U.S. patent application number 10/787559 was filed with the patent office on 2004-10-07 for one-piece joint body.
Invention is credited to Degen, Guido, Ernst, Eberhard, Schiemenz, Wolfgang, Schmitt, Rainer.
Application Number | 20040197219 10/787559 |
Document ID | / |
Family ID | 7697339 |
Filed Date | 2004-10-07 |
United States Patent
Application |
20040197219 |
Kind Code |
A1 |
Degen, Guido ; et
al. |
October 7, 2004 |
One-piece joint body
Abstract
The invention relates to a method for producing a metal
component, in particular an internal joint part of a Cardan joint,
which is provided with a ball path. According to the invention: a
charge cavity is filled with powder; the charge cavity is delimited
by means of a die, at least one molding mandrel and a charging
mandrel positioned opposite the latter, a central mandrel and at
least one lower and upper punch; the powder is compressed in the
charge cavity by pressure on the upper and/or lower punch to form a
green product, which is then expelled and sintered
Inventors: |
Degen, Guido; (Wachtberg,
DE) ; Schiemenz, Wolfgang; (Bad Bruckenau, DE)
; Ernst, Eberhard; (Eichenzell, DE) ; Schmitt,
Rainer; (Wachtberg, DE) |
Correspondence
Address: |
WOODCOCK WASHBURN LLP
ONE LIBERTY PLACE, 46TH FLOOR
1650 MARKET STREET
PHILADELPHIA
PA
19103
US
|
Family ID: |
7697339 |
Appl. No.: |
10/787559 |
Filed: |
February 26, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10787559 |
Feb 26, 2004 |
|
|
|
PCT/EP02/09229 |
Aug 17, 2002 |
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Current U.S.
Class: |
419/28 |
Current CPC
Class: |
B22F 2998/00 20130101;
B22F 3/164 20130101; F16D 2003/22309 20130101; B30B 15/028
20130101; F16D 2003/22313 20130101; F16D 3/223 20130101; F16D
2300/12 20130101; B30B 15/022 20130101; B22F 3/03 20130101; B22F
2003/248 20130101; F16D 2250/00 20130101; B22F 2003/033 20130101;
B22F 2003/241 20130101; B22F 2003/166 20130101; B22F 2998/00
20130101; B22F 3/17 20130101; B22F 5/10 20130101 |
Class at
Publication: |
419/028 |
International
Class: |
B22F 003/24 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2001 |
DE |
101 42 805.7 |
Claims
What is claimed:
1. A process for the manufacture of a metallic sintered part, in
particular an internal joint part (3) of a cardan joint (1), which
is provided with a ball path (7), whereby a charge cavity (28) is
filled with powder, the charge cavity (28) is delimited by means of
a die (27), at least one molding mandrel (22) and a charging
mandrel (23) positioned opposite the latter, a central mandrel
(26), and at least one lower and upper punch (24, 25); the powder
is compressed in the charge cavity by pressure on the upper and/or
lower punch (24, 25) to form a green product, which is then
expelled and sintered.
2. The process according to claim 1, characterized by the fact,
that for the charging process, the charging mandrel (23) runs into
the die (27) in a charging position, and the lower punch is
maintained in a charging position. During the pressing procedure,
the molding mandrel that is attributed to the charging mandrel (23)
runs into the die (27), whereby the molding mandrel (22) pushes the
charging mandrel downward in the die (27) and the ball paths are
thereby shaped in powder through the geometry of the molding
mandrel (22). At the same time, the upper punch runs into the die
until at upper punch pressing position, and the powder is
compressed to the green product whereby ball paths (7) are created
through the geometry of the die. The lower punch runs into the die
until at lower punch (24) pressing position and also the powder is
compressed. The upper punch (25) and molding mandrel (22) extend
from the die (27) and the central mandrel (26) is withdrawn from
the green product (3) during the discharge procedure.
