Patent Application
20050250632
The present application claims priority under 35 U.S.C. § 119 of German Patent Application No. 10 2004 022 3777, filed on May 6, 2004, the disclosure of which is expressly incorporated by reference herin in their entireties.
1. Field of the Invention
The invention relates to a controlled deflection roll having a revolving roll shell, a yoke which passes axially through the roll shell and is fixed against rotation, and at least one source of support arranged between the yoke and the roll shell.
2. Discussion of the Background Information
The regulation of the pressure of controlled deflection rolls is carried out by means of hydraulic valves, of which a large number of circuit variants exist. These include, inter alia, the variants in which the relevant pressure regulating valves are integrated in the interior of the roll. In contrast with positioning outside the roll, a design of this type has special advantages in the event of dynamic problems during the pressure regulation, since the line lengths between the sources of support and the valves can be minimized. Nevertheless, this design has been implemented only rarely in the past, which can be attributed to the fact that the maintenance of such systems appears to be too complicated and the technology appears to be too temperamental. For example, in the event of a valve failure, the entire roll would have to be dismantled.
The present invention provides an imporved controlled deflection roll an improved controlled deflection roll in which the aforementioned problems are eliminated.
According to the present invention, the source of support is at least partly operated with an electrorheological fluid (ERF) and/or ferrofluid, of which the viscosity can be varied via an electric or magnetic field.
According to the present invention, use is therefore made of the flow characteristics or viscosity of an electrorheological fluid or ferrofluid change under the influence of an electric or magnetic field, for example, a hydraulic pressure or a volume flow can be varied by changing the relevant field.
Under the influence of the relevant field, the flow characteristics of the electrorheological fluids (ERF) or ferrofluids can be adjusted continuously and reversibly. The ER fluids which are available are in particular silicone oil in which polyurethane particles are dispersed. With increasing electrical voltage or field strength, the apparent viscosity of the ERF in the field increases and the volume flow decreases. The characteristics of an electrorheologigal fluid (ERF) or ferrofluid therefore permit, for example, regulation of the pressure of the sources of support which is relatively simple, fast and extremely fail-safe. In addition, specific damping properties of the source of support can specifically be implemented, or the oscillatory behavior of the roll shell can be influenced in a specific manner.
Utilizing the field that influences the viscosity of the electrorheological fluid (ERF) or ferrofluid, for example the hydraulic pressure can therefore be varied appropriately. In particular, it is therefore possible to vary the pressure in the pressure chamber of a respective source of support. In this example, pressure regulation can be provided.
The volume flow can also be varied utilizing the field that influences the viscosity of the electrorheological fluid (ERF) or ferrofluid. In this example, volume flow regulation can be provided.
Furthermore, the damping characteristics of the source of support can also be varied utilizing the field that influences the viscosity of the electrorheological fluid (ERF) or ferrofluid.
In another embodiment of the controlled deflection roll according to the present invention, the oscillatory characteristics of the roll shell can be varied appropriately utilizing the field that influences the viscosity of the electrorheological fluid or ferrofluid and the corresponding changes in the pressure chamber of the source of support.
Designs of the controlled deflection roll in which the source of support is operated exclusively with the electrorheological fluid or ferrofluid are possible.
In this example, a plurality of sources of support can be supplied with the electrorheological fluid or ferrofluid via a common supply line, in which the system pressure (for example pump pressure) is maintained.
Between the pressure chamber of the respective source of support and the common supply line, a connecting line is preferably provided in each case, in which there is integrated a throttling point in which an electric conductor, cable or the like is arranged in order to produce the field.
A pressure sensor connecting directly to the pressure chamber of the source of support is advantageously provided. A pressure sensor of this type can then, for example, supply the actual pressure for regulating the hydraulic pressure under the source of support. In general, a commercially available pressure sensor can be used.
In the preferred embodiment, for the pressure regulation of a source of support, only the throttling point with insulated voltage connection, two cables or conductors and a pressure sensor are thus required in the interior of the roll.
Additionally, the electric controller provided for pressure regulation is preferably arranged outside the roll.
Since only one hydraulic feed line is required in the preferred embodiment, the mechanical construction of the roll system is simplified considerably. Thus, as compared with a conventional construction having a plurality of adjusting zones, the following components can be dispensed with: hydraulic valves, feed lines, quick-action couplings, pipe bundles in the interior of the roll.
