U.S. patent application number 10/478711 was filed with the patent office on 2004-08-05 for wiper blade.
Invention is credited to Hasenkox, Urlich, Klamt, Guido, Mueller, Lutz, Vogt, Andreas.
Application Number | 20040148728 10/478711 |
Document ID | / |
Family ID | 7685795 |
Filed Date | 2004-08-05 |
United States Patent
Application |
20040148728 |
Kind Code |
A1 |
Vogt, Andreas ; et
al. |
August 5, 2004 |
Wiper blade
Abstract
A wiper blade for a windshield wiper, in particular for a
windshield wiper of a motor vehicle, is proposed, which has a wiper
blade rubber with a wiper blade rubber lip (2). In order to achieve
a low dry friction coefficient, the wiper blade rubber lip (2) is
fabricated partially of polyethylene (FIG. 1).
Inventors: |
Vogt, Andreas; (Renningen,
DE) ; Mueller, Lutz; (Aichtal, DE) ; Hasenkox,
Urlich; (Ditzingen, DE) ; Klamt, Guido;
(Gerlingen, DE) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH, LLP
100 E WISCONSIN AVENUE
MILWAUKEE
WI
53202
US
|
Family ID: |
7685795 |
Appl. No.: |
10/478711 |
Filed: |
November 24, 2003 |
PCT Filed: |
April 12, 2002 |
PCT NO: |
PCT/DE02/01365 |
Current U.S.
Class: |
15/250.48 ;
428/515 |
Current CPC
Class: |
B05D 3/0254 20130101;
B05D 5/00 20130101; B05D 1/265 20130101; B05D 7/02 20130101; C08J
2321/00 20130101; B05D 1/06 20130101; B05D 5/08 20130101; Y10T
428/31909 20150401; C08J 7/046 20200101; B05D 1/24 20130101; C08J
2423/00 20130101; B60S 1/38 20130101; B60S 2001/3829 20130101; C08J
7/0427 20200101 |
Class at
Publication: |
015/250.48 ;
428/515 |
International
Class: |
A47L 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 23, 2001 |
DE |
101 25 045.2 |
Claims
1. Wiper blade for a windshield wiper, in particular for a
windshield wiper of a motor vehicle, with a wiper blade rubber,
which features a wiper blade rubber lip (2, 6), characterized in
that the wiper blade rubber lip (2, 6) is fabricated partially of
polyethylene.
2. Wiper blade according to claim 1, characterized in that the
wiper blade rubber lip (2) is coated with polyethylene (1).
3. Wiper blade according to claim 1 or 2, characterized in that a
head piece (3) is attached to the wiper blade rubber lip (2) via a
reversing bridge (4) and that the wiper blade rubber lip (2), the
reversing bridge (4) and the head piece (3) are coated with
polyethylene (1).
4. Wiper blade according to one of claims 1 through 3,
characterized in that the wiper blade rubber lip (2) is coated
partially with polyethylene (1).
5. Wiper blade according to one of claims 1 through 4,
characterized in that the wiper blade rubber lip (6) contains
polyethylene in volume.
6. Wiper blade according to one of claims 1 through 5,
characterized in that the polyethylene is a PE-UHMW.
7. Wiper blade according to one of claims 1 through 5,
characterized in that the polyethylene is a PE-HD.
8. Wiper blade according to one of claims 1 through 5,
characterized in that the polyethylene is a PE-X.
9. Process to manufacture a wiper blade for a windshield wiper,
which is comprised of a wiper blade rubber with a wiper blade
rubber lip, characterized in that the wiper blade rubber lip is
manufactured by vulcanizing a rubber material together with
polyethylene.
10. Process according to claim 9, characterized in that the
polyethylene is in powder form as a primary material and has a
grain size of less than 30 .mu.m.
11. Process according to claim 9 or 10, characterized in that the
rubber material is coated with the polyethylene before
vulcanization.
12. Process according to claim 11, characterized in that the rubber
material is coated with a dispersion containing polyethylene
particles.
13. Process according to claim 11, characterized in that the
polyethylene is applied to the rubber material in accordance with
an electrostatic powder coating process.
14. Process according to claim 11, characterized in that the
polyethylene is applied to the rubber material by means of a
fluidized bed.
15. Process according to claim 11, characterized in that the rubber
material and the polyethylene are combined with one another in
accordance with a co-extrusion process.
16. Process according to one of the claims 11 through 15,
characterized in that the rubber material coated polyethylene is
exposed to purging air.
17. Process according to claim 9 or 10, characterized in that the
wiper blade rubber lip is manufactured of a mixture, which is
comprised of the rubber material and the polyethylene.
18. Process according to claim 17, characterized in that the
mixture contains between 1% and 50% polyethylene powder.
Description
STATE OF THE ART
[0001] The invention starts with a wiper blade for a windshield
wiper, in particular for a windshield wiper of a motor vehicle, in
accordance with the type defined in more detail in the
pre-characterizing clause of Patent Claim 1 as well as a process to
manufacture a wiper blade in accordance with the type defined in
more detail in the pre-characterizing claim of Patent Claim 7.
