Note: Descriptions are shown in the official language in which they were submitted.
CA 02460681 2006-09-28
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METHOD OF MANUFACTURING FRICTION PLATE FOR WET CLUTCH
BACKGROUND OF THE INVENTION
F'TELD OF THE INVENTION
The present invention relates to a method of manufacturing
a friction plate for a wet clutch.
DESCRIPTION OF THE RELATED ART
There is such a conventionally known friction plate
including an annular core plate and friction members bonded to
opposite annular flat surfaces of the annular core plate, each
friction member comprising a plurality of friction member segments
disposed on the annular flat surface, an oil groove being provided
between adjacent friction member segments.
In this case, to bond the plurality of friction member
segments to the annular flat surface of the annular core plate,
a method is adopted which includes steps of subjecting a
band-shaped friction member material to a punching treatment to
form friction member segments and bonding the friction member
segments one by one to the annular flat surface (for example, see
Japanese Patent Application Laid-open Nos. 7-151175 and 6-
300051).
With the conventional method, however, there is a problem
that the yield in the fabrication of the friction member segments
is low, resulting in a poor economy.
SUMMARY OF THE INVENTION
Accordingly, it is an object of an embodiment of the
present invention to
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provide a method of manufacturing a friction plate of the
above-described type for a wet clutch, which has a good
productivity, wherein the yield in the fabrication of the
friction member segments can be increased, and the degrees
of freedom of the width and shape of oil grooves can be
increased.
According to the present invention, there is
provided a method of manufacturing a friction plate for a
wet clutch which includes an annular core plate and a
friction member bonded to at least one of annular flat
surfaces of the annular core plate, each friction member
comprising a plurality of friction member segments disposed
on the annular flat surface, an oil groove being provided
between adjacent friction member segments, wherein the
following steps are adopted to bond the plurality of
friction member segments simultaneously to the annular flat
surface of the annular core plate: a step of making at
least one continuous slit in at least one band-shaped
friction member material in a lengthwise direction to form a
plurality of friction member strips; a step of enlarging the
distance between the friction member strips to an amount
corresponding to the oil grooves formed between adjacent
friction member strips; a step of cutting off a portion of a
tip end of at least one of the friction member strips which
are located at opposite ends of the friction member material
to thereby provide the oil grooves between the friction
member segments on the annular flat surface; and a step of
superposing friction member segment correspondence portions
forming the tip ends of the plurality of friction member
strips to the annular flat surface of the core plate having
an adhesive applied thereto, and cutting the friction member
segment
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correspondence portions away from the remaining portions of the
friction member strips.
If the above means is adopted, the cutting for forming the
friction member strips, the cutting-off for securing the oil
grooves and the cutting-away of the friction member segment
correspondence portions from the remaining portions of the
friction member strips can be carried out using cutting edges,
respectively. Thus, when the friction member segments are
fabricated from the friction member strips, scraps produced can
be limited to those produced by the cutting-off, to thereby
increase the yield in the fabrication of the friction member
segments.
The width of each of the oil grooves can be changed freely
by changing the distance between the adjacent friction member
strips, and the shapes of the oil grooves can be also changed by
changing the shapes of the cuts in the formation of the friction
member strips. Moreover, the plurality of friction member
segments are bonded simultaneously to the core plate, which is
effective for improving the productivity for the friction plate.
BRIEF DESCRIPTION OF HE )RA WTNC~.S
Fig.1 is a plan view of a friction plate according to the
present invention.
Fig.2 is a sectional view taken on line 2-2 in Fig.l.
Fig.3 is a plan view of an essential. part of a band-shaped
friction member material.
Fig.4 is a plane view showing a state in which a plurality
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of friction member strips have been formed from the band-shaped
friction member material.
Fig.5 is a plan view showing the relationship between the
plurality of friction member strips and a distance-defining
member.
Fig.6 is a plan view showing the relationship between the
core plate and the plurality of frictiori member strips.
Fig.7 is a plan view showing a state in which a portion of
a tip end of one friction member strip has been cut off.
Fig. 8 is a plan view showing a state :Ln which friction member
segment correspondence portions of the friction member strips have
been superposed on the core plate.
Fig.9 is a plan view showing a state in which the friction
member segment correspondence portions have been cut away from
the remaining portions of the friction member strips.
Fig.10 is a plan view showing a state in which the core plate
has been rotated through 36 .
Fig.11 is a plan view showing a state in which a portion
of a tip end of one friction member strip has been cut off.
Fig.12 is a plan view showing a state in which the friction
member segment correspondence portions of the friction member
strips have been superposed on the core plate.
Fig.13 is a plan view showing a state in which the friction
member segment correspondence portions have been cut away from
the remaining portions of the friction member strips.
Fig. 14 is a plan view showing a state in which, when changing
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the widths of the plurality of friction member segments, the
friction member segment correspondence portions of the friction
member strips have been superposed on the core plate.
Fig.15 is a plan view showing a state in which, when changing
the widths of oil grooves, the friction member segment
correspondence portions of the friction member strips have been
superposed on the core plate.
