Technical Area

The invention is related to a press brake which shapes metal based material by bending. More specifically, the invention is related to a hydraulic press brake which significantly reduces energy consumption by the use of servo pumps having four working regions and which, in the meantime, generates electrical power and transmits this generated power to the electrical supply network and which reduces the noise level generated by the system to minimum.

State of the Art

Hydraulic press brakes are machines used for the shaping of metals or metal based material. The said press brakes are driven by at least one motor and are shaping the material to be formed by compressing the material between the upper and lower bending matrix. The upper beam wich carries the upper bending matrix moves up and down vertically and shapes the material according to the form of the lower bending matrix which is in fixed position. The motor driven pump enables the motion of the upper beam. The said pump, pumps hydraulic fluid into the system and enables the up and down motion of the upper beam with the aid of direction control valves. The valves, as of their nature of function, control the flow direction of the hydraulic fluid as well as the pressure and speed. In order to fulfill the function as hydraulic press brake, the valves shall be closed or opened when necessary. With closing the valves the speed of the hydraulic fluid will increase and its temperature will rise. Upon repeating these processes the characteristics of the heated fluid will change, the viscosity will increase. This situation will reduce the motion sensitivity of hydraulic press brakes and the desire result will not be achieved. Further, with closing the valves a significiant noise will occur. Therefore the more valves will be used the mentioned noise will increase incrementally.

In the state of the art; asynchronous motors which provide pressure operate continuously. That means even if the bending operation is not conducted the said motors will operate. Therefore the energy consumption will be high. In this respect, a lot of attempts have been made in order to reduce the energy consumption as well as to eliminate any negative impact resulting from the hydraulic fluid motion. In the U.S. Application nr. US6240758, a hydraulic press equipped with two cylinders of different cross-sections is cited. In the mentioned application the transformation of the oil pumped by the pump which is driven by a servo motor to the cylinder by related transmission means is described. With the pump which is driven by the servo motor the up and down motion of the upper beam and consequently, of the upper bending matrix is realized by the use of direction control valves. As it can be seen in the said application the reserve of the existence of the direction control valves does not preclude the overheating of the hydraulic fluid. Further, no positive impact is seen in the reduction of of the noise level due to this reason.

In the application nr. US20077010171 1 , a servo motor controlled hydraulic press is disclosed. As it can be understood from the description this application is more related to drilling a unidirectional hole like a punch press rather than completing a bending operation like a press brake. Besides, it is understood that the material can be shaped into the desired form.

In the Euoprean patent application nr. EP1387090, a system with one cylinder and two pumps is described. In this system the definition of which pump output will reach the cylinder is controlled by at least direction valve and also by the mentioned direction valve the the outputs of both pumps can be coupled. Also in this document, the up and down motion of the bending matrix is provided by the direction control valves.

All these improvements and developments implemented into the previous technique have not been enough to provide an adequate solution in respect with energy efficiency and saving. In the current technique the high noise level of hydraulic pres brakes, the overheating of the hydraulic fluid due to the high number of valves used and the break points and the high energy consumption of the motor which is the drive necessitate a development in the related technical area.

Objective of the Invention and brief description

The current invention is related to an energy saving hydraulic press brake which meets all the requirements and eliminates all disadvantages mentioned above and provides certain advantages. Based on the state of the art the objective of the invention is to present a hydraulic press brake which significantly reduces energy consumption by the use of servo pumps with 4 working regions, and which also generates electrical energy and transmits it to the electrical supply network.

As a result of the abjective mentioned above together with the achieved energy saving, the generation of the used electrical power while the system is operating (during the freefall of the upper beam) and the feedback of this generated energy as well as the storage into an external storage element and individual use afterwards is provided.

The objective of the invention is to reduce the noise level during operation of the press brake to minimum. So, an environment-friendly and human health-sensitive hydraulic press brake production is aimed.

The other objective of the invention is to minimize the number of valves and so to minimize the enrgy consumption.

Another objective of the invention is to present a hydraulic press brake which is more environment-friendly by using less oil and preventing waste oil at the machine maintenance periods.

In order to achieve the objectives mentioned above the invention includes an upper bending matrix which forms metal sheet material into by bending and which carries the upper beam, at least one lower bending matrix in which the material is compressed between the upper bending matrix, hydraulic cylinders, at least one servo motor generating power to move the said hydraulic cylinders up and down, prefilling valves which enables the freefall of the said upper bending matrix by ensuring the fast suction of hydraulic fluid (oil) into the cylinders, at least one servo motor with four working fields which operates bidirectionally and enables pressure and speed output at both sides, and the said pump- motor duo operates as a generator and generates electrical power as the said pump rotates a motor coupled with said pump with said pump-motor pair which are working as a generator while rotating during free fall because of the weight of said upper beam - in opposite of the working direction as raising the upper beam.

