FI119480B - Method and apparatus for removing the zero load in a bearing - Google Patents

Description

119480

The present invention relates to a method for removing a zero bearing of a rolling bearing, such as a roller, needle or ball bearing, comprising fixed rolling members.

The invention also relates to an arrangement for carrying out the method.

10

In the manufacture of paper, board and other fibrous webs, various nip rolls are used during manufacture to, among other things, dewater, apply treatment agents, and smooth and polish the surface of the product. The largest clamping forces occur on calendars and dewatering presses. The nip load between the rollers is controlled by compression by various actuators, and in some cases it is possible that the forces exerted on the roller are so balanced that the bearings 20 supporting it are not subjected to any load at all and so-called. zero load area. By this, we mean a · V · lawful bearing load condition where the load on its rolling members is too small to cause • t · • 1, · rolling contact and the bearing begins to slide. A zero load is damaging to the bearings, as sliding contact consumes the rollers of the ·· • 1 · bearings rather quickly. Bearing ready • 1 · S ... you recommend a load of 1-2% of bearing capacity to eliminate the zero load problem.

• · • 1 f • · · · 30 In most cases, there is a risk of falling into the zero load range. Lantern. Load on calender end roller bearings • · · • 1 h ···. varies with calender driving conditions. Adjustment of the line load on the calender affects the load on the roller bearings 1: 1. When the • · 2 119480 gravitational force in the vertical bogie is balanced with the bottom lifting nip force, no load is applied to the bearings. Likewise, if the roll is subjected to a line load on both sides, a situation may arise in which the nip forces of different directions and the force of the roll mass 5 are balanced. Roller bearings require a certain amount of load to prevent the rollers or balls in the bearing from rotating and not sliding. In the zero-load situation described above, this load criterion is not met.

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In the multi-roll calender, zero load occurs in the so-called. partial nip, so only two or three rollers work together. The problem also occurs with soft calendars. In order to eliminate the zero load problem, a restriction has been made on the calender line load adjustment range 15. With the vertical soft and multi-roll calender, the minimum load recommended by the bearing manufacturers significantly reduces the line loading space available on the calender, especially for matte grades. The linear loading range of a partial nip run of a multi roll calender, typically 20 ... 100 kN / m, may have a limited operating range due to the zero load problem. If the • · · V · process would otherwise work best in this area, this is a serious problem.

Ij *: 25 A zero load has been used to eliminate or reduce the load! * \. traditionally e.g. the following means: ***: - The rack may be slanted so that the load ··· horizontal force component creates the required minimum load on the bearings, such a solution is presented by · ·; ***: 30 in WO 2006/051169, ·· - Axial loading device bearing outer ring - \\ Y US 6, 158,897, • · • «*! * - Coating bearings to withstand zero load situations - ♦ · • · ·, ♦ · 3 119480 - Prevents calendar loading in zero load area - Provides bearing force through it with flowing oil - US 4,322,117.

5 Installing the track on a skewed calender requires redesign of the entire track and equipment placement. Thus, this solution is at least not suitable for use in existing calendars. If you want to stay in a vertical calender for other reasons, skewing is not a good option as it will result in expensive roller feeders. The axial loading device has been tested in soft calendars. The device does not completely eliminate the problem with, among other things, the double row spherical roller bearings, as it only loads one of the roller rings, which further reduces the load on the rin-15 toothy ring. Bearing retreading is an option to reduce the problem of zero loading. However, it does not completely remove it. In addition, the coating is expensive and its functionality is highly dependent on the lubrication conditions. Due to replaceable rolls, all rolls should be equipped with expensive coated bearings. The zero load can be set to a continuous ··· V · lifetime of the entire bearing, or it can be load dependent, intermittent or otherwise adjustable.

It is an object of the present invention to provide a method and an ··· 1 ·· arrangement for reducing or even eliminating a zero load problem with fiber web machines.

The invention is based on the fact that the outer circumference ···. V of a rolling bearing fitted with a shaft: is directly loaded by at least one load device and * · 1 1, ···. at least periodically in a direction transverse to the axis.

• · • · · • · · ·· «t · 4 119480

According to a preferred embodiment of the invention, the bearing outer circumference is loaded with a screw pressed onto the bearing outer circumference.

According to one preferred embodiment, the bearing outer periphery is loaded with fluid pressure.

According to a further embodiment, more than one load force is applied.

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According to one embodiment, the loading force is arranged at an angle of 75 to 105 °, preferably 90 °, with respect to the vertical loading force, i.e. the loading force and the gravity of the nip.

15

According to a particularly preferred embodiment, the bearing outer circumference is loaded against the nip load in the transverse direction.

More specifically, the method of the invention ... and the arrangement are characterized by what is presented by themselves · · · • · t *. in the character sections of these requirements.

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; ; Preferred embodiments of the invention are defined more precisely in the dependent claims.

The invention provides considerable advantages.

