BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] FIG. 3 shows a delivery pipe for supplying fuel to an engine. The delivery pipe has
an axially elongate longitudinal hole h and a plurality of transversal holes e1 to
e4 communicating with the longitudinal hole h in a substantially normal direction
thereto. Injectors are mounted in the transversal holes e1 to e4.
[0002] This invention relates to a process of casting a pipe with a transversal hole, i.e.,
a pipe having an elongate longitudinal hole and at least one transversal hole communicating
with the longitudinal hole in a substantially normal direction thereto like the delivery
pipe noted above and a casting die used for the same casting process.
2. Description of the Prior Art
[0003] A casting process for casting a pipe having an elongate longitudinal hole is well
known in the art. In such a process, a center pin for forming the longitudinal hole
is positioned in a cavity before charging molten metal thereinto. The longitudinal
hole is formed in the casting product by withdrawing the center pin therefrom after
the solidification of the molten metal.
[0004] In this technique, increasing the length of the center pin gives rise to a problem
of the displacement and deformation of the center pin during the casting process.
The problem is pronounced in case where the center pin is positioned like a cantilever
in the cavity, that is, where a casting product having a longitudinal hole closed
at one end is cast. Techniques for preventing the displacement and deformation of
the center pin have been proposed, as disclosed in Japanese Laid-open Patent Publication
No. 59-189062 and Japanese Laid-open Patent Publication No. 61-9959. In both these
techniques, a core pipe is used and is left in the casting product, so that the shape
accuracy of the longitudinal hole is maintained.
[0005] FIG. 11 shows the technique disclosed in the Japanese Laid-open Patent Publication
59-189062. Designated at 6 is a core pipe which is positioned in a cavity 4. A pair
of center pins 8a and 8b are inserted downward and upward into the core pipe 6. In
this state, molten metal is charged into the cavity 4. With the solidification of
the molten metal, the core pipe 6 is cast in the eventual casting product, i.e., the
core pipe 6 is left in the casting product. Afterwards, the pair center pins 8a and
8b are withdrawn from the core pipe 6.
[0006] In the technique disclosed in the Japanese Laid-open Patent Publication No. 61-9959,
only the core pipe is used, that is, no center pin is used. To position the core pipe
in the cavity, the core pipe is provided with a projections projecting from its outer
periphery. The projections are held in contact with a cavity formation surface. Afterwards,
molten metal is charged into the cavity. With the solidification of the molten metal,
the core pipe is cast in the casting product.
[0007] As shown above, by the use of a core pipe, it is possible to obtain a casting product
having an elongate longitudinal hole. Particularly, according to the technique disclosed
in the Japanese Laid-open Patent Publication 61-9959, it is possible to ensure a sufficiently
long longitudinal hole closed at one end. When the core pipe is cast in the casting
product, however, it is necessary to produce core pipes in number corresponding to
the number of casting products, and this increases the cost of manufacture. Further,
when it is desired to obtain a continuous integral casting product as overall produce,
it is impossible to use any core pipe. When a process of forming a longitudinal hole
without use of any core pipe but by using a center pin is adopted, on the other hand,
there is the problem of center pin displacement and deformation, lhus imposing restriction
on the length of the obtainable longitudinal hole.
[0008] From the FR-A-2637322, a casting die and a casting process for producing a fuel manifold
for a fuel injection system of an internal combustion engine is known. By means of
this process, a die cast product is achieved consisting of one piece from molten metal
material which is injected under pressure into a mold. The cast die product constitutes
a blank which has to be processed afterwards. In particular, it comprises substantially
a tubular element being open on both sides and further having sleeves along the longitudinal
side of the tubular element which are accommodated forming an angle less than 90°
with the axis of the axial hole of the longitudinal tubular element. The sleeves are
in communication with the axial hole of the longitudinal tubular element.
[0009] It is an object of the present invention, to achieve a casting die for casting a
pipe with transversal holes and a casting process for casting such a pipe with transversal
holes without use of any core pipe, while also avoiding the displacement and the deformation
of the center pin.
[0010] According to the invention, a casting process according to claim 1 and a casting
die according to claim 3 is used. With the above casting process and casting die,
molten
[0011] metal is charged and solidified with the center pin side surfaces positioned between
the end faces of the pair of mandrel pins. It is thus possible to prevent the displacement
and deformation of the center pin and ensure high shape accuracy of the longitudinal
hole. In the above process, when the center pin is held in a cantilever support in
the die cavity, the end of the center pin is suitably supported by the pair of mandrel
pins. When the center pin is held in the cavity in its state of support at its opposite
ends, its central portion is suitably supported by the pair of mandrel pins.
