Method for producing a box piston

Details Method for producing a box piston Method for producing a box piston

2001-11-16

2003-04-15

Elve, M. Alexandra (Department: 1725)

Metal founding

Process

Shaping liquid metal against a forming surface

C164S137000, C164S345000, C029S888040

Reexamination Certificate

active

06546993

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATIONS
Applicant claims priority under 35 U.S.C. §119 of German Application No. 199 22 809.4, filed on May 19, 1999. Applicant also claims priority under 35 U.S.C. §120 of PCT/DE00/00921, filed on Mar. 21, 2000. The international application under PCT article 21(2) was not published in English.
The invention relates to a method for producing a box piston.
Box piston are understood in this connection to be pistons which, below an about circular-cylindrical area receiving the piston rings, have a through-extending outer contour that highly deviates from the circular shape in that the hubs and the walls of the box are recessed toward the center axis of the piston, and that defined supporting sections of the shaft wall are still present only in the zone of the pressure and counter-pressure sides, such sections being determined by the piston diameter.
Such a piston is known from U.S. Pat. No. 5,058,489. Such a piston is normally produced by casting an aluminum alloy in a metal mold. The recess or high casting between the hub support and the ring band (compare
FIG. 2
of said patent) is produced in this connection by linearly displaceable core parts. Conditioned by the purely linear displacement of the core, the shaping of the recesses and thus also the possible weight reduction of the piston are subject to limitations.
Therefore, the invention is dealing with the problem of permitting in connection with box pistons with recesses between the ring band and the hub support, variable shaping of the recesses, and of producing in a simple manner defined features of the shape in the area of the wall of the box, if necessary.
Said problem is solved by the method according to the invention. Advantageous further developments are the object of further embodiments.
The axial direction is to be understood in this connection to be the direction of the longitudinal axis of the piston, and the radial direction is a direction extending perpendicular to the longitudinal axis.
Owing to the fact that the casting cores producing the recesses can be pivoted, it is possible to produce undercuts especially in the area behind the ring grooves without having to divide the cores as it was required until now for that purpose in connection with pistons.
The casting core producing the recess may, in this connection, form one piece with the window insert of the casting mold; the casting core may be connectable with the window insert; or the window insert and the casting core producing the recess are capable of pivoting independently of one another; or the window insert is displaceable only linearly. The window insert is to be understood as being the part of the mold that shapes the piston especially in the area of the outwardly pointing box wall and the adjacent hubs.
Furthermore, by suitably selecting the pivot point and the draw-in angle, it is made possible—if weight-reducing breakthroughs have to be produced in the walls of the box as well—to produce such breakthroughs without using spindle sleeves by producing the rounding radii at least in the upper outer area of the breakthroughs with pivoting window inserts as well.
As with linearly displaceable casting cores, for stripping the cast part without problems, provision has to be made for a draw-in gradient or draw-in angle depending on the pivot point of the casting core. As opposed to the known casting cores, the position of such angle varies, and its size may vary locally as well.


REFERENCES:
patent: 1803301 (1931-04-01), Fahlman
patent: 5058489 (1991-10-01), Iwaya
patent: 5285840 (1994-02-01), Hayashi et al.
patent: 5311918 (1994-05-01), Scott
patent: 5809962 (1998-09-01), Abbott et al.
patent: 5924472 (1999-07-01), Suzuki et al.
patent: 26 22 595 (1976-12-01), None
patent: 197 46 102 (1999-04-01), None
patent: 198 13 745 (1999-04-01), None
patent: 0 605 910 (1994-07-01), None

Affiliated with

Also associated with

Rating

Method for producing a box piston does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method for producing a box piston, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for producing a box piston will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3039605