Note: Descriptions are shown in the official language in which they were submitted.
1 337234
TITLE OF THE INVENTION
Casting device, method for using the device, casting device of vehicle
wheel, method for using the device, and vehicle wheel.
BACKGROUND OF THE ~NVENTION
[Field of the Invention]
This invention relates to a casting device, a method for using the device,
a casting device of a vehicle wheel, a method for using the device, and a vehicle
wheel.
[Brief Description of the Prior Art]
In a conventional casting device, when a casting is going to be
manufactured, a mold temperature is set sufficiently high in order to obtain a
favorable run of a hot melt.
This conventional casting device, however, has such disadvantages as that
as the mold temperature is set sufficiently high, it takes a long time for the hot
melt to be hardened, and as a result, the casting structure of the casting does not
become dense, and therefore, a high strength is difficult to obtain.
Also, in a conventional low pressure casting device of a vehicle wheel, a
main body of a mold is provided at its lower part with a weir and a hot melt is
poured into a casting space through this weir (Japanese Patent Early Laid-open
Publication No. Sho 55-120466).
- 1 337234
However, this conventional casting device has such
disadvantages as that as the cooling device is disposed at a
lower part of the main body of the mold, it is difficult to
maintain the hot melt in a constant level of temperature, and
as a result, a casting defect tends to occur.
Also, notwithstanding that a high strength is re-
quired for a disk portion of a vehicle wheel, as the weir is
disposed as the lower part of the main body of the mold in the
conventional casting device, it is difficult to cool the disk
portion, and as a result, the disk portion is difficult to be
improved in strength.
The present invention has been accomplished in order
to overcome the above-mentioned disadvantages of the prior
art.
SUMMARY OF THE INVENTION
It is therefore a first object of the present
invention to provide a low pressure dye casting device of a
vehicle wheel in which no casting defect can be found, a cast-
ing structure is fine, and a disk portion is improved in
strength.
The first object of the present invention can be
achieved by a low pressure dye casting device of a vehicle
wheel characterized in that a main body of a mold having a
space section for forming a rim is provided at one side there-
of with a weir which is opened up in said space section for
forming a rim, and said main body of a mold is provided at a
portion for forming a disk thereof with a partially and
, --
` ~ 1 337234
separately forceful cooling means.
The first obiect of the present invention can be
achieved by a low pressure dye casting device of a vehicle
wheel characterized in that a main body of a mold having a
space section for forming a rim is provided at one side there-
of with a weir which is opened up in a connecting portion
between said rim forming space section and a spoke portion
forming space section.
The first object of the present invention can be
achieved by a low pressure dye casting device of a vehicle
wheel characterized in that main main body of a mold having a
space section for forming a rim is provided at one side there-
of with a plurality of dams which are opened up in said rim
forming space section.
The first object of the present invention can be
achieved by a low pressure dye casting device of a vehicle
wheel characterized in that a main body is provided with
primary cooling means generally uniformly arranged thereon,
a disk forming portion in said main body comprising
a nest, said nest being provided with auxiliary cooling means
separately from said primary cooling means.
The first object of the present invention can be
achieved by a low pressure dye casting device of a vehicle
wheel wherein auxiliary cooling means is disposed under a
prescribed portion of a bolt hole of the vehicle wheel which
is to be cast.
1 337234
The second object of the present invention can be
achieved by providing a vehicle wheel, in which a clear safety
of the wheel as an important part is shown by index.
The second object of the present invention can be
achieved by an aluminum alloy vehicle wheel producted by a low
pressure dye casting device of a vehicle wheel with a DAS
(Dendrite Arm Spacing) measuring value of a tip portion of a
rim (hereinafter referred to as the "tip portion of the rim at
the opposite disk side") which is the most remote from a disk
portion of the wheel being smaller than a measuring value of a
rim body portion,
a DAS measuring value of a rim carrying portion of
said disk portion is smaller than a DAS measuring value of a
central portion of said disk,
said DAS measuring value of said rim carrying
portion of said disk portion being equal to or smaller than
said DAS measuring value of said rim body portion.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a partial sectional view of a casting
device according to the invention;
Fig. 2 is an enlarged sectional view of a portion
indicated by II of Fig. 1;
Fig. 3 is a sectional view taken on line III-III of
Fig. 2;
Fig. 4 is a sectional view of a casting device;
Fig. 5 is an enlarged sectional view of a portion
indicated by V of Fig. 4;
`- 1 337234
Fig. 6 is a bottom view of a disc-shaped molding
member of Fig. 5;
Fig. 7 is a bottom view of an annular molding member
of Fig. 5;
Fig. 8 is a sectional view of the mold of Fig. 7;
Fig. 9 is a perspective view of a casting cast by
the mold of Fig. 8;
Fig. 10 is a sectional view of one embodiment;
Fig. 11 is a sectional view of another embodiment;
Fig. 12 is a sectional view of another embodiment;
Fig. 13 is a sectional view of another embodiment;
Fig. 14 is a sectional view of another embodiment;
Fig. 15 is a sectional view of another embodiment;
Fig. 16 is a sectional view of another embodiment;
Fig. 17 is a partial sectional view of a portion
indicated by an arrow of Fig. 16;
Fig. 18 is an enlarged view of a portion indicated
by XVIII of Fig. 16;
Fig. 19 is a sectional view taken on line XIX-XIX of
Fig. 17;
Fig. 20 is a sectional view taken on line XX-XX of
Fig. 17.