3. The process according to claim 1, characterized by the fact,
that the side of the charging mandrel (23) in the charging
position, which is turned towards the molding mandrel (22), flushes
with the top side (30) of the die (27) and the top side of the
central mandrel (26), that the molding mandrel (22) in the charging
positions is positioned at the top side (31) of the charging
mandrel (23) and pushes these back. At the same time pressure is
exercised on the upper punch (25), which runs into the die (27),
and afterwards the upper punch (25) and molding mandrel (22) extend
from the die (27) and the newly pressed green product (3) is
expelled from the die (27) through the lower punch (24).
4. The process according to claim 1, characterized by the fact,
that the powder is compressed to a green product through pressure
and heat.
5. The process according to claim 1, characterized by the fact,
that the die and at least on punch (24, 25) is heated up during the
pressing.
6. The process according to claim 1, characterized by the fact,
that the shape of the ball paths (7) is created by the molding
mandrel (27).
7. The process according to claim 1, characterized by the fact,
that the shape of the ball paths (7) is formed by the molding
mandrel (22) and the die (27).
8. The process according to claim 1, characterized by the fact,
that the surface of the ball paths (7) is compressed after
sintering.
9. The process according to claim 1, characterized by the fact,
that the surface of the ball paths (7) is compressed at least by a
one ball (32) after sintering, the pressure is exercised vertically
onto the ball path surface, whereby the compression can occur in
cold and hot conditions.
10. The process according to claim 9, characterized by the fact
that the ball (32) at least once compresses at least a partition of
the ball path (7)
11. The process according to claim 1, characterized by the fact,
that the readymade sintered component (3) is subsequently forged,
whereby the sintered component (3) is inserted in the die (27) on a
central mandrel (26) by means of ball paths (7), a forging tool of
the same build for shaping the external outline of the sintered
component (3) presses, and is afterwards expelled.
12. The process according to claim 1, characterized by the fact,
that the readymade sintered component (3) is calibrated after
sintering or forging, whereby this component is inserted in the die
(27) on a central mandrel (26) by means of ball paths (7), a
calibration tool of the same build for shaping the external outline
of the sintered component (3) presses, and is subsequently
expelled.
13. A process for the manufacture of a metallic component, in
particular an internal joint part (3) of a cardan joint (1), which
is provided with a ball path (7). A molding blank is thereby
inserted in the die (27) on a central mandrel (26), a forging tool
of the same build for shaping the external outline of the molding
blank presses, and is afterwards expelled.
14. A fixture for the manufacture of metallic components, in
particular components made according to a sinter-metallurgic and/or
forging process, particularly an internal joint part of a cardan
joint (1), with ball paths (7), according to the process in
correspondence with claim 1, characterized by a pressing fixture
(21) with at least one molding mandrel (22) and at least one
charging mandrel (23) attributed to the molding mandrel (22), one
lower and one upper punch (24, 25) and one central mandrel (26),
which shape the charge cavity (28) and are radially enclosed by a
die (27).
15. The fixture according to claim 14, characterized by the fact,
that three molding mandrels (22) and three charging mandrels (23)
attributed to the latter are provided, which are run in cavities
(28) in the die (27).
16. The metallic component, in particular a component manufactured
according to a sinter-metallurgic and/or forging procedure,
particularly an internal joint part (3) of a cardan joint (1), with
ball paths (7) positioned on the external perimeter, manufactured
according to the process in correspondence with the process claim
24, characterized by the fact, that the sintered component is made
of one piece.
17. The metallic component, in particular a component manufactured
according to a sinter-metallurgic and/or forging procedure,
particularly an internal joint part (3) of a cardan joint (1),
according to claim 24characterized by the fact, that the ball paths
(7) are positioned in an angle towards the pressing axle (20)
and/or are curved towards the pressing axle (20).
18. The metallic component, in particular a component manufactured
according to a sinter-metallurgic and/or forging procedure,
particularly an internal joint part (3) of a cardan joint (1),
according to one of claim 24 characterized by the fact, that the
ball paths (7) are round-shaped.
19. The metallic component, in particular a component manufactured
according to a sinter-metallurgic and/or forging procedure,
particularly an internal joint part (3) of a cardan joint (1),
according to claim 24 characterized by the fact, that the ball
paths (7) are roughly elliptically shaped.
