U.S. patent application number 10/818247 was filed with the patent office on 2004-09-30 for shifting arm.
This patent application is currently assigned to INA-Schaeffler KG. Invention is credited to Doppling, Horst, Schubel, Rainer, Seuferling, Stephan, Werner, Stefan.
Application Number | 20040187623 10/818247 |
Document ID | / |
Family ID | 7701381 |
Filed Date | 2004-09-30 |
United States Patent
Application |
20040187623 |
Kind Code |
A1 |
Seuferling, Stephan ; et
al. |
September 30, 2004 |
Shifting arm
Abstract
A shifting arm for transmitting shifting movements is a formed
part which is formed without cutting from a thin sheet. It includes
a mouth recess in from an edge of the sheet, and stop faces are
formed along the edges of the recess and out of the plane of the
sheet.
Inventors: |
Seuferling, Stephan;
(Hochstadt, DE) ; Doppling, Horst;
(Herzogenaurach, DE) ; Werner, Stefan; (Neustadt,
DE) ; Schubel, Rainer; (Aurach, DE) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
|
Assignee: |
INA-Schaeffler KG
|
Family ID: |
7701381 |
Appl. No.: |
10/818247 |
Filed: |
April 5, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10818247 |
Apr 5, 2004 |
|
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PCT/EP02/10915 |
Sep 28, 2002 |
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Current U.S.
Class: |
74/469 |
Current CPC
Class: |
Y10T 74/20582 20150115;
Y10T 74/20 20150115; F16H 63/32 20130101; F16H 2063/322 20130101;
F16H 2063/327 20130101 |
Class at
Publication: |
074/469 |
International
Class: |
B65H 029/66 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 4, 2001 |
DE |
101 48 980.3 |
Claims
What is claimed is:
1. A sheet-metal shifting arm for transmitting shifting movements,
the shifting arm is a formed part which is formed from a thin sheet
without cutting the sheet.
2. The shifting arm as claimed in claim 1, wherein the sheet has a
thickness of up to 2 mm in its initial state before the forming of
the shifting arm.
3. The shifting arm as claimed in claim 1, wherein the material of
the shifting arm is a deep-drawing steel.
4. The shifting arm as claimed in claim 1, wherein the material of
the shifting arm is a low-alloy deep-drawing steel.
5. The shifting arm as claimed in claim 1, wherein a shifting
element is connected to the shifting arm by a welding process; the
shifting element is moveable with respect to a longitudinal center
axis thereof.
6. The shifting arm as claimed in claim 5, wherein the shifting
element is a shifting rod which is displaceable along its
longitudinal center axis and is pivotable about its longitudinal
center axis.
7. The shifting arm as claimed in claim 5, wherein the shifting
element is a shifting fork.
8. A sheet-metal shifting arm for transmitting shifting movements,
wherein the shifting arm is a formed part which is formed without
cutting from a thin sheet, the arm has a recess which is open in
the shape of a mouth toward one edge of the shifting arm, wherein
the mouth is for the engagement of a shifting finger.
9. The shifting arm as claimed in claim 8, wherein the recess is at
least partially bounded by at least two stop faces which lie
opposite each other and face each other.
10. The shifting arm as claimed in claim 8, wherein the at least
two stop faces lie plane-parallel opposite each other, face each
other and are formed without cutting of the sheet; the sheet having
at least one angled section out of the plane of the sheet and the
step faces being formed on the at least one angled section of the
sheet.
11. The shifting arm as claimed in claim 8, wherein the recess is
bounded at least partially by at least two stop faces which lie
plane-parallel, are opposite each other, face each other and are
formed without cutting of the sheet; the sheet having at least one
angled section out of the plane of the sheet and the step faces
being formed on the angled sections of the sheet; the distance
between the stop faces lying opposite each other, has an accuracy
which permits a deviation from the desired value of the distance of
at maximum {fraction (1/10)} mm, and the distance is set by
machining of the sheet without cutting.
