Piston actuated rotary union

#The present invention relates to fluid coupling devices such as rotary unions and, more particularly, to an improved seal control actuator mechanism that operates with fluid pressure regardless of the use of lubricating media, non-lubricating media, or no media within the rotary union.

#Fluid coupling devices such as rotary unions are used in industrial applications, for example, machining of metals or plastics, work holding, printing, plastic film manufacture, papermaking, semiconductor wafer manufacture, and other industrial processes that require a fluid medium to be transferred from a stationary source such as a pump or reservoir into a rotating element such as a machine tool spindle, work-piece clamping system, or rotating drums or cylinder. Often these applications require relatively high media pressures, flow rates, or high machine tool rotational speeds.

#Rotary unions used in such applications convey fluid medium used by the equipment for cooling, heating, or for actuating one or more rotating elements. Typical fluid media include water-based liquids, hydraulic or cooling oils, and air. In certain instances, for example, when evacuating media from a fluid passage, rotary unions may operate under vacuum. Machines using rotary unions typically include precision components, such as bearings, gears, electrical components, and others, that are expensive and/or difficult to repair or replace during service. These components are often subject to corrosive environments or to damage if exposed to fluid leaking or venting from the rotary union during operation.

#FIG. 1 is a front view of a non-rotating portion of one embodiment of a rotary union in accordance with the disclosure.

#FIGS. 2, 3 and 7 are cross sections of the embodiment of a rotary union shown in FIG. 1 in two operating positions.

#FIGS. 4 and 5 are cross sections of a second embodiment of a rotary union in two operating positions.

#In the drawings, which form a part of this specification, FIG. 1 is a front view of a non-rotating portion 101 of the rotary union 100. FIGS. 2 and 3 are cross sections of the rotary union 100 in two operating positions. In reference to FIGS. 1-3, the rotary union 100 includes a rotating seal member 102 connected to the end of a rotating seal carrier 103, which is commonly referred to as a rotor, and a non-rotating seal member 104 that is connected at the end of a non-rotating seal carrier 105. The non-rotating seal carrier 105 is axially moveable relative to a housing 106, which is best shown in FIGS. 2 and 3. Although the housing 106 is shown as a two-piece construction in FIGS. 2 and 3, a single piece construction, or a construction of more than two pieces may be used as desired for the housing 106. In the present disclosure, the housing 106 is referred to as a single structure without regard to the number of pieces that make up its construction. The rotating seal member 102 is associated with a rotating machine component (not shown) such as a machine spindle, as is known. The housing 106 is associated with a non-rotating machine component (not shown). A segmented conduit or media channel 112 extends through the rotating seal carrier 103, the non-rotating seal carrier 105, and the rotating and non-rotating seal members 102 and 104 respectively, as best illustrated in FIGS. 2 and 3.

#Portions of the media channel 112 are defined in different components of the rotary union 100 to provide a fluid passageway through the rotating and non-rotating carriers 103 and 105 when the rotating and non-rotating seal members 102 and 104 are engaged. The media channel 112 may be selectively arranged to sealingly enclose fluids when the rotating and non-rotating seal members 102 and 104 are engaged to one another, and be open for venting to the atmosphere when the rotating and non-rotating seal members 102 and 104 are not engaged, as is described in more detail relative to the operation of the rotary union 100 and the description that follows relative to the flowchart of FIG. 6, described below. In certain applications, the media channel 112 may be subjected to a vacuum that pulls and evacuates working fluids from within the media channel 112.

#The rotating seal carrier 103, which can be connected or associated with any type of machine component such as a spindle on a CNC milling machine, supports the rotating seal member 102. A mechanical face seal is created when the rotating seal member 102 is engaged with the non-rotating seal member 104. The mechanical face seal operates to seal the media channel 112 for transferring a fluid medium from the rotating to the non-rotating seal carriers 103 and 105 and, thus, through corresponding machine components to which the carriers are connected. In the illustrated embodiment, the housing 106 is connectable to a non-rotating portion or component of a machine by bolts (four shown) extending through bolt holes 109 to engage corresponding threaded openings formed in the non-rotating machine component, but other mounting arrangements can be used.