U.S. patent application number 17/347931 was filed with the patent office on 2022-03-24 for plunger tip and sliding method.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. The applicant listed for this patent is TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Shuji SOTOZAKI.
Application Number | 20220088673 17/347931 |
Document ID | / |
Family ID | 1000005707167 |
Filed Date | 2022-03-24 |
United States Patent
Application |
20220088673 |
Kind Code |
A1 |
SOTOZAKI; Shuji |
March 24, 2022 |
PLUNGER TIP AND SLIDING METHOD
Abstract
A plunger tip slides along an inner surface of the plunger
sleeve and that injects a molten metal into a mold. The plunger tip
includes: a tip main body; a ring-shaped hard resin member that is
attached to an outer peripheral surface of the tip main body and
that is in contact with the inner surface of the plunger sleeve at
least during a hot period in which the plunger tip slides along the
inner surface of the plunger sleeve; and a silicone resin member
positioned between the tip main body and the ring-shaped hard resin
member, in which a radial thickness of the silicone resin member
during the hot period is thinner than a radial thickness of the
silicone resin member during a cold period in which the molten
metal is not supplied in the plunger sleeve.
Inventors: |
SOTOZAKI; Shuji;
(Okazaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOYOTA JIDOSHA KABUSHIKI KAISHA |
Toyota-shi |
|
JP |
|
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
|
Family ID: |
1000005707167 |
Appl. No.: |
17/347931 |
Filed: |
June 15, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22D 17/203
20130101 |
International
Class: |
B22D 17/20 20060101
B22D017/20 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2020 |
JP |
2020-156841 |
Claims
1. A plunger tip that slides along an inner surface of a plunger
sleeve and that injects a molten metal into a mold, the plunger tip
comprising: a tip main body; a ring-shaped hard resin member that
is attached to an outer peripheral surface of the tip main body and
that is in contact with the inner surface of the plunger sleeve at
least during a hot period in which the plunger tip slides along the
inner surface of the plunger sleeve; and a ring-shaped elastic
member positioned between the tip main body and the ring-shaped
hard resin member, wherein a radial thickness of the ring-shaped
elastic member during the hot period is thinner than a radial
thickness of the ring-shaped elastic member during a cold period in
which the molten metal is not supplied in the plunger sleeve.
2. The plunger tip according to claim 1, wherein the ring-shaped
elastic member is formed of a silicone resin.
3. The plunger tip according to claim 1, wherein the ring-shaped
elastic member is an elastic spring.
4. The plunger tip according to claim 1, wherein the ring-shaped
hard resin member is in contact with the inner surface of the
plunger sleeve both during the hot period and during the cold
period.
5. A sliding method in which a plunger tip is slid along an inner
surface of a plunger sleeve to inject molten metal into a mold, the
plunger tip comprising: a tip main body; a ring-shaped hard resin
member that is attached to an outer peripheral surface of the tip
main body and that is in contact with the inner surface of the
plunger sleeve at least during a hot period in which the plunger
tip slides along the inner surface of the plunger sleeve; and a
ring-shaped elastic member positioned between the tip main body and
the ring-shaped hard resin member, wherein a radial thickness of
the ring-shaped elastic member during the hot period is thinner
than a radial thickness of the ring-shaped elastic member during a
cold period in which the molten metal is not supplied in the
plunger sleeve.
6. The sliding method according to claim 5, wherein the ring-shaped
elastic member is formed of a silicone resin.
7. The sliding method according to claim 5, wherein the ring-shaped
elastic member is an elastic spring.
8. The sliding method according to claim 5, wherein the ring-shaped
hard resin member is in contact with the inner surface of the
plunger sleeve both during the hot period and during the cold
period.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Japanese Patent
Application No. 2020-156841 filed on Sep. 18, 2020, incorporated
herein by reference in its entirety.
BACKGROUND
1. Technical Field
[0002] The present disclosure relates to a plunger tip and a
sliding method.
2. Description of Related Art
[0003] A plunger tip used in a die casting machine slides in a
plunger sleeve. Thus, lubricity and sealing property are required
between the plunger tip and an inner surface of the plunger sleeve.
In Japanese Unexamined Patent Application Publication No.
2006-035308 (JP 2006-035308 A), a part of an outer peripheral side
surface of a tip main body is covered with a hard resin, and the
hard resin comes into contact with an inner surface of a plunger
sleeve and thus, lubricity and sealing property are provided
between the plunger tip and the inner surface of the plunger
sleeve.
