Brakes – Wheel – Axially movable brake element or housing therefor
Reexamination Certificate
1998-04-14
2001-02-27
Oberleitner, Robert J. (Department: 3613)
Brakes
Wheel
Axially movable brake element or housing therefor
C188S2640AA
Reexamination Certificate
active
06193023
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates to a method of cooling a brake rotor and specifically for varying the angles of the vents in a rotor friction section to change the air flow through the vents for cooling the rotor.
Wheeled vehicles are typically slowed and stopped with a braking system that generates frictional forces. Many braking systems include a rotor attached to one or more of the vehicle wheels for rotation therewith, and a caliper assembly secured to a non-rotating component of the vehicle, such as the vehicle frame. The rotor includes an annular peripheral friction section having friction surfaces disposed on opposite sides. The caliper assembly includes a pair of brake pads disposed adjacent the rotor friction surfaces, and a moveable piston operatively connected to one or more of the brake pads. When the driver brakes the vehicle, hydraulic or pneumatic forces move the piston which clamps the pads against the friction surfaces of the rotating rotor. As the brake pads press against the moving friction surfaces, frictional forces are created which oppose the rotation of the wheels and slow the vehicle. The friction converts the vehicle's kinetic energy into large quantities of heat, much of which is absorbed by the friction surfaces and conducted throughout the rotor.
It is important to dissipate the heat and cool the rotor. If the rotor is not adequately cooled, the heat generated during braking can build up in the rotor reducing braking performance by creating longer stopping distances, shorten the life of the rotor, or even cause brake failure. The rotor also helps to keep the brake pads cool by absorbing the braking heat and moving it away from the pads. However, the rotor can only absorb a finite amount of heat and if it is not cooled effectively it will absorb less and less heat, causing the brake pads to overheat and thus reducing braking performance and shortening the life of the brake pads.
Rotors are commonly cooled using moving air which absorbs the heat from the rotor and carries it away. It is known to “ventilate” the rotors by forming passages or vents between the friction surfaces to allow cooling air to pass through. These ventilated rotors typically include friction surfaces formed on a pair of annular friction plates joined together by spacers or posts in a mutually parallel, spaced apart relationship to form spaces or vents therebetween. The vents are open at the radially inner and outer edges of the friction plates to form air passages between the friction plates. As the vented rotor turns, air moves through the vents between the friction surfaces and absorbs heat from the friction plates to cool the rotor.
The cooling effectiveness of the vents is proportional to the quantity of air moved through them. The more air the vents move past the rotor surfaces, the more heat that is dissipated and the greater the cooling effects. Therefore, it is desirable to move as much air as possible through the vents. The shapes, spacing and orientation of the posts determine the amount of air which passes through the vents. It is desirable to provide the optimum shape, spacing and orientation of posts to maximize the airflow through the vents.
SUMMARY OF THE INVENTION
The invention is directed to a ventilated rotor having annular friction plates joined together by spacers or posts in a mutually parallel, spaced apart relationship to form spaces or vents therebetween. The vents are open at the radially inner and outer edges of the friction plates to allow air to pass between the friction plates and cool the rotor as it turns. The posts include a plurality of first posts having an elongated cross sectional shape, and a plurality of second posts having a circular cross sectional shape. The posts are arranged in a plurality of circumferentially extending rows and radially extending columns to form vents for cooling the rotor.
One embodiment of the rotor includes posts arranged in a plurality of radially spaced first and second rows. The first rows are interspersed with the second rows in alternating fashion. The posts of the first rows are spaced to form radially extending first columns and the posts of the second rows are spaced to from radially extending second columns. The first and second columns are alternately disposed along the circumferential direction of the friction plates.
A second embodiment of the rotor includes posts being arranged in a plurality of radially spaced rows such that the centers of the posts in any particular row are all spaced the same distance from the center of the rotor. The posts are also arranged in a plurality of circumferentially spaced columns such that radially extending vents are formed between the columns.
A third embodiment of the rotor includes a plurality of first posts extending between the friction plates and having elongated cross sectional shapes having centers and extending along axes. The first posts are arranged in a first row such that the centers of the posts are all spaced the same distance from the center of the rotor. The rotor also includes a plurality of second posts extending between the friction plates and having circular cross sectional shapes with centers. The second posts are arranged in a plurality of second rows such that the centers of the posts in a particular second row are all spaced the same distance from the center of the rotor. The plurality of second rows are disposed radially inwardly from the first row forming radially extending columns such that the columns include a single post from the first row and a pair of second posts from each of the second rows.
A fourth embodiment of the rotor includes a plurality of first posts extending between the friction plates and having elongated cross sectional shapes having centers and extending along axes. The first posts are arranged in a plurality of first rows such that the centers of the posts in a particular first row are all spaced the same distance from the center of the rotor. The rotor further includes a plurality of second posts having circular cross sectional shapes with centers. The second posts are arranged in a plurality of second rows such that the centers of the posts in a particular second row are all spaced the same distance from the center of the rotor. The plurality of first and second rows are interspersed in alternating fashion to form radially extending columns such that the columns include a single first post from each of the first rows and a pair of second posts from each of the second rows.
A fifth embodiment of said brake rotor including a central hat section, a peripheral annular friction section having a pair of annular spaced apart friction plates, and a plurality of posts extending between said friction plates. The posts have V-shaped cross sectional shapes with an open end and a closed end. The posts are arranged in a row extending around at least a portion of the circumference of said friction plates.
A sixth embodiment of said brake rotor including a central hat section, a peripheral annular friction section having a pair of annular spaced apart friction plates, and a plurality of posts extending between said friction plates. The posts have S-shaped cross sectional. The posts are arranged in a row extending around at least a portion of the circumference of said friction plates.
REFERENCES:
patent: 2197232 (1940-04-01), Wood
patent: 3730304 (1973-05-01), Buyze
patent: 4250979 (1981-02-01), Kawaguichi
patent: 5188203 (1993-02-01), Winter
patent: 5544726 (1996-08-01), Topouzian et al.
Hayes Lemmerz International Inc.
Marshall & Melhorn LLC
Oberleitner Robert J.
Rodriguez Pamela J.
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