20. The metallic component, in particular a component manufactured
according to a sinter-metallurgic and/or forging procedure,
particularly an internal joint part (3) of a cardan joint (1),
according to claim 24 characterized by the fact, that the ball
paths (7) are shaped with multiple corners.
21. The metallic component, in particular a component manufactured
according to a sinter-metallurgic and/or forging procedure,
particularly an internal joint part (3) of a cardan joint (1),
according to claim 24 characterized by the fact, that the ball
paths (7) show a higher density in partitions, particularly in the
area of a ball path contact area (16, 16').
22. The metallic component, in particular a component manufactured
according to a sinter-metallurgic and/or forging procedure,
particularly an internal joint part (3) of a cardan joint (1),
according to claim 24 characterized by the fact, that the ball
paths (7) are heat-treated in partitions, particularly in the area
of a ball path contact area (16, 16').
23. The metallic component, in particular a component manufactured
according to a sinter-metallurgic and/or forging procedure,
particularly an internal joint part (3) of a cardan joint (1),
according to claim 24 characterized by the fact, that the ball
paths (7) are surface-treated in partitions, particularly in the
area of a ball path contact area (16, 16').
24. A metallic component, in particular a component manufactured
according to a sinter-metallurgic and/or forging procedure,
particularly an internal joint part (3) of a cardan joint (1),
according to claim 1.
Description
[0001] This application claims foreign priority under 35 U.S.C.
.sctn. 119 of Application No. PCT/EP02/09229 filed Aug. 17, 2002 in
PCT, which claims priority to German Application Number 101 42
805.7 filed Aug. 31, 2001.
BACKGROUND OF THE INVENTION
[0002] Cardan joints that consist of an internal and external joint
part are well-known. They primarily serve as the torsional moment
conversion between shafts that are subjected to much larger shifts
while in operation. The inclusion of axial shifts are thereby
possible as well.
[0003] An example for the conversion of the torsional moment
through shafts that are bent against one another, is the constant
velocity cardan joint. The latter belong to the category of Cardan
joints, the most common design of which is the universal joint. In
the case of the universal joint, the joint forks of both shafts are
connected by means of a pin. Essentially, simple universal joints
do not allow for small angular changes. Axial and radial
displacements of the shafts are not possible.
[0004] The constant velocity cardan joint avoids these
disadvantages. Contrary to the universal joints, similarly shaped
revolutions are produced on the drive side at uniform angular speed
by means of constant velocity cardan joints. The same is valid for
the torsional moments.
[0005] The cardan shaft is made of two joints and one intermediate
shaft. The intermediate shaft is mostly implemented as telescope
shaft in order to compensate for elongations. It is a condition for
a monotonous conversion that both joint forks are situated on one
level and, in the event that the angles of deflection at both joint
forks are the same sizes, at least in the most frequent situation
while in operation.
SUMMARY OF THE INVENTION
[0006] It is the objective of this invention to provide a process
and a fixture with which a metallic sintered part or forging, in
particular an internal joint part of a cardan joint can be
manufactured in a simplified and precise manner.
[0007] The invention solves this objective by means of the
characteristics named in the process, fixture and factual
claims.
[0008] According to the invention, a process was proposed for
producing a metallic sintered component or forging, in particular
an internal joint part of a Cardan joint, which is provided with a
ball path, whereby a charge cavity is filled with powder, the
charge cavity is delimited by means of a die, at least one molding
mandrel and a charging mandrel positioned opposite the latter, a
central mandrel, and at least one lower and upper punch; the powder
is compressed in the charge cavity by pressure on the upper and/or
lower punch to form a green product, which is then expelled and
sintered. Metallic sintered powder is introduced in the charge
cavity. The molding mandrel is pulled in until the charging
mandrel, and the geometry of parts is fixed through a relative
displacement of the tools against one another, and, subsequently,
the powder is compressed by pressure in the upper and/or lower
punch to form a green product. Upon driving back the upper punch
and the molding mandrel, the newly pressed green product is then
expelled and sintered from the compression fixture. In order to
achieve a higher density it is appropriate when the sintered part
is deformed warm or cold after the sintering process. A calibration
process after the sintering and/or forging is possible to obtain
lower tolerances and/or a partial compression. It is for example
advantageous to drum the ball paths of the internal joint part
coldly or, alternatively, to drum after the sinter forging.
