Heat dissipation system for audio amplifier

A heat dissipation system for an audio amplifier is presented, including a housing having a plurality of apertures therein; at least one completely enclosed air tunnels, each air tunnel extending between one of the apertures in the housing and another of the apertures in the housing, each air tunnel at least partially defined by a pair of opposed heat sinks mounted within the housing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the cooling of electronic apparatus. More specifically, the present invention presents a cooling system for a rack mounted audio amplifier.

2. Description of the Prior Art

Oftentimes, a limiting factor in the design of electronic equipment such as audio amplifiers, is heat dissipation. With the advent of new and more sophisticated electronic components, the heat generated in the apparatus, if not properly dissipated, can often be so great as to degrade apparatus performance.

The need for greater heat dissipation is balanced by the sensitivity of sophisticated electronic components to contamination by dust or other particulate matter, which can often be borne in the air passed through the apparatus for cooling purposes. Moreover, in an application such as an audio amplifier, noise generation by the cooling system must, of necessity, be kept to a minimum or eliminated entirely.

Traditionally, audio amplifiers have been cooled by the use of a fan drawing air into the amplifier housing through openings in the housing. The air then flows freely throughout the interior of the housing and exits through an outlet in the housing. More recently, partially enclosed cooling system designs, have been suggested. For instance, in U.S. Pat. No. 5,726,603 to Chawa et al., a forced air cooling tunnel having a plurality of fans drawing air through the tunnel is illustrated. In a similar vein is a device sold by Peavey Electronics as its “Turbo/V Cooling” which utilizes a partially closed tunnel, partially defined by a pair of diverging heat sinks. And, in U.S. Pat. No. 6,259,798 to Perkins et al., a passive radiator-cooled electronic heat sink housing for a powered speaker is described.

In U.S. Pat. No. 5,946,188, Rochel et al. disclose a pair of heat sinks, each formed as first and second tunnels connected by a Peltier device toward one end of the tunnels. One of the heat sinks abuts electronic components and passes heat to be dissipated into the interior tunnel where air flow carries the heated air to the second tunnel from which it is exhausted.

Nothing in the art, however, provides an audio amplifier cooling system which is capable of maximizing heat dissipation by heat sinks while still isolating the interior of an amplifier from air borne particulates and noise. Accordingly, there is a continuing need in the art for an improved cooling system for an audio amplifier.

SUMMARY OF THE INVENTION

The present invention provides an audio amplifier having an improved cooling system. The inventive cooling system comprises a plurality of completely enclosed cooling tunnels, each cooling tunnel defined between a tunnel inlet formed in the housing of the audio amplifier and at least one tunnel outlet formed in the housing of the audio amplifier at a different location. The tunnels are at least partially defined by a pair of opposed heat sinks, each of the heat sinks in operative connection with an electronic component. The heat sinks each preferably comprise a plurality of fins extending into the respective tunnels, in order to increase the available heat sink surface area exposed to air flow. Preferably, the cooling tunnel inlets are located at the rear of the housing whereas the cooling tunnel outlets are located at the front of the housing.

In another embodiment of the present invention, the cooling tunnels each comprise a plurality of branches extending through the housing, each of the branches also at least partially defined by pairs of opposed heat sinks.

In an additional embodiment, the inlet to the cooling tunnels is defined by a venturi section capable of increasing the air speed of incoming cooling air.

Accordingly, it is an object of the present invention to provide an improved cooling system for an audio amplifier.

Another object of the invention is to provide a cooling system for an audio amplifier which isolates cooling air as it passes through the housing of the amplifier.

Still another object of the present invention is to isolate noise from the cooling system from the electronic components of the audio amplifier.

Yet another object of the invention is a venturi inlet for a cooling system for an audio amplifier capable of increasing the velocity of air flow through the cooling system.