[0012] The above means, although very effective when casting a pipe having a pair of transversal
holes, is difficult to carry out when the number of transversal holes is less than
one pair. In such a case, the process according to claim 2 and the casting die according
to claim 5 is used.
[0013] That is, the end face of one mandrel pin is held in contact with a side surface of
the center pin at least to prevent the center pin from being displaced toward that
mandrel pin. This means alone, however, can not prevent the center pin from the displacement
thereof away from the mandrel pin. Accordingly, in this process, molten metal is charged
into the cavity toward the mandrel pin. When this is done so, the molten metal being
charged pushes the center pin toward the mandrel pin and thus prevents the displacement
thereof away from the mandrel pin. In this way, it is possible to cast a pipe having
at least one transversal hole with satisfactory degree of shape accuracy.
[0014] According to the invention, it is possible to obtain a casting product which is integral
and a one-piece casting as a whole and in which the surfaces of the longitudinal hole
and the transversal hole are cast skin surfaces. This casting product has satisfactory
shape accuracy of the cast skin of the longitudinal hole, and it can be used as such.
That is, there is no need of mechanically machining the cast skin to ensure accuracy,
and thus, the product can be manufactured inexpensively.
[0015] The product can be suitably used as a delivery pipe. In this case, the longitudinal
hole is used as a fuel path, and the transversal hole as an injector mounting hole.
Such delivery pipes can be manufactured inexpensively in a large number by casting.
[0016] Further advantageous improvements of the present invention is the subject-matter
according to the dependent claims.
[0017] The present invention will be more fully understood from the following detailed description
and appended claims when taken with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018]
FIG. 1 is a fragmentary sectional view showing a casting die for carrying out a process
of casting a pipe with transversal holes according to a first embodiment of the invention;
FIG. 2 is a fragmentary sectional view taken along arrow line II-II in FIG. 1;
FIG. 3 is a side view showing a delivery pipe as a product of casting;
FIG. 4 is an elevational view, partly in section, showing the casting die for carrying
out the process of casting a pipe with transversal holes according to the first embodiment
of the invention;
FIG. 5 is a view substantially taken along arrow line V-V in FIG. 4;
FIG. 6 is a fragmentary sectional view, partly broken away, showing a mandrel pin
and push-out pins in detail;
FIG. 7 is a view similar to FIG. 1 but showing a second embodiment of the invention;
FIG. 8 is a view similar to FIG. 2 but showing the second embodiment;
FIG. 9 is a view similar to FIG. 8 but showing a third embodiment of the invention;
FIG. 10 is a view showing a different example of the relation between a mandrel pin
and push-out pins from that shown in FIG. 6;
FIG. 11 is a fragmentary sectional view showing a casting die for carrying out a prior
art pipe casting process; and
FIGS. 12(A) and 12(B) are fragmentary sectional views showing a relation between a
return pin and a push-out pin in the prior art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Now, a process for casting a pipe with transversal holes according to a first embodiment
of the invention will be described with reference to FIGS. 1 to 6. In this embodiment,
the pipe w with transversal holes to be cast is a delivery pipe with an injector mounted
therein for supplying fuel to an engine. The pipe is shown in side view in FIG. 3.
[0020] The delivery pipe w has an axially elongate longitudinal hole h which extends in
the axial direction and which is utilized as a fuel path, and has injector mounting
transversal holes e1 to e4 communicating with the longitudinal hole h in a substantially
normal direction thereto and formed at a uniform interval in the longitudinal direction.
Further, the delivery pipe w has a pressure regulator mounting transversal hole p
formed in its end portion and communicating with the longitudinal hole h in a substantially
normal direction thereto and on the side opposite the injector mounting transversal
hole e4.
[0021] FIG. 4 is an elevational view, partly in section, showing a casting die 10 for forming
the delivery pipe w by the casting process according to this embodiment. FIG. 1 is
a view showing a part of FIG. 4 in detail. FIG. 2 is a view taken along arrow line
II-II in FIG. 1. FIG. 5 is a view taken substantially along arrow line V-V in FIG.
4. In the following description, the die width direction is referred to as X-axis
direction, the die height direction as Y-axis direction, and the die closing direction
(i.e., direction of movement of a movable die) as Z-axis direction.
[0022] The casting die 10 comprises a fixed die 12 provided with a fixed insert member 120,
and a movable die 14 provided with a movable insert member 140. As shown in FIG. 4,
in the closed state of the casting die, product formation spaces, i.e., cavities 15,
are formed elongatedly in the longitudinal direction (i.e., Y-axis direction) between
the fixed insert member 120 and the movable insert member 140. In this embodiment,
as shown in FIG. 5, six cavities 15 are formed in juxtaposition in the width direction
of the casting die 10 (i.e., X-axis direction).
