WO2007108985A2

WO2007108985A2 - Disc brake with cooling device

Info

Publication number: WO2007108985A2
Application number: PCT/US2007/006177
Authority: WO
Inventors: Lawrence W. Savage
Original assignee: Savage Lawrence W
Priority date: 2006-03-16
Filing date: 2007-03-12
Publication date: 2007-09-27
Also published as: WO2007108985A3

Abstract

The invention is embodied in a disc brake with improved heat dissipating capability as shown in figure 1. The disc brake includes an expansion chamber that increases the volume of air passing over the disc (rotor). Wiper blades disturb any boundary layer adjacent to the disc and create vortices resulting in improved dissipation of heat from the disc.

Description

DISC BRAKE WITH COOLING DEVICE TECHNICAL FIELD

The invention relates to a novel disc brake. More specifically, the novel invention relates to a disc brake with improved heat removal capabilities resulting from improved air flow across the surface of the disc.

BACKGROUND OF THE INVENTION

The invention is a disc brake including a disc typically mounted with a hub, friction pads mounted on opposing sides of the disc, and a means to cause the friction pads to engage opposing sides of the disc to retard the rotation of the disc and the hub mounted with the disc. Disc brakes are commonly used in applications including automotive and aircraft wheel assemblies. Disc brakes are also used in machinery applications where rotational control is useful. While disc brakes are well known in the art they suffer certain limitations. In certain severe applications the friction pads cause excessive disc temperatures (900 degrees F+) resulting in rapid failure of braking effectiveness, excessive heating of brake fluid causing its rapid degradation and excessive heating of bearings causing premature failure.

The novel invention reveals improved heat removal of disc brakes including three primary mechanisms for the improved heat removal.

The novel disc brake provides improved flow of ambient air across the surface of the disc (rotor) increasing heat dissipation. An expansion chamber facilitates the improved movement of ambient air from the area of the wheel/disc base circle (surrounding the bearing assembly) to the perimeter of the disc. A pressure differential between the base circle inlet ports and the larger volume of the outlet ports at the rim of the disc chamber assembly causes increased air flow across the surface of the disc. The mechanical pumping of the passing air is facilitated by mechanical drag of the rotating disc surface on the heated air in each chamber, and the volume of air expanding as it is heated from the exposure to the hot disc surface.

The novel disc brake provides disruption of the heated boundary layer of air on the disc surface resulting from interrupting blades intruding into the boundary layer to improve heat dissipation. The interrupting blades create vortices of stirred air along the surface of the disc that tumbles induced ambient air into the super heated air stream at the surface carrying away the heated air before the heat energy has an opportunity to flow through the disc, to bearing assemblies, brake caliper and brake fluid.

The novel disc brake also provides increased surface area surrounding the disc for increased flow of heat energy into the ambient air stream.

SUMMARY OF THE INVENTION

It is the object of the invention to provide a disc brake that is simply and efficiently constructed, and that has improved heat dissipation capabilities.

It is a further object of the invention to provide a disc brake that provides increased braking capacity in severe applications.

It is yet another object of the invention to provide a disc brake that provides improved longevity of hub bearings and bake fluid. It is yet another object of the invention to provide a disc brake that provides a means to quickly interchange parts as maintenance needs dictate.

The present invention is embodied in a disc brake with a cooling chamber and associated components that are attached to a mounting surface. More particularly, the cooling device includes: a. expansion chambers) with increasing volume as the device extends from the centerline of rotation of the disc to the disc periphery; b. inlet ports at the base of the expansion chamber and at the inlet side closest to the brake caliper; c. exhaust ports at the periphery of the expansion chamber and exit furthest from the brake caliper; d. wiper blades on each side of the disc surface constructed of suitable material depending on the specific application; and e. interrupting blades.