These objects and others which will be apparent to the skilled artisan can be achieved by the provisions of a heat dissipation system for an audio amplifier, which includes a housing having a plurality of apertures, which act as inlets and outlets therein; and at least one, and most preferably a plurality of, completely enclosed air tunnels, each air tunnel extending between one of the apertures (i.e., inlets) in the housing and another of the apertures (i.e., outlets) in the housing, each air tunnel at least partially defined by a first pair of opposed heat sinks mounted within the housing. Advantageously, the tunnels are isolated from the electronic components of the amplifier. Moreover, the heat sinks each preferably have at least one fin extending into the interior of the tunnel.

The audio amplifier can comprise at least one printed circuit board having a plurality of electronic components mounted thereon, wherein each of the heat sinks is in operative contact with at least one of the electronic components.

In the inventive system a fan can be positioned adjacent each of the inlets; and a venturi used for increasing airflow to the fan. In addition the air tunnels can each include a plenum for directing air from the inlet to the pair of opposed heat sinks.

In an especially preferred embodiment, each air tunnel includes a splitter downstream of the first pair of heat sinks for splitting the air tunnel into first and second branches, wherein each of the first and second branches is at least partially defined by pairs of opposed heat sinks, wherein each of the heat sinks defining the first and second branches comprises fins extending into the interior of the branches and the interior of the branches is isolated from the electronic components. The air tunnel can also include a collector, which directs airflow to the outlet.

The amplifier housing preferably includes front and rear panels having the outlets and inlets of the tunnels defined therein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described in greater detail. Like or similar reference numerals will be used whenever possible, although, for the sake clarity, not all reference numbers are shown in each drawing. The heat dissipation system of the present invention will be described in terms of inclusion in an audio amplifier; such is for convenience only. It will be understood that the inventive cooling system can be applied to any electronic apparatus having the same requirements. Likewise, the invention will be described with respect to a specific orientation and relationship of elements with respect to each other, but it will be recognized by the skilled artisan that other orientations and relationships will be equally applicable.

Referring now to the drawings, and particularly toFIGS. 1-5, the amplifier apparatus of the present invention is shown and generally designated by the numeral10. The amplifier10includes a housing12, which is advantageously made up of a top-housing shell14, a bottom-housing shell16, a front panel18, and a rear panel20.

A plurality of printed circuit boards and the like, such as22and24are mounted within the housing. On each circuit board there are a plurality of electronic components such as26,28,30and32. Electronic components26,28,30and32are in operative contact with heat sinks so that heat generated by the electronic components is carried away from the components by the heat sinks in order to cool the electronic components. Although direct physical connection between the heat sinks and electronic components26,28,30and32is preferred, intermediate apparatus such as thermal interfaces, heat pipes, cooling plates, etc., may be employed. InFIG. 1there is a first pair of opposed heat sinks34A and34B, a second pair of opposed heat sinks36A and36B, and a third pair of opposed heat sinks38A and38B.

An enclosed cooling tunnel system40is defined within the housing12, cooling tunnel40at least partially defined by the space between opposed heat sinks34A and34B.

In the rear view ofFIG. 3, the inlet42of cooling tunnel40is shown. In the front view ofFIG. 2, the outlet44of cooling tunnel system40is shown. The various components, which make up the preferred embodiments of cooling tunnel system40, will now be described, starting at the inlet42and moving to the outlet44.

Defined in the rear panel20of housing12is a venturi46, which defines the inlet42. As used herein, the term “venturi” refers to a tapered housing surrounding the inlet so that an increased amount of air will be drawn through the inlet as contrasted to a simple opening cut in a flat housing wall. The venturi46funnels accelerated air into the cooling channel40.

The venturi46leads to a fan shroud48within which is mounted a fan49for drawing air through the inlet42. The fan shroud48may be a part of the fan assembly itself. There may also be a mesh screen fitted in between the inside face of the venturi46and the fan shroud48.

As best seen inFIG. 2, the fan shroud48is connected to a plenum50which leads to a portion of the cooling tunnel system, which is partially defined by the first pair of opposed heat sinks34A and34B.

As can be seen inFIG. 1, each of the heat sinks34A and34B includes a plurality of fins such as52. In this embodiment, the pair of heat sinks34A and34B are resting upon the printed circuit board22with their fins52pointing toward each other. Heat sinks34A and34B are in operative contact with electronic components26,28,30and32arrayed on printed circuit board22. Most preferably such contact is direct physical contact, or with a thermal interface (not shown) or the like interposed therebetween.

