Abstract:
An installation piece for supporting a roller in a roller stand of a roller frame. The installation piece includes a main bore for receiving a journal of the roller, an inlet for a lubricant, an outlet for the lubricant, and a pump device for pumping the lubricant leaving the installation piece through the outlet. The pump device has a housing, an inlet channel, and an outlet channel. The inlet channel communicates with the inlet and the outlet channel communicates with the outlet for the flow of the lubricant. The pump device is driven by the flow of the lubricant in the inlet. The housing of the pump device is equipped with a screw pump and a turbine, which is driven by the pressurized inflowing lubricant, in the inlet channel for driving the screw pump.

Description:
The present application is a 371 of International application PCT/EP2013/077091, filed Dec. 18, 2013, which claims priority of DE 10 2012 224 511.1, filed Dec. 28, 2012, the priority of these applications is hereby claimed and these applications are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The invention pertains to an installation piece, i.e., a bearing housing for supporting a roll in a roll housing of a rolling stand. The rolling stand comprises a main bore to hold the journal of the roll. The installation piece comprises an inlet for supplying lubricant, typically under pressure, to the interior of the installation piece and an outlet for carrying the lubricant back out of the installation piece. The lubricant serves to lubricate the roll neck bearing during the rolling of stock such as slabs. 
     The installation piece can be provided with a pump device for conveying the lubricant flowing back from the installation piece through the return. Such a pump device will then comprise a housing, an inlet channel, and an outlet channel, wherein the inlet channel in the pump device communicates fluidically with the inlet in the installation piece, and the outlet channel in the pump device communicates fluidically with the outlet for the lubricant in the installation piece. The pump device can be driven by the flow of lubricant in the inlet. The basics of installation pieces of this type with pump devices for supporting the return flow of the lubricant are known in the prior art according to, for example, European patents EP 1 078 172 B1 and EP 1 497 048 B1 or according to the international patent application WO 03/090948 A2. 
     A wide variety of pump devices are also generally known from the prior art, such as circulation pumps, hydraulic power screws, and screw pumps as described in Wikipedia, for example. Screw tube conveyors, for example, are also known from U.S. Pat. No. 1,434,138 or from CH 95561. 
     SUMMARY OF THE INVENTION 
     The invention is based on the goal of providing an installation piece with an alternative pump device for supporting the return flow of lubricant from the installation piece. 
     This is characterized in that the pump device comprises, in its housing, a screw pump with a feed screw in the outlet channel for conveying the returning lubricant and, to drive the screw pump, a turbine in the inlet channel, which is driven by the lubricant arriving under pressure. 
     The inlet and the outlet—the outlet also being called the “return” in the following—are arranged in the installation piece. The inlet channel and the outlet channel—also called the “return channel” in the following—are arranged outside the installation piece in the pump device. The inlet is at least roughly aligned with the inlet channel at their connecting point. The outlet channel is at least roughly aligned with the outlet channel at their connecting point. 
     According to a first exemplary embodiment, the screw pump is formed by a tubular base body, which carries a feed screw on its outside surface; and the housing of the pump device comprises a bore, in which the screw pump is rotatably supported in bearings. The space between the outside surface of the base body and the inside surface of the bore forms the outlet channel, wherein the feed screw projects into the return channel to convey the returning lubricant, and wherein the bearings—and thus also the feed screw—are supported by retaining means in the interior of the bore in such a way that they remain in the same position but are free to rotate. 
     Each of the individual turns of the feed screw is advantageously arranged at an acute angle α—in the flow direction of the lubricant in the return—to the tubular base body. This angle advantageously increases the efficiency of the feed screw. 
     The retaining means for the bearings are, for example, configured as spoked wheels or perforated plates, each of which extends in a plane perpendicular to the longitudinal axis of the bore in the housing. At their periphery, they are connected to the housing at the inside surface of the bore. At their inside ends, each one carries—preferably coaxial to the bore—one of the bearings for the screw pump. 
     The configuration of the retaining means in the form of spoked wheels or perforated plates is quite necessary to keep the return channel open, at least below the longitudinal axis of the bore, for the flow of the lubricant. 
     The interior of the tubular base body forms the inlet channel. In this inlet channel, the turbine which drives the screw pump is arranged. This structural configuration according to the invention, in which the inlet channel is arranged in the center along the longitudinal axis and the return channel is arranged coaxially to the inlet channel, offers the advantage that the pump device can be built very compactly, that is, in a space-saving manner. 
     It is advantageous for the ratio of the cross-sectional area of the return channel to the cross-sectional area of the inlet channel to be in the range of 2-10. That the return channel must have a larger cross section than the inlet channel results simply from the fact that the lubricant is pumped under pressure into the inlet channel, whereas—at the same volume flow rate—it flows through the return channel merely at atmospheric pressure. 