In the example of the present roll construction, a design with bearing points and gear mechanisms located on the outside should preferably be chosen since, under certain circumstances, no antifriction mounting and gear mechanisms can be lubricated with the polarizable solid particles (diameter about 5 μm) in the electrorheological fluid or ferrofluid. The hydrostatics cope with these particles, since the gaps are approximately 10 times larger.
Alternatively, however, the source of support can also be operated in a two-circuit system, in which the electrorheological fluid or ferrofluid is used only for the pressure regulation and the lubrication of the source of support is carried out with conventional oil. If a plurality of sources of support are provided, each source of support is preferably operated in the two-circuit system.
The ER fluid, which is currently still relatively expensive, is therefore used only for the pressure regulation in the present invention, which means that substantially less ER fluid is required. The lubrication of the hydrostatic source of support is carried out with conventional oil, for which the oil pockets of the source of support can be supplied with a constant volume flow. The latter is preferably produced by means of volume dividers which are connected downstream of the hydraulic pump. The supply of the head of the source of support, which can be moved relative to the yoke, can be provided via hose lines. Generally, any other desired design variants may be used. Likewise, a constant pressure in combination with upstream throttles can be used to supply the head of the source of support. In this example, however, the constant pressure must always be greater than the maximum possible pressure of the source of support in the piston chamber, that is to say the pressure chamber of the source of support.
For the regulation of the pressure in the pressure chamber of the source of support, the electrorheological fluid or ferrofluid must flow in a separate circuit, since only when a fluid is flowing is pressure regulation by viscosity change possible. For this reason, in the present invention, in each case a connecting line, in which a throttling point is integrated in order to maintain the pressure in the pressure chamber, is provided between the pressure chamber of a respective source of support and the tank of the ERF or ferrofluid supply.
The throttling point in the connecting line to the ERF or ferrofluid tank, required to maintain the pressure in the pressure chamber of the source of support, can be designed in a conventional way. Thus, for example, this throttling point can comprise an aperture stop or a capillary.
However, the throttling point can also be capable of control via an electric or magnetic field, and can in turn comprise an electric conductor, cable or the like for producing the field. Such a controlled variant has the advantage that the circulation volume flow of a respective source of support can be kept relatively constant irrespective of the pressure. In the case of the technically simpler variant mentioned previously, in which the throttling is carried out via capillaries or throttling points and in which the source of support is operated exclusively with the electrorheological fluid or ferrofluid, the circulating volume flow is approximately proportional to the piston pressure.
All the design variants permit very fast pressure regulation, since no connecting line is connected between the actuating element (a throttle which can be controlled electrically in the region of one millisecond by means of viscosity change) and the pressure chamber of the source of support. In the case of an oscillating roll shell, the pressure change can be regulated so quickly that it is possible to exert an active influence on the oscillation.
As already mentioned, the ERF or ferrofluid effect can also be used to specifically increase the damping characteristics of a respective source of support. For example, by connecting a voltage to the guide bush of a respective source of support, the viscosity of the fluid between the guide bush and the yoke can be highly increased locally, which leads to a considerable increase in the viscous damping of a source of support moved relative to the yoke. The guide bush in this case should be insulated electrically with respect to the head of the source of support, since otherwise, in the event of mixed friction of the head of the source of support on the rotating roll shell, it is possible for a voltage drop, or short circuit, to occur. These damping characteristics can likewise be influenced or regulated actively.
In another embodiment of the controlled deflection roll according to the invention, the source of support is assigned a damper, which is supported at one end on the head of the source of support and at the other end on the yoke and contains electrorheological fluid or ferrofluid, via the viscosity of which, which can be influenced by an appropriate field, the damping characteristics of the head of the source of support, which can be moved relative to the yoke, and/or the oscillatory characteristics of the roll shell can be varied.
In this embodiment, the damper can for example comprise a cylinder containing the electrorheological fluid or ferrofluid and a piston arranged in the cylinder, of which the external cross section is smaller than the internal cross section of the cylinder, so that in operation fluid displaced by the piston can pass through the radial region between the piston and the inner side of the cylinder. The respective field that influences the viscosity of the electrorheological fluid or ferrofluid can be produced in the radial region between the piston and the inner side of the cylinder.
The damper is expediently supported on the head of the source of support and on the yoke at one end via its cylinder and at the other end via a piston rod led to the outside from the interior of the cylinder, or vice versa.
The damper is preferably supported on the head of the source of support and on the yoke via a spherical joint in each case.
The damper can at least substantially be arranged within the pressure chamber of the source of support.
In another embodiment of the controlled deflection roll according to the invention, the source of support is designed as a ring element.