[0023] In a lower portion of the fixed die 12, a sleeve 12s is provided such that it extends
in the Z-axis direction, and molten metal injected by a plunger tip (not shown) from
the sleeve 12s is led through molten metal paths 12t (see FIG. 5) to be charged into
the cavities 15. The sectional area of the molten metal paths 12t is set such that
it is reduced as one goes away from the sleeve 12s, that is, such that sectional area
A1 > sectional area A2 > sectional area A3. With this arrangement, the charging rate
of the cavity 15 at the end on the side of the vehement charging with the momentum
of molten metal is suppressed to a certain extent, thus substantially uniforming the
charging time of the individual cavities 15.
[0024] In the fixed die 12, a mandrel pin 12r for forming the pressure regulator mounting
transversal hole p in the delivery pipe w is mounted for each cavity 15. The mandrel
pin 12r is positioned such that its axis is parallel to the Z-axis. As shown in FIGS.
1 and 2, its end face projects by a prescribed dimension from a cavity formation surface
15s of the fixed insert member 120. Further, its end face is formed with an arcuate
recess 12u such as to be substantially in close contact with a side surface of a center
pin 24 to be described later.
[0025] The movable die 14 is coupled via a die base 18 to a drive unit (not shown), and
with the driving thereof, it is moved in the Z-axis direction from a position to close
the die to a position to open the die or vice versa. To the top of the movable die
14 is secured a center pin insertion cylinder 20 for moving a movable unit 21 in the
Y-axis direction (i.e., vertical direction). On the movable unit 21 of the center
pin insertion cylinder 20 is mounted a support block 22 supporting center pins 24.
Each center pin 24 is a mandrel pin for forming the longitudinal hole h in the delivery
pipe w, and is mounted in the support block 22 for movement in the vertical direction
along the center line of each cavity 15. The support block 22 has a raised portion
22t which is engaged in a recessed portion 12h of the fixed die 12 when the casting
die is closed, thus preventing the support block 22 from being pushed back upward
by high pressure applied to the interior of the cavities 15.
[0026] The movable die 14 is provided with two sets of center pin insertion cylinder 20
and support block 22. Three center pins 24 are raised and lowered simultaneously by
one set of center pin insertion cylinder 20 and so forth.
[0027] As shown in FIGS. 1 and 4, in the movable die 14, four movable mandrel pins 14r1
to 14r4 for forming the injector mounting transversal holes e1 to e4 in the delivery
pipe w, are provided for each cavity 15. The movable mandrel pins 14r1 to 14r4 are
movable at right angles to the center pin 24 (i.e., Z-axis direction) and are moved
axially by drive cylinders (not shown). Their end faces are each formed with an arcuate
recess 14u to be substantially in close contact with a side surface of the center
pin 24.
[0028] The movable mandrel pins 14r1 to 14r4, the fixed mandrel pins 12r and the center
pins 24 all have their surfaces provided with TD treatment, P-CVT treatment, etc.
for the seizure prevention purpose.
[0029] FIG. 6 shows the detailed structure of the mandrel pin 12r on the side of the fixed
insert member 120. The fixed insert member 120 has a space 42s in which is accommodated
a push-out member 44 having a pair of push-out pins 44p and 44q and a mandrel pin
12r.
[0030] The mandrel pin 12r is mounted on the center of the push-out member 44 such that
it extends at right angles thereto, and the pair push-out pins 44p and 44q are provided
in right angles around the mandrel pin 12r. The mandrel pin 12r and the push-out pins
44p and 44q are inserted in through holes 120k, 120h and 120i for axial movement through
the same in a horizontal state. The space 42s is closed by a retainer member 42, and
a spring member 44b biasing the push-out member 44 away from the retainer member 42
is mounted between the retainer member 42 and the push-out member 44. Thus, in the
open state of the casting die, the push-out member 44 pushed by the spring force of
the spring member 44b is held at a right set position in FIG. 6. In this state, the
projection of the mandrel pin 12r and the push-out pins 44p and 44q from the fixed
insert member 120 is maximum. The lengths of the push-out pins 44p and 44q and the
mandrel pin 12r are set such that when the die closing is completed, the ends of the
push-out pins 44p and 44q are substantially in accord with the position of the surface
of each cavity 15 with the recessed end 12u of the mandrel pin 12r in contact with
a side surface of the center pin 24.
[0031] Now, the process of casting a pipe (or delivery pipe w) with transversal holes according
to this embodiment will be described.
