U.S. patent application number 12/954214 was filed with the patent office on 2011-03-24 for nut assembly and method for the production the same.
This patent application is currently assigned to Neumayer Tekfor GmbH. Invention is credited to Ewald Baechle, Manfred VOGEL.
Application Number | 20110070052 12/954214 |
Document ID | / |
Family ID | 34964489 |
Filed Date | 2011-03-24 |
United States Patent
Application |
20110070052 |
Kind Code |
A1 |
VOGEL; Manfred ; et
al. |
March 24, 2011 |
Nut Assembly and Method for the Production the Same
Abstract
A nut assembly comprised of a nut body (1a) and a pressure disk
(2a) and a method for producing the same. The nut body has a drive
portion, such as a polygonal portion, for engaging with a tool and
an abutment region that can be brought into contact with the
supporting surface of the pressure disk arranged on the nut body in
a non-releasable manner. The pressure disk has a central opening
into which a neck formed on the nut extends axially at least in
part, and the neck has a projection which radially overlaps or
engages the thrust ring in order to form the non-releaseable
connection.
Inventors: |
VOGEL; Manfred;
(Kappelrodeck, DE) ; Baechle; Ewald; (Hausach,
DE) |
Assignee: |
Neumayer Tekfor GmbH
Hausach
DE
|
Family ID: |
34964489 |
Appl. No.: |
12/954214 |
Filed: |
November 24, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11547674 |
Jul 24, 2007 |
7862440 |
|
|
PCT/DE2005/000612 |
Apr 6, 2005 |
|
|
|
12954214 |
|
|
|
|
Current U.S.
Class: |
411/427 |
Current CPC
Class: |
F16B 37/00 20130101;
F16B 41/002 20130101; F16B 43/00 20130101; F16B 23/0061 20130101;
Y10T 29/49948 20150115; F16B 39/16 20130101; B21K 1/702
20130101 |
Class at
Publication: |
411/427 |
International
Class: |
F16B 37/04 20060101
F16B037/04 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 7, 2004 |
DE |
10 2004 016 979.9 |
Claims
1. A nut assembly comprising an assembled nut body and a pressure
plate which are rotatable relative to each other, said nut assembly
having a drive portion for engaging a tool, and a contact region
which can be brought into contact with a support surface of a
pressure plate non-releasably arranged on the nut body, said
pressure plate having a central aperture into which a neck formed
integrally on the nut body axially extends at least partially,
wherein in order to form the non-releasable connection the neck has
an extension which partially overlaps or engages behind the
pressure ring, and wherein the pressure plate is formed of a steel
having a higher carbon content than 34 CrMo.sub.4.
2. A nut assembly according to claim 1, wherein the pressure plate
has been brought to its final form by a single forming operation
before assembly with the nut body.
3. A nut assembly according to claim 1, wherein said drive portion
comprises a polygonal body.
4. A nut assembly comprising an assembled nut body and a pressure
plate which are rotatable relative to each other, said nut assembly
having a drive portion for engaging a tool, and a contact region
which can be brought into contact with a support surface of a
pressure plate non-releasably arranged on the nut body, said
pressure plate having a central aperture into which a neck formed
integrally on the nut body axially extends at least partially,
wherein in order to form the non-releasable connection the neck has
an extension which partially overlaps or engages behind the
pressure ring, and wherein the pressure plate is composed of 42
CrMo.sub.4.
5. A nut assembly according to claim 4, wherein the pressure plate
has been brought to its final form by a single forming operation
before assembly with the nut body.
6. A nut assembly according to claim 4, wherein said drive portion
comprises a polygonal body.
7. A nut assembly assembled from a nut body and a pressure plate
which are rotatable relative to each other, said nut assembly
having a drive portion for engaging a tool and a contact region
which can be brought into contact with the pressure plate arranged
un-releasably on the nut body, said pressure plate having a central
aperture into which a neck formed integrally on the nut body
axially extends at least partially, wherein the neck comprises an
extension which partially radially overlaps or engages behind the
pressure ring, and wherein the drive portion of the nut body
comprises fewer than six or six or more than six force engaging
elements, and insofar as the drive portion has six force engaging
elements, these deviate from a standard hex.
8. A nut assembly according to claim 7, wherein said drive portion
comprises a polygonal body.
9. A nut assembly according to claim 7, wherein the drive portion
is a round exterior profile.
