Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – Shaping against forming surface
Patent
1991-06-20
1993-03-02
Heitbrink, Jill L.
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
Shaping against forming surface
29898049, 2989805, B29C 4500
Patent
active
051907135
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a process for the production of a roller bearing cage or a roller bearing needle ring with molded-on spring elements, especially of a grip roller overrunning clutch and to a roller bearing cage thus produced.
From German Aulegesschrift 286 843 a cage is known for guiding the grip rollers of a grip roller overrunning clutch, which consists of two guide rings (shoulders), placed on both sides of the grip rollers, connected to one another by several axis-parallel webs. On each web a ramp is molded on one side and on the other side a leaf spring for prestressing the grip rollers. The cage with the leaf springs is injection molded from elastic plastic in one piece. These and other cages on the market are produced with injection molds or casting molds, in which the sprues are provided in the area of the guide rings or shoulders or in the transition area between the shoulders and the webs. This type of gate or position of the sprues leads to a laminar flow of the polymer material used, which does not make possible a specific orientation of the molecule chains and of the perhaps embedded reinforcement fibers in the area of the spring elements.
With this invention the object is to be achieved of indicating a process for the production of a roller bearing cage with molded-on spring elements and to configure a roller bearing cage thus produced so that spring tension of the spring elements is increased in comparison with known embodiments, especially the spring rigidity of the spring element or spring elements that are molded on is substantially improved.
This object is achieved by the process steps or features indicated below which include:
The common use of the process steps
molding of the spring elements on the web by a large-volume spring base, and
each spring base is used directly or the adjacent web or the area between the spring base and the adjacent web is used as gate and further
the flow channel of the spring base is dimensioned greater in volume than the flow channel of the spring element or elements branching off on the spring base, and finally
a self- or internally reinforcing plastic or a polymer blend or a compound of several plastics with liquid crystal portions is used as polymer material which allows the spring element or elements to polymerize in the flow direction as molecules with specific orientation.
The following advantages, in comparison with the previously known processes for the production of such roller bearing cages or roller bearing needle rings are:
The flash formation at the separation sites of the mold is considerably reduced, since polymer material used because of the arrangement and design of the gates promotes the orientation molecules in the flow direction, at the same time makes possible the use of polymer materials with low viscosity and preferably also the casting with lower specific pressures. Moreover, with the polymer materials used the polymerization process is completed comparatively quickly. The cold flow tendency or creep effect of these polymer materials with the use of the process according to the invention is unusually small, which also leads to improved spring characteristics.
It is to be expected that with the roller bearing cages produced according to the process of the invention the spring characteristic values of the molded-on spring elements are substantially improved, especially at least a doubling of the spring rigidity as a function of the test temperature in comparison with known spring elements is to be expected.
Other advantageous details of the invention are claimed in the subclaims and are described in greater detail in the following description by the embodiments illustrated in the drawing:
There are shown in:
FIG. 1, a top view of a development of a roller bearing cage with two spring elements per web;
FIG. 2, a view according to section A--A of FIG. 1, but not in the development but as a segment of a roller bearing cage,
FIG. 3, a top view of a development of a roller bearing cage with one spring element per web and laterally
REFERENCES:
patent: 3260333 (1966-07-01), Bensen et al.
patent: 3537554 (1970-11-01), Elmore
patent: 3795382 (1974-03-01), Gruber et al.
patent: 3863742 (1975-02-01), Elmore et al.
patent: 3937312 (1976-02-01), Gehrke
patent: 3993176 (1976-11-01), Marola et al.
patent: 4588314 (1986-05-01), Anscher
patent: 4654181 (1987-03-01), Brandenstein et al.
patent: 4668209 (1987-05-01), Kyoosei et al.
patent: 4747900 (1988-05-01), Angus
patent: 4915201 (1990-04-01), Stark et al.
"Selbstverstaerkende Polymere", Technische Rundschau, 18/89; Von Dietrich Fleischer und Guenther Kirsch, Seiten 21-31.
LandOfFree
Process for the production of a roller bearing cage with molded- does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the production of a roller bearing cage with molded-, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the production of a roller bearing cage with molded- will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-125169