[0009] Components that have been manufactured according to a
sinter-metallurgic process have the advantage that all the bodies
of the internal joint part form a high-strength structure that
demonstrates excellent material features and surface quality.
[0010] It was the intention of the advantageous design of the
invention that for the charging process, the charging mandrel runs
into the die in a charging position, the central mandrel runs into
the die in a charging position and the lower punch is maintained in
a charging position. During the pressing procedure, the molding
mandrel that is attributed to the charging mandrel runs into the
die, whereby the molding mandrel pushes the charging mandrel
downward in the die and the ball paths are thereby shaped in powder
through the geometry of the molding mandrel. At the same time, the
upper punch runs into the die until at upper punch pressing
position, and the powder is compressed to the green product whereby
ball paths are created through the geometry of the die. The lower
punch runs into the die until at lower punch pressing position and
also the powder is compressed. The upper punch and molding mandrel
extend from the die and the central mandrel is withdrawn from the
green product during the discharge procedure. The external outline
of the internal joint part, the inner race, is partially formed by
the die itself and partially by molding mandrels moving in the
pressing direction in the die. Depending on the geometry of the
internal joint part, at least two upper molding mandrels and two
lower charging mandrels, preferably three mandrels, which are
mounted in the die and are movable in the pressing direction, are
provided for.
[0011] In a particular advantageous design of the invention, the
plan is that the side of the charging mandrel in the charging
position, which is turned towards the molding mandrel, flushes with
the top side of the die and the top side of the central mandrel,
that the molding mandrel in the charging positions is positioned at
the top side of the charging mandrel and pushes these back. At the
same time pressure is exercised on the upper punch, which runs into
the die, and afterwards the upper punch and molding mandrel extend
from the die and the newly pressed green product is expelled from
the die through the lower punch.
[0012] Within the appropriate design of the invention, it is the
intention to compress the powder to a green product through
pressure and heat.
[0013] It is the intention of the particularly appropriate design
of the invention that the die and at least a punch is heated up
during the pressing.
[0014] Within the appropriate design of the invention, it is
planned that the form of the ball paths are shaped by the molding
mandrel.
[0015] Within a further appropriate design of the invention, it is
intended for the form of the ball paths to be shaped by the molding
mandrel and the die.
[0016] In an advantageous design of the invention, it is provided
that the surface of the ball paths is compressed after the
sintering procedure. The compression of the surface in order to
achieve a higher level of firmness can for instance take place
through drumming, whereby it is advantageous when solely partitions
of the ball path surface is compressed. It is appropriate if at
least the contact surface of the balls of the ball path surface is
compressed.
[0017] In a particular advantageous design of the invention, it is
intended that, following the sintering procedure, the surface of
the ball paths is compressed at least by means of a ball, which
exercises pressure vertically onto the ball path surface.
[0018] Within a further appropriate design of the invention, it is
the plan that at least once the ball compresses at least one
partition. It is appropriate if the ball, which is preferably made
of carbide, rolls at least once, particularly multiple times over
the surface to be compressed, so that the surface is gradually
compressed and deformed.
[0019] In an advantageous design of the invention, it is the
intention that the readymade sintered part is subsequently forged
whereby the sintered part is inserted in the die on a central
mandrel by means of ball paths, a forging tool presses the sintered
part for shaping purposes and for the external outline, and is
afterwards expelled.
[0020] Within a further appropriate design of the invention, it is
provided that the readymade sintered part is calibrated following
the sintering or forging procedure, whereby the sintered part is
inserted in the die on a central mandrel by means of ball paths, a
calibration tool presses the sintered part for shaping purposes and
for the external outline, and is afterwards expelled.