[0002] A wiper blade of the type cited at the outset is known from
practice and is comprised of a wiper blade rubber, which is
embodied with a wiper blade rubber lip. The wiper blade rubber or
the wiper blade rubber lip is composed of a rubber material, which
is manufactured on the basis of natural rubber, for example.
[0003] Wiper blade rubbers or wiper blade rubber lips of known
wiper blades have the disadvantage that they have relatively high
dry friction coefficients .mu..sub.tr when they are applied to a
glass of a conventional windshield.
[0004] These types of dry friction coefficients, which lie between
0.8 and 1.2 and are higher than the friction coefficients that
occur with a wetter windshield, require powerful and therefore
costly windshield wiper drives.
ADVANTAGES OF THE INVENTION
[0005] The wiper blade, in accordance with the invention for a
windshield wiper, in particular for a windshield wiper of a motor
vehicle, with the features in accordance with the
pre-characterizing clause of Patent Claim 1, in which the wiper
blade rubber lip is fabricated partially of polyethylene, has the
advantage, on the other hand, that by using polyethylene as a
material for the wiper blade rubber lip, low dry friction
coefficients .mu..sub.tr can be achieved.
[0006] Under certain operating conditions, this leads to a lower
development of noise as compared with the state of the art and
namely even with a dry windshield.
[0007] Because of the dry friction coefficients of the wiper blade
in accordance in the invention that are low as compared to the
state of the art, wiper drives of smaller dimensions with
corresponding reduced power can be used advantageously.
[0008] The wiper blade rubber lip can either be coated with
polyethylene and/or contain polyethylene in volume.
[0009] According to a preferred embodiment, the polyethylene is
PE-UHMW. PE-UHMW, i.e., polyethylene with an ultrahigh molecular
weight, is especially suited to coat wiper blade rubber lips since
it already has a low dry friction coefficient as a whole material.
Thus, for example, a whole material specimen of PE-UHMW with a
contact length of 8 mm and a load of 0.128 N on a rotating glass
shaft, which is moving at 0.1 m/s, has a dry friction coefficient
of .mu..sub.tr 0.21.
[0010] In the case of vulcanization of a rubber material, which is
coated with PE-UHMW, the PE-UHMW combines adhesively with the
rubber material through diffusion. If the PE-UHMW is applied to the
rubber material as a powder, it sinters during vulcanization.
PE-UHMW in particular adheres on a rubber material in such a way
that the polyethylene/rubber material bond tears starting at a
certain load in the bond.
[0011] Alternatively, the polyethylene of the wiper blade in
accordance with the invention can be PE-HD, i.e., high-density
polyethylene, or even PE-X, i.e., interlaced polyethylene. PE-X in
particular is applied in molten form to a rubber material during
the manufacture of the wiper blade in accordance with the invention
and thermally secondarily cross-linked during vulcanization.
[0012] The invention also deals with a process to manufacture a
wiper blade for a windshield wiper, which is comprised of a wiper
blade rubber with a wiper blade rubber lip. With this process, the
wiper blade rubber lip is manufactured by vulcanizing a rubber
material together with polyethylene.
[0013] The rubber material can be manufactured on the basis of
natural rubber. Using synthetic rubber materials as the base
material for the wiper blade rubber lip is also conceivable,
however.
[0014] In a preferred embodiment of the process in accordance with
the invention, the vulcanization takes place under the conditions
that are customary for vulcanizing a rubber.
[0015] It is preferred that the polyethylene be present in powder
form as a primary material and, namely, with a grain size of
approx. 0.1 .mu.m to 30 .mu.m.
[0016] In a preferred embodiment of the process according to the
invention, the rubber material is coated with polyethylene before
vulcanization. The vulcanization of the molded part coated with
polyethylene can then take place in a mold. The vulcanized work
piece made of the rubber material and the polyethylene can be
demolded easily.
[0017] The coating of the rubber material with polyethylene that
takes place before the joint vulcanization can occur in such a way
that the rubber material put into the mold can be coated with a
dispersion containing polyethylene particles, or that the rubber
material can be dusted with polyethylene powder. A customary
electrostatic powder coating process is particularly suited for
applying a polyethylene powder. The unvulcanized rubber material is
advantageously dusted all-over with PE powder. A partial is
covering is possible, however.
[0018] However, the polyethylene can also be applied by means of a
fluidized bed. In an advantageous embodiment, the rubber material
in this case becomes hot and is extruded from an extrusion head in
a tacky manner. The rubber material then makes its way through an
opening into the lowly concentrated fluidized bed of very fine
PE-UHMW powder with a grain size between 0.1 .mu.m and 15 .mu.m,
and then leaves the fluidized bed through an opening, in order to
then be blown on by clean purging air. As a result, the
polyethylene particles that do not adhere to the rubber material
are removed. The purging air also can in turn be used to operate
the fluidized bed.
