WO2016199055A1

WO2016199055A1 - Extrusion press for non-ferrous metal sections

Info

Publication number: WO2016199055A1
Application number: PCT/IB2016/053393
Authority: WO
Inventors: Davide TURLA
Original assignee: Turla S.R.L.
Priority date: 2015-06-11
Filing date: 2016-06-09
Publication date: 2016-12-15
Also published as: EP3307449A1

Abstract

A press (14) for extruding non-ferrous metal profiles is described, comprising at least one punch (2) controlled by oleodynamic or hydraulic cylinders (3, 4) driven in turn by at least one pump (15) controlled by a motor (11), said pump (15) supplies a control fluid for maintaining the pressure in the cylinders (3, 4) by means of a driving circuit (5). Said pump (15) is an internal gear pump.

Description

"Extrusion press for non-ferrous metal profiles".

* * * *

The present invention refers to an extrusion press for non-ferrous metal profiles.

Extrusion presses for the production of non-ferrous metal profiles usually consist of a p nch controlled by an actuator comprising a piston and a hydraulic cylinder pressurized by one or more pumps.

Currently, the hydraulic system of the extrusion presses essentially consists of two sets of hydraulic pumps, main pumps and auxiliary pumps.

The main pumps are aimed at moving the main parts of the press, providing the required force during the step of extruding the metal in the plastic state and ensuring the required speed during the accessory steps of loading the new material to be extruded between a cycle and the next one.

The auxiliary pumps, of different type and number, are instead normally dedicated to tightly sealing the billet container, driving the main pumps, cooling and filtering the hydraulic oil, and to all the further hydraulic services required for the operation of the machine but not directly involved in the extrusion process per se.

If one of the auxiliary pumps is damaged, the operation of the extrusion press is jeopardized, if not completely prevented, thus causing a production halt.

In order to be rapidly repairable in case of failure, the press needs at least one piece for each type of pump present, both main and auxiliary press, to be available in stock.

Definitely, among the main disadvantages of the extrusion presses for non-ferrous materials there is the high noise of the presses which obliges the professionals to use special personal protective devices.

The high noise level of the current systems imposes the company using the extrusion press to enclose the main pumps with their motors in a soundproof cabin (or to segregate them in a separate compartment) protecting the personnel working close to the press from a high noise level normally well above 85 dB if measured at a distance lower than 10 meters with respect to the main pumps.

EP2000226B1 describes a press for extruding non-ferrous materials comprising an extrusion punch driven by hydraulic cylinders driven in turn by at least one piston pump controlled by a three-phase asynchronous electric motor with low moment of inertia. Disadvantageous^, the pumps used are piston pumps, with a noise so high as not to allow to place the pumps close to the press, if not placing the pumps in a separate soundproof room and then spacing them therefrom by connecting them to the press by means of pipes, and causing a loss of load and a greater and continuous energy expenditure to maintain the press in operation. Moreover, at least one auxiliary pump must be added - referred to as boost pump - to pump the fluid from the tank to the pumps placed in another room.

US2011/023345 Al describes an extrusion press for non-ferrous materials comprising a punch driven by hydraulic cylinders and pistons, a piston pump to maintain the pressure, an electric motor, a multi-phase source of electric power, and a thyristor which connects the motor to the power source for softly starting the motor.

" Drehzahlvariable Pumpenatriebe mit Potenzial zur Energieeinsparung" describes the use of hybrid drives. Among the various possibilities described, there is even the use of internal gear pumps on machines such as presses, elevators and mixers.

It is the object of the present invention to have an extrusion press for non-ferrous materials with lower noise than the presses already on the market.

It is a further object to have an extrusion press with small energy consumption as compared to the normal extrusion presses.

It is another object to obtain an extrusion press with lower production costs than the extrusion presses on the market. It is a still further object to have a press with ordinary and extraordinary maintenance costs lower than those of the presses on the market.

In addition, the simplification of the circuit allows the operation of the machine even with a maximum of any two of the pumps out of order.

In accordance with the invention, such an object is achieved by a press for extruding non-ferrous metal profiles, comprising at least one punch controlled by oieodynamic or hydraulic cylinders driven in turn by at least one pump controlled by a motor, said pump supplies a control fluid for maintaining the pressure in the cylinders by means of a driving circuit, characterized in that said at least one pump is an internal gear pump.