     On the outlet side of the installation piece, the return emerges from the installation piece in the form of a single bore, and the single inlet is guided into the installation piece inside the bore for the return. The pump device is preferably a separate unit, which is set externally onto the outlet side of the installation piece in such a way that the inlet channel of the pump device communicates fluidically with the inlet of the installation piece, and the return channel of the pump device communicates fluidically with the return of the installation piece. 
     The outlet side of the installation piece is the side which is opposite the barrel side of the installation piece. The barrel side of the installation piece is the side which directly faces the barrel of the roll after the roll has been installed. 
     According to another exemplary embodiment, the bore for the return on the outlet side of the installation piece is positioned with respect to the main bore which holds the neck of the roll in such a way that the upper vertex of the bore for the return comprises a vertical distance s of 0&lt;s&lt;r 1  from the lower vertex of the effective opening of the ring-shaped sealing lip arranged in the main bore, where r 1  is the radius of the bore for the return. The upper vertex of the bore for the return preferably lies above the lower vertex of the effective radius of the sealing lip. Between the center of the main bore and the center of the bore for the return, there is a horizontal distance d 1  of R 1 &lt;d 1 &lt;R 1 +100 mm, where R 1  is the effective radius of the ring-shaped sealing lip; it is somewhat smaller than the radius of the main bore. 
     The ring-shaped sealing lip is set onto the neck of the roll and seals the roll against the main bore of the installation piece. The effective opening of the sealing lip is to be understood as the opening which results when the sealing lip is under slight radial compression after the roll neck has been put in place. The radius of this effective opening is called the effective radius of the sealing lip. 
     The diameter of the bore for the return in the installation piece and of the bore for the return channel in the pump device is advantageously in the range of only 40-80 mm. 
     The installation piece can be an upper installation piece for supporting an upper back-up roll or a lower installation piece for supporting a lower back-up roll in the rolling stand. 
     Finally, it is advantageous for the bottom surface of the upper installation piece to be flat. The distance d 2  between the lower vertex UB of the main bore ( 110 ) and of the installation piece and the flat bottom surface of the upper installation piece is d 2 &lt;20 mm, preferably d 2 &lt;10 mm. 
     In general, the present invention offers the following advantages: 
     The pump device increases the volume flow rate of the lubricant in the outlet. This offers the advantages that, when installation pieces according to the invention are used, it is possible to select a smaller cross-sectional area or a smaller radius for the bore of the outlet in comparison to installation pieces without the pump device according to the invention. In particular, when the pump device according to the invention is used, it is possible to eliminate completely a second bore for the return of the lubricant as is typically used in traditional installation pieces; that is, when the pump device according to the invention is used, it is necessary to provide only a single bore for the outlet on the outlet side of the installation piece. 
     It is also possible, furthermore, especially when the claimed horizontal distance d 1  and the vertical distance s are respected, to adhere to a previously determined maximum distance between the lower vertex (UB) of the main bore ( 110 ) and the preferably flat bottom surface of the installation piece or to an even shorter distance. This in turn offers the advantage that the overall height of the installation piece can be kept comparatively low in comparison to traditional installation pieces, resulting in the advantage that more room is available in the window of the roll housing for the installation of other components such as bending cylinders. 
     A total of five figures is attached to the invention: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  shows a perspective view of the installation piece according to the invention; 
         FIG. 2  shows a longitudinal cross section through the installation piece with the pump device set in place; 
         FIG. 3  shows a longitudinal cross section through the pump device according to the invention; 
         FIG. 4  shows a schematic cross section through the outlet side of the installation piece; and 
         FIG. 5  shows a cross section through the pump device according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention in the form of exemplary embodiments is described in detail below on the basis of the attached figures. Technical elements which are the same are designated by the same reference numbers in all the figures. 
       FIG. 1  shows by way of example a perspective view of the installation piece  100  according to the invention, the view being directed toward its outlet side  105 . 
     An installation piece constitutes a bearing housing to hold the neck of a roll (not shown here). The installation piece is typically vertically movable in the window of a roll housing. In the installation piece, a main bore  110  is provided to hold the roll neck and preferably also a bearing bush and a neck bush, which, however, will not be discussed further here. When the roll or roll neck is supported in the bore of the installation piece, one side of the installation piece will be facing the barrel of the roll. This side of the installation piece is called the barrel side. The previously mentioned outlet side  105  of the installation piece is opposite the barrel side. The name comes from the fact that the lubricant, which is supplied on this side to the installation piece during operation, i.e., during the rotation of the roll, emerges from the barrel side and is carried away from there. 
