Balanced flow cooling water jacket

A fluid jacket for a disc brake is provided that promotes a balanced flow of cooling fluid throughout the fluid jacket to most effectively remove heat from the disc brake. The fluid jacket includes an annular body configured for engagement with a friction surface. The annular body defines a plurality of concentric flow passages. The annular body further defines first and second axial flow passages in fluid communication with first and second flow passages, respectively of the plurality of concentric flow passages, with the first and second flow passage separated by a third concentric flow passage. The annular body further defines a radial flow passage extending between the first and second axial flow passages, and a fluid inlet in fluid communication with the radial flow passage.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to liquid cooled brakes and, more particularly, to a fluid jacket for use in liquid cooled brakes.

2. Disclosure of Related Art

A conventional disc brake employs two sets of friction plates that are interleaved with each other to transmit a braking force. The friction plates may be made from copper to enhance frictional heat transfer within the brake. Typically, one set of plates is fixed against rotation relative to a stationary body such as a brake housing, but is axially movable relative to the stationary body. The other set of plates rotate with a rotating body such as a driven shaft, but are also axially moveable relative to the rotating body. An actuator is employed to bring the plates into engagement through which the rotating body is braked.

Braking a rotating body results in a conversion of mechanical energy to heat energy. In many instances, it is desirable to provide for effective removal of some of the heat developed from the brake structure. One method of removing heat from a disc brake is to use a liquid to cool the brake structure and transfer heat out of the brake structure. In one conventional form of a liquid cooled disc brake, one set of the friction plates define fluid jackets for circulating a cooling fluid therethrough to reduce the heat generated in the brake by the frictional engagement of the friction plates.

One conventional fluid jacket has a plurality of concentric flow passages and a radial flow passage that is in fluid communication with each of the concentric flow passages. A fluid inlet and outlet communicate with the radial flow passage. In theory, fluid is simultaneously delivered to each of the concentric passages after entering the radial flow passage from the fluid inlet. In practice, however, it has been determined that the flow of fluid is uneven within and among the concentric passages. In particular, fluid flow in the radially inner concentric passages is relatively high, while fluid flow in the radially outer concentric passages is relatively low. Effective fluid flow in the radially outer concentric passages is especially important since more heat is generated toward the radially outer portion of the friction plate which rotates at a faster speed than the radially inner portion of the plate.

The inventors herein have recognized a need for a fluid jacket for a disc brake that will minimize and/or eliminate one or more of the above-identified deficiencies.

SUMMARY OF THE INVENTION

The present invention provides a fluid jacket for a disco brake that results in improved fluid flow.

A fluid jacket in accordance with the present invention includes an annular body configured for engagement with a friction surface. The annular body defines a plurality of concentric flow passages. The annular body further defines a first axial flow passage in fluid communication with a first flow passage of the plurality of concentric flow passages. The annular body further defines a second axial flow passage in fluid communication with a second flow passage of the plurality of concentric flow passages. The second flow passage is separated from the first flow passage by a third flow passage of the plurality of concentric flow passages. The annular body further defines a radial flow passage extending between the first and second axial flow passages and a fluid inlet in communication with the radial flow passage.

A fluid jacket in accordance with the present invention represents a significant improvement relative to conventional fluid jackets used in disc brakes. In particular, the inventive fluid jacket significantly improves fluid flow among the concentric flow passages of the fluid jacket promoting a more balanced fluid flow among the passages. As a result, the fluid jackets more effectively dissipate heat from the brake.

These and other advantages of this invention will become apparent to one skilled in the art from the following detailed description and the accompanying drawings illustrating features of this invention by way of example.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Referring now to the drawings wherein like reference numerals are used to identify identical components in the various views,FIG. 1illustrates a brake10in accordance with the present invention. Brake10may be provided for heavy duty industrial use (e.g., on oil drilling equipment). Brake10includes a housing12, two sets of friction plates14A-B,16, and an end cap assembly18.

Housing12provides structural support to the other components of brake10. Housing12may be made from conventional metals, metal alloys and/or plastics. Housing12is disposed about a driven shaft20and may be centered about the rotational axis22of the shaft20. Housing12may be substantially circular in shape and unitary in construction. Housing12defines axially extending bores24,26at either end configured to receive fasteners28,30used to connect a friction plate14and end cap assembly18, respectively, to housing12. Housing12also defines a plurality of radial openings32sized for receipt of hoses and connectors (not shown).

Friction plates14A,14B are provided to transmit a braking torque to friction plate16and shaft20upon engagement of plates14A,14B,16. Friction plate14A is fixed to housing12by fasteners28extending through friction plate14A. Friction plate14B is coupled to housing12through the use of spline teeth34,36on a radially inner surface of housing12and a radially outer surface of plate14B, respectively. In this manner, plate14B is fixed against rotation relative to housing12, but is axially movable relative to housing12. Although only one movable plate14B is shown in the illustrated embodiment, it should be readily understood that additional plates14B (and friction plates16) could be interleaved and used to provide increased braking torque). Each of friction plates14A,14B includes one or more plates38and a fluid jacket40in accordance with the present invention (described in greater detail hereinbelow). Plates38are conventional in the art and may be made from a variety of conventional metals and metal alloys including iron or copper. Plates38may be connected to one or both sides of each fluid jacket40using fasteners42such as bolts or screws or pins.