These and other features of the present invention will become more apparent from the following detailed description of the practical embodiment shown by way of a non limiting example in the accompanying drawings, in which:

Figure 1 shows an operating diagram of a conventional extrusion press for non-ferrous materials;

Figure 2 shows an operating diagram of an extrusion press of the invention;

Figure 3 shows a side sectional view of an internal gear pump;

Figure 4 shows a front view of the internal gear pump;

Figure 5 shows a top plan view of an extrusion apparatus of the present invention.

Figure 1 shows a conventional extrusion press 1 for non-ferrous metal profiles, for example made of aluminum, with hydraulic operation and comprises a punch 2 for extruding non-ferrous materials.

Punch 2 is driven by oieodynamic or hydraulic cylinders 3 and 4. A main piston pump 6 supplies the cylinders 3 and 4 with a control fluid to maintain the pressure by means of a driving circuit 5. An auxiliary piston pump 9, controlled by an electric motor 10, supplies the control fluid to a servo-valve 8 which controls in turn a number of auxiliary functions of press 1. A billet loader 100 is placed perpendicularly with respect to press 1 and connected to press 1 close to punch 2.

The rotary movement of the main piston pumps 6 is controlled by an electric motor 11. The rotary movement of the main piston pumps 6 is maintained at constant RPM (revolutions per minute) by motor 11.

Motor 11 is a conventional four-pole, three-phase asynchronous motor, comprising a forced ventilation system or alternatively a synchronous servomotor with permanent magnets. The electric motor 11 is designed to be connected to a frequency converter and is adapted to operate as a brushless DC/ AC motor or as a square-frame asynchronous motor, the rotation speed of which is modified by a drive or inverter, in order to ensure a much higher performance than the conventional asynchronous electric motors.

The invention described includes a new hydraulic circuit (Figure 2) which uses a single pump model on the extrusion press 14, i.e. all movements of press 14 and all the main functions thereof (e.g. container sealing; auxiliary movements) are exclusively carried out by main internal gear pumps 15 which are all of the same size and model. The internal gear pumps 15 are more compact and maneuverable than the external gear pumps and ensure a greater resistance against corrosive agents.

Moreover, the hydraulic circuit is designed so that even if any one or two of the pumps 15 is out of service, the functions of said pump 15 are immediately, and automatically, carried out by one of the other remaining pumps 15, without jeopardizing the operation of press 14.

The extrusion press 14, depicted in Figure 2, comprises the punch 2 controlled by the hydraulic cylinders 3 and 4, the control fluid of which is forced into the driving circuit 5 by at least one internal gear pump 15. Said internal gear pump 15 is controlled in turn by motor 11 which regulates the rotary movement thereof thus determining the RPM to be maintained. The number of revolutions of motor 11 is controlled by an inverter 12 connected to a power source 13. Therefore, the internal gear pumps 15 have a fixed displacement/flow rate, the flow rate change is achieved due to the change in the rotation speed of motor 11.

Press 14 further comprises a tight sealing device of a billet container 20, devices for cooling and filtering the hydraulic oil, 21 and 22 respectively, and further hydraulic services required for the operation of the press but not directly involved in the extrusion process per se. All hydraulic services, as well as further functions which require a hydraulic fluid on press 14, are powered by the hydraulic fluid forced into the hydraulic circuit by internal gear pumps 15.

The internal gear pump 15 is directly connected to motor 11 by means of a flexible coupling.

The internal gear pump 15 (Figures 3 and 4) comprises a fastening flange 151, a hydrodynamic support pinion shaft 154, a housing 152, a cover 153 with a through shaft, a hollow wheel 1511, plain bearings 156, axial plates 157, a stop pin 159 and a radial compensation segment 1514.

The pinion shaft 154 is adapted to be coupled to the hollow toothed wheel 1511 by means of the teeth 1519 which radially protrude outside said pinion shaft 154. Said teeth 1519 are adapted to mesh with teeth 1518 protruding towards the interior of the hollow toothed wheel 1511, thus causing the latter to rotate. During the rotation, the radial forces exerted on the toothed wheel 1511 under pressure are largely absorbed by the hydrostatic bearing 150. Moreover, the pinion shaft 154 is supported by a radial slide bearing 1515 hydrodynamically lubricated.