[0032] First, in the open state of the casting die, the movable unit 21 is lowered with
the operation of the center pin insertion cylinder 20 of the movable die 14. As a
result, the center pin 24 is lowered along a center line of each cavity 15 to be positioned
at a predetermined position. Then, each of the movable mandrel pins 14r1 to 14r4 is
moved by a drive cylinder to be projected by a prescribed dimension from each cavity
formation surface 15m of the movable insert member 140. With the movable mandrel pins
14r1 to 14r4 projected from each cavity formation surface 15m of the movable insert
member 140, a clearance of about 0.3 mm is provided between the end recess 14u of
each of the movable mandrel pins 14r1 to 14r4 and a side surface of each center pin
24. The end face 14u of each of the mandrel pins 14r1 to 14r4 and the side surface
of each center pin 24 need not be in perfectly close contact with each other, but
they may face each other with a slight clearance therebetween.
[0033] Then, the casting die is closed with the movable die 14 and the die base 18 moved
by the drive unit, as shown in FIGS. 1 and 4. Thus, the cavities 15 are formed between
the fixed insert member 120 and the movable insert member 140. Further, the side surface
of each center pin 24 is brought into contact with the recessed end 12u of the mandrel
pin 12r to contract the spring member 44b and cause retreat of the mandrel pin 12r.
At this time, the push-out pins 44p and 44q are also retreated to be flush with the
cavity formation surface. When the closing of the casting die is completed in this
way, molten metal injected from the sleeve 12s through the plunger tip is charged
into each cavity 15 through each molten metal path 12t. When the molten metal is solidified
after the lapse of a predetermined period of time, the casting die is opened again
with the movable die 14 and the die base 18 moved by the drive unit. Further, each
center pin 24 is taken out with the driving of each center pin insertion cylinder
20, and each of the movable mandrel pins 14r1 to 14z4 is taken out by the drive cylinder.
[0034] Since the sectional areas A1 to A3 of the molten metal paths 12t are set such as
above to provide for a substantially uniform molten metal charging time for each cavity
15, the molten metal solidification time does not fluctuate for each cavity 15, and
it is possible to set die opening timings satisfactorily.
[0035] With the movable die 14 separated from the fixed die 12 when the casting die is opened
after the casting, the pushing force from the center pin 24 is no longer applied to
the end of the mandrel pin 12r, and the push-out member 44 is moved away from the
retainer member 42 by the spring force of the spring member 44b. As a result, the
push-out pins 44p and 44q project from the cavity formation surface of the fixed die
12. Thus, the product of casting is kicked out from the surface of the cavity 15.
[0036] As shown above, according to the process for casting the delivery pipe w of this
embodiment, in the closed state of the casting die 10, the end of the center pin 24
which is readily subject to displacement, is restricted radially by the recessed end
14u of the movable mandrel pin 14r4 and the recessed end 12u of the fixed mandrel
pin 12r. Thus, with application of a high pressure to the center pin 24 as a result
of forced charging of molten metal into the cavity 15, the end of the center pin 24
is not displaced radially, thus substantially eliminating the bending of the center
pin 24 during the casting. It is thus possible to eliminate such inconvenience as
failure of withdrawal of the center pin 24 after the solidification of molten metal.
This means that, unlike the prior art, there is no need of providing any particular
core pipe or the like for the reinforcement of the center pin 24. Further, since a
clearance of about 0.3 mm is provided between the side surface of the center pin 24
and the recessed end 14u of the movable mandrel pin 14r4, it is possible to absorb
thermal expansion of the center pin 24 and the movable mandrel pin 14r4 that is caused
during the casting.
[0037] In the casting die of this embodiment, the mandrel pin 12r also serves the role of
a return pin for causing the retreat of the push-out pins 44p and 44q to the cavity
formation surface.
[0038] FIGS. 12(A) and 12(B) show a prior art relationship between a push-out pin and a
return pin as disclosed in Japanese Laid-open Patent Publication No. 1-3141127.
[0039] This casting die 401 comprises a fixed die 412 mounted on a fixed die mounting member
402 and a movable die 413 mounted on a movable die mounting member 403. As shown in
FIG. 12(B), in the closed state of the casting die 401, a cavity 410 is formed therein.
Further, the movable die 413 has a space 413s in which a push-out member 414 is accommodated
for movement in the vertical direction in FIG. 12(B). The push-out member 414 has
a push-out pin 413p for kicking out a casting product from the surface of the cavity
410 at the time of the die opening and a return pin 413r for returning the end of
the push-out pin 413p to the position of the surface of the cavity 410 at the time
of the die closing. A spring member (not shown) is provided between the push-out member
414 and the movable die mounting member 403, and the push-out member 414 is biased
upward by the spring force. Thus, when the casting die 401 is open, the push-out pin
413p is projecting from the surface of the cavity 410 (movable die 413), while the
return pin 413r is projecting from the engagement surface 413m of the movable die
413.