Friction plate16is provided to transfer braking torque from friction plates14A, B to shaft20. Friction plate16may be made from conventional metals and metal alloys such as iron and copper. Plate16is coupled to a hub44fixed to shaft20(or directly to shaft20) through the use of spline teeth46,48on a radially inner surface of plate16and a radially outer surface of hub44(or shaft20), respectively. Plate16may include a conventional friction material50connected to each side of plate16by fasteners52such as bolts or screws. Again, although only plate16is shown in the illustrated embodiment, it should be understood that additional plates16could be interleaved with additional plates14B to increase braking torque.

End cap assembly18closes one end of housing12(opposite friction plate14A) and provides support for brake actuators. In the illustrated embodiment, end cap assembly18includes a plate54that is annular in construction and which is fastened to housing12using one more fasteners30. Plate54defines an annular recess56configured to receive an expandable bladder58that bears against a pressure plate60. Plate54also defines an axial bore62through which pneumatic or hydraulic fluid is provided to bladder58via a hose (not shown) and a stepped diameter bore64through which a fastener66extends. Fastener66is surrounded by a spring68disposed in a larger diameter portion of bore64and extends through plate54into friction plate14B. When fluid is supplied to bladder58, bladder58expands and urges pressure plate60in an axial direction against the force of spring68to compress, and cause engagement of, friction plates14A-B,16. When fluid pressure is removed from bladder58, spring68biases friction plate14B in a second axial direction to its original position. Although the illustrated embodiment employs a single actuator acting as a tension brake, it should be understood that the fluid jackets40described herein could be employed in a variety of brakes.

Referring now toFIGS. 2-3, a fluid jacket40in accordance with the present invention will be described and illustrated. Jacket40is provided to allow for circulation of a cooling liquid such as water or another conventional liquid within brake10to allow for transfer of frictional heat generated within brake10. Jacket40includes an annular body70that defines a fluid manifold through which liquid circulates and provides a surface on which plates38(SeeFIG. 1) are mounted. Body70may define a plurality of concentric flow passages72,74,76,78,80,82,84a plurality of axial flow passages86,88,90,92a plurality of radial flow passage94,96a fluid inlet98and a fluid outlet100.

Concentric flow passages72,74,76,78,80,82,84, are provided for circulation of a cooling liquid adjacent to plates38and along the entire radial and circumferential extent of plates38. In the illustrated embodiment, flow passages72,74,76,78,80,82,84are disposed on only one axial face of body70of jacket40. Referring toFIG. 1, however, it should be understood that similar passages may be formed on the opposite of body70of jacket40depending on the location of the friction plates14A,14B containing jacket40(e.g., if friction plates16were disposed on either side of friction plate14B). It should also be understood that, although the illustrated embodiment of the invention shows seven (7) concentric flow passages72,74,76,78,80,82,84, the number of flow passages could vary. In the illustrated embodiment, flow passage72comprises the radially innermost concentric flow passage while flow passage84comprises the radially outermost concentric flow passage. Flow passages74,76,78,80,82are disposed between flow passage72,84. Referring toFIG. 3, flow passages72,74,76,78,80,82,84are defined by concentric annular walls, such as wall102, and may be in fluid communication with each other at partitions104that are made in walls102at diametrically opposite positions within fluid jacket40. The radial width of the flow passages may be equal as shown in the illustrated embodiment.

Axial flow passages86,88,90,92provide fluid communication between concentric flow passages72,74,76,78,80,82,84and radial flow passage94,96, respectively. Axial flow passages86,88,90,92, are each in direct fluid communication with at least one concentric flow passage72,74,76,78,80,82,84. In the illustrated embodiment, axial flow passages,86,90, are in fluid communication with the radially outermost concentric flow passage84and are also in fluid communication with the flow passage82disposed radially inwardly of passage84. A diameter of each of axial flow passages86,90extends across the full radial length of concentric flow passage84and across only a portion (approximately one-half in the illustrated embodiment) of the radial length of concentric flow passage82. Axial flow passages88,92, are in fluid communication with adjacent concentric flow passages74,76. A diameter of each of axial flow passages88,92extends across only a portion (less than one-half in the illustrated embodiment) of the radial length of each of concentric flow passages74,76. The diameters of axial flow passages88,92, are smaller than the diameters of axial flow passage86,90. In the illustrated embodiment, no portion of radially innermost concentric flow passage72or flow passages78,80are in direct fluid communication with any of axial flow passages86,88,90,92. Accordingly, the concentric flow passages74,76, and82,84, with which the axial flow passages,88,92, and86,90, respectively, are in direct fluid communication are separated by concentric flow passages78,80.

Radial flow passages94,96provides fluid communication between axial flow passages86,88,90,92, and fluid inlet98and outlet100. Radial flow passages94,96extend between axial flow passages86,90and88,92, respectively. The diameters of radial flow passages94,96, may be constant between axial flow passages86,90and88,92, respectively,. Radial flow passage94,96may be located at diametrically opposite locations within jacket40and may be axially aligned with partitions104in annular walls102forming concentric flow passages72,74,76,78,80,82,84.

Fluid inlet98and fluid outlet100are provided for the introduction and exit of fluid from fluid jacket40. Inlet98and outlet100may be located at radially outer points on jacket40. Inlet98and outlet100may have a diameter greater than the diameter of radial flow passages94,96and may be sized, and threaded, to receive a fluid connector (not shown).

A fluid jacket in accordance with the present invention represents a significant improvement relative to conventional fluid jackets. In particular, the inventive fluid jacket significantly improves and optimizes fluid flow among the concentric flow passages of the fluid jacket promoting a more balanced fluid flow among the passages. As a result, the fluid jackets more effectively dissipate heat from the brake.

While the invention has been shown and described with reference to one or more particular embodiments thereof, it will be understood by those of skill in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.