ROLL DRIVING APPARATUS FOR ROLLING MILLS

Abstract: Roll driving appts. for a rolling mill employs a single motor and a neck pinion unit consisting of 1st and 2nd pinions in a casing. The 1st and 2nd pinions are respectively connected via 1st and 2nd couplings to 1st and 2nd redn. gears for increasing torque. The 1st and 2nd redn. gears are connected via 1st and 2nd shafts to respective work rolls in a roll stand. Pref. the redn. gears are internal planetary gears and are offset w.r.t. one another going horizontally so as to reduce the inter-axial distance.

Description: The invention relates to a roll driving apparatus for synchronously driving a pair of rolls of a rolling mill according to the first portion of claim 1. In the US-A- 3 495 467 and in the JP-U-58-148347 are disclosed a roll driving apparatus, in which the output shaft of a single motor is connected to a speed reducer. The output shaft of the speed reducer is furnished with distributing gears, called a "cam roller," so as to distribute power to two shafts. The working rolls are connected to the two shafts. The cam roller has to be endure a great torque in order that a torque intensified by the speed reducer may be distributed to the two shafts The cam roller is composed of the two gears, the intermeshing parts of which transmit the torque, so that these gears need to be large in order to transmit the intensified torque mentioned above. Especially in recent plate rolling, the cam roller has tended to become large in size for the reason that the power of the motor reaches 10000 kW and that the driving torque of each of the working rolls needs to be as great as 100 tons-m. JP-A-53-71663 describes a special 2-high rolling mill in which a continuously tensioned strip is passed about the two rolls as an S-shaped loop. One of the requirements for the proper operation of this rolling mill type is that the two rolls are driven at different speeds. In a first embodiment the primary driving motor therefore has a cam roller having two gears associated therewith for distributing the torque of the motor, a speed reducer respectively being connected downstream of each one of said cam roller gears. One of these speed reducers is a planetary reduction gear, the outer sun gear of this planetary reduction gear being driven via a spur gear drive by a secondary controllable motor to permit sensitive control of the speed differences between the two rolls. The required speed difference between the two rolls may also be obtained by using a branched gear train instead of the additional secondary driving motor. An object of the invention is to provide a driving apparatus which can reduce the size of the installation of the whole driving system for driving a pair of rolls by means of power from a single motor. Said object will be solved according to the invention by the featurs of claim 1. Brief Description of the Drawings: Fig. 1 is a fundamental arrangement view of a working roll-driving apparatus which is an embodiment of the present invention, Fig. 2 is a half-sectional view of planetary reduction gears, Fig. 3 is a view showing the meshing situation of gears in the reduction gears of Fig. 2, and Fig. 4 is a fundamental arrangement view showing another embodiment of the present invention. Best Modes for Carrying Out the Invention: In the first embodiment of the invention shown in Fig. 1 a quadruple rolling mill has an outer frame formed in such a manner that right and left stands 45, 47 are connected by joint beams 46, 49. Contained in the outer frame are two back-up rolls 22, 18 which are journaled in bearing boxes 42, 48, and also two working rolls 73, 74 which extend a material to-be-rolled 34 and which are journaled in bearing boxes 41, 80. A hydraulic cylinder 43 and a pressure block 44 for controlling the plate thickness of the material 34 to-be-rolled are mounted on the top part of each bearing box 42 for the back-up roll 42. The working rolls 73, 74 of such a rolling mill are driven as stated below. The power of a single motor 62 is transmitted through a coupling 61 to a cam roller 70 which distributes this power to two shafts. The cam roller 70 is so configured that two gears 71, 72 are included in a casing 70a. As regards the shaft on the upper side, the power distributed to the two shafts by the cam roller 70 is transmitted through a coupling 54 to a speed reducer 53 for intensifying the torque. The power regarding the lower shaft is similarly guided through a coupling 59 to a speed reducer 60. The torques distributed to the two shafts and intensified by the speed reducers in this manner, are respectively transmitted to the aforementioned two working rolls 74, 73 by spindles 50, 51. The cam roller and the two speed reducers 53, 60 are mounted on a base 52. Planetary reduction gears of the inner gearing type as shown in Fig. 2 are employed as each of the torque-intensifying speed reducers 53, 60 of the roll driving system. The input shaft 1 of this speed reducer 53, 60 is supported by bearings 3, 14 and provided with a sun gear 8. A plurality of planet gears 5 mesh with the sun gear 8 and also with an inner gearing wheel 13 which is fixed to a casing 4. An output shaft 9 is provided with pins 7, which are inserted centerally of the planet gears 5, and bearings 6 are so disposed that the planet gears 5 can rollingly rotate relative to the corresponding pins 7. The input shaft 1 is journaled in the bearing 3 embraced by a casing 2, and the bearing 14 embraced by the output shaft 9. The meshing states of the respective gears in this speed reducer are schematically illustrated in Fig. 3. The planet gears 5 numbering three mesh with the gear 8 of the input shaft, and they mesh with the inner gearing wheel 13. Since, in this manner, there are three meshing points, a great torque can be transmitted by small gears, and the size of the speed reducer can be made small. Since the two speed reducers are disposed on the output side of the cam roller, there is the problem that the distance between the upper and lower shafts often increases. On these occasions, as illustrated in Fig. 4, a working roll 19 on one of the sides holding the material to-be-rolled therebetween is made undriven, and an intermediate roll 20 is disposed anew and is driven, whereby the distance between driven rolls 20, 21 can be enlarged. Such a quintuple rolling mill having the five rolls is advantageous in simultaneously achieving the effect that, as stated in the JP-A-112249/1978, the undriven working roll 19 journaled in bearing boxes 40 can have a smaller diameter for reducing the rolling load. In the embodyment of Fig. 4 a cam roller 55 for distributing the power of the motor 62 is provided with three gears 56, 57, 58 contained in a casing 55a. Thus, the rotating directions of the driven rolls are conformed. The interaxial distance of driven rolls may well be more increased by relinquishing the drive of the working roll 21 as well as the intermediate roll 20 and driving reinforcing rolls 22, 28. For decreasing the interaxial distance between both the speed reducers, as shown in Fig. 1 and Fig. 4, the arrayal positions of the two speed reducers 53, 60 are shifted so as not to interfere with each other. Although, in Fig. 1 or 4, the cam roller 70 or 55 is arranged directly on the outgoing side of the motor, it is also possible that reduction gears or speed-up gears having some speed regulation ratio are interposed between the motor and the cam roller as needed in design. Also in this case, an example in which the two speed reducers for the torque intensification are disposed behind the cam roller achieves the effects of the present invention similarly and is naturally covered within the scope of the present invention. According to the embodiments, each of the speed reducers for intensifying the torques behind the cam roller is constructed of the planetary reduction gears shown in Fig. 2, so that it becomes a small-sized speed reducer economically. The two speed reducers are arranged so as to be staggered from each other, whereby the interaxial distance between the speed reducers can be shortened, and at least one of the working rolls on both the sides of the material to-be-rolled is made undriven as shown in Fig. 4, whereby a space for enlarging the interaxial distance of the speed reducers can be provided. Effects of the Invention: According to the present invention, the following effects are attained: 1. Since a cam roller for distributing the power of a single motor is disposed at a stage preceding speed reducers, the transmission torque thereof becomes small, and a small-sized cam roller can be employed. 2. Since planetary reduction gears of the inner gearing type are employed as the speed reducer, meshing parts for torque transmission become complicated, and a great torque can be transmitted by small gears. 3. The planetary reduction gears are so arranged as to be axially staggered from each other, whereby the distance between two shafts can be shortened.