In this case, the internal space enclosed by the ring element is preferably connected to a discharge line in which a throttling point is integrated, which can be adjusted variably by the viscosity of an electrorheological fluid or ferrofluid flowing through this throttling point being variable via an electric or magnetic field. In this case, the throttling point can, for example, have an electric conductor which is arranged in the discharge line and through which the field can be produced.
In an the embodiment, the source of support has at least one annular pocket in its supporting face, the supporting face facing the surface of the shell and, facing the yoke, an annular pressure face which bounds a pressure chamber which is connected firstly to a pressure medium feed line and secondly via a throttle to the pocket.
In this example, a throttling point is advantageously integrated in the pressure medium feed line and can be adjusted variably by the viscosity of an electrorheological fluid or ferrofluid flowing through this throttling point being variable via an electric or magnetic field. The throttling point can, for example, comprise an electric conductor which is arranged in the pressure medium feed line and via which the field can be produced.
The annular pocket is expediently subdivided by transverse webs and each pocket section is connected to the pressure chamber via a throttle.
A pressure sensor connected directly to the pressure chamber of the source of support is advantageously provided.
A pressure sensor connected directly to the internal space can also expediently be provided.
The ring element forming the source of support can in particular be designed and operated in the manner as described in the documents DE 44 29 499 C1 and DE 195 40 791 C1.
While the viscosity of a respective electrorheological fluid can generally be varied via an electric field or an electric voltage, in the ferrofluids which can likewise be used the viscosity can be varied by connecting an appropriate magnetic field.
The invention will be explained in more detail in the following text using exemplary embodiments and with reference to the accompanying drawing.
The present invention is further described in the detialed description which follows, in reference to the noted drawing by way of non-limiting example of exemplary embodiment of the present invention, and wherein:
The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice.
The source of support 16 is operated with an electrorheological fluid (ERF) or ferrofluid, of which the viscosity can be varied via an electric or magnetic field.
Use of the field that influences the viscosity of the electrorheological fluid (ERF) or ferrofluid, the hydraulic pressure in particular can be varied, making it possible to regulate the pressure. A plurality, preferably all, of the sources of support 16 are supplied with the electrorheological fluid (ERF) or ferrofluid via a common supply line 18, in which the system pressure, for example pump pressure, is maintained.
Between the pressure chamber 20 of a respective source of support 16 and the common supply line 18, a connecting line 22 is provided. Integrated into this connecting line 22 is a throttling point 24, in which an electric conductor 26, a coil or the like is arranged in order to produce the field.
In addition, a pressure sensor 28 connected directly to the pressure chamber 20 of the source of support 16 is provided.
The electric controller provided for the pressure regulation is preferably arranged outside the roll 10.
In the preferred embodiment, therefore, each source of support 16 is preferably operated exclusively with the electrorheological fluid (ERF) or ferrofluid. The pressure supply is provided by the common supply line 18 for all the sources of support or supporting elements 16, in which line the system pressure, for example pump pressure, is maintained. Integrated in the connecting line 22 to the pressure chamber 20 of a respective source of support 16 is a throttling point 24, in which the relevant field can be built up by means of the electric conductor 26, coil or the like. Here an electric field is produced or a voltage is applied, which means that here the viscosity of an electrorheological fluid (ERF) is influenced appropriately. As discussed, use can also be made of a ferrofluid, of which the viscosity can then be influenced appropriately via an appropriate magnetic field.
In order to regulate the hydraulic pressure under the source of support 16, the actual pressure is measured by the pressure sensor 28, which can be a commercially available pressure sensor. For the pressure regulation of a source of support 16, only the throttling point, for example with insulated voltage connection, two cables and a pressure sensor 28 are therefore required in the interior of the controlled deflection roll 10.
The electrorheological fluid (ERF) or ferrofluid, which is currently still relatively expensive, is therefore used primarily for the pressure regulation, which means that less ER fluid or ferrofluid is required. In order to lubricate the hydrostatic source of support 16, the oil pockets 30 of the source of support 16 are supplied with a constant volume flow. The latter is preferably produced by means of volume dividers which are connected downstream of the hydraulic pump. The supply of the head of the source of support, which can be moved relative to the yoke 14, can be provided via hose lines. Other design variants are also conceivable. Likewise, a constant pressure in combination with upstream throttles can be used to supply the head of the source of support. In this case, however the constant pressure must always be greater than the maximum possible pressure of the source of support in the pressure chamber 20 of the source of support 16.