Fig. 21 is a schematic view showing a secondary
branch (secondary arm) growing at each side of a main shaft of
a dendrite in an aluminum alloy;
Fig. 22 is an explanatory view showing a distance
between a plurality of secondary arms and how to count the
1 337234
number of secondary arms measured within said distance; and
Fig. 23 is a partly omitted sectional view obtained
by cutting a vehicle wheel along a plane including a rotation-
al shaft of a wheel and showing a position for taking a sample
(the rem~' n; ng half part symmetrical with respect to the
rotational shaft is omitted).
DETAILED DESCRIPTION OF THE EMBODIMENTS
One preferred embodiment of a casting device of a
vehicle wheel according to the present invention will be
described with reference to Figs. 1 through 5.
In Fig. 1, M denotes a mold for molding a vehicle
wheel. The mold 1 comprises a combination of a lower mold 1,
a horizontal mold 2 and an upper mold 3. This mold M has a
casting space 4 of a vehicle wheel shape. 11 denotes a first
nest of the lower mold 1 and is secured to a central portion
of the lower mold 1 by a bolt 12. This first nest 11 shapes
an outer surface of a hub portion (of the vehicle wheel).
Also, 111 denotes a second nest of the lower mold 1 and is
secured to the outer surface of the first nest 11 also by the
bolt 12. This nest 111 shapes an axle hole of the vehicle
wheel. Also, 31 denotes a nest of the upper mold 3 and is
engaged with a central portion of the upper mold 3. This nest
31 shapes a rear surface of the hub portion (of the vehicle
wheel). 41, 41,... denote a feeding head space, 42 denotes a
hot melt passage commllnlcated with the casting space 4 and 43
denotes a weir formed at the hot melt passage 42.
- 1 337234
Next, the nest 31 portion in the upper mold 3 will
be described in detail with reference to Figs. 2 and 3.
The nest (of the upper mold 3) 31 is opened up at
its upper end, with which a vent barrel 5 is engaged. 6
denotes an extruding pin which is reciprocally movably insert-
ed through the central portion of the vent barrel 5. Also, S1
denotes a partition wall which is integral with an inter-
mediate portion of the vent barrel 5. The underneath of the
partition wall 51 within the vent barrel 5 forms a vent room
which is referred to in the claims as the "auxiliary space".
54 denotes a contact surface between the vent barrel 5 and the
nest (of the upper mold 3) 31 and corresponds to the communi-
cating passage of this invention. Through this contact sur-
face 54, the casting space 4 and the auxiliary space 7 are
communicated with atmosphere. 511, 511,... vent holes formed
in the partition wall 51. Next, 52 denotes a lid member which
covers the opening at the upper end of the vent barrel 5. The
lid member 52 is formed with a pressurized air inlet hole 53.
8 denotes a connecting piece engaged with the inlet hole 53.
81 denotes a gas pipe connected with the connecting piece 8.
By virtue of the foregoing arrangement, when a shutter valve
82 of the gas pipe 81 is opened, the pressurized air can enter
into the vent barrel 5 and thus into the auxiliary space 7
through the connecting pipe 8.
A method for using such constructed casting mold M
will be described next.
First, in the state where the pressurized gas feed-
1 337234
-
ing valve 82 is closed and a discharging valve 83 is opened, a
hot melt is poured into the casting space 4. At this time,
air within the casting space 4 is discharged through the dis-
charge valve 83. And, when the hot melt reached a lower end
portion of the vent room 7 (see the imaginary line of Fig.
2), the discharging valve 83 is closed and the pressurized gas
feeding valve 82 is opened to feed the pressurized gas into
the vent room (auxiliary space) 7 to raise the internal
pressure of the vent room (auxiliary space) 7. Then, the sur-
face of the hot melt now reaching the lower end portion of the
vent room (auxiliary space) 7 is pressurized. As a result,
the hot melt enters into every corner of the casting space 4
simply and easily. The hot melt A moves upward within the
casting space 4. At this time, air within the casting space 4
is discharged into atmosphere through the contact surface 54.
And, when the hot melts reach the border line between the
casting space 4 and the vent room (auxiliary space) 7, a gap
of the contact surface 54 is blocked with the hot melt A.