SUMMARY
[0004] Although the hard resin used for the plunger tip is required
to have heat resistance, a hard resin having high heat resistance
has a large coefficient of thermal expansion in general. Thus, in
JP 2006-035308 A, when it is designed such that the hard resin is
in contact with the inner surface of the plunger sleeve in a state
in which the molten metal is supplied in the plunger sleeve (in the
present disclosure, referred to as "during a cold period" or a
"cold period"), the diameter of the hard resin is increased due to
thermal expansion when the plunger tip slides in the plunger sleeve
to inject the molten metal supplied in the plunger sleeve 200 into
the mold (in the present disclosure, referred to as "during a hot
period" or a "hot period"). Thus, the frictional resistance during
sliding becomes too large. In contrast, if the size of the diameter
of the hard resin is designed in consideration of the thermal
expansion of the hard resin during the hot period so that the
frictional resistance during sliding does not become too large,
there is a possibility that the sealing property of the hard resin
and the inner surface of the plunger sleeve during the hot period
cannot be sufficiently obtained when the thermal expansion of the
hard resin is not as designed, and the like.
[0005] The present disclosure has been made to solve such a
problem, and the object of the present disclosure is to provide a
plunger tip and a sliding method that can further reduce a
frictional resistance during sliding while ensuring a sealing
property during the hot period.
[0006] A plunger tip slides along an inner surface of the plunger
sleeve and that injects a molten metal into a mold. The plunger tip
includes: a tip main body; a ring-shaped hard resin member that is
attached to an outer peripheral surface of the tip main body and
that is in contact with the inner surface of the plunger sleeve at
least during a hot period in which the plunger tip slides along the
inner surface of the plunger sleeve; and a ring-shaped elastic
member positioned between the tip main body and the ring-shaped
hard resin member, in which a radial thickness of the ring-shaped
elastic member during the hot period is thinner than a radial
thickness of the ring-shaped elastic member during a cold period in
which the molten metal is not supplied in the plunger sleeve.
[0007] In a sliding method according to the present disclosure, a
plunger tip slides along an inner surface of a plunger sleeve and
injects a molten metal into a mold. The plunger tip includes: a tip
main body; a ring-shaped hard resin member that is attached to an
outer peripheral surface of the tip main body and that is in
contact with the inner surface of the plunger sleeve at least
during a hot period in which the plunger tip slides along the inner
surface of the plunger sleeve; and a ring-shaped elastic member
positioned between the tip main body and the silicone resin member,
in which a radial thickness of the ring-shaped elastic member
during the hot period is thinner than a radial thickness of the
ring-shaped elastic member during a cold period in which the molten
metal is not supplied in the plunger sleeve.
[0008] In the plunger tip according to the present disclosure,
since the ring-shaped elastic member becomes thinner during the hot
period than during the cold period, even when the diameter of the
ring-shaped hard resin member is increased due to thermal
expansion, it is possible to suppress the frictional resistance
between the inner surface of the plunger sleeve and the ring-shaped
hard resin member from being increased. Further, since the
ring-shaped hard resin member comes into contact with the inner
surface of the plunger sleeve at least during the hot period, it is
possible to secure the sealing property during the hot period. This
makes it possible to provide the plunger tip that can further
reduce the frictional resistance during sliding while ensuring the
sealing property during the hot period.
[0009] In the sliding method according to the present disclosure,
since the ring-shaped elastic member becomes thinner during the hot
period than during the cold period, even when the diameter of the
ring-shaped hard resin member is increased due to thermal
expansion, it is possible to suppress the frictional resistance
between the inner surface of the plunger sleeve and the ring-shaped
hard resin member from being increased. Further, since the
ring-shaped hard resin member comes into contact with the inner
surface of the plunger sleeve at least during the hot period, it is
possible to secure the sealing property during the hot period. This
makes it possible to provide the sliding method that can further
reduce the frictional resistance during sliding while ensuring the
sealing property during the hot period.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Features, advantages, and technical and industrial
significance of exemplary embodiments of the disclosure will be
described below with reference to the accompanying drawings, in
which like signs denote like elements, and wherein:
[0011] FIG. 1 is a partial cross-sectional view showing a plunger
tip and a plunger sleeve according to a first embodiment of the
present disclosure; and
[0012] FIG. 2 is a partial cross-sectional view showing a plunger
tip and a plunger sleeve according to a second embodiment of the
present disclosure.