In the preferred applications of the invention the generated useful energy is transmitted to the network through a regenerative module, preferably. The invention, in its preferred applications, includes at least one hydraulic accumulator of a volume of 0.7 liters preferably, and which transmits pressure oil into the system when necessary or sucks oil from the system and compresses in itself.

The current invention is providing many facilities as of its mentioned specifications, in order to realize all the advantages mentioned above and which their details of are below.

The structural specifications and characteristics of the invention and all advantages will be understood more clear by the the figures below and the detailed descriptions which are cited to in these figures, therefore the assessment shall be conducted by taking these figures and detailed descriptions into consideration.

Brief descriptions of the figures

In figure 1 the complete profile view of the hydraulic press brake subject to the invention is seen.

In figure 2 detailed views of sections of the current invention such as the servo motor, servo hydraulic pump, hydraulic manometers and hydraulic accumulator are available. In figure 3 the diagram view of only the left axis (Y1 ) of the hydraulic press brake subject to the invention is seen.

In figure 4 the diagram view of the regenerative module which is required for transmitting the useful energy generated during freefall and which the current invention presents, is seen.

REFERENCE NUMBERS

10. Oil tank

20. Coupling

30. Filter pump

40. Filter motor

50. Servo motor

60. Check valve

70. Ridging

80. Hydraulic block 90. Hydraulic accumulator

100. Elbow bush

0. Servo hydraulic pump

120. Hydraulic manometer

130. Prefilling valve

140. Hydrauic cylinder

150. Upper beam

160. Lower bending matrix

170. Upper bending matrix

80. Controller

190. Oil suction hose

200. Back gauge

210. Hydraulic hose

220. Safey device

230. Front support arm

300. Regenerative module

301. Control unit

302. Input 1

303. Input 2

L1 . Phase 1

L2. Phase 2

L3. Phase 3

Pe. Grounding output

Detailed description of the Invention The invention brings innovation to hydraulic press brakes which bend metal sheet based material. The said invention includes a servo motor (50) and a servo hydraulic pump (1 10) integrated into the said servo motor (50). With the multi quadrant servo pump (1 10) power is transmitted into the system and also to overcome the inertia occurring while the upper beam (150) is moving down (f reef all) the said servo motor (50) has to brake and generates electrical power as like a generator. This generated electrical power is transmitted preferably as useful energy into the system through a regenerative module. As the said multi quadrant servo pump (1 10) operates in the hydraulic press brake system which has a closed circuit, both as pump and motor, this remarkably reduces the noise level of the machine besides generating useful energy. Direction, Quantity and Pressure control valves which took part individually in the previous technique are not needed anymore in this current invention. A servo motor (50) and multi quadrant servo pump (1 10) integrated into the the said servo motor (50) operate instead of the said valves. The hydraulic fluid flow direction of the multi quadrant servo pump (1 10) is controlled by regulating the rotation direction of the servo motor (50) and the pressure of the hydraulic fluid is controlled by regulating the speed of the said servo motor (50). The multi quadrant servo pump (1 10) does not reuire the use of direction control valves. In the previous technique approximately 10 valves were being used in only one axis (Y1 or Y2) whereas in the current technique maximum 6 valves are available. The decrease of the number of valves in the hydraulic press brakes reduces the noise level remarkably and makes the operation system of the machine simplier, reduces overheating problems and therefore reduces the quantity of used hydraulic fluid (oil).

In figure 3 the diagram view of only the left axis (Y1) of the hydraulic press brake is seen. As the right axis (Y2) operates synchronised with the left axis just one diagram is sufficient for the required information. The servo motor (50) is shown as 1.01. The multi quadrant servo pump (110) integrated into the said motor (50) is shown as 1.03. As the servo motor (50) is connected to the said pump (1 10), it transmits the hydraulic fluid (oil) to the cylinders and moves the Y1 axis up and down. During down motion the bending operation is conducted. Upon completing the bending process the servo motor (50) moves the upper beam (150) up by turning the connected pump (1 10) in reverse direction and through the closed circuit hydraulic system. The bidirectional operation of the said pump (110) does not require the use of direction control valves. With the non-implementation of direction control valves into the system the hydraulic liquid fluid does not overheat. Because of situations which require closed valve range the cross-section of the channel in which the fluid flows is getting narrow and the fluid flow speed is (changing) increasing and along with it its temperature rises. In closed circuits the characteristics of the fluid changes (viscosity decreases as temperature rises) by overheat of the said hydraulic fluid which is in a continuous cycle. The hydraulic fluid (oil) which its characteristic of has changed distorts the stability of the upper beam (150) in the hydraulic system. Therefore a high amount of oil shall be used in order to prevent overheat and loss of characteristics of the oil which flows continuously. Besides, an additional cooling system is required in order to achieve an efficient cooling. With this innovation brought with the current innovation oil overheats are eliminated. As a result of this the quantity of used oil decreases and the oil tank is smaller by 75% compared to the previous technique. So, an extensive cooling system is not required and by the decrease of quantity of the oil used possible waste oils are reduced and a more environment-friendly machine is achieved.

