping forces, the clamping can
be perpendicular to the plane locating surface (type s1) or paral-
lel with the plane locating surface (type s2). The basic type s1,
depending on the location of clamping faces, can be further di-
vided into subtypes s11, s12, and s13. In the case of s11, the
clamping surfaces are on the adjoining sides of the plane locating
face. In the case of s12, the clamping surface (or surfaces) is on
the opposite side of the plane locating face, and in type s13, the
clamping is on the through hole (Fig. 6).
One of the specific ways of clamping is clamping by screws
and threaded joints on the plane locating face which is called
type s3.
The number of clamping points is also a very important char-
acteristic of clamping. According to the number of clamping
points, clamping is differentiated in one, two, three, and four
points. Adding these to the previous basic types, the possible 变速箱的集成设置英文文献和中文翻译(2):http://www.youerw.com/fanyi/lunwen_8355.html