FI114036B - Slide shoe assembly for a roll in a paper/board machine has a loading element that is equipped with a mechanism to eliminate for a nip-load induced deflection of the roll shell and/or a deflection of the slide shoe - Google Patents

Abstract

A slide shoe assembly includes a loading element which is equipped with a mechanism to eliminate for a nip-load induced deflection of the roll shell and/or a deflection of the slide shoe that is caused by the pressure of a hydraulic medium. The element is provided to eliminate the harmful effects of deflections on an oil film between the loading shoe and a supported cylindrical surface. The slide shoe assembly comprises a stationary axle (4) mounted with a cylindrical roll shell (2). A clearance (5) is formed between the axle and an inner surface (3) of the roll shell. The roll shell is fitted with a loading elements (11) which are operated by a pressurized hydraulic fluid and provided with slide shoes (10). The slide shoes are loaded against the inner surface of the roll shell to control the distribution of a nip pressure in a nip. The loading element is equipped with a mechanism to eliminate or compensate for a nip-load induced deflection of the roll shell and/or a deflection of the slide shoe that is caused by the pressure of a hydraulic medium. The element is provided to eliminate the harmful effects of deflections on an oil film between the loading shoe and a supported cylindrical surface. An independent claim is also included for a loading shoe for a thin-shelled, deflection-compensated roll (1) in a paper/board machine. The loading shoe is fitted in a loading chamber formed along the roll axle which can be loaded by hydraulic medium present in the loading chamber. The shoe has its sliding surface provided with high-pressure chamber which is in line with the nip to eliminate a directed deformation in the shell.

Description

114036

Slim Shoe Shoe Arrangement of a Thin-Skinned Compensated Roll for a Paper \ Cardboard Machine or Post Processing Machine

The present invention relates to a slip-shoe arrangement of a thin-skinned deflection-compensated roll of a paper / board machine or a finishing machine which comprises a non-rotatable shaft. A rotatable cylindrical roll shell is provided around the shaft, in which the loading elements acting on the pressurized hydraulic fluid are arranged in the free space formed between the inner surface and said shaft. The loading elements comprise sliding shoes arranged in a single axial row of rolls 10, which are loadable against the inner surface of the roll shell to control the nip pressure distribution of the nip formed with the counter roll.

In such thin-skinned rolls, the problem is the bending of the roll mantle radially inwardly due to the nip pressure applied to the roll skirt 15. Bending of the roll shell causes the lubricating oil film between the inside surface of the roll shell and the sliding shoe to thin and even break.

One solution to this problem is disclosed in Finnish Patent Application 880074, which discloses a support arrangement for zone-controlled sliding shoes, which utilizes flexible auto-adjustable walls instead of fixed chambers for the sliding shoes.

It is an object of the present invention to provide a sliding shoe assembly such as those mentioned above, which prevents as much as possible the thinning or worst breaking of the oil film due to the bending of the roll shell.

; * ·. For a paper / board machine or a finishing machine according to the invention, a thin jacket. the slip shoe arrangement of the pressurized deflection roll is essentially 30 characterized in that the slip shoe arrangement comprises a non-pressurized space at the nip allowing the roll sheath due to the nip pressure to bend inwardly, and that the unpressurized space is provided on

In this embodiment, it is preferable that the unpressurized space is an elongated groove extending longitudinally of the roll between opposite sides of the sliding shoe, which opens at each end into said free space.

Further, in this embodiment, it is preferable that the sliding shoe comprises axially stabilizing chambers on either side of the nip, between which a groove is arranged at the nip. There may also be two or more stabilization chambers in axial direction on either side of the nip.

The invention will now be described with reference to certain preferred embodiments of the invention shown in the accompanying figures, in which:

Fig. 1 schematically illustrates an embodiment of a slip-shoe flexural-compensated roller slip shoe assembly according to an embodiment of the present invention.

Figure 2 shows a section II-II of Figure 1.