DETAILED DESCRIPTION OF EMBODIMENTS
First Embodiment
[0013] Hereinafter, a first embodiment of the present disclosure
will be described with reference to the drawings. However, the
disclosure is not limited to the following first embodiment. The
following description and drawings are simplified as appropriate
for the sake of clarity.
[0014] FIG. 1 is a partial cross-sectional view showing a plunger
tip 100 and a plunger sleeve 200 according to the first embodiment
of the present disclosure. On the left side of FIG. 1, the plunger
tip 100 and the plunger sleeve 200 in a state in which a molten
metal is not supplied in the plunger sleeve 200 (hereinafter,
referred to as "during a cold period" or "a cold period" in the
present specification) is shown. On the right side of FIG. 1, the
plunger tip 100 and the plunger sleeve 200 in a state in which the
molten metal is supplied in the plunger sleeve 200 (hereinafter,
referred to as "during a hot period" or "a hot period" in the
present specification) is shown. The plunger tip 100 slides along
an inner surface of the plunger sleeve 200 having a cylindrical
shape, and injects the molten metal supplied in the plunger sleeve
200 into a mold. As shown in FIG. 1, the plunger tip 100 includes a
tip main body 101, a ring-shaped hard resin member 102
(hereinafter, simply referred to as a "hard resin member 102"), and
a ring-shaped silicone resin member 103 (hereinafter, simply
referred to as a "resin member 103") serving as a ring-shaped
elastic member.
[0015] The tip main body 101 has a cylindrical shape, and a cooling
device can be provided inside the cylindrical shape. Here, the
cooling device is, for example, a cooling pipe or the like that
serves as a flow path for a refrigerant. When the cooling device is
not required, the tip main body 101 may have a columnar shape
instead of a cylindrical shape. The tip main body 101 is made of
heat-resistant tool steel or the like. Further, the tip main body
101 may be formed of a copper alloy such as beryllium copper.
[0016] Further, in at least a part of the outer peripheral surface,
the tip main body 101 has a groove portion 101A extending along a
circumferential direction in which the hard resin member 102 and
the silicone resin member 103 can be disposed. The depth of the
groove portion 101A is determined by the thickness of the hard
resin member 102 and the thickness of the silicone resin member 103
disposed in the groove portion 101A. Specifically, the silicone
resin member 103 and the hard resin member 102 are disposed in this
order in the groove portion 101A toward an outer radial side of the
tip main body 101. The groove portion 101A has a depth in which the
hard resin member 102 can come into contact with the inner surface
of the plunger sleeve 200, at least during the hot period. As a
result, the sealing property between the inner surface of the
plunger sleeve 200 and the hard resin member 102 during the hot
period can be ensured. Further, the depth of the groove portion
101A may be a depth in which the hard resin member 102 comes into
contact with the inner surface of the plunger sleeve 200 during the
cold period. As a result, the sealing property between the inner
surface of the plunger sleeve 200 and the hard resin member 102
during the cold period can be more surely ensured. Specifically,
the sealing property can be ensured until the thermal expansion of
the hard resin member 102 is completed (in the initial stage of the
hot period). Here, "the thermal expansion of the hard resin member
102 is completed" means that the temperature of the hard resin
member 102 and the ambient temperature become substantially
constant, and the amount of thermal expansion of the hard resin
member 102 becomes substantially constant.
[0017] Further, the diameter of a part of the tip main body 101
excluding the groove portion 101A is slightly smaller than the
inner diameter of the plunger sleeve 200. In casting using a die
casting machine, the plunger tip 100 and the plunger sleeve 200 are
thermally expanded by the heat of the molten metal or the like.
Therefore, the diameter of the tip main body 101 is formed to be
slightly smaller than the inner diameter of the plunger sleeve 200
so that the thermal expansion of the tip main body 101 during the
hot period can be allowed. In other words, the diameter of the tip
main body 101 is such that a minute gap is formed between the outer
surface of the tip main body 101 and the inner surface of the
plunger sleeve 200 in a state in which the plunger sleeve 200 and
the tip main body 101 are thermally expanded. This makes it
possible to prevent frictional resistance from being generated
between the inner surface of the plunger sleeve 200 and the outer
surface of the plunger tip 100 when sliding the plunger tip 100
inside the plunger sleeve 200.
[0018] The hard resin member 102 is a ring-shaped member formed of
a hard resin having a high heat resistance. Further, the hard resin
member 102 is attached to the inside of the groove portion 101A of
the tip main body 101 and on the outer radial side of the tip main
body 101 of the silicone resin member 103 attached to the groove
portion 101A.
