Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to a motor vehicle wheel.
A vehicle wheel of the type to which the present
invention pertains can often be found on French passenger cars.
The spoke disk on such wheels is stamped out of sheet steel and in
its center a nut is fastened, the nut having a tapped hole aligned
co-axially to the axis of rotation of the wheel. The tapped hole
on such known wheels has a diameter of about lOmm. Screwable
thereinto is a fastening part for the hub cap, with a hexagonal
head of a size corresponding to that of the fastening nuts for
fastening the wheel. Thus, the fastening part can be opened at
any time by means of the standard wrench and the hub cap can be
removed. Thus, the hub cap is not specially protected against
theft. Another disadvantage of this well known design is that
only the outer edge of the hub cap is pressed against the spoke
disk. If oil or grease leaks at the grease cap of the wheel axle
- a fact which cannot be avoided entirely - it can penetrate
through the tapped hole to the outside of the spoke disk, to be
thrown by centrifugal force against the wheel fastening nuts to
dirty them and, through an edge gap between the hub cap and the
spoke disk toward the outside. This latter area, located toward
the perimeter of the spoke disk, can never be kept completely
tight, so that traces of oil which leak outward can, when mixed
with dirt, cause marks which are very difficult to remove. In the
reverse direction, however, the penetration of dirty water from
the outside toward the grease cap can not be prevented either, so
that here, so-to-speak, there is a circulation system in which a
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mixture of dirt, water and oil will be thrown from the hub zone
radially outward.
Moreover, the well-known spoke disks of steel are very
limited reyarding optically attractive design.
Therefore, one increasingly goes over to producing spoke
disks of light metal which are cast, for instance, of an aluminum
alloy. Regarding the design, one has here a relatively free hand
so that antique spokes can be imitated. With these designs, the
hub cap has been as a continuous one-piece part which is to be
clipped to the spoke disk by means of a lock-in connection. Here,
the securement is not reliable and especially for these optically
very attractive hub caps unauthorized removal is made altogether
too easy.
It is therefore the object of the present invention to
provide a motor vehicle wheel in which the advantages of
production from light metal can be utilized and in which the hub
cap - especially the cover plate - is fixed securely on the spoke
disk and cannot be removed easily by unauthorized persons.
Furthermore, the fastening screws which are covered by the hub
cap, should remain as clean as possible and oil should be
prevented from migrating from the hub zone to the outside of the
spoke disk. The spoke disk and the hub cap or the cover plate and
the screw part are preferably to be designed in an optically
attractive manner.
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Secure fastening of the hub cap to the spoke disk is
especially important if a ventilator is put on as a hub cap,
extending disk-like over almost the entire inner surface of the
wheel up to the level of the rims, and carrying on its inside
radial ribs through which a forced air stream for the cooling of
the brakes is brought about. Such ventilators have considerable
mass, and for reasons of safety they must be reliably anchored on
the spoke disk.
In one broad aspect the present invention relates to a
motor vehicle wheel having a spoke disk and a hub cap with the
following characteristics: a) the spoke disk is approximately
plate-shaped, and in its center there is a central bore which is
aligned coaxially to the axis of rotation of the wheel; b) around
the axis of rotation, passage holes for the passage of screw bolts
are provided for fastening the spoke disk on the axle of a motor
vehicle, with the inside of the spoke disk in the mounted state
pointing toward the axle of the motor vehicle; c) the hub cap
consists of a cover plate having a center bore, and a fastening
part which includes a shaft and a head, the fastening part being
adapted to pass through the center bore of the cover plate to be
fixed by means of its shaft in the bore of the spoke disk and the
head having a bearing surface pointing toward the bore of the
plate, for bearing against the cover plate in order to hold it
firmly on the spoke disk; characterized in that the spoke disk is
made of light metal; the central bore of the spoke disk is adapted
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to engage the shaft of said fastening part of said hub cap and has
a diameter which is larger than 5 cm; and the cover plate is
provided with an annular surface, which upon engagement of said
shaft in said central bore of the spoke disk, is pressed against a
countersurface formed in the spoke disk.
In a preferred embodiment, the central bore of the spoke
disk is a tapped hole, and the shaft of the fastening part is a
complementary screw.
The tapped hole provided in the wheel of the present
invention is relatively big, so it can be made directly in the
light metal of the wheel and no separate metal insert is required
for it. Therefore, an altogether more simple production of the
spoke disk is possible. The large diameter of the tapped hole
also opens up the possibility of pressing the cover plate against
the spoke disk directly in the area surrounding the tapped hole,
because in this area, a large contact surface is provided.
Moreover, tensional force is transferred from the screw part
without considerable radial shifting so that the contact pressure
between the head, the cover plate and the spoke disk can be great.
This also promotes the safe fixing of the cover plate on the disk,
and brings about the sealing of the hub area. Furthermore, the
head of the screw part can be sufficiently large and thereby be
designed in a visually very attractive manner. A standard tool
cannot be used on this large head and unauthorized removal of the
hub cap will therefore be impeded.