12. The shifting arm as claimed in claim 8, wherein the recess is
at least partially bounded by at least two stop faces which lie
opposite each other, face each other and are formed without cutting
of the sheet; at least one of the stop faces on at least one side
adjoining a body edge of the sheet, the sheet adjoining the body
edge where the sheet is rounded without cutting of the sheet.
13. The shifting arm as claimed in claim 8, wherein the recess is
at least partially bounded by at least two stop faces, which lie
opposite each other, face each other and are formed without cutting
of the sheet; the sheet having at least one angled section out of
the plane of the sheet; the shifting arm having at least one body
edge which delimits the stop face on at least one side to form a
lateral face of the shifting arm, and the body edge has a chamfer
that is formed on it without cutting of the sheet.
14. The shifting arm as claimed in claim 8, wherein the recess is
at least partially bounded by at least two stop faces, which lie
opposite each other, face each other and are formed without
cutting; the sheet having at least one angled section out of the
plane of the sheet; the shifting arm having at least one body edge
on the angled section which delimits the stop face on at least one
side to form a lateral face of the shifting arm, and the body edge
has a chamfer formed on it without cutting of the sheet; a distance
describing the chamfer in a cross section of the shifting arm
between an edge, which bounds the stop face at a side toward the
chamfer, and an imaginary common cut edge which extends parallel to
the edge of the stop face and is extended beyond the chamfer, the
imaginary common cut edge together with the lateral face of the
shifting arm has an accuracy which permits a deviation from the
desired value of the distance of a maximum {fraction (1/10)}
mm.
15. A sheet-metal shifting arm for transmitting shifting movements,
wherein the shifting arm is a flat formed part which is formed from
a thin sheet without cutting of the sheet, the formed part having
one end in a fork-shape, the one end having two prong-shaped
projections and having at least one edge which is formed by an
angled section out of the plane of the sheet, each of the
projections having at least one stop face on the angled section
having another stop face on the other of the projections, the faces
lie opposite each other.
16. The shifting arm as claimed in claim 15, wherein the shifting
arm has at least one tab leading off from the shifting arm,
enabling the shifting arm to be connected to a shifting element by
at least one weld on the tab.
17. The shifting arm as claimed in claim 15, wherein the shifting
arm includes at least one formation of the sheet that is of
bead-shape.
18. A sheet-metal shifting arm for transmitting shifting movements,
wherein the shifting arm has a bracket-shape and the arm is formed
from a thin sheet without cutting of the sheet; the shifting arm
having a first wall section with a recess opening therein in the
shape of a mouth opening toward one edge of the shifting arm, and
the opening being adapted for engagement of a shifting finger; the
recess being at least partially bounded by at least two stop faces,
which lie opposite each other, face each other and are formed
without cutting of the sheet; the sheet having angled sections out
of the plane of the sheet in which the stop faces are formed; the
sheet including three further wall sections which are angled out of
the plane of the sheet and angled out of the first wall section and
which projects in the same direction out of the plane, and the
first wall section merging integrally into the three further wall
sections.
19. The shifting arm as claimed in claim 18, wherein the three
further wall sections are formed integrally with one another.
20. The shifting arm as claimed in claim 18, wherein the three
further wall sections are bent off from the first wall section, and
the three further wall sections are brought together so that each
two of the further wall sections are fastened to each other.
21. The shifting arm as claimed in claim 18, wherein the shifting
arm includes at least one formation of the sheet that is of bead
design.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This is a continuation of International Application
PCT/EP02/10915 published in the German language and claiming
priority from German Application No. 101 48 980.3, filed Oct. 4,
2001.
FIELD OF THE INVENTION
[0002] The invention relates to a sheet-metal shifting arm for
transmitting shifting movements.
BACKGROUND OF THE INVENTION
[0003] Shifting arms of this type are arranged fixedly on shifting
elements, such as shifting shafts or shifting forks. The shifting
shafts sit displaceably and/or pivotably in the transmission. The
shifting forks sit, for example, displaceably and/or pivotably on a
shifting rail. The shifting elements are displaced and/or pivoted
by means of a shifting finger or an actuating element of similar
design. The actuating element engages in a shifting mouth or cutout
of similar design on the shifting arm and transmits shifting
movements to the shifting element. Locking cylinders or the like
also frequently engage in the shifting mouth and prevent
gear-shifting errors.