A sealing strip54closes the gap between heat sinks34A and34B from above, so as to define a portion of the cooling tunnel between the printed circuit board22on bottom, the heat sinks34A and34B on the sides and the sealing strip54on the top, which portion is in air flow communication with the plenum50as best seen in FIG.2.

A downstream end54of the just described portion of the cooling tunnel40is communicated with a splitter56, which may also be described as a diverging air tunnel shroud56. The splitter56, which can be described as being downstream of the first pair of heat sinks34A and34B, splits the air tunnel into first and second branches58and60.

First branch58leads to a portion of the air tunnel which is partially defined by the second pair of heat sinks36A and36B, and the second branch60leads to a branch of the air tunnel which is partially defined by the third pair of heat sinks38A and38B in a manner similar to that previously described for the first pair of heat sinks34A and34B. Each pair of heat sinks34A and B, and36A and B has the gap therebetween sealed by a sealing strip39.

An exhaust collector62, which may also be described as a converging air tunnel shroud62, receives the air from branches58and60after it is passed between the pairs of opposed heat sinks36A and36B, and38A and38B, and carries the air to the outlet44which is preferably covered by a grill mesh64or the like.

Thus, it is seen that the cooling tunnel system40provides a completely enclosed air tunnel leading from the inlet42to the outlet44. The air passing through tunnel40passes over the fins such as52of the heat sinks34A and34B,36A and36B and38A and38B, but that cooling air is completely isolated from the electronic components such as26,28,30and32. Thus, the electronic components themselves are not exposed to dust or other particulate matter carried by the cooling air, and are also isolated from any noise generated by fan49.

As previously noted, inFIGS. 1-3only approximately one half of the electronics of the amplifier10are shown and this is the half that is located on what can be referred to as the left hand side of housing12. The right hand side of the housing12would also include additional circuit boards and components, and a second essentially identical cooling tunnel leading from a second inlet66to a second outlet68within the housing12.

As best seen inFIG. 3, each of the inlets42and66has an aerodynamic nose cone such as70centrally located in the inlet and facing outward of the inlet. The nose cone70is integrally molded as a portion of the rear housing panel20and is structurally held in place at an axial central location of the inlet42by spars72and74which extend to the wall of venturi46.

As is best seen in the schematic view ofFIG. 6, the fan49includes a motor76having a fan shaft78, which carries fan blade80. The fan shaft78is axially located within the fan shroud48and is sheltered from air flow82entering inlet42by the aerodynamic shaped nose cone70. The fan motor76is also sheltered. The aerodynamic shape of nose cone70minimizes turbulence of the airflow82entering inlet42. The diameter of nose cone70is preferably approximately the same as the diameter of the exterior of the fan motor76.

It is noted that the completely enclosed nature of the cooling tunnel system40, which isolates dust from the electronic components such as26,28,30and32, actually provides a system wherein it is not necessary to filter the air flowing therethrough, because dust from the air is not in contact with the sensitive electronic components26,28,30and32. In a preferred embodiment of the invention, however, as schematically illustrated inFIG. 7, a removable air filter82is received across the inlet42and is accessible from outside the housing12for replacement of the air filter82.

As seen inFIGS. 7 and 8, the air filter82may be formed from two resilient plastic inner and outer rings84and86with an annular foam type filter element88held therebetween. The inner ring84fits closely over nose cone70and the outer ring86fits closely within venturi46and may be held in place therein by protruding retaining bumps90and92, or similar retaining detail, defined in the venturi46.

Thus, the air filter element82can be removed by grasping the same from the exterior of the housing42and pulling it out of the venturi46, and similarly, a replacement air filter can be inserted back into place.

The foam air filter element88also serves as a sound damping element to reduce the audibility of noise from fan49to the user.

All cited patents and publications referred to in this application are incorporated by reference.

The invention thus being described, it will be apparent that it may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention and all such modifications as would be apparent as one skilled in the art are intended to be included within the scope of the following claims.