[0040] With the above construction, when the end of the return pin 413r is brought into
contact with the engagement surface 412m of the fixed die 412 during the process of
approach of the fixed die 412 by the movable die 413 at the time of the die closing,
the return pin 413r is pushed into the movable die 413 to an extent corresponding
to the distance of approach of the fixed die 412 by the movable die 413. Thus, the
push-out member 414 is moved downward in FIG. 12(B) against the spring force. At this
time, in the perfectly closed state of the casting die 401, the push-out pin 413p
is returned to a position such that its end is substantially in accord with the surface
of the cavity 410.
[0041] With the movable die 413 separated from the fixed die 412 when the casting die is
opened after the casting, the push-out force from the fixed die 412 is no longer applied
to the return pin 413r. As a result, the push-out member 414 is moved upward in FIG.
12(A) by the spring force, and the push-out pin 413p projects from the surface of
the cavity 410 of the movable die 413. Thus, the product of casting is kicked out
from the surface of the cavity 410, that is, prevented from remaining on the cavity
surface.
[0042] With the above prior art casting die 401, however, the return pin 413r for returning
the push-out pin 413p to a predetermined position is provided at the position of the
engagement surface 413m of the movable die 413. This means that in the casting die
401, it is necessary to set the width of the engagement surface 413m constituting
the periphery of the cavity 410 by taking the space for mounting the return pin 413r
into consideration. In addition, it is necessary to set the area of the push-out member
414 supporting the push-out pin 413p and the return pin 413r to be greater than the
area of projection of the cavity 410. Therefore, a large space is necessary in the
casting die 410, thus increasing the size of the casting die 401 and also dictating
restrictions in the die design.
[0043] In contrast, with the construction shown in FIG. 6, the mandrel pin 12r also serves
the role of the prior art return pin 413r, and thus the outer shape dimensions of
the die are extremely reduced. In addition, while in the prior art, a clearance has
to be provided between the center pin 24 and the mandrel pin 12r by taking the thermal
expansion of the two pins into consideration, in this embodiment, no such clearance
has to be provided because the mandrel pin 12r is capable of being retreated.
[0044] A second embodiment of the invention will be described with reference to FIGS. 7
and 8.
[0045] FIG. 7 is a view similar to FIG. 1, and FIG. 8 is a sectional view taken along line
VIII-VIII in FIG. 7. Parts like those in the first embodiment are designated by like
reference numerals with addition of 100, and their detailed description will be omitted.
[0046] What is produced in this embodiment is the delivery pipe w described before in connection
with FIG. 3 with omission of the pressure regulator mounting transversal hole p. Without
the pressure regulator mounting transversal hole p, the center pin 24 can not be restricted
from the opposite sides with a mandrel pin. In the case of this embodiment, a center
pin 124 is supported from a single side by a single mandrel pin 114r4, as is obvious
from FIGS. 7 and 8.
[0047] In this case, the center pin 24 may be displaced away from the mandrel pin 114r4.
Accordingly, in this embodiment, a sprue R2 through which to charge molten metal into
the cavity 115 is provided at an angle with respect to a position to charge molten
metal toward the mandrel pin 114r4. With this arrangement, the charging pressure acts
in a direction of pushing the center pin 124 against the mandrel pin 114r4, and thus,
there is no possibility of displacement of the center pin 124 away from the mandrel
pin 114r4. Molten metal is further charged from a sprue R3 through a sprue R1 into
the cavity 115, and this charging pressure again acts on the side of pushing the center
pin 124 against the mandrel pin 114r4.
[0048] FIG. 9 shows a third embodiment. Again in this case, a sprue R5 and a mandrel pin
214r4 may not always face each other. In any case, molten metal being charged flows
toward the side of pushing a center pin 224 against the mandrel pin 214r4. Thus, the
center pin 224 is not displaced or deformed.
[0049] FIG. 10 shows a different example of the relation between a mandrel pin and push-out
pins.
[0050] In this embodiment, a casting die 320 comprises a fixed die 322 with a fixed insert
member 322j mounted therein and a movable die 323 with a movable insert member 323j
mounted therein. As shown in FIG. 10, a cavity 330 is formed in the die 320 when the
die is closed. Then, molten metal forced out from a sleeve 326 provided in the fixed
die 322 is charged through a molten metal path (not shown) into the cavity 330.
[0051] The fixed die 322 has a space 322s which is formed in the neighborhood of the back
side of the fixed insert member 322j, and in the space 322s is accommodated a push-out
member 324 with a push-out pin 324p and a mandrel pin 324n. The push-out pin 324p
serves to push out a casting product from the fixed insert member 322j after the casting,
and the mandrel pin 324n is used to form a through hole in the product.