[0021] An addition solution of the task is stated through a fixture
for the manufacture of metallic sintered parts, in particular of an
internal joint part of a cardan joint, with ball paths, with a
pressing fixture, with at least one molding mandrel and at least
one charging mandrel attributed to a molding mandrel, an upper and
lower punch and a central mandrel that shape the charge cavity and
are radially surrounded by a die. Such a pressing fixture is
characterized by a simple sequence of operations. The pressing
procedure is cost-effective and primarily time-saving in comparison
to the known metal-cutting manufacture. As a result of this, it is
possible to manufacture a large quantity of internal joint parts in
short period of time. The die that encloses the charging and
molding mandrels intercepts the pressure that has a radial effect
on the molding mandrels.
[0022] In an advantageous design of the invention, it is the
intention that per three molding mandrels and three charging
mandrels attributed to these are planned, and which are run in
recesses in the die.
[0023] The charging and molding mandrels and the die itself that
are positioned in the cavities of the die altogether form the
external outline of the internal joint part, that based on its
geometrical design cannot be manufactured with the usual pressing
fixtures.
[0024] The task is further on solved by means of a metallic
sintered part, in particular the internal joint part of a cardan
joint, with ball paths positioned on the external perimeter,
whereby the sintered part is made of one piece. For reasons of
firmness and durability of the internal joint part, it is
advantageous to shape the latter in one piece and not to assemble
from two for instance pressing-technical easy to manufacture
components.
[0025] In an appropriate design of the invention, it is intended
that the ball paths are positioned in an angle towards the pressing
axle and/or curved towards the pressing axle. The internal joint
part is shaped with undercuts, cavities and profiles, preferably
with ball paths that are axially aligned and radially curved
towards the joint body axle, in other words, also towards the
pressing direction. The ball paths are hereby developed with track
ground and track sides and the internal joint part demonstrates a
geometry which enables it to press the internal joint part axially
and to withdraw it from the pressing fixture and forging fixture,
respectively.
[0026] In a further appropriate design of the invention, it is
intended that the ball paths are round-shaped.
[0027] In an advantageous design of the invention, it is provided
that the ball paths are roughly elliptically shaped. This
definition is particularly advantageous, since the balls only bear
on two points on the ball paths and results in only one contact
line on the ball path during the roll motion. This area is
presented as aforesaid, compressed advantageously and, if
necessary, heat and/or surface-treated.
[0028] In an appropriate design of the invention, it is intended
that the ball paths are constructed with multiple cornerss. Also
this design of the ball path offers the advantage, as is the case
for the roughly elliptical ball path, that the balls only show a
minor bearing area on the ball path and, as a result, the rolling
friction decreases and in particular the Hertzian stress can be
optimized.
[0029] In advantageous design of the invention, it is intended that
the ball paths will indicate a higher density in partitions,
particularly in the area of the ball contact surface.
[0030] In a further advantageous design of the invention, it is
intended that the ball paths are heat-treated in partitions,
particularly in the area of the ball contact surface. Such a
component features the advantage that the ball paths acquire a high
level of firmness. The component can for instance be heat-treated
at least in the area of the ball paths by means of inductive and
case hardenings.
[0031] In a particularly advantageous design of the invention, it
is intended that the ball paths are surface-treated in partitions,
especially in the area of the ball contact surface. The surface for
example can be treated in cold and warm conditions through shot
peening, plasmanitriding, nitrocarburazing, phosphatizing and
drumming in order to optimize the characteristics of the ball
contact surface purposefully.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The invention is portrayed in the drawings on the basis of
an embodiment of a constant velocity cardan joint. They show:
[0033] FIG. 1 A constant velocity cardan joint,
[0034] FIG. 2 a perspective view of a compression molding die for
an inner race,
[0035] FIG. 3 the compression molding die cut with run-in
Mandrels,
[0036] FIG. 4 the compression molding die in the charging
Position,
[0037] FIG. 5 the compression molding die in the pressing
Position,
[0038] FIG. 6 the compression molding die in the discharge
Position,
[0039] FIG. 7 an inner race in top view
[0040] FIG. 8 an inner race according to section A-A in FIG. 7
[0041] FIG. 9 an inner race with ball in cross-section
DESCRIPTION OF PREFERRED EMBODIMENTS
[0042] FIG. 1 illustrates a constant velocity cardan joint 1. It
also shows external joint part 2 and internal joint part 3.