Therefore, air within the vent room (auxiliary space) 7
becomes unable to be discharged. As a result, the temperature
of the hot melt is no more raised. Therefore, the interior of
the vent room (auxiliary space) 7 is secured as a pressurized
space.
And, the shutter valve 82 of the gas pipe 81 is
opened to feed the pressurized air into the vent room
(auxiliary space) 7 to raise the internal pressure of the vent
room (auxiliary space) 7. Then, the surface of the hot melt A
- 1 337234
now reaching the lower end portion of the vent room (auxiliary
space) 7 is pressurized. As a result, the hot melt A enters
into every corner of the vent room (auxiliary space) 7 simply
and easily.
As the casting device is constructed as mentioned
above, gas within the casting space can be discharged and a
pressurized fluid can be fed in the direction of the casting
space through the vent hole.
Accordingly, in the case that this casting device is
used, a favorable run of a hot melt can be maintained without
raising the temperature of the mold. Therefore, there can be
obtained a casting of a high density of casting structure,
i.e., a casting of high strength.
As the method for using the casting device is
carried out as mentioned above, the surface of the hot melt
within the casting space can be pressurized through the vent
hole after the hot melt is poured. Accordingly, a favorable
run of a hot melt can be enhanced.
Therefore, in the case that the method or using the
casting device is carried out, a favorable run of a hot melt
can be maintained without raising the temperature of the mold.
Therefore, there can be obtained a casting of a high density
of casting structure, i.e., a casting of high strength.
As the casting device of a vehicle wheel is con-
structed as mentioned above, gas within the disk forming cast-
ing space can be discharged and a pressurized fluid can be fed
in the direction of the disk forming casting space through the
1 ~37234
vent hole.
Accordingly, in the case that this casting device is
used, a favorable run of a hot melt can be maintained without
raising the temperature of the mold. Therefore, there can be
obtained a vehicle wheel of a high density of casting
structure, i.e., a vehicle wheel of high strength.
As the method for using the casting device of a
vehicle wheel is carried out as mentioned above, the surface
of the hot melt within the disk forming casting space can be
pressurized through the vent hole after the hot melt is pour-
ed. Accordingly, a favorable run of a hot melt can be enhanc-
ed.
Therefore, in the case that the method for using the
casting device of a vehicle wheel is carried out, a favorable
run of a hot melt can be maintained without raising the temp-
erature of the mold. Therefore, there can be obtained a
vehicle wheel of a high density of casting structure, i.e., a
vehicle wheel of high strength.
As the casting device is so constructed as mentioned
above, that is, as a communicating passage is disposed on the
border line between the casting space and the auxiliary space
in a mold and the auxiliary space is communicated with
atmosphere through this communicating passage, when a hot melt
is poured into the casting space, the hot melt moves upward
along the wall surface of the casting space, however, when the
hot melt reaches the border line between the casting space and
the auxiliary space, air within the auxiliary space becomes
-10-
1 337234
unable to be discharged, and therefore, the hot melt is not
moved upward any further, and thus, the auxiliary space can be
secured as a pressurized space.
Accordingly, in the case that this casting device is
used, a favorable run of a hot melt can be maintained without
raising the temperature of the mold. Therefore, there can be
obtained a casting of a high density of casting structure,
i.e., a casting of high strength.
Next, one embodiment will be described with
reference to Figs. 4 through 7.
In Fig. 4, M denotes a casting device. The casting
device M comprises a combination of a lower mold 1, an inter-
mediate mold (first nest) 11, a horizontal mold 2, an upper
mold 3, and an upper auxiliary mold 333. 4 denotes a cavity
(casting space) of the casting device 1 and the cavity 4 has a
shape like a vehicle wheel. 111 denotes a nest projecting
from the intermediate mold 11 and extending inside the cavity
4. This nest 111 is adapted to form a shaft hole of the
vehicle wheel. Next, 42 denotes a hot melt passage also
extending sideward in the horizontal mold 2. This hot melt
passage 42 is opened up at a side portion (rim forming space
portion) of the cavity 4 through a weir 42. The other end of
this hot melt passage 42 is opened up at an outer surface of
the horizontal mold 2. 7 denotes an auxiliary mold which is
intimately contacted with the outer side of the horizontal
mold 2. 71 denotes a dome-shaped primary space which is form-
ed inside the auxiliary mold 7 and opened up at a lower sur-
-11-
1 337234
face of the auxiliary mold 7. Similarly, 72 denotes a con-
necting passage which is formed in the auxiliary space 7 as in
the case with the primary space 71. One end of this connect-
ing passage 72 is opened up in the primary space 71, and the
other end is opened up 721 at the left-hand side (in Fig. 4)
of the auxiliary mold 7. And, the outer side opening 721 is
opposite the outer side opening 222 of the hot melt passage
42. Accordingly, a hot melt within the primary space 71 pass-
es through the connecting passage 72, and then can be flowed
into the hot melt passage 42. 731 denotes a stroke auxiliary
ring which is abutted against a peripheral edge portion of the
lower side opening 711. Likewise, 732 denotes a stroke main
body which is annexed to a lower side of the stroke auxiliary
ring 731. The stroke main body 732 and the stroke auxiliary
ring 731 integrally form the so-called "stroke". 74 denotes a
flat plate-shaped filter which is held between the auxiliary
mold 7 and the stroke auxiliary ring 731. This filter 74
shows a net-like configuration and is adapted to filtrate a
hot melt which is to be fed to the auxiliary mold 7 as a hot
melt changing device.