[0004] The forces acting on the shifting arm by means of the
shifting movements are very high, in particular in the case of
shifting errors. In the past, shifting arms of the prior art have
therefore been produced predominantly from metal plate or strip
material. Thick starting material was also required in order to
make the stop faces, which are formed in the shifting mouth and are
intended for the shifting fingers, large enough.
[0005] The shifting arms are, as a rule, punched parts. The stop
faces for the shifting fingers lie, as a rule, opposite each other
in the shifting mouth of a shifting arm. Their distance from each
other and alignment with respect to each other have to be realized
with very high accuracy. Similarly, very exacting requirements are
placed on the dimensional accuracy of other, further functional
faces in the shifting mouth, for example functional faces for the
engagement of a locking cylinder. The required accuracies for the
functional dimensions, such as for the distance between the stop
faces lying opposite each other in the shifting mouth, and
functional faces, such as for the chamfers, which bound the
shifting mouth and are required for the gentle introduction of the
shifting finger into the shifting mouth, and roundings on body
edges, can, as a rule, only be obtained by a material-removing
finishing operation. Some functional faces are too rough for a
frictional contact with the shifting finger due to the punching
outline along the cut edge of the parts after punching has taken
place, and therefore also have to be finished with a
material-removing operation.
[0006] The use of material for the production of the shifting arms
is relatively high. The shifting arms are relatively heavy on
account of their solid construction and limits are placed on their
design due to the material thickness of the starting material. For
the above-mentioned reasons, the production of the shifting arms is
very cost-intensive particularly in large-series and mass
production.
[0007] FR 27 62 659 shows a shifting arm of the generic type. A
shifting arm produced from metal plate is fastened to a shifting
fork. This shifting arm has a shifting mouth. The wall of the
shifting arm is reinforced in the region of the shifting mouth in
order to provide stop faces of sufficient width.
SUMMARY OF THE INVENTION
[0008] It is therefore the object of the invention to provide a
shifting arm which does not have the above-mentioned
disadvantages.
[0009] This object is achieved according to the invention by the
shifting arm being a formed part which is formed from a thin sheet
without cutting the sheet. The advantages of a shifting arm
according to the invention in comparison with the prior art reside
in the low costs for production, particularly in large-series and
mass production. The consumption of material for the production of
a shifting arm of this type is low. The weight of this shifting arm
is reduced by up to 50% in comparison with the shifting arms
described at the beginning. The thin material permits virtually
unlimited designs. Use is made of forming processes without
cutting, in particular processes for the cold-forming of sheets,
such as rolling, drawing, stamping and punching. The required
accuracies for functional dimensions, such as for the distance of
the stop faces lying opposite each other in the shifting mouth, and
functional faces, such as for the positioning and dimensioning of
chamfers and roundings for the gentle introduction of the shifting
finger in the shifting mouth, is, as a rule, obtainable only by the
forming process or forming processes. Material-removing machining
is unnecessary, as a rule.
[0010] Sheets having a thickness of the starting material of up to
2 mm in limit cases of up to 2.5 mm, are preferably used for the
production of the shifting arms according to the invention. Sheets
of St35, Ck45, C35 and low-alloy deep-drawing steels, such as
16MnCr5, and all weldable and further formable steels and
deep-drawing steels can be used as the material. In the selection
of the material, account also has to be taken, in accordance with
the different applications, of its welding suitability together
with the hardening requirements. The shifting arms are preferably
fastened by welding to shifting elements, such as shifting rods and
shifting forks. The stop faces, in particular, have a hard surface.
For this purpose, the shifting arms according to the invention are
subjected to edge-layer hardening in the region of the switching
mouth by means of induction hardening processes. It is also
conceivable, for cost reasons, to harden the entire shifting arm or
the shifting arm welded to the shifting element as one unit. In
this case, case-hardening processes or through-hardening processes
can be used, depending in each case on the type of steel used.
