Liquid cooled brake assembly

An adjustable fluid cooled brake is provided that integrates the driven shaft and bearings with braking components to form a packaged assembly. The brake includes a driven shaft and two bearings disposed about the driven shaft. The brake further includes a housing disposed about the shaft and friction plates coupled to the housing and driven shaft. One end cap assembly of the brake is coupled to the housing and supports one of the bearings. The end cap assembly includes a pressure plate configured to compress the friction plates. Another end cap assembly is coupled to the housing and supports the other bearing. One of end cap assemblies is spaced from the housing by a spacer that may be adjusted to enable axial movement of the end cap assembly relative to the housing and the corresponding bearing thereby permitting adjustment of the brake.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to liquid cooled brakes and, more particularly, to a packaged assembly incorporating a driven shaft, bearings and brake components.

2. Discussion of Related Art

Conventional liquid cooled disc brakes are sold as a unit and are subsequently mounted on driven shafts. The driven shafts are supported on bearings that are mounted externally of the brake. This arrangement is disadvantageous because the footprint of the shaft and brake assembly is relatively large. Moreover, the separate assembly creates inefficiencies in packaging and in the assembly operation itself. Conventional brakes also preferably contain some means for adjustment of the brake for wear. This need has made it difficult to integrate conventional brakes with shaft and bearing components.

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

SUMMARY OF THE INVENTION

The present invention provides a brake that integrates a driven shaft and bearings with components of an adjustable brake.

A brake in accordance with the present invention includes a driven shaft disposed about a rotational axis and first and second bearings disposed about the driven shaft. The brake further includes a housing disposed about the driven shaft. A first friction plate is coupled to the driven shaft for rotation therewith and is axially movable relative to the driven shaft. A second friction plate is coupled to the housing and is fixed against rotation relative to the housing. The second friction plate defines a fluid jacket configured for passage of a fluid. The brake further includes a first end cap assembly coupled to the housing and supporting the first bearing. The first end cap assembly includes a pressure plate configured for selective movement in a first axial direction towards the first and second friction plates. The brake further includes a second end cap assembly coupled to the housing and supporting the second bearing and a spacer disposed between the one of the first and second end cap assemblies and the housing. Adjustment of the spacer enables axial movement of the one end cap assembly relative to both the housing and a corresponding one of the first and second bearings.

A brake in accordance with the present invention represents a significant improvement relative to conventional liquid cooled disc brakes. In particular, the inventive brake integrates a driven shaft and bearings with components of a liquid cooled disc brake thereby reducing the footprint of the assembly and making assembly and packaging more efficient. Further, the inventive brake accomplishes these objectives while enabling adjustment of the brake to compensate for wear.

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 shaft12, bearing assemblies14,16, a housing18, two sets of friction plates20A-C,22A-B, two end cap assemblies24,26, and a spacer28.

Shaft12provides torque to a rotatable device (not shown) and is driven a motor (not shown) or other torque generating device. Shaft12may be made from conventional metals and metal alloys. Shaft12is disposed about a rotational axis30. Shaft12may be a unitary body or, as shown in the illustrated embodiment, shaft12may include a plurality of members such as spear32, inner hub34and outer hub36. Spear32is driven by a torque generating device and may be coupled at one end to a draw works shaft (not shown). Spear32extends through a bore38in inner hub34and hub34may be coupled to spear32through a key/keyway or spline relationship or in other ways customary in the art. Inner hub34has an outer diameter that varies along the axial extent of hub34to provide a plurality of shoulders and steps used to support outer hub36and components of bearing assemblies14,16. Outer hub36is coupled to inner hub34. In particular, body40of outer hub36defines one or more keys42configured to be received within corresponding keyway(s) in inner hub34. Body40also has a plurality of spline teeth44on a radially outer surface for a purpose described hereinbelow.

Bearing assemblies14,16are provided to allow rotation of shaft12relative to components of brake10. Bearing assembly14is disposed between inner hub34of shaft12and end cap assembly24. Bearing assembly16is disposed between inner hub34of shaft12and end cap assembly26. Each bearing assembly14,16includes a bearing carrier46,48, a bearing50,52, and seals54,56and58,60respectively. Bearing assembly16may further includes a body, such as a transducer wheel62, coupled to shaft12, and a sensor64.