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In further aspects of the present invention, especially
effective sealing between the screw part, the cover plate and the
spoke disk is achieved. Simultaneously, the friction-tightness is
increased here with utilization of the wedge principle whereby the
reliability of the connection is also improved.
In a further aspect, a collecting space for dirt, which
possibly might penetrate from the outside, is formed by an annular
groove in the cover plate.
In a further embodiment, an effective pairing of the
materials out of which the wheel is made prevents contact
corrosion. Also, the present invention is producible in a simple
manner with respect to production technique.
In a further aspect of the present invention, there is
facilitated, on the one hand, the mounting and demounting of the
screw element by means of a special wrench and, on the other hand,
this form corresponds to an esthetic demand of our time.
In another aspect it is assured that the cover disk is
always aligned in a predetermined rotary position relative to the
spoke disk so that the pattern present in the spoke disk can be
continued on the outside of the cover plate.
In the following, the invention is explained in detail by
means of especially preferred embodiments illustrated in drawings;
Figure 1 shows at a reduced scale a cross-section through
a spoke disk according to the invention, with a hub cap put on;
Figure 2 shows a partial view in the direction of the
arrow 2 according to Figure l;
Figure 3 shows a partial Pone of Figure 1, enlarged; and
Figure 4 shows an illustration corresponding to Figure 3
according to a variation of the invention.
The spoke disk 11 according to Figure 1 and 3 is
approximately plate~shaped. On its outer edge 12 a multitude of
holes 13 are provided to connect the spoke disk 11 to the wheel
rim (not illustrated). The spoke disk 11 has in its outer
peripheral zone a multitude of interruptions 14 which give it a
spoke-like appearance. In its center there is a center hole or
bore 16 which is aligned coaxial to the axis of rotation 17 of the
spoke disk 11. This center bore serves in a well-known manner to
accommodate, for instance, a grease cap on the axle of a motor
vehicle. A circle of passage holes is provided around the axis of
rotation 17 (only the passage hole 18 is illustrated). The screw
bolts which fasten the spoke disk onto the axle of a motor vehicle
pass through these holes 18 - side 19 of the spoke disk 11
pointing, in the mounted state, toward the axle of the motor
vehicle. On the opposite side of the passage hole, fastening nuts
may be screwed on in a well-known manner.
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In its central area, the spoke disk 11 is provided with a
sleevelike extension 21 which follows the center hole or bore 16
axially outwardly. Extension 21 has a tapped hole 22 and,
following that, a cylindrical recess 23. In a preferred
embodiment, center bore 16 has, at its narrowest point, a diameter
of about 71mm and it extends in the axial direction over a length
of about 26mm. In such an embodiment, the tapped hole 22 has a
diameter of about 70mm and extends in the axial direction over a
length of about 10mm. Recess 23 is shaped like a step, the
innermost surface thereof being countersurface 24. The
countersurface 24 ranges from an inside diameter of about 72.5mm
to an outside diameter of about 77mm. The cylindrical recess 23
extends in the axial direction over a length of about 3mm.
A hub cap 26, is provided to cover the central area,
radially outwardly at least as far as fastening screws which pass
through holes 18. The hub cap 26 consists of a cover plate 27 and
a screw part 28. The cover plate 27 has a cylindrical extension
29, with an axially inner face forming an annular surface 31 which
bears on the countersurface 24. The extension 29 has (in the
embodiment being described), an outside diameter of 77 and thereby
fits accurately into the recess 23. On its outer surface, axially
opposite the annular surface 31, the cover plate 27 is provided
with a bevel seat 32 which ranges from an inside diameter of about
72.5mm to an outside diameter of about 80mm with an angle of taper
of about 45. The bevel seat 32 is followed radially outward by a
transition surface 33, followed by an annular groove 34 directly
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inwardly. This is followed radially outwardly by a counterplane
surface 36. The counterplane surface 36 is shifted, relative to
the transition surface, outwardly by about lmm in the axial
direction.
The screw part 28 is made in two parts with an inner part
37 and a cap 39. The inner part 37 is made of plastic and is
provided with a shaft with an outer thread 38 which corresponds to
the tapped hole 22. The remainder of inner part 37 is the head of
the screw part 28, on which is mounted cap 39. The cap 39 and
inner part 37 are connected in a formlocking manner with each
other and also are glued in an overlapping zone 41.
On the head of screw part 28, adjacent the outer thread
37, there is a bearing surface which is designed as a cone-shaped
shell 42. It corresponds to the bevel seat 32 and, in a preferred
embodiment, ranges from an inside diameter of about 68mm to an
outside diameter of about 82mm. The cone-shaped shell 42, at its
outer periphery, is followed by a radial flange 43, the outer edge
of the inner surface of which forms an annular plane surface 44
which bears on the counterplane surface 36. Because of the
annular groove 34 and the course of the cross-section of the cover
plate 27 curved thereby in this zone, the counterplane surface 36
can be somewhat elastic relative to the bevel seat 32. A sealing
effect between the plane surface 44 and the counterplane surface
36 is thereby assured.