The disc brake expansion chamber may be constructed from a variety of materials that vary with the specific application. Most preferably materials that optimize good conductivity and light weight depending on the specific application requirements; and when exposed to the turbulent ambient and heat effected air stream substantially adds to heat energy dissipation. By way of example, in the case of high performance automobiles, the preferable material of construction can be either aluminum, titanium, or high temperature composites. For heavy trucks or off road vehicles, a ferrous metal chamber is most efficacious. For aircraft, a composite (i.e. carbon graphite) material is typically most suitable. The interrupting blades can be constructed of either solid, perforated slotted, fibrous or bimetallic materials or a combination of the above. The specific design of the blade is also dependant on the specific application requirements.

The method of construction of the chamber(s) will vary depending on the volume of production and will include welded construction from segments, casting of the chamber in one or more sections, and molding of composite chambers.

The number of expansion chambers included in the novel disc brake will depend on the severity of service, cost of construction, assembly weight and other specific considerations. In each case, however, the chamber (s) will increase in cross section from the inlet ports to the exit ports to assist in the creation of a pressure differential and attendant air flow into and out of the device.

The inlet ports of the device can assume a variety of shapes depending on the specific application. Consistent with each shape will be the guiding of relatively cool air from the region of the device closest to the wheel bearing and hub into the expansion chamber. The objective of locating the inlet ports close to the wheel

bearing is to cause substantial impingement of cool air on the wheel bearing mounting flange hereby assisting in cooling the bearings. The exhaust ports are positioned at the periphery and end of the novel disc brake furthest from the caliper in a manner and size to create the pressure differential desired and to stiffen the device at its periphery. The specific number and shape of the exit ports may vary with specific applications.

The interrupting blades used to disrupt the boundary layer of hot air can be constructed from various materials suitable for the operating environment and taking into consideration specific facts of each application such as temperature, weight, thermal conductivity, service life, repair and maintenance. As an example, for high performance automobiles, a bimetallic interrupting blade that disrupts the boundary layer when heated and then withdraws with reduced heat load when the brake pressure is reduced is effective. In the case of heavy commercial vehicles, a fixed and robust interruption blade that is in near intimate contact with the disc rotor at all times is more economical. Yet another configuration of interruption blade is constructed of a combination of solid metals or bimetallic metals with a high temperature brush affixed at its edge. In this form, the interruption blade remains undamaged should the wheel/rotor experience a sudden reversal of direction while the blade is in contact with the rotor as in the case of a spinning high performance automobile.

Interrupting blades may be attached to the disc brake in a variety of manners specific to each application. By way of example, in the case of racing automobiles quick change slots may be positioned at the radial side of the device to enable rapid replacement. These interruption blades are distorted to pass into the receiving slot and spring back to mechanically lock in place once the blade passes through the slot. Removal is accomplished by inserting a pin into a receiving notch causing the blade to bend until it appears in the slot. A gripping device such as pliers are then inserted

into notches to withdraw the wiper blade.

Those skilled in the art will appreciate that other means may be use to attach the interrupting blade depending upon the application. Heavy commercial vehicles require robust interrupting blades. In this type of application the interrupting blade may be effectively attached by fixing bolts through the chamber.

Other features and advantages of the present invention will become apparent from the following description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 is a view in perspective of a disc brake illustrating the present invention; FIGURE 2 is a fragmentary view of the expansion cooling chamber of the

disc brake illustrated in FIGURE 1, taken from above; /

FIGURE 3 is a top plan view of the expansion cooling chamber of the disc brake illustrated in FIGURES 1 and 2; FIGURE 4 is a side view of the expansion cooling chamber illustrated in FIGURE 3;

FIGURE 5 is a fragmentary view of the top plan view of the expansion cooling chamber illustrated in FIGURE 3; FIGURE 6 is a fragmentary view of the expansion cooling chamber illustrated in FIGURE 4;

FIGURE 7 is a cross sectional view taken at 7-7 of FIGURE 6; FIGURE 8 is an exploded fragmentary view of the top, side and end of the expansion cooling chamber which shows how the blade interacts with the quick change slot;

FIGURE 9 is the similar view to the one shown in FIGURE 1 with the addition arrows showing the flow of air through the cooling chamber.

FIGURE 10 is a fragmentary view of the top plan view of the cooling chamber shown in FIGURE 3; FIGURE 11 is an end view of the cooling chamber showing the flow of air entering the chamber near its center flowing across the disc and out the exhaust slots.