The space between the teeth 1513 of the hollow toothed wheel 1511 of pump 15 is adapted to draw the fluids, for example oil. During the rotation of the hollow toothed wheel 1511, the liquid enters into the cavities formed between the teeth 1513: when the space between the teeth 1513 is reduced, the volume is reduced and the liquid is pushed outside through an outlet channel 1517. Differently, the external gear pumps comprise at least two rotary elements externally provided with teeth.

The internal gear pump 15 is mounted directly in the tank of press 1, the motor 11 is mounted on pump 15 and fastened to the structure of press 1.

Alternatively, the internal gear pump 15 can be mounted on the ground and connected to the tank by means of a suction pipe.

Using internal gear pumps advantageously allows to achieve the yield standards of the piston pumps but with lower costs in terms of cost of the pump itself, consumption of the gear pumps, and maintenance of the gear pumps.

A further advantage is given by the reduced noise of the gear pumps as compared to the piston pumps, this allowing the manufacturer to mount the pumps directly on the press.

With reference to Figure 5, in a 1:100 scale, and as summarized in the table below, the sound-level measurements carried out between two extrusion cycles of the press of the present invention show acoustic levels which are absolutely not annoying nor harmful to the personnel.

Said acoustic levels result in a reduction of 20-30% as compared to extrusion presses which use piston pumps. The comparison between the press of the present invention and a press with piston pumps was made assuming that the piston pumps are in the same room as the extrusion press, in the same position as the internal gear pumps.

In measurements A and B, the height from the ground is 1.7 m, approximately the average height of an operator; in cases C, D and E, the measurements were carried out at the level of the internal gear pumps mounted on the press. Table.

Another advantage is given by the position of the pumps which are mounted on the press, this reduces the energy consumption of the press as mounting a further auxiliary pump for pumping the oil from the main pumps to the press is not required.

Another advantage is given by the fact that the hydraulic system has been developed so as that each main pump is redundant and that the main pumps can exclude and carry out the functions previously carried out by the auxiliary pumps; this allows to reduce considerably the extraordinary production halts of the press due to a pump out of service.

An additional advantage comes from the employment of a single type of pump, this allows to reduce the maintenance costs and to store only the spare parts for the internal gear pumps in stock.

A further advantage is given by the robustness of the internal gear pumps, they require indeed little maintenance while reducing the costs yet.

Claims

1. A press (14) for extruding non-ferrous metal profiles comprising at least one punch (2) controlled by oleodynamic or hydraulic cylinders (3, 4) driven in turn by at least one pump (15) controlled by a motor (11), said pump (15) supplies a control fluid for maintaining the pressure in the cylinders (3, 4) by means of a driving circuit (5), characterized in that said at least one pump (15) is an internal gear pump.

2. A press (14) according to claim 1, characterized in that the internal gear pump (15) is adapted to drive a tight sealing device for a billet container (20), devices for cooling and filtering (21; 22) the hydraulic oil, and further hydraulic services required for the operation of the press but not directly involved in the extrusion process per se.

3. A press (14) according to claim 1 or 2, characterized in that the internal gear pump (15) comprises a pinion shaft (154) adapted to be coupled to a hollow toothed wheel (1511) by means of teeth (1519) which radially protrude outside said pinion shaft (154), said teeth (1519) being adapted to mesh with teeth (1518) protruding towards the interior of the hollow toothed wheel (1511), thus causing the rotation of the latter.

4. A press (14) according to claims 1-3, characterized in that the overall noise of the press (14) between two extrusion cycles at a distance of 2m from the internal gear pumps (15) is lower than 90 dB.

5. A press (14) according to claims 1-4, characterized in that the overall noise of the press (14) between two extrusion cycles at a distance of 5m from the internal gear pumps (15) is lower than 80 dB.

6. A press (14) according to claims 1-5, characterized in that the overall noise of the press (14) between two extrusion cycles at a distance of 7m from the internal gear pumps (15) is lower than 80 dB.

7. A press (14) according to any one of the preceding claims, characterized in that the internal gear pump (15) has a fixed flow rate, the flow rate change of the pump (15) is achieved by varying the rotation speed of the motor (11) by means of an inverter or brushless motor or servomotor (12).

8. A press (14) according to any one of the preceding claims, characterized in that the pump (15) is mounted inside a fluid tank of the press (14).

9. A press (14) according to any one of the preceding claims, characterized in that the motor (11) is a four-pole, three-phase asynchronous motor, comprising a forced ventilation device.

10. A press (14) according to any one of the preceding claims, characterized in that the motor (11) is a synchronous servomotor with permanent magnets.