Note: Descriptions are shown in the official language in which they were submitted.
CA 02590444 2007-05-31
SI/cs 041540W0
30. Mai 2007
Deep rolling head
The invention concerned is a deep rolling head used for
deep rolling radii and recesses that limit the bearing
seat - on the side - for main pins and crankpins on
crankshafts for motors in vehicles.
The deep rolling head is especially intended for deep
rolling split pin crankpins on crankshafts. Deep rolling
becomes difficult with split pin crankpins at the fillet.
The fillet adjoins both adjacent crankpins on a
crankshaft. The deep rolling tool is supported only on
one side by a section of the circumference and on both
sides at the following section, i.e. the fillet, when
rolling above the circumference of this type of split pin
crankpin. The deep rolling head is not only limited to
deep rolling split pin crankpins. It has also been
designed for deep rolling common main pins and crankpins
on crankshafts that are limited on both sides by radii
and recesses.
For example, a deep rolling unit for deep rolling
crankshafts is known from US 5,445,003 that is able to
deep roll split pin crankpins. It is equipped with two
deep rolling heads that support one another. They have
work rollers only on their opposite sides. This known
deep rolling unit can only be used for deep rolling the
exterior radii or recesses of the crankpin. This means,
that the fillet cannot be machined.
Therefore, there is a need for the invention described in
this document. The invention is intended for deep rolling
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radii or recesses of all types of main pins or crankpins
on crankshafts. In particular, the invention is intended
for deep rolling fillets of split pin crankpins, which
was not possible to do before using previous deep rolling
tools.
The invention concerns a deep rolling head having two
disc- or ring-shaped and cylindrical work rollers with
the same external diameter and almost similar axial width
parallel and at a mutual distance from one another in the
housing (9) of the deep rolling head and mounted so that
they can rotate at a common, horizontal rotational axis
in the housing of the deep rolling head, and having a
protrusion on their opposite borders that is peripheral,
rounded off, and increases the external diameter of each
work roller by a specified size, which also
simultaneously extends beyond the section - near to the
edge - of the axial width of the work roller.
Therefore, the borders are designed to engage in the
depressions of the recesses that are already present when
deep rolling recesses; or to roll a depression in the
radii when deep rolling radii on transitions. When
engaging or rolling with the section, the work roller
supports its axial width on the bearing seat. During
this, the deep rolling head is stabilised by itself since
deep rolling split pin crankpins over the border section
of the area of the bearing seat that is not bordering the
fillet either engages in a depression on the opposite
edge of the bearing seat or creates a depression when
deep rolling radii in which it is simultaneously placed
on the side. In this case, deep rolling heads cannot be
simultaneously supported as stated earlier. Due to the
geometric ratios, two deep rolling heads cannot work next
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to one another for the crankpins of a split pin
crankshaft that are adjacent and only adjoined by the
fillet. For this reason, it is beneficial to align the
two deep rolling heads at an axial distance from one
another. This allows the deep rolling forces to be taken
up by supporting rollers that lie opposite to the deep
rolling heads. The deep rolling tool consists of a deep
rolling head and a support roller head.
The axial width of the deep rolling head with both its
disc-shaped work rollers corresponds to the maximum width
of the bearing seat from oil collar to oil collar. A
limited, axial resilience of both work rollers can be
beneficial when adjusting to the production tolerances of
the bearing seat.
The design of the deep rolling head is more beneficial
when one of the two discs making up the work rollers has
a protruding ring flange on one side, while the other
disc has a protruding, cylindrical pin that are both
concentrically aligned to the common rotational axis of
both work rollers. In particular, the cylindrical pin in
the assembled deep rolling head of one work roller should
engage almost free of play into the ring flange of the
other work roller. Both work rollers can be adjoined with
screws or pins to allow for later detachment, or they can
be permanently adjoined with riveting.
By connecting the two work rollers at their centres, a
steady assembly can be made which can be easily stored in
the housing of the deep rolling head. The assembly is
between the exterior circumference of the ring flange and
the housing of the deep rolling head. This creates a
partner arrangement comparable with twin rollers used for
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buggies (pram). Both plain bearings and rolling bearings
are suitable for use.
