SANY LATIN AMERICA
1-6
SY195/205/215/225C9 Crawler Hydraulic Excavator
Introduction
Shop Manual - June 2013
Example
Standard size
Tolerance
Shaft
Hole
φ
60
-0.030
-0.076
+0.046
0
2. Standard clearance and standard value
●
The clearance made when new parts are
assembled is called the "standard clear-
ance", which is indicated by the range from
the minimum clearance to the maximum
clearance.
●
When some parts are repaired, the clear-
ance is generally adjusted to the standard
clearance.
●
A value of performance and function of
new products or equivalent is called the
"standard value", which is indicated by a
range or a target value.
●
When some parts are repaired, the value
of performance/function is set to the stan-
dard value.
3. Standard interference
●
When the size of a hole is smaller than the
size of a shaft because of the standard
size and tolerance, the difference between
these sizes is called the "interference".
●
The range (A – B) from the difference (A)
between the minimum size of the shaft and
the maximum size of the shaft to the differ-
ence (B) between the maximum size of the
shaft and the minimum size of the hole is
the "standard interference".
●
After repairing or replacing some parts,
measure the size of their hole and shaft
and check that the interference is in the
standard range.
4. Repair limit and allowable value
●
The size of a part changes due to wear
and deformation while it is used. The limit
of changed size is called the "repair limit".
●
If a part is worn to the repair limit must be
replaced or repaired.
●
The performance and function of a product
lowers while it is used. A value below which
the product can be used without causing a
problem is called the "allowable value".
●
If a product is worn to the allowable value,
it must be checked or repaired. Since the
permissible value is estimated from vari-
ous tests or experiences in most cases,
however, it must be judged after consider-
ing the operating condition and customer's
requirement.
5. Clearance limit
●
Parts can be used until the clearance be-
tween them is increased to a certain limit.
The limit at which those parts cannot be
used is called the "clearance limit".
●
If the clearance between the parts exceeds
the clearance limit, they must be replaced
or repaired.
6. Interference limit
●
The allowable maximum interference be-
tween the hole of a part and the shaft of
another part to be assembled is called the
"interference limit".
●
The interference limit shows the repair limit
of the part of smaller tolerance.
●
If the interference between the parts ex-
ceeds the interference limit, they must be
replaced or repaired.
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