Claims: Roll driving apparatus for synchronously driving a pair of rolls of a rolling mill having a pair of working rolls (19, 21; 73, 74) and a plurality of support rolls (18, 20, 21) comprising a motor (62) for driving a pair of said rolls, a cam roller (55, 70) for distributing the power of said motor (62), a pair of speed reducers (53, 60) coupled with said cam roller (55, 70) and a pair of driving spindles (50, 51) connected with said pair of rolls, wherein each driving spindle (50, 51) is coupled with an output shaft (9) of a separate speed reducer (53, 60) disposed behind the cam roller (55; 70), each speed reducer (53, 60) is designed as an inner gearing type planetary reduction gear mounted in a stationary housing (2, 4) respectively, the two speed reducers (53, 60) are in staggered arrangement to each other in the axial direction of the driving spindles (50, 51). Roll driving apparatus according to claim 1, characterized in that each planetary reduction gear (53, 60) includes an inner gearing wheel (13) fixed on the inside of the casing (4), a sun gear (8) fixed on an input shaft (1) connected with the output side of the cam roller (70), and a plurality of planet gears (5) fixed on an output shaft (9) connected with the spindle (50; 51) and being meshed with both of the sun gear (8) and the inner gearing wheel (13). Roll driving apparatus according to claim 1 or 2, characterized in that at least one of the output shafts (9) of the planetary reduction gears (53, 60) is connected with the spindle (50) of an intermediate roll (20), which is disposed between an undriven work roll (19) and a back-up roll (22) and that the cam roller (55) includes one central driving gear (57) and two lateral driven gears (56; 58). Roll driving apparatus according to claim 1 to 3, characterized in that the input shafts (1) of the speed reducers (53, 60) are journaled in a first bearing (3) mounted in the housing (2) and in a second bearing (14) mounted in the end portion of the output shaft (9). Roll driving apparatus according to claim 1 to 4, characterized in that the both planetary reduction gears (53, 60) and the cam roller (55; 70) are mounted on a common base (52).

Inventors: KIMURA, TOMOAKI, SEKIYA, TERUO
Applicants: HITACHI, LTD.
Application year: 1987
Main classification: B21B35
IPC codes: B21B35