[0019] Further, the hard resin member 102 has a radial thickness
that allows contact with the inner surface of the plunger sleeve
200 at least during the hot period in which the plunger tip 100
slides along the inner surface of the plunger sleeve 200.
[0020] Specifically, during the cold period, that is, in the state
in which the silicone resin member 103 described below is not
compressed, the hard resin member 102 may have a radial thickness
so as to provide a slight gap between the inner surface of the
plunger sleeve 200 and the hard resin member 102. The slight gap
has a size in which the amount of thermal expansion of the hard
resin member 102 during the hot period and the amount of
compression of the silicone resin member 103 described later is
taken into consideration. More specifically, the slight gap has a
size in which it is possible to prevent the inner surface of the
plunger sleeve 200 and the hard resin member 102 from coming into
contact and prevent an excessive frictional resistance from being
generated when the plunger tip 100 slides along the inner surface
of the plunger sleeve 200, due to the hard resin member 102 being
thermally expanded by the heat of the molten metal during the hot
period and the silicone resin member 103 being compressed by the
thermal expansion of the hard resin member 102. As a result, the
sealing property during the hot period is ensured, and the
frictional resistance between the inner surface of the plunger
sleeve 200 and the hard resin member 102 when sliding the plunger
tip 100 can be prevented from becoming excessively large.
[0021] Alternatively, during the cold period, in the state in which
the silicone resin member 103 described below is not compressed,
the hard resin member 102 may have a radial thickness in which the
inner surface of the plunger sleeve 200 and the hard resin member
102 come into contact. In this case, it is possible to prevent an
excessive frictional resistance from being generated between the
inner surface of the plunger sleeve 200 and the hard resin member
102, due to the hard resin member 102 being thermally expanded and
the silicone resin member 103 being compressed by the thermal
expansion of the hard resin member 102, during the hot period.
Further, since the inner surface of the plunger sleeve 200 and the
hard resin member 102 are in contact during the cold period, the
sealing property can be ensured until the thermal expansion of the
hard resin member 102 is completed (the initial stage of the hot
period).
[0022] The silicone resin member 103 is a ring-shaped member formed
of a heat-resistant silicone resin. Further, the silicone resin
member 103 is attached to the inside of the groove portion 101A of
the tip main body 101 and on the inner radial side of the tip main
body 101 of the hard resin member 102 attached to the groove
portion 101A. That is, the silicone resin member 103 is positioned
between the tip main body 101 and the hard resin member 102.
Further, the silicone resin member 103 has, for example, a static
shear modulus of 0.2 MPa or more and 1.0 MPa or less. Then,
although the silicone resin member 103 slightly thermally expands
during the hot period, the silicone resin member 103 is actually
compressed by being pushed by the thermally expanded hard resin
member 102. In other words, the radial thickness of the silicone
resin member 103 during the hot period is thinner than the radial
thickness of the silicone resin member 103 during the cold period.
Further, during the cold period, the silicone resin member 103 is
not substantially compressed.
[0023] Next, a sliding method according to the first embodiment in
which a plunger tip 100 is slid along the inner surface of the
plunger sleeve 200 to inject a molten metal into a mold will be
described.
[0024] First, as shown on the left side of FIG. 1, the silicone
resin member 103 is not compressed during the cold period, and the
hard resin member 102 is in contact with the inner surface of the
plunger sleeve 200.
[0025] Next, as shown on the right side of FIG. 1, the molten metal
is supplied in the plunger sleeve 200, the molten metal causes the
plunger tip 100 and the plunger sleeve 200 to thermally expand
slightly and the hard resin member 102 to be thermally expanded
significantly, and the silicone resin member 103 is compressed by
the thermally expanded hard resin member 102. That is, the radial
thickness of the silicone resin member 103 during the hot period is
thinner than the radial thickness of the silicone resin member 103
during the cold period.
[0026] Then, the plunger tip 100 is slid along the inner surface of
the plunger sleeve 200 to inject the molten metal supplied in the
plunger sleeve 200 into the mold. At this time, while the hard
resin member 102 is thermally expanded, the silicone resin member
103 is compressed by the amount of thermal expansion of the hard
resin member 102. Thus, the frictional resistance during sliding
does not become excessively large. Further, since the inner surface
of the plunger sleeve 200 and the hard resin member 102 are already
in contact during the cold period, the sealing property can be
ensured until the thermal expansion of the hard resin member 102 is
completed (the initial stage of the hot period).