[0052] The push-out member 324 has a mandrel pin 324n extending from and at right angles
to its center and also has a plurality of push-out pins 324p which are likewise mounted
by right angle mounting around the mandrel pin 324n. The mandrel pin 324n and the
push-out pin 324p are inserted in through holes 322h and 322k of the fixed die 322
and the fixed insert member 322j, so that the mandrel pin 324n and the push-out pin
324p can be moved axially in their horizontal position. The space 322s is closed by
a retainer member 322x. A spring member 324b biasing the push-out member 324 away
from the retainer member 322x is provided between the retainer member 322x and the
push-out member 324. Thus, in the closed state of the casting die, the push-out member
324 is held at a left set position in FIG. 10 by the spring force of the spring member
324b. Thus, the mandrel pin 324n and the push-out pin 324p are in maximum projection
from the fixed insert member 322j. The length of the mandrel pin 324n is set to be
greater than the length of the push-out pin 324p by an amount corresponding to the
thickness of the cavity 330.
[0053] Further, a push-out pin 327 for kicking out a casting product from the movable insert
member 323j after the casting, is mounted horizontally in the movable die 323 and
movable insert member 323j. Further, in the movable die 323 is accommodated a push-out
cylinder (not shown) for axially moving the push-out pin 327.
[0054] Now, the operation of the casting die 320 will be described.
[0055] First, during the approach of the movable die 323 toward the fixed die 322 when the
casting die is closed, the mandrel pin 324n is brought into contact with the cavity
surface of the movable insert member 323j. As this occurs, the movable insect member
323j pushes the mandrel pin 324n in the axial direction. As a result, the mandrel
pin 324n is forced into the fixed insert member 322j and the fixed die 322 by the
distance corresponding to the approach of the movable die 323 toward the fixed die
322, so that the push-out member 324 is moved toward the retainer member 322x against
the spring force of the spring member 324b. Then, as the push-out member 324 is moved,
the push-out pin 324p is received in the fixed insert member 322j. Since the length
of the mandrel pin 324n is set to be greater than the length of the push-out pin 324p
by an amount corresponding to the thickness of the cavity 330 as noted above, when
the die 320 is completely closed, the push-out pin 324p is retreated into the fixed
insert member 322j until its end is substantially in accord with the cavity surface
of the fixed insert member 322j.
[0056] Subsequently, molten metal is forced through the sleeve 326 and molten metal path
(not shown) into the cavity 330 for casting. With the movable die 323 separated from
the fixed die 322 when the casting die is opened after the casting, the pushing force
from the movable insert member 323j is no longer applied to the end of the mandrel
pin 324n, and the push-out member 324 is thus moved away from the retainer member
322x by the spring force of the spring member 324b. As a result, the push-out pin
324p is projected from the surface of the cavity wall of the fixed insert member 322j
to kick out the casting product from the surface of the cavity 330, that is, prevent
the product from remaining on the cavity wall. Further, in the movable die 323 the
push-out pin 327 is operated by a push-out cylinder (not shown) for separating the
casting product from the surface of the cavity 330.
[0057] As shown above, with the casting die 320 of this embodiment, the mandrel pin 324n
mounted on the push-out member 324 with the push-out pin 324p secured thereto, also
serves as a return pin. Thus, unlike the prior art, there is no need of disposing
any return pin at the position of the engagement surface of the cavity 330, thus permitting
the reduction of the width of the engagement surface. Further, since the mandrel pin
324n is disposed at a position to penetrate the cavity 330, the area of the push-out
member 324 supporting the mandrel pin 324n and the push-out pin 324p may be made smaller
than the area of projection of the cavity 30. Thus, the die may have a reduced space
for accommodation of the push-out member 324, thus permitting the die 320 to be made
compact.
[0058] According to the invention, molten metal is charged in a state such that the center
pin for forming a longitudinal hole in a pipe is restricted by the end face of the
mandrel pin for forming a transversal hole in the pipe. Thus, application of a high
molten metal pressure to the center pin during the casting does not cause displacement
or deformation of the center pin in the radial direction, and it is possible to substantially
eliminate the bending of the center pin. This eliminates the possibility of such inconvenience
as failure of withdrawal of the center pin. Further, since unlike the prior art, no
core pipe or the like is required, the cost of manufacture can be reduced.
[0059] Further, according to the invention, since the mandrel pin also has a role of a return
pin for returning the push-out pin, there is no need of disposing any return pin at
the position of the engagement surface of the cavity. Further, the area of the push-out
member supporting the mandrel pin and the push-out pin may be made smaller than the
area of projection of the cavity, thus permitting the reduction of the push-out member
accommodation space in the die. The casting die thus may be made compact.