The invention allows the elimination of conductive bearing damage from the zero load problem. Equipment utilization improves and unpredictable production disruptions are reduced. The installation of the device is easy and reasonably priced and

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; available on existing devices. • · • "No effect on calender operation other than removing • 5 119480 harmful area restriction. With no area restriction, the machine operator can better optimize its production, for example to produce the best quality. The device has the advantage of being simple and cool. Changes in bearing structure and bearings required by the invention are generally minor and can be made in principle to any bearing structure.The cost of the bearing and bearing housings does not increase substantially and the cost of the necessary modifications 10 compared to existing structures can be quickly saved.

The invention will now be explained in more detail with reference to the accompanying drawings.

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Figure 1 is a side elevational diagram of the invention.

Fig. 2 is a sectional view of one embodiment of the invention.

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Figure 3 is a schematic view of another embodiment of the invention.

Figure 4 is a schematic view of a fourth embodiment of the invention.

• »Ϊ · * · 25 • · · ^ ^ · * · · i \. Figure 1 schematically illustrates the nipples of two superimposed * rolls 1, 2. At the nip point of the rolls 1, 2, there is an effect of a · · · nip load FN, which is the forces and forces on the nip. and related bearings and accessories • · · ***. 30 weight force. In certain situations, these forces cancel each other out, so that the roller bearings 3 do not need to carry the load and rotate unloaded. The disadvantages of this situation are shown above. The main rollers of the rollers 1, 2 have axles 5 fitted with rolling bearings • · 6 119480 3. The bearings are located in the bearing housing 4. In Figure 1, For simplicity, the bearing 3 and the bearing housing 4 of only one roller 1 are provided. The bearing 3 itself consists of an inner periphery 6 surrounding the shaft 5, an outer periphery 7 supported on the bearing housing 5 and a rolling member 8 disposed therebetween. In this case, the zero load discharge member is a screw 9, 10 inserted into a threaded hole in the bearing housing 4 to form a load F0 on the outer circumference of the bearing 3. The bearing 3 is supported on the bearing housing 4 by the cover flanges 10, 11 and the support rings 12, 13.

One embodiment of the invention is illustrated in more detail in Figure 15. In this embodiment, both inner and outer ring 6 and outer ring 7 of bearing 3 are disposed substantially free of shaft 5 and bearing housing 4. The loading screw 9 is positioned 90 ° to nip load FN and center 3 of bearing 3. is directed to the center of the rolling members 20, facilitating deformation of the outer ring 7. In this embodiment, the zero load is removed by providing the screw i; *: 9 with sufficient deformation on the outer circumference of the bearing 3 such that a load of at least zero load is applied to the rolling members 6 at least. The advantage of this embodiment is its extreme simplicity 25 · .. 25, all that is needed is a screw hole in the medicament: *** · throat and a screw 9 fitted thereto, with possible locking · ♦ · nuts or the like. The load force F0 is achieved by simply * turning the screw 9 by hand. A disadvantage of the solution may be that the outer circumference 6 is subjected to deformation, which can strain the bearing and cause • · · * · · ** wear and uneven running. The load screw 9 can easily be fitted with an actuator for automatic operation or remote control. Thus • · load F0 can only be set when necessary or the load may be intermittently varied to avoid static loading.

Figure 3 shows an alternative embodiment which requires a slight change in the structure of the bearing housing 3. Therein, a clearance 14 is formed on the opposite side of the loading screw 9 to allow a slight displacement of the bearing 3 in the loading direction of the loading screw 9, whereby the outer periphery 6 is loaded according to the force applied on the screw 9 side. The clearance does not need to be large, it is sufficient that it is greater than the inside clearance of the bearing in order for the bearing to be loaded by the force applied to the side opposite to the clearance. Since then the shaft and its bearings would also move in the bearing housing 4 pushed by the screws 15 9, the counter load F0f applied to the zero load discharge load F0 holds the bearing in place. For this purpose, a support bearing 15 is provided on the shaft 5, which receives the force exerted by the loading screw 9. The support bearing 15 is smaller than the main bearing 3 and is inserted into the housing 20 of the bearing 20 by means of a sleeve 16.

«·· ♦ · ♦ • · · j. *. Because the main bearing 3 must carry the load vertically, ··· {*. *. there must be no clearance in the bearing housing above and below the shaft 5 and bearing 3 • ·:. ·. Thus, the clearance 14 can extend only to narrow • M 9: ·. 25 less than a sector for the zero load discharge load Fo in both directions. A suitable range is from about 0.01 mm to about 2 mm.

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Fig. 4 otherwise shows a similar solution ♦ ·· * ... # su, but here there are two support bearings 15, i.e. bearings 15 · ** '30 on either side of the main bearing 3. Thus, the zero load removal * · i.i: load F0 is split between both support bearings in half 1 * 1 <Fo '/ 2).

9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 119480 In this case, the zero load protection load need not be taken into account when calculating the nip load. Of course, with the current computing capacity, adding a standard load to the nip load computing does not pose a problem.

However, the zero load shall not be parallel to, or at least slightly different from, the load.