Bearing carriers46,48are provided position and support bearings50,52. Each of carriers46,48may include inner and outer members66,68, and70,72, respectively, that are joined together during assembly by fasteners74,76, respectively, such as bolts, screws, pins or adhesives. Members66,68define a recess and opposed shoulders configured to receive bearing50. Similarly, members70,72define a recess and opposed shoulders configured to receive bearing52. Outer members66,72, may each include a lubricant passage (only one of which is shown, in member66of carrier46) in which a zerk78is received for introducing lubricants to the respective bearings50,52. Member72may also define a bore80in which sensor64may be disposed. End cap assembly24supports bearing carrier46and bearing50. As described in greater detail below, end cap assembly24is axially movable relative to bearing carrier46and bearing50, sliding along the radially outer surface of bearing carrier46. End cap assembly26supports bearing carrier48and bearing52. Member72of bearing carrier48defines a shoulder configured to receive end cap assembly26.

Bearings50,52, are provided to allow relative rotation of shaft12. Bearings50,52are conventional in the art and may comprise spherical roller bearings. Each bearing50,52may include a unitary cone82,84, respectively, defining a pair of inner races for two sets of spherical rollers86,88and90,92, with a pair of cups94,96and98,100forming outer races for the rollers86,88and90,92, respectively. It should be understood, however, that a variety of conventional bearing structures could be employed.

Seals54,56and58,60, are provided to retain lubricant for bearings50,52, and to prevent entry of dirt and other contaminants. Seals54,56and58,60are conventional in the art and are disposed at either end of bearing carriers46,48, with seals54,60disposed between input hub34and members66,72, of carriers46,48, and seals56,58, disposed between input hub34and members68,70, of carriers46,48.

Transducer wheel62and sensor64provide information regarding the rotational position of shaft12. Wheel62and sensor64are conventional in the art. Wheel62is coupled to input hub34of shaft12and may consist of a notched wheel surrounding input hub34as is known in the art. It should be understood, however, that a variety of different bodies could be used in place of transducer wheel62as position indicators. Sensor64is configured to generate a signal indicative of a position of wheel62. Sensor64is conventional in the art and may comprise a Hall effect sensor or other conventional sensor. Sensor64may be disposed within bore80of member72of bearing carrier48or may be disposed outside of carrier48. One advantage of the present invention is that wheel62and sensor64can be integrated into the packaged brake assembly.

Housing18provides structural support to the other components of brake10. Housing18may be made from conventional metals, metal alloys and/or plastics. Housing18is disposed about shaft12and may be centered about the rotational axis30. Housing18may be substantially circular in shape and may be unitary in construction or composed of multiple pieces joined together. Housing18defines axially extending bores102,104at either end configured to receive fasteners106,108, used to connect end cap assemblies24,26, respectively, to housing18. Housing18also defines a plurality of radial openings110sized for receipt of hoses and connectors (not shown). Housing18includes a plurality of spline teeth112on a radially inner surface for a purpose described hereinbelow. One or more mounting brackets114,116, or feet, may extend from housing18to allow brake10to be mounted to a surface extending substantially parallel to axis30.

Friction plates20A-C are provided to transmit a braking torque to friction plates22A-B and to shaft12upon engagement of plates20A-C,22A-B. Friction plates20A-C may include a plurality of spline teeth118disposed on radially outer surfaces of plates20A-C that are configured to mate with teeth112of housing18thereby preventing relative rotation of plates20A-C relative to housing18, but allowing axial movement of plates20A-C relative to housing18. Friction plates20A-C may be biased apart by springs120that are disposed between each pair of plates20A-C and are disposed about pins122extending through plates20A-C. Although three friction plates20A-C are shown in the illustrated embodiment, it should be understood that the number of friction plates can be varied to vary braking torque. Each of friction plates20A-C includes one or more plates124and a fluid jacket126.

Plates124are conventional in the art and may be made from a variety of conventional metals and metal alloys including iron or copper. Plates124may be connected to one or both sides of each fluid jacket126using fasteners128such as bolts or screws or pins.

