Brakes – Wheel – Transversely movable
Reexamination Certificate
1999-11-24
2001-12-11
Oberleitner, Robert J. (Department: 3613)
Brakes
Wheel
Transversely movable
C188S259000
Reexamination Certificate
active
06328140
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a double wrap brake band apparatus used in an automatic transmission.
2. Related Background Art
A conventional double wrap brake band apparatus generally used in an automatic transmission will firstly be described.
FIG. 9
is a front view showing a condition that a substantially C-shaped double wrap brake band apparatus
510
is disposed around an outer periphery of an inner race (drum)
528
.
The double wrap brake band apparatus
510
comprises an intermediate band
512
and outer bands
514
,
516
. A connection member
536
is secured to one circumferential ends of the outer bands
514
,
516
by rivets, and an anchor bracket
531
having a hole
530
for receiving an anchor pin
532
is secured to the other circumferential ends (free ends) of the outer bands
514
,
516
by rivets.
On the other hand, the intermediate band
512
has one end (free end) received circumferentially between the outer bands
514
,
516
and the other end spaced apart from the one end in a circumferential direction and secured to the connection member
536
by rivets in a condition that the other end is protruded circumferentially between the outer bands
514
,
516
.
Further, the intermediate band
512
is provided at its outer peripheral surface with an apply bracket
526
having a receiving surface
546
a
for receiving an urging force from an urging piston.
The double wrap brake band apparatus
510
having the above-mentioned construction is secured via the anchor pin
532
secured to the anchor bracket
531
and receives torque when the brake band apparatus tightens the inner race
528
by urging (downwardly in
FIG. 9
) the apply bracket
526
by means of an urging piston
520
having a base portion
522
and an urging rod
524
.
FIG. 10
is a side view of the arrangement shown in FIG.
9
. Friction materials
534
are adhered to inner peripheral surfaces of the intermediate band
512
and the outer bands
514
,
516
. As shown, from a released condition of the inner race
528
, when the urging piston
520
is protruded or extended to urge an acting portion
546
of the apply bracket
526
downwardly, a force is transmitted to lower portions of the intermediate band
512
and the outer bands
514
,
516
. As a result, although the anchor bracket
531
tries to shift downwardly through the connection member
536
, since the movement of the anchor bracket is prevented by the anchor pin
532
, the intermediate band
512
and the outer bands
514
,
516
tighten an outer peripheral surface of the inner race
528
, thereby braking rotation of the inner race
528
.
By the way, when the double wrap brake band apparatus
510
is used in the automatic transmission, a torque capacity to be allotted is varied with a using condition. For example, at a first speed in an R range or a D range, although high torque is allotted, torque to be allotted during transmitting may be about {fraction (1/10)} of such high torque. However, in the transmitting, although the inner race
528
must be held for a very short time, since the double wrap brake band apparatus
510
has windings greater than a single winding brake band apparatus (not shown), the shifting amount of the urging piston
520
is increased accordingly, with the result that there arises a problem that it takes a relatively long time for completion of the operation of the double wrap brake band apparatus.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a double wrap brake band apparatus used as a brake of an automatic transmission, in which an inner race can be held for a very short time by operating only a band portion corresponding to about one winding during transmitting.
To achieve the above object, in a double wrap brake band apparatus according to the present invention, second anchor means or apply means are provided in the vicinity of a connecting portion between an intermediate band and outer bands.
More specifically, the second anchor means is constituted by an anchor bracket secured to one of the bands and an anchor pin for supporting the anchor bracket, and the apply means is constituted by an apply bracket secured to one of the bands and a piston for urging the apply bracket.
When a second apply bracket is provided, the pistons for urging the first and second apply brackets are operated independently. To save a space, the pistons are assembled as a dual construction.
When a single piston is provided, respective urging rods or respective anchor brackets are connected to the piston via elastic means.
REFERENCES:
patent: 4602706 (1986-07-01), Blinks et al.
patent: 4757880 (1988-07-01), Grzesiak
patent: 5012905 (1991-05-01), Tanaka
patent: 5083642 (1992-01-01), Stefanutti et al.
patent: 5476160 (1995-12-01), Fenoglio et al.
patent: 37-6811 (1962-04-01), None
Miles & Stockbridge P.C.
NSK-Warner K.K.
Oberleitner Robert J.
Sy Mariano
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