[0011] The object of the invention is furthermore achieved by the
shifting arm being a formed part which is formed from a thin sheet
without cutting and has a recess open in the shape of a mouth
toward one edge of the shifting arm, for the engagement of a
shifting finger. The recess is used to provide the shifting mouth
on the shifting arm for the engagement of the shifting finger. The
shifting mouth is provided, for example, by a cutting-out step in a
multi-stage forming process or by punching followed by stamping or
protrusion of the edges of the shifting mouth.
[0012] In a further refinement of the invention, stop faces for the
switching finger are provided with the edges of the recess being
protruded or by them being stamped. The sheet at the edges of the
recess is preferably protruded in such a manner that the sheet is
angled from or out of the plane of the actual flat base body of the
shifting arm, generally at right angles, but also at any other
desired angle, and as far as possible forms an edge hemming the
entire recess. The width of the edge is determined by the required
width of the stop faces, which are subsequently stamped onto the
edge or produced by means of sizing, and/or also as a function of
the demands placed on the stiffness of the shifting arm.
[0013] The stop faces for the shifting finger lie, as a rule,
opposite each other in the shifting mouth. Their distance from each
other and alignment with respect to each other have to be realized
with very high accuracy. Similarly, very exacting demands are
placed on the dimensional accuracy of other functional faces in the
shifting mouth, for example functional faces to rest a locking
cylinder against. These accuracies for the functional dimensions,
such as for the distance of the stop faces lying opposite each
other in the shifting mouth from each other and their alignment
with respect to each other, can be ensured, as a rule, without a
material-removing finishing operation. Provision is therefore made
by one refinement of the invention for the recess to be bounded at
least by two stop faces, which lie plane-parallel opposite each
other, face each other and are formed without cutting, on angled
sections of the sheet, the distance between the stop faces lying
opposite each other being realized, by machining without cutting,
with an accuracy which permits a deviation from the desired value
of the distance of at maximum {fraction (1/10)} mm. Functional
faces, such as the stop faces and such as the chamfers, which bound
the shifting mouth or the stop faces and are required for the
gentle introduction of the shifting finger into the shifting mouth,
and roundings on body edges, are introduced without cutting. The
surface of these functional faces is smooth and work-hardened on
account of the stampings or the sizing. The resistance to wear of
the faces is increased. Material-removing polishing is
unnecessary.
[0014] A further refinement of the invention makes provision for
the recess to be bounded at least by two stop faces, which lie
opposite each other, face each other and are formed without
cutting, on angled sections of the sheet. In this case, the
shifting arm has at least one body edge which delimits the stop
face at least at one side to form a further lateral face of the
shifting arm and has a chamfer formed on it without cutting. A
distance describing the chamfer in the cross section of the
shifting arm between an edge, which bounds the stop face towards
the chamfer, and an imaginary cut edge has an accuracy which
permits a deviation from the desired value of the distance of at
maximum {fraction (1/10)} mm. The imaginary cut edge is a common
cut edge, which is parallel to the edge, of the stop face, which is
extended beyond the chamfer, together with the further lateral face
of the shifting arm, which face is extended beyond the chamfer. The
distance of the edge, which separates the stop face from the face
produced by the chamfer, from the corner point of an imaginary,
unbroken body edge is therefore very precise and can be realized
more precisely than the distance brought about by material-removing
machining.
[0015] The object is furthermore achieved by the shifting arm being
a formed part which is formed without cutting from a thin sheet,
the formed part being designed in a fork-shaped manner at one end
and in this case being provided at the end with two prong-shaped
projections. The shifting arm also has at least one edge on its
outer contour that is formed by an angled sheet. Each of the
projections is provided, on a section which is angled from the
sheet of the shifting arm, at least with a stop face which lies
opposite a further stop face lying opposite on the other of the
projections. A shifting arm of this type can be produced with a
great saving on material and has a low weight. The design
possibilities are diverse.
[0016] With one refinement of the invention, provision is made for
the shifting arm to have at least one tab which is angled from the
shifting arm, and for the shifting arm to be connected to a
shifting element by means of at least one weld on the tab. The tab
is fastened to the shifting element by suitable welding processes,
such as laser welding, resistance welding or inert-gas arc
welding.