10 In Fig. 1, the nip loads are denoted FN and the zero load restraint load F0. In addition, nip forces and bearing forces are, of course, influenced by the masses of the rollers. However, if the applied load force Fo is horizontal, i.e. at an angle of 90 ° to the vertical load, the calculation of nip loads can be maintained and the calender operation need not be interfered in this regard. The risk of a zero load usually only occurs in vertical load, but also in non-vertical load situations, the forces exerted on the bearing can be added together to create a zero load situation. The invention can be applied to:] Γϊ even in these cases. Further, although most advantageous,:: *: that the zero load compensation is perpendicular to the load ···: * · *; with respect to power, a slight deviation from this direction does not • • * add much to the nip load. For example, if a zero load with a vertical load of 25 is set in a range of 75 to 105 ° 9, the proportion of the vertical component is quite small and may even be neglected in the calculation of the nip load. The same applies to non-vertical load -: ***: situations.

. \ 30 • load load instead of screws, a zero load discharge load can be generated even though fluid pressure is applied to the bearing housing between the bearing housing and the bearing outer ring. In this case, it is necessary to prevent the bearing from rotating as the frictional force between the outer periphery and the bearing housing decreases due to the intervening fluid. Fluid penetration throughout this gap can be limited by seals, but the bearing is always safely locked mechanically non-rotating if the risk of rotation is anticipated. The fluid pressure can be applied, for example, to a groove transverse to the bearing periphery in the bearing housing or to a bore pointing towards the periphery. Fluid pressure can also be used for a pulsating load or otherwise variable load. Liquid pressure may also be applied to press the piston 10 or other corresponding pressure member against the outer periphery 6 of the bearing 3 in a manner similar to that of a screw. The advantage of the arrangement is the easier arrangement of load control and variation as well as automation and remote control. The fluid pressure can be replaced by a pressurized gas.

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More than one loading force or member may be used. The advantage of this is a smoother load and a greater available force. One alternative is to provide two or more opposing loading members, whereby the direction of the loading direction can be reversed. This may possibly further reduce wear on the drug.

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Claims (13)

119480 X. A method for reducing the zero load on a bearing (3) of a rotating machine element (1) in a fiber web machine in which the machine element (1) is loaded (Fn) in the loading direction, characterized in that the outer periphery (6) of the bearing with a single loading force (Fo) and at least intermittently in the transverse direction of the shaft (3). Method according to Claim 1, characterized in that the outer circumference (6) of the bearing (3) is loaded with a screw (9) which is pressed onto the outer circumference of the bearing. Method according to Claim 1, characterized in that the outer circumference (6) of the bearing (3) is subjected to fluid pressure. A method according to any one of the preceding claims 1 or 2, characterized in that more than ·· »V 1 2 is applied at a single load force (Fo). • ♦ · • · · »M The method according to any one of the preceding claims, characterized in that the load force (Fo) is applied at an angle of 75 ° to 105 °, preferably 90 °, to the vertical load. - • · · in relation to the loading force, ie the loading force and the gravity of the nip. • e • · * ·· * ϊ # 1 [: A process according to any one of claims 1 to 4: 1. 30, characterized in that the outer circumference (6) of the bearing (3) • · 1 ··· ·. ···. is loaded against the nip load in the transverse direction. e 1 ··· · • · · 2 1j Method according to one of claims 1 to 6, characterized in that the machine member to be loaded is a roll of a calendar, in particular a multi-roll calender. An arrangement for reducing the bearing load of a vertically-loaded rotating machine member (1), the rotary machine member comprising at least an axis (5) and a main bearing (3) of a rolling bearing type mounted on an axis (5), and a bearing housing (4) (3) is mounted, the bearing (3) comprising at least an inner and outer periphery (6, 7) 10 and rolling members (8) therebetween known from at least one loading member (9) differing from the loading direction (FN) of the machine member (1) and to form a transverse load (F0) transverse to the shaft (5) directly on the outer periphery (6) of the bearing (3). 15 Arrangement according to Claim 8, characterized in that the loading members (5 to 7) are arranged at an angle of 75 to 105 °, preferably 90 °, with respect to the vertical loading force. 20 An arrangement according to claim 8 or 9, characterized in that at least one of the loading members is against the medicament. screw (9) fitted to press the outer ring (9) into the hole in the bearing housing. • »· * 25 • ·· Arrangement according to one of Claims 8 to 10, characterized in that the at least one loading member is a fluid pressure adapted to press against the outer periphery (6) of the bearing (3). • · · • · ··· • ♦ • · Arrangement according to one of Claims 7 to 8, characterized in the bearing housing (4) by at least one load member (9) which is provided opposite to the bearing member (9), which permits a • # i: movement of the scroll in the clearance (14). "· 119480 Arrangement according to one of Claims 8 to 12, characterized in that the machine member to be loaded is a roll of a calender, in particular a multi-roll calender, 1 · · 1. * · • · * φ • 1 1 · • · · m * · • • 2 • · · ♦ · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · • · 1 * · · ··· 1 • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ··· 82