1. Verfahren zum Gießen eines Rohrs (w), wobei das Rohr ein langgezogenes längliches
Loch (h) und zumindest ein Paar transversaler Löcher (p, e4) hat, die mit dem länglichen
Loch in einer im wesentlichen senkrechten Richtung dazu in Verbindung stehen, mit
den folgenden Schritten:
Positionieren eines stabförmigen Mittenstifts (24) zum Ausbilden des länglichen Loches
(h) in einer vorbestimmten Lagebeziehung zu einer einen Hohlraum ausbildenden Fläche
einer Gießform (10);
Positionieren eines Paars Dornstifte (12r, 14r4) zum Ausbilden des Paars transversaler
Löcher derart, daß eine Stirnfläche jedes Dornstifts in Kontakt mit einer Seitenfläche
des Mittenstifts (24) ist; und
Einfüllen von geschmolzenem Metall in den Formhohlraum (15), nachdem der Mittenstift
(24) und das Paar Dornstifte (12r, 14r4) positioniert worden sind, wobei
das Paar Dornstifte (12r, 14r4) angeordnet ist, um auf den Mittenstift (24) derart
zu wirken, daß seine radiale Bewegung beschränkt ist.
2. Verfahren zum Gießen eines Rohrs (w), wobei das Rohr ein langgezogenes längliches
Loch (h) und zumindest ein transversales Loch (p, e4) hat, das mit dem länglichen
Loch in einer im wesentlichen senkrechten Richtung dazu in Verbindung steht, mit den
folgenden Schritten:
Positionieren eines stabförmigen Mittenstifts (124) zum Ausbilden des länglichen Loches
(h) in einer vorbestimmten Lagebeziehung zu einer einen Hohlraum ausbildenden Fläche
einer Gießform (110);
Positionieren zumindest eines Dornstiftes (114r1 bis 114r4) zum Ausbilden des zumindest
einen transversalen Loches derart, daß eine Stirnfläche des Dornstiftes in Kontakt
mit einer Seitenfläche des Mittenstifts (124) ist; und
Einfüllen von geschmolzenem Metall in den Formhohlraum (115), wobei
das geschmolzene Metall in Richtung des Dornstiftes (114r4) eingefüllt wird, nachdem
der Mittenstift (124) und der Dornstift positioniert worden sind.
3. Gießform zum Gießen eines Rohrs (w), wobei das Rohr ein langgezogenes längliches Loch
(h) und zumindest ein Paar transversaler Löcher (p, e4) hat, die mit dem länglichen
Loch in einer im wesentlichen senkrechten Richtung dazu in Verbindung stehen, mit:
einem Mittenstift (24), der in einem Formhohlraum (15) zum Ausbilden des länglichen
Loches (h) angeordnet ist,
zumindest einem Paar Dornstifte (12r, 14r4), die in den Formhohlraum (15) hinein vorstehen,
um das zumindest eine Paar transversaler Löcher auszubilden, wobei die Position des
Mittenstifts (24) in der radialen Richtung dazu mittels Stirnflächen (12u, 14u) des
Paars Dornstifte (12r, 14r4) bei geschlossener Gießform (10) und mittels einer Anordnung
des Paars Dornstifte (12r, 14r4) zurückgezogen ist, die zum wirken auf den Mittenstift
(24) derart angeordnet sind, daß seine radiale Bewegung beschränkt ist.
4. Gießform nach Anspruch 3, weiter mit einem Ausdrückstift (44p, 44q) zum Trennen eines
darin hergestellten Gießprodukts von einer einen Hohlraum (15) ausbildenden Fläche,
wobei der Ausdrückstift starr mit einem der Paar Dornstifte (12r) gekoppelt ist.
5. Gießform zum Gießen eines Rohrs (w), wobei das Rohr ein langgezogenes längliches Loch
(h) und zumindest ein transversales Loch (e1-e4) hat, das mit dem länglichen Loch
in einer im wesentlichen senkrechten Richtung dazu in Verbindung steht, mit:
einem Mittenstift (124), der in einem Formhohlraum (115) zum Ausbilden des länglichen
Loches (h) angeordnet ist,
zumindest einem Dornstift (114r1 bis 114r4), der in den Formhohlraum (115) in einer
Richtung im wesentlichen senkrecht zu dem Mittenstift (124) zum Ausbilden des zumindest
einen transversalen Loches hinein vorsteht,
einem Einlauf (R1) zum Einfüllen von geschmolzenem Metall in den Formhohlraum (115),
einer Stirnfläche des Dornstifts (114r1 bis 114r4), die mit einer Seitenfläche des
Mittenstifts (124) bei geschlossener Gießform in Kontakt gebracht ist, wobei sich
der Einlauf (R2) und der Dornstift auf entgegengesetzten Seiten des Mittenstifts (124)
befinden.