Alternatively, the deep rolling head can be designed by
forming both work rollers out of ring discs which are
placed on the pins that protrude out of the wall of the
housinq of the deep rolling head. With this design, the
ring discs can be mounted to the bearing pin with simple,
known means so that they are free to rotate.
The work rollers are made of a high-strength, and in
particular, tempered material as is generally the case
when using common work rollers. If a plain bearing is
used for the work roller, the housing of the deep rolling
head or the part of the housing in which the work roller
is stored must be made of bronze.
Both work rollers of a deep rolling head will here-in-
after be referred to as exterior roller when alluding to
the main journal pin and as interior work roller when
placed at the adjacent crankpins of a split pin
crankshaft.
The deep rolling head can be used as follows when deep
rolling split pin crankpins:
lst Case: Two exterior and one interior recesses are
present on split pin crankpins of a split pin crankshaft
which limit the two adjacent bearing seats of the split
pin crankpin on both sides. The exterior recesses are
first deep rolled by two deep rolling heads that support
each other, as previously stated in US 5,445,003. The
deep rolling direction with the known deep rolling heads,
e.g. at a 35 angle to the crankshaft axis, is beneficial
since a specified resistance to fatigue can be reached.
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In the current case, the exterior work roller of the
invention-related deep rolling head only has guiding
properties and does not carry out any deep rolling
procedure in the fillet. The exterior curvature radius of
the exterior work roller does not touch the recess in the
fillet of the bearing seat. In addition, the external
diameter of the exterior work roller is reduced by at
least the engaging depth of the interior work roller
while deep rolling the fillet and by the corresponding
tolerances of the interior depression when prefabricating
the crankshaft. The exterior work roller rests in the
exterior recess in the remaining circumference section of
the split pin crankpin and ensures that the deep rolling
head maintains its correct, axial position. In this
circumference section of the intervention of the exterior
work roller, the deep rolling force acting on the deep
rolling head is reduced. While this is taking place, a
suitable deep rolling force, e.g. 10 kN, is being built
up in the fillet.
2nd Case: Interior and exterior recesses are present on
the split pin crankpins of the crankshaft. They limit the
bearing seat on the side. These recesses are deep rolled
simultaneously with the deep rolling head. In addition to
this, the deep rolling force is increased via the
circumference section of the bearing seat where the
fillet is, e.g. doubled. The split pin crankshaft must be
prefabricated as precisely as possible since a deep
rolling unit can only balance out the difference in depth
of the recesses to a minimum.
The external diameters of the two work rollers are the
same size in this case.
The following describes the tool with a design example.
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The following figures are schematic and not to scale.
- Fig. 1 Perspective figure of a section of a split pin
crankshaft.
- Fig. 2 Side view of a deep rolling head.
- Fig. 3 A cross-section of the deep rolling head
displayed in Fig. 2 III - III divided along line III -
III.
- Fig. 4 A few individual parts of the deep rolling head.
- Fig. 5 The situation before deep rolling radii on a
split pin crankpin.
- Fig. 6 The situation like in Fig. 5 with two installed
deep rolling heads.
- Fig. 7 Deep rolling details.
The split pin crankshaft 1 of Fig. 1 has a split pin
crankpin 2 with the two individual crankpins 3 and 4
which are connected to each other by a fillet 5,
illustrated by the curly arrow. The two crankpins 3 and 4
are both limited on the side by webs 7 and 8. This forms
the transitions as recess 6 between the crankpin 4 and
the web 8. Fig. 1 portrays the ratios on a split pin
crankshaft 1.
Two disc-shaped work rollers 11 and 12 are mounted so
that they can rotate around a common rotational axis 13
in the housing 9 of a deep rolling head. The cylindrical
disc of the work roller 12 has a protruding ring flange
15 on one side 14 which has been placed concentrically to
the rotational axis 13. A protruding cylindrical pin 17
on the opposing side 16 of the cylindrical disc of the
work roller 11 corresponds to the ring flange 15. The pin
is also concentrically aligned to the common rotational
axis 13. The cylindri.cal pin 17 engages inside the
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cylindrical flange in the assembled deep rolling head 10,
as seen in Fig. 3. The pin engages with very little play.