Next, in Fig. 5, 314 denotes an inserting hole which
is formed in an upper surface of a central portion in the
upper mold 3. This inserting hole 314 is communicated with
the cavity 4. 81, 82 and 83 denote annular molding members
which are inserted into the inserting hole 314 through a space
S and are then gradually stacked up one upon the other. In
this embodiment, the inner diameter of the middle stage
-12-
1 337234
annular molding member 82 is larger than the inner diameter of
the lower stage annular molding member 81. Similarly, the
inner diameter of the upper stage annular molding member 83 is
larger than the inner diameter of the middle stage annular
molding member 82. The inner peripheral surface of the
annular molding members 81, 82 and 83 are tapered and dilated
toward the lower end thereof. And, connecting portions on the
inner surface of each of the annular molding members 81, 82
and 83 shows a step-like configuration. This arrangement is
made in order to prevent an occurrence of an undercut even
when the annular molding members 81, 82 and 83 are moved by
the space S in the horizontal direction within the inserting
hole 314. 84 denotes a disc-shaped molding member which is
inserted into the inserting hole 314 through the space S in
the same manner as the annular molding member 81, 82 and 83.
This disc-shaped molding member 84 is placed on the upper sur-
face of the annular molding member 83 and forms a feeding head
forming space A at an inner peripheral portion of the annular
members 81, 82 and 83. A connecting portion between the disc-
shaped molding member 84 and the annular molding member 83 is
also formed with a step portion in order not to generate an
undercut as mentioned. Also, in the disc-shaped molding
member 84, 841, 841,...denote degasing holes, and B, B,...
denote vents (see Fig. 6). 842, 831, 821 and 811 denote
degasing grooves which are formed at the lower surfaces of the
annular molding members 81, 82 and 83 (see Figs. 6 and 7.
Fig. 6 shows an annular molding member 85). These grooves
1 337234
842, 931, 821 and 811, when stacked up, function as a degasing
portion (see Fig. 5).
As the casting device is so constructed as mentioned
above, heat becomes difficult to be conducted at the molding
portion which forms the feeding head forming space.
Accordingly, in the case that this molding device is
used, there can be obtained an excellent heat insulation of
the feeding head.
Furthermore, in the molding device of this
invention, as a space between the contact surfaces of the
annular molding members and a space between the contact sur-
faces of the annular molding member and disc-shaped molding
member can be utilized as degasing means when a hot melt is
poured and the annular molding member and disc-shaped molding
member can be independently moved, it can be arranged such
that a film of the hot melt can easily be destroyed by giving
vibration.
One embodiment will be described with reference to
Figs. 8 and 9.
In Fig. 8, M denotes a mold for molding a wheel cap
C which comprises a combination of a lower mold 1 and an upper
mold 3. This mold M has a wheel cap-shaped molding space 4.
Also, 422 denotes a hot melt port which is formed on the upper
mold 3. Similarly, 42 denotes a hot melt passage which is
formed in the upper mold 3 and on a border surface between the
upper mold 3 and the lower mold 1. This hot melt 42 is
continuous to the hot melt port 422 and opened up at the cast-
-14-
- - 1 337234
ing space 4.
Next, 412 denotes a casting mark forming portion
which is formed on an upper wall surface of the casting space
4. This casting mark forming portion 4 is designed as such
that a mark of "ABC" is printed out on the surface of the
wheel cap C (Fig. 9).
Next, 51 denotes an auxiliary space which is formed
in the upper mold 3. This auxiliary space 51 is opened up in
the vicinity of the casting mark forming portion 412 in the
casting space 4. That is, the border surface between the
auxiliary space 51 and the casting space 4 is positioned in
the vicinity of the mark forming portion 412. 512 denotes an
air vent which is mounted on an opening end of the auxiliary
space 51. This air vent 512 is adapted to prevent the hot
melt from entering into the auxiliary space 51. 53 denotes a
pressurized fluid inlet hole which is formed in the upper mold
3. This pressurized fluid inlet hole 53 is communicated with
an upper end portion of the auxiliary space 51. 8 denotes a
connecting pipe which is inserted in the pressurized fluid
inlet hole 53. Through this connecting pipe 8, the pressuriz-
ed fluid inlet hole 53 and the gas pipe 81 are connected with
each other.
Next, the operation of such constructed marking
means will be described.
