Brakes – Wheel – Axially movable brake element or housing therefor
Reexamination Certificate
1999-08-27
2001-05-29
Lorence, Richard M. (Department: 3681)
Brakes
Wheel
Axially movable brake element or housing therefor
C192S070120, C192S113340, C188S26400E
Reexamination Certificate
active
06237727
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wet type multi-plate friction engaging apparatus, and more particularly, it relates to a wet type multi-plate friction engaging apparatus mainly used as a brake of a transmission, in which friction materials are adhered to only outer tooth plates or outer tooth plates and a flange.
2. Related Background Art
FIG. 2
is an axial sectional view of a conventional wet type multi-plate friction engaging apparatus
70
. A drum
61
is secured to a transmission case (not shown), a retainer
59
is disposed on an inner periphery of the drum
61
, and outer tooth plates
51
are incorporated in the retainer. Further, inner tooth plates
54
are attached to an outer peripheral surface of a hub
55
rotated in a direction shown by the arrow A and are interposed between the respective outer tooth plates
51
. The outer tooth plates
51
and the inner tooth plates
54
are rotated relative to each other. A piston
52
is mounted near a closed end of the drum
61
and is operated by oil pressure supplied to an oil chamber defined between the piston and the side wall of the drum
61
. A flange
64
is secured to an open end portion of the drum
61
by a snap ring
63
. For friction engagement, the piston
52
is axially shifted to the right in
FIG. 2
to urge the outer tooth plates
51
.
In order to lubricate the frictional engagement surfaces between the outer tooth plates and the inner tooth plates from an axially central side, the hub
55
is provided with lubricating oil through holes
56
extending radially.
In this conventional wet type multi-plate friction engaging apparatus
70
, friction materials
53
are usually secured to the inner tooth plates
54
. Further, in another conventional case, friction materials are secured alternately to one side of the outer tooth plates and one side of the inner tooth plates or friction materials are secured to both the outer tooth plates and the inner tooth plates at different radial positions.
However, in the conventional wet type multi-plate friction engaging apparatuses, since the inner tooth plates are rotated at a high speed, lubricating oil included in the friction materials is removed due to high speed rotation, so that the friction materials cannot hold an adequate amount of oil. As a result, during the friction engagement, heat is apt to be generated, thereby causing thermal deformation called heat spot.
Further, in some wet type multi-plate friction engaging apparatuses used in motor bikes, although friction materials are secured to outer tooth plates, since lubricating oil is supplied in an oil bath manner, there arose a problem that squeezing torque in an idling condition is increased.
SUMMARY OF THE INVENTION
The present invention aims to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to provide a wet type multi-plate friction engaging apparatus in which less heat is generated during friction engagement and squeezing torque is minimized.
To achieve the above object, according to the present invention, there is provided a wet type multi-plate friction engaging apparatus in which axially shiftable outer tooth plates provided on an inner peripheral surface of a drum, and inner tooth plates disposed within the drum and spline-connected to an outer peripheral surface of a hub having lubricating oil supply holes open to the outer surface of the hub are arranged coaxially and alternately, so that the outer tooth plates and the inner tooth plates can be frictionally engaging with each other between a piston disposed at a closed end of the drum and a flange disposed at an open end of the drum by an urging force of the piston, and wherein the drum is not rotated or rotated at a low speed, and friction materials are adhered to only the outer tooth plates or the outer tooth plates and the flange.
Incidentally, in the specification, a term “low speed (rotation)” means a speed slower than 1000 rpm.
By adhering the friction materials to only the outer tooth plates and by supplying the oil from the hub side, i.e., central side, the supplying amount of the lubricating oil can be reduced, and even when the inner tooth plates are rotated at a high speed, the oil can be held in the friction materials.
REFERENCES:
patent: 4287978 (1981-09-01), Staub, Jr.
patent: 5421439 (1995-06-01), Hayasaki
patent: 5829566 (1998-11-01), Winks et al.
patent: 6062367 (2000-05-01), Hirayangi et al.
patent: 59-54825 (1984-03-01), None
Sakai Masaki
Tatewaki Hideki
Lorence Richard M.
NSK-Warner K.K.
Vorys Sater Seymour and Pease LLP
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