1. Procédé de coulage d'un tube (w), le tube comportant un trou longitudinal allongé
(h) et au moins une paire de trous transversaux (p, e4) communiquant avec le trou
longitudinal suivant une direction pratiquement normale à celui-ci, comprenant les
étapes suivantes :
positionnement d'une broche centrale semblable à une tige (24) destinée à former le
trou longitudinal (h) suivant une relation de position prédéterminée par rapport à
une surface de formation de cavité d'une matrice de coulée (10),
positionnement d'une paire de broches de mandrin (12r, 14r4) destinée à former la
paire de trous transversaux de sorte qu'une face d'extrémité de chaque broche de mandrin
soit en contact avec une surface latérale de la broche centrale (24), et
chargement d'un métal fondu jusque dans les cavités de matrice (15) après que la broche
centrale (24) et la paire de broches de mandrin (12r, 14r4) ont été positionnées,
grâce à quoi la paire de broches de mandrin (12r, 14r4) est agencée de façon à agir
sur la broche centrale (24) de sorte qu'un déplacement radial de celle-ci soit restreint.
2. Procédé de coulage d'un tube (w), le tube comportant un trou longitudinal allongé
(h) et au moins un trou transversal (e1 à e4) communiquant avec le trou longitudinal
suivant une direction pratiquement normale à celui-ci, comprenant les étapes suivantes
:
positionnement d'une broche centrale semblable à une tige (124) destinée à former
le trou longitudinal (h) suivant une relation de position prédéterminée par rapport
à une surface de formation de cavité d'une matrice de coulée (110),
positionnement d'au moins une broche de mandrin (114r1 à 114r4) destinée à former
au moins un trou transversal de sorte qu'une face d'extrémité de la broche de mandrin
soit en contact avec une surface latérale de la broche centrale (124), et
chargement d'un métal fondu jusque dans la cavité de matrice (115),
grâce à quoi le métal fondu est chargé en direction de la broche de mandrin (114r4)
après que la broche centrale (124) et la broche de mandrin ont été positionnées.
3. Matrice de coulée destinée au coulage d'un tube (w), le tube comportant un trou longitudinal
allongé (h) et au moins une paire de trous transversaux (p, e4) communiquant avec
le trou longitudinal suivant une direction pratiquement normale à celui-ci, comprenant
:
une broche centrale (24) disposée dans une cavité de matrice (15) destinée à former
le trou longitudinal (h),
au moins une paire de broches de mandrin (12r, 14r4) faisant saillie jusque dans la
cavité de matrice (15) suivant une direction pratiquement normale à la broche centrale
(24) destinées à former la au moins une paire de trous transversaux, la position de
la broche centrale (24) étant restreinte suivant la direction radiale de celle-ci
au moyen de faces d'extrémité (12u, 14u) de la paire de broches de mandrin (12r, 14r4)
lorsque la matrice de coulée (10) est fermée, au moyen d'un agencement de la paire
de broches de mandrin (12r, 14r4) qui sont situées de façon à agir sur la broche centrale
(24) de sorte qu'un déplacement radial de celle-ci soit restreint.
4. Matrice de coulée selon la revendication 3, comprenant en outre une broche-poussoir
(44p, 44q) destinée à séparer un produit de coulée produit dans celle-ci d'une surface
de formation de la cavité (15), la broche-poussoir étant liée de façon rigide à une
broche de mandrin de la paire de broches de mandrin (12r).
5. Matrice de coulée destinée au coulage d'un tube (w), le tube comportant un trou longitudinal
allongé (h) et au moins un trou transversal (e1 à e4) communiquant avec le trou longitudinal
suivant une direction pratiquement normale à celui-ci, comprenant :
une broche centrale (124) disposée dans une cavité de matrice (115) destinée à former
le trou longitudinal (h),
au moins une broche de mandrin (114r1 à 114r4) faisant saillie jusque dans la cavité
de matrice (115) suivant une direction pratiquement normale à la broche centrale (124)
destinée à former le au moins un trou transversal,
un trou de coulée (R1) destiné à charger du métal fondu jusque dans la cavité de matrice
(115),
une face d'extrémité de la broche de mandrin (114r1 à 114r4) étant amenée jusqu'en
contact avec une surface latérale de la broche centrale (124) lorsque la matrice de
coulée est fermée, le trou de coulée (R2) et la broche de mandrin étant situés sur
des côtés opposés de la broche centrale (124).