First, a hot melt is poured into a casting space
through the hot melt port 422 and the hot melt port 42. And,
after a hot melt is filled into the casting space 4, a
1 337234
-
pressurized gas is fed into the auxiliary space 51 through the
pressurized fluid inlet hole 53 to raise the internal pressure
of the auxiliary space 51. Then, the surface S of the hot
melt which now reaches the lower end portion of the auxiliary
space 51 (see Fig. 9) is pressurized. As a result, as the hot
melt in the vicinity of the auxiliary space 51 is strongly
pushed against the wall surface of the casting space 4, the
hot melt is also strongly pushed against the casting mark
forming portion 412. As a result, a casting mark is clearly
formed thereon.
As the marking means is such constructed as mention-
ed above, when a pressurized gas is introduced into the
auxiliary space after the hot melt is poured into the casting
space, the internal pressure of the auxiliary space
pressurizes the surface of the hot melt (the border surface
with respect to the auxiliary space). As a result, as the hot
melt in the vicinity of the auxiliary space is strongly pushed
against the wall surface of the casting space, the hot melt is
also strongly pushed against the mark forming portion.
Therefore, if this marking means is used, even a
tiny mark, for example, can clearly be printed out.
One embodiment will now be described with reference
to Fig. 10.
In Fig. 10, M denotes a main body of a mold for
molding a vehicle wheel. The mold main body M comprises a
combination of a lower mold 1, horizontal molds 2, 2, and an
upper mold 3. The lower mold 1 is supported by a supporting
-16-
1 ~37234
device 114. 4 denotes a casting space which is formed in the
mold main body M. This casting space 4 has a configuration
like a vehicle wheel, and comprises a disk forming space
portion 451, a spoke portion forming space portion 452, and a
rim forming space portion 453. Next, 11 denotes a nest of the
lower mold 1. The nest 11 forms the outer surface of the disk
portion (of the vehicle wheel). Also, 31 denotes a nest of
the upper mold 3. The nest 31 forms the rear surface of the
disk portion (of the vehicle wheel).
Next, 611 denotes a primary cooling hole formed in
the lower mold 1, and 612 denotes an auxiliary cooling hole
formed in the nest 11. By refluxing a cooling fluid, for
example, a cooling water, into these cooling holes 611 and
612, the lower mold 1 and the nest (of the lower mold 1) 11 is
cooled.
Also, 42 denotes a hot melt passage which is formed
in the horizontal mold 2. This hot melt passage 42 is
continuous to the rim shaping space portion 453 through the
weir 42. A hot melt passed through the hot melt passage 42 is
fed into the casting space 4 through this weir 43. 41 denotes
a feeding head space continuous to the hot melt passage 42.
Next, 91 denotes a hot melt reserving furnace which
contains a hot melt therein. 92 denotes a feed hot melt pipe
which is mounted on the hot melt reserving furnace 91. An
upper end of the feed hot melt pipe 73 is communicated with
the hot melt passage 12 of the horizontal mold 2. According-
ly, when a pressurized air is flowed through the air hole 911
-17-
1 337234
to pressurize the surface of the hot melt D, the hot melt D is
pushed up through the feed hot welt pipe 73 and poured into
the casting space 4 through the hot melt passage 42. 93
denotes a bellows disposed between the hot melt reserving
furnace 91 and the feed hot melt pipe 73, and 94 denotes a
heater for maintaining the hot melt D in a constant tempera-
ture.
Also, as shown in Fig. 11, the weir 43 may be opened
up at the connecting portion between the spoke portion forming
space 452 and the rim portion forming space 453.
As the casting device of a vehicle wheel is so con-
structed as mentioned above, cooling means can be disposed at
a lower portion of the casting space. As a result, as the hot
melt passes through a place which is away from the cooling
device, the hot melt can easily be maintained in a constant
temperature.
Also, as the main body of the mold is provided at a
portion for forming a disk thereof with a partially and
separate forced cooling means, the disk portion can
sufficiently be cooled.
Accordingly, if a casting device of a vehicle wheel
is used, there can be obtained a vehicle wheel, in which no
casting defect can be found, casting structure is minute, and
the strength of the disk portion is improved.
Fig. 12 shows another embodiment. This embodiment
differs only from the embodiment of Fig. 10 in the respect
that a plurality of feed hot melt pipes 73, 73 are
-18-
- - 1 337234
provided, and these pipes 73, 73 are communicated with a rim
forming space portion 453 through the hot melt passages 4, 42
and weirs 42, 42. Therefore, as time for pouring the hot melt
can be shortened, productivity can be improved.
Fig. 13 shows another embodiment. In this figure,
the lower mold 3 corresponds to an alternate design outer side
mold. The upper mold 3 corresponds to a design rear side
mold, and the horizontal mold 2 corresponds to a rim outer
side mold. 7 denotes hot melt flow passage changing means
(auxiliary type). one end of the hot melt fluid passage is
communicated with the hot melt port 222 and the other end
thereof is communicated with a hot melt inlet port 223 opened
up underneath. Also, this hot melt inlet port 223 is connect-
ed with the stock 73 through the flat plate-shaped filter 94.
