Joints and connections – Member deformed in situ – Deformation occurs simultaneously with action of separate,...
Reexamination Certificate
2001-03-29
2003-04-01
Hartmann, Gary S. (Department: 3671)
Joints and connections
Member deformed in situ
Deformation occurs simultaneously with action of separate,...
C403S282000, C403S375000, C029S892000, C029S892110, C029S892300, C474S902000, C492S001000, C492S027000
Reexamination Certificate
active
06540428
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a caulking roller and a sintered flanged pulley caulked by the caulking roller. Caulking is the operation in which two parts are joined tightly together to prevent leakage or slippage, in the present case by mating the two parts in the joint and upsetting the material of at least one of the two parts to interlock the parts and make them tight against one another.
2. Description of the Related Art
In a timing drive of a vehicular engine are used various pulleys on which a toothed belt is entrained, such as a cam pulley, a crank pulley, and an oil pump pulley. In each of these pulleys, annular flanges for keeping the position of the toothed belt and for preventing disengagement of the same belt are formed on both sides of a pulley body. However, the pulleys each having such annular flanges on both sides of its body are difficult to be formed integrally by sintering. According to the conventional method for fabricating sintered pulleys with annular flanges on both sides of their bodies, first a pulley body having a flange portion on one side is formed integrally by sintering, and then an annular flange formed using a separate material is caulked or tightly joined to the sintered pulley body.
FIGS. 4 and 5
illustrate a sintered, flanged cam pulley
1
as an example of a pulley to be used in a timing drive of a vehicular engine, of which
FIG. 4
is a sectional view showing a state before caulking an annular flange
3
to a sintered cam pulley body
2
and
FIG. 5
is a sectional view showing a caulked state of the annular flange
3
to the pulley body
2
.
As shown in
FIG. 4
, teeth
2
a
are integrally formed on an outer periphery of the sintered cam pulley body
2
, a flange portion
2
b
is integrally formed on an outer periphery of one end of the pulley body
2
, and an axial bore
2
c
with key way is formed in a boss portion of the pulley body . Further, at the opposite end of the pulley body
2
, i.e., on the side opposite to the integral flange portion
2
b
, there is formed an axial annular projection
2
d
. On an outer periphery side of the annular projection
2
d
is formed a stepped portion
2
e
. The tip of the annular projection
2
d
constitutes an allowance for caulking. The annular flange
3
is formed in a thin disc shape using a cold rolled steel sheet (e.g., SPCC) or a carbon steel (e.g., S35C).
The annular flange
3
is caulked to the sintered cam pulley body
2
in the following manner. An inner peripheral surface
3
a
of the annular flange
3
is fitted on the stepped portion
2
e
of the sintered cam pulley body
2
and then the tip of the annular projection
2
d
of the pulley body
2
is caulked by a caulking roller
9
which upsets the material of the projection to tightly join the flange
3
to the body
2
.
FIGS. 6 and 7
illustrate a main portion of a caulking equipment
4
using rollers for caulking the sintered, flanged cam pulley
1
shown in
FIGS. 4 and 5
.
FIG. 6
is a sectional showing a state before caulking in which the sintered, flanged cam pulley
1
is loaded into the caulking equipment
4
, and
FIG. 7
is a sectional view showing a state in which the sintered, flanged cam pulley loaded into the caulking equipment is being caulked.
As shown in
FIGS. 6 and 7
, the caulking equipment
4
using rollers are provided with a caulking head
5
and a jig
6
, the caulking head
5
being threadedly connected with a lower end portion of a cylinder
7
. Three to five caulking rollers
9
(two being shown in
FIGS. 6 and 7
) are mounted to a lower portion of the caulking head
5
at equal intervals in the circumferential direction, the caulking rollers
9
being supported rotatably on a roller support shaft
8
which extends in a direction perpendicular to the axis of the cylinder
7
. The jig
6
, which supports the sintered cam pulley body
2
, is provided with a protrusion
6
a
at a position aligned with the axis of the cylinder
7
.
FIG. 8
is a sectional view of the conventional caulking roller
9
used in the caulking equipment
4
shown in
FIGS. 6 and 7
.
FIGS. 9A and 9B
are sectional views for explaining how to caulk the sintered, flanged cam pulley
1
, using the conventional caulking roller
9
shown in FIG.
8
.
FIG. 9A
is a partially sectional view showing a positional relation between the caulking roller
9
before caulking and the sintered, flanged cam pulley
1
, and
FIG. 9B
is a partially sectional view of the sintered, flanged cam pulley
1
in a completely caulked state by the caulking roller
9
.
The following description is now provided about caulking the sintered, flanged cam pulley
1
by means of the caulking equipment
4
using rollers which is shown in
FIGS. 6 and 7
. First, the axial bore
2
c
with key way formed in the sintered cam pulley body
2
is fitted on the protrusion
6
a
of the jig
6
and then, using the key way, the pulley body
2
is set so as not to rotate with respect to the jig
6
. Subsequently, the inner peripheral surface
3
a
of the annular flange
3
is fitted on the stepped portion
2
e
of the sintered cam pulley body
2
. Next, with use of a drive unit (not shown), the caulking head
5
is brought down while allowing it to rotate about the axis of the cylinder
7
. As a result, the caulking rollers
9
in the caulking equipment come into abutment against end faces of the annular projection
2
d
of the sintered cam pulley body
2
. As the caulking head
5
is further brought down under rotation, the caulking rollers
9
, while rolling, cause the tip of the annular projection
2
d
to be upset or deformed plastically. As a result of this plastic deformation of the tip of the annular projection
2
d
, an excess metal portion is formed on both inner and outer periphery sides of the annular projection to complete the caulking work. In this way the annular flange
3
is fixed to the sintered cam pulley body
2
.
However, since the toughness of the sintered cam pulley body
2
is lower than that of carbon steel (S35C), if the amount of caulking is taken too large in an effort to obtain a high flange pressure output and a high flange loosening torque, there arises the problem that the caulked portion of the sintered cam pulley body
2
is separated or the problem that the annular projection
2
d
of the pulley body
2
is cracked. Moreover, if the amount of caulking is small, the flange pressure output is low, making it impossible to obtain a predetermined performance, or the annular flange
3
becomes loose and rotates. In the conventional caulking work, therefore, the caulking quantity control range is narrow and production control is very difficult for obtaining a satisfactory performance of the sintered, flanged cam pulley
1
.
The term “flange pressure output” as referred to herein represents a maximum load imposed axially on the sintered cam pulley body
2
corresponding to disengagement of the annular flange
3
from the pulley body. The term “flange loosening torque” represents a maximum torque imposed circumferentially on the annular flange
3
corresponding to loosening of the annular flange with respect to the sintered cam pulley body
2
.
In caulking the annular flange to the sintered pulley body, other sintered flanged pulleys than the sintered, flanged cam pulley
1
described above also involve the same problems as above.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to solve the above-mentioned problems of the prior art and provide a caulking roller capable of attaining a high flange pressure output and a high flange loosening torque and capable of widening the caulking quantity control range, as well as to provide a sintered flanged pulley caulked by such caulking roller.
For achieving the above-mentioned object, in the first aspect of the present invention there is provided a caulking roller for caulking an annular flange to a sintered pulley body, the caulking roller having a first conical surface of a first angle and a second conical surface of a second
Okabe Isamu
Uotani Kenichi
Dann Dorfman Herrell and Skillman
Hartmann Gary S.
Skillman Henry H.
Tsubakimoto Chain Co.
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