Brakes – Wheel – Axially movable brake element or housing therefor
Patent
1994-11-17
1996-09-24
Young, Lee
Brakes
Wheel
Axially movable brake element or housing therefor
188264D, 188264CC, 188264P, F16D 5502
Patent
active
055581838
DESCRIPTION:
BRIEF SUMMARY
This invention relates to disc brakes for motor vehicles and in particular but not exclusively to disc brakes for high performance cars.
In a typical disc brake, a brake caliper straddles the outer peripheral margin of a brake disc, the caliper having at least one hydraulic cylinder therein for applying friction pads to each side of the disc. The calipers are of two basic types, fixed calipers which have hydraulic cylinders on both sides of the disc, and moving calipers in which typically the hydraulic cylinder is on one side of the disc for direct application of friction pad(s) on that side of the disc, and the friction pad(s) on the other side of the disc are applied by the reaction movement of the caliper.
With disc brakes of the type fitted to motor cars the friction pads engage opposed sectors of the disc over arcs of varying circumferential extent depending upon the braking requirements. When the brakes are applied, the pads grip onto the disc and friction heat is generated so that the brake disc can become red hot. In extreme applications, such as in racing cars, the calipers themselves may become overheated which can cause boiling of the hydraulic brake fluid.
It is an object of the present invention to provide an improved form of disc brake caliper in which problems of overheating are mitigate.
Thus according to the present invention there is provided a disc brake caliper having two limbs which in use straddle a brake disc to support friction pads on each side of a brake disc for engagement with opposed sectors of the disc, and at least one of said limbs housing at least one hydraulic piston and cylinder assembly for operation of the brake, said caliper being characterised in that said at least one limb includes a cooling fluid passageway which at least partially surrounds the or each piston and cylinder assembly to cool the hydraulic fluid of the assembly.
Each limb of the caliper may house at least one piston and cylinder assembly which is at least partially surrounded by a cooling fluid passageway.
The or each fluid passageway may be formed as an internal gallery with at least partially encircles the side wall of the or each assembly to improve heat transfer from the or each assembly to coolant fluid within the gallery.
Conveniently the two caliper limbs are joined by circumferentially spaced bridges which pass over the outer periphery of the brake disc, and the fluid passageways in the two limbs are interconnected by passage means in either or each bridge.
The preferred coolant is water which may be circulated through the passageways by means of a pump.
The invention also provides a method of casting a disc brake caliper or caliper part which includes at least one operating piston bore, said method being characterised by comprising the steps of forming a female mould impression of the required external shape of the caliper or caliper part in a casting medium, forming a male core shaped to define a cooling gallery which at least partially surrounds the region of the caliper or caliper part which is to include the or each piston bore, supporting the core in the correct relationship relative to the mould impression to provide the desired cooling gallery, pouring a casting material into the mould void formed between the impression and core, allowing the casting material to solidify, removing the cast caliper or caliper part from the mould impression, and removing the core from within the cast caliper or caliper part.
The invention will be described by way of example and with reference to the accompanying drawings in which:
FIG. 1 is a plan view of a disc brake caliper according to the present invention;
FIG. 2 is a radial cross section through disc brake caliper of FIG. 1 taken on the line 2--2 with pistons and pads removed;
FIG. 3 is a side elevation, partly in section, of the caliper of FIG. 1;
FIG. 4 is a radial cross section through a casting from which one caliper limb is formed;
FIG. 5 is a section on the line 5--5 of FIG. 4;
FIG. 6 is a radial section, corresponding to FIG. 4 showing core r
REFERENCES:
patent: 3850267 (1974-11-01), Odier
patent: 4799575 (1989-01-01), Kroniger
patent: 5002160 (1991-03-01), Weiler et al.
patent: 5394963 (1995-03-01), Deane et al.
patent: 5445242 (1995-08-01), Pogorzelski et al.
Automotive Products plc
Germain Lee A.
Milliken Paul E.
Young Lee
LandOfFree
Disk brake does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Disk brake, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Disk brake will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1923095