Furthermore, the hot melt flow passage changing means 7 is
mounted as such that the means 7 can be interlocked with the
upper mold (disk rear side mold) 31 and the upper mold (design
rear side mold) 3.
Accordingly, the casting device of a vehicle wheel
exhibits the following technical effects. As a large space is
available in the vicinity of the disk portion, the disk
portion can sufficiently be cooled. As a result, the
structure of the disk portion of the vehicle wheel which is
obtained by means of casting can be miniaturized, and the
strength thereof can be improved. Also, as hot melt flow
passage changing means communicated with the hot melt port is
disposed on the outer peripheral surface of the rim, for
-19-
- 1 337234
example, by removing only the thin plate-shaped hot melt
passage portion from the mold first, an occurrence of bending
or separation of the thin plate-shaped hot melt passage
portion can be prevented.
Fig. 14 shows another embodiment. This embodiment
is characterized in that a hot melt reserving furnace 91 is
connected with a main body M of a mold.
Accordingly, in this mold of a vehicle wheel, cast-
ing productivity can be improved, and heat losses of a hot
melt within the hot melt reserving furnace can be m; ni m;zed.
Fig. 15 shows another embodiment in this embodiment
that adjacent weirs of the mold M are communicated with each
other.
Accordingly, in this mold of a vehicle wheel, heat
losses of the hot melt can be minimized, and the casting
device can be miniaturized.
Figs. 16 through 20 show another embodiment.
M denotes a main body of a mold for molding a
vehicle wheel. The mold main body M comprises a combination
of a lower mold 1, horizontal molds 2, 2, and an upper mold
3. The lower mold 1 is supported by a supporting device 114.
4 denotes a casting space which is formed in the mold main
body M. This casting space has a shape like a vehicle wheel
and comprises a disk shaping space portion 451, a spoke
portion shaping space portion 452, and a rim shaping space
portion 453. Next, 11 denotes a first nest of the lower mold
1 which is secured to the central portion of the lower mold 1
-20-
1 337234
by a bolt 12. This first nest 11 forms the outer surface of a
disk portion (of the vehicle wheel). Similarly, 111 denotes a
second nest of the lower mold 1 which is secured to the outer
surface of the first nest 11 also by the bolt 12. This second
nest 111 forms an axle hole of the vehicle wheel. Also, 31
denotes a nest of the upper mold 3. The nest 31 is inserted
in the central portion of the upper mold 3. This nest 31
forms a rear surface of the disk portion (of the vehicle
wheel).
Next, 42 denotes a hot melt passage which is formed
in the horizontal mold 2. This hot melt passage 42 is
continuous to the rim shaping space portion 453 through the
weir 43. The hot melt, which passed the hot melt passage 42,
is fed into the casting space 4 through the weir 43. 41
denotes a feeding head space.
Next, in Figs. 17 and 20, 613, 613,...denote
straight holes which are formed in the lower mold 1. These
straight holes 613, 613,...are blocked at the end portions
with blind plugs 615, 615,...and annularly communicated with
each other to form a primary cooling flow passage 611 which
are referred to as the "primary cooling means" in the claims.
617 and 617 denote connecting holes which are formed in the
lower mold 1 in the vertical direction (see Fig. 5). Each of
these connecting holes 617, 617 is communicated with the end
portion of the primary cooling flow passage 611. Through
these connecting holes 617, 617, a cooling water is fed into
the primary cooling flow passage 611 to forcefully cool the
-21-
- 1 337234
lower mold 1 and thus the mold main body M.
Next, in Figs. 17 through 19, 614, 614 denote
auxiliary straight holes which are formed in the first nest
11. These auxiliary straight holes 614, 614,...are blocked at
the end portions thereof with blind plugs 616, 616,...and
annularly communicated with each other to form a first
auxiliary cooling flow passage or "auxiliary cooling means" in
the claims. 618 and 618 denote connecting holes which are
formed in the first nest 11 in the vertical direction (see
Fig. 5). Each of these connecting holes 618, 618 is
communicated with the end portion of the first auxiliary cool-
ing flow passage 612. Through these connecting holes 618,
618, a cooling water is fed into the first auxiliary cooling
flow passage 612 to forcefully cool the first nest 11 and thus
mold main body M.
Next, in Figs. 17, 18 and 20, 813 denotes a vertical
hole which is formed between the connecting holes (of the
primary cooling flow passage 611) 617, 617 in the lower mold
1. This vertical hole 813 is disposed in the vicinity of the
weir 43 and is provided with a cooling device 815 secured
thereto by screw means. This cooling device 815 has a nozzle
816 and jets a cooling fluid such as, for example, a cooling
water into the vertical hole 813 through the nozzle 816. 817
denotes a water discharging port of the cooling device 815.