[0017] In one refinement of the invention, the shifting arm is
provided with at least one formation of bead-like design. To
prevent the shifting arm from buckling and to increase the
torsional rigidity, the shifting arm is provided on the different
wall sections in a manner corresponding to its purpose with one or
more beads or with laminations, stampings, protrusions of the sheet
or bending over of the sheet at the edges, which are produced
without cutting. Also very effective in this respect is an edge
which is peripherally reinforced as far as possible on the shifting
arm, which is essentially of flat design. This reinforced edge is
produced by a bead or by a sheet which is angled away at the edge
from the flat base body.
[0018] The invention makes provision, in particular for higher
loads, for the shifting arm to be a bracket-shaped formed part
which is formed without cutting from a thin sheet. In this case,
the shifting arm has a first wall section with a recess open in the
shape of a mouth toward one edge of the shifting arm, for the
engagement of a shifting finger. The recess is bounded at least by
two sections, which lie opposite each other and face each other and
are formed without cutting, on angled sections of the sheet. The
first wall section merges integrally into three further wall
sections which are angled from the first wall section and facing
the same direction. A refinement of the invention makes further
provision in this respect for the further three wall sections of
the shifting arm also to be formed integrally with one another. The
shifting arm is therefore formed by a deep-drawn part of
shell-shaped design. With another refinement, provision is made for
those wall sections of the shifting arm which are drawn to each
other in a flat sheet-metal blank to be bent off from the flat
blank, brought together and welded at the contact points in such a
manner that the sheet-metal part obtains a shell- or bracket-shaped
form.
[0019] Finally, provision is made with one refinement of the
invention for the shifting arm to have at least one formation of
bead-like design on at least one of the wall sections. To prevent
the shifting arm from buckling and to increase the torsional
rigidity, the shifting arm is provided on at least one or
individual or all of the different wall sections in accordance with
its use with one or more beads or with laminations, stampings,
protrusions of the sheet or bending over of the sheet at the edges,
which are produced without cutting.
[0020] Other features and advantages of the present invention will
become apparent from the following description of the invention
which refers to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The invention is explained in greater detail below with
reference to a number of exemplary embodiments, in which:
[0022] FIG. 1 shows an exemplary embodiment of a shifting arm
according to the invention in a perspective view,
[0023] FIG. 2 shows the shifting arm from FIG. 1 in the view from
the front,
[0024] FIG. 3 shows the shifting arm from FIG. 1 in a side view
sectioned along the line III-III according to FIG. 2,
[0025] FIG. 4 shows a partial view of the shifting arm according to
FIG. 1 in a sectional illustration along the line IV-IV according
to FIG. 2,
[0026] FIG. 5 shows an exemplary embodiment of a shifting arm
according to the invention which is of bracket-shaped design,
[0027] FIG. 6 shows the shifting arm from FIG. 5 in the view from
the front,
[0028] FIG. 7 shows the shifting arm from FIG. 5 in a side view
sectioned along the line VII-VII according to FIG. 6,
[0029] FIG. 8 shows a further exemplary embodiment of a shifting
arm according to the invention in its initial state before the wall
sections are brought together,
[0030] FIG. 9 shows the finished shifting arm according to FIG. 8
in the view from the front,
[0031] FIG. 10 shows the shifting arm according to FIG. 9 in a side
view, illustrated in section,
[0032] FIG. 11 shows a further exemplary embodiment of a shifting
arm of flat design,
[0033] FIG. 12 shows the shifting arm from FIG. 10, fastened to a
shifting element, and
[0034] FIG. 13 shows the shifting arm from FIG. 1, fastened to a
shifting element.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0035] FIGS. 1 to 4 illustrate a shifting arm. The shifting arm 1
is formed from a flat formed part which is formed without cutting
from a thin sheet of 2 mm. The formed part has a fork-shaped design
and has two prong-shaped projections 2 and 3. The projections 2 and
3 bound a recess 4. The recess 4 is partially bounded by four stop
faces 2a, 2b, 3a, 3b lying opposite one another. A shifting finger
(not illustrated) strikes against the stop faces 2a and 3a. The
stop faces 2b and 3b, which are designed lying opposite each other,
are, in a locking position, a stop for a locking cylinder or
locking pin (not illustrated). Each of the stop faces 2a, 2b, 3a,
3b is formed on a section 1b which hems the recess 4 and is angled
away from meaning out of the plane of the sheet or the plane of the
shifting arm 1 or of the projections 2 and 3. The stop faces 2a and
3a face each other and are aligned plane-parallel to each other.