     In  FIG. 1 , an inlet  120  can be seen, through which the lubricant  200  is introduced into the installation piece  100 , so that, via the inlet opening  120 - 1 , it can enter the intermediate space between the bore of the installation piece and the roll neck or, more precisely, into the intermediate space between a bearing bush and a neck bush, so that it can form a lubricating film there. During the operation of the roll, the lubricant is guided continuously around a circuit; that is, lubricant is supplied continuously under pressure via the inlet  120  and carried away from the outlet side. After it has been used in the intermediate space, the lubricant collects in the lower area of the installation piece on the barrel side and on the outlet side in a lubricant collection space  142  of the installation piece. From there, it is typically pumped away and returned to the lubricant circuit. The pump, which serves to maintain the lubricant circulation and which pumps the lubricant at a pressure p into the inlet  120 , is not an object of the invention and for this reason is not shown in the figures. The important point, however, is that this pump is not to be confused with the pump device  130 , which is the object of the invention. 
     In  FIG. 1 , the outer coaxial ring represents both the outlet  140  inside the installation piece and the outlet channel  136 , typically aligned with it, in the pump device according to the invention for carrying away the lubricant which has collected in the lubricant collection space  142 . 
     The vertical center plane LM of the main bore  110  is also indicated in  FIG. 1 . As already explained above at the end of the general part of the description, the pump device according to the invention to be described below makes it possible for the distance d 2  between the lower vertex UB of the main bore  110  and the preferably flat-configured bottom surface of the upper installation piece to be made comparatively short: The upper limit is at d 2 &lt;20 mm, and preferably d 2 &lt;10 mm. The lower limit, in contrast, is determined by safety considerations and/or by the necessary bearing load. 
       FIG. 2  shows a longitudinal cross section through the installation piece  100  with its outlet side  105  and the pump device  130 . It can be seen that the pump device  130  is set onto the outlet side  105  of the installation piece, and that the inlet  120  for the lubricant  200  in the interior of the installation piece  100  communicates fluidically with the inlet channel  134  in the interior of the pump device  130 . Similarly, the outlet  140  in the interior of the installation piece communicates fluidically with the outlet channel  136  inside the pump device. According to the invention, the inlet channel  134  and the outlet channel  136  are coaxial to each other. 
       FIG. 3  shows a longitudinal cross section through the pump device  130  according to the invention. The pump device has a housing  132 , in which a screw pump  137  is rotatably supported. A tubular base body  137 - 1  of the screw pump  137  is supported rotatably in bearings  137 - 2 . The bearings  137 - 2  and thus also the screw pump  137  supported therein are mounted in the interior of the housing  132  by means of the retaining means  132   a . The retaining means  132   a  are configured in the form of spoked wheels or perforated plates, for example. Each of the retaining means preferably extends in a plane perpendicular to the longitudinal axis L of the bore in the housing  132 . At their periphery, the retaining means are connected, possibly integrally, to the housing  132  at the inside surface of the bore. 
     The tubular base body  137 - 1  of the screw pump  137  carries on its outside surface a feed screw  138 . The turns of the feed screw  138  project into the intermediate space between the outside surface of the tubular base body  137 - 1  of the screw pump  137  and the inside surface of the bore in the housing  132 , wherein this intermediate space forms the outlet channel  136  for the lubricant  200 . The turns of the feed screw are set at an angle α, in the flow direction, to the outside surface of the tubular base body  137 - 1 . The flow direction of the lubricant  200  supplied through the inlet channel  134  and leaving the lubricant collection space  142  is indicated by the arrows in  FIG. 3 . 
     The outlet channel  136  is coaxial to an inlet channel  134 , which is formed by the interior of the tubular base body  137 . In the interior of the tubular base body, there is a turbine  139 , which is connected nonrotatably by its outside surface to the tubular base body  137 - 1 . The turbine  139  is driven by the pressurized lubricant which the circulation pump (not shown here) supplies via the inlet channel  134 ; in  FIG. 3 , the lubricant flows through the inlet channel  134  from right to left. It is advantageous that the turbine therefore does not require its own independent drive device or any external or additional energy input. The turbine drives the screw pump  137  as a result of its permanent connection to the tubular base body  137 - 1  and in this way causes the feed screw  138  to rotate. Because this feed screw  138 , as previously mentioned, projects into the lubricant  200  present in the outlet channel  136 , the rotation of the feed screw  138  supports the desired outflow of the lubricant  200  from the lubricant collection space  142 . After the incoming lubricant has passed by the turbine in the interior of the inlet channel  134 , it enters the lubricant inlet  120  present in the interior of the installation piece, so that it can be fed via the inlet opening  120 - 1  into the intermediate space between the roll neck and the bore of the installation piece, i.e., between the neck bush and the bearing bush. 
     At point “A”, a sealing device according to the prior art is arranged. 