Similarly, 814 denotes a horizontal hole which is formed in
the vicinity of the weir 43 at the side surface of the lower
mold 1. This horizontal hole 814 is blocked at its opening
-22-
- 1 33~234
end with a blind plug 818 and communicated at its end portion
with the vertical hole 813. The vertical hole 813, the
horizontal hole 814, and the cooling device 815 define the
second auxiliary cooling flow passage 812 referred to as the
"cooling means" in the claims. When cooling water is fed
through the vertical hole 813, area in the vicinity of the
weir 43 of the lower mold 1 can concentratedly be cooled.
As the casting device of a vehicle wheel is so con-
structed as mentioned above, a hot melt within the rim shaping
space which is in the vicinity of the weir can more effective-
ly be cooled than a hot melt elsewhere.
Accordingly, if this mold of a vehicle wheel is
used, even when a weir is formed in the rim shaping space
portion, a hot melt forming these portions can generally
simultaneously be hardened with a hot melt forming other
portion. As a result, the structure of a vehicle wheel, which
is to be cast, becomes uniform and thus, the rigidity thereof
becomes uniform.
As a method for casting a vehicle wheel is carried
out as mentioned above, the structure of a vehicle wheel
obtained by means of casting can be miniaturized.
Accordingly, in this casting method, as only the hub
portion is forcefully cooled, when a vehicle wheel is cast,
the strength of a bolt hole in the hub portion can easily be
obtained at low cost.
As a method for casting a vehicle wheel is carried
-23-
- 1 337234
out as mentioned above, by cooling effects owing to the
auxiliary cooling means, it is difficult to be conducted to
other mold portion. As a result, the casting of the vehicle
wheel can easily be practiced.
When the auxiliary cooling means is disposed at a
lower part of a bolt hole predetermined portion of the vehicle
wheel, the bolt hole predetermined portion can partly be cool-
ed.
One embodiment of a vehicle wheel will be described
with reference to Fig. 23.
As an indication of a size in a microstructure of a
-24-
1 337234
casting of an aluminum casting lump, a dentrite arm spacing (DAS) is
measured.
The dentrite in an aluminum alloy, as schematically shown in Fig. 21,
has a secondary branch (secondary arm) growing at each side of a main shaft
(k). By measuring DAS, a distance (N) between the secondary arms can be
measured, in some cases, a cell size of the secondary arm (cell size of the
dentrite, that is, DCS) is measured.
The measurement of the DAS, as shown in Fig. 22, is obtained by
means of a secondary branch method, in which a plurality of values are
obtained by dividing a distance between a plurality of secondary arms with the
number of the secondary arms included in the distance and such obtained
plurality of values are expressed in an average value.
Fig. 23 is a sectional view obtained by cutting a vehicle wheel P by a
plane including a wheel rotational shaft. A rim barrel portion (p6) and a rim
carrying portion (p3) of a disk portion are strongly acted by a deflection
moment during rotation of the wheel. Therefore, this portion is required for
a casting to be high in strength.
It is generally understood that the strength of a casting is high, if the
crystal of the dentrite is minute.
Accordingly, this follows that one with a small measured value of DAS
is high in strength. Therefore, the DAS measured values of the rim barrel
portion (p6) and the rim
. . --
1 337234
carrying portion (p3) in the disk portion are preferably small.
The jointing portion (pS) between the rim portion and the disk portion
necessarily become large in thickness in view of casting, and therefore, and
cooling ofthe hot melt is delayed. As a result, the crystal ofthe dentrite becomes
somewhat coarse. However, the crystal is preferably small as much as possible.
The following is a summary of preferable conditions in view of behavior
of such wheel.
(~;) The Measured value of DAS of the rim end portion at the side of
the opposite disk ofthe wheel is smaller than the MEAsured value of DAS of the
rim barrel portion.
t~) The Measured value of DAS ofthe rim carrying portion ofthe disk
portion is smaller than the measured valve of DAS of the central portion of the
disk.
(~) The measured value of DAS ofthe rim carrying portion ofthe disk
portion is equal to the DAS value of the rim barrel portion or smaller than the
measured value of DAS of the rim barrel portion.
One which satisfies the above conditions is preferable. A vehicle wheel
having such value is high in strength at its required portion.
The DAS measured values in the vehicle wheel were as shown in Table
1.
Sample No. 1-1 a- 1 is the measured value of DAS of the central portion of
the disk of the wheel and is the measured value of the first one corresponding to
a portion of the weir front according to the casting bill.
Sample No. 1-la-2 is the measured value of DAS of an intermediate
portion (p2) of the disk of the wheel and is the measured value of the first onecorresponding to a portion of the weir front according to the casting bill.
