Note: Descriptions are shown in the official language in which they were submitted.
69
This invention relakes to a disc brake for an
automotive vehicle.
A disc brake has been proposed in which the
caliper is sliaably mounted upon the fixed supporting
member by a pair of circumferentially spaced (with respect
to the rotor), pin-like connectors. Each of the pin-like
connectors, in the present case, incluae a sleeve which is
slidably received in a corresponding aperture in the
caliper, and a bolt which is received through the sleeve
to connect the latter to the fixed support. Consequently,
the caliper can slide on the sleeves in a direction
generally parallel to the axis of the rotation of the rotor.
However, the distance between the apertures must be held
to a close tolerance in a brake of this type. This is so
because the sliding tolerance between the caliper and the
sleeve is quite critical, since all the torque generated
in a brake actuation must be transerred to the torque
member through the sleeves.
SUMMARY OF THE INVENTION
Therefore, the important object of my invention
is to reduce the number of critical manuEacturiny tolerances
- which must be maintained in disc brake manuacture, to
thereby permit manufacture of the brake at a lower cost.
Another important object of my invention is to
design a protective boot which not only prevents interference
with the sliding action of the caliper upon the sleeve by
contaminants, but which also provides a "cushion" to take
up the tolerances between the sleeve and the caliper housing.
The present invention resides in a disc brake
having a rotor, a fixed support mounted adjacent the rotor,
~ caliper, and means for slidably mounting the caliper on
the fixed support for movement generally parallel to the
axls of rotation of the ro-tor. The caliper defines an
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aperture extend~ng generally parallel to the axis of
rotation of the rotor, and th~ slidably mounting means
includes a sleeve slidably received within the aperture.
Fastening means extending through the sleeve the engage
the fixed support, and an annular resilient boot inter-
connecting the sleeve and the wall of the aperture adjace~t
one end of the latter, one end of the boot engaging the
sleeve, the other end of the boo~ terminating in a cushion
disposed in the interface between the sleeve and the wall
of the aperture, the cushion engaging the sleeve and the
wall of the aperture to accommodate the clearance there-
between.
The clearance between the one sleeve and its
corresponding aperture is unequal to the clearance between
the other sleeve and its associated aperture.
DESCRIPTION OF THE DRAWINGS
.
Figure 1 is a cross-sectional view of a disc
brake made pursuant to the teachings of my present
invention;
Figure 2 is an end-elevational view of a disc
brake illustrated in Pigure l; and
Figure 3 is a cross-sectional view taken
substantially along line 3-3 of Figure 2.
DETAILED DESCRIPTION
Referring now to the drawings, a disc brake
generally indicated by the numeral 10 includes a rotor 12
having a pair of opposed friction faces 14 and 16. A
pair of friction elements 18, 20 are disposed adjacent
friction faces 14 and 16, respectively, and are adapted
to be thrust into braking engagement with the friction
faces 14 and 16 when a brake application is effected.
The fixed supporting member, which, in this case, is the
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conventional steering knuckle of the vehicle, is generally
indicated by the numeral 22. Braking torque is transmitted
through the brake caliper generally indicated by the
nu~eral 24 from the friction pads 18, 20 to the fixed
support 22. The caliper 24 is slidably mounted on the
fixed supporting member 22 by a pair of circumferentially
spaced pin-like connecting devices 26 and 28, which permit
sliding movement of the caliper in a plane generally
parallel to the axis of rotation of the rotor 12. ~s
can be most clearly seen in Figure 2, the friction element
18 is in~talled upon the bridge portion 30 of the caliper
24 by a pair of arms 32 9 34, in the manner more completely
disclosed in copending Canadian Patent Application Serial
No. 2377625 filed October 15, 1975, owned by the assignee
of the present invention. The friction element 20 is
installed upon the inwardly extending portion 36 of the
caliper 24 which projects adjacent the friction face 16.
The caliper 24 further includes a bore 34 which slidably
receives a piston 72. The p~ston 72 cooperates with ~he
closed end of the bore to defihe a variable volume chamber
70 therebetween.
The pin-like connectors 26 and 28 are each
received in corresponding apertures 38, 40, respectively.
Referring now to Figure 3, the pin-like connector 26 i9
illustrated in tetail. The connector 26 includes
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a sleeve 42 whlch is slidably received within the aperture 38. A bol~ 44
extend3 through the sleeve 42 and is fastened to the fixed support member 22.
Therefore, the sleeve 42 and bolt 44 mount the caliper 24 for sliding move-
ment with respect to the fixed support 22.
In order to preven~ contaminants from entering the aperture 38
thereby lnterfering with the sliding action of the caliper 24 on the ~leeve 42,
a pair of annular, flexible, resilient boots 46, 48 are provided which inter-
comlect opposite ends of the ~leeve with corresponding ends of the caliper 24
to thereby prevent dir~ and other con~ inants from entering the aperture 38.
One end 50, 52 of the sleeves 46, 48 engage the ~liding ~urface of the
sleeve 42. The oppo~lte ends of the boot~ 46, 48 terminate in a cushion 54, 56
which i9 disposed in the interface between the wall of the aperture 38 and the
oul:er circumferential surface of the sleeve 42. The cu~hions 54, 56 each
include a bead 58, 60 which are received in corresponding groove~ 62, 64 which
are defined in the walls of the aperture 38. The grooves 62, 64 each cooperate
wlth the opposite end of the aperture 38 to define shoulders 66, 68 there-
between. Therefore, the cushions 54, 56 include both the bead portion~ 58, 60
which are received in the grooves, and another portion which extends between
the shoulder~ 66, 68 and the outer circumferential urface of the ~leeve 42.
20 Consequently, the cushions 54, 56 take up any clearance between the sleeve
and the aperture, and also cu~;hlon the sliding effect of the caliper upon the
sleeves. Because the cushions 54 ant 56 take up any clearance between the
sleeve and the caLlper, the spaclng betwaen the apertures 38 and 40 need
not be held to critical tolerances which would make manufacture of the
brake~ difficult.
Of course, each of the pin-like connectors 26, 28 may be made
ident$cal, each havlnE the boots 46, 48 with the corresponding cushions 54, 56
to ~ke up asly clearance betwee~ the sleeve and the wall of their correspond-
ing apertures. Ho~ever, it ig possible to de~i8n the ~leeve of one of the
30 pln like connector~ to ~lide very tl~htly within the corresponding ~perture,
to consequently make the clearance between the sleeve of the other pin-like
connector and the corresponding aperture somewhat larger, with the exces~ clear-
ance being taken up by the cushions 54, 56. This enables the design of the
connector~ to be optimized for the mo~t efficient brake torque tran~fer between
the caliper and the fixed ~upport, without requiring that the distance between
the apertures 38 and 40 be held to a critical tolerance that would make manu-
facture of the brake difficult, since any excess clearance between the apertures
can be taken up by the cushions 54, 56 ln the pin-like connector 26.
In operation, the brake operates a~ a conventional sliding caliper
disc brake. Pressurized fluid 18 introduced from the vehicle's master cylinder
into the v~riable volume chamber 70 defined between the rear face of the
piston 72 and the wall of the bore 74, thereby urging piston 72 to the right
vlewing Figure 1. Movement of the piston 72 to the ri8ht urRes the friction
element 18 into frictional engagement wi~h the friction face 14. Because of
the slldable connection de~cribed hereinabove between the caliper 24 and the
fixed ~upport member 22, the reaction forces acting through the bridge por-
tion 30 and the in~Jardly ex~ending portlon 36 of the callper 24 al80 urge the
friction element 20 into braking engagement with friction face 16, thereby
effecting a brake application. ###