The clear distance D between the stop faces 2a and 3a is realized,
by forming without cutting, with an accuracy which permits a
deviation from the desired value of the distance of at maximum
{fraction (1/10)} mm.
[0036] A body edge 5 which bounds the contour of the recess 4 on
one side delimits the stop faces 2a, 2b, 3a, 3b (FIG. 4) with
respect to a rear lateral face 6 of the shifting arm. At the height
of the stop faces 2a and 3a, the body edge 5 is rounded by the
forming process. The rounding has a radius which is smaller than
the wall thickness of the shifting arm 1 in the region of the stop
faces 2a and 3a. The stop faces 2a and 3a are delimited by a
further body edge 8 with respect to the other flat side of the
shifting arm 1, which side lies opposite the rear lateral face 6
and therefore the body edge 5 and has the front lateral face 7.
This body edge 8 has a chamfer 8a at least at the height of the
stop face 2a and a chamfer 8b at the height of the stop surface 3a.
The distance d.sub.1 describing the chamfer 8a in cross section
(FIG. 4) together with the angle a.sub.1 from the edge 8c to an
imaginary, common cut edge 9, which is aligned parallel to the edge
8c, is realized with an accuracy which permits a deviation of the
desired value of at maximum {fraction (1/10)} mm. The edge 8c
delimits the stop face 2a with respect to the chamfer 8a. The cut
edge 9 is a cut edge which would form an imaginary body edge not
broken by a chamfer, between the stop face 2a and the front lateral
face 7. The distance d.sub.2 describing the chamfer 8b in the cross
section (FIG. 4) together with the angle a.sub.2 from the edge 8d
to an imaginary, common cut edge 9a, which is aligned parallel to
the edge 8d, is, in the same manner as the distance d.sub.1
realized with an accuracy which permits a deviation of the desired
value of at maximum {fraction (1/10)} mm. In this case, the edge 8d
is an edge bounding the stop face 3a with respect to the chamfer
8b. The cut edge 9a is a cut edge which is aligned parallel to the
edge 8d and would form an imaginary body edge which was not broken
by a chamfer, between the stop face 3a and the front lateral face
7.
[0037] The contour of the shifting arm 1 is reinforced against
impermissible deformations under load by means of an edge 1a which
is formed from an angled sheet of the shifting arm 1. Furthermore,
the shifting arm 1 has a formation 10 which is of bead-like design
and likewise leads to a high rigidity of the sheet-metal part.
[0038] A tab 11 leads off from the shifting arm 1 and is provided
for fastening the shifting arm to a shifting element, which is
moveable with respect to its longitudinal center axis. FIG. 13
illustrates, for example, the manner in which the shifting arm 1 is
fastened to the guide eye 12a of a shifting fork 12 by means of the
tab 11. The tab 11 is bent in a rounded manner matching the shape
of the guide eye 12a and, bearing against the guide eye 12a, is
welded to the guide eye 12a.
[0039] A further exemplary embodiment of the invention is
illustrated in FIG. 5 to FIG. 7. A shifting arm 13 is a formed part
of thin sheet having a bracket-shaped design. The shifting arm 13
is formed from a first wall section 14 and three further wall
sections 15, 16 and 17. The three wall sections 15, 16 and 17,
which are formed integrally with the first wall section 14, lead
off from the first wall section 14 at right angles and facing in
the same direction and are also connected integrally to one another
at the corners 18 and 19. The wall section 15 functions as a
supporting plate of the shifting arm 13, on which the first wall
section 14 is supported, when subjected to a load exerted, for
example, by shifting fingers (not illustrated) via the wall
sections 16 and 17 functioning as asset plates. A tab 15a
protruding out of the wall section 15 is provided for securing the
shifting arm 13 on a shifting element (not illustrated), for
example a shifting fork or a shifting shaft. The first wall section
14 has a formation 20 which is of bead-like design and, like the
wall sections 16 and 17, results in a high rigidity of the
sheet-metal part.