External joint part 2 is connected to shaft 4, and internal joint
part 3 is connected to shaft 5. Shaft 4 and 5 form an
propulsion-output system. Interior joint part 3 is included in
external joint part 2. Balls 6 in ball paths 7 are thereby
positioned in such a way between external joint part 2 and internal
joint part 3, that balls 6 are directed against one another in ball
paths 7 when bending shafts 4, 5. The balls run thereby inevitably
in the mirror plane. The displayed form shows that the bending
angle is 0.degree. and the ball is situated on a level vertically
on the straight lines that were shaped by the axles of shafts 4 and
5. The alignment shows a cap ring 8 which retains the balls in the
ball paths. In the event that the axle drive shaft is turned, the
output shaft is transferred also in case of corresponding bending
within the possible limits with equal revolutions and torsional
moment. Cardan joint 1 has been sealed up outwards by means of
flexible seal 18.
[0043] Ball paths 7 can be positioned parallel or in an angle
towards the pressing axle (inner race axle 20).
[0044] It is further on possible that ball paths 7 are curved
towards the pressing axle (inner race axle 20). As a result,
radially curved ball paths 7 are a possibility whereby ball paths 7
are equipped with track ground 12 and track sides 13.
[0045] FIG. 2 shows a perspective view of a pressing fixture 21 for
inner race 3 (internal joint part), whereby pressing fixture 21
features three molding mandrels 22.1, 22.2, 22.3 and charging
mandrels 23.1, 23.2, 23.3 attributed to these. Furthermore, a lower
punch 24, upper punch 25, as well as central mandrel 26 are
provided. The punches 24, 25 and mandrels 22, 23, 26 are radially
enclosed by die 27. Die 27, which encloses charging and molding
mandrels 23, 22 intercepts the pressure that has a radial effect on
molding mandrel 22.
[0046] Molding mandrel 22 and charging mandrel 23 that is
attributed to the latter are run in cavities 28.1, 28.2 in die 27.
The charging and molding mandrels 23, 22 and die 27 itself, which
are positioned in cavities 28.1, 28.2 make out the external outline
of internal joint part 3 that based on its geometrical design
cannot be manufactured with usual pressing fixtures.
[0047] FIG. 3 demonstrates a perspective view of pressing fixture
21 whereby molding mandrel 22 has run into die 27. Molding mandrel
22 runs into die 27 during the pressing procedure, whereby molding
mandrel 22 pushes charging mandrel 23 downward in die 27, and
whereby ball paths 7 of inner race 3 are changed into powder by
means of the geometry of molding mandrel 22.
[0048] FIG. 4 shows compression molding die 21 in charging
position. It is intended that charging mandrel 23 runs into die 27
in a charging position for the charging procedure, that central
mandrel 26 runs into the die in charging position and that lower
punch 24 is maintained in charging position. Charge cavity 28 is
filled with sintered powder 29 in charging position, whereby charge
cavity 28 is delimited by die 27, the three molding mandrels 22.1,
22.2, 22.3 and charging mandrels 23.1, 23.2, 23.3 attributed to
these, central mandrel 26, as well as by lower and upper punch 24,
25. While in charging position, the side of charging mandrel 23
that is turned towards molding mandrel 22 remains at equal height
as top side 30 of die 27 and top side 31 of central mandrel 26.
[0049] Charging and molding mandrels 23, 22 and die 27 itself,
which are positioned in cavities 28 of die 27, form the external
outline of internal joint part 3 that on the basis of its
geometrical design cannot be manufactured with the usual pressing
fixtures.
[0050] FIG. 5 demonstrates compression molding die 21 in pressing
position. Molding mandrels 22 will run in until charging mandrels
23, whereby molding mandrel 22 pushes charging mandrel 23 downwards
in die 27 and, as a result, ball paths 7 of inner race 3 are
changed to powder through the geometry of molding mandrel 22. At
the same time, upper punch 25 is run in die 27 until an upper punch
pressing position so that the powder can be compressed to a green
product, and whereby ball paths 7 are created also by the geometry
of die 27. Lower punch 24 runs in until a lower punch position is
attained, whereby also the powder is compressed. Die 27, which
encloses charging and molding mandrels 23, 22, intercepts the
pressure that has a radial effect on molding mandrel 22. A
displacement of the tools relatively against one another during the
pressing procedure fixes the parts' geometry of inner race 3.