- 26
~ 337234
Sample No. 1-la-3 is the measured value of DAS of the rim carrying
portion (p3) ofthe disk portion ofthe wheel and is the measured value ofthe first
one corresponding to the front weir according to the casting bill.
Sample No. 1-la-4 is the measured value of DAS ofthe rim end portion
(p4) of the disk side at the rim portion of the wheel and is the measured value of
the first one corresponding to a portion of the weir front according to the casting
bill.
Sample No. 1-la-5 is the measured value of DAS of the jointed portion
(p5) between the disk portion and the rim portion of the wheel and is the
measured value of the first one corresponding to a portion of the weir front
according to the casting bill.
Sample No. 1-la-6 is the measured value of DAS ofthe rim barrel portion
(p6) of the wheel and is the measured value of the first one corresponding to a
portion of the weir front according to the casting bill.
Sample No. 1-la-7 is the measured value of DAS of a portion (p7) of an
intermediate position between the rim barrel portion and the rim end portion of
the opposite disk side at the rim portion of the wheel and is the measured valueof the first one corresponding to a portion of the weir front according to the
casting bill.
Sample No. 1-la-8 is the measured value of DAS of the rim end portion
(p8) of the opposite disk side of the wheel and is the measured value of the
second one corresponding to a portion of the weir front according to the castingbill.
In the same manner, the sample number " 1 " in the first portion represents
a sample of the vehicle wheel of the present invention, the sample number " 1 "
in the middle position represents one corresponding to a portion of the weir front
according to the casting bill and likewise "2" represents one corresponding to a
1 337234
portion rotated at 90C from the weir front according to the casting bill, and the
sample numbers " 1 " in the last position represents one of the central portion (pl)
ofthe disk, likewise "2" represents one ofthe middle portion (p2) ofthe disk, "3"
represents the rim carrying portion (p3) of the disk portion of the wheel, "4"
represents the rim end portion (p4) of the disk side at the rim portion nearest
from the disk portion, "5" represents the jointed portion (p5) between the disk
portion and the rim portion, "7" represents the rim barrel portion (p6), "7
represents the portion of the intermediate position between the rim barrel portion
and the rim end portion, and "8" represents the rim end portion (p8) of the
opposite disk side, and the characters "a" and "b" in the middle position
respectively represent the first and second ones of samples collected from the
same position of a plurality of vehicle wheels of the present invention.
Also, the number "2" in the first position represents the conventional
vehicle wheel according to a low pressure casting method as a comparison
example and similarly, "3" represents the conventional vehicle wheel according
to a gravity casting method as a comparison example.
And, the shock test results and the rotary bending test results ofthe sample
vehicle wheels picked up from a vehicle wheel group which has such measured
values were excellent compared with those of the comparison examples of the
conventional vehicle wheels.
Accordingly, a vehicle wheel of the present invention not only satisfies
the safety standard but also ensures uniformity with high performance.
As described in the foregoing, according to the present invention, there
can be provided a vehicle wheel in which there can be estimated a performance
behavior for each part which was unable to make clear by a macrotest
observation as a whole wheel such as a shock test or a rotary bending test of a
wheel. Therefore, the present invention greatly contributes to the development
of industry.
28
Tablel l 337234
sample DAS measured sample DAS measured sample DAS measured
No. values No. values No. values
l-la-8 26 ~1 m 1-lb-8 24 '~1 m 1-2a-8 26 ~1 m
l-la-7 29 ~1 m 1-lb-7 30 ~1 m 1-2a-7 29 ~1 m
l-la-8 34 ~ m 1-lb-6 32 ~1 m 1-2a-6 29 ~1 m
l-la-S 36 11 m l-lb-S 30 ~1 m 1-2a-5 30 ~L m
l-la-4 26 ~ m 1-lb-4 25 11 m 1-2a-4 24 ~1 m
l-la-3 26 '~1 m 1-lb-3 25 ~1 m 1-2a-3 29 ~1 m
l-la-2 33 ~1 m 1-lb-2 33 ,u m 1-2a-2 35 ~ m
l-la-l 38 ~1 m l-lb-l 33 ~1 m 1-2a-1 35 ~1 m
1-2b-8 25 ~ m 2-1-8 23 11 m 3-1-8 46 ~1 m
1-2b-7 27 ~1 m 2-1-7 28 ~1 m 3-1-7 42 ~ m
1-2b-8 29 ,um 2-1-6 29 ~ m 3-1-6 33 llm
1-2b-5 29~1m 2-1-5 35~1m 3-1-5 30~1m
1-2b-4 22 ~1 m 2-1-4 22 ~1 m 3-1-4 20 ~ m
1-2b-3 27 ~1 m 2-1-3 37 ~ m 3-1-3 30 ~ m
1-2b-2 3011m 2-1-2 40~1m 3-1-2 30~1m
1-2b-1 31 ~1 m 2-1-l 40 11 m 3-1-1 35 ~1 m
29