[0027] In the plunger tip 100 and the sliding method according to
the first embodiment described above, since the silicone resin
member 103 becomes thinner during the hot period than during the
cold period, even when the diameter of the hard resin member 102 is
increased due to thermal expansion, it is possible to suppress the
frictional resistance between the inner surface of the plunger
sleeve 200 and the hard resin member 102 during sliding of the
plunger tip 100 from being increased. Further, since the hard resin
member 102 comes into contact with the inner surface of the plunger
sleeve 200 at least during the hot period, it is possible to secure
the sealing property during the hot period. This makes it possible
to provide the plunger tip 100 and the sliding method that can
further reduce the frictional resistance during sliding while
ensuring the sealing property during the hot period.
Second Embodiment
[0028] Next, a plunger tip 100A according to a second embodiment of
the present disclosure will be described with reference to FIG. 2.
The following description and drawings are simplified as
appropriate for the sake of clarity.
[0029] As shown in FIG. 2, the plunger tip 100A according to the
second embodiment is different from the plunger tip 100 according
to the first embodiment in that an elastic spring 104 is provided
instead of the silicone resin member 103 as the ring-shaped elastic
member. Thus, in the plunger tip 100A according to the second
embodiment, the same components as those of the plunger tip 100
according to the first embodiment are indicated with the same
reference numerals, and the description thereof will be
omitted.
[0030] The elastic spring 104 is a ring-shaped leaf spring, and the
cross-sectional shape of the ring in the radial direction is
substantially U-shaped. Further, the elastic spring 104 is attached
to the inside of the groove portion 101A of the tip main body 101
and on the inner radial side of the tip main body 101 of the hard
resin member 102 attached to the groove portion 101A. That is, the
elastic spring 104 is positioned between the tip main body 101 and
the hard resin member 102. Further, during the hot period, the
elastic spring 104 contracts by being pushed by the thermally
expanded hard resin member 102. In other words, the radial
thickness of the elastic spring 104 during the hot period is
thinner than the radial thickness of the elastic spring 104 during
the cold period. Also, during the cold period, the elastic spring
104 is not substantially compressed.
[0031] Next, a sliding method according to the second embodiment in
which the plunger tip 100 is slid along the inner surface of the
plunger sleeve 200 to inject the molten metal into the mold will be
described.
[0032] First, as shown on the left side of FIG. 2, the elastic
spring 104 is not compressed during the cold period, and the hard
resin member 102 is in contact with the inner surface of the
plunger sleeve 200.
[0033] Next, as shown on the right side of FIG. 2, the molten metal
is supplied in the plunger sleeve 200, the molten metal causes the
plunger tip 100 and the plunger sleeve 200 to thermally expand
slightly and the hard resin member 102 to be thermally expanded
significantly, and the elastic spring 104 pressed by the thermally
expanded hard resin member 102 is shrunk. That is, the radial
thickness of the elastic spring 104 during the hot period is
thinner than the radial thickness of the elastic spring 104 during
the cold period.
[0034] Then, the plunger tip 100 is slid along the inner surface of
the plunger sleeve 200 to inject the molten metal supplied in the
plunger sleeve 200 into the mold. At this time, while the hard
resin member 102 is thermally expanded, the elastic spring is
shrunk by the amount of thermal expansion of the hard resin member
102. Thus, the frictional resistance during sliding does not become
excessively large. Further, since the inner surface of the plunger
sleeve 200 and the hard resin member 102 are already in contact
during the cold period, the sealing property can be ensured until
the thermal expansion of the hard resin member 102 is completed
(the initial stage of the hot period).
[0035] In the plunger tip 100 and the sliding method according to
the second embodiment described above, since the elastic spring 104
becomes thinner during the hot period than during the cold period,
even when the diameter of the hard resin member 102 is increased
due to thermal expansion, it is possible to suppress the frictional
resistance between the inner surface of the plunger sleeve 200 and
the hard resin member 102 during sliding of the plunger tip 100
from being increased. Further, since the hard resin member 102
comes into contact with the inner surface of the plunger sleeve 200
at least during the hot period, it is possible to secure the
sealing property during the hot period. This makes it possible to
provide the plunger tip 100A and the sliding method that can
further reduce the frictional resistance during sliding while
ensuring the sealing property during the hot period.
[0036] The present disclosure is not limited to the above
embodiments, and can be appropriately modified without departing
from the spirit thereof.
* * * * *