RU2389572C2 - Three-roller stand of automatic tube-rolling mill - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, particularly to roll mandrel rolling mills. Three-roller stand of automatic tube-rolling mill comprises body accommodating rollers and rollers drive representing bevel pinions one of which is rigidly fitted on drive shaft. Rollers are rigidly fitted on pinion hubs running in bearing supports mounted on axles rigidly fixed in aforesaid body. Mill stand incorporates another drive shaft carrying the third roller. Aforesaid body is mounted on foundation to move perpendicular to second drive shaft axis. Roller passes have tolerances varying from 31° to 35°.

EFFECT: possibility to use for tube-rolling at automatic mill in to or more stroke, higher quality of rolling due to use of three-roller rolling.

1 dwg

Description

The invention relates to the field of metal forming, and more specifically to mills for rolling on a short mandrel. The utility model can most effectively be used for rolling pipes in an automatic mill in two or more passes.

A two-roll working stand of an automatic tube mill is known, comprising a bed, bearing bearings located on the bed, upper and lower drive shafts installed in bearing bearings, upper and lower rolling rolls mounted on drive shafts, and a mechanism for breeding rolling rolls (see RF patent No. 2084298, B21B 17/02, B21B 39/20, “Automatic pipe rolling mill”, published on July 20, 1997).

A disadvantage of the known working stand is that, due to the variable radius of the roll, which decreases from the edges of the roll to its middle, at points that are different from the middle of the roll, the speed of rotation of the roll is ahead or behind the speed of rotation of the pipe, resulting in slippage causing defects pipes, for example risks. Due to the high degree of uncontrolled deformation during two-roll rolling and uneven distribution of force, an uneven flow of material occurs, which causes ovality and deviation along the pipe wall thickness. In addition, the high rolling force exerted on the two rolls reduces the service life of the rolls.

The closest in technical essence is a three-roll working stand of a reduction mill, containing a housing connected to the drive shaft, cylindrical shafts located therein with drive rolls, bevel gears and bearing bearings, as well as sealing elements, the stand body is made of two halves connected bolted joints, and the sealing elements on the side of the rolls consist of separate blocks and are installed in bores made on both halves of the housing, with each the th cylindrical shaft is made with a hollow bore, coaxial to its axis, and is equipped with a rod installed in this bore and tightening the bearings, roller and bevel gears together (see RF patent No. 2207197, 7 B21b 17/04, B21b 17/14, B21b 13/10, “Three-roll working stand of a reduction mill”, published on 02.27.2003).

The well-known three-roll working stand allows you to get pipes with high quality, but it is used in complex pipe rolling units for pipe reduction and cannot be used in automatic rolling mills due to the fact that it lacks the necessary mechanism for the pipe feed back into the automatic mill sliding rolls.

The technical result of the invention is to improve the quality of rolling pipes in an automatic rolling mill by using three-roll rolling.

The specified technical result is achieved by the fact that in a three-roll working stand of an automatic tube mill containing a housing with two rolls located in it and means of their drive made in the form of bevel gears, while one gear is rigidly fixed to the drive shaft, according to the invention, the rolls are rigidly fixed on the hubs of the gears installed through the bearings on the axes fixed in the housing, the working stand is equipped with a second drive shaft, on which the third roll is located, with installed in the frame with the ability to move perpendicular to the axis of the second drive shaft, while the rolls are made with the angle of the brooks in the range from 31 to 35 °.

Rigid fastening of the rolls on the hubs of the gears installed through the bearings on the axles fixed in the housing allows the drive shaft to transmit rotation to two rolls located at an angle of 120 ° to each other from the drive shaft, which allows you to create a compact two-roll unit, rigidly fixed in the housing.

The presence of a second drive shaft, on which the third roll is located, and the installation of the housing in the bed with the ability to move perpendicular to the axis of the second drive shaft allows the rolls 2 and 3 to be raised relative to the roll 11, providing a degree of freedom of the pipe and the possibility of reverse feed during rolling.

The implementation of the rolls with an angle of release of streams in the range from 31 ° to 35 ° provides free withdrawal of the rolls from the mesh with the pipe when they are raised. The implementation of the rolls with an outlet angle of streams less than 31 ° does not allow to bring the roll out of gearing with the pipe. The implementation of rolls with an outlet angle of streams of more than 35 ° leads to a deterioration in the quality of rolling due to an increase in the uncontrolled rolling zone.

Technical solutions that coincide with the totality of the essential features of the invention have not been identified, which allows us to conclude that the invention meets the condition of patentability “novelty”.

The claimed essential features of the invention, predetermining the receipt of the specified technical result, do not explicitly follow from the prior art, which allows us to conclude that the invention meets the patentability condition "inventive step".

The patentability condition “industrial applicability” is confirmed by the example of a specific implementation of a three-roll working stand of an automatic tube mill.

The drawing shows a three-roll working stand of an automatic tube mill.

The three-roll working stand of the automatic tube mill comprises a housing 1 with rolls 2, 3 located therein and their drive means made in the form of bevel gears 4, 5 and 6. Gear 4 is rigidly mounted on the drive shaft 7. The rolls 2 and 3 are rigidly mounted on the hubs gears 5 and 6, installed through the bearings 8 on the axles 9 fixed in the housing 1, the working stand is equipped with a second drive shaft 10, on which the third roller 11. The housing 1 is mounted in a frame (not shown in the drawing) with the possibility of movement perpendicular to the axis of the second drive shaft 10. The rollers 2, 3 and 11 are formed with an angle of release springs 12 equal to 33 °.

The three-roll working stand of the automatic tube mill operates as follows. The housing 1 is lowered, while the rolls 2 and 3, mounted on the hubs of the gears 5 and 6, also fall down towards the roll 11 and, due to the fact that the angle of the brooks 12 is 33 °, the rolls 2 and 3 freely pass the maximum pipe size equal to its diameter and cover the pipe. Thus, all three rolls 2, 3, and 11 are brought together on the pipe, and the reverse feed rollers (not shown) are divorced. The rolling is carried out in the first forward stroke until the rolled pipe extends completely beyond the rolls 2 and 3. Then, the housing 1 is lifted upward, separating the rolls 2 and 3 from the pipe, and the return feed rollers are brought together on the rolled pipe. The pipe obtained after the first pass is returned to the loading table. Rotate the pipe 180 °. The housing 1 is lowered, the rolls 2 and 3 are brought together with the roll 11, while the reverse feed rollers are bred, and the rolling process is repeated in the second pass. The raising and lowering of the housing 1 is carried out by any known means, for example, a cam mechanism.

Claims (1)

Three-roll working stand of an automatic tube rolling mill, comprising a housing with two rolls located in it and means of their drive made in the form of bevel gears, while one gear is rigidly mounted on the drive shaft, the rolls are rigidly fixed on the hubs of the gears mounted through bearings on the fixed in the axes housing, the working stand has a second drive shaft on which the third roll is located, the housing is installed in the frame with the ability to move perpendicular to the axis of the second when one shaft, and the rollers are made with an angle Product streams ranging from 31 to 35 °.