[0019] With another embodiment of the process according to the
invention, unvulcanized rubber material is pressed into a mold in a
hot press with a special steel tool, for example, at a temperature
of 180.degree. C. and a pressure of 70 bar for a duration of 10
seconds, then removed and cooled down with water. After drying, the
partially vulcanized rubber molded part that was fabricated in this
way is thinly dusted on both sides with PE-UHMW powder. Finally,
the dusted molded part is vulcanized at a pressure of 70 bar, a
temperature of 180.degree. C. for a duration of 5 minutes in a mold
corresponding to the rubber molded part.
[0020] However, the rubber material and the polyethylene can also
be combined with one another in accordance with a co-extrusion
process. In the case of co-extrusion, a polyethylene melt,
polyethylene film, polyethylene monofilament or polyethylene cord
is fed in this process at least in the area of the wiper blade
rubber lip of the wiper blade rubber. Finally, the rubber material
and the polyethylene adjacent to it are jointly vulcanized.
[0021] However, it is also possible to manufacture the wiper blade
rubber with the wiper blade rubber lip in accordance with an
injection molding process. In this case, a film, a monofilament or
a cord of polyethylene is put into an injection mold before
injection molding, or else the injection mold is coated with a
dispersion or a powder of polyethylene.
[0022] If the polyethylene is supposed to be contained in volume in
the wiper blade rubber lip, the wiper blade rubber lip is
expediently manufactured of a mixture, which is comprised of the
rubber material and the polyethylene.
[0023] According to an advantageous embodiment, the mixture
contains between 1% and 50% polyethylene powder, in particular
PE-UHMW powder.
[0024] Additional advantages and advantageous further developments
of the subject of the invention are yielded from the description,
the drawings and the patent claims.
DRAWINGS
[0025] Four exemplary embodiments of the wiper blade in accordance
with the invention of a windshield wiper device of a motor vehicle
are shown schematically simplified in the drawings and are
explained in greater detail in the following description. The
drawings show:
[0026] FIG. 1 A depiction of the principle of a wiper blade in
cross-section.
[0027] FIG. 2 A cross-sectional depiction of a second embodiment of
a wiper blade.
[0028] FIG. 3 A third embodiment of a wiper blade in
cross-section.
[0029] FIG. 4 A fourth embodiment of a wiper blade.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0030] FIG. 1 depicts a wiper blade, which is composed of a wiper
lip 2 featuring a wiper edge 5 made of rubber material, a head
piece 3 made of rubber material (shown only partially in this case)
and a so-called reversing bridge 4 made of rubber material, which
is arranged between the head piece 3 and the wiper lip 2.
[0031] The wiper lip 2, the head piece 3 and the reversing bridge 4
are provided with a surface formed by a polyethylene layer 1, which
for the sake of clarity is shown in FIG. 1 enlarged as compared to
the wiper lip 2, the head piece 3 and the reversing bridge 4. The
polyethylene layer 1 is composed primarily of PE-UHMW, i.e., of
polyethylene with an ultrahigh molecular weight.
[0032] The wiper blade in accordance with FIG. 1 is manufactured in
such a way that first partially vulcanized rubber material is
pressed into a wiper blade mold in an extruder by means of a tool,
then dusted with PE-UHMW powder and finally vulcanized. The
conditions for vulcanization correspond to customary vulcanization
conditions.
[0033] The resulting material quality of the wiper blade rubber lip
is such that in the case of a measurement where the wiper blade 1
is adjacent to a rotating glass plate and the wiping speeds as well
as the pressure conditions are like with a motor vehicle, dry
friction coefficients .mu..sub.tr between 0.32 and 0.48 can be
achieved.
[0034] The exemplary embodiment of a wiper blade depicted in FIG. 2
is comprised essentially of the same components as the wiper blade
according to FIG. 1. However, the wiper blade according to FIG. 2
differs from the one according to FIG. 1 because of a so-called
wiper edge 5, which is free of polyethylene.
[0035] The exemplary embodiment of the wiper blade depicted in FIG.
3 is also comprised essentially of the same components as the
exemplary embodiment according to FIG. 1, but it differs from the
latter, however, in that the wiper edge 5 embodied on the wiper lip
2, the reversing bridge 4 and the heard piece 3 are free of
polyethylene and the wiper lip 2 is coated with polyethylene only
on its lateral areas adjacent to the wiper edge 5, i.e., it is only
partially coated with polyethylene.
[0036] The exemplary embodiment shown in FIG. 4 shows a wiper
blade, which essentially is comprised of only a partially depicted
head piece 3 made of rubber material, a reversing bridge 4 made of
rubber material that attaches to the head piece 3 and a wiper lip 6
with a wiper edge 5. The wiper lip 6 is composed of a rubber
material in which polyethylene in the form of PE-UHMW is embedded.
The wiper lip 6 is manufactured of a primary material, which
contains approx. 40% polyethylene.
[0037] The wiper blade rubber at hand is an extrusion part.
Alternatively, the wiper blade rubber can be manufactured in a
known manner also in accordance with an extrusion process or by
compression molding.
* * * * *