[0051] It is advantageous when the sintered powder is compressed to
a green product with the application of heat. For example, die 27
and at least punch 24, 25 can be heated up during the pressing.
[0052] FIG. 6 shows compression molding die 21 in discharge
position. Upper punch 25 and molding mandrel 22 are extended from
die 27 during the discharge procedure. Central mandrel 26 is
retracted from green product 3. Readymade pressed green product is
expelled from the die by means of lower punch 24.
[0053] Subsequently, green product 2 is sintered.
[0054] It is an advantage when the readymade sintered green product
3 is cold and hot deformed after the sintering procedure in order
to achieve a higher density. A calibration procedure after the
sintering and/or forging is possible to obtain lower tolerances
and/or a partial compression. It is for instance an advantage to
drum ball paths 7 of internal joint part 3 cold or, alternatively,
to drum after the sintering-forging. It is advantageous when only
partitions of the ball path surface is compressed whereby at least
contact area 16 of balls 32 of the ball path surface must be
compressed.
[0055] The compression of the ball path surface can for instance
occur as a result of the fact that the surface of ball paths 7 is
compressed by means of a ball after sintering, the pressure is
exercised vertically onto the ball path area, whereby the ball at
least one compresses at least a partition of ball path 7. It is,
however, advantageous if the ball, which preferably consists of
hard metal, roll multiple times across the area to be compressed so
that the surface can be gradually compressed and deformed.
[0056] It is an advantage if readymade sintered part 3 is
subsequently forged, whereby sintered part 3 is inserted in die 27
by means of ball path 7 onto central mandrel 26, a forging tool for
shaping the external outline presses sintered part 3, and,
subsequently, the latter is expelled.
[0057] It is also advantageous after the sintering and forging
procedure, when sintered part 3 is calibrated. Tools can be applied
for forging and calibrating purposes, which are roughly of the same
build as the aforesaid compression molding die 21.
[0058] It is also particularly possible to forge a regulinic
molding blank to an inner race 3 by means of the aforesaid forging
tool.
[0059] FIG. 7 demonstrates inner race 3 in a top view. Inner race 3
is made of one piece and, as a result, the firmness and durability
of inner race 3 is high. Ball paths 7 are positioned in an angle
towards the pressing axle (inner race axle 20). Inner race 3 shows
in each case ball paths 7 attributed to one another in pairs. Ball
paths 7 are axially aligned within the image plane and demonstrate
a radial bending 14. In each of ball paths 7 attributed to one
another in pairs, the curving 14 is opposed, in other words, ball
paths 7 run towards one another in an axial direction. Inner race
axle 20 runs vertically towards the image plane through the center
of inner race 3.
[0060] FIG. 8 shows inner race 3 according to section A-A in FIG.
7.
[0061] FIG. 9 demonstrates ball path 7 with a ball 32 in section.
Ball 32 shows a round geometry. Ball path 7 shows a geometry that
is roughly elliptical. Ball 32 runs on contact surface 16, 16' and
has two points of contact 17, 17' on ball path 7 at all times.
Every point of contact 17, 17' is situated on another track side
13, 13'. The points of contact 17, 17' are separated from one
another in angle 2.delta. from the center of the ball. This design
is particularly advantageous, since balls 32 are positioned only on
two points on ball path 7 and results in only one contact line on
ball path 7 during the roll motion. Thus, as balls 32 only have a
small bearing area on ball path 7, it decreases the rolling
friction. The curving of ball 32 and of ball path 7 are optimized
in such a way that the Hertzian stress is minimized. This area is
advantageously compressed and, if necessary, heat and/or surface
treated. Possible processes would be for instance inductive
hardenings, case hardenings, shot peening, plasmanitriding,
nitrocarburizing, phosphatizing and drumming in cold and hot
conditions.
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