FIGURE 12 is a view in perspective of a disc brake illustrating an alternative embodiment of the present invention showing cooling chambers located on each side of the friction pads (brake caliper);

FIGURE 13 is a cross sectional view taken at 2-2 of FIGURE 12; FIGURE 14 is a top plan view of the caliper with expansion cooling chamber located on each side of the caliper of the disc brake illustrated in FIGURES 12 and 13;

FIGURE 15 is a side view of the of the caliper with expansion cooling chamber located on each side of the caliper of the disc brake illustrated in FIGURES 12 and 13; and FIGURE 16 is an exploded fragmentary view of the calipers with expansion cooling chamber located on each side of the caliper of the disc brake illustrated in FIGURES 12 and 13.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, a disc brake cooling device generally indicated by the numeral 10 includes an expansion chamber 12 defining ports 14 which induce the flow of ambient air to flow adjacent to the disc (rotor) 16, the expansion chamber defines slots 18 that retain wiper blades 20. The ports 14 have inlets 22 located proximate to the base of the expansion chamber 12 allow ambient air to enter the expansion chamber and flow through the ports 14 to exit the exhaust 24. The ambient air travels in close proximity to the surface of the disc 16 and the surfaces of the expansion chamber 12. The ambient air increases in volume as the air temperature increases resulting from the heat energy being wicked away from the various surfaces such as the disc 16 and sides of the expansion chamber 12. The cross-sectional area of the ports 14 continually increases from the inlet 22 to the exhaust 24. The expanding volume of the heated air is accelerated through the port 14 in a pumping action.

The wiper blades 20 are attached to the expansion chamber and positioned proximate to the surface of the disc 16. The wiper blade 20 location acts to disrupt

and prevent the reestablishment of a barrier layer adjacent to the disc 16. Indeed, vortices of turbulent air are generated by the wiper blades. The lack of a boundary layer and induced vortices augment the flow of ambient air across the surface of the

disc 16 which in turn carries the heat energy from the disc.

Claims

What is claimed:

1. A disc brake with chamber comprising: a. a rotor with a hub, at least one friction pad, and a means to cause the friction pad to engage the side of the rotor; b. one or more chambers located near the perimeter of the rotor; c. the chamber defining at least one port; d. the port defining more than one opening; e. a first opening of the port located proximate to the hub; and f. a second opening of the port located more distant from the hub than said first opening of the port.

2. The disc brake of claim 1 wherein the cross-sectional area of the port near the second opening of the port is greater than the cross-sectional area of the

port near the first opening of the port.

3. The disc brake of claim 1 wherein said chamber defines slots that retain wiper blades.

4. The disc brake of claim 3 wherein the wiper blades are positioned proximate to the surface of the rotor.

5. A disc brake with a chamber comprising: a. a rotor with a hub, friction pads on opposing sides of the rotor, and a means to cause the friction pads to engage opposing sides of the rotor; b. at least one chamber; c. said chamber defining at least one inlet opening; d. said inlet opening proximate to the hub; e. said chamber defining at least one exhaust opening; d. said exhaust opening proximate to the periphery of the chamber and distant from the hub; e. the cross-sectional area of the chamber near said exhaust opening greater than the cross-sectional area of the chamber near the inlet opening; and

f. at least one wiper blade on each side of the rotor.

6. A disc brake with chamber comprising: a. a rotor with a hub, friction pads on opposing sides of the rotor, and a means to cause the friction pads to engage opposing sides of the rotor; b. one or more chambers located on each side of the friction pads; c. the chamber defining at least one port; - d. the port defining more than one opening; e. a first opening of the port located proximate to the hub; and f. a second opening of the port located more distant from the hub than said first opening of the port. A cooling device for a disc brake comprising: a. at least one chamber; b. said chamber defining at least one inlet opening; c. said chamber defining at least one exhaust opening; and d. the cross-sectional area of the chamber near said exhaust opening greater than the cross-sectional area of the chamber near the inlet opening.