Fig.16 is a plan view showing a state in which, when using
two friction member strips, a portion of a tip end of each of the
friction member strips has been cut off.
Fig.17 is a plan view showing a state in which, when using
two sets of friction member strips, each set comprising two
friction member strips, a portion of a tip end of each of the
friction member strips has been cut off.
Fig.18 is a plan view showing a state in which, when using
a plurality of friction member strips having corrugated cuts made
therein, friction segment correspondence portions thereof have
been superposed on the core plate.
Fig. 19 is a plan view showing a state in which friction member
segment correspondence portions of a plurality of friction member
strips have been superposed on a core plate to form segment groups
each including a plurality of arrow-fe.ather-shaped friction
segments in a modified shape.
Fig.20 is a plan view showing a state in which, when using
two different types of band-shaped friction member materials,
friction member segment correspondence portions of the two types
of pluralities of friction member strips have been alternately
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superposed on a core plate.
Fig.21 is a plan view showing a state in which, when forming
a friction member on one side by one run of a bonding operation,
a plurality of assemblies of friction member segment
correspondence portions each comprising a plurality of friction
member strips have been superposed on a core plate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figs. 1 and 2, a friction plate 1 for a wet clutch
includes an annular core plate 2 made of a metal, and a friction
member 4 formed from a fiber component, an additional component,
a binder and the like and bonded to at least one annular flat surface
3 of the annular core plate 2, e.g., to opposite annular flat
surfaces 3 in the preserlt embodiment. Each. of the friction members
4 comprises a plurality of friction member segments disposed on
the annular flat surface 3. In the present embodiment, each of
the friction members 4 comprises ten sets of segment groups G,
each of which comprises a single triangular friction member segment
-a and five rectangular friction member segments b- arranged in a
clockwise direction in Fig.1 from the seqment a. An oil groove
is provided between the adjacent friction member segments _a and
orb,and12.
To manufacture each of the friction members 4, the plurality
of friction member segments a and 12, namely, the segments of one
group G are bonded simultaneously to the one annular flat surface
3 of the annular core plate 2, and the same bonding operation is
then repeated nine times.
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The manufacture of the friction plate 1 will be described
in detail.
(a) A single band-shaped friction member material 6 is delivered
from a friction member material roll (not shown) , as shown in Fig.3.
In this case, a tip end edge of the friction member material 6
is formed in advance into an arcuate shape, so that it is
substantially matched to an outer peripheral edge of the core plate
2.
(b) Five cuts are made in a lengthwise direction in the
band-shaped friction member material 6, as shown in Fig.4, using
a cutter (not shown) comprising a plurality of, e.g., five (in
the embodiment) slitters arranged in parallel, thereby forming
six friction member strips 7. The cutter is not limited to the
one comprising slitters.
(c) As shown in Fig.5, the friction member strips 7 are passed
through six through-bores 9 formed in a distance-defining member
8, whereby a distance corresponding to the oil groove 5 is formed
between the adjacent friction member strips 7, and this state is
maintained.
(d) As shown in Fig.6, when tip ends of the six friction member
strips 7 reach the vicinity of an outer peripheral surface of the
annular core plate 2 placed on a turn table (not shown), the
movement of the friction member strips 7 is stopped.
(e) As shown in Fig.7, a portion of at least one of the friction
member strips 7 which are located at opposite ends, namely, the
one at a left end in Fig.7, is cut off obliquely over the entire
width (width: a circumferential length of the core plate 2) by
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a cutting edge of a cutter (not shown), to thereby secure an oil
groove 5 between such a portion and the rectangular friction member
segment 12 on the annular flat surface 3. This produces a
trapezoidal scrap 10.
(f) As shown in Fig.8, one friction member segment
correspondence portions 7a formed by the above-described
cutting-off and five friction member segment correspondence
portions 7b of an original shape are superposed on the annular
flat surface 3 of the core plate 2 having an adhesive applied
thereto, the portions 7a and 7b forming tip ends of the six friction
member strips 7.
(g) The friction member segment correspondence portions 7a and
7b are retained by a retaining member of a cutter (not shown),
and cut away from the remaining portions of the friction member
strips 7 by a cutting treatment along the outer peripheral edge
of the core plate 2, thereby providing one segment group G
comprising a single triangular friction member segmenta formed
by the above-described cutting-off and five rectangular friction
member segments 12 having the original shape.
(h) As shown in Fig.10, the core plate 3 is rotated through 36
in a counterclockwise direction.
(i.) As shown in Fig.11, a portion of the tip end of the friction
member strip 7 located at a left end is cut off obliquely over
the entire width, as at the step (e) in Fig.7.
(j) As shown in Fig.12, the friction member segment
correspondence portions 7a and 7b of the six friction member strips
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7 are superposed on the annular flat surface 3 of the core plate
2 having the adhesive applied thereto, as at the step (f) in Fig. 8.
(k) As shown in Fig.13, the friction member segment
correspondence portions 7a and 7b are retained by the retaining
member, and the friction member strips 7 are subjected to a cutting
treatment along the outer peripheral edge of the core plate 2 by
the cutting edge, as at the step (g) in Fig.9, thereby providing
a second segment group G comprising a single triangular friction
member segment a and five rectangular friction member segments
12.