The invention includes upper and lower bending matrixes (160, 170) which provide the required form to bend the metal sheet based material. The upper beam (150) which carries the upper bending matrix (170) and which transmits the motion is driven by hydraulic cylinders (140). The hydraulic fluid which transmits the required pressure for motion is kept in the oil tank ( 0). The Accumulator (90) stores the required energy (pressure oil) for the prefilling valves ( 30) in itself. As the said prefilling valves (130) enable the freefall of the upper beam (150) the pressure generated by the pump (1 10) can be read on the hydraulic manometer (120). Decompression valves are shown as 2.10. These said valves (2.10) are opened when the machine has completed the bending process and the high pressure oil in the hydraulic cylinders (140) is discharged. With these valves (2.10) the noise level occurring from the instant discharge of high pressure oil is reduced. Further, decompression valves (2.10) are used for support during charging the hydraulic accumulator (90). The valve shown as 2.04 enables a safe stop of the upper beam in case of power cut. During freefall this valve (2.04) is activated . When stepping to the bending process the said valve (2.04) is deactivated and a counterforce is generated by the check valve (60). It is essential by means of the positioning of the axials of the said counterforce and of holding its position. If a counterforce is not applied the machine will deviate from steady operation. During completion of the bending process and while the upper beam moves jp the said valve (2.04) opens automatically without need to energize and the upper beam (150) moves up quickly. The feature of the check valve (60) is that allows a unidirectional flow. In case of unsufficient pressure the check valve (60) opens and when the pressure decreases it will close. So, a flow-back of the hydraulic fluid (oil) is prevented. In case of power cut the servo motors (50) which drive the system will not hold the moving upper beam (150) steadily as they are deactivated. With these said valves (2.04, 60) the system will lock itself and the upper beam shall not fall down and shall be holded safely.

Additionally, the hydraulic press brake subject to the invention includes also an oil motor (40) and an oil filter (30) which filters the oil in the oil tank (10) and directs it. The coupling (20) increases the motion of the oil motor (40). The safety device (220) ensures the safety during bending process. The oil suction hoses (190) realize the oil transportation from the said oil tank (10) to the prefilling valve (130). The servo motors (50) are connected to the oil tank. The elbow bushes (100) are used at the hydraulic installation for direction changes of the hydraulic hoses (190, 210). Along with them, ridging part (70), back gauge component (200), front support system (230) are available in the said hydraulic press brake.

Considering as a whole, differing from the previous technique the current innovation does not require the use of direction control valves by the use of multi quadrant hydraulic pumps (1 10) operating bidirectionally. Therefore it brings remarkable innovation to the technique by means of energy saving and noise level. With the integration of servo motors (50) no energy is consumed while the machine is not operating. However the asynchronous motors used in the previous state of the art are running even when the machine does not operate a bending process. They stop only with the intervention of a labour. With the servo hydraulic pump (1 10) the servo motor (50) functions as a generator. So, the energy generated by the pump-motor duo (110, 50) is transmitted to the energy network through at least regenerative module (300). Preferrably input 1 (302) is connected to the servo motor (50) drive connected to axial Y1 whereas input 2 (303) is connected to the sevo motor (50) drive connected to axial Y2. By this, the voltage generated by the pump-motor duo (1 10, 50) on both axials, is transmitted to the regenerative module (300). The voltage transmitted to the said module (300) is assessed (filtered and regulated) in the control unit (301 ) taking place in the module and is converted into alternative current. The energy converted into a form usable by the hydraulic press brake is transmitted into the system as useful energy as 3 phase (L1 , L2, L3). With the grounding output (PE) possible leakage current must be transmitted to the ground without giving any harm to the system and the operator. The obtained energy can be stored in an energy storage unit similar to an accumulator which is available in another application of the invention.

Upon performed tests the energy saving rates of the current invention are relatively higher comperad to the previous Technique. As the servo motors (50) are deactive while waiting for the bending process 95% less energy is consumed. Also as the upper beam (150) is at freefall 95% of energy saving is the case. Besides, as the servo motor (50) functions as a generator during completion of the freefall additional energy is transmitted to the system. An energy saving of up to 50% is achieved by the direct control of the direction of the upper beam by the servo pumps (1 10) during bending process. At the end of bending which is also called ironing period, as the upper beam (150) stays for a while at upper position, approximately 84% less energy is consumed. Also in the same way, as the upper beam (150) moves up the hydraulic press brake subject to the invention operates with 70% less energy. Assessed in total the current innovation presents an energy saving of approximately 65% comperad to the previous technique.