Power plants – Pressure fluid source and motor – Pulsator
Reexamination Certificate
2002-08-23
2004-11-16
Look, Edward K. (Department: 3745)
Power plants
Pressure fluid source and motor
Pulsator
C092S169200, C029S888020
Reexamination Certificate
active
06817178
ABSTRACT:
This application is based on and claims priority under 35 U.S.C. §119 with respect to Japanese Patent Application No. 2001-254395 filed on Aug. 24, 2002, the entire content of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention generally relates to a master cylinder. More particularly, the present invention pertains to a master cylinder body and a die for molding the master cylinder body.
BACKGROUND OF THE INVENTION
Master cylinders are applied as a part of a power transmission means in brake system of automobiles. As shown in
FIG. 10
, a master cylinder
60
includes a master cylinder body
61
, a piston
62
, and a reservoir
63
. The master cylinder body
61
includes a hollow construction inside thereof and the brake fluid filled in the reservoir
63
is charged in the hollow space of the master cylinder body
61
via pipes (not shown).
By depressing a brake pedal of the automobile, the depression force is transmitted to the piston
62
slidably inserted into and supported by the master cylinder body
61
as shown in FIG.
10
. The piston
62
is slid leftward of
FIG. 10
, the connection between the master cylinder body
61
and the reservoir
63
is interrupted, and the hydraulic pressure is generated in the brake fluid charged in the master cylinder body
61
. The hydraulic pressure is transmitted to a brake mechanism (not shown) via outlet ports
64
,
65
projected from an external peripheral side surface of the master cylinder body
61
to operate the brakes.
The master cylinder body
61
having the foregoing construction is manufactured by the aluminum die casting. That is, the melt of the aluminum alloy is poured into a die having a predetermined configuration for molding the master cylinder body
61
via a sprue (i.e., a tip end surface
61
a
side of the master cylinder body
61
). By cooling down the melt poured into the die, the master cylinder body
61
is formed. In this regard, the melt may be partially cooled down to be solidified before being charged into the outlet ports
64
,
65
because the volume of the outlet ports
64
,
65
is large. Thus, the melt is hard to be flowed and the casting cavity is generated. The generation of the casting cavity not only deforms the configuration of the master cylinder body
61
but also deteriorates the rigidity of the master cylinder body
61
.
In order to restrain the generation of the casting cavity, as shown in
FIG. 10
, a rib
66
is provided from the outlet port
64
to the tip end surface
61
a
of the master cylinder
61
on an imaginary line perpendicularly crossing the central axial lines of the outlet ports
64
,
65
. A space for molding the rib
66
is formed in the die to improve the flow of the melt. Thus, the generation of the casting cavity in the outlet ports
64
,
65
can be prevented.
The rib
66
is formed from the outlet port
65
to the tip end surface
61
a
of the master cylinder body
61
on the imaginary line crossing the central axial lines of the outlet ports
64
,
65
. When the melt is introduced from the sprue (i.e., the tip end surface
61
a
side), the melt directly collides with projections of the die for molding the outlet ports
64
,
65
, thus the abrasion of the portion of the die for molding the outlet ports
64
,
65
were notable. The abrasion of the portion for forming the outlet ports
64
,
65
is the drawback for improving the life duration of the die.
A need thus exists for a master cylinder body and a die for molding the master cylinder body which improves the life duration of a die of the master cylinder body which is unlikely worn out by the flow of the melt.
SUMMARY OF THE INVENTION
In light of the foregoing, the present invention provides a master cylinder body which includes a first output port for outputting hydraulic pressure, a second output port for outputting the hydraulic pressure, and a rib formed between the first and the second port portions towards a tip end portion of the master cylinder body for improving a flow of melt. The rib is formed along a position deviated from a line connecting central axial lines of the first and the second output port portions.
According to another aspect of the present invention, a die of a master cylinder body which includes a first and a second output ports for outputting hydraulic pressure and a rib formed between the first and the second output port portions for improving a flow of melt towards a tip end portion includes a first port molding recess portion, a second port molding recess portion, a first projection formed on the first port molding recess portion, a second projection formed on the second port molding recess portion, and a rib molding recess portion. The rib molding recess portion is formed on a position deviated from a line connecting a central axial lines of the first and the second projections formed on the first and the second port molding recess portions.
REFERENCES:
patent: 4122596 (1978-10-01), Fields
patent: 4276994 (1981-07-01), Spalding
patent: 4687042 (1987-08-01), Young
patent: 4823553 (1989-04-01), Reynolds
patent: 5331813 (1994-07-01), Heibel et al.
patent: 2001-30892 (2001-02-01), None
Enomoto Naoyasu
Sato Isao
Aisin Seiki Kabushiki Kaisha
Kershteyn Igor
Look Edward K.
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