Figure 3 is an enlarged scale view of the detail III-III of Figure 1 on an enlarged scale.

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* I

Fig. 3A shows the top view of the sliding shoe of Fig. 3, as seen from * »·. ·, *.

• ·; . ·. Figure 1 shows the general construction of a thin-shell deflection compensated roller 1, which is mainly known in the prior art. The roll 1 comprises a non-rotatable shaft 4 around which the cylindrical roll shell 2 is arranged to be rotatable.

The roll shell 2 is mounted on the shaft pins 6a, 6b extending at each end of the shaft 4 with bearings 7a, 7b, leaving a gap between the roll shell 2 and the shaft 4. : free space 5. According to the example, the open ends of the cylindrical roll shell 2 are closed by end flanges 8a, 8b. The roller 1 is driven by an actuator not shown.

• * »» · * »· * I · * · 3 114036

Figures 2, 3 and 3A show a sliding shoe arrangement according to the invention. Fig. 3 is an enlarged scale view III-III of Fig. 1. Roll 1 forms a press nip N together with a backing roll 9. The slip shoe 10 disposed between the inner surface 3 of the roll shell 2 and the shaft 4 comprises loading elements 5 11. The nip pressure of the nip N is adjustable by the loading elements 11 when the cylinders 15 of the loading elements 11 are hydraulically fed from oil channels 13 pressure. The same hydraulic fluid may be introduced through the lubrication channels 16 in the load elements 11 into the stabilization chambers 17 and further into a lubricating film between the sliding surfaces of the sliding shoes 10 and the inner surface 3 of the roll shell 2.

In the slip shoe arrangement according to the invention, each slip shoe 10 has a non-pressurized space 18 at the nip N which allows the roll sheath 2 15 due to the nip pressure to flex freely inward.

An elongated groove 12 is provided between nip N in the circumferential direction of each sliding shoe 10 at a circumferentially adjacent stabilization chamber 17 and extends between the opposite sides 20 of the sliding shoe and opens at both ends into said free space 5. Unpressurized space 18 * · / ·; * is thus formed in the area delimited by the walls 12 of the groove 12 and the inner surface 3 of the roll shell 2. Small leaks in the lubrication film or stabilization chamber 17 into the unpressurized space 18 will not be a disadvantage, since excess hydraulic fluid is discharged from the groove 12; . 'Through open ends to free space 5.

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As best seen in Figure 3, the unpressurised space 18 in particular allows the inner surface 19 of the roll shell 2 to flex freely inward, thereby causing the sliding shoe 10 to · · ·. and the lubricating film between the inner surface 3 of the roll shell 2 remains on the entire sliding shoe 10, ·. substantially the same thickness in the sliding surface.

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Claims (3)

114036 A slip-shoe arrangement of a thin-shell deflection-compensated roll (1) of a paper / board machine or a finishing machine, the roll (1) comprising a non-rotatable shaft (4) surrounded by a rotatable cylindrical roll shell (2) 2) in the free space (5) formed between the inner surface (3) and the load elements (11) operated by a pressurized hydraulic fluid having sliding shoes (10) arranged in one axial row of the roll which are loadable against the inner surface 10 (3) of the roll; for controlling the nip pressure distribution of the nip (N) formed with the counter roll (9), characterized in that the sliding shoe arrangement comprises a non-pressurized space (18) at the nip (N) allowing free nip pressure due to the nip pressure (18) is provided in the sliding shoe 15 () of the loading element (11) for loading the roll jacket (2) 10) at the nip (N). Sliding shoe arrangement according to claim 1, characterized in that the unpressurised space (18) is an elongated groove (12) extending longitudinally of the roll (1) between the opposite sides (20) of the sliding shoe (10). . Sliding shoe arrangement according to claim 2, characterized in that the sliding shoe (10) comprises stabilizing chambers (17) on both sides of the nip (N) in the circumferential direction of the shaft (4), between which the nip (N) the slot (12) * I · 25 is arranged. • I • · 5 114036