Thereafter, the steps (h) to (k) in F:igs.10 to 13 are repeated
eight times to form a friction member 4 on one side, and
subsequently, the formation of a friction member 4 on the other
side is carried out by the same way.
If the cutting for forming the friction member strips 7,
the cutting-off for securing the oil grooves 5 and the cutting-away
of the friction member segment correspondence portions 7a and 7b
from the remaining portions of the friction member strips 7 are
carried out using the cutting edge, as described above, the
produced scraps 10 can be limited to those produced by the
cutting-off in fabrication of the friction member segments a and
12 from the band-shaped friction member material 6, whereby the
yield in the fabrication of the frictiori member segments -a and
b- can be increased.
The other embodiments will be described below.
In an embodiment shown in Fig.14, the width (the
circumferential length) of each of five rectangular friction
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member segments 12 in each of segment groups G is larger at a location
more apart from the triangular friction member segment.d. This
is achieved by changing the width of the friction member strip
7.
In an embodiment shown in Fig.15, the width (circumferential
length) of an oil groove 5 between a triangular friction member
segment a and a rectangular friction mernber segment 12 adjacent
thereto in each of segment groups G is smallest, and the width
of each of the other grooves 5 is larger at a location more apart
from the triangular friction member segment a. This is achieved
by changing the distance between the adjacent friction member
strips 7.
In an embodiment shown in Fig. 16, two friction member strips
7 are used, and a portion of each of tip ends of the friction member
strips 7, namely, an outer corner is cut off to secure an oil groove
5, whereby two triangular scraps 10 are produced. In this case,
two friction member segment correspondence portions 7b form two
rectangular friction member segments 12, which form one segment
group G. The two friction member strips 7 correspond to ones at
opposite ends in the plurality of strip-=shaped frictions.
In an embodiment shown in Fig.17, a friction member 4 is
divided into an outer peripheral half 4A and an inner peripheral
half 4B. The formation of the outer peripheral half 4A is carried
out using two friction member strips 7, and the formation of the
inner peripheral half 4B is carried out using two friction member
strips 7. In this case, a portion of a tip end of each of the
friction member strips 7 is cut off to secure an oil groove 5,
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as in the embodiment shown in Fig.16. However, the above-
described cutting-off and the cutting-away of each friction member
segment correspondence portions 7b in the formation of the inner
peripheral half 4B are carried out on the core plate 2 using the
cutting edge.
In an embodiment shown in Fig.18, corrugated cuts are
provided in order to form friction member strips 7 for forming
segments other than a triangular friction member segment -a, whereby
each of oil grooves 5 excluding oil grooves 5 on opposite sides
of the triangular friction member segment a obtains a winding shape.
The winding oil grooves 5 obstruct the discharge of an oil, and
hence the clutch is easy to release, leading to a reduction in
drag. In this case, one segment group G comprises a single
triangular friction member segment a, two deformed friction member
segments _Q having one side curved in an S-shape, and three S-
shaped deformed friction member segments !J. In Fig.18, 7c and 7d
are friction member segment correspondence portions.
In an embodiment shown in Fig.19, each of deformed friction
member segments.e excluding a triangular friction member segment
-a is formed into an arrow-feather-shape, so that a face turned
radially inwards is a V-shaped concave face 11, and a face turned
radially outwards is a V-shaped convex face 12. The deformed
friction member segments -e each having the arrow-feather-shape
obstruct the discharge of the oil and hence, the drag of the clutch
is reduced. In Fig.19, 7e is a friction member segment
correspondence portion.
In an embodiment shown in Fig.20, two types of friction
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member strips 7 and 14 formed of two d:i.fferent types of band-
shaped friction member materials 6 and 13 are used, and one type
of triangular and rectangular friction member segments a and b
and the other type of rectangular friction member segments I are
alternately disposed on each of flat annular surfaces 3. Such a
friction plate 1 is demanded, for example, in a wet clutch disclosed
in Japanese Patent Application Laid-open No. 2-3716. In Fig.20,
14f designates a friction member segment correspondence portion.
An embodiment shown in Fig.21 corresponds to a modification
of the embodiments shown in Fig.1 to 13. More specifically, six
friction member strips 7 constitute one assembly A. Friction
member segment correspondence portions 7a. and 7b in ten assemblies
A are equally disposed on one of annular flat surfaces 3 of a core
plate 2, and ten segment groups G are bonded simultaneously.
Therefore, a friction member 4 on one side is formed by one run
of a bonding operatiorl. If such a means is adopted, the accuracy
of the positions of the segment groups G can be enhanced easily.
The friction plate 1 according to the present invention may
be a friction plate including a friction member 4 on only -one of
annular flat surfaces 3 of a core plate 2.
Although the embodiments of the present invention have been
described in detail, it will be understood that the present
invention is not limited to the above-described embodiments, and
various modifications in design may be made without departing from
the subject matter of the invention defined in the claims.