10. A nut assembly according to claim 7, wherein the drive portion
comprises eight force engaging elements.
11. A nut assembly according to claim 7, wherein the drive portion
comprises twelve force engaging elements.
12. A nut assembly according to claim 7, wherein the drive portion
has a Torx.RTM. profile.
13. A nut assembly according to claim 7, wherein the drive portion
of the nut assembly has an outer diameter and an inner diameter,
and the ratio of the outer diameter to the inner diameter is less
than 1.3.
14. A nut assembly according to claim 7, wherein the drive portion
of the nut assembly has an outer diameter and an inner diameter,
and the ratio of the outer diameter to the inner diameter of the
drive portion is less than 1.2.
15. A nut assembly according to claim 7, wherein before assembly of
the pressure plate with the nut body, the pressure plate is
deformed in a calibrated manner in a tool or immediately before an
assembly tool at least at the edge of the central opening which
during assembly could come into contact with the nut body.
16. A nut assembly according to claim 15, wherein a burr formed at
the edge of the central opening of the pressure plate is removed in
the calibrated deformation of the plate.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of application Ser. No.
11/547,674, now U.S. Pat. No. ______, which is the US national
stage of international patent application no. PCT/DE05/000612,
filed Apr. 6, 2005, and published in German on Oct. 20, 2005 as WO
2005/098246, the entire disclosure of which is incorporated herein
by reference. Priority is claimed based on Federal Republic of
Germany patent application no. DE 10 2004 016,979.9, filed Apr. 7,
2004.
BACKGROUND OF THE INVENTION
[0002] The invention relates to both nut assemblies and methods for
producing the same. The nut assemblies consist of a nut body and a
pressure disk. The nut body has a drive portion, e.g., a polygonal
portion, for engagement with a tool and an abutment region, which
can be brought into contact with the supporting surface of the
pressure disk arranged captively on the nut body when the nut is
tightened. The pressure disk has a central opening into which a
neck integrally formed on the nut body extends axially at least in
part. The neck has a projection for forming a captive connection,
which projection partially radially overlaps or engages the thrust
ring.
[0003] In this type of nut assemblies, disclosed, for example, in
German Laid Open Publications DE-OS 43 07 090 and 196 50 453 and
used particularly to fix wheels or rims to the axles of motor
vehicles, especially commercial vehicles, the pressure disk, is
produced by cold forming, subsequent turning and then hardening and
tempering prior to assembly with the nut body. The nut body itself
has a hexagonal drive portion, as specified in the DIN standard for
nuts.
SUMMARY OF THE INVENTION
[0004] One object of the present invention is to make the nut
assemblies cheaper to manufacture, to reduce and optimize the
number of manufacturing steps and, in addition, to reduce the use
of material. A further object is to increase the transmittable
torques while at the same time maintaining or improving the other
essential performance characteristics.
[0005] According to the invention, this object is attained at least
in part by eliminating the cold forming, turning and hardening and
tempering in the manufacture of the pressure disk and instead
bringing the pressure disk into its final form by a single forming
process prior to assembly with the nut body. According to another
feature of the invention, the forming process is a hot pressing
process, which can be carried out in a progressive die. The hot
pressing process according to the present invention is further
characterized in that it includes only a single heating process. It
can be particularly advantageous if cooling of the pressure disk
after hot forming is defined or controlled, so that the pressure
disk is cooled according to a specified time/temperature profile.
This makes it possible to produce a microstructure of the pressure
disk that is comparable to that obtained by a separate heat
treatment, such as "hardening and tempering," by simultaneous
cooling from the heating temperature used in the forming
process.
[0006] In a manufacturing process of this type, particularly when
the process according to the present invention is used to produce a
pressure disk, it is possible not only to eliminate cold forming
and turning but also hardening and tempering, which provides
substantial cost savings overall compared to conventional
manufacturing processes. Defined cooling may be accomplished by air
and/or at least a partial use of a liquid medium.
[0007] Defined cooling imparts properties similar to those obtained
by hardening and tempering, i.e., material strength comparable to
the tempering strength of the conventional production method, which
includes a separate hardening and tempering process, as well as the
corresponding microstructure. These properties, which are at least
approximately equivalent to hardening and tempering, are thus not
achieved by an additional heating process but during cooling from a
hot forming process, which is required for shaping in any case. As
already mentioned, the nut assembly according to the invention is
characterized in that it is not cold-formed, not machined in a chip
removing process and not subjected to a separate tempering
process.