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During the screwing of the screw part 28 into the tapped
hole 22 by means of the outer thread 38, the cone-shaped shell 42
presses wedgelike against the bevel seat 32 whereby the cover
plate 27 made of plastic is somewhat widened in the zone of its
cylindrical extension 29. The outer periphery of the cylindrical
extension 29 is thereby pressed against the inside wall of the
recess 23 and the annular surface 31 is simultaneously pressed
against the countersurface 24. This results in excellent sealing
and the cover plate 27 is fixed on the spoke disk 11 with high
frictional engagement. Moreover, the sealing effect and the
fixing of the coverplate in position is increased by a wedge
effect between the cone-shaped shell surface 42 and the bevel seat
32. It will also be noted that the tension force of the screw
part 28 is transferred without radial shifting since contact
between the cone-shaped shell 42 and the bevel seat 32 is made at
about the same radial distance as the contact between the annular
surface 31 and the countersurface 24. Also, because of the large
diameter of the tapped hole 22, the thread engagement is
sufficiently loadable and is able to absorb very great tensional
forces. The sealing in the zone between the plane surface 44 and
the counterplane surface 36 acts as an additional sealing and
prevent the penetration of dirt to the principle sealing surface
in the zone of the cone-shaped shell 42. Thereby the danger that
the principle sealing surface will be damaged by penetrating dirt
that causes grooves during tightening is reduced.
In the preferred embodiment, the cap 39 oE the screw part
28 is made of an aluminum alloy and is many-sided on its outside.
Thus, the screw part 28 can be mounted and demounted by a special
wrench having a wrench opening of about 82mm. It is important
that such a special wrench is not easily on hand, so that removal
of the hub cap by unauthorized persons is made quite difficult.
Referring to partial view of Figure 2, the cover plate 27
in a preferred embodiment, conforms to and continues the spoke
pattern of the spoke disk 11. In order that the pattern is always
put into the conforming position, there is (as shown in Figure
1), anchored on the cover plate 27 a pin 46. Pin 46 protrudes
about parallel to the axis of rotation 17 and is shifted radially
relative to it. Pin 42 fits into a bore 47 in the spoke disk 11,
which bore 47 is located so that when pin 42 is inserted therein
the spoke pattern on the disk is aligned with the spoke pattern of
the cover plate 27. The spoke disk 11 can be made of an aluminum
alloy, likewise the cap 39. The cover disk 27 and the part 37 are
expediently made of plastic which because of its capacity to be
shaped is favourable with respect to production technique.
Moreover, the use of plastic avoids also the danger of contact
corrosion at the contact spots.
The outer edge of the cover plate 27 does not touch the
spoke disk 11, so that water possibly present in the hollow space
located in between the cover plate 27 and the spoke disk 11
(perspiration water) can get out. Because of the good sealing in
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the hub zone, however, oils will not escape here to soil the spoke
disk 11 or tire.
The cover plate 27 according to the described embodiment
is provided, first of all, as an optical occlusion. As an
alternative to it, however, it can be made also to function as a
ventilator. The design of a ventilator is known and needs no
detailed explanation here. However, it is important, if the cover
plate 27 is to be used as a ventilator, that the center zone is
made in the form explained above by means of Figure 1. This will
assure a firm and reliable hold on the spoke disk 11 by the
ventilator, and will also produce the necessary sealing of the hub
zone.
The illustration in Figure 4 corresponds greatly to the
cut-out shown in Figure 3. However, the area of contact between
the cover plate and the spoke disk is somewhat modified. For ease
of comparison, the reference numbers used in Figure 4 are simply
increased by the factor 10. Following the tapped hole 220 of the
spoke disk 110, a countersurface 240 defines a bevel seat on the
axially outermost surface of the sleeve-like extension 210. A
corresponding annular surface 310 formed in the cover plate 270
fits it firmly. In comparison to Figure 3, some sharp-edged
transitions are thus avoided. Figure 4 also shows a spring ring
281, which is held in a groove 282 before the outer thread 380 of
the screw part 280. By this arrangement the screw part 280 and
the cover plate 270 are connected with each other so that they
cannot become separated easily, and misplaced.
Not illustrated in the drawings, is a variation according
to which the head of the screw part 28 which is many-sided on its
outside (and may be many sided in area 41, where the cap 39 fits
on the inner part 37) is not provided exclusively with planar
surfaces. Rather several curved surfaces may be used. For
example, the many-sided head of the screw part 28 can be formed as
an epicycloid or hypocycloid. If this is done, then unauthorized
removal of the hub cap will be impeded to a very great extent, as
a custom built, and not merely a non-standard size wrench must be
used to remove a head with curved sides.
In place of the pin 46 / hole 47 shift guard drawn in
Figure 1, a radially protruding stop cam can be firmly formed onto
the extension 21 against which a countercam of the cover plate can
be put. Especially if the cover plate is designed as a
ventilator, it is recommended to design the countercam in such a
way that it reaches over the stop cam in order to prevent turning
in either direction.
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