Fluid jackets126are 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. Jackets126are conventional in the art and include an annular body that defines a fluid manifold through which liquid circulates and which provides a surface on which plates124are mounted. Jackets126may define a plurality of concentric flow passages128and radial flow passages130that place concentric passages128in fluid communication with fluid inlets132and outlets (not shown).

Friction plates22A-B are provided to transfer braking torque from friction plates20A-C to shaft12. Friction plates22A-B may be made from conventional metals and metal alloys such as iron and copper. Plates22A-B include a plurality of spline teeth136at a radially inner surface that are configured to engage with teeth44on hub36of shaft12to couple friction plates22A-B to shaft12. Plates22A-B may include a conventional friction material138connected to each side of plate22A-B by fasteners140such as bolts or screws. Again, although only two plates22A-B are shown in the illustrated embodiment, it should be understood that the number of plates22can be varied to vary braking torque.

End cap assembly24closes one end of housing18and provides a fixed surface against which friction plates20A-C,22A-B are selectively urged to provide braking torque to shaft12. Assembly24includes an end plate142that is annular in construction. Plate142is fastened to housing18by fasteners106Plate142also supports bearing50. In particular, plate142is sized to receive bearing carrier46of bearing assembly14. As discussed hereinbelow, plate142may be adjusted axially relative to bearing50and bearing carrier46in accordance with one aspect of the present invention. A seal144may be disposed between plate142and bearing carrier46on an outboard side of plate142to prevent dirt and other contaminants from entering brake10.

End cap assembly26closes an opposite axial end of housing18and provides support for a brake actuator. In the illustrated embodiment, end cap assembly26includes a plate146that is annular in construction and which is fastened to housing18using one or more fasteners108. Plate146defines an annular recess148configured to receive an expandable bladder150that bears against a pressure plate152. Plate146also defines an axial bore154through which pneumatic or hydraulic fluid is provided to bladder150via a hose (not shown). When fluid is supplied to bladder150, bladder150expands and urges pressure plate152in an axial direction against the force of springs120to compress, and cause engagement of, friction plates20A-C,22A-B. When fluid pressure is removed from bladder150, springs120bias friction plates20A-C,22A-B apart. Although the illustrated embodiment employs a single actuator acting as a tension brake, it should be understood that various actuators could be employed and that multiple actuators could be used to provide an emergency brake.

Spacer28provides means for adjusting an axial position of end cap assembly24relative to housing18and also to bearing50. Although spacer28is illustrated inFIG. 1for use in adjusting the axial position of end cap assembly24relative to housing18and bearing50, it should be understood that spacer28could be employed on the opposite side of brake10to allow adjustment of the axial position of end cap assembly26relative to housing18and bearing52. Spacer28may comprise one or more shims disposed between end cap assembly24and housing18. The shims may be disposed about the circumference, or a portion of the circumference, of fasteners106. In accordance with one embodiment of the present invention, a plurality of spacers—each consisting of a plurality of shims—are circumferentially spaced from one another between end cap assembly26and housing18with each spacer or set of shims disposed about two circumferentially adjacent fasteners. Each spacer, or shim in the corresponding set of shims, has a closed circular aperture through which a fastener106extends and a U-shaped or other open aperture through which a circumferentially adjacent fastener extends. As the brake wears, one or more shims may be removed by loosening the fastener extending through the closed aperture in each shim (the fastener extending through the open aperture in the shim may remain in place) thereby enabling end plate142to be drawn closer to housing18and to compensate for wear. Because some fasteners are not removed, end cap assembly26and other components do not need to be removed during the adjustment. In accordance with one aspect of the present invention, end cap assembly24continues to provide support to bearing50while being axially adjustable. End plate142moves axially inwardly relative to bearing carrier46of bearing assembly14.

A brake in accordance with the present invention represents a significant improvement relative to conventional brakes. The inventive brake10integrates shaft12and bearings50,52, with components of a liquid cooled disc brake thereby reducing the footprint of the assembly and making assembly and packaging more efficient. Further, the inventive brake10accomplishes these objectives while enabling adjustment of the brake to compensate for wear.

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.