The work rollers 11 and 12 that are brought together in
this way are to be joined together with screws 18.
A plain bearing is located between the work roller 11 and
12 and the housing 9 of the deep rolling head 10 in the
current design example. The housing 9 is made of bronze
and has a bore 19. The ring flange 15 engages in the bore
19 with its exterior side 35.
As is already known, the crankpin 4 is supported by the
supporting rollers 20 when deep rolling the crankpin 4 as
it is seen in Fig. 2 and 3. Two supporting rollers 20 are
united in a support roller head. The deep rolling head
and the support roller head make up the deep rolling
unit.
The protrusion 21 in Fig. 4 indicates the design of the
borders 22 of both work rollers 11 and 12. The borders 22
of both work rollers 11 and 12 are identical in their
design.
Fig. 5 shows the situation of deep rolling two crankpins
3 and 4 with two deep rolling heads 10 and 23 which are
both identical in design. The outside border 22 of the
work roller 12 is rounded off and enlarges the external
diameter of each disc of the respective work roller 11
and 12 by a specified size 24. The border 22 also extends
beyond a section 25 - which is on the edge - of an axial
width of each work roller 11 and 12. In the current
design example, both work rollers 11 and 12 have the same
axial width. This is not necessarily required. Different
widths are also possible. The total width of a deep
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rolling head 10 or 23 spans from the oil collar 26 of a
crankpin 3 or 4 to the oil collar 31 of the fillet 5. The
exterior recesses 29 are intended to be transitions
between the crankpin 3 or 4 to the respective webs 27 via
the oil collar 26. The borders 22 of the work rollers 11
and 12 engage in the exterior recesses 29 of the
crankpins 3 and 4 while deep rolling. The size 24 is
reduced to the value 0, i.e. on the predominant section
of their axial width, the work rollers 11 and 12 support
themselves on the bearing seats 36 of the respective
crankpins 3 or 4 as is seen in Fig. 5. The borders 22 of
the exterior work rollers 12 that engage in the exterior
recesses 29 leave behind rolling depths 32 in the
exterior recess 29 of the respective webs 27. The
internal borders 33 and 34 create rolling depths 30
within the fillet 5 corresponding to the borders 22.
Fig. 6 shows the situation in a deep rolling machine (not
shown) where two deep rolling heads 10 and 23 machine the
exterior recesses 29 of two adjacent crankpins 3 and 4 of
a crankshaft 1. The work rollers 11 and 12 are opposite
one another by 180 in relation to the main rotational
axis 35 of the crankshaft 1 Two supporting rollers are
opposite each work roller 11 and 12. The supporting
rollers are aligned in a support roller head 37. The
circumference section 38 of the illustrated fillet 5
which is hatched since it is cut is machined by the
border 33 of the interior work roller 11 while the
circumference section 39 is machined by the border 34 of
the interior work roller 11 on the left part of Fig. 6.
Fig. 7 depicts a situation where only one deep rolling
head 10 or 23 is seen. In its axial width 37, the deep
rolling head 23 extends beyond the axial width 38 of the
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bearing seat 36 and its recess 28 of the split pin
crankpins 3 and 4. The recess 39 of the fillet 5 is also
always rolled when deep rolling the split pin crankpins 3
and 4.
Reference drawing list
1 Split pin crankshaft
2 Split pin crankpin
3 Crankpin
4 Crankpin
Fillet
6 Recess
7 Web
8 Web
9 Housing
Deep rolling head
11 Work roller
12 Work roller
13 Common rotational axis
14 Side of work roller 11
Cylindrical ring flange-{}-
16 Side of work roller 12
17 Cylindrical pin
18 Screws
19 Bore
Support rollers
21 Protrusion
22 Border
23 Deep rolling head
24 Increase in border
Section on the edge
26 Oil collar
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27 Web
28 Transition radius
29 Exterior recess
30 Rolling depth
31 Oil collar of fillet
32 Rolling depth
33, 34 Interior border
35 Main rotational axis
36 Bearing seat
37 Support roller head
38 Circumference section
39 Circumference section
SI/cs 091540W0