For the pressure regulation in the pressure chamber 20 of the source of support 16, the fluid must flow in a separate circuit, since only when a fluid is flowing is pressure regulation by viscosity change possible. For this reason, in the present embodiment, in each case a connecting line 32, in which a throttling point 34 is integrated in order to maintain the pressure in the pressure chamber 20, is provided between the pressure chamber 20 of a respective source of support 16 and the tank of the ERF or ferrofluid supply.
The throttling point 34 that maintains the piston pressure in the connecting line 32 can be designed in a conventional way and, for example, can be formed by an aperture stop or capillary.
However, with respect to this throttling point 34 as well, in principle an electrically or magnetically controlled variant is also conceivable. A corresponding embodiment is reproduced in
Here, the viscous damping of the source of support, which is moved relative to the yoke 14, can be varied via the viscosity of the electrorheological fluid (ERF) or ferrofluid between the guide bush 36 of the source of support 16 and the yoke 14.
The ERF or ferrofluid effect can therefore be used to specifically increase the damping characteristics of the source of support 16. By connecting a voltage to the guide bush 36 of the source of support 16, the viscosity of the fluid between the guide bush 36 and the yoke 14 can be highly increased locally, which leads to a considerable increase in the viscous damping of the source of support 16 moved relative to the yoke 14.
The guide bush 36 in this case should be insulated electrically with respect to the head of the source of support, since otherwise, in the event of mixed friction of the head of the source of support on the rotating roll shell 12, it is possible for a voltage drop or short circuit to occur. These damping characteristics can likewise be regulated actively.
The damper 38 contains electrorheological fluid or ferrofluid, in which the viscosity can be influenced by an appropriate field, the damping characteristics of the head 16′ of the source of support, which can be moved relative to the yoke 14, and/or the oscillatory characteristics of the roll shell 12 can be varied. In the present exemplary embodiment, the damper 38 comprises a cylinder 40 containing the electrorheological fluid or ferrofluid and a piston 42 arranged in the cylinder 40. The external cross section of the piston 42 is smaller than the internal cross section of the cylinder 40, so that in operation fluid displaced by the piston 42 can pass through the radial region between the piston 42 and the inner side of the cylinder.
The respective field influencing the viscosity of the electrorheological fluid or ferrofluid is produced in the radial region between the piston 42 and the inner side of the cylinder. In this case, a voltage U can, for example, be applied between the piston 42 and the cylinder 38 in the manner illustrated in
The damper 38 is supported on the head 16′ of the source of support and on the yoke 14 at one end via its cylinder 40 and at the other end via a piston rod 44 led to the outside from the interior of the cylinder 40. In principle, an embodiment in which the damper 38 is supported on the head 16′ of the source of support via the piston rod and is supported on the yoke 14 via the cylinder 40 is also conceivable.
In the present exemplary embodiment, the damper 38 is supported on the head 16′ of the source of support and on the yoke 14 via a spherical joint 46 in each case.
As can be seen from
In this embodiment, the internal space 48 enclosed by the ring element is connected to a discharge line 50, in which a throttling point 52 is integrated. The throttling point can be variably adjusted by the viscosity of an electrorheological fluid or ferrofluid flowing through this throttling point 52 being variable due to an electric or magnetic field. The throttling point 52 comprises an electric conductor 26 which is arranged in the discharge line 50 and via which the field can be produced. For example, a voltage U2 can be applied to this conductor and can then be variably adjusted in an appropriate manner.
The source of support 16 has at least one annular pocket 58 in its supporting face 56 facing the inner surface 54 of the shell, and an annular pressure face 60 facing the yoke 14. The pressure face 60 bounds a pressure chamber 20, which is connected firstly to a pressure medium feed line 62 and secondly via a throttle 64 to the pocket 58.
Integrated in the pressure medium feed line 62 is a throttling point 66, which can be adjusted variably by the viscosity of an electrorheological fluid or ferrofluid flowing through this throttling point 66 being variable via an electric or magnetic field.
As can be seen from
By way of example, a voltage U1 which can be varied appropriately can be applied to the electric conductor 68.
The annular pocket 58 is expediently subdivided by transverse webs. In this case each pocket section can be connected to the pressure chamber 20 via a throttle 64.
Additionally, the present exemplary embodiment provides a pressure sensor 70 connected directly to the pressure chamber 20 of the source of support 16.
Additionally, the ring element forming the source of support 16 can be designed and operated in the manner as described in the documents DE 44 29 499 C1 and DE 195 40 791 C1.
It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in now ay to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, withour departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to paticular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.
Voith Paper Patent GmbH V 10016PEP—Ku/ho
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 022 377.7 | May 2004 | DE | national |