[0040] The first wall section 14 is provided with a mouth-shaped
recess 14a which is open toward the free edge of the wall section
14. The recess 14a is hemmed on its peripheral edge 14b by a sheet
which is angled away from the flat wall section 14. Stop faces 14c
and 14d are formed, in each case without cutting, in the sheet of
the edge 14a. The stop faces 14c and 14d lie opposite each other on
the recess 14a and are aligned parallel to each other. The distance
D between the stop faces 14c and 14d is realized by cold-forming of
the sheet with an accuracy which permits a deviation of the
distance D from its desired value of at maximum {fraction (1/10)}
mm.
[0041] FIGS. 9 and 10 show an alternative design of a shifting arm
21 from the shifting arm according to FIG. 5. The shifting arm 21
is formed from a first wall section 22 and three further wall
sections 23, 24 and 25. FIG. 8 shows the unfinished shifting arm 21
in the form of a blank 28 which is partially formed at the shifting
mouth. The wall sections 23, 24 and 25, which are stretched out
flat in the plane of the wall section 22 on this blank 28, are
connected integrally to the wall section 22. On the finished
shifting arm 21 (FIG. 9 and FIG. 10) the wall sections 23, 24 and
25 are bent off from the first wall section 22 at right angles and
facing in the same direction. The wall sections 23 and 24 and 23
and 25 are respectively brought together and welded together at the
corners 26 and 27.
[0042] FIGS. 11 and 12 show a shifting arm 29. The shifting arm 29
is a formed part of essentially flat design and of thin sheet. The
shifting arm 29 is designed such that it is angled in its main
plane running into two limbs 30 and 31. The limb 30 is designed in
a fork-shaped manner at its free end and has two prong-shaped
projections 32 and 33. The projections 32 and 33 bound a recess 34.
The recess 34 is partially bounded by four stop faces 32a, 32b,
33a, 33b lying opposite one another, for a shifting finger (not
illustrated). The stop faces 32b and 33b, which are formed lying
opposite each other, are, in a locking position, a stop for a
locking cylinder or locking pin (not illustrated). Each of the stop
faces 32a, 32b, 33a, 33b is formed on a section 29a which hems the
recess 34 and is angled away from the sheet of the shifting arm 29.
The stop faces 32a and 33a face each other and their surface is
shaped in a manner such that it is slightly outwardly curved into
the recess 34 from the body edges 35 and 36 to the center of the
particular stop face 32a and 33a.
[0043] The contour of the shifting arm 29 is reinforced against
impermissible deformation under load by means of an edge 29b formed
from an angled sheet of the shifting arm 29. The shifting arm 29
furthermore has a formation 31a of bead-like design on the limb 31
and a bead-like formation 30a on the limb 30, which formations
likewise lead to a high rigidity of the sheet-metal part. A tab 31b
leads off from the shifting arm 29 and is provided for fastening
the shifting arm 29 to a shifting element, which is moveable with
respect to its longitudinal center axis.
[0044] FIG. 12 illustrates the manner in which the shifting arm 29
is fastened to a shifting rod 37 by means of the tab 31b, for
example. The tab 31b is bent in a rounded manner matching the shape
of the cylindrical outer surface area of the shifting rod 37 and,
bearing against the shifting rod 37, is welded to the shifting rod
37. A shifting fork 40 is fastened to the shifting rod 37. The
shifting rod 37 can be displaced along its longitudinal center axis
by means of bearings 38 and 39 and is mounted in a manner such that
it can pivot about its longitudinal center axis in a transmission
(not illustrated).
[0045] Although the present invention has been described in
relation to particular embodiments thereof, many other variations
and modifications and other uses will become apparent to those
skilled in the art. It is preferred, therefore, that the present
invention be limited not by the specific disclosure herein, but
only by the appended claims.
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