Air disc brake

Details Air disc brake Air disc brake

1999-10-07

2001-05-15

Oberleitner, Robert J. (Department: 3613)

Brakes

Wheel

Axially movable brake element or housing therefor

C188S072300

Reexamination Certificate

active

06230851

ABSTRACT:

TECHNICAL FIELD
The present invention relates to an air disc brake in which a pair of brake blocks disposed oppositely across a disc-like rotor rotating integrally with a wheel are pressed against the rotor by air pressure to thereby generate a braking force. Particularly it relates to an air disc brake adapted for a railroad vehicle.
BACKGROUND ART
As an air disc brake for a railroad vehicle, a lever-operated air disc brake as shown in
FIG. 4
has been proposed in Japanese Patent Unexamined Publication Hei. 7-9956, or the like.
The air disc brake
1
is configured as follows. A pair of brake blocks
4
,
4
are disposed in opposition to each other so as to put therebetween a disc-like rotor
3
rotating integrally with a wheel
2
. The brake blocks
4
,
4
are driven by a pair of lever members
6
,
6
and a single air chamber
8
. The tip ends of the lever members
6
,
6
are connected to the brake blocks
4
,
4
respectively, and the single air chamber
8
is disposed between the opposite base end portions of the pair of lever members
6
,
6
so as to turn the level members
6
,
6
.
The air chamber
8
is provided fixedly to a truck frame
7
of a railroad vehicle. When air pressure is supplied to the air chamber
8
, a pair of operation plates
8
a
connected to the lever members
6
respectively are displaced so as to project out in the directions of the arrows (a) to thereby turn the lever members
6
around rotation fulcrums
9
in the directions of the arrows (b) respectively so that the brake blocks
4
are pressed against the rotor
3
.
The lever members
6
are urged by return springs
10
respectively in the directions that the brake blocks
4
are separated from the rotor
3
.
In the aforementioned lever-operated air disc brake, however, there arose a problem that not only the number of parts increased but also the size, weight and cost increased because of provisions of the lever members
6
and a mechanism for rotatably supporting the lever members
6
.
Further, since the lever-operated air disc brake was configured so that the swelling displacement of the air chamber
8
caused by the supply of air pressure was transmitted to the brake blocks
4
through the lever members
6
, the responsibility of the brake blocks
4
was lowered correspondingly to the interposition of the lever members
6
even in the case where air pressure supply control was performed at a high speed. Therefore, there arose a problem that the high-speed air pressure control was hardly reflected in improvement of the responsibility of the brake blocks
4
.
Further, in the case of a railroad vehicle, there was a possibility that an axle might be moved within a range of about ±7 mm in an axial direction, a vertical direction or another direction at the time of braking. In the case of the aforementioned lever-operated air disc brake, an impact load acted on the rotation fulcrums
9
or the lever members
6
because of the aforementioned movement of the axle at the time of braking. Accordingly, there was a problem that constituent parts were fatigued easily.
The present invention is designed upon the aforementioned circumstances, and an object of the present invention is to provide an air disc brake in which the number of parts can be reduced to thereby attain reduction in size and weight and reduction in cost and in which air pressure supply control can be performed at a high speed to thereby improve responsibility easily. Further, it is another object of the present invention to provide an air disc brake in which an impact load acting on constituent parts due to the movement of an axle at the time of braking can be relaxed to thereby reduce the fatigue of the constituent parts caused by the impact load. Thus, the air disc brake according to the present invention is particularly adapted for a railroad vehicle.
DISCLOSURE OF INVENTION
In order to achieve the above object, according to the present invention, there is provided an air disc brake in which a pair of brake blocks disposed in opposition to each other so as to put therebetween a rotor rotating integrally with a wheel are pressed against the rotor by air pressure to thereby generate a braking force, wherein a pair of leg portions in opposition to each other so as to put therebetween the rotor are provided in a caliper body fixed to a truck frame, the pair of leg portions being provided with cavities serving as spaces for receiving air chambers respectively; and each of the air chambers includes a housing plate material attached to the leg portion so as to cover the cavity and provided with air pressure supply port formed therein, a diaphragm defining a pressure chamber in the cavity and between the housing plate material and the diaphragm so that the diaphragm is moved in the cavity so as to be swollen toward the rotor side by air pressure supplied to the pressure chamber, a piston having a base end in contact with the diaphragm and a tip end protruded from the cavity and provided with a head portion connected to the brake block, and a return spring provided in the cavity for urging the piston to move apart from the rotor.
Further, according to the aforementioned configuration, the swelling displacement of the air chambers is directly transmitted to the brake blocks. In comparison with the conventional air disc brake having lever members and mechanisms of rotatably supporting the lever members, not only the number of parts can be reduced by the omission of the lever members and the mechanisms of supporting the level members to thereby simplify the structure but also response lag due to members interposed between the air chambers and the brake blocks can be eliminated.
Further, the movement of the axle at the time of braking is permitted by the elastic deformation of the diaphragms and return springs supporting the pistons in the air chambers so that an impact load acting due to the movement of the axle at the time of braking can be relaxed.
Preferably, in the above air disc brake, the return spring may be a spiral type compression coiled spring which is formed so that the diameter of winding of a spring wire material is reduced gradually in a direction of from one end side to the other end side.
In such a configuration, the return springs are configured so that the small-diameter spring wire is set in the inside of the large-diameter spring wire in the case where the return springs are compressively deformed by the swelling displacement of the diaphragms, so that the space occupied by the return springs in the axial direction becomes very small. Accordingly, the return springs can be set in cavities of the leg portions of the caliper body so as to save a space. This can contribute to reduction in size of the brake apparatus.


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patent: 3759147 (1973-09-01), Johnsson et al.
patent: 3955480 (1976-05-01), Wosegien
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patent: 4077499 (1978-03-01), Baram
patent: 4793449 (1988-12-01), Smith
patent: 4867280 (1989-09-01), Von Gruenberg et al.
patent: 5826686 (1998-10-01), Rike
patent: 5845747 (1998-12-01), Rike et al.
patent: 5934417 (1999-08-01), Kobayashi et al.
patent: 6073733 (2000-06-01), Kapanowski
patent: 6079312 (2000-06-01), Plantan
patent: 6116385 (2000-09-01), Ring
patent: 46-3866 (1971-11-01), None
patent: 56-141863 (1981-10-01), None
patent: 58-5541 (1983-01-01), None
patent: 60-49141 (1985-03-01), None
patent: 63-11936 (1988-01-01), None
patent: 7-9956 (1995-01-01), None

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