[0008] Thus, according to the invention, after a heating process,
the following contours of the pressure disk: [0009] outside
diameter, [0010] the abutment region facing away from the nut body;
this region may also be concave and serves to contact the rim,
[0011] the central opening, including the contour thereof; the
contour serves to hold the pressure disk on the nut and may be
radially expanded, e.g., conically flared, toward the abutment
region of the pressure disk or may be formed as an undercut, [0012]
the supporting surface provided for contacting the nut body; the
supporting surface may be conical--convex--and the conicity thereof
may be steeper than that of the abutment region, [0013] the
junction area between the supporting surface and the outside
diameter, are obtained in a single forming process, i.e., by means
of a single heating step, in a progressive die, and defined cooling
achieves properties comparable to those obtained by hardening and
tempering.
[0014] It may be particularly advantageous if the pressure disk is
made of steel with a higher carbon content than the 34 CrMo.sub.4
conventionally used for such pressure disks, i.e., 42 CrMo.sub.4,
for example, which is not much more expensive than the former.
[0015] According to other features of the invention, nut assemblies
can be improved and at least some of the aforementioned objects of
the invention attained, i.e., for example, increasing the
transmittable torques, obtaining a more uniform contact pattern as
the nut is tightened and improving moment distribution, e.g., by
distributing the material more uniformly across the polygon. Costs
may also be reduced by reducing the use of material.
[0016] According to advantageous further refinements of the
invention, such nut assemblies can have fewer than six, six or more
than six force application elements, such as application
projections or surfaces. However, if the drive portion, i.e., the
nut body, has six force application elements, these elements
differ, according to one inventive feature, from a standard hexagon
specified by DIN for such nuts. Regardless whether fewer than six,
six or more than six force application elements are used, it may be
advantageous if the drive portion is a round external profile,
e.g., a hexagonal, octagonal or some other round external profile.
These round external profiles of the nut member may also take the
form of a Torx.RTM. profile or a Torx.RTM.-like profile. Torx.RTM.
profiles or Torx.RTM.-like profiles have thus far been used only in
combination with screws, i.e., with internal or external profiles
on the screw heads. The invention therefore also relates to nuts
with a round external profile, e.g., a Torx.RTM. or Torx.RTM.-like
profile, in general and nut assemblies in particular. Nuts
according to the invention with a round external profile or a
Torx.RTM. or Torx.RTM.-like profile are characterized in that they
do not have straight sides connecting the individual axially
extending corner edges but round edges with radial indentations or
axially extending grooves therebetween. Compared to comparable
polygonal profiles, these profiles offer substantially greater
torque transmission, reduce the radial forces and improve the
engagement of tools because the resulting contact pattern during
tightening is substantially more uniform. This shape improves
centering of the tool because e.g., all six elements are actually
bearing elements. This is not the case in a standard hexagon
configuration where the tool is usually centered along only two or
three surfaces.
[0017] If, for instance, an octagonal round external profile is
used instead of a hexagonal round external profile, it is possible
not only to achieve the above-described advantages but also to save
on the cost of material because in that case the outside diameter
can be further reduced while maintaining at least approximately
identical characteristics, since the ratio of outside diameter to
inside diameter of the drive portion may be set at less than 1.3
according to the invention, e.g., between less than 1.3 and 1.18,
so that even less material is required than for the standard
comparable Torx.RTM..
[0018] It may be particularly advantageous if a nut assembly,
especially one of the above-described type, has a dodecagonal
configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention will now be described in greater detail with
reference to FIG. 1 through 8, in which:
[0020] FIG. 1 is a sectional view of a nut assembly according to
the prior art taken along line I-I of FIG. 2;
[0021] FIG. 2 is a top view of the nut assembly of FIG. 1;
[0022] FIG. 3 is a sectional view of a nut assembly according to
the invention taken along line of FIG. 4;
[0023] FIG. 4 is a top view of the nut assembly of FIG. 3;
[0024] FIG. 5 illustrates another nut assembly according to the
invention in a sectional view taken along line V-V of FIG. 6;
[0025] FIG. 6 is a top view of the nut of FIG. 5;
[0026] FIG. 7 shows another exemplary embodiment according to the
invention in a sectional view taken along line VII-VII of FIG. 8,
and
[0027] FIG. 8 is a top view of the nut of FIG. 7.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0028] Conventional nut assemblies corresponding to FIGS. 1 and 2,
which are also described in German Laid Open Publication 196 50
453, have a nut body 1 with a captive pressure member 2 attached
thereto. The nut body has a drive portion configured as a hexagon 3
for engagement with a tool. The nut body 1 furthermore has an
abutment surface 4, which is brought into contact with the
supporting surface 5 of the captive pressure disk 2 on the nut body
when the nut is tightened. This pressure disk has a central opening
6 into which a neck 7 integrally formed on the nut body extends
axially, at least in part. To form a captive connection, the neck
has a projection 8 in the form of an expansion 11, which partly
radially overlaps or engages the thrust ring.