       FIG. 4  shows a cross section through the outlet side of the installation piece  100 . The cross section is shown only in highly schematic fashion. It serves to illustrate the structural relationships essential to the present invention. 
     First, it is important to position the center point or longitudinal axis of the pump device  130  according to the invention in relation to the lubricant collection space  142  in such a way that, during operation of the roll, the maximum level PH of the lubricant  200  in the interior of the lubricant collection space  142  does not rise above the center axis or longitudinal axis L of the pump device  130 . At the same time, the level of the lubricant  200 , e.g., oil, in the return channel should not fall below the lower vertex of the turns of the feed screw during operation. It is also important for the upper vertex OS of the bore for the outlet  140  always to be above, in the vertical direction, the lower vertex US of the effective opening of a ring-shaped sealing lip arranged in the main bore  110 . The distance should preferably be greater than 0 and less than the radius r 1  of the bore for the outlet  140 . In addition, for the horizontal distance d 1  between the center of the main bore  110  and the center of the bore for the outlet  140 , it should be true that R 1 &lt;d 1 &lt;R 1 +100 mm, wherein R 1  is the effective radius of the ring-shaped sealing lip. 
     To explain the term “effective radius”: Before the roll neck has been introduced into the bore  100 , the sealing lip is not under any load; that is, its inside radius has the minimum value. After the roll neck has been introduced into the bore, however, the sealing lip rests against the roll neck and is thus compressed slightly in the radial direction. This radial compression brings about a slight increase in the inside radius of the sealing lip; the radius of the sealing lip thus obtained is called the “effective radius”. 
       FIG. 5  shows a cross section through the pump device  130  according to the invention. The outer shaded area shows the pump housing  132  with a circular or cylindrical bore, in which the screw pump  137  is mounted. It is possible to see the tubular base body  137 - 1 , which is coaxial to the bore in the housing  132 . In the interior of the tubular base body  137 - 1 , the turbine  139  with its impellers is illustrated schematically. The internal cross section of the tubular base body represents the cross-sectional area A 2  of the inlet channel  134 . 
     The outside space between the outside surface of the ring-shaped base body  137 - 1  and the inside surface of the bore  133  in the interior of the housing  132  represents, as already explained above, the outlet channel  136 . The cross-sectional area of this coaxial annular space represents the cross-sectional area A 1  of the outlet channel. Because the lubricant is supplied under pressure p through the inlet channel  134  and the inlet  120  into the installation piece and is carried away through the outlet channel  136  only at atmospheric pressure, the cross-sectional area of the inlet channel  134  can be considerably smaller than the cross-sectional area of the outlet channel  136 . The ratio of cross-sectional area A 1  of the outlet channel to the cross-sectional area A 2  of the inlet channel is typically in the range of 2-10. This ratio is made possible primarily by the pump device  130  according to the invention, which allows the more rapid removal of the lubricant  200  from the lubricant collection space  142  under atmospheric pressure. 
     As previously mentioned, the pump device  130  makes it possible to eliminate a second outlet bore on the outlet side of the installation piece. In addition, the radius r 1  of the bore  133  in the housing  132  of the pump device or of the outlet channel  136  can be kept so small that the structural distance ratios described above with reference to  FIG. 4  can be easily maintained. 
     Finally,  FIG. 5  shows the spoke-like structure of the retaining means  132   a . This structure of the retaining means in the form of spoked wheels or perforated plates is necessary so that the lubricant can flow through the pump device and in particular flow through the outlet channel  136 . 
     LIST OF REFERENCE SYMBOLS 
     
         
           100  installation piece 
           105  outlet side 
           110  main bore 
           120  inlet 
           120 - 1  inlet opening 
           130  pump device 
           132  housing 
           132   a  retaining means 
           133  bore 
           134  inlet channel 
           136  outlet channel 
           137  screw pump 
           137 - 1  tubular base body 
           137 - 2  bearing 
           138  feed screw 
           139  turbine 
           140  outlet 
           142  lubricant collection space 
           200  lubricant 
         A 1  cross-sectional area, outlet channel 
         A 2  cross-sectional area, inlet channel 
         OS upper vertex of the outlet bore 
         US lower vertex of the effective diameter of the ring seal 
         UB lower vertex of the main bore 
         R 1  effective radius of the ring-shaped sealing lip 
         r 1  radius of the bore for the outlet 
         d 1  horizontal distance between the center of the main bore and the center of the bore for the outlet 
         d 2  distance between the lower vertex (UB) of the main bore ( 110 ) of the installation piece and the bottom surface of the upper installation piece 
         L longitudinal axis (L) of the bore ( 133 ) in the housing 
         LM vertical central plane of the main bore 
         s distance 
         PH oil level in the lubricant collection space ( 142 )