[0029] First, the pressure disk 2 is produced by cold forming prior
to assembly with the nut body 1. Subsequently, at least the
supporting surface 5 and the abutment region 9, with which the
pressure disk contacts the rim, are turned. Finally, the pressure
disk, which in the prior art consists of 34 CrMo.sub.4, is hardened
and tempered. After assembly of the pressure disk 2 and the nut
body 1, the neck 8, which initially has a smaller diameter than the
central opening, is widened radially outwardly and the pressure
disk is thereby secured to the nut body.
[0030] Identical or equivalent parts or contours shown in FIGS. 3
to 8 are provided with the same basic reference numerals.
[0031] The pressure disk 2a, 2b and 2c shown in FIGS. 3 to 8 are
formed of steel having a higher carbon content, preferably 42
CrMo.sub.4, than the pressure disk according to the prior art
depicted in FIGS. 1 and 2. These pressure disks 2a, 2b and 2c are
brought into their final form using a single forming process,
preferably a hot pressing process, and preferably in a progressive
die. The hot pressing process includes a single heating step. After
hot forming, the pressure disk is cooled in a defined or controlled
manner according to a predetermined time-temperature profile. This
defined cooling from the heating temperature used in the forming
process produces a microstructure of the pressure disk which is
comparable to that obtained by "hardening and tempering." This can
be achieved by controlled cooling by air or by at least partial use
of a liquid medium.
[0032] During the forming process, the present contours of the
pressure disk, i.e., [0033] the outside diameter 10, [0034] the
abutment region 9 facing away from the nut body, with which the
pressure disk contacts the rim and which may also be conical, i.e.,
concave, [0035] the central opening 6 including its contour 11,
which is radially expanded toward the abutment region 9 of the
pressure disk 2 to hold the pressure disk on the nut, [0036] the
supporting surface 5 provided for contact with the nut body, which
is conical or convex and the conicity of which is steeper than the
conicity that may be provided on the abutment region 9, [0037] the
junction area between the supporting surface 5 and the outside
diameter 10, are produced in a single forming process, i.e., by
means of a single heating step, and in a progressive die. By
defined cooling after or even in the forming die, it is possible to
achieve performance characteristics that are comparable to those
obtained by hardening and tempering.
[0038] According to a further refinement of the invention, for
which FIGS. 3 to 8 are shown as an example, the nut body 1
according to FIG. 3 is formed with six force application elements
12a in the form of a round external profile. This is a
"Torx".RTM.-type or a modified or similar profile.
[0039] The nut body according to FIGS. 5 and 6 has eight force
application elements 12b in the form of a round external profile.
The ratio of outside diameter A.sub.b to core diameter B.sub.b is
smaller than the ratio in the embodiment depicted in FIGS. 3 and 4,
i.e., less than 1.3. In FIGS. 3 and 4, the ratio of outside
diameter A.sub.a to core diameter B.sub.a is approximately
1.35.
[0040] In FIGS. 7 and 8 the force application elements 12c are
configured as a dodecagon and the ratio of outside diameter A.sub.c
to core diameter B.sub.c is less than 1.2.
[0041] In a further step according to the invention, prior to
assembly with the nut body the pressure disk is calibrated in a
tool, or directly in front of an assembly tool, at least along edge
13 of the central opening which could come into contact with the
nut body when the nut is tightened, but at least a bur that may
have been created there is deformed.
[0042] The foregoing description and examples have been set forth
merely to illustrate the invention and are not intended to be
limiting. Since modifications of the described embodiments
incorporating the spirit and substance of the invention may occur
to persons skilled in the art, the invention should be construed
broadly to include all variations within the scope of the